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为了研究高强度工字钢梁的抗弯性能和延性,基于混合设计的理念,采用中国产高强度、高性能钢HPS485W(名义屈服强度为485 MPa)和传统钢种Q345,设计并加工了3片简支工字钢梁,在跨中加载对试验梁进行抗弯试验。试验后分析试验梁的应力变化、变形特征、破坏形态及承载能力。分析结果表明:在有效的侧向约束下,高强度钢梁最终破坏时跨中均形成塑性铰,试验梁的最终破坏形态均为跨中附近受压翼缘和受压区腹板的局部屈曲;对于混合设计的高强度钢梁,翼缘和腹板材料有合理的强度匹配范围,当采用强度较高的HPS485W翼缘时,建议腹板钢材强度的选取不低于Q345;翼缘的尺寸效应是影响试验梁抗弯承载力和延性的重要因素,随着翼缘宽厚比的增大,在试验梁屈服后的非弹性阶段,受压翼缘局部屈曲出现的较早,且受压翼缘的局部屈曲程度更显著,降低了钢梁非弹性阶段的变形能力。
In order to study the flexural strength and ductility of high strength I-beam, based on the concept of hybrid design, the Chinese-made high strength and high performance steel HPS485W (nominal yield strength 485 MPa) and the traditional steel Q345 were designed and processed 3 Simple supported I-beam, loaded in the span of the test beam for bending test. After the test analysis of the test beam stress changes, deformation characteristics, damage morphology and bearing capacity. The analysis results show that under the effective lateral restraint, the plastic hinge is formed in the mid-span of the high-strength steel beam and the ultimate failure state of the beam is the local buckling of the compression flange and compression zone web near the mid-span ; For mixed-design high-strength steel beams, the flange and web materials have a reasonable strength matching range. When adopting the HPS485W flange with higher strength, it is recommended that the strength of the web steel be selected not less than Q345; the size of the flange The effect is an important factor that affects the flexural capacity and ductility of the test beam. As the ratio of flange width to thickness increases, in the non-elastic stage after yielding of the test beam, the local buckling of the compression flange occurs earlier and the compression of the flange The local buckling degree is more significant, reducing the deformation capacity of the beam in the inelastic stage.