PERFORMANCE OF COMPOSITE SHEAR WALL PANEL OF LVL AND GRC BOARD Maryoko Hadi 1, Rudi Setiadji 2, Anita Firmanti 3, Bambang Subiyanto 4, Kohei Komatsu 5 ABSTRACT: The low-cost housing for the people is the main program of Indonesian government. In addition these low-cost homes it must be meet the standards of healthy house and earthquake resistant. In this study, an experiment on composite shear walls has been carried out to determine structural reliability; this is necessary information for practitioners when constructing the earthquake-resistant houses. Analytical and experimental approaches have also been conducted, to establish an appropriate method to estimate the performance of this kind of structure that can be used in the future. Analytical calculation and the test of composite shear wall material of Hevea brasiliensis-paraserianthes Falcataria Laminated Veneer Lumber (LVL) as a frame member and sheathed by 9 mm thick of Glass fiber Reinforced Concrete (GRC) panel, fastened by nail has been carried out. The structural system consisting of wood and cement-based building materials, shows sufficient resistance to earthquake, and so the shear wall panel can be used as a structural element in pre-fabricated houses and earthquakeresistant residential buildings. KEYWORDS: Composite shear wall, earthquake-resistant, LVL, GRC. 1. INTRODUCTION The Housing privation for low-income people run on, to escalate year by year, so that needed a house design that conform to the requirements of its withstand to the earthquake, healthy, simple and instantaneous in the construction process with a low cost of construction. The design standard is required with an area of 36 m 2 house (T.36), with a module size 3 X 3 m, so for T.36 is 6 X 6 m 2. The structure types are not restricted to a particular type of structure but it must be a system of earthquake-resistant structures. The T.36 house plans can be seen in Figure 1. These activities inquire into design house made of a wooden base material and fiber cement board that utilizes the wall as a structural element with a prefabricated modular system for structural parts. With the result that the construction accelerated and simple. on the sites will be 1 Research Institute for Human Settlements, Ministry of Public Works, Jl. Panyawungan, Cileunyi Wetan, Kab. Bandung 40939, Indonesia. Email: maryokohadi@puskim.pu.go.id 2 Research Institute for Human Settlements, Ministry of Public Works, Jl. Panyawungan, Cileunyi Wetan, Kab. Bandung 40939, Indonesia. 3 Research Institute for Human Settlements, Ministry of Public Works, Jl. Panyawungan, Cileunyi Wetan, Kab. Bandung 40939, Indonesia. 4 Indonesian Institute of Science, Jl. Gatot Subroto No.10 Jakarta 12190. Email: subyanto@cbn.net.id 5 Research Institute for Sustainable Humanosphere, Kyoto University, Gokasyo, Uji, Kyoto, 611-0011, Japan, Email: kkomatsu@rish.kyoto-u.ac.jp Figure 1. The floor plan of T.36 house. Utilization of engineered wood, Laminated Veneer Lumber (LVL) and glass fiber Concrete (GRC) that have not been popular in Indonesia needs studies of building materials that can be used with appropriate its function. The studies of shear wall carried out by completion the test in the laboratory; the connection interaction between Laminated Veneer Lumber (LVL) and Glass fiber Reinforced Concrete (GRC) fastened by steel nails tested and full scale structural testing of LVL member
connection in shear wall frame, with static monotonic compression and tensile force. The study was conducted with the analytical theory based on elastic analysis and analysis of test results. Table 1. Mechanical and Physical properties of LVL [2] Properties Value Unit Moisture content 10.7 (%) Density 540 (kg/m 3 ) Modulus of Elasticity parallel to the grain; 7511 (MPa) MOE Modulus of Rupture, parallel to the grain; 62.2 (MPa) MOR Modulus of Elasticity perpendicular to the 6174 (MPa) grain; MOE Modulus of Rupture, perpendicular to the 51.4 (MPa) grain; MOR Tension parallel to the grain Tension perpendicular to the grain Shear 2. EXPERIMENTAL STUDIES 40.8 (MPa) 1.8 (MPa) 5.4 (MPa) To be able to get home T.36 with material systems and structures that meet the requirements, conducted a series of tests, calculations and analysis to obtain the optimal design, both in structure and cost of construction. The standard house design for low-income people in Indonesia is an earthquake-resistant Type 36 [1], of which the floor plan is 6 x 6 m. It is constructed with LVL wall frame and sheathed by GRC, LVL roof frame with a corrugated metal roof tile at the middle to highest earthquake risk zone (zone 3-6) in Indonesia (Ministry of Public Works of Indonesia, 2002). Because most of the places in Indonesia are earthquake-prone, buildings must withstand earthquakes. In order to avoid excessive concentration of force on a structural component, shear walls are installed to provide a uniformly distributed stiffness, The laboratory testing to obtain the optimal structural design has been carried out; test of single steel nail of GRC sheathed and LVL shear wall frame member, and connection test between LVL frame members. 