standardizing methods of measurement for earthworks and in situ

STANDARDIZING METHODS OF MEASUREMENT FOR EARTHWORKS AND IN SITU CONCRETE WORKS IN SUDANESE CONSTRUCTION INDUSTRY Yassir Daffallah Ahmed1, Elkheir Abbas Obied Alasad2and Yousif Hummaida Ahmed3 [email protected], [email protected] Department of Civil Engineering, Faculty of Engineering, University of Khartoum [email protected]

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‫ســت َ ْخـلـَص‬ ْ ‫ُمـ‬ ‫ ويرجع ذلك إلى ضعف طرق‬.(BOQ( ‫ تشهد العديد من مشاريع صناعة التشييد المزيد من المطالبات والنزاعات المرتبطة بجدول الكميات‬، ‫في السودان‬ ‫تهدف هذه الورقة إلى معالجة مستوى المعرفة بطرق القياس‬. ‫) والذي ينتج عنه زيادة التكلفة والجدول الزمنى المخطط لهما‬SMM( ‫القياس المعيارية‬ ‫ تمت مراجعة عدد من‬، ‫ لتحقيق هذه األهداف‬.‫المعيارية العالمية وتوحيد وصياغة مقترح لطريقة القياس لألعمال الحفريات واألعمال الخرسانية في السودان‬ ‫أجريت المقابالت و االستبيان مع خمسة وخمسين من المشاركين‬. ‫طرق القياس المعيارية العالمية و استخدمت كل من المقابالت واإلستبيانات لجمع البيانات‬ ‫ أظهرت النتائج وجود ضعف في اإللمام بطرق القياس المعيارية العالمية وتم تصنيف‬.‫(المقاولين وأصحاب العمل واإلستشاريين وغيرهم) في السودان‬ ‫وأعقب هذه االستنتاجات توصيات لتوحيد طريقة القياس ألعمال‬. ‫العناصر الخاصة بقياس أعمال الحفريات و الخرسانة في الموقع وتنظيمها وفقا للنتائج‬ .‫أخرى‬

ABSTRACT In the Sudan, several construction industry projects are experiencing more claims and disputes related to bills of quantities. This is due to lack of standard method of measurement (SMM) that results in exceeding the initially estimated cost and schedule. This paper aims to addresses level of knowledge about the international SMM and Standardize and formulate a proposal for a method of measurement for earthwork and In situ concrete works in the Sudan. To achieve these objectives international standard methods of measurement were reviewed. Interviews and questionnaire survey tools were used for data collection. Interviews and questionnaire survey were conducted with fifty five participants (contractors, owners, consultants and others) in the SCI. The results show there is shortage in SMM awareness. Items for earthworks and In situ concrete was categorized, organized and proposed according to the results. These conclusions were followed by recommendations to standardize method of measurement for other works. Keywords: Earthworks; In situ concrete works; standardization; Standard Method of Measurement in Sudan; Bill of Quantities.

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Conference of Civil Engineering – Dec. 2018 out detailed rules for the measurement of commonly occurring works. It also provides good guidelines as to what a tendering contractor is to allow for against each measured item. The SMM can be localized to fit with local custom and practice of performing a certain construction work type in CI [3].

1. Introduction The International Organization for Standardization (ISO) describes a standard as ‘a document that provides requirements, specifications, guidelines or characteristics that can be used consistently to ensure that materials, products, processes and services are fit for their purpose[1].The construction industry (CI) is a generic term for a service industry that forms part of any nation’s economy. It is carry many duties including planning, design, construction, alteration, refurbishment, maintenance, repair and demolition of structures [2]. Construction industry (CI) is one of the important sectors that contribute to the growth of economic sector. To ensure the CI growth, there is an urgent need within the industry to adopt standardization in construction information and documentation[3]. For every pound that we spent in the CI there is a waste a pound due to a lack of standards and standardization [4]. To achieve good value for money there are two key objectives. These include ensuring that accurate budgets are prepared before work commences and correct price is eventually paid for the completed work [5]. The need for standards is not disputed[6]. Standardization of CI aims to eliminate wastage, cost overruns, mismanagement and disputes[7, 8] .

