新旧混凝土梁横向拼接的收缩徐变效应

为分析混凝土收缩徐变对新旧桥梁拼接的影响,在不考虑梁自重的情况下,采用弹性力学求解法分析了新旧梁横向拼接后新梁的收缩徐变效应,推导了拼接后新梁上的纵向拉应力及拼接处的剪力计算公式。以钢筋混凝土简支T型梁桥的拼接为例,比较了新梁在不同混凝土龄期时与旧梁拼接所产生的纵向拉应力和剪应力,同时还对比了不同环境年平均相对湿度对新梁上纵向拉应力和剪应力的影响。计算结果表明:拼接时新梁混凝土龄期和不同环境年平均相对湿度对拼接结构的受力影响较大,新旧梁拼接设计时须采取相应措施以减少混凝土收缩。

Shrinkage and Creep Effects of Lateral Jointing for New and Old Concrete Beam

In order to analyze the influence of shrinkage and creep on jointing for new and old concrete bridge,long-term shrinkage and creep effects of new beams after jointing for new and old beams were analyzed by elastic mechanical approach without consideration of gravity.Formulas of longitudinal tensile stress of new beams after jointing and shears at jointing position were deduced.Taking jointing for reinforced concrete T-beam bridge as example,longitudinal tensile stress and shear stress due to jointing for new and old beam were compared under different concrete ages and the influences of yearly average relative humidity on longitudinal tensile stress and shear stress at new beam with different environments.Calculating results show that concrete ages of new beam at jointing and yearly average relative humidity with different environments have much influence on jointing structural force,so some measures should be conducted to decrease concrete shrinkage in bridge jointing design.