部分包覆钢-混凝土组合梁在负弯矩作用下的刚度分析  

Stiffness Analysis for Partially Encased Steel-Concrete Composite Beams Subjected to Hogging Bending Moment

作　　者：龚树红 陈刚[2] 顾明明[1] 胡夏闽[1] Shuhong Gong;Gang Chen;Mingming Gu;Xiamin Hu(College of Civil Engineering,Nanjing Tech University,Nanjing 211816,China;The Third Construction Co.,Ltd.,of China Construction Eighth Engineering Division,Nanjing 210046,China)

机构地区：[1]南京工业大学土木工程学院,南京211816 [2]中建八局第三建设有限公司,南京210046

出　　处：《钢结构（中英文）》2023年第6期51-60,共10页Steel Construction（Chinese & English）

基　　金：江苏省建设系统科技项目(2022ZD10)。

摘　　要：随着理论研究和工程应用的不断发展,人们发现与普通钢-混凝土组合梁相比,部分包覆钢-混凝土组合梁(PEC梁)不仅具有良好的抗火性能,其承载力、刚度和抗屈曲能力均有大幅度提高。为研究PEC梁在负弯矩作用下的受力性能和刚度计算方法,对3根不同力比的PEC梁和1根钢-混凝土组合梁进行静力弯曲试验,并探讨了部分包覆组合梁在负弯矩作用下其钢梁腹部钢筋混凝土对截面刚度的影响。试验结果表明:在负弯矩作用下,PEC梁的受弯承载力与刚度相较钢-混凝土组合梁分别提高40%和25%,极限承载力随力比的增大而增大;PEC梁的翼板混凝土裂缝宽度要明显小于普通组合梁,PEC梁的翼板混凝土和腹部混凝土的裂缝宽度随着其配置的纵向钢筋截面面积的增大而减小;负弯矩作用下混凝土受拉开裂导致组合梁截面刚度逐渐减小,腹部混凝土随着裂缝的延伸其作用逐渐减弱,但是腹部混凝土受到钢梁制约其裂缝并未贯通,因此对PEC梁的刚度仍有贡献;当荷载趋近极限承载力时,荷载-挠度曲线逐渐趋于平缓,表明PEC梁具有良好的延性;组合梁早期均满足平截面假定,后期随着荷载增大,混凝土板与钢梁间的相对滑移逐渐增加,导致连接界面处混凝土应变与钢梁应变差逐渐增大。在试验研究的基础上,考虑钢梁腹部混凝土及钢梁与混凝土板连接界面相对滑移对组合梁刚度的影响,提出了适合PEC梁在负弯矩作用下的截面刚度计算公式,试验结果验证了所提计算方法的准确性。As theoretical research and engineering applications continue to advance,partially encased steel-concrete composite beams(PEC beams)have been shown to exhibit not only superior fire resistance but also significantly enhanced load-bearing capacity,stiffness,and resistance to buckling when compared to traditional steel-concrete composite beams.In order to study the mechanical performance and stiffness calculation methods of PEC beams subjected to hogging bending moment,static bending tests on three PEC beams with different force ratios and one steel-concrete composite beam were conducted.In addition,the effect of reinforced concrete between the flanges of steel beam on the bending stiffness under negative bending moment was also analyzed.The experimental results suggest that the flexural capacity and stiffness of PEC beams subjected to hogging bending moment compared with steel-concrete composite beam are increased by 40%and 25%,respectively.The ultimate bearing capacity of PEC beams increases with the increase of the force ratio.The width of cracks observed in the flange concrete of PEC beams is significantly smaller than that of normal composite beam.Furthermore,it has been observed that the crack width in both the flange concrete and web concrete of PEC beams decreases as the cross-sectional area of the longitudinal reinforcement increases.When subjected to negative bending moments,the section stiffness of the composite beams experiences a reduction due to the occurrence of tensile cracking within the concrete.As these cracks continue to propagate,the contribution of the web concrete to the overall stiffness of the beam gradually diminishes.Nevertheless,given that the web concrete is confined by the steel beam and that cracks have not fully penetrated it,concrete between the flanges remains capable of contributing to the stiffness of PEC beams.When the load approached its maximum capacity,the load-deflection curves gradually flatten which indicates favorable ductility characteristics of PEC beams.During the init

关 键 词：部分包覆钢-混凝土组合梁(PEC梁) 截面刚度 负弯矩作用 静力弯曲试验 滑移效应 

分 类 号：TU398.9[建筑科学—结构工程]