Enhancement of mechanical characteristics and novel damage assessment for timber post and beam structures with K-braces

Abstract

Glued-laminated Timber Post and Beam Structural System (GTPBSS) gains widely application in timber engineering because of direct force transmission and simple construction. The present work investigates the influence of introducing K-bracing on the lateral performance of the GTPBSS. To this end, four full-scale GTPBSS specimens with and without braces under horizontal loading conditions were carried out. The obtained test results highlight that the GTPBSS without braces exhibited large deformation. The failure modes predominantly centered on the occurrence of wood cracking at both the column-base joint and beam-column joint. In contrast, the GTPBSS specimens equipped with K-bracing elements exhibited failure modes marked by the instability of the brace components. The inclusion of brace system within the GTPBSS structures yielded positive results, effectively reducing lateral deformations while concurrently augmenting both the elastic stiffness and the later maximum load-carrying capacity. However, it is essential to exercise caution with regard to potential out-of-plane instability. A dual-parameter damage assessment model was developed to evaluate structural damage, incorporating factors related to energy dissipation and deformation. The evaluation results derived from this model were consistent with the test results, affirming the rationality and validity of the proposed approach. This model is expected to provide a scientific foundation for formulating strategies for repair and maintenance.