论文部分内容阅读
提出了2种新型双管翼缘钢-混凝土组合梁截面形式:钢梁上翼缘为圆形钢管混凝土、下翼缘为矩形钢管混凝土(DFCG-1)与钢梁上、下翼缘均为矩形钢管混凝土(DFCG-2)的管翼缘组合梁。为研究此2种双管翼缘组合梁的抗弯性能,对1根DFCG-1和1根DFCG-2进行了跨中双点对称加载试验,分析了试验梁的变形、应变变化规律。依据试验梁弹性、弹塑性状态下的实测受力性能,采用简化弹塑性理论及结合应力-应变协调的弹塑性理论推导了双管翼缘组合梁屈服弯矩、极限抗弯承载力的简化计算公式。研究结果表明:试验梁破坏时表现出明显的塑性弯曲破坏特征,其破坏过程可分为弹性、弹塑性与破坏3个阶段;加载过程中,试验梁未出现平面内与平面外整体失稳,且未发生局部弹性失稳破坏;梁端钢管与内填混凝土间无相对滑移,管翼缘与混凝土翼板间最大滑移小于1.3mm,钢混组合截面各部分协同工作性能较好;DFCG-1,DFCG-2的位移延性系数分别为3.68,4.53,体现出较好的延性性能;DFCG-1,DFCG-2在抗弯刚度、承载力、破坏形态等力学性能上总体表现基本一致,但当翼板混凝土因压溃而退出工作后,DFCG-1更低的腹板高度使其较DFCG-2具有更好的腹板屈曲稳定性;所提公式计算结果与试验值吻合较好,可用于双管翼缘组合梁抗弯承载性能计算分析。
Two new types of double-flange steel-concrete composite beams are proposed. The cross-section forms of the steel-concrete composite beams are that the upper flange of the steel beam is a circular CFST, the lower flange is a rectangular steel tube concrete (DFCG-1) and the upper and lower flanges of the steel beam are rectangular steel tubes Pipe flange composite beam for concrete (DFCG-2). In order to study the flexural behavior of the two kinds of double-flanged composite beams, two DFCG-1s and two DFCG-2s were loaded in a mid-span two-point symmetric manner. The deformation and strain of the test beams were analyzed. Based on the measured mechanical properties under the elastic and elasto-plastic conditions of the test beam, the simplified calculation of the yield moment and the ultimate flexural capacity of the double-tube flange composite beam is derived by using the simplified elasto-plastic theory and the elasto-plastic theory based on the stress-strain coordination formula. The results show that the test beam exhibits obvious plastic bending failure when it is damaged, and the failure process can be divided into three stages: elasticity, elasto-plasticity and failure. During the loading process, the test beam does not appear in-plane and out- And there was no local elastic instability failure. There was no relative slip between the steel tube and the filled concrete at the beam end, and the maximum slip between the flange and the concrete vane was less than 1.3mm. The workability of each part of the steel-concrete composite section was better. DFCG 1 and DFCG-2 respectively, the displacement ductility coefficients are 3.68 and 4.53, respectively, showing good ductility. The overall performances of DFCG-1 and DFCG-2 are basically the same on the mechanical properties such as flexural rigidity, However, the lower web height of DFCG-1 has better web buckling stability than that of DFCG-2 when the concrete slab exits due to crushing. The calculated results agree well with the experimental values, Calculation and Analysis of Bending Bearing Behaviors of Composite Beams with Dual Tubes and Flanges.