Flexural behavior of prefabricated steel channel-concrete composite beams

To study the flexural behavior of prefabricated steel channel-concrete composite beams (PSCCBs) with bolted connections, seven PSCCB specimens, with varying width-to-span ratios, beam depths and shear connector spacing, were fabricated and subjected to four-point bending tests. A finite element model (FEM) of PSCCBs was established using ABAQUS. The reliability was verified through experimental results. The effects of bolt spacing, bolt preload, shear connector spacing, shear-to-span ratio, width-to-span ratio, channel strength, and concrete strength on the flexural behavior of PSCCBs were analyzed. The test results demonstrated that high-strength bolts guaranteed that the composite beam exhibited excellent structural integrity, strength and ductility. As the width-to-span ratio increased, the flexural capacity and ductility of PSCCBs increased by 8%～19% and 11%～21%, respectively. The use of perforated steel plate shear connectors enabled efficient composite actions between channels and concrete slabs, and the discrepancy in ductility, strength, and stiffness between PSCCBs with partial and full shear connections was less than 10%. In comparison, beams with a depth of 400 mm showed a 96% higher flexural capacity but 10% lower ductility than those with a depth of 320 mm. The conclusions are drawn as follows. The FEM results are in good agreement with the experimental results, proving the model ’ s capability to accurately evaluate the PSCCBs ’ flexural behavior. As the bolt spacing and preload increase, the flexural capacity and initial stiffness of PSCCBs remained basically unchange. Increasing the degree of shear connection and width-to-span ratio can effectively enhance the flexural capacity and initial stiffness of PSCCBs. Although increasing the channel strength can significantly improve the PSCCBs ’ flexural capacity, changes in concrete strength exert a more minor impact on their flexural capacity. Based on the insights from the experimental investigation and FEM-based parametric analysis, a design method for the flexural behavior of PSCCBs is developed. The calculated values of flexural capacity and mid-span deflection can align well with the experimental and FEM results, which can provide a reference for the engineering design of PSCCBs. © 2024, Central South University Press. All rights reserved.