Royal Institution of Chartered Surveyors (RICS), define Standard Method of Measurement (SMM) as a document that provides uniform basis for measuring building works and civil engineering works. The purpose is to ensure that a BOQ produced will fully describe and accurately represent the quantity and quality of the works to be carried out[18]. The SMM will enable the CI to move towards greater uniformity in producing information on construction projects that easily understood by everyone[19].One of the main reasons of failures of the projects in the CI are non‐ standard practice of preparing the BOQ and its costing. This practice may be due to use of different method of measuring quantities, as well as , the degree of accuracy of measuring[20]. The Sudanese CI needs effective methods for gathering and utilizing performance information on industry, company, and individual project levels [21]. It also faces many problems and obstacles, such as: inaccurate estimation of the time, defects during the process of construction, cost overrun, `etc. [22].

Quantity surveyors (QSs) are professional who provide services include the preparation of preliminary estimates, feasibility studies, cost plans, schedules, and bills of quantities (BOQ). They ensure that the resources of the construction industry are utilized to the best advantage of society by providing the financial management for projects and a cost consultancy service to the client and designer during the whole construction process [9] [10]. The BOQ is a uniform document for contractors to estimate or price the works precisely on the same basis, thus allowing for the fairest bidding[11].

Most of the construction companies in Sudan face many of constraints that are, negatively, affect the performance of their projects. Such constraints have direct effect on the cost and time factors of the project[23]. The lack of SMM is a factor that affects the development of the CI in Sudan[24].Therefore, there is a need to raise awareness of SMM in the Sudanese CI. There is negligence of documentation process. That leads to losses in valuable information; hence loss of money to contractors. There is a huge need to raise awareness on the significance of adapting standardization measurement methods in Sudanese CI. Standardization will helps in achieving consistency in management and operations thus indirectly reduce the conflict among the key players on CI works.

A BOQ is an important link in the cost estimation process and construction work planning. The correctness of determining work amount in a BOQ affects the accuracy of costing construction works in budget estimates. It also affect the quality of work implementation schedules [12]. The BOQ is a well-established means of enabling the financial control and management of Construction works. The key to the success of the use of BOQ is a clear understanding by all parties to the contract of what is included, or excluded, in the measurement.

There are two ways to avoid claims due to construction works measurement. One is to ensure that BOQ is measured in accordance with the SMM applicable. Second is to measure the items as accurately as possible at tender stage on the information available. [17].

That gives rise to the requirement for clearly defined standard methods of measurement (SMM). For example International Principles of Measurement (POMI), Standard Method of measurement for building works (SMM7)[13], Civil Engineering Standard Methods of Measurement (CESMM4)[14] and New Rules of Measurement for building Works (NRM)[15]. SMM can be described as a document that contains a standard format for the presentation of measured work. It also contains set of rules that are mutually known and accepted [16]. Also according to Ref. [17], It should set

The research paper aims to design a SMM for earthwork to be adopted in the Sudanese CI. Also the objective is to create a method of measurement for earthwork that compatible with local construction techniques and terminology. It also is based on local estimating methods and constructs a SMM that is consistent and easy to understand.

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Conference of Civil Engineering – Dec. 2018 By assuming random sampling technique, a total number of 55 questionnaires were distributed among professional experts in Sudanese CI. Also, based on the respondents; it was decided to that interviews will be conducted with sample of professionals with more experiences. The respondents were asked to rank the factors affecting earthwork measurement according to the degree of agreement on a LIKERT Scale [26] for analyzing data by ordinal scale; an Agreement Index (AI) calculated by equation (1) as follows.

2. Methods and Materials 2.1 Research method This paper has adopted six major steps as research method adapted from [25] shown in Figure 1.

1.Review metheods of describtion and measuring earthwork in different SMM.

2.Preliminary survey of local earthwork measurement practice identified by Interviews

4.Data Collection and Analyzied.

3.A questionnaire was Designed & Distribuated Among ( Contractors, Clients and Consultants)

5.Draft SMM for earthwork.

𝐴𝑔𝑟𝑒𝑒𝑚𝑒𝑛𝑡 𝐼𝑛𝑑𝑒𝑥(𝐴𝐼) =

3𝑛1 +2𝑛2 +𝑛3 3×(𝑛1 +𝑛2 +𝑛3 )

(1)

Where: n1 Number of respondents who answered, “agree”; n2 :Number of respondents who answered, “neither agree nor disagree”; n3 :Number of respondents who answered, “Disagree” .

6.Conclution and Recommendations.