2.1 MATERIALS The shear wall element uses of two relatively new materials on building construction in Indonesia i.e. LVL and GRC. LVL is an engineered wood shown in Figure 2, made of Sengon wood (Paraserianthes Falcataria) and Rubber wood (Hevea Brasiliensis) taken from planted forest. Base material of LVL were the low quality wood but its fast growing tree, with technological treatment makes the LVL fulfill the requirement of structural component. The LVL cross-section that utilized as a shear wall frame member is 50 mm X 90 mm. Figure 2. The LVL engineered wood as a frame member of shear wall element. The GRC shown in Figure 3, made of concrete mortar of cement, sand, water, plasticiser (95%) with glass fibers (5%), Forton Polymer VF774 (5% of cement weight) produced with size of 2400 x 1200 x 9 mm. Cement-based building materials are gaining popularity for use, but the composite of this material with wood requires a study of the interaction between them. Mechanical properties of GRC showed in Table 2. Figure 3. GRC as sheathed of the shear wall elements. Table 2. Mechanical Properties of GRC Hand or Machine Premixed Properties Spray (MPa) (MPa) Dry Density 1.9-2.1 1.8-2.0 Ultimate Strength (MOR) 20-30 10-14 Elastic Modulus 10-20 10-20 Compression Strength 50-80 40-60 Technical Product of GRC & Construction PTE LTD. For fastener between frame member and sheathed materials use two kind of nails with specification is shown in Table 3.
Table 3. Nail specification [3]. Name Diameter Length Remarks (mm) (mm) N75 2.85 75 Between sheathing and frame N100 3.7 100 Between frame member The N-75 nail use as fastener for attached GRC to LVL and the N-100 nail for fastener between LVL frame members. The nails shown in Figure 4. Figure 6. Single nail test perpendicular to the grain of LVL material and GRC as a frame sheathed. Figure 4. Nails used as fastener of frame and sheathed [3]. 2.2 CONNECTION SPECIMEN To determine the behavior of the connection, two types of tests have been performed. The first is the behavior of the relationship between the LVL and the GRC, which is fastened with a steel nail with a diameter of 2.85 mm and length 75 mm, to do the test this monotonic single nail shear force parallel to the grain shown in Figure 5, and perpendicular to the grain shown in Figure 6, by using a Universal Testing Machines. The connection test was performed by the monotonic compression and tensile test was carried out to the LVL member joint. The joint between LVL member using 3.7 mm diameter and 100 mm length steel nails as fastener. The test is performed with the UTM. Figure 7. Middle connection test of LVL material as a frame member [3]. Figure 5. Single nail test parallel to the grain of LVL material and GRC as a frame sheathed. The UTM has integrated load cell and displacement measurement equipment and calculated automatically. To found the properties of the connections between LVL members, two types of connection tests have been performed. Full-scale test of middle joint, shown in Figure 7, and the full scale of end joint, shown in Figure 8 has done. Figure 8. End connection test of LVL material as a frame member [3].
The entire test was conducted on the Universal Testing Machine (UTM) with loading speed of 2 mm per minute for the tensile test and 0.5 mm per minute for the compression tests. These test data were used for numerical analysis to clarify the analytical calculations and structural test results. The GRC-LVL connection fastened by nails showed damage to the nails and LVL while the GRC has failure only in the nail hole, shown in Figure 10. The nail deformed extremely at the interface between GRC and LVL, and resulted in embedment in the LVL. At the end of the test sheet GRC pull out of LVL member. 3. EXPERIMENTAL RESULTS 3.1 SINGLE NAIL TEST ON GRC AND LVL The result of Non-Linear Calculation and test results of the GRC-LVL single nailed connection were shown on Figure 5 has done, with three specimens for parallel to the grain and three others for perpendicular to the grain. For this data, Non-Linear Calculation [4] result determined by a three-parameters equation shown in equation (1) was fitted up to maximum load for nonlinear calculation [3]. And beyond maximum load level, simple linear equation showed on equation (2), where, +) # "K s &-+ p = ( p u + K u! s)*1 " exp % s(.. (1) +, $ p u '/+ p = pmax - Ku2 (spmax -s).. (2) pu = 550 N, Ku = 10 N/mm, Ks = 1200 N/mm, Ku2 = 10 N/mm. The test results showed a rather scattered shown in Figure 9, but has a similar trend, this occurs because the attaching of GRC on LVL by nail as fastener by hand that is highly dependent on skill carpenter. The Curve was formed from equation (1) gives fairly good results, so it can be accepted as an equation to model the interaction between the LVL with GRC connection with steel nail fastener in between. Figure 10. The final condition of perpendicular single nail test 3.2 JOINT TEST RESULT The test of the connection between LVL members, fastened by nails showed that damage occurred at both the nail and LVL. In case of the parallel force to the nail, for tensile test on middle and end joint, the LVL member just loose from the connection, because the friction force only rely on the nail as fastener joint, condition after test shown in Figure 11. And for perpendicular test, the nail deformed in the perpendicular direction, while LVL embedment and nail holes became larger, so that finally the nails were pulled out. Figure 11. Middle-joint condition of LVL member after tensile test [3]. Figure 9. Connection test of LVL material and GRC as a frame sheathed.
