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Vertical static loading tests were carried out on two kinds of continuous span concrete composite slabs with beam and slab connected by studs and open-hole folding plate connectors. Combined with the test results, on the basis of the analysis of load–deflection curves and load-reinforcement strain curves, the finite element software ABAQUS was used for the numerical study of the continuous span concrete composite slabs. The plate thickness, concrete strength, thickness of the shear key and slab span has carried on the finite element analysis. The results show that the strength of the concrete and the thickness of the shear bond have little effect on the flexural performance of the continuous span concrete composite slab, but the shear bond can strengthen the connection between the slab and the steel beam and reduce the sliding and lifting of the composite slab on the steel beam. The slab thickness and slab span have a great influence on the flexural performance of continuous span concrete composite slabs. The peak load of the specimen increases with the increase of slab thickness and decreases with the increase of slab span. This study will provide a theoretical basis for future design and engineering application of composite slabs.

The welded joint of steel structure is prone to occur fatigue fracture under dynamic loads. In this paper, an experimental study on the fatigue performance of base material, butt weld, and cross fillet weld of high-strength steels were investigated. The S-N curve was fitted, and the corresponding fatigue life was predicted. Results corroborate that the base material of high-strength steel possess high fatigue resistance. AISC360 and EC3 standard design curves are applicable for the evaluation of the butt weld fatigue performance of Q460D and possess adequate safety margin, but only suitable for low-fatigue life estimation of Q690D butt weld. With respect to cross fillet weld, AISC360 design curve not only is suitable for the fatigue life analysis of Q460D and Q690D but also has enough safety margins, while EC3 and BS7608 codes possess relatively low fatigue limit. In addition, a quantitative analysis on fatigue fracture was conducted on the basis of fatigue damage theory, and the fatigue crack propagation law was disclosed on the basis of fracture morphology. The crack propagation law before instant fracture is consistent with damage development, and the fatigue striation width increases gradually with damage development. The fast crack propagation stage accounts for a small proportion in the fatigue life, thereby indicating that this stage is insufficiently developed.

Steel plate shear wall (SPSW) systems have dual characteristics, the frame and infill wall action. The connection flexibility of frame joint not only changes the force and moment distribution, but also increases the lateral displacement and weakens the overall stability in SPSW structure. This paper presents the influence of hinged, rigid and semi-rigid connection joints on the behavior of SPSW structures. The bearing capacity, energy dissipation mechanism, failure mode, stress and deformation development process of the semi-rigid composite frame with steel plate shear walls under different stiffener forms were studied using experimental tests and finite element analysis. It was observed that with stiffeners the specimen yield load increased about 20% on the elastic stage, the ultimate bearing capacity of the diagonal stiffener was about 5% larger than the cross stiffener on the plastic stage, but the overall failure modes were basically the same. Additionally, the quantitative indications of the effect of joint stiffness on load carrying capacity were presented.