seismic responseof masonry infilled rc frames

SEISMIC RESPONSEOF MASONRY INFILLED R.C FRAMES CHAPTER- 1 1.1 INTRODUCTION An earthquake (also known as a quake, tremor or temblor) is the result of a sudden release of energy in the Earth’s crust that creates seismic waves. The seismicity or seismic activity of an area refers to the frequency, type and size of earthquakes experienced over a period of time. Earthquakes are measured with a seismometer; a device which also records is known as a seismograph. The moment magnitude (or the related and mostly obsolete Richter magnitude) of an earthquake is conventionally

reported,

with

magnitude

3

or

lower

earthquakes

being

mostly imperceptible and magnitude 7 causing serious damage over large areas. Intensity of shaking is measured on the modified Mercalli scale. The depth of the earthquake also matters: the more shallow the earthquakes, the more damage to structures (all else being equal).[17] At the Earth’s surface, earthquakes manifest themselves by shaking and sometimes displacing the ground. When a large earthquake epicentre is located offshore, the seabed sometimes suffers landslides and occasionally volcanic activity. In its most sufficient displacement to cause at Tsunami. The shaking in earthquakes can also trigger generic sense, the word earthquake is used to describe any seismic event whether a natural phenomenon or an event caused by humans that generates seismic waves. Earthquakes are caused mostly by rupture of geological faults, but also by volcanic activity, landslides, mine blasts, and nuclear tests. An earthquake’s point of initial rupture is called its focus or hypocentre. The term epicentre refers to the point at ground level directly above the hypocentre. In its most general sense, the word earthquake is used to describe any seismic event — whether natural or caused by humans — that generates seismic waves. Earthquakes are caused mostly by rupture of geological faults, but also by other events such as volcanic activity, landslides, mine blasts, and nuclear tests. An earthquake's point of initial rupture is called its focus or hypocenter. The epicentre is the point at ground level directly above the hypocenter. Earthquakes are measured using measurements from seismometers

Dept. of civil Engineering CMRIT

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SEISMIC RESPONSEOF MASONRY INFILLED R.C FRAMES Earthquake wave may move in any direction and for design purposes, it is resolved into the vertical and horizontal directions. On an average, a value of 0.1 to 0.15g (where g = acceleration due to gravity) is generally sufficient for high dams in seismic zones. In extremely seismic regions and in conservative designs, even a value of 0.3g may sometimes by adopted. Tectonic earthquakes occur anywhere in the earth where there is sufficient stored elastic strain energy to drive fracture propagation along a fault plane. The sides of a fault move past each other smoothly and a seismically only if there are no irregularities or asperities along the fault surface that increase the frictional resistance. Most fault surfaces do have such asperities and this leads to a form of stick-slip behaviour. Once the fault has locked, continued relative motion between the plates leads to increasing stress and therefore, stored strain energy in the volume around the fault surface. This continues until the stress has risen sufficiently to break through the asperity, suddenly allowing sliding over the locked portion of the fault, releasing the stored energy.[2] This energy is released as a combination of radiated elastic strain seismic, frictional heating of the fault surface, and cracking of the rock, thus causing an earthquake. This process of gradual build-up of strain and stress punctuated by occasional sudden earthquake failure is referred to as the elastic-rebound theory. It is estimated that only 10 percent or less of an earthquake's total energy is radiated as seismic energy. Most of the earthquake's energy is used to power the earthquake fracture growth or is converted into heat generated by friction. Therefore, earthquakes lower the Earth's available elastic potential energy and raise its temperature, though these changes are negligible compared to the conductive and convective flow of heat out from the Earth's deep interior.[3] There are three main types of fault, all of which may cause an inter plate earthquake: normal, reverse (thrust) and strike-slip. Normal and reverse faulting are examples of dip-slip, where the displacement along the fault is in the direction of dip and movement on them involves a vertical component. Normal faults occur mainly in areas where the crust is being extended such as a divergent boundary. Reverse faults occur in areas where the crust is being shortened such as at a convergent boundary. Strike-slip faults are steep structures where the two sides of the fault slip horizontally Dept. of civil Engineering CMRIT

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SEISMIC RESPONSEOF MASONRY INFILLED R.C FRAMES past each other; transform boundaries are a particular type of strike-slip fault. Many earthquakes are caused by movement on faults that have components of both dip-slip and strike-slip; this is known as oblique slip. The most important parameter controlling the maximum earthquake magnitude on a fault is however not the maximum available length, but the available width because the latter varies by a factor of 20. Along converging plate margins, the dip angle of the rupture plane is very shallow, typically about 10 degrees. Thus the width of the plane within the top brittle crust of the Earth can become 50 to 100 km making the most powerful earthquakes possible. Strike-slip faults tend to be oriented near vertically, resulting in an approximate width of 10 km within the brittle crust, thus earthquakes with magnitudes much larger than 8 are not possible. Maximum magnitudes along many normal faults are even more limited because many of them are located along spreading centres in Iceland, where the thickness of the brittle layer is only about 6 km.[10][11] In addition, there exists a hierarchy of stress level in the three fault types. Thrust faults are generated by the highest, strike slip by intermediate, and normal faults by the lowest stress levels.[12] This can easily be understood by considering the direction of the greatest principal stress, the direction of the force that 'pushes' the rock mass during the faulting. In the case of normal faults, the rock mass is pushed down in a vertical direction, thus the pushing force (greatest principal stress) equals the weight of the rock mass itself. In the case of thrusting, the rock mass 'escapes' in the direction of the least principal stress, namely upward, lifting the rock mass up, thus the overburden equals the least principal stress. Strike-slip faulting is intermediate between the other two types described above. This difference in stress regime in the three faulting environments can contribute to differences in stress drop during faulting, which contributes to differences in the radiated energy, regardless of fault dimensions. The infill wall is the supported wall that closes the perimeter of a building constructed with a three-dimensional framework structure (generally made of steel or reinforced concrete). Therefore, the structural frame ensures the bearing function, Dept. of civil Engineering CMRIT

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SEISMIC RESPONSEOF MASONRY INFILLED R.C FRAMES whereas the infill wall serves to separate inner and outer space, filling up the boxes of the outer frames. The infill wall has the unique static function to bear its own weight. The infill wall is an external vertical opaque type of closure. With respect to other categories of wall, the infill wall differs from the partition that serves to separate two interior spaces, yet also non-load bearing, and from the load bearing wall. The latter performs the same functions of the infill wall, hygro-thermically and acoustically, but performs static functions too. The use of masonry infill walls, and to some extent veneer walls, especially in reinforced concrete frame structures, is common in many countries. In fact, the use of masonry infill walls offers an economical and durable solution. They are easy to build, attractive for architecture and has a very efficient cost-performance. Today, masonry enclosures and partition walls are mainly made of clay units, but also aggregate concrete units (dense and lightweight aggregate) and autoclaved aerated concrete units are used. More recently, industry is also trying to introduce wood concrete blocks. Partition walls, made with both vertically and horizontally perforated clay blocks, represent two third of the corresponding market. Infill wall types : Single-leaf wall :A wall without a cavity or continuous vertical joint in its plane. Cavity wall: A wall consisting of two parallel single-leaf walls, effectively tied together with wall ties or bed joint reinforcement. The space between the leaves is left as a continuous cavity or filled or partially filled with non-load bearing thermal insulating material. A wall consisting of two leaves separated by a cavity, where one of the leaves is not contributing to the strength or stiffness of the other (possibly load bearing) leaf, is to be regarded as a veneer wall. Veneer wall :A wall used as a facing but not bonded or contributing to the strength of the backing wall or framed structure.

Masonry is the building of structures from individual units, which are often laid in and bound together by mortar; the term masonry can also refer to the units Dept. of civil Engineering CMRIT

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SEISMIC RESPONSEOF MASONRY INFILLED R.C FRAMES themselves. The common materials of masonry construction are brick, building stone such as marble, granite, travertine, and limestone, concrete block, glass block, and cob. Masonry is generally a highly durable form of construction. However, the materials used, the quality of the mortar and workmanship, and the pattern in which the units are assembled can substantially affect the durability of the overall masonry construction. A person who constructs masonry is called a mason or brick layer. Applications Masonry is commonly used for walls and buildings. Brick and concrete block are the most common types of masonry in use in industrialized nations and may be either weight-bearing or a veneer. Concrete blocks, especially those with hollow cores, offer various possibilities in masonry construction. They generally provide great compressive strength, and are best suited to structures with light transverse loading when the cores remain unfilled. Filling some or all of the cores with concrete or concrete with steel reinforcement (typically rebar) offers much greater tensile and lateral strength to structures. Advantages 

The use of material such as bricks and stones can increase the thermal mass of a building and can protect the building from fire.



Masonry is non-combustible product.



Masonry walls are more resistant to projectiles, such as debris from hurricanes or tornadoes.

Disadvantages 

Extreme weather, under certain circumstances, can cause degradation of masonry due to expansion and contractions forces associated with freeze-thaw cycles.



Masonry tends to be heavy and must be built upon a strong foundation, such as reinforced concrete, to avoid settling and cracking.



Other than concrete, masonry construction does not lend itself well to mechanization, and requires more skilled labor than stick-framing.


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SEISMIC RESPONSEOF MASONRY INFILLED R.C FRAMES 

Masonry consists of loose components and has a low tolerance to oscillation as compared to other materials such as reinforced concrete, plastics, wood, or metals.

