预应力腹板开洞钢-木组合梁抗弯性能研究

Research on Flexural Performance of Steel-Wood Composite Beams with Prestressed Web Holes

【目的】为了研究体外预应力腹板开洞钢-木组合梁在四点弯曲静载作用下的变形和受力性能。【方法】通过有限元软件ABAQUS建立三维实体模型,研究预应力钢绞线布置形式和洞口形状等参数对组合梁刚度、变形和承载能力的影响规律和程度。【结果】结果表明:设置预应力钢绞线可以显著提高组合梁的刚度和承载力,使折线型的初始刚度和屈服承载力分别增强41%和25%,直线型效果次之;未设置预应力的组合梁跨中洞口处容易发生应力集中和较大变形;洞口形状影响洞口区域应力重分布情况,长方形洞口底部两侧容易出现塑性铰,正方形洞口这种现象得到部分改善,圆形洞口底端钝角容易发生应力集中和变形。【结论】选择合适的预应力钢绞线布置形式和洞口形状可以显著提高腹板开洞对钢-木组合梁刚度和承载力,减少变形程度。

[Purposes]This paper aims to study the deformation and mechanical properties of external pre-stressed steel-wood composite beams with web holes under four-point bending static load.[Methods]Three-dimensional solid model was established by finite element ABAQUS to study the influence of pre-stressed steel strand layout and hole shape on the stiffness,deformation and bearing capacity of compos-ite beams.[Findings]The results show that the stiffness and bearing capacity of the composite beam can be significantly improved by setting prestressed steel strand,and the initial stiffness and yield bearing ca-pacity of the curved beam can be increased by 41%and 25%respectively,followed by the effect of the straight beam.Stress concentration and large deformation are easy to occur at the opening in the span of composite beams without prestressing.The shape of the hole can redistribute the stress in the area of the hole,the plastic hinge is easy to appear on both sides of the bottom of the rectangular hole,the phenom-enon of the square hole is partially improved,and the obtuse angle at the bottom of the round hole is easy to occur stress concentration and deformation.[Conclusions]Selecting the proper layout of the pre-stressed steel strand and the shape of the opening area can significantly improve the stiffness and bearing capacity of the steel-wood composite beam with web holes and reduce the degree of deformation.