框架结构二阶效应实用计算

Practical calculation of second order effect of frame structure

钢筋混凝土框架结构在水平荷载和竖向荷载共同作用下,如考虑二阶效应的影响,计算复杂,实际应用不多.当柱的轴力较大,特别是柱的长细比较大的情况下,二阶效应的影响较大,就引起足够的重视.把一般框架结构柱近似简化成单柱压杆模型,推导出简化计算公式.分析了二阶效应对框架柱弯矩的影响因素,公式中不直接显示水平荷载作用,通过修正系数对其内力进行修正,从而体现二阶效应影响,便于实际应用.

The calculation is complicated with little practical application when considering the second order effect for the reinforced concrete frame structure in horizontal and vertical load. More attention should be paid to the effect of second order when the axial force of the colunm is greater, especially with larger slenderness ratio. The formula was deduced by simplifying the frame structure column into the pattern of single column compression bar. The factors of the moment of the frame structure column under the second order effect were analyzed. The effect of the horizontal load was not directly shown in the formula. The internal force was corrected by using correction coefficient reflecting the second order effect, which is simple to use in application.