Structural limitations Masonry has high compressive strength under vertical loads but has low tensile strength (against twisting or stretching) unless reinforced. The tensile strength of masonry walls can be increased by thickening the wall, or by building masonry piers (vertical columns or ribs) at intervals, where practical, steel reinforcements such as wind posts can be added. RC frames with unreinforced masonry infill walls are common in developing countries with regions of high seismicity. Often, engineers do not consider masonry infill walls in the design process because the final distribution of these elements may be unknown to them, or because masonry walls are regarded as non-structural elements. Separation between masonry walls and frames is often not \provided and, as a consequence, walls and frames interact during strong ground motion. This leads to structural response deviating radically from what is expected in the design. An experimental program was designed to test the hypothesis that masonry walls can be used to reduce the vulnerability of RC frames. The object to the program was to investigate whether the RC-brick composite has enough displacement capacity to sustain displacement cycles in the nonlinear range of response. This question was addressed through an experiment in which a full-scale three-story reinforced-concrete structure that had been previously tested to failure was tested a second time after strengthening with brick infill walls. This paper describes the results from these tests and their implications. Most reinforced concrete (RC) frame buildings in developing countries are infilled with masonry walls. Experience during the past earthquakes has demonstrated the beneficial effects as well as the ill-effects of the presence of infill masonry walls. In at least two moderate earthquakes (magnitude 6.0 to 6.5 and maximum intensity VIII on MM scale) in India, RC frame buildings with brick masonry infills have shown excellent performance even though most such buildings were not designed and detailed for seismic response [Jain et al, 1991; 1997]; these buildings are Dept. of civil Engineering CMRIT

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SEISMIC RESPONSEOF MASONRY INFILLED R.C FRAMES characterised by fairly uniform configuration and small panel size (typically about 2.7m × 3.5m with 0.23m masonry thickness). The design codes have, however, been mainly focusing on the malefic effects. The seismic design of masonry infilled RC frame buildings is handled in different ways across the world. Some of the prevalent design practices are: • Infills are adequately separated from the RC frame such that they do not interfere with the frame under lateral deformations. The entire lateral force on the building is carried by the bare RC frame alone. • Infills are built integral with the RC frame, but considered as non-structural elements. The entire lateral force on the building is carried by the bare RC frame alone. This is the most common design practice in the developing countries. • Infills are built integral with the RC frame, and considered as structural elements. The in-plane stiffness offered by the infill walls is considered in the analysis of the building. The forces from this analysis are used in the design of RC frame members and joints. INFLUENCE OF MASONRY INFILL WALLS Significant experimental and analytical research effort has been expended till date in understanding the behaviour of masonry infilled frames [CEB, 1996]. Infills interfere with the lateral deformations of the RC frame; separation of frame and infill takes place along one diagonal and a compression strut forms along the other. Thus, infills add lateral stiffness to the building. The structural load transfer mechanism is changed from frame action to predominant truss action (Figure 1); the frame columns now experience increased axial forces but with reduced bending moments and shear forces.

Fig 1 : Lateral Load Transfer Mechanism Dept. of civil Engineering CMRIT

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SEISMIC RESPONSEOF MASONRY INFILLED R.C FRAMES When infills are non-uniformly placed in plan or in elevation of the building, a hybrid structural load transfer mechanism with both frame action and truss action, may develop. In such structures, there is a large concentration of ductility demand in a few members of the structure. For instance, the soft-storey effect (when a storey has no or relatively lesser infills than the adjacent storeys), the short-column effect (when infills are raised only up to a partial height of the columns), and plan-torsion effect (when infills are unsymmetrically located in plan), cause excessive ductility demands on frame columns and significantly alter the collapse mechanism. Another serious concern with such buildings is the out-of-plane collapse of the infills which can be life threatening. Infills possess large lateral stiffness and hence draw a significant share of the lateral force. When infills are strong, strength contributed by the infills may be comparable to the strength of the bare frame itself. The mode of failure of an infilled building depends on the relative strengths of frame and infill (Table 1). And, its ductility depends on the (a) infill properties, (b) relative strengths of frame and infill, (c) ductile detailing of the frame when plastic hinging in the frame controls the failure, (d) reinforcement in the infill when cracking in infills controls the failure, and (e) distribution of infills in plan and elevation of the building. Table 1: Modes Of Failures Of Masonry Infilled Rc Frames Weak infil Weak frame

Strong infill -



Diagonal cracks in infill



Plastic hinges in columns

Frame with weak joints



and strong members

Corner crushing of infills



Cracks in beam column joints

Strong frame





Horizontal sliding

Diagonal cracks in infill



Cracks in beamcolumn joints -

in infills


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SEISMIC RESPONSEOF MASONRY INFILLED R.C FRAMES In a bare frame, inelastic effects in RC frame members and joints cause energy dissipation, while in an infilled frame, inelastic effects in infills also contribute to it. Thus, energy dissipation in an infilled frame is higher than that in the bare frame. If both frame and infill are detailed to be ductile, then stiffness degradation and strength deterioration under cyclic loading are nominal. However, if inelastic effects are brittle in nature (e.g., cracking of infill, bond slip failure in frame, or shear failure in frame members), the drop in strength and stiffness under repeated loading may be large. When physical gaps exist between the frame and the infills, or when sliding takes place in infills along mortar beds, the hysteresis loops demonstrate increased pinching. The characteristics of typical buildings in Turkey include flexible columns, soft stories, non seismic detailing, and strong beam-weak column systems. It was also observed that a great majority of these buildings had inadequate lateral stiffness. Therefore, a large number of reinforced concrete (RC) buildings damaged in recent earthquakes required extensive strengthening and repairing. The authors define strengthening as the rehabilitation to upgrade the strength of existing structures. Strengthening made by adding RC infills to the selected bays also increases the lateral stiffness of the structure significantly. Different methods and techniques have been developed and applied in the past three decades to strengthen existing structures (Wyllie 1996; Ersoy 1996; Sugano 1996). These strengthening techniques for framed structures include addition of infill walls, addition of wing walls, concrete jacketing of columns, single and multiple precast panel walls with and without openings, steel bracings, and steel frames (Higashi and Kokusho 1975; Kahn and Hanson1979; Liauw and Kwan 1985; Jirsa and Kreger 1989; Phan and Lew 1996). In these studies, the loading histories were either monotonic or cyclic (Endo, Adachi, and Nakanishi 1980; Higashi et al. 1980; Sugano and Fujimara 1980; Ohki and Bessho 1980; Hayashi, Niwa, and Fukuhara 1980). Many different types of connections of the infill wall to the surrounding frame were also studied, such as shear keys, dowels, and chemical anchors (Sugano 1980; Aoyama et al. 1984). Although almost all tests in the literature were performed on one-bay, one-story frames, there are some tests on one-bay, three-story frames (Higashi, Endo, and Shimizu 1982, 1984). Studies showed that the benefit of strengthening non ductile RC frames might be limited due to the failure of splices in Dept. of civil Engineering CMRIT

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SEISMIC RESPONSEOF MASONRY INFILLED R.C FRAMES the existing column made above the floor level (Valluvan, Kreger, and Jirsa 1993). Feasibility studies on different methods of seismic upgrading were also performed (Miller and Reaveley 1996; Gregorian and Gregorian 1996). It has been concluded that the simplest and the most effective way of improving the behaviour of such buildings, where unsatisfactory seismic behaviour is inherent in the structural system, is to provide an adequate number of structural walls. Such walls not only increase the lateral stiffness significantly but also relieve the existing non-ductile frames from carrying large lateral forces. In Turkey, rehabilitation of frames damaged in earthquakes by introducing RC infills was first applied after the 1969 Bartin earthquake. Starting with the 1992 Erzincan earthquake, structural rehabilitation by RC infills has been used extensively. As a result of these rehabilitation projects, there has been a significant increase in research related to rehabilitation. A review related to RC-infilled frames in the literature shows that the first published experimental research in this area is the one reported by Ersoy and Uzsoy in 1971 (Ersoy 1971). The researchers tested nine 1/2scale, one-story, one bay frames with RC infills under monotonic loading. It was concluded that the presence of the infill increased the lateral load capacity of the frame and reduced the lateral displacement at failure significantly. Subsequently, several research projects were carried out on one-bay, two-story frames at METU Structural Mechanics Laboratory (Altin, Ersoy, and Tankut 1992; Sonuvar 2001). Some tests were also made at the Bogazici University as a part of this program. 1.2Earthquake engineering The branch of science that deals with the study of earthquake and the structure of the earth is termed as earthquake engineering. Earthquake engineering is the study of the behaviour of buildings and structures subject to seismic loading. It is a subset of both structural and civil engineering. The main objectives of earthquake engineering are: 

Understand the interaction between buildings or civil infrastructure and the ground.


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Foresee the potential consequences of strong earthquakes on urban areaand civil infrastructure.



Design, construct and maintain structures to perform at earthquake exposure up to the expectations and in compliance with building codes.



A properly engineered structure does not necessarily have to be extremely strong or expensive.



The most powerful and budgetary tools of earthquake engineering are vibration control technologies and, in particular, base isolation.

HISTORY OF EARTHQUAKE The scientific study of earthquakes is comparatively new. Until the 18th century, few factual descriptions of earthquakes were recorded, and the natural cause of earthquakes was little understood. Those who did look for natural causes often reached conclusions that seem fanciful today; one popular theory was that earthquakes were caused by air rushing out of caverns deep in the Earth's interior. The earliest earthquake for which we have descriptive information occurred in China in 1177 B.C. The Chinese earthquake catalog describes several dozen large earthquakes in China during the next few thousand years. Earthquakes in Europe are mentioned as early as 580 B.C., but the earliest for which we have some descriptive information occurred in the mid-16th century. The earliest known earthquakes in the Americas were in Mexico in the late 14th century and in Peru in 1471, but descriptions of the effects were not well documented. By the 17th century, descriptions of the effects of earthquakes were being published around the world although these accounts were often exaggerated or distorted. The most widely felt earthquakes in the recorded history of North America were a series that occurred in 1811-1812 near New Madrid, Missouri. A great earthquake, whose magnitude is estimated to be about 8, occurred on the morning of December 16, 1811. Another great earthquake occurred on January 23, 1812, and a third, the strongest yet, on February 7, 1812. Aftershocks were nearly continuous between these great earthquakes and continued for months afterwards. These Dept. of civil Engineering CMRIT

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SEISMIC RESPONSEOF MASONRY INFILLED R.C FRAMES earthquakes were felt by people as far away as Boston and Denver. Because the most intense effects were in a sparsely populated region, the destruction of human life and property was slight. If just one of these enormous earthquakes occurred in the same area today, millions of people and buildings and other structures worth billions of dollars would be affected.

