装配式槽钢-混凝土组合梁受弯性能研究

Flexural behavior of prefabricated steel channel-concrete composite beams

为研究采用螺栓连接的装配式槽钢-混凝土组合梁(PSCCB)的受弯性能,制作了7个不同宽跨比、梁高和剪切连接间距的PSCCB试件,对其进行四点弯曲测试。基于ABAQUS软件建立PSCCB有限元模型,通过试验结果验证模型的可靠性,并分析螺栓间距、螺栓预紧力、抗剪连接件间距、剪跨比、宽跨比、槽钢强度和混凝土强度对PSCCB受弯性能的影响。试验结果表明:高强度螺栓能确保PSCCB具有较高的整体性和良好的强度和延性;随着宽跨比增大,PSCCB抗弯承载力和延性分别提高8%~19%和11%~21%;穿孔钢板剪力连接件在槽钢和混凝土板之间提供高效的组合作用,部分抗剪连接与完全抗剪连接PSCCB的延性、强度、刚度差异少于10%;与梁高320 mm的PSCCB相比,梁高400 mm的PSCCB的抗弯承载力提高96%,但延性降低10%。分析结果说明:有限元分析结果与试验结果较吻合,所建立的模型能准确反映PSCCB的受弯性能;随着螺栓间距和预紧力的增大,PSCCB受弯承载力和初始刚度基本保持不变;适当增加抗剪连接程度和宽跨比能有效提升PSCCB的受弯承载力和初始刚度;增加槽钢强度能显著提高PSCCB的受弯承载力,而混凝土强度变化对其受弯承载力影响较小。根据试验和有限元参数分析,提出PSCCB受弯性能设计方法,受弯承载力和跨中挠度计算值与试验及有限元分析结果吻合良好,可为PSCCB的工程设计提供参考。

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.