基于应力控制箱梁截面设计数值模拟分析

Numerical Analysis of the Box Girder Sectional Design Based on Stress Control

为了研究箱梁截面尺寸对箱梁力学行为的影响,分别以梁高、顶板、腹板及底板为参数,通过建立有限元模型,分析了各参数变化对箱梁应力变化的影响及敏感性.分析结果表明,随着顶板厚度的增大,箱梁顶板横向拉应力逐渐减小,箱梁顶板适宜厚度为24~36 cm;随着腹板厚度的增加,箱梁斜截面主拉应力逐渐减小,墩顶截面腹板的适宜厚度约为跨径的1/260~1/170,支座截面腹板的适宜厚度为墩顶截面腹板厚度的1/2.0~1/1.6;随着顶板厚度的增加,墩顶截面底板压应力也呈逐渐减小趋势,墩顶截面底板的适宜厚度约为跨径1/220~1/140,跨中截面底板的适宜厚度为20~31 cm.最后,建议在箱梁结构设计时,应通过整体分析、局部分析综合考虑各因素来确定其最优设计参数,以提高箱梁的承载能力和抗裂性能.

In order to study the mechanical behavior of the beam caused by different box girder section size,this paper establishes the finite element model and analyzes the sensitivity of stress condition under different parameters,such as height of beam,top deck,bottom slab and web.The analysis result shows that the transverse tensile stress,the oblique section principal tensile stress and the compressive stress of bottom slab decrease with the increase of thickness of the top deck,web and bottom slab.The result also indicates that the reasonable thickness of the top deck is within 28 cm^32 cm and the reasonable thickness of the web and bottom slab situated at pier section is respectively 1/260～1/170 and 1/220～1/140 times as the main span.The reasonable thickness of the web and bottom slab situated at middle span section is respectively 1/2.0～1/1.6 times as pier section＇s and within 20 cm^31 cm.Suggestion is given that the integral and partial analysis should be adopted in the design of the section size,so as to improve the bearing capacity and crack resistance.