Fig 2 : San Francisco earthquake An earthquake is the vibration, sometimes violent, of the Earth's surface that follows a release of energy in the Earth's crust. This energy can be generated by a sudden dislocation of segments of the crust, by a volcanic eruption, or event by manmade explosions as shown in ( Fig 2). Most destructive quakes, however, are caused by dislocations of the crust. The crust may first bend and then, when the stress exceeds the strength of the rocks, break and "snap" to a new position. In the process of breaking, vibrations called "seismic waves" are generated. These waves travel outward from the source of the earthquake along the surface and through the Earth at varying speeds depending on the material through which they move. Some of the vibrations are of high enough frequency to be audible, while others are of very low


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SEISMIC RESPONSEOF MASONRY INFILLED R.C FRAMES frequency. These vibrations cause the entire planet to quiver or ring like a bell or tuning fork. A fault is a fracture in the Earth's crust along which two blocks of the crust have slipped with respect to each other. Faults are divided into three main groups, depending on how they move. Normal faults occur in response to pulling or tension; the overlying block moves down the dip of the fault plane. Thrust (reverse) faults occur in response to squeezing or compression; the overlying block moves up the dip of the fault plane. Strike-slip (lateral) faults occur in response to either type of stress; the blocks move horizontally past one another. Most faulting along spreading zones is normal, along subduction zones is thrust, and along transform faults is strike-slip. Geologists have found that earthquakes tend to reoccur along faults, which reflect zones of weakness in the Earth's crust. Even if a fault zone has recently experienced Another earthquake could still occur. In New Madrid, a great earthquake was followed by a large aftershock within 6 hours on December 6, 1811. Furthermore, relieving stress along one part of the fault may increase stress in another part; the New Madrid earthquakes in January and February 1812 may have resulted from this phenomenon. The focal depth of an earthquake is the depth from the Earth's surface to the region where an earthquake's energy originates (the focus). Earthquakes with focal depths from the surface to about 70 kilometres (43.5 miles) are classified as shallow. Earthquakes with focal depths from 70 to 300 kilometres (43.5 to 186 miles) are classified as intermediate. The focus of deep earthquakes may reach depths of more than 700 kilometres (435 miles). The focuses of most earthquakes are concentrated in the crust and upper mantle. The depth to the centre of the Earth's core is about 6,370 kilometres (3,960 miles), so event the deepest earthquakes originate in relatively shallow parts of the Earth's interior. The epicentre of an earthquake is the point on the Earth's surface directly above the focus. The location of an earthquake is commonly described by the geographic position of its epicentre and by its focal depth.


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SEISMIC RESPONSEOF MASONRY INFILLED R.C FRAMES Earthquakes beneath the ocean floor sometimes generate immense sea waves or tsunamis (Japan's dread "huge wave"). These waves travel across the ocean at speeds as great as 960 kilometres per hour (597 miles per hour) and may be 15 meters (49 feet) high or higher by the time they reach the shore. During the 1964 Alaskan earthquake, tsunamis engulfing coastal areas caused most of the destruction at Kodiak, Cordova, and Seward and caused severe damage along the west coast of North America, particularly at Crescent City, California. Some waves raced across the ocean to the coasts of Japan. Liquefaction, which happens when loosely packed, water-logged sediments lose their strength in response to strong shaking, causes major damage during earthquakes. During the 1989 Loma Prieta earthquake, liquefaction of the soils and debris used to fill in a lagoon caused major subsidence, fracturing, and horizontal sliding of the ground surface in the Marina district in San Francisco. Landslides triggered by earthquakes often cause more destruction than the earthquakes themselves. During the 1964 Alaska quake, shock-induced landslides devastated the Turnagain Heights residential development and many downtown areas in Anchorage. An observer gave a vivid report of the breakup of the unstable earth materials in the Turnagain Heights region: I got out of my car, ran northward toward my driveway, and then saw that the bluff had broken back approximately 300 feet southward from its original edge. Additional slumping of the bluff caused me to return to my car and back southward approximately 180 feet to the corner of McCollieand

Fig 3 : San Andreas Fault Dept. of civil Engineering CMRIT

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SEISMIC RESPONSEOF MASONRY INFILLED R.C FRAMES The goal of earthquake prediction is to give warning of potentially damaging earthquakes early enough to allow appropriate response to the disaster, enabling people to minimize loss of life and property. A primary goal of earthquake research is to increase the reliability of earthquake probability estimates. Ultimately, scientists would like to be able to specify a high probability for a specific earthquake on a particular fault within a particular year. Scientists estimate earthquake probabilities in two ways: by studying the history of large earthquakes in a specific area and the rate at which strain accumulates in the rock. Largest earthquakes by magnitude This list is biased towards recent years due to development and widespread deployment of seismometers. Also, records that were detailed enough to make magnitude Rank Date May 1 1960 March 2 1964 3 4 5 6 7 8 9 10

Location 22,

Valdivia, Chile

27, Prince William Sound, Alaska, United States

December 26, 2004 March 11, 2011 November 4, 1952 August 13, 1868

Indian Ocean, Sumatra, Indonesia Pacific Ocean, Tōhoku region, Japan Kamchatka, Russian SFSR, Soviet Union Arica, Chile (then Peru)

Pacific Ocean, USA and Canada January 26, (then claimed by the Spanish 1700 Empire and the British Empire) Pacific Ocean, Tōhoku region, July 9, 869 Japan April 2, Chittagong, Bangladesh (then 1762 Kingdom of Mrauk U) November Sumatra, Indonesia (then part of 25, 1833 the Dutch East Indies)


Event 1960 Valdivia earthquake 1964 Alaska earthquake 2004 Indian Ocean earthquake 2011 Tōhoku earthquake 1952 Kamchatka earthquakes 1868 Arica earthquake

Magnitude 9.4–9.6 9.2 9.1–9.3 9.1[3] 9.0[4] 8.5–9.0 (est.)

1700 Cascadia 8.7–9.2 earthquake (est.) 869 Sanriku 8.9 (est.) earthquake 1762 Arakan 8.8 (est.) earthquake 1833 Sumatra 8.8 (est.) earthquake

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SEISMIC RESPONSEOF MASONRY INFILLED R.C FRAMES 1.3 Types of earthquake 1. On the basis of location A) Inter plate: The earthquake which occur along the boundaries of the tectonic plates are called inter plate earthquake. Ex: Some areas of the world that are particularly prone to such events include the west coast of North America (especially California and Alaska), the northeastern Mediterranean region (Greece, Italy, and Turkey in particular), Iran, New Zealand, Indonesia, India, Japan, and parts of China. B) Intra plate: The earthquake which occur within the plate itself away from the tectonic plate boundaries are termed as intra plate earthquake. Ex: Examples of damaging intra plate earthquakes are the devastating Gujarat earthquake in 2001, the 2012 Indian Ocean earthquakes, the 1811-1812 earthquakes in New Madrid, Missouri, and the 1886 earthquake in Charleston, South Carolina. 2. On the basis of their cause a) Non-tectonic earthquake: The earthquakes which are of non-tectonic origin are termed as non-tectonic earthquake. These are further classified as; i) Superficial earthquake: The earthquake which are caused by dynamic agencies operating upon the surface of the earth. ii) Volcanic earthquake :The earthquake which occur due to different volcanic activities. Ex: An example is the 2007–2008 Nazko earthquake swarm in central British Columbia, Canada. b) Tectonic earthquake: the earthquakes which are of tectonic origin and occur due to structural disturbances within the earth’s crust are called as tectonic earthquakes. 3.On the basis of focal depth a) Shallow earthquake: The earthquakes in which focal depth is limited up to 71km are called shallow earthquake. Ex : 1994 earthquake in Los Angeles Dept. of civil Engineering CMRIT

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SEISMIC RESPONSEOF MASONRY INFILLED R.C FRAMES b) Intermediate earthquake: Those earthquakes in which focal depth varies from 71km to 300km are termed as intermediate earthquakes. c) Deep earthquake: Those earthquakes in which focal depth is greater than 399km are termed as deep earthquake. Ex: An example of a deep focus earthquake was the 6.8 magnitude quake that occurred 349 km under the Sea of Japan on July 2007, 140 km off the coast of Honshu 4. On the basis of magnitude : ( Fig 4 )shows the effect of Major earthquake a) Micro earthquake (M=3.0) b) Intermediate earthquake (M=3-4) c) Moderate earthquake (M=5-5.9) Ex: 1980 Earthquake in Iraq d) Strong earthquake (M= 6-6.9) Ex: Provence earthquake in France e) Major earthquake (M= 7-7.9) Ex: Sicily earthquake in Italy f) Great earthquake (M>8.0) Ex: 1950 Assam–Tibet earthquake in INDIA

fig 4 Earth quake effect on roads


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SEISMIC RESPONSEOF MASONRY INFILLED R.C FRAMES 1.4 Causes of Earthquake 1. Superficial causes: Earthquakes of mild intensity which occur over the ground surface caused by the dynamic agencies operating upon the surface of the earth are termed as superficial ones. The various surface causes providing seismic tremors are: i) A huge landslide or a rock fall along hill slope. ii) Giant sea waves and crashing breakers along sea shores. iii) Running water, descending falls and cascades upon valley floor. iv) Heavy vibrating machinery in Industrial area. v) Movement of locomotives and other heavy vehicles on earth surface. vi) Man made explosives and other nuclear tests. vii) Mining blasts in mining areas. viii) Large scale heavy excavations causing land subsidence, which sets minor tremors in the vicinity. Some of the other causes seismic shocks are due to cultural noise or disturbed vibrations generated by industry and the traffic. 2. Volcanic causes: Volcanic activities taking place indifferent parts of the World. Often produce volcanic explosions during which the surface the earth trembles. The thus generated is sometime so strong that it causes earthquakes in the nearby areas. Volcanic earthquakes caused by high pressure exerted by movement of molten lava is known as magma with in the earth’s crust are generally shallow earthquakes of mild intensity. Peninsular and extra – peninsular India have observed volcanic activity on a large scale in the past bay of Bengal and Andaman regions have extinct volcanoes. 3. Tectonic causes: Tectonic causes are those which originate within the earth’s crust and are necessarily associated with the relative movement of rock masses forming the crust of the earth. The seismic shocks which occur due to sudden release of enormous strain owing to crustal movements are termed as tectonic earthquake. It established that all major earthquake causing large scale devastation on the surface of the earth are of tectonic origin. Tectonic earthquake occur due to:i) Displacement of rock masses along pre-existing cracks or faults.