3. Results and Discussion The following analysis is based on the questionnaire survey response. Positive responses received from 31 respondents for earthworks and 27 respondents for in situ concrete; representing 56% and 50% response rate respectively. According to the designed questionnaire in Section (2.2) the results were analyzed and discussed.

Figure 1: Research methodology chart 2.2 Questionnaire design To achieve the objective of this paper, professionals in the Sudanese construction industry were invited to participate in a questionnaire survey. The questionnaire was divided into four primary sections such as (I) general information, and (II) questions about awareness of SMM, (III) questions about the effect of SMM on construction management , (IV) questions about the earthwork and in situ concrete methods of measurement in SCI which include other secondary sections. These are description of work, units of measurement and rules of measurement.

3.1 Proposal for Sudanese Standard Method of Measurement (Earthwork Class) Items for earthwork are categorized and organized and a draft earthwork SMM has is finally developed in Table 1 based on highest Agreement Indices. 3.2 Proposal for Sudanese Standard Method of Measurement (In situ concrete works): SMM for buildings In situ concrete shown in table 2 including: Supplying, Placing, Formwork and reinforcement.

2.3 Data collection and analysis

Table 1: Earthwork Method of Measurement Item Preliminary Site work 1. Site Clearance

Level one

Level two

2. Removing trees

1.General 2.Special 1.Girth stated

Job nr

3. Removing surface water

1.General

Job

Excavation 4.General Excavation

1.Bulk excavation

Level three

1.Filling material stated

m3

1. This work is deemed to include: grubbing up roots, disposal off site of all material arising, and filling voids.

1.Depth stated

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Measurement rules

2 5.Foundation Excavation 6. Other Excavation

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1.Strip m 2.Isolated m3 3.Raft m3 1.Removing Silt job 2.Dredging m3 3.Hazardous Materials job 4.Breaking and Exploding job 5.Services Lines m 6.Wells m

1.Soil type stated

1.No allowance for bulking 2. Rock less than 1 m3 not measured separately. 3. No allowance for working space. 4. Excavation includes double handling.

1.Ground water

1. Depth level stated.

Excavation Ancillaries 7. Disposal of materials.

job

1. Clean 2. Polluted

8. Excavation Support.

2. Excavated material

m3

1.Timber supports 2. Metal supports 3.Others stated

m2 m2

1.Soil type stated

1.Desposal distance 1.Left in

1.Depth stated 2.temporary

1. Disposal Distance must be stated. 2. Excavation Sides are Vertical unless stated.

Filling 9.Obtained from m3 excavated materials

1.Soil type stated

1. Filling should include Compaction. 2. Layers Thickness should be stated.

compaction Method

10.Imported filling

m3

1. Mechanical

11.Soil

m3

2.Manual

1. Stabilizing Method

improvement

Table 2: In situ Concrete works Method of Measurement Item Concrete Supplying 1.Concrete Supplying m3 Compressive Strength. (MPa) 15 25 30 35 40 Concrete placing 2.Plain concrete

3.Reinforced concrete

m2

Level one

Level two

Level three

Maximum aggregate size (mm) 10 20 40

Aggregate type 1.Crushed 2.Uncrushed

Type of cement stated

1.Thickness ( mm) Not exceeding 150 Other stated 1. Foundations. Strip Isolated Raft

1. Poured against earth. 2. Other stated. 1.Dimensions stated (length ×width× thickness)

m2 nr m3

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Measurement rules 1. Reinforcement and other metal section volume not deducted. 2. All voids should be deducted.

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2.Columns 3.Beams

Formwork 4.Smooth finish 5.Rough finish

Reinforcement 7. Supply & Bending 8. Fixing

nr m

4.Stairs 5.Slabs 6.Walls

Job m2 m2

1. Foundation. Strip Isolated Raft 2.Columns 3.Beams 4.Stairs 5.Slabs 6.Walls

m2 nr m nr m Job m2 m2

1.Mild steel bars t 2. High yield steel bar t 1. Foundation. Strip m2 Isolated nr Raft m2 2.Columns nr 3.Beams m 4.Stairs Job 5.Slabs m2 6.Walls m2

Cross-section: 1. 250*500 mm 2. 300*600 mm 3.others stated Number of flight Thickness: 1.less than 200mm 2. 200- 300 mm 3. Others stated

1. Horizontal 2. Sloping 3. Vertical 4.Curved 5.Other stated

4.

