Analysis of influencing factors on the seismic performance of RC beam-column exterior joints based on orthogonal experimental design

Abstract

Due to the frequent earthquakes in recent years, the importance of studying the seismic performance and optimizing the influencing factors of beam-column exterior joints has become increasingly significant. This paper designed nine RC (reinforced concrete) beam-column exterior joints, taking into account concrete strength, the anchorage style of steel bars, and reinforcement ratio as influencing factors. Quasi-static loading tests were conducted on these nine RC beam-column exterior joints utilizing an orthogonal experimental design (OED) of three factors and three levels (L₉(3³)). The failure mode, hysteretic performance, skeleton curves, ductility, cumulative energy dissipation, and ultimate bearing capacity of the joints were assessed. Additionally, the impact of variations in these factors on seismic performance was investigated. Variance analysis and range analysis were conducted on the test results to determine the primary and secondary order of factors influencing the seismic performance, thereby identifying the optimal levels of these factors. The results indicated that all three factors significantly affect on the ductility, cumulative energy dissipation, and ultimate bearing capacity. The primary and secondary orders as well as the optimal levels of the three factors, are as follows: (1) for ductility, the primary and secondary orders are: reinforcement ratio > concrete strength > anchorage style, with the optimal level being: C70 + two-sided welding +1.63%; (2) for cumulative energy dissipation, the primary and secondary orders are: concrete strength > reinforcement ratio > anchorage ratio, with the optimal level being: C70 + two-sided welding +2.08%; (3) for ultimate bearing capacity, the primary and secondary orders are: reinforcement ratio > concrete strength > anchorage style, with the optimal level being: C70 + 90-degree hooks +2.58%. From the above discussion, this paper provides a theoretical reference for optimizing the design of factors that impact the seismic performance of RC beam-column exterior joints.