Analysis Of Longitudinal Cracking Of Steel-concrete Composite Beams

Steel-concrete composite beam through the shear connector connect the steel beam withthe flange plate thus the beam can work together and deformation harmoniously. Longitudinalcrack occurred if the concrete flange plate of Steel-concrete composite beam affected shearforce of shear connector and the crack may lead to the destruction of the beam.In this paper, longitudinal crack of the flange plate of Steel-concrete composite beamwas analyzed and researched detailedly. First, a theoretic analysis is made to the problem oflongitudinal crack, introduce the calculation model of longitudinal shear of Steel-concretecomposite beam and computational methods of the concrete flange plate longitudinal shearcapacity. Afterwards, the paper analyzes two factors of most that affect the longitudinal crackof the concrete flange plate. Lastly, nonlinear finite element analysis method is used toimitate longitudinal crack of Steel-concrete composite beam.Conclusions are demonstrated and elicited as follows:1.Cracks appear near the external forces first, with the load increases, they extend to theboth ends and midspan of the beam, so the transverse reinforcement near the external forcesshould be more intensive appropriately.2.The size of the ratio of reinforcement influence the failure modes and ultimate bearingcapacity of the composite beams. Transverse reinforcement play an important role in controlthe development of longitudinal crack. The size of the ratio of transverse reinforcementshoulu be maintaining between0.5%and0.6%, thus the regulation about the the smallestratio of transverse reinforcement in the current regulation is relatively conservative. Thelayout of reinforcement should be in different layers in order to control crack developmentbetter.3.Transverse spacing distance between the studs could be enlarged properly to reducethe peak value of crosswise tension stress and alleviate the crack. In on longitudinal, theconcentrated force which studs act on the concrete flange plate will be superimposing if thelayout of studs is excessively intensive, and that the concrete flange plate will be crack easily.Decrease longitudinal space between studs in the shear span and increase it properly in purebending segments in practice.