基于能量法的GFRP管与混凝土板组合梁轴向力计算

GFRP管与混凝土组合梁能够共同工作是通过剪力连接件来实现,而工程中应用的连接件一般为柔性件.连接件在传递GFRP管与混凝土界面上的水平剪力时,会产生变形,从而在GFRP管与混凝土板的界面上引起滑移,这种滑移会导致GFRP管、混凝土翼缘板、连接件的受力性能发生变化.针对这一问题,基于最小势能原理并结合组合梁实际受力特征,建立了考虑组合梁界面相对滑移影响的轴向力微分方程,给出对称集中荷载下组合截面中GFRP管和混凝土板的轴向力理论计算公式.计算结果表明,组合梁的轴向力随着连接刚度的增大和外荷载增加而增大,随着GFRP管壁厚度增加而减小.组合梁跨中截面轴向力最大,从跨中到梁端按非线性逐渐减小,梁端部轴向力近似为零.

Calculation of Axial Force Acting on GFRP-Concrete Composite Beam via Energy Method

The GFRP-concrete composite beam, i.e. combining the GFRP tube with concrete slab, is available to work by means of the shear connectors as flexible connectors. However, the connectors will be deformed when transferring interfacial shear force, thus causing the slip between GFRP tube and concrete slab. The interfacial slip will result in the stress redistribution between GFRP tube, concrete flange plate and shear connectors. Based on the principle of minimum potential energy and according to the structural and load bearing characteristics and variational principle, some differential equations of axial force are derived taking account of the effect of interfacial slip, as well as the theoretical formulae of the axial force acting on both the concrete slab and GFRP tube in the composite beam under symmetrically concentrated load. The calculated results showed that the axial force acting on the composite beam increases with the increasing connector stiffness and external load and decreases with the increasing wall thickness of GFRP tube. And the maximum axial force is found at the midspan, then it decreases gradually from midspan to beam end where it is approximately zero.