钢木混合结构在不同性能水准下的层间位移角限值

Inter-story Drift Limits under Different Performance Levels for Timber-steel Hybrid Structures

钢木混合结构是一种主要由钢框架、内填轻型木剪力墙和钢木混合楼盖组成的新型结构体系。抗震设计中,层间位移角是衡量结构和非结构破坏程度的重要指标。为获得钢木混合结构在不同性能水准下的层间位移角限值、定义钢木混合抗侧力体系的屈服点,在有限元软件OpenSees中对120个不同参数的钢木混合抗侧力体系进行推覆模拟,得到具有95%保证率的屈服位移角为0.48%;为定义钢木混合结构倒塌极限状态性能点,选取10条不同地震记录,在有限元软件OpenSees中对考虑不同木剪力墙和钢框架抗侧刚度比的三层和六层钢木混合结构进行增量动力分析,得到具有95%保证率的倒塌极限状态层间位移角为2.43%。基于分析结果和已有试验现象,建议钢木混合结构立即居住和防止倒塌性能水准层间位移角限值分别取0.5%和2.5%。

Timber-steel hybrid structures consist of steel moment-resisting frames,infill wood shear walls and timber-steel hybrid diaphragms.Inter-story drift is adopted as an important indicator of structural or non-structural damage in seismic design.In order to obtain inter-story drift limitations under different performance levels for timber-steel hybrid structures,120 timber-steel hybrid lateral load resisting systems with different configurations were numerically subjected to monotonic loading protocol in the Open System for Earthquake Engineering Simulation(OpenSees)framework.The yield drift considering95% reliability was obtained as 0.48%.Then,the drift for collapse prevention limit state of timber-steel hybrid structures was defined.Ten seismic records were selected and the incremental dynamic analysis(IDA)was performed on 3-story and 6-story hybrid structures considering three different lateral stiffness ratios.The drift for collapse prevention limit state considering95% reliability was obtained as 2.43%.Based on the numerical results and previous test results,0.5% and 2.5% were recommended as the inter-story drift limits under the immediate occupancy(10)and the collapse prevention(CP)performance levels for the timber-steel hybrid structures,respectively.