Figure 12. Load (P)-Relative to displacement (S) and relationship of LVL middle-joint member fastened by nail [3]. In case of middle-joint the load (P) relative to the displacement (S) show that, for the LVL, the compression performance was dominant compared with tensile shown on Figure 12. Figure 14. Assemble of pre-fabricated house component in workshop. Interior panel of the shear wall using plywood with 6 mm thick, see Figure 14. While the outside using GRC panels with a thickness of 9 mm. Figure 15. The first wall panel element erection for half of T.36 house. Figure 13. Load (P)-Relative to displacement (S) and relationship of LVL end-joint member fastened by nail [3]. The house was constructed of half model of T.36, with floor plan 3000 X 6000 mm. Construction began by installing the foundation beam, followed by a stand the wall panels and finally, the installation of roof truss. Fasteners between panels were using steel bolts. The End-joint test result shows that, the load (P) to the displacement (S), the compression and the tensile performance was closely equal, shown on Figure 13. 3.3 MODEL HOUSE The results of analytical and experimental studies are used to build a model house with the pre-fabricated wall panels structure system and these pre-fabricated wall panels also serve as shear walls. These shear walls using materials and systems that have examined the connection performance. All elements of this house made in the workshop and then assembled at the construction site. All of structural and non-structural LVL engineered wood components. Opening the windows, doors and roof frame using 50 X 90 mm LVL wood, see Figure 13. Connections between components in the structural frame of the roof using a gusset plate made of plywood with a 9 mm thick. Figure 16. The half (3000 x 6000 mm) of T.36 prefabricated LVL-GRC model house.
4. DISCUSSION Analytical studies on the determination of the behaviour of LVL connection with GRC with nail as fastener by using equation (1) and (2) is quite close to the test results are somewhat spreading. Full-scale test results of LVL End-joint showed that the connection between member possess a good strength in tensile and compressive force. This behaviour is required when the structure strike by earthquake as a load cyclic horizontal loads. In other hand, Full-scale test results of LVL Middle-joint showed that the tensile test weaker than compressive force regime, it means that this joint have a good behaviour in compressive load only, when earthquake loading works on the structures. Guideline for the Structural Calculation of Two by Four Construction in Japan, Edited by Commitee of Guideline for the Structural Calculation of Two by Four Construction in Japan. Kogyou-Chousakai. The results of this test series gives good results and meet the design requirements, but there are a few things to be perfected. As with a foundation test results that have exceed the required capacity (RIHS, 2008). Some of LVL placement member configuration are changes on practical design, it has been different with the shear walls of the specimens that have been tested and replacement of sheath, these effort done because for decreasing of construction costs. 5. CONCLUSIONS Reliability study of the structure of pre-fabricated houses have been completed and gives a good results on the response due to the gravity load and lateral loads as a simulation of earthquake load required. Where the shear walls are the main structural elements that also serves as a partition wall. Reliability of connections between components LVL member with a nail fastener has a good response toward to design load. Further research is needed to find the optimal capacity of structural systems with the eligible reliability with low construction cost. ACKNOWLEDGEMENT We would like to express sincere thanks to the JSPS for financial support of research in Laboratory of Structural Function, RISH, Kyoto University, Japan and Laboratory of Structural and Construction, RIHS, Indonesia for all research activities. This research was supported in part by funds by Ministry of Public Works, Indonesia. REFERENCES [1] Ministry of Public Works of Indonesia (2002): Petunjuk Teknik Rumah Tahan Gempa. [2] A. Tjondro, M. Hadi, Mechanical properties and behavior of Falcataria-Rubber Wood LVL, Proceeding of 19th Australasian Conference On The Mechanics of Structures and Materials, Chrischurch, New Zealand 2006. [3] M. Hadi, S.Murakami, A. Kitamori., WS. Chang, K.Komatsu, Performance of Shear Wall Composed of LVL and Cement Fiber Board Sheathing, Journal of Asian Architecture and Building Engineering, 2010. [4] Japan 2x4 Construction Association (2007):