۱- Introduction

۲- Prior research on CLT shear walls

۳- Classification of structural system

۴- Target structure

۵- Experimental program

۶- Discussion

۷- Conclusions

References

Abstract

A national research project to investigate proper structural design methods for cross-laminated timber (CLT) buildings has been initiated by a subsidiary of the Ministry of Land, Infrastructure, Transport and Tourism of Japan since 2011. In the final stage of the project, shaking table tests were conducted for CLT buildings designed according to a proposed structural design procedure which confirmed damage limit state, safety limit state, allowable stress, and ductile factors, etc. This paper presents results of shaking table testing for full-scaled CLT building and a design procedure. The three different systems examined are buildings composed of narrow panels, wide panels with an edge tensile connection, and wide panels with an edge tensile connection for each no-window shear part. The focus of this paper is the building of narrow panels. This building system is suitable for midrise CLT building with high ductility produced through rocking. The structure was shown to behave well during severe strong motion as specified in the Japanese building standard law and to have survived the 1995 Kobe earthquake despite the occurrence of a compressive rupture in shear walls which are support elements against the vertical load. Story shear capacity calculated from a numerical model and element tests (such as connections) were safely evaluated; but to evaluate the capacity correctly, further research is required in the element and system levels. Though a variety of undetermined issues and challenges remains, the Building Standard Law and Notification for three different CLT construction systems was enforced in April 2016 to ensure the construction of safe CLT buildings.

Introduction

Though Japanese domestic forests planted after 1945 have grown enough to be used as building components or elements of composite material, they have never been sufficiently used and maintained to plant a subsequent generation. So, it is a major concern that multiple functions of the forest, such as watershed and land conservation, have declined. To address this situation, “The Act for Promotion of Use of Wood in Public Buildings” was established and enacted in October 2010. Meanwhile, construction employing cross-laminated timber (CLT) panels was offered as a method for large scale and mid-rise building in domestic and foreign markets. According to Japanese building standards law, special permission using time history analysis is normally required to build a construction composed of new structural materials and members, such as CLT was not adequately covered. The use of time history analysis is widespread in Japan, but it is difficult to employ for mid-rise or low-rise residential buildings, mainly due to the structural design cost and length of design time. To save costs and avoid delays, a definition of the standard strength of materials and members and the development of a structural design procedure are required. In addition, typical structural details are required. The capacity spectrum method for seismic design, which is known as the “limit strength calculation method” in Japan is applicable for structural design. The structural specification of building method can be eliminated in this method, but a definition of standard strength and procedure for calculation, such as a damping factor, is required. A national project of research and development on CLT construction for solving the above problems was started in 2011.