混合设计的高性能钢梁抗弯性能试验

采用两点加载的方式, 对3片混合设计的高性能HPS 485W工字钢梁进行抗弯性能试验, 分析了截面几何参数对试验梁抗弯承载力、弹塑性变形和破坏形态的影响。结合跨中单点加载的试验结果, 对比分析了不同加载方式对试验梁抗弯承载力的影响, 建立了能够准确模拟试验梁抗弯过程的有限元模型, 在非厚实截面范围内对混合设计的高性能钢模型梁进行了关键参数的数值分析。分析结果表明: 对两点加载的试验梁, 抗弯破坏形态为纯弯段区出现受压翼缘与受压区腹板的局部屈曲; 随着翼缘宽厚比的降低, 钢梁的塑性转动能力明显提高; 随着腹板高厚比的增加, 钢梁的抗弯强度和延性均会降低; 对相同几何尺寸的模型梁, 加载方式改变时, 钢梁的抗弯过程相似, 但控制钢梁失效的破坏形态不同; 对混合设计的钢梁, 建议腹板与翼缘材料强度等级差不大于2个强度等级。

Bending behavior test of hybrid high performance steel beam

Bending behavior tests were conducted for 3 hybrid high performance HPS 485 W I-shape steel beams with the method of two-point loading.The influences of cross profile geometric parameters on bending capacity, elastic and plastic deformations, and failure mode of test beam were analyzed.Considering the test results under midspan one-point loading, the influences of different loading methods on bending capacity of test beam were analyzed.Finite element models were established to accurately simulate bending procedures of test beams.Parameter analysis was conducted for hybrid high performance steel beams under the condition of non-compact cross profile.Analysis result shows that the failure modes of two-point loading test beams are local bucklings at both compressive flange and compressive web in pure bending field.The plastic rotation capacity of steel beam increases obviously with the decrease of flange width to thickness ratio.The bending capacity and ductility decrease with the increase of web height to thickness ratio.For beams with same dimension, the bending procedures are similar when adopting different loading methods, but the buckling modes marking the failure of beam are different.It is suggested for hybrid steel beam that the steel grade of web should be not beyond two grades lower than the strength grade of flange.