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SEISMIC RESPONSEOF MASONRY INFILLED R.C FRAMES ii) Development of new fault planes. Bhuj earthquake in Gujarat (INDIA) in the year 2001 was also of tectonic origin.

1.5 Earthquake zones of India

Fig 5 Earthquake hazard zoning map of India

The latest version of seismic zoning map of India given in the earthquake resistant design code of India [IS 1893 (Part 1) 2002] assigns four levels of seismicity for India in terms of zone factors. In other words, the earthquake zoning map of India divides India into 4 seismic zones (Zone 2, 3, 4 and 5) unlike its previous version, which consisted of five or six zones for the country. According to the present zoning map, Zone 5 expects the highest level of seismicity whereas Zone 2 is associated with the lowest level of seismicity.]

Zone 5 Zone 5 covers the areas with the highest risks zone that suffers earthquakes of intensity MSK IX or greater. The IS code assigns zone factor of 0.36 for Zone 5. Structural designers use this factor for earthquake resistant design of structures in Dept. of civil Engineering CMRIT

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SEISMIC RESPONSEOF MASONRY INFILLED R.C FRAMES Zone 5. The zone factor of 0.36 is indicative of effective (zero periods) level earthquake in this zone. It is referred to as the Very High Damage Risk Zone. The region of Kashmir, the western and central Himalayas, North and Middle Bihar, the North-East Indian region and the Rann of Kutch fall in this zone. Generally, the areas having trap rock or basaltic rock are prone to earthquakes.

Zone 4 This zone is called the High Damage Risk Zone and covers areas liable to MSK VIII. The IS code assigns zone factor of 0.24 for Zone 4. The Indo-Gangetic basin and the capital of the country (Delhi), Jammu and Kashmir fall in Zone 4. In Maharashtra, the Patana area (Koyananager) is also in zone no-4. In Bihar the northern part of the state like- Raksaul, Near the border of India and Nepal, is also in zone no-4. Zone 3 The Andaman and Nicobar Islands, parts of Kashmir, Western Himalayas fall under this zone. This zone is classified as Moderate Damage Risk Zone which is liable to MSK VII and also 7.8 The IS code assigns zone factor of 0.16 for Zone 3. Zone 2 This region is liable to MSK VI or less and is classified as the Low Damage Risk Zone. The IS code assigns zone factor of 0.10 (maximum horizontal acceleration that can be experienced by a structure in this zone is 10% of gravitational acceleration) for Zone 2. 1.6.1 Requirements for enclosure systems Masonry enclosure walls systems, must meet some structural and nonstructural requirements. a. Structural The requirements relating structural stability are currently defined and regulated by Eurocode 6 for load bearing masonry structures and by Eurocode 8 for seismic safety. These codes impose requirements for masonry walls, particularly noncollapse (in-plane/out of plane) and damage limitation, providing methods of calculation to ensure these two requirements. Some of the non-structural requirements are: fire safety, thermal comfort, acoustic comfort, durability and water leakage. Dept. of civil Engineering CMRIT

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SEISMIC RESPONSEOF MASONRY INFILLED R.C FRAMES b. Fire safety The safety against fire is one of the requirements that is often required to enclosures walls. However, as usually the more traditionally used materials (blocks, bricks and mortar) are not fuel products, it is relatively easy to achieve the requirements relating to the limitation of spread of fire, thermal insulation and structural strength, which in severe cases, must be guaranteed for 180 minutes. c. Thermal comfort The thermal comfort is a requirement that the enclosure walls must comply. This requirement has a direct influence on the construction of the walls. The thermal regulations are demanding increasingly higher values of thermal resistance to the walls. To meet these demands new products and building systems, which ensure that the thermal resistances requested by the regulations will be provided, are developed. It is likely that in the near future traditional construction solutions with double leaf walls (with new, more thermally efficient bricks and blocks) will be adapted, and there will be increased use of thermal insulation systems for exterior (ETICS), such as use of single leaf walls. Also the use of insulation systems from the inside will increase. The development of new enclosure wall systems should, apart from trying to improve requisites relating to structural stability in case of earthquake, improve the thermal resistance of the solution.

d. Durability and waterproofing To ensure durability and waterproofing, the most important thing is to avoid errors in design and construction, leading to the appearance of (structural and nonstructural) pathologies. Some requisites that the walls must have in order to avoid pathologies are: adequate expansion joints, correct support of the walls in the correction of thermal bridges, appropriate clipping between masonry leafs, correct implementation of space between leafs, proper placement of thermal insulation. The proper use of paints, protection against moisture and the correct preparation and application of traditional plasters, among others, are important factors


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SEISMIC RESPONSEOF MASONRY INFILLED R.C FRAMES 1.6.2. Interaction between buildings and masonry infill a. Global behaviour When there is a perimeter contact between the masonry infill walls and the frame, in ordinary situations of adherent robust infill walls, the effect of stiffness increase (and also dissipation) influences the building response. In the case of infill walls built disconnected from the structure (not in adherence with the frame elements), it is likely that infill walls act as an additional mass applied to the structure only, and should not have other significant effects. In general, in the most frequent case of perimeter contact between the masonry panels and the beams and columns of the RC structure, the infill panels interact with the structure, regardless of the lateral resistance capacity of the structure, and act like structural elements, overtaking lateral loads until they are badly damaged or destroyed. In this case, the most important effects of the structure-infill interaction are: Increased lateral rigidity of the structure; in the case of flexible structures from seismic zones with small values of the period , the seismic forces increase over the normal level; Creating some vertical irregularities by increasing the ductility demand at one storey or creating some horizontal irregularities by increasing the ensemble torsion as a result of modifying the centre of rigidity; for the design of buildings in seismic zones, these situations must be always avoided; Creating some solicitations of short elements type, having a risk of rupture to shear force, due to the fact that on the deformable zone of the column the shear force is substantially larger than in the normal case (also treated as local effect). b. Local behaviour The main problems in the local interaction between frame and infill are the formation of short beam, short column effect in the structural elements. The zones in which supplementary shear forces can occur, acting locally on the extremities of the beams and columns, should be dimensioned and transversally reinforced in order to overtake safely these forces.


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SEISMIC RESPONSEOF MASONRY INFILLED R.C FRAMES 1.7 LITERATURE REVIEW In this a review of recent research are presented on comparative study of seismic performance evaluation of frame structure with and without infill walls. Hence we need to undergo the detailed study regarding the seismic action on differential behaviour of these structures. Some of the literature reviews has been studied below. Ozgur Anil, et.al,(2007)[1], made “An Experimental Study On Reinforced Concrete Partially In-filled Frames”. The behaviour of partially in-filled reinforced concrete frames subjected to lateral cyclic loading. And also it investigates the behaviour of ductile reinforced concrete frames strengthened by introducing partial in-fills. The test results that partially in-filled RC frame exhibits significantly higher ultimate strength and higher initial stiffness than bare frame. And also it is observed that the aspect ratio of infill wall was increased, the lateral strength and rigidity were also increased. And it shows that the partial infill walls both connected to the column and beam of the frame showed the most successful behaviour. Santiago Pujol, et.al, (2008)[2], studied on “Masonary Infill walls: An Effective Alternatives for Seismic Strengthening of Low-Rise Reinforced Concrete Building Structures”. Full-scale three-story flat-plate structure was strengthened with infill brick walls and tested under displacement reversals. The results of this test were compared with results from a previous experiment in which the same building was tested without infill walls. In the initial test, the structure experienced a punching shear failure at a slab-column connection. The addition of infill walls helped to prevent slab collapse and increased the stiffness and strength of the structure. The measured drift capacity of the repaired structure was 1.5 %. A numerical model of the test structure was calibrated to match experimental results. Numerical simulations of the response of the strengthened structure to several scaled ground motion records suggest that the measured drift capacity would not be reached during strong ground motion.

