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提出了新型波形钢腹板-双管弦杆-混凝土板组合梁,混凝土顶板与双钢管混凝土下弦杆由波形钢腹板连接。为了分析新型组合梁在正、负弯矩作用下的受弯性能,进行了组合连续梁的受弯试验,研究了试验梁的破坏模式、变形特性、应变特性与混凝土顶板裂缝发展规律。根据试验结果,提出了新型组合梁的变形和承载力计算方法,并验证了方法的有效性。试验结果表明:在正、负弯矩区段,组合截面波形钢腹板各测点纵向应变很小,跨中和支点处纵向应变峰值仅为下弦杆的3.7%和5.1%,可忽略不计;混凝土顶板和钢管混凝土下弦杆纵向应变沿截面高度方向基本呈线性变化,满足平截面假定,在外荷载作用下共同受力;当组合试验梁达到开裂荷载140kN时,主梁跨中挠度理论计算值为5.8mm,试验值为5.5mm,误差约为5%,当组合试验梁跨中截面达到极限抗弯承载力时,荷载理论计算值为399kN,试验值为415kN,试验值略高于理论计算值,但两者误差很小,约为4%,说明该组合梁的挠度和抗弯承载力理论计算方法简单、可靠。
A new type of corrugated steel web-double-pipe chord-concrete composite beam is proposed. The concrete roof and the double concrete-filled steel chords are connected by corrugated steel webs. In order to analyze the flexural behavior of the new composite beam under positive and negative bending moment, the bending behavior of the composite continuous beam was studied. The failure modes, deformation characteristics, strain characteristics and crack propagation of the concrete beam were studied. According to the test results, the calculation method of the deformation and bearing capacity of the new composite beam is proposed, and the effectiveness of the method is verified. The test results show that the longitudinal strain at each measuring point of the steel plate with the combined cross-section corrugations is very small at the positive and negative bending moments, and the longitudinal strain peaks at the mid-span and fulcrum are only 3.7% and 5.1% of the lower chord. The longitudinal strain of the concrete roof and the concrete filled steel tubular chord changes linearly along the height of the section and meets the assumption of flat section under the action of external load. When the combined test beam reaches the cracking load of 140 kN, the calculated theoretical deflection of the midspan of the main beam is 5.8mm, the test value is 5.5mm, the error is about 5%. When the cross-section of the composite test beam reaches the ultimate flexural capacity, the calculated value of the load is 399kN, the test value is 415kN, the test value is slightly higher than the theoretical value , But the error between the two is small, about 4%, indicating that the theoretical calculation method of deflection and flexural capacity of the composite beam is simple and reliable.