均布荷载作用下简支组合梁受力机理分析

为了揭示组合梁在均布荷载作用下的受力机理，考虑弯曲和滑移耦合变形，建立组合梁滑移受力机理模型.首先，以单跨简支组合梁为研究对象，探讨组合梁变形与滑移规律、横截面内力分布及结合部传力机理；然后，分析截面尺度、界面刚度与荷载加载面对组合梁受力机理的影响.结果表明：混凝土板抗剪和抗弯作用在房建组合梁中较明显，在桥梁组合梁中可忽略；随着界面刚度比的增加，简支组合梁的曲率、转角、挠度和滑移均减小；混凝土板和钢梁轴力同步增大，混凝土板剪力增大而钢梁剪力减小，混凝土板、钢梁弯矩减小而轴力力偶增大；结合部界面切向力增大而界面法向力基本不变；相较于按自质量分配荷载，均布荷载由混凝土板承担时界面压力增大，由钢梁承担时则界面受拉，应注意验算界面抗拉拔性能.

Stress Mechanism Analysis of Simply Supported Composite Beam Under Uniform Load

In order to reveal the stress mechanism of composite beam under uniform loads, the slip and bearing mechanism model of composite beam was established considering the coupled deformation of bending and slip. Taking the single-span simply supported composite beam as the research object, the deformation and slip of composite beam, the internal force distribution in cross section and the force transfer mechanism at the joint were discussed. The influence of section scale, interface stiffness and loading surface on the stress mechanism of composite beam was analyzed. The results show that the shear resistance and bending resistance of concrete slab are obvious in composite beam of building engineering, but could be ignored in the composite beam of bridges. With the increase of interface stiffness ratio, the curvature, rotation angle, deflection and slip of simply supported composite beam decrease; the axial force of concrete slab and steel increase synchronously, the shear force of concrete slab increases while that of steel beam decreases, and the bending moment of concrete slab and steel beam decreases while the axial force couples increase; the interface tangential force of the joint increases while the interface normal force is basically unchanged. Comparing with the load distributed according to its own weight, the interface pressure increases when the uniform load is undertaked by the concrete slab, and the interface is in tension when the uniform load is undertaked by the steel beam,so the pullout resistance of the interface should be checked.