J. Dorji and D.P. Thambiratnam, (2009)[3], carried experiments on “Modelling and Analysis of Infilled Frame Structure under seismic Loads”. First develops an appropriate technique for modelling the infill-frame interface and then uses it to study Dept. of civil Engineering CMRIT

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SEISMIC RESPONSEOF MASONRY INFILLED R.C FRAMES the seismic response of in-filled frame structures. Finite element time history analysis under different seismic records have been carried out and the influence of infill strength, openings and soft-storey phenomenon are investigated. Results in terms of tip deflection, fundamental period, inter-storey drift ratio and stresses are presented and they will be useful in the seismic design of in-filled frame structures. Kashif Mahmud, et.al, (2010)[4], studied on “The Reinforced Concrete Frame with Brick Masonry Infill due to Lateral Loads”. The behaviour of reinforced concrete frames with brick masonry infill for various parametric changes and their influence in deformation patterns of the frame were observed. And also it deals to find the effect of soft storey on frame structures due to horizontal loading. The analysis of the frame structures is carried out by using ANSYS 5.6. And this analyses results that when the number of bay increases the deflection eventually decreases. And also it is found that when the beam and column size increases the deflection pattern decreases with increased stiffness. And it recommends to analysis the cost-benefit to find out the relative economy that may be achieved if infill is considered as a structural element. Wackchaure M.R, et.al, (2012)[5], made an investigation on “Earthquake Analysis of High Rise Buildings with and without In-filled Walls”. For the analyses, G+9 RCC frames building is modelled and effect of masonry walls on high rise building is studied. Linear dynamic analysis on high rise building with different is carried out. Earthquake time history is applied to the models and various cases of analysis are carried out using E-TABS. Base shear, storey displacement, storey drift is calculated and compared with models. The results concluded that the infill walls reduce displacement, time period and increases base shear. And so it is essential to consider the effect of masonry infill for the seismic evaluation of moment resisting reinforced concrete frame. Mulgund G.V, (2012)[6], studied on “Seismic Assessment of RC Frame Buildings with Brick Masonry In-fills”. Five reinforced RC framed building with brick infill were designed for seismic hazard in accordance with is code taking into consideration of effect of masonry. And also investigation has been made to study the behaviour of RC frames with various configuration of infill when subjected to dynamic earthquake loading. The comparison is made between the results of bare frame and with infill effect. The results furnished were the calculation of earthquake forces by treating RC Dept. of civil Engineering CMRIT

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SEISMIC RESPONSEOF MASONRY INFILLED R.C FRAMES frames as ordinary frames without regards to infill leads tom under estimation of base shear. Therefore it is essential for the structural system to be selected with in-filled walls. G.C Manos, et.al, (2012)[7], studied on “The Behaviour of Masonry Assemblages and Masonry Infilled RC Frames Subjected to Combined Vertical and Horizontal Seismic Type Loading”. The masonry in-filled reinforced concrete frames are subjected to combined vertical and horizontal loads. And to validate different modelling techniques for the numerical simulation of nonlinear behaviour of masonry joints under shear loading. And also it examined the influence of different forms of interface between the masonry infill and the surrounding RC frame and also examines the influence of stiffness, load bearing capacity. From the analysis it is observed that numerical simulation of masonry infilled RC frames having their infill repaired with reinforced plastered and there is an increase in stiffness strength and energy dissipation due to presence of partially reinforced masonry in-fills. P.B Kulkarni, et.al, (2013)[8], studied “Analysis of Masonry Infilled RC Frame with & without Opening Including Soft Storey by using “Equivalent Diagonal Strut Method”.

Symmetrical frame of building (G+5) located in seismic zone III is

considered. With reference to FEMA 273 and ATC 40 the provision of calculation of stiffness of in-filled frames by modeling infill as an equivalent diagonal strut method and the frames were subjected to linear static analysis. The result obtained shows that infill panels increases the stiffness of the structure and while the increase in the opening percentage leads to decrease on the lateral stiffness of in-filled frame. Md. Irfanullah, et.al, (2013)[9], conducted an investigation on the “Seismic Evaluation of RC Framed Buildings with Influence of Masonry Infill Panel”. Behaviour of RC frames and to observe the effect of masonry infill panel, it is modelled as an equivalent diagonal strut using E-TABS. In order to study, six RC framed buildings with brick masonry in-fills were designed with different configurations, subjected to earthquake loading and comparison of results is made between them. The results observed were, providing infill below plinth and in swastika pattern in the ground floor improves earthquake resistant behaviour of the structure when compared to soft storey. And it was concluded that the provision of


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SEISMIC RESPONSEOF MASONRY INFILLED R.C FRAMES infill wall enhances the performance in terms of storey displacement and storey control and increase in lateral stiffness. S.Niruba, et.al, (2014)[10], studied on “Analysis of Masonry Infill in a Multi-Storied Building”. The structural effect of brick infill when it is not considered generally in the design of columns and also in other structural elements. Nonlinear static analyses were performed on the structural models of the building for both bare framed and infilled one. And also it explains about the brick walls have significant in-plane stiffness of the frame against lateral load. And it was concluded that there is a significance of infill in increasing the strength, stiffness and frequency of the entire system and that depends on the position and amount of infilling. And also it was noted that the lateral deflection was reduced significantly in in-filled frame compared to the deflection of the frame without infill. Haroon Rasheed Tamboli, et.al, (2014), [11], studied and analysed “Seismic Analysis of RC

Frame Structure with and without Masonry Infill Walls”. Frames

with three different infill configurations subjected to dynamic loading. The seismic analysis is performed using equivalent lateral force method and equivalent strut method using E-TABS software. The parameters discussed were time period, natural frequency base shear and storey drift. It was revealed that the in-filled frames increases the storey drift and also infill frame increases the strength and stiffness of the structure. Arulmozhi.N, et.al, (2015), [12], made “Analytical Study on Seismic Performance of RC Frames In-filled with Masonry walls”. Frames with in-fills have more strength and rigidity in conditions comparison to the bared frames. Hence the studies about the behavior of 3D-RC frames with or without masonry in-fills are necessary. Kiran Tidke and Sneha Jangave, (2016)[13], studied “Seismic Analysis of Building with and Without Infill Wall”. The effect of masonry infill wall on building is studied. Dynamic analysis of building with different arrangement is carried out. For analysis G+7 R.C. frame building is modelled. The width of strut is calculated by equivalent diagonal strut method. Analysis is carried by SAP2000 software. Base shear, Max storey drift, Displacement is calculated and compared for all models.


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SEISMIC RESPONSEOF MASONRY INFILLED R.C FRAMES Narendra A. Kaple, et.al, (2016)[14], studied “Seismic Analysis of Frame Structure with and without Masonry Infill Walls”. Prepared G+6 R.C.C framed building models on ETABS software and Seismic coefficient method and Response Spectrum analysis has an the building for analysis as per IS 18:2002 and results obtained from the analysis are compared in terms of strength and stiffness for bare frame and infill wall. 1.8 SUMMARY By the thorough review of all the above literatures it was observed that there is a significance increase in the strength, stiffness and the frequency of the infilled system compared to systems without infill. And also it is noted that the provisions of infill walls enhances the performance of the buildings by decrease in the storey displacement and also storey drifts, Therefore in this project we are studying the analysis of the effect of lateral load resisting system for multi storey building with and without infill walls and also the study of parameters like storey displacement, storey drifts, time period and base shear. Table 3 : Summary of Literature Review Sl. No

Researchers

Year

Topics

2007

An Experimental Study On Exhibits Reinforced Concrete higher Partially In-filled Frames strength

Ozgur Anil, et.al 1

2

Santiago et.al

Pujol, 2008

3

J. Dorji and D.P. Thambiratnam

4

Kashif et.al

2009

Mahmud, 2010


Masonry Infill walls: An Effective Alternatives for Seismic Strengthening of Low-Rise Reinforced Concrete Building Modelling and Analysis of Structures Infilled Frame Structure under seismic Loads

Results significantly ultimate

Compared with results from a previous experiment Tip deflection, fundamental period, inter-storey drift ratio and stresses

The Reinforced Concrete Deflection eventually Frame with Brick Masonry decreases Infill due to Lateral Loads

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SEISMIC RESPONSEOF MASONRY INFILLED R.C FRAMES

5

Wackchaure M.R, et.al

2012

Mulgund G.V 6

2012

G.C Manos, et.al 7

2012

P.B Kulkarni, et.al 8

9

2013

Md. et.al

Irfanullah, 2013

S.Niruba, et.al 10

11

Haroon Rasheed Tamboli, et.al

13

14

Kiran Tidke and Sneha Jangave

Narendra Kaple, et.al

The Behaviour of Masonry Assemblages and Masonry Infilled RC Frames Subjected to Combined Vertical and Linear StaticSeismic Analysis of Horizontal Type Masonry In-filled RC Loading Frame with and without Opening Including Open Ground Storey Seismic Evaluation of RC Framed Buildings with Influence of Masonry Infill Panel

Increase in stiffness strength and energy

Increases the stiffness of the structure

Increase stiffness

in

lateral

2014

Analysis of Masonry Infill in a Multi-Storied Building

Lateral deflection was reduced

2014

Seismic Analysis of RC Frame Structure with and without Masonry Infill Walls

Infill frame increases the strength and stiffness of the structure.

2015

Analytical Study on Seismic Performance of RC Frames In-filled with Masonry walls

Frames with in-fills have more strength and rigidity in conditions comparison to the bared frame

Arulmozhi.N, et.al 12

in Earthquake Analysis of Reduction time High Rise Buildings with displacement, period and increases and without In-filled Walls base shear. Comparison is made Seismic Assessment of RC between the results of Frame Buildings with bare frame and with Brick Masonry In-fills. infill effect

2016

A. 2016


Seismic Analysis of Building with and Without Infill Wall Seismic Analysis of Frame Structure with and without Masonry Infill Walls

The effect of masonry infill wall on building is studied Results obtained from the analysis are compared in terms of strength and stiffness for bare frame and infill wall Page 28

SEISMIC RESPONSEOF MASONRY INFILLED R.C FRAMES 1.9 Objectives The seismic analysis of the RC frame structure with and without infill walls will be carried out with the following objectives a. To determine the seismic response of the building with and without infill walls using ETABS 2015. b. To obtain effectiveness of the infill walls which are investigated in terms of reduction of structural responses such as displacements, storey drifts, time period and base shear of the structure.


