Hybrid multistory buildings are every day more common in the construction industry. However, there is little understanding of the performance of the hybrid connections. In this research, the static and dynamic response of cross-laminated timber (CLT) composites combined with reinforced concrete (RC), hollow steel profiles and laminated strand lumber (LSL) has been investigated. In addition, the effects of posttensioning stresses as well as distinct types of connectors such as nails, self-tapping screws and self-tapping dowels has been accounted for. After experimental work, numerical modelling for simulating the static and dynamic behavior for these hybrid connections was also investigated. Results indicate that such massive timber composite connections behave reasonably similar to conventional timber connections, except in that inelastic deformations may increase up to 200%. In addition, it has been found that existing hysteretic models like the modified Stewart hysteretic model (MSTEW) fit for modelling purposes except that very asymmetric hysteretic behavior can be found for timber-concrete hybrid connections.

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This investigation covers the lateral performance of a new concept of hybrid timber shear wall, and includes individual connection testing, full-scale shear wall testing and numerical modeling. The main objective of this study is to develop enhanced timber structural solutions that facilitates the design and construction of mid-rise timber buildings in areas with high seismic demand. The new shear wall concept involves structural configurations similar to those found in conventional light-framed timber shear wall, but using glulam members as framing elements, connected to OSB sheathing panels using conventional nails. More specifically, the OSB sheathing is embedded within grooved glulam members in order to enhance the lateral capacity and stiffness of the wall. Connections and full-scale monotonic and cyclic shear wall testing were performed, and the results indicated that it is possible to obtain a high performing timber shear wall with the proposed concept. In particular, the obtained values are promising with strength and stiffness levels that are 3 times that of a conventional CLT shear wall. Furthermore, the proposed prototype comprises 0,89 m3 of wood volume, which represents less than one-fourth of the amount of wood in a CLT shear wall of equivalent lateral capacity. In addition, the ductility obtained for the proposed concept can be classified as high ductility class (HDC) according to the Eurocode 8. It is expected that the ductility may be further improved by limiting potential brittle failure observed in of one of the framing members at high displacement levels. Finally, it was found that available modelling tools with hysteretic models, such as the MSTEW, is capable of predicting the lateral strength and stiffness of the proposed concept, since modeling errors below 10% were obtained.

This paper examines the seismic behavior of CLT-steel hybrid walls at six- and ten-story heights to increase seismic force resistance compared to a conventional wooden wall. The ultra-strong shear walls proposed in this paper are called Framing Panel Shear Walls (FPSW), which are based on a robust articulated steel frame braced with CLT board panels and steel tendons. Timber structures are well-known for their ecological benefits, as well as their excellent seismic performance, mainly due to high strength-to-weight ratio compared to steel and concrete ones, flexibility, and redundancy. However, in order to meet the requirements regarding the maximum inter-story drifts prescribed in seismic design codes, a challenging engineering problem emerges, because sufficiently resistant, rigid and ductile connections and lateral assemblies are not available for timber to meet both the technical and economical restrictions. Therefore, it is a necessity to develop strong and cost-effective timber-based lateral systems, in order to become a real alternative to mid- and high-rises, especially in seismic countries. In this investigation, the dynamic response of cross-laminated timber (CLT) combined with hollow steel profiles has been investigated in shear wall configuration. After experimental work, an investigation was also carried out into numerical modelling for simulating the cyclic behavior of a hybrid FPSW wall and the spectral modal analysis of a six- and a ten-story buildings with FPSW. A FPSW shear wall can double the capacity and stiffness.