Seismic behaviour of fibre-reinforced-polymer- and steel-strengthened timber connections

Abstract

In the event of a seismic attack, the structural integrity of moment-resisting timber frames in the joint region may become compromised and hence the joint may not be able to transfer bending moment around the frame. Often, replacement of a damaged joint is not an option and hence efficient but effective strengthening and repair schemes for such joints are necessary. This article reports the results of 15 tests on 10 metal dowel-type moment-resisting timber connections subjected to monotonic or cyclic loading. Joints are either strengthened or repaired with epoxy, fibre-reinforced polymer composites or steel plates. The ability of the test joints to resist the imposed cyclic loading is presented in the context of hysteresis responses. Recommendations for strengthening and repair interventions are made based on strength, stiffness, ductility, energy dissipation and damping characteristics of the test joints.

Moment Resistance Performance of Larch Laminated Timber Beam-Column Joints Reinforced With CFRP

“…According to Gehloff et al (2010) and Yang et al (2019), splitting failure occurred in the columnbeam joint of the unreinforced moment of resistance specimen in the cyclic tests, which was also observed in the control specimen in this study.…”

“…The Type-B3 specimen may have exhibited sufficient ductility because the CFRP reinforced at the joint suppressed the brittle failure of the member (Fig 7e). Thus, the CFRP suppressed the splitting failure by improving the joint capacity of the column-beam joint, showing a similar trend to the studies by Xiong et al (2017) and Yang et al (2019). Furthermore, as the reinforcement ratio of the CFRP increased, the joint capacity and ductility were improved, and the failure was suppressed in the end distance direction.…”

“…As a result of the experiment, the reinforcement of CFRP around the joint showed a tendency to increase the maximum strength capacity of the joint and suppress the brittle fracture. Yang et al (2019) confirmed the superior performance of CFRP by conducting cyclic tests on joints with multiple reinforcement methods for preventing the loss of joint capacity due to structural damage during earthquakes. However, Xiong et al (2017) showed disadvantages of the reinforcement method, that wrapping CFRP lowered the yield moment and ductility ratio and had poor aesthetics.…”

“…However, Xiong et al (2017) showed disadvantages of the reinforcement method, that wrapping CFRP lowered the yield moment and ductility ratio and had poor aesthetics. In the experiment of Yang et al (2019), the yield strength increased, but the ductility ratio decreased in some specimens. To check the effect of CFRP insertion reinforcement on the performance of wood joints, Lee (2021) conducted the bearing strength test on larch square timber inserted and reinforced with different CFRP reinforcement ratios.…”

“…They determined that the maximum moment and yield moment were improved by 75% and 22%, respectively, compared with that of the nonreinforced joint. Compared with the reinforcement method of Yang et al (2019) and Xiong et al (2017), the insertion reinforcement effect was slightly improved. In this study, the Type-A and Type-B specimens reinforced with CFRP exhibited superior strength and stiffness than the control specimen.…”