高强度工字钢梁腹板抗剪性能试验

发布时间：2018-08-05 18:51

【摘要】：为了充分利用高强钢的高强度特性,设计了4片采用Q420qD高强度腹板的焊接工字钢梁,并采用跨中单点加载的形式进行抗剪性能试验研究。分析了腹板高厚比、翼缘约束效应、剪跨比等关键参数对高强度工字钢梁抗剪性能的影响规律,研究了高强度Q420qD腹板的抗剪极限承载能力及剪切破坏机理,并验证建议理论模型的正确性与腹板抗剪承载力计算公式对高强度钢梁的适用性。研究结果表明:试验梁在腹板弹性剪切屈曲后均形成了拉力带,充分发挥了屈曲后强度,最终形成框架机构;基于试验结果确定了高强度工字钢梁腹板的拉力带分布形式与破坏框架模型,其可作为高强度工字钢梁腹板的剪切失效理论模型;采用较大的翼缘相对腹板刚度,可提供更强的剪切抗力,理论计算时应计入翼缘对腹板的约束效应,试验与理论计算的对比分析结果验证了高强度工字钢梁翼缘对腹板约束系数的合理取值应为1.25,理论模型与计算公式适用性强;随着剪跨比的增大,试验梁的腹板屈曲后强度均充分发展,但试验梁在弹性屈曲后的腹板面外变形明显减小,仅在临近剪切极限强度时腹板面外变形呈不收敛增长,因此高强度腹板设计时应兼顾腹板面外屈曲变形的控制与腹板屈曲后强度的有限利用,保证高强钢桥使用阶段的安全可靠。
[Abstract]:In order to make full use of the high strength characteristics of high strength steel, four welded I-beam beams with Q420qD high strength web plate were designed, and the shear properties of four I-beam beams were studied by single point loading in the middle span. The influence of the key parameters of web height to thickness ratio, flange restraint effect and shear span ratio on the shear resistance of high strength I-beam is analyzed. The ultimate shear bearing capacity and shear failure mechanism of high strength Q420qD web plate are studied. The correctness of the proposed theoretical model and the applicability of the web shear bearing capacity formula to high strength steel beams are verified. The results show that the tensile band is formed after the elastic shear buckling of the web plate, and the post-buckling strength is brought into full play, and finally the frame mechanism is formed. Based on the test results, the tensile band distribution form and failure frame model of high strength I-beam web plate are determined, which can be used as the shear failure theory model of high strength I-beam web plate, and the relative web stiffness of flange is adopted. Can provide stronger shear resistance, and the theoretical calculation should take into account the restraint effect of the flange on the web, The results of comparison and analysis between the test and the theoretical calculation show that the reasonable value of constraint coefficient of high strength I-beam flange to web should be 1.25, the applicability of theoretical model and calculation formula is strong, and with the increase of shear span ratio, The post-buckling strength of the web of the test beam is fully developed, but the out-of-web deformation of the test beam decreases obviously after elastic buckling, and only when the ultimate shear strength is near, the out-of-plane deformation of the web does not converge. In order to ensure the safety and reliability of high-strength steel bridges, the control of out-of-plane buckling deformation and the limited use of post-buckling strength should be taken into account in the design of high-strength web.
【作者单位】：长安大学公路大型结构安全教育部工程研究中心;中交第一公路勘察设计研究院有限公司;
【基金】：国家重点基础研究发展计划(“九七三”计划)项目(2015CB057706) 国家自然科学基金项目(51378070,51408056) 交通运输部应用基础研究项目(2014319812080) 中央高校基本科研业务费专项资金项目(310821153501,310821151015)
【分类号】：U446

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