In this paper, the relations between the load-deformation property of the CLT connections and the seismic performance of the 3 story CLT construction are analytically discussed. The static and the dynamic properties of the CLT connections led each from the static and the dynamic tests were obviously different, however the analytical results based on these properties were agree each with the results of the static and the dynamic tests proving the adequateness of estimated properties. The further study on the dynamic effects of CLT connections is necessary.
The connectors for the CLT shear wall with drift pin joint were suggested. The wall composed of five layers Japanese cedar CLT, steel connectors and drift pins (diameter d = 16mm). The horizontal shear performances of the walls were evaluated by static experiment and 2D frame analysis. The experimental parameter was number and position of drift pins. Characteristic failure was shear failure on the border of the laminae. There were good agreement on initial stiffness, yield load and second stiffness between experiment and calculation.
Journal of Structural and Construction Engineering: Transactions of AIJ
Summary
In this paper, the new type of seismic retrofit method using CLT panels as shear walls is proposed. In this method, setting small CLT panels in RC frame and bonding each panel and panel to RC frame with epoxy resin, panels compose shear walls. The advantages of this technique are: There are less dust, noise, and vibration during construction; Light weight panels enable easy construction and short construction period; Light weight panels also cause small seismic force.
In this research, cyclic loading tests for 5 types of reinforced specimens and 2 types of plain RC frames as control were conducted.
The stress analysis showed that the bond strength between CLT and RC and shear modulus of CLT in these specimens match the result of element tests. So the specimen strength could be divided into the RC frame strength and the CLT strength until the initial deformation. As the bond strength between CLT and RC was smaller than the shear strength of CLT, the specimens can be stronger by increasing the adhesive area.
The purpose of this study is to develop a high strength leg joint for shear wall made of small size cross laminated timber panel in a simple system. The joint of CLT in which steel plate was inserted in the central slit and fixed by high strength bolt at inside of short steel pipes was proposed. In order to grasp the failure mode and strength of CLT member, material tests on embedment and shear were carried out using small CLT blocks. The test results indicated that there is few reinforce effect by cross bonding of each lamina. It was concluded that the precise estimation of the strength of CLT member is important in order to develop the joint proposed in this paper.
The Japanese domestic forests have never been maintained enough, and it was a great fear that the multiple functions of the forest such as watershed conservation, the land conservation, and so on has been declined. The construction employing the cross laminates timber (CLT) panels was offered as a method of large scale building in domestic and foreign countries. However, the seismic design method of CLT panel construction has never completed. So, in order to consider the seismic design method, the shaking table tests and static lateral load tests were conducted to the modelized CLT panel construction.
A reduction coefficient is applied in usual design of multiple dowels type connections. The numbers of stiffeners in row is one of important factor to decide this coefficient. CLT drift pinned joint showed small orthotropy against in plane tensile load. Tensile tests of multiple drift pins joints were performed to evaluate the effect of array. Numbers of drift pins n in each specimen were same (n=12), but the arrangements were different (2 x 6, 3 x 4, 4 x 3, 6 x 2). Also the grain directions were parameters (0, 90 degrees). The reduction of initial stiffness and proportional limit load showed good agreement between theoretical prediction and experimental results.
Various kind of in-plane bending tests of cross laminated timber (CLT) with different shapes have been previously carried out. The results indicate that the bending strength of CLT loaded in plane reduces as the number of layer increases. To evaluate this lamination effect on in-plane bending strength of CLT, a computational model based on Monte Carlo method was developed. The estimated bending strength showed the same tendency.
The national research project to investigate proper structural design method for CLT (Cross Laminated Timber) buildings has been advanced by the subsidy of the Ministry of Land, Infrastructure, Transport and Tourism of Japan since 2011. This paper provides the outline of shake table tests executed as a part of the project in February 2015. Two specimens, one (Specimen A) is five story and another (Specimen B) is three story, were tested. As the result, for both specimens damage was rather slight by the strong input wave according to the Building Standard Law of Japan. Finally, Specimen A survived three dimensional input wave of 100% of JMA Kobe (strong ground motion recorded during Kobe Earthquake in 1995), and Specimen B survived 140% of JMA Kobe.
In this paper, the results of lateral loading tests on two types of CLT shear wall systems with an opening are summarized, one is the shear wall system with assembling narrow size CLT panels and another is that using one large size panel with an opening. 8 types, 13 specimens in all were tested. Load-displacement curves were obtained and characteristic values of shear performance were derived. As a result, the assembly system revealed higher ductility because of the ductility of connections between panels, while the rapture of large panel system was brittle though the shear capacity was higher than the assembly system.
The national research project to investigate proper structural design method for CLT(Cross Laminated Timber) buildings has been advanced by the subside of the Ministry of Land, Infrastructure, Transport and Tourism of Japan since 2011. This paper provides the outline, research item and main result stream of the project. Full-scaled building tests and element tests for evaluating seismic performance are described in this paper mainly. Numerical studies have been also conducting as well.
