In-plane Behavior Of Composite Frame Slab Considering The Out-of-Plane Composite Effect

The floor slab is one of the most complex structural components in a frame structure.The flexible in-plane diaphragm effect and the coupling of in-plane and out-of-plane effects of the floor slab has been a great difficulty in refined structural simulations.Therefore,the complex structural behavior of the composite floor slab and its refined simulations is becoming the key scientific problems in the promotion of steel-concrete composite structure to complex structural systems.Aiming at this problem,this dissertation conducted experimental study and numerial modeling on the in-plane behavior of composite floor slab considering the out-of-plane composite effect.The main works and conclusions are as follows:(1)Experimental study on the in-plane behavior of a composite floor slab considering the out-of-plane loading.In the study,an experimental program to realize the coupling in-plane and out-of-plane loading was designed.A series of experiments on three large-scale composite floor slab substructure was conducted,including a pure in-plane loading test and two negative-moment-coupled in-plane loading test after a cyclic out-of-plane loading test.Analyses of the experimental results are focused on the in-plane behavior of composite floor slab(crackling development,f ailure mode,and load-displacement response)and the influence of out-of-plane loading on the in-plane stiffness and strength behavior.(2)High-efficiency numerial modeling of the in-plane behavior of composite floor slab considering the out-of-plane composite effect: model reviews and developments.In the reviews,the selection of computational models for the in-plane and out-of-plane effects of the floor slab based on their loading pattern is investigated.The classical fiber model and multi-layer shell model for modeling the composite frame and floor slab systems are discussed.The drawbacks of the current computational models for the floor slab are reviewed,which shows the direction on developing better high-efficiency floor slab models.In the model developments,a simplified floor slab model neglecting the flexible in-plane diaphragm effect is integrated,and a new high-efficiency floor slab model considering the flexible in-plane diaphragm effect is developed.Based on the multiple-vertical-line-element-model(MVLEM),the high-efficiency model recommends a calibrated in-plane shear macro constitutive model,and proposes the influence of out-of-plane effect on the in-plane shear macro constitutive relationship.(3)Validation and application of the high-efficiency in-plane computational model of composite floor slab considering the out-of-plane composite effect: experimental simulation and structural system analysis.In the experimental simulation,refined beam-shell combining model is used for simulating the out-of-plane loading test,and the developed high-efficiency computational model is used for simulating the in-plane and out-of-plane loading tests.Comparisions with the experimental results validated the developed high-efficiency floor slab model in simulating the failure mode,computing the total deformation and the flexural/shear deformation component,and considering the influence of the out-of-plane composite effect on the in-plane behavior.In the structural system analysis,the two integrated and developed models are used,including the application of the simplified slab model in simulating a regular structural system with negligible flexible in-plane diaphragm effect and the new high-efficiency model in simulating an irregular structural system with large-aspect-ratio floor slab and end shear-walls.