Pembangunan Rumah Contoh Bambu untuk

Seminar Nasional Teknologi Tepat Guna Penanganan Sarana Prasarana di Indonesia

The Construction of Two Storey Bamboo House Model for Increasing The Utilization of Bamboo as an Environmental Friendly Building Material

Inggar Septhia Irawati*, Morisco*, Suprapto Siswosukarto* *The Lecturer of Civil and Environment Engineering Department, Engineering Faculty, Gadjah Mada University

Abstract Nowadays, flood and landslide often happen in Indonesia due to forest destruction. Timber substituting material to prevent worse forest condition is needed. Bamboo is potential material for wood replacement. Unfortunately, it is difficult to promote bamboo as timber substituting material. Strong bamboo house using bolt and filler connection system has not been introduced well. The project aims to introduce and enhance society’s knowledge about simple method for building two storey bamboo house and increase bamboo usage as construction material. The project was the second year project funded by Hi-Link Project GMU. Further, the project also involved community in apprenticeship activity. Design process has been conducted before building bamboo house, based Indonesia timber design standard. The first and second floor area are 35 m2 and 28.75 m2 respectively. Wulung bamboo was used as structural frame. Lamination bamboo was used as floor, wall, door and window as well as their frame. Load calculated included self weight, life, wind and earthquake. Earthquake load was assigned from the spectrum response graphic, the third area, hard soil of Indonesia building earthquake resistance design standard. Building process was conducted by team from Gadjah Mada University involving Sahabat Bambu, Sanggar Cerdas and the society from Padukan village, Pakem, Sleman Yogyakarta. Building method of the two stairs bamboo house model differed from it of the first stairs bamboo house model. In the case of two stairs bamboo house, structure was built from bottom structure and continued to upper structure. In the case of the first one, frame structure was installed before it was build up together. Average construction cost was Rp. 985,000.-/m2. The cost can be reduced if the skill workers were employed in the construction process. Keywords : Two storey bamboo house, Wulung bamboo, bolt and filler connection syste m

1.

INTRODUCTION

Nowadays, the Indonesia forest condition is getting worse due to over exploitation. It triggers a bigger flood and landslide disaster from year to year. A lot of house was damaged and so many people died. The forest restoration is needed to reduce the disaster and to safe our life. Considering that timber is frequently used as furniture and construction material, it is difficult to reduce or to stop a forest destruction if there is no material can substitute the usage of timber. Bamboo is a potential material for timber substituting in construction fields. The bamboo tensile stress is a high and similar to the steel tensile stress. Due to circular shape, the inertia moment of bamboo is high. The existence of nodes can reduce the local buckling of the bamboo bar. Bamboo is light and ductile so the structure made of bamboo will have a high earthquake resistance

Yogyakarta, 12 April 2008

(Janssen, 1981). A bamboo tensile stress can achieved 2 times of steel tensile stress (Morisco, 1999). Unfortunately, it is difficult to promote bamboo as timber substituting material. The bamboo usage as construction material faces some obstacle with respect to its resistance towards insect attack as well as its connection system. Morisco (1999) proposed preservation method called Boucherie – Morisco. He also has developed connection using bolt and filler to improve its strength since 1995. However, bolt and filler connection system has not been introduced well. The project aims to introduce and enhance society’s knowledge about simple method for building two storey bamboo house and increase bamboo usage as construction material. The project was the second year project funded by HiLink Project GMU. In the first year project, a one

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storey bamboo house model has been built. Comparing to the first project, it can show that bamboo can also be applied for structural purpose for a more complex structure. Further, the project also involved community in apprenticeship activity.

2.

ARCHITECTURAL DESIGN

(a)

Architectural design of a two storey bamboo house can be seen in Figure 1 – Figure 4. Figure 1 illustrates the font view and the back view of the bamboo house. Figure 2 shows the first and the second floor plan. Figure 3 and Figure 4 depicts the cross section and the longitudinal section of house respectively.

(b)

Figure 1. (a) Front view of bamboo house; (b) Back view of bamboo house

(a)

(b)

Figure 2. (a) The first floor plane; (b) The second floor plane


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Figure 3. The cross section of bamboo house

Figure 4. The longitudinal section of bamboo house


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3.

