变分原理分析连续箱梁开裂后的剪力滞效应

变分原理通常适用于箱形截面梁剪力滞效应弹性分析,基于换算截面法和解肢法,运用变分原理推导了钢筋混凝土连续箱梁均布荷载作用的剪力滞系数计算公式,考虑了混凝土开裂对连续箱梁剪力滞效应的影响,并与试验结果和规范方法进行了对比。分析表明混凝土开裂将引起连续箱梁剪力滞效应分布规律发生变化,且混凝土开裂对跨中截面翼缘有效分布宽度系数的影响较小,对中间支座截面的影响较大。本文方法力学概念明确,是其弹性分析适用范围的拓展,可广泛应用于连续箱梁开裂后的剪力滞效应分析。

SHEAR LAG EFFECT OF CRACKED CONTINUOUSE BOX GIRDER ANALYSED BY VARIATIONAL PRINCIPLE

Variational principle is usually fit for elastic analysis of shear lag effect in box girder. In this paper, based on transformed-section method and dismemberment method, shear lag coefficient formulas of continuous reinforced concrete box girder under uniform load is derived by means of variational principle, in which concrete cracking is taken into account. The result is compared with test data and that adopted by design code. Analysis showed that concrete cracking would change distribution law of shear lag effect, and its effect is small on the effective width coefficient of flange at mid-span, its effect is big on that at mid-supported section. The method adopted in this paper is definite in mechanical concept, and it is the extension of elastic analysis, it can be widely used in shear lag effect analysis of cracked continuous box girder.