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SEISMIC RESPONSEOF MASONRY INFILLED R.C FRAMES CHAPTER – 2 METHODS OF ANALYSIS 2.1. Methods of seismic modelling 

Seismic Forward Modelling : Forward numerical modelling of seismic data is the use of geological models of the earth to simulate seismic field experiments. Models can be one, two, or three dimensional and consist of depth horizons and associated P wave velocities, S wave velocities, and densities The most common use of forward modelling is for verification of structural and stratgraphic interpretations. For example, synthetic seismic sections derived from forward modelling can be compared to stacked sections to verify the original interpretation. If needed, the original interpretation or model is altered and the process repeated until a desired correlation between the actual data and modelled results is observed



Seismic modelling with the reflectivity method : This modelling method represents wave propagation in the frequency-wave number domain, and it mainly deals with coefficient matrix computation in the frequency-wave number domain. The modelling theory describes wave behaviour in stratified earth models in a convenient way, where all wave types can be decomposed into up going and down going waves; and waves can be decoupled into P-SV and SH wave types (Kennett, 1983). Reflections, transmissions, conversions of all wave modes, and the corresponding multiples inside sandwiched (thin) layers inserted between two half spaces or a free surface and a half space can be fully modelled. Moreover, modelling in the frequency-wave number domain makes it easy to handle absorptions in an elastic media .



Seismic modelling by finite-difference method :

The finite-difference

method (FDM), one of the most popular methods of numerical solution of partial differential equations, has been widely used in seismic modelling.


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Seismic modelling by A multi symplectic pseudo spectral method : This method takes the multi symplectic structure of the scalar wave equation into account and possesses discrete multi symplectic conservation laws.

2.2 Methods of analysis 2.2.1 Response spectrum analysis A response spectrum is simply a plot of the peak or steady-state response (displacement, velocity or acceleration) of a series of oscillators of varying natural frequency, that are forced into motion by the same base vibration or shock. The resulting plot can then be used to pick off the response of any linear system, given its natural frequency of oscillation. One such use is in assessing the peak response of buildings to earthquakes. The science of strong ground motion may use some values from the ground response spectrum (calculated from recordings of surface ground motion from seismographs) for correlation with seismic damage. If the input used in calculating a response spectrum is steady-state periodic, then the steady-state result is recorded. Damping must be present, or else the response will be infinite. For transient input (such as seismic ground motion), the peak response is reported. Some level of damping is generally assumed, but a value will be obtained even with no damping The main limitation of response spectra is that they are only universally applicable for linear systems. Response spectra can be generated for non-linear systems, but are only applicable to systems with the same non-linearity, although attempts have been made to develop non-linear seismic design spectra with wider structural application. The results of this cannot be directly combined for multi-mode response.

2.2.2 Time history analysis Time-history analysis provides for linear or nonlinear evaluation of dynamic structural response under loading which may vary according to the specified time function


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SEISMIC RESPONSEOF MASONRY INFILLED R.C FRAMES 2.3 Comparison between analysis methods A full time history will give the response of a structure over time during and after the application of a load. To find the full time history of a structure's response, you must solve the structure's equation of motion. Response spectrum analysis is a linear dynamic statistical analysis method which measures the contribution from each natural mode of vibration to indicate the likely maximum seismic response of an essentially elastic structure. Response spectrum analysis provides insight into dynamic behaviour of measuring pseudo spectral acceleration, velocity, or displacement as a function of structural period for a given time history and level of damping. it is practical to envelope response spectra such that a smooth curve represents the peak response for each realization of structural period. Response spectrum analysis is useful for design decision making because it relates structural type selection to dynamic performance. Structures of shorter period experience greater acceleration, whereas those of longer period experience greater displacement. Structural performance objectives should be taken into account during preliminary design and response spectrum analysis.


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SEISMIC RESPONSEOF MASONRY INFILLED R.C FRAMES CHAPTER-3 3.0 METHODOLOGY In the present project, G+10 storey building is considered. The software used in this project is ETABS. This building has been analysed and designed by ETABS and the loads are applied as per IS code requirements i.e. Gravity loads, Lateral loads, Imposed loads, as per IS 456-2000, IS 875, IS 1893(part 1):2002. 3D Analysis has been done for medium soft soil conditions with earthquake zones-5. Equivalent Static analysis is carried out by model analysis to obtain storey displacement, time period and story drift. 3.1 Design Loads (Types of load used) 3.1.1 Dead Loads This load comprises of self-weight of the entire frame, membrane elements. Membrane elements modelled into the structure. Dead loads are considered as per IS 875(part 1):1987. 3.1.2 Imposed Loads Finishes:This load comprises of floor finishes, partitions, wearing coat and water proofing. Wall Load: All the partition walls are 100mm thick. Loads are calculated and applied at appropriate locations as uniformly distributed load on the beams. The Super Imposed Load or Otherwise Live Load Assessed Based on the Occupancy Classifications as per IS- 875 (part 2):1987. 3.1.3 Earthquake Load Earth quake loads are considered as per IS 1893(part 1):2002, in both X and Y directions. The Response Spectrum values are calculated based on the T v/s Sa/g equations as per clause 6.4.5 of IS 1893(part 1):2002. Base shears of the analysis are raised to a factor as per clause no 7.8.2. 3.2 Seismic Analysis Seismic analysis is a subset of structural analysis and is the calculation of the response of a building structure to earthquakes. It is the part of the process of Dept. of civil Engineering CMRIT

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SEISMIC RESPONSEOF MASONRY INFILLED R.C FRAMES structural design, earthquake engineering or structural assessment and retrofit in regions where earthquakes are prevalent. The design of multi-storey structures is governed by lateral load resistance requirements in addition with gravity loads. The magnitude of the lateral force on a structure is not only dependent on the acceleration of the ground but also it depends on the type of the structure. The term lateral loads describes the effect of seismic and wind forces, even though in the recent past it included any horizontal applied forces, this terminology seeks to differentiate lateral loads from the downward acting gravity loads, even though in reality the seismic forces can act in both vertical and horizontal directions. A building has the potential to wave back and forth during an earthquake this is called as fundamental mode and is the lowest frequency of building response most, buildings, however, have higher modes of response, which are uniquely activated during earthquakes the figure just shows the second mode, but there are higher “shimmy” (abnormal vibration).nevertheless, the first and second modes tend to cause the most damage in most cases. Earthquake engineering has developed a lot since the early days, and some of the more complex designs now use special earthquake protective elements either just in the foundation or distributed throughout the structure. Analysing these types of structures requires specialised explicit finite element computer code, which divides time into very small slices and models the actual physics, much like common video games often have “physics engines”. Very large and complex buildings can be modelled in this way. Structural analysis methods can be divided into the followings 3.2.1 Equivalent Static Analysis The equivalent static method of finding lateral forces is also known as the static method or the seismic coefficient method. This method is the simplest one and it requires less computational attempt and is based on formulae given in the code of practice. In all the methods of analysing a multi storey buildings recommended in the code, the structure is treated as discrete system having concentrated masses at floor levels which comprise the weight of columns and walls in any storey should be Dept. of civil Engineering CMRIT

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SEISMIC RESPONSEOF MASONRY INFILLED R.C FRAMES equally distributed to the floors above and below the storey. In addition, the suitable amount of imposed load at this floor is also lumped with it. It is also assumed that the structure flexible and will deflect with respect to the position of foundation; the lumped mass system reduces to the solution of a system of second order differential equations. These equations are formed by distribution of mass and stiffness in a structure, together with its damping characteristics of the ground motion. In seismic coefficient method the maximum base shear is calculated based on the fundamental time period, importance factor, reduction coefficient. Lateral forces are distributed proportional to square of height. R factor is used to allow structure to go into inelastic stage to dissipate energy through yielding. Limitations: 1. The fundamental period of the building, T is greater than or equal to 3.5 times Ts. 2. The ratio of the horizontal dimension at any story to the corresponding dimension at an adjacent storey exceeding. 3. The building has a severe torsional stiffness irregularity in any story. A severe torsional stiffness irregularity exists in a story if the diaphragm above the story under consideration is not flexible and the results of the analysis indicate that the drift along any side of the structure is more than 150% of the average story drift. 4. The building has a severe vertical mass or stiffness irregularity. A severe vertical mass or stiffness irregularity exists when the average drift in any story (except penthouses) exceeds that of the story above or below by more than 150%. Time History Analysis Time-history analysis provides for linear or nonlinear evaluation of dynamic structural response under loading which may vary according to the specified time function. Dynamic equilibrium equations, given by K u(t) + C d/dt u(t) + M d2/dt u(t) = r(t), are solved using either modal or direct-integration methods. Initial conditions may be set by continuing the structural state from the end of the previous analysis. Additional notes include: 

Step Size – Direct-integration methods are sensitive to time-step size, which should be decreased until results are not affected. Dept. of civil Engineering CMRIT

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HHT Value – A slightly negative Hilber-Hughes-Taylor alpha value is also advised to damp out higher frequency modes, and to encourage convergence of nonlinear directintegration solutions.



Nonlinearity – Material and geometric nonlinearity, including P-delta and largedisplacement effects, may be simulated during nonlinear direct-integration timehistory analysis.



Links – Link objects capture nonlinear behaviour during modal (FNA) applications. 3.2.1.1 Time Period The approximate fundamental natural period of vibration Ta in seconds, of a moment resisting frame building without brick infill panels may be estimated by the following empirical formula Ta=.075h.75 For RC frame building Ta=.085h.75 For steel frame building. The approximate fundamental natural period of vibration in seconds of all other, buildings including moment resisting frame buildings with brick infill panels may be estimated by the following expression. Ta=0.09h/√� Where, h = Height of building in meters (This excludes the basement storey, where basement walls are connected with the ground floor deck or fitted between the columns. But, it includes the basement storey, when they are not connected). d = Base dimensions of the building at the plinth level, in m, along the considered direction of the lateral force. 3.3 Materials For analysis, G+10 storeys which are located in Zone V are considered. The storey height is 3m in all the floor including the ground Floor. There are 12 bays in X and 7 bays in Y direction. M25 grade concrete and Fe415 structural steel is used. Building is fixed at the base. Following data is used in the analysis of the RC frame building models 

Type of frame: Special RC moment resisting frame fixed at the base



Seismic zone: V



Number of storey:G+10 AND 15



Floor height: 3.0 m


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Depth of Slab: 225mm



Size of beam: (300× 500) mm



Size of column: (450 × 450) mm



Live load on floor: 3 KN/m2



Floor finish: 1.0 KN/m2



Terrace water proofing: 1.5 KN/m2



Materials: M 25 concrete, Fe 415 steel and Brick infill



Thickness of infill wall: 230 mm



Density of concrete: 25 KN/m3



Density of infill: 20 KN/m3



Type of soil: Medium

3.3.1 Defining Material Properties The first step in the program is to define the material properties. Once the grade of the materials is defined the software automatically takes the properties of materials such as density, modulus of elasticity, shear modulus, coefficient of thermal expansion etc. The materials used are concrete and rebar (reinforcing steel bars). The values of grades of steel and concrete to be taken for different type of structural components are as shown in (Table 4) below.

