基于多性能指标的轻木-混凝土混合结构层间隔震

Inter-story Isolation of Light Wood-concrete Hybrid Structure Based on Multi-performance Indicators

鉴于上木下混结构在地震作用下具有明显的鞭梢效应,为了减轻震害并传承斗拱的构造特征,提出了一种新型木制隔震装置,将其应用于上木下混结构,形成层间隔震体系。通过该隔震装置的静载及拟静力试验,确定其性能参数及耗能能力;将木制隔震装置应用于上木下混结构进行层间隔震,并采用多质点动力模型进行地震响应分析,验证其隔震效果;基于上部结构相对侧移、底部结构加速度及底部剪重比3个性能指标,建立三质点模型,并进行参数优化设计,确定木制隔震层的关键参数区间。结果表明:该隔震装置具有足够的竖向承载力和耗能能力,应用于上木下混结构具有潜在的工程应用价值;该装置应用于木混结构中,在多遇地震作用下,减震效果不明显;在罕遇地震作用下,隔震支座产生了充分的滑移,并进入二次变形阶段,滞回曲线饱满,耗能充分;基于多性能指标的参数优化设计可有效控制上下部结构的地震反应,当隔震层最优频率比在0.2~0.4区间,最优阻尼比根据频率比的不同在0.15~0.4之间确定,可以达到良好的隔震效果。

The wood-concrete hybrid structure had obvious whiplash effect under earthquake.In order to reduce the seismic damage and inherit the configuration of ancient bracket,a new type of wooden isolation device was developed and installed between the upper wood and the lower concrete structure to form the inter-story isolation system.Through the static load and quasistatic test of the isolation device,the performance parameters and energy consumption capacity were determined.The wooden isolation device was applied to the wood-concrete hybrid structure of the upper wood and lower concrete for the layer separation,and the multi-lumped mass model was used for seismic response analysis to verify the isolation effect.Based on the three performance indicators of relative lateral displacement of superstructure,acceleration of substructure and shear weight ratio of substructure,the three-lumped mass model was established and the parameter optimization design was carried out to determine the key parameter range of the wooden isolation layer.The results show that the isolation device has sufficient vertical bearing capacity and energy dissipation capacity,and it has potential engineering application value when it is applied to the wood-conerete hybrid structures.When the device is applied to the wood-concrete hybrid structures under the action of frequent earthquakes,the damping effect is not obvious.Under the action of rare earthquakes,the isolation bearing produces sufficient sliding and enters the secondary deformation stage,with full hysteretic curve and the sufficient energy consumption.The parameter optimization design based on multi-performance indicators can effectively control the seismic response of the wood-concrete hybrid structure.When the optimal frequency ratio of the isolation layer is from 0.2 to 0.4,and the optimal damping ratio is determined according to the different frequency ratio from 0.15 to 0.4,good isolation effect can be achieved.