集簇式栓钉抗剪承载力折减系数计算方法

为给装配式钢-混组合结构梁桥集簇式栓钉抗剪连接件的设计提供参考,深入研究了集簇式栓钉抗剪连接件的受力特性。采用ABAQUS有限元软件建立推出试验有限元模型,对群钉效应及其主要影响因素进行了有限元参数化分析,并给出综合考虑混凝土强度、栓钉排数、栓钉纵向间距影响的集簇式栓钉连接件抗剪承载力折减系数计算公式。结果表明:受到群钉效应的影响,集簇式栓钉连接件的单钉平均抗剪承载力有较大程度的折减并且钉群受力呈现明显的不均匀性; 随着混凝土强度的提高,φ22×200栓钉连接件抗剪承载力、抗剪刚度逐渐增大; 当栓钉排数从3排增加至7排时,群钉的单钉平均抗剪承载力以及栓钉抗剪承载力折减系数逐渐降低,同时钉群受力的不均匀程度大幅提升; 当栓钉纵向间距由4d(d为栓钉直径)增加至8d时,群钉的单钉平均抗剪承载力以及栓钉抗剪承载力折减系数呈现增大趋势; 提出的集簇式栓钉连接件抗剪承载力折减系数计算公式计算值与有限元值吻合良好,可以为装配式钢-混组合结构梁桥集簇式栓钉抗剪连接件的设计提供理论依据。     

Behaviour of embedded steel plate in composite coupling beams

Plate-reinforced composite (PRC) coupling beam is fabricated by embedding a vertical steel plate into a conventional-reinforced concrete coupling beam to enhance its strength and ductility. Shear studs are welded on the steel plate surfaces to allow for proper load transfer between the concrete and steel plate. The present study focuses on the evaluation of internal load distributions and load sharing on the embedded steel plate as well as at the shear studs in composite coupling beams using the nonlinear finite element package ATENA. The proposed two-dimensional finite element model is able to simulate the overall load-deflection behaviour and internal load distributions of coupling beams subjected to bending and shear forces. The reliability of the model is demonstrated by comparisons with the available experimental results. This is followed by an extensive and carefully planned parametric study using the calibrated finite element model. Numerical results on the effects of steel plate geometry, span-depth ratio of beams and steel reinforcement ratios at beam spans and in wall regions are presented and discussed in this paper. The finite element model provides a better understanding of the behaviour of shear studs as well as plate anchorage in the wall regions and embedded beam region. Based on the numerical results, equations for quantifying the shear stud forces are established and a set of non-dimensional design charts for determining the internal forces of the embedded steel plates is constructed. Both of them are useful for engineers to design PRC coupling beams.