摘要
介绍国内外几种典型规范的温度梯度计算模式,并根据箱梁常用截面尺寸范围,推导出相应的温度梯度解析表达式。以广州某预应力混凝土箱梁桥为工程实例,根据现场试验测试数据的分析,对3种折线模式的温度梯度提出相应的曲线型改进模式。根据国内外几种典型规范的温度梯度计算规定和本文提出的相应改进温度模式分别计算实例桥梁结构在各种温度梯度作用下引起的内力分布和变形。对比分析与计算结果表明:提出的温度模式可以简化计算程序,计算所得的截面最大拉应力略大于规范模式的相应结果,这有利于箱梁的裂缝控制;截面的最大拉应力出现在箱梁顶板的底面位置;桥墩边缘截面的温度应力大于跨中截面的温度应力;在现行设计规范的温度梯度作用下,箱梁截面的最大拉应力可能大于混凝土的抗拉强度,设计中应采取裂缝预防措施。
Several typical temperature gradient models in different national design codes were briefly introduced.Formulas for the typical code temperature gradient models were derived according to commonly used dimensions of concrete box girders.A prestressed concrete box girder bridge in Guangzhou was adopted as an engineering example.Based on the measured data analysis of bridge,three modified curvilinear temperature gradient models for box girders were proposed to replace the corresponding broken line models.Distributions of internal forces and deflections caused by temperature effect were computed based on the proposed models as well as the typical models in the codes respectively.The results show that compared with the broken line model,the evaluation procedure can simplify by the proposed curves.As for the computation results,the maximum tensile stresses in cross sections are a little bigger than those given by the model of the codes.Therefore,from a design point of view,the results given by the proposed methods are on the safe side.The maximum tensile stress appears on the bottom side of the top plate in a box girder cross section,and that the maximum tensile stress on the edge of the supported section is larger than that on the mid-span section.The maximum tensile stresses induced by temperature effect may be larger than the concrete tensile strength,thus some preventive measures should be taken to avoid temperature cracking.
出处
《中南大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2010年第6期2360-2366,共7页
Journal of Central South University:Science and Technology
基金
国家科技支撑计划项目(2006BAJ01B07-05)
广东省交通厅科技项目(200536)
关键词
预应力混凝土
箱梁
温度梯度
内力
挠度
prestressed concrete
box girder
temperature gradient
internal forces
deflections
