摘要
钢-混凝土连续组合梁在负弯矩区的侧向失稳是一种畸变屈曲,国内还没有合适的设计计算方法。假设上部混凝土楼板在畸变屈曲过程中不变形,并假设下翼缘侧向失稳时工字钢腹板和翼缘之间只存在侧向移动相互约束,不存在相互的转动约束,用能量方法求出了纯弯梁弹性畸变屈曲临界应力。对大量截面用ANSYS有限元分析结果与近似计算公式的比较,表明公式有很好的精度。对于畸变屈曲半波数为1的情况,引入波长修正系数,结果与ANSYS结果比较也符合良好,能够满足实际工程的需要。对于其他支座形式,也进行了相应的有限元分析,通过修正的增大系数来考虑其有利影响。对变弯矩的情况,在理论分析和有限元模拟的基础上,提出了偏于安全的等效弯矩系数公式。
At present there is no simple way to check the distortional buckling of I-sectional beams in the negative moment region of a continuous composite beam.Assuming that there is no rotational deformation at top flange during distortional buckling,and there exists only interactive lateral restraint between the bottom flange and the web,no interactive rotational restraint between them,this paper obtained a simple formula to calculate the elastic buckling stress of the composite beam under uniform bending.For beams distortionally buckled with only one half- wave,a wave length factor is introduced in the formula.Compared with the results of FEM,the proposed formula is -15%～+5%.A effective length factor and equivalent moment factor are introduced to consider the effect of different boundary conditions and moment variation along beam length,based on the FE analysis.
出处
《建筑结构》
CSCD
北大核心
2006年第S1期390-394,398,共6页
Building Structure
关键词
钢-混凝土连续组合梁
畸变失稳
弹性临界荷载
支座影响系数
弯矩放大系数
steel-concrete composite beams
distortional buckling
elastic critical load supporting related-ratio
moment amplification factor