STRUCTURAL ANALYSIS

Structural analysis has been conducted using SAP 2000 version 10.0.1. Structure is modeled as space frame which frame section is defined using self-designer section. Load calculated involved dead load, live load, wind and earthquake. Earthquake load was assigned from the spectrum response graphic, the third area, hard soil of Indonesia building earthquake resistance design standard (2002). Bamboo house was designed as full elastic house in which earthquake reduction factor R is 1.6. Interest factor of a bamboo house is 0.8. Earthquake analysis has been conducted using dynamic response analysis with response spectrum analysis method. The loads applied were combined based on timber Indonesia standard (2002) as follows: 1. Combination 1 = 1.4 dead loads 2. Combination 2 = 1.2 dead loads + 1.6 live loads + 0.5 roof live loads

3. Combination 3 = 1.2 dead loads + 1.6 roof live loads + 0.8 wind loads 4. Combination 4 = 1.2 dead loads + 1.6 roof live loads + 0.5 live loads 5. Combination 5 = 1.2 dead loads + 1.3 wind loads + 0.5 roof live loads + 0.5 live loads 6. Combination 6 = 1.2 dead loads + 1 earthquake loads + 0.5 live loads 7. Combination 7 = 0.9 dead loads + 1.3 wind loads 8. Combination 8 = 0.9 dead loads + 1 earthquake loads The structural analysis result shows that the bamboo house natural period is 0.63 second. A bending moment, an axial forces as well as an shear forces of the bamboo house element is depicted in the Table 1. Figure 5 illustrates the element number written in the Table 1.

(b)

(d)

(c)

(e)

(a) (f)

Figure 5. Frame section of frame element: (a) bamboo frame; (b) frame element number 1; (c) frame element number 2; (d) frame element number 3; (e) frame element number 4; frame element number 5


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Table 1. Axial forces, bending moments, shear forces of the bamboo frame element No. Comb

Element 1

Element 2

Element 3

Element 4

Element 5

1 2 3 4 5 6 7 8 1 2 3

P Kgf -858.18 -2553.77 -1027.45 -1410.2 -1611.72 -1584.96 -834.3 -821.6 374.39 278.68 440.61

M3 Kgf-m 21.65 -310.63 39.55 -42.97 -114.81 102.32 -38.37 -30.63 -213.69 -1147.59 -270.33

V2 Kgf 10.12 -136.47 40.45 -19.41 -88.83 -48.64 -50.64 -14.53 252.18 1449.75 247.95

4 5 6 7 8 1 2 3 4 5 6 7

432.77 307.28 269.83 210.61 231.36 -405.86 -412.73 -364.66 -539.92 -126.97 -489.1 23.6

-492.58 -613.31 -574.03 -264.5 -241.22 -15.28 -12.25 -22.01 -19.89 18.33 -16.37 14.85

8 1 2 3 4 5 6 7 8 1 2 3

-409.1 55.62 -107.38 40.87 -132.86 181.13 -247.39 227.39 -214.04 -626.67 -486.64 -621.89

4 5 6 7 8

-754.41 -294.87 -580.5 -120.88 -543.28

M2 Kgf-m 1 9.47 -0.67 3.09 3.35 50.52 -0.68 47.84 -4.54 -4.47 -9.7

V3 Kgf 2.85E-09 2.85E-08 1.90E-09 8.12E-09 4.57E-09 -101.65 2.73E-09 -96.66 13.41 13.33 28.28

602.35 652.22 640.72 212.51 -203.67 13.54 10.38 19.87 16.71 16.08 14.55 12.26

-6.18 -10.23 -9.78 -8.57 -8.32 -2.07 1.76 -2.84 -2.71 -2.01 4.43 -1.36

18.3 29.62 -26.95 24.69 -22.45 -1.62 -1.43 -2.14 -2.14 -1.47 -3.07 -0.93

13.35 7.74 13.35 -29.54 26.71 -22.92 -16.71 -16.65 -16.04 -3.53 8.09 -3.4

11.79 23.48 38.99 92.85 80.86 58.49 44.64 34.51 40.31 -3.24 -7.59 -3.07

3.93 -2.97 -2.24 -5.29 -3.83 -4.75 -4.96 -3.88 -4.79 -0.32 -4.94 0.52

-2.69 5.62 4.22 11.33 7.12 11.33 13.44 9.72 12.83 0.13 3.04 -0.32

-5.43 3.5 -5.13 1.04 -3.1

-4.65 -4.17 -5.02 -1.89 -2.26

-1.32 -1.09 8.5 0.34 -7.93

0.69 0.86 -0.33 -7.28E-03 -0.26

Based on Table 1, the maximum internal forces of the designed two storey bamboo house model are defined by loads combination between dead loads and live loads.


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4.

STRUCTURAL DESIGN RESULT

Structural analysis output data was used to design structural element. It was carried out based on Indonesia timber construction design standard (2002). Design result shows that the minimal diameter bamboo used for all structural members was 8 cm, diameter bolt used in frame structure was ½”.

