Research On Mechanical Properties Of Steel-concrete Honeycomb Composite Beam Under Negative Bending

Because of the continuous opening of the web,the honeycomb structure will weaken the web to a certain extent.Under the combined action of negative bending moment and shear force,the steel-concrete honeycomb composite beam will appear more complex force state and failure mode.In this paper,the mechanical behavior of steel-concrete honeycomb composite beam under the combined action of negative bending moment and shear force is studied by means of experimental method.Based on the experimental data,the influence of web height-thickness ratio,flange width-thickness ratio and concrete slab reinforcement ratio on its mechanical properties is analyzed.The static loading test of two steel-concrete honeycomb composite beams and one pure steel honeycomb beam under concentrated load was carried out to observe the failure form.The results show that the bending failure of steel-concrete honeycomb composite beam under the joint action of bending shear occurs when concrete is pulled.By comparing with pure steel honeycomb beam,it is found that 100 mm thick concrete floor slab can increase the ultimate load of honeycomb composite beam by 7% under the combined action of negative bending moment and shear force.When transverse stiffeners are arranged on the pier slab of steel-concrete honeycomb composite beams,the yield load of the specimens does not change significantly compared with that of the honeycomb composite beams without stiffeners,but the stiffeners can the ultimate load of the honeycomb composite beam when the concrete is pulled is effectively improved.at the same time,due to the limitation of the transverse stiffening rib on the out-of-plane displacement of the pier slab,the failure mode changes from the buckling failure of the beam to the tearing failure of the cross-mesh angle.By means of finite element simulation software ABAQUS and according to the test data,a fine finite element model is established.By changing the corresponding parameters,the ratio of web height to thickness,flange to width and reinforcement ratio in concrete slab are studied.For concrete tension,the influence law of yield load and ultimate load of steel-concrete honeycomb composite beam under the joint action of bending shear is studied,and the corresponding conclusions are drawn.The results show that the ratio of web height to thickness has a certain influence on the yield load and ultimate load of honeycomb composite beam,and the decrease trend of ultimate load of steel-concrete honeycomb composite beam with stiffening rib is slightly larger than that without stiffening rib.of steel-concrete honeycomb composite beams.With the increase of flange width ratio,the yield load and ultimate load decrease more obviously.The decreasing trend of ultimate load of steel-concrete honeycomb composite beam with stiffening rib is slightly smaller than that of steel-concrete honeycomb composite beam without stiffening rib.It is found that the ratio of web height to thickness is more significant than the ratio of width to width of flange when the concrete is pulled.At the same time increasing the reinforcement ratio in concrete slab can obviously increase the cracking load of concrete slab under tensile condition.