Table 4: Material properties TYPE OFMATERIAL

GRADE OFCONCRETE

GRADE OFSTEEL

BEAM

M25

Fe415

COLUMN

M25

Fe415

SLAB

M25

Fe415


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SEISMIC RESPONSEOF MASONRY INFILLED R.C FRAMES Table 5 : Section properties TYPE OF SECTION

SIZE(MM)

COLUMN

450*450

BEAM

300*500

SLAB

225

3.4 Loads and Load Combinations As the building chosen for the analysis is a Residential building, all the possible loads that a residential building is subjected to are taken into account. The below table 6 deals with loads considered and their respective values. Table 6 : Details of Loads Acting member

Type of load

Location

2kN/m2

Live Slab

Terrace water proofing

Load intensity

Roof

Floor Finish

1kn/m2 1.0kN/m2

3.4.1 Load Combinations Analysis of building is performed as per IS 1893 (part1):2002. Equivalent Static analysis are performed in ETABS 2015.Parameters like Deflection, Storey Drift, Fundamental period of Vibration, Forces in beam and column were studied. All the Load combination used in the analysis are mention below 1.5DL 1.5(DL+LL) 1.2(DL + LL ± EQX) 1.2(DL + LL ± EQY) 1.5(DL ± EQX) 1.5(DL ± EQY) 0.9DL ± 1.5EQX 0.9DL ± 1.5EQY Where, EQX & EQY = are lateral force obtained from static analysis in X and Y direction respectively. Dept. of civil Engineering CMRIT

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SEISMIC RESPONSEOF MASONRY INFILLED R.C FRAMES DL = dead load. LL = live load. EQX = earthquake in X-direction. EQY = earthquake in Y-direction. [16]


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SEISMIC RESPONSEOF MASONRY INFILLED R.C FRAMES CHAPTER – 4 4.0 MODELLING 4.1 General ETABS is a computer program made specifically for building systems. The concept of this program was introduced more than 35 years ago by R. W. Clough. The ETABS provides good automation and specialized options to make the process of model creation, analysis, and design with fast and convenience. The ETABS provides tools for laying out floor framing, frames, columns and walls in either concrete or in steel, as well as techniques for quickly generating gravity and lateral loads. The Seismic loads are generated automatically according to the requirements of the selected building codes in software. All of these modelling and analysis options are completely integrated with a wide range of steel and concrete design features. 4.2 Basis Procedure for Modelling Following steps are provided for basic modelling, analysis and design process: 

Set the units



Open a file from menu bar



Define grid data



Define storey data



Define structural properties



Draw structural objects



Assign properties



Define load cases



Assign loads



View the model



Analyse the model



Check the model



Extract the results



Save model


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SEISMIC RESPONSEOF MASONRY INFILLED R.C FRAMES 4.2.1 ETABS window The ETABS working window is as shown in figure 6 below. It includes display title bar, main title bar, menu bar, tool bar and current units.

Fig.6 : ETABS window

4.2.2 Grid system The grid system should be selected by clicking the File menu > New model command. The form of window shown in figure is displayed. After that we have to click No button for further procedure.

Fig.7 :New model initialization


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Fig 8 : Grid system and storey data definition form The plan and the elevation data of the building should be given by using above window. Suppose if the structure having uniform dimensions in both X, Y and Z directions, then enter the values in the edit boxes. Otherwise we have to use custom grid spacing command. After choosing this option, click the edit storey data button and enter the values in the template as shown in (Fig 8) 4.2.3 Defining properties For this Define menu is used, which includes material properties, frame section properties, wall/slab sections, load cases and load combinations as shown in (Fig 9,10,11, 12,13). We have to define the properties here; afterwards we need to assign the properties by using assign menu.

Fig.9 Defining material properties of steel


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Fig 10 : Defining material properties of concrete

Fig 11 :Defining cross section of column


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Fig 12: Defining cross section of beams

Fig 13: Defining material properties of masonry


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SEISMIC RESPONSEOF MASONRY INFILLED R.C FRAMES 4.2.4 Draw structural objects Draw menu is used to draw the structural objects like beam, column, wall, slab etc. To draw the structural objects the structure should be in plan view. Then the objects can be drawn as described below. Draw columns  Click on the create columns in region button or  Select draw > draw line objects > create column in region  Click on the grid points where you want the columns and repeat the same Draw beams  Click on the create lines in region button  Select draw > draw line objects > create line in region  Click on the grid line where the beams are to be placed and repeat the same Draw floor  Click on draw area button or  Select draw > draw area objects > draw area command to draw the floor/slab Structural loads In the present study structural loads includes dead, live and earthquake load and these are applied to the model. 4.2.5 To define structural load cases  Click on Define menu > linear static load case command  Type the name of load case in the edit box 

Select the load type from the drop down list



Type a self-weight multiplier i.e. one for dead load and zero for other loads.



If the load type is quake, auto lateral load should be selected from drop down list.


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Fig 14: Defining Load Cases 4.2.6 To assign structural loads Click on add new load button. The defined load cases are required to assign on points/joints, lines/frames, area/shells. First we have to select the object before assigning the load on the objects.

Fig 15 : Defining Load Cases


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Fig 16: Defining Load Cases 4.3 Details of the Selected Building Description In the present study, 10 and 15 storey building is considered for the investigation, the layout of the building is regular, which consisting of assemblage of slab, beam and column elements. Same properties are used for both the cases. i.e. with and without infill walls. Analysis is done by using ETABS 2015 software. Time history analysis is carried out for the earthquake zone V. Model I: Bare frame building.

Fig 17.a: Layout of the Model Dept. of civil Engineering CMRIT

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Fig 17.b : 3D and Plan of view Model

Model II: Building with walls provided.

Fig 18.a : Layout of the Model


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Fig 18.b: 3D and Plan of view Model


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SEISMIC RESPONSEOF MASONRY INFILLED R.C FRAMES CHAPTER – 5 5.0 RESULTS AND DISCUSSION 5.1 General In this project work the comparison of response of RC frame structures with and without infill wall is carried out. Totally 3 models are considered and they are analysed using NON-LINEAR TIME HISTORY ANALYSIS method. The following results like storey displacement, storey drift and time period for zone V are obtained as per IS 1893(part 1):2002 are obtained. 

DISPLACEMENT :

A displacement is scalar that is the shortest distance from the initial to the final position of the body. It quantifies both the distance and direction of an imaginary motion along a straight line from the initial position to the final position of the point. Table No 7 : Displacement STOREY DISPLACEMENTS (m) WITHOUT INFILL

STOREY 10 9 8 7 6 5 4 3 2 1 0

G+10 X 0.02714 0.02614 0.0246 0.02249 0.01983 0.01669 0.01317 0.009387 0.005514 0.001956 0

M1 1576.481Kg/M3 G+10 X 0.0007 0.0006 0.0023 0.0014 0.0012 0.001 0.0008 0.0006 0.0004 0.0001 0


WITH INFILL M2 1707.07Kg/M3 G+10 X 0.0007 0.0007 0.0022 0.0012 0.0011 0.0009 0.0007 0.0005 0.0003 0.0001 0

M1 1844.667Kg/M3 G+10 X 0.0007 0.0007 0.0021 0.0011 0.001 0.0008 0.0006 0.0005 0.0003 0.0001 0

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Fig 19 : Displacement With Respect To Stories The graph is drawn by taking displacement values along x-axis and story along y-axis. From the figure we can understand that the frame without

infill have greater

displacement than frame with infill. Infill having lesser density 1576.48 kg/m3 has displacement lesser than the infill with higher density 1844.667 kg/m3 comparatively. Table No 8 : Displacement

WITHOUT INFILL

STOREY 10 9 8 7 6 5 4 3 2 1 0

G+10 Y 0.01266 0.01215 0.01139 0.01038 0.009119 0.007652 0.006018 0.004273 0.002501 0.0008873 0

STOREY DISPLACEMENTS WITH INFILL M1 M2 1576.481Kg/M3 1707.07Kg/M3 G+10 G+10 Y Y 0.1 0.1 0.1 0.1 0.0173 0.0164 0.0107 0.0098 0.0092 0.0085 0.0078 0.0071 0.0062 0.0057 0.0046 0.0042 0.003 0.0028 0.0013 0.0012 0 0


M1 1844.667Kg/M3 G+10 Y 0.1 0.1 0.0156 0.0089 0.0078 0.0066 0.0052 0.0039 0.0025 0.0011 0

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Fig 20: Displacement With Respect To Stories The graph is drawn by taking displacement values along x-axis and story along y-axis. From the figure we can understand that the frame without infill and with infill have very similar displacements but only in last two stories have higher displacements which may be due to local effects

LATERAL FORCE: Most lateral loads are live loads whose main component is horizontal force acting on the structure. Typical lateral loads would be a wind load against a facade, an earthquake, the earth pressure against a beach front retaining wall or the earth pressure against a basement wall. Table No 9 : Lateral Load

