基于板式GFRP剪力连接件的预制混凝土三明治板的组合度研究

Study on composite action of precast concrete sandwich panels with plate-type GFRP shear connectors

通过基于板式GFRP剪力连接件的预制混凝土三明治板试件的静力受弯试验,进行了刚度及承载力组合度的计算,并基于通用有限元软件ANSYS建立试件的三维有限元力学模型,对其受力全过程进行了数值模拟。在验证了有限元分析模型准确性的基础上,对预制混凝土三明治板在不同板式GFRP连接件布置方式、材料性能、几何尺寸的整体刚度进行了分析,并将之与完全组合板刚度的理论值进行了对比(两者比值定义为刚度组合度)。分析结果表明:随剪跨段板式GFRP剪力连接件的抗剪刚度的提高,预制混凝土三明治板的刚度组合度呈非线性增长趋势,但其增长幅度逐渐变缓;随着保温层厚度的增加,刚度组合度有较大幅度的降低,但随着剪力连接件厚度的增加,刚度组合度对保温层厚度的敏感性下降。有限元分析结果亦表明:板式GFRP连接件对三明治板承载力组合度的影响没有对刚度组合度的影响显著;按照现有的板式GFRP剪力连接件设计方法很难达到完全组合的效果,在设计中应充分考虑对刚度的折减。

Based on existing static tests of concrete sandwich panels with plate-type glass fibre-reinforced polymer( GFRP) shear connectors,two different percentages of composite action were firstly analyzed using the member stiffness and the member strength as the indices,respectively. Three-dimensional finite element( FE) analyses were then conducted based on the commercial software package ANSYS to reproduce the full-range load-deflection behavior of the composite panel specimens. Based on the validated FE model,parametric studies were further conducted to investigate the effects of the GFRP shear connectors' layout,their material property and their geometrical dimension on the stiffness of the sandwich panel. The obtained stiffnesses were then compared with the theoretical values of fully composite sandwich panels,where the ratio of the two was defined as the percentage of composite action of stiffness( PCAS). The FE results indicate that: the PCAS of sandwich panels increases with the global shear stiffness provided by the GFRP shear connectors in the shear span while the increasing rate reduces gradually; with the increase of the insulation thickness,the PCAS decreases with the increase of the plate thickness of the GFRP shear connectors while the decreasing rate reduces; and the parameters of the GFRP shear connectors influence more significantly the PCAS than the percentage of composite action of strength of the sandwich panel. Since it is hard to use the plate-type GFRP shear connectors to realize a full composite action of the sandwich panel,stiffness reduction should be carefully considered during a practical design.