钢砼组合结构PBH剪力键的疲劳性能

为了研究钢箱-砼组合结构中PBH剪力键在反复荷载作用下的疲劳性能，设计制作了PBH剪力键试验模型，进行了24万次疲劳推出试验。在疲劳破坏形态和试验滑移及应变数据分析的基础上，利用数值工具开展肋板开孔孔径、穿入钢筋直径、混凝土强度3个参数的PBH剪力键疲劳寿命影响因素分析。研究表明：PBH剪力键的疲劳破坏形态与静载破坏相似，表观表现为混凝土面多处斜向劈裂裂缝、内部榫孔混凝土压碎、穿入钢筋局部屈服；疲劳破坏演化过程分为疲劳损伤开始、发展、破坏3个阶段，其中疲劳发展阶段占整个疲劳阶段的91.7%，结构刚度在疲劳损伤开始和发展阶段退化较慢，在疲劳破坏阶段退化较快；肋板开孔孔径、穿入钢筋直径、混凝土强度3个参数对PBH剪力键疲劳寿命影响均有明显影响，其中穿入钢筋直径对疲劳寿命的影响尤为突出。

Fatigue performance analysis of steel concrete composite structure PBH shear connectors

PBH test model is designed and 240000 times fatigue tests were conducted to investigate the steel box-concrete composite structure of PBH shear connector under repeated load fatigue performance. The fatigue failure pattern and test data are analysed. Take advantage of the finite element software to analysis the floor opening aperture, wear into the steel bar diameter, concrete strength influence of the PBH fatigue. Results showed that the PBH''s fatigue failure pattern is similar to static, which is concrete surface appear oblique splitting cracks, concrete tenor crushed, through the steel yield. Fatigue damage can be divided into beginning and development and damage three stages, the development stage accounted for 91.7% of the whole fatigue stage, structural stiffness in the beginning and development stages degradation slower, fast during the damage stage. Three parameters are of great influence on the fatigue life of PBH, among them through the bar diameter''s influence particularly prominent.