摘要
考虑剪切变形和剪切滑移的影响,提出了一种适用于分析连续钢-混组合梁(steel-concrete composite continuous beams, SCCCBs)动力特性的理论模型。把连续钢-混组合梁的n-1个中间支撑代替为未知反力Ri(i=n-1),从而连续组合梁的动力学问题退化为承受未知荷载的简支组合梁动力学问题。通过Laplace变换和逆变换,得到包含未知反力的振型函数。代入梁端和中间支撑边界条件,即可获得关于n-1个未知反力的线性方程组,由其系数矩阵行列式不为0即可求得自振频率。模型中把混凝土子梁和钢梁分别按照独立的Timoshenko梁单元考虑,相比于子梁同剪切转角假设模型和不考虑剪切变形的模型,具有更高的计算精度。最后,分析了剪切变形、边中跨比和跨高比等因素对连续钢-混组合梁自振特性的影响。结果表明:该理论计算结果具有更高的计算精度;当L/(nh)>10时,可忽略剪切变形对连续钢-混组合梁自振频率的影响。
Considering the effect of shear deformation and shear slip,an analytical model for analyzing the dynamic characteristics of steel-concrete composite continuous beams(SCCCBs)was proposed.Firstly,the n-1 intermediate supports of the SCCCB were replaced by the unknown reaction R_(i)(i=n-1),so the dynamic problem of the SCCCB was reduced to that of a simply supported composite beam bearing unknown loads.Then,the vibration mode function of the SCCCB bearing unknown reactions was obtained by the Laplace transform and inverse Laplace transform.Finally,the linear equations for n-1 unknown reactions were established by substituting the boundary conditions at beam ends and the middle supports.The eigenfrequencies of the SCCCB were calculated by making use of the non-zero determinant of the coefficient matrix of the linear equations.In the model,the concrete sub-beam and steel beam were considered as independent Timoshenko beam elements respectively.This supposition can get higher calculation accuracy than the assumption that both sub-beams have the same shear angle and that the shear deformation is not considered.The effects of shear deformation,the ratio of side to main span,and span to depth ratio on the natural vibration characteristics of the SCCCB were analyzed.The results show that the proposed method has higher calculation accuracy.The influence of shear deformation on the natural frequency of the SCCCB can be ignored,when L/(nh)>10.
作者
孙琪凯
张楠
刘潇
SUN Qikai;ZHANG Nan;LIU Xiao(School of Civil Engineering,Beijing Jiaolong University,Beijing 100044,China)
出处
《振动与冲击》
EI
CSCD
北大核心
2023年第2期258-266,共9页
Journal of Vibration and Shock
基金
国家自然科学基金(52178101)
中央高校基本科研业务费专项资金(2020YJS121)。
关键词
连续钢-混组合梁(SCCCB)
剪切变形
自振特性
边中跨比
跨高比
steel-concrete composite continuous beam(SCCCB)
shear deformation
natural vibration characteristics
ratio of side to main span
span-to-depth ratio
作者简介
第一作者:孙琪凯,男,博士生,1992年生;通信作者:张楠,男,博士,教授,1971年生。
