Prediction of Nonlinear Cyclic Behaviors of Shear Wall Composed of Acacia mangium Framing and Fiber Cement Board Sheathing

The alternative types of composite structure made of wood and cement based building materials needs to meet with the high demand for earthquake-resistant houses in Indonesia. In order to understand the mechanism of earthquake resisting performance of shear wall, it is necessary to investigate not only elastic behavior of shear walls but also non-linear one. In this study, series of full-scale experiments on timber frame shear walls composed of Akasia wood (Acacia mangium) sheathed by Fiber Cement Board (FCB) were carried out. For predicting skeleton curve, a series of theoretical equations was derived, which cannot only solve arbitrary nail pattern shear wall but also nonlinear behavior after yielding. Further, for describing hysteresis loops of shear walls, so-called Normalized Cyclic Loop (NCL) model was adopted. By combining two theoretical approaches, weintended to predict whole cyclic shear wall behaviors tested. Good agreements were obtained from comparison between experiment and prediction. The information obtain by this study will be useful for practical engineers or structural designers to design the high performance earthquake resisting timber houses.

Evaluation of Screw Reinforcement on Bearing Performance of Wood Depending on Screw Position

In this study, the reinforcement of wood by screws for partial compression perpendicular to the grain was studied. For the estimation of stiffness and strength, the reinforcement effect of screws depending on their position under the loading plate was evaluated by taking into account the internal displacement distribution of the wood. The finite element analysis (FEA) was used to investigate the internal displacement distribution of the wood. Then an approximate function that can be applied to various internal displacement distributions under loading plate was proposed. From the shear resistance mechanism between the screw and wood by taking their relative displacement distribution into consideration, the equations to estimate the initial stiffness and yield strength of the bearing performance of the wood reinforced by screws were derived. Then partial compression test was carried out for wood reinforced by screws with setting screw thread at various positions. The values obtained by the equations corresponded with the tendency of the experimental results. It was found that the screw reinforcement is more effective when its thread is positioned as much as distant from the contact surface.

Prediction of Reinforcement Effect by Screw on Triangular Embedment Perpendicular to the Grain with Variation of Screw Locations

In this study, the reinforcement by screws for the wood perpendicular to the grain subjected to a rotational moment has been studied. For the estimation of rotational stiffness and yield moment, the reinforcement effect by the screws which varies depending on their position under the bearing plate was evaluated by taking the internal displacement distribution of the wood into account. The Finite Element Analysis (FEA) was used to investigate the internal displacement distribution of the wood. Then an appropriate function was found out to meet well with various internal displacement distributions under the bearing plate. The equations, which can estimate rotational stiffness and yield moment of the bearing performance of the wood reinforced by screws, were derived from the shear resistance mechanism between the screw and wood by considering their relative displacement distribution. Then rotational tests were carried out with the wood reinforced by the screws, setting screw thread at the various positions. Agreements between prediction and experimental results were very well. It was found that the screw reinforcement was effective, provided screw length should be longer for the wood height.

Dynamic and Static Behaviors of Shear Wall with Openings Composed of LVL and Fiber Cement Board Sheathing

The shear wall with and without openings that served as a structural element or/and partition wall was utilized in a low-cost housing for the low-income people in Indonesia. The houses,however,should be withstoodfrom earthquake inertial force, so there must be no casualties when disaster struck. The alternative types of composite structure made of wood and cement based building materials needed to meet with the high demand for earthquake-resistant houses in Indonesia. In order to understand the mechanism of earthquake resisting performance of shear wall, we needs to investigate behavior of shear wallsnot only for cyclic static but alsofor dynamic loading. In this study, theseries of full-scale experiment on timber frame shear walls with and without openings,compose of Laminated Veneer Lumber (LVL) engineered wood (Paraserianthes Falcatariaand Hevea Brasiliensis) and sheathed by Fiber Cement Board (FCB), was carried out.By analyzing testing result using theoretical approaches, we intended to predict static initial stiffness and yielding strength as well as basic dynamic properties shear walls. For static behavior, good agreements were obtain from comparison between experiment and theoretical prediction based on mechanical model. While, for dynamic behavior, agreement was not sufficient due tothe effect of bending and rocking of actual test specimens. The information obtain by this study will be useful for practical engineers or structural designers to design the high performance earthquake resisting timber houses with a low construction cost.