In the last two decades, high-rise timber buildings have been built using the glulam truss system, even with limited openings. Moment-resisting timber frames (MRTF) with semi-rigid beam-to-column connections can be an architecture-friendly way to provide a load-carrying system to vertical and horizontal loads for timber buildings. In these structures, connections of adequate ductility are crucial to ensure robustness and energy dissipation. This paper presents a review of the main types of timber beam–column moment connections with improved ductility and proposes to carry out a ductility assessment of these connections based on the most relevant ductility factors. Joints have a significant influence on the global performance of MRTF, and the application of ductile connections have improved the mechanical parameters of the timber frame. The reinforced bolted slotted-in steel plate and glued-in rods connections have similar mechanical performance, with high rotation capacity and good ultimate moment, but exhibited different failure modes under cyclic loading. The connections were classified within ductility classes. In general, the glued-in steel rods presented better results because of the high influence of steel profiles in the connection yielding. Despite the excellent mechanical behavior, the reinforced bolted slotted-in steel plate connections presented medium ductility values.

No abstract

No abstract

CLT panels have been investigated for reinforcement of existing masonry-infilled RC framed buildings through the increase of the overall lateral stiffness of the structure, thus reducing the story drift demand. The contribution of CLT panels depends on the connection to the RC frame elements. This paper evaluates the role of connectors by which CLT is attached to RC frames for capacity, ductility, and energy dissipation of the structure and its elements separately using different kinds of RC-CLT connections, and ultimately finds and compares the optimum number and arrangement of connectors. The results show that the geometry of connections plays a greater seismic role in RC frames than their mechanical properties. Regarding masonry infills, they allow a higher strength capacity but reduce the efficacy of CLT strengthening. However, strong connectors decrease the ability of infills in dissipation. Finally, in the optimum arrangement of connectors, they are distributed equally along the upper and lower beams at equal spacing, where CLT is added, starting in the middle of the beams and moving to the frame corners.

Cross-laminated timber (CLT) panels have been used as a renovation solution to be adopted in existing masonry-infilled RC buildings, especially those which were designed based on old seismic codes. The connections through which the panels are attached to the RC frames have shown to provide the most contribution to the seismic behaviour of buildings, highly depending on the type of connections used. In this study, to investigate the effect of design procedures of bilinear RC-CLT connections on the dissipated energy and peak displacement of the retrofitted building, their optimum number, location, and mechanical properties, including elastic/inelastic stiffness and yielding displacement, are aimed to be found using genetic a algorithm in a one-bay one-story RC frame. Two structures, (1) a masonry-infilled frame strengthened by CLT panel and (2) a CLT-infilled frame, are used to take the effect of masonry infill into account for two optimization purposes, maximum energy dissipation and minimum structural drift. Results show that under different predefined levels of structural performance, different optimum bilinear curves are achieved. In a parallel study, concerning connectors' arrangement, it was found that their horizontal distribution in beams, starting from the middle and moving to the corners, result in a much better response than a vertical distribution in columns.