Further, the bamboo used in the project was preserved bamboo from Sahabat Bambu. The product of bamboo lamination developed by Morisco also was used. Window, frame as well as their frame used was made of split Petung bamboo lamination made in Forestry Laboratory GMU. Wall board and floor board was made of flat Petung bamboo lamination.

(a)

(b)

Figure 6. (a) Laminated bamboo for window; (b) laminated bamboo wall

5.

CONSTRUCTION PROCESS

Because the two stairs bamboo house is weight, construction process of two stairs bamboo house is different from it of one stair bamboo house (the first year project). In the case of a two stairs bamboo house, structure was constructed from bottom structure and continued to upper structure. In the case of the first one, frame

Figure 10. Erecting column


structure was installed before it was build up together. The sequence of building bamboo house can be seen in Figure 7 – Figure 19. The building process located in Padukan village, Pakem involved Sahabat Bambu, Sanggar Cerdas, society in Padukan Village in apprenticeship activity.

Figure 11. Erecting beam

Figure 12. Erecting bracing

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Figure 13. Erecting purlin

Figure 16. Erecting stair

Figure 14. Erecting roof

Figure 15. Bamboo frame has been finished

Figure 17. Erecting floor

Figure 18. Erecting wall

Figure 19. Two stairs bamboo house

Connection system used is bolt and mortar filler bamboo connection system. In this


project, filler was injected after bamboo frame has been finished to be installed.

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6.

DETAIL JOINT Detail joint A, B, C as well as D can be seen in figures bellow. C

A B

D

Figure 20. Cross section of bamboo frame

Figure 21. Detail joint A

Figure 23. Detail joint C Figure 22. Detail joint B


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Figure 24. Detail joint D

Detail joint between main beam and floor beam can be seen in Figure 25.

Figure 25. Detail joint between main beam and floor beam

7.

CONSTRUCTION COST

The cost for two storey bamboo house model construction is Rp 985.000,-/m2. The cost allocation can be seen in Figure 26. It can be reduced by following bellow: 1. Employing skill worker. The project was apprenticeship activity so the worker used does not have some experience to construct bamboo house.


2. Producing laminated bamboo in the mass scale. In the project, laminated bamboo used was produced in the Forestry Laboratory GMU. If it has been produced in the mass scale (factory scale), the operational cost to product it will be reduced

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Operational PC Sand Bolt and steel Bamboo Laminated bamboo Salary Miscellaneous Finishing Figure 26. The cost allocation of two storey bamboo house construction

8.

CONCLUSION

Based on the implementation of the project, some conclusion can be made as follows: 1. The maximum internal forced used for designing are defined by loads combination between dead loads and live loads. 2. Due to weight, building process of two stairs bamboo house is different from building process of one stair bamboo house. In the case of two stairs bamboo house, structure was built from bottom structure and continued to upper structure. In the case of the first one, frame structure was installed before it was build up together. 3. The cost for two storey bamboo house model construction is Rp 985.000,-/m2. It can be reduced by employing skill worker and producing laminated bamboo in the mass scale. 4. Involving the community from Sahabat Bambu, Sanggar Cerdas as well as the society from Padukan village, Pakem, the aim of the project that is to introduce the building process of two stairs bamboo house can be achieved. Furthermore, it is hope that he utilization of bamboo as construction material can be increased.


ACKNOWLEDGEMENTS The authors are very thankful to: 1. The management of Hi-Link project for providing financial support for this project. 2. Society of Padukan village for providing location to the two stairs of bamboo house building. 3. Sahabat Bambu and Sanggar Cerdas for the collaboration. 4. Bayu Satrio Putra for the assistance.

REFERENCES Badan Standarisasi Nasional, 2002, Standard Perencanaan Ketahanan Gempa untuk Struktur Bangunan (SNI 03-1726-2002), Jakarta Departermen Pekerjaan Umum, 1987, Pedoman Perencanaan Pembebanan untuk Rumah dan Gedung (SKBI-1.3.53.1987), Yayasan Badan Penerbit PU, Jakarta Janssen, J.J.A., 1981, Mechanical Properties of Bamboo, Kluwer Academic Publisher, Netherland. Morisco, 1999, Rekayasa Bambu, Nafiri Offset, Yogyakarta. Morisco, Suprapto, and Irawati, I.S., Development of Bamboo Technology for Producing Environmental Friendly Building Material, Final Report Hi-Link Project Research 2006, VI, page 1-10.

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