4.1 Conclusion SMM was concluded for earthwork and in situ concrete as in table 1 and 2 respectively. From result, conclusion can be summaries as follow:

5.

6.

4.1.1 Earthworks 1. There is a lack of awareness about international SMM. Also there is no any SMM adopting in SCI. 2. There is an immense need for adopting SMM in SCI. 3. The most desired effects due adopting SMM are:

• •

7.

Facilitate accurate cost estimating for projects. Reduce the claims and disputes due to ambiguous descriptions. Provide proper time schedule for projects.

8. 9.

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1. Columns integral with a wall shall be measured as part of the wall. 2. Beams integral with a slab shall be measured as part of the slab.

1. The area of formwork measured shall include voids & projections. 2. Temporary support during casting should be included in formwork. 3. Formwork not measured for plain concrete unless stated. 4. Formwork to upper surfaces of concrete shall be measured to surfaces inclined at an angle exceeding 15° to the horizontal.

1. Nominal size stated.

4. Conclusion and Recommendations

•

Locations stated : ( e.g. 1st, 2nd,3rd)

1. Straight. 2. Bent. 3. Curved. 4. Links.

1. The weight of bar reinforcement shall be the net weight without addition for rolling margin, supports, spacers or tying wire. 2. Voids Reinforcement should be included. 3. The Weight of overlaps and losses should not be measured.

The most important information should be stated in excavation works are: Purpose of excavation, type of soil and excavation depth. The most important information should be stated in excavation ancillaries works are: Method of disposal of excavated material and support type for excavation sides. The most important information should be stated in filling works are: Purpose of filling, type of soil and method of compaction. The most important information should be stated in filling ancillaries works are: Method of soil improvement and Method of surface preparing and trimming. The common units of measurement for earthwork used in SCI was identified and tabulated. The most important measurement rules should be stated in excavation works are as follow: • No allowance for bulking. • Excavation includes working space. • Rock less than 1 m3 not measured separately.

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• Excavation includes double handling. 10. The most important measurement rules should be stated in excavation ancillaries are: Disposal distance must be stated. Excavation sides are vertical unless stated. 11. The most important measurement rules should be stated in filling are: Layers Thickness should be stated. Filling should include Compaction.

•

Temporary support during casting should be included in formwork. • Formwork not measure for plain concrete. • Formwork to upper surfaces measured to inclined if exceeding 15° to the horizontal. 12. The most important measurement rules should be stated in concrete reinforcement are: • The weight of bar reinforcement shall be the net weight without addition for rolling margin, supports, spacers or tying wire. • Voids reinforcement should be included. • The weight of overlaps and losses should not measure. 13. The common use sections as follow: • Columns & beams (250*500 -300*600) • Slabs &walls (less than 200 – (200 – 300))

4.1.2 In situ Concrete works From results of the survey we conclude that: 1. There is lack of knowledge about international SMM. 2. There is no SMM used in SCI. 3. There are huge needs for standardizing method of measurement for in situ concrete and civil engineering works in Sudanese CI. 4. The greatest effects of not using SMM are: • Increasing in cost and time due to claims and disputes. • Non fairness in tendering price. • Increasing risk allocation for contractors. 5. The most important descriptions should be stated in concrete supplying are: • Compressive strength • Type and size of aggregates • Type of cement 6. The most important descriptions should be stated in concrete placing are: • Type of concrete. • Type of concrete element. • Walls and slabs thickness. • Beams and columns sections. • Location of concrete element. 7. The most important descriptions should be stated in concrete formworks are: • Type of formwork. • Position of element. • Shape of formwork. 8. The most important descriptions should be stated in concrete reinforcement are: • Type of and size of reinforcement. • Shape of reinforcement. 9. The units of measurement should be stated for concrete supplying, placing, formwork, reinforcement according to Tables 2. 10. The most important measurement rules should be stated in concrete supplying and placing are: • Beams integral with slabs shall be measure as part of slab. • Columns integral with walls shall be measure as part of the walls. • Reinforcement and other metal sections volume not deducted. • All voids shall be deducted. 11. The most important measurement rules should be stated in concrete supplying form work are:

4.2 Recommendation It is recommended to do researches in other construction works not carried here (e.g., precast concrete works, pre-stress concrete works, masonry works and finishes works, etc

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