STOREY 10 9 8 7 6 5 4 3 2 1 0

WITHOUT INFILL X 2461.9736 2136.6712 1688.2341 1292.5542 949.6317 659.4664 422.0585 237.4079 105.5146 26.3787 0

LATERAL FORCE(kn) WITH INFILL M1576.481KG/M*3 1707.07KG/M*3 X X 3180.2275 3239.3891 2927.1831 2991.9622 1968.0586 1991.5328 1506.7949 1524.7673 1107.033 1120.2372 768.7729 777.9425 492.0146 497.8832 276.7582 280.0593 123.0037 124.4708 30.7509 31.1177 0 0


1884.667KG/M*3 X 3301.7481 3060.2005 2016.3289 1543.7518 1134.185 787.6285 504.0822 283.5463 126.0206 31.5051 0 Page 52


LATERAL FORCE X-dir 12

storey (m)

10 8 Series1

6

Series2

4

Series3

2

Series4

0 0

1000

2000

3000

4000

lateral force (kn)

Fig :21: Lateral Load With Respect To Stories The graph is drawn by taking lateral load values along x-axis and story along y-axis. From the figure we can understand that the frame without infill has less carrying capacity of lateral loads than the frames with infill. As the density of infill increases the carrying capacity of lateral load increases. Table No 10 :Lateral Load LATERAL FORCE(kn) WITH INFILL

STOREY 10 9 8 7 6 5 4 3 2 1 0

WITHOUT INFILL y 0 0 0 0 0 0 0 0 0 0 0

M1576.481KG/M*3 1707.07KG/M*3 1884.667KG/M*3 y y y 3180.2275 3239.3891 3301.7481 2927.1831 2991.9622 3060.2005 1968.0586 1991.5328 2016.3289 1506.7949 1524.7673 1543.7518 1107.033 1120.2372 1134.185 768.7729 777.9425 787.6285 492.0146 497.8832 504.0822 276.7582 280.0593 283.5463 123.0037 124.4708 126.0206 30.7509 31.1177 31.5051 0 0 0


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storey (m)

LATERAL FORCE Y-dir 12 10 8 6 4 2 0

la Series2 Series3 Series4 0

1000

2000

3000

4000

lateral force (kn)

Fig :22 : Lateral Load With Respect To Stories The graph is drawn by taking lateral load t values along x-axis and story along y-axis. From the figure we can understand that the magnitude of lateral load resisting capacity increases with increase in storey for infilled frames and frames without infill can’t resist any lateral loads in y direction.

STORY SHEAR The factor is defined as the ratio of story shear force when story collapse occurs to the story shear force when total collapse occurs. Table No 13 : Story shear STORY SHEAR (Kn)

STOREY 10 9 8 7 6 5 4 3 2 1 0

WITHOUT INFILL X -0.1153 -0.2344 -0.3468 -0.4497 -0.5406 -0.0673 -0.0679 -0.7213 -0.7468 -0.7559 0

M1576.481KG/M*3 X -3.7001 -7.6053 -8.7781 -9.3722 -9.9023 -10.345 -10.6897 -10.9408 -11.1037 -11.1765 0


WITH INFILL 1707.07KG/M*3 X -4.0928 -8.4097 -9.649 -10.2676 -10.8225 -11.2856 -11.6459 -11.9082 -12.0784 -12.1545 0

1884.667KG/M*3 X 4.5105 9.2649 10.5688 11.2106 11.7895 12.2721 12.6473 12.9203 13.0975 13.1769 0

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STORY SHEAR X-dir 12 10

STOREY (M)

8 Series1

6

Series2

4

Series3

2

Series4

0 -15

-10

-5

0

5

10

15

SHEAR (KN)

Fig :25 : Story shear With Respect To Stories The graph is drawn by taking story shear values along x-axis and story along y-axis. From the figure we can understand that the story shear property of the multistory building will be maximum at the lower story and will be minimum at the top . and as the density increases the story shear value also increases.

Table No 14 : Story shear STORY SHEAR (Kn) WITH INFILL WITHOUT INFILL M1576.481KG/M*3 1707.07KG/M*3 STOREY Y Y Y 10 0 357.091 359.2628 9 0 735.5157 739.7129 8 0 893.5265 888.5636 7 0 996.6079 983.0121 6 0 1085.5022 1064.7198 5 0 1160.1744 1133.34 4 0 1219.4231 1187.7097 3 0 1263.4657 1228.0787 2 0 1292.5361 1254.7194 1 0 1305.4229 1266.5616 0 0 0 0


1884.667KG/M*3 Y -360.4337 -741.8404 -881.7975 -968.2892 -1043.3987 -1106.4562 -1156.3488 -1193.3521 -1217.7661 -1228.6477 0

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STOREY SHEAR Y-dir 12

10

STOREY (M)

8 Series1

6

Series2 Series3

4

Series4

2

0 -1500

-1000

-500

0

500

1000

1500

SHEAR (KN)

Fig :26 : Story shear With Respect To Stories The graph is drawn by taking story shear values along x-axis and story along y-axis. From the figure we can understand that the story shear property of the multistory building will be maximum at the lower story and will be minimum at the top and as the density increases the story shear value also increases.


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CHAPTER 6 CONCLUSION From all the observations of the building with the results of different densities of the infill i.e., displacements, lateral force, story shear etc also on comparing them with the results of frame without infill we can conclude that as the infill is provided with higher density the effect of its resistance to seismic activity will increase with respect to frame without infill. From the literature we were able to understand that masonry is very good in resist lateral earthquake forces, from all of the observations of the building with the results of different densities of the infill i.e., displacements, lateral force, story shear also on comparing them with the results of frame without infill for an asymmetric building we can conclude the following: 

The displacements of the building along both directions is very small but along y

axis it is more which may be due to asymmetry in one axis and internal stresses. Displacement is increasing as number of storey’s increases and also is dependent on displacement as discussed. Hence, density of infill needs to consider in structural design for safe displacement values. 

Lateral forces and its resisting capacity is increasing as density increases. In

symmetric structures in one of the direction lateral force becomes due to eccentricity in center of mass and center of gravity of plan. But in our case even though it is asymmetric the building has very good lateral load capacity in both directions which is advantages in unpredictable earthquake loads. This phenomenon also needs to be studied further. 

Story shear is maximum at the base of building and goes on decreases with increase in number of storeys. The building without infill has zero shear in y-direction gives advantage while designing buildings and when it comes to failure of buildings Dept. of civil Engineering CMRIT

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SEISMIC RESPONSEOF MASONRY INFILLED R.C FRAMES by shear but since the ratio is very high in bottom force it is not desirable and needs to be taken care of during design. Finally it can be concluded that if infills are provided and have a very high density then structure will be able to resist high lateral loads which are predominant during earthquakes also bending moments and shear forces on the beams and columns are also decreased which will lead to reduced cost due to savings in reinforcement. The asymmetric plan if made as studied in the thesis will help to make certain effects of load zero or negligible as seen in the results which is advantageous when it comes to structural design and will also help in reduction of cost. So, for a structure to have earthquake resistance it can concluded that it is desirable to have an asymmetric structure with very good high density infill material which will help in taking earthquake loads and also reduce the overall cost of construction by reduction in reinforcement cost. The only care that should be taken while construction of such structure is we should be able to make sure that the infill and the frame have proper bonding and should behave monolithically with the structure

REFERENCES : 

Anil, Özgür, and Sinan Altin. "An experimental study on reinforced concrete partially infilled frames." Engineering Structures 29.3 (2007): 449-460.



Pujol, Santiago, et al. "Masonry infill walls: an effective alternative for seismic strengthening of low-rise reinforced concrete building structures." 14th World Conference on Earthquake Engineering (Beijing, China, Unknown Month October 12). 2008.



Dorji, Jigme, and David P. Thambiratnam. "Modelling and analysis of infilled frame structures under seismic loads." The Open Construction & Building Technology Journal 3 (2009): 119-126.



Mahmud, Kashif, Md Rashadul Islam, and Md Al-Amin. "Study the Reinforced Concrete Frame with Brick Masonry Infill due to Lateral Loads." International Journal of Civil & Environmental Engineering IJCEE-IJENS 10.04.


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Wakchaure, M. R., and S. P. Ped. "Earthquake analysis of high rise building with and without in filled walls." International Journal of Engineering and Innovative Technology (IJEIT) Volume 2 (2012).



Mulgund, G. V., and A. B. Kulkarni. "Seismic assessment of RC frame buildings with brick masonry infills." International journal of advanced engineering sciences and technologies 2.2 (2011): 140-147.



Kulkarni, P. B., Pooja Raut, and Nikhil Agarwal. "Linear Static Analysis Of Masonry In-Filled RC Frame With And Without Opening Including Open Ground Storey." International Journal of Innovative Research in Science, Engineering and Technology. Vol 2 (2013): 2215-2223.



Irfanullah, Md, Md Irshad Ali, and Vishwanath B. Patil. "Seismic evaluation of RC framed buildings with influence of masonry infill panel." International Journal of Recent Technology and Engineering (IJRTE) 2.4 (2013).



Niruba, S., K. V. Boobalakrishnan, and K. M. Gopalakrishnan. "Analysis of Masonry Infill In A Multi-Storied Building." Analysis 3.3 (2014): 26-31.



Tamboli, Haroon Rasheed, Umesh N. Karadi, and Haroon Rashid Tamboli. "Seismic Analysis of RC Frame Structure with and without Masonry Infill Walls." Indian Journal Of Natural Sciences International Bimonthly ISSN 976 (2012): 0997.



Mehrabi, Armin B., et al. "Experimental evaluation of masonry-infilled RC frames." Journal of Structural engineering 122.3 (1996): 228-237.



Wakchaure, M. R., and S. P. Ped. "Earthquake analysis of high rise building with and without in filled walls." International Journal of Engineering and Innovative Technology (IJEIT) Volume 2 (2012).



Tamboli, Haroon Rasheed, Umesh N. Karadi, and Haroon Rashid Tamboli. "Seismic Analysis of RC Frame Structure with and without Masonry Infill Walls." Indian Journal Of Natural Sciences International Bimonthly ISSN 976 (2012): 0997.


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