在节段预制拼装桥梁的墩顶节段，常常采用后浇横隔梁的方式来减轻吊装重量。后浇横隔梁在体量上属于大体积混凝土，混凝土水化热问题会引起一些部位拉应力过大，如控制措施不合理，往往会导致预制梁段在施工阶段的开裂。本文结合南京长江第四大桥的引桥工程，基于三维瞬态温度场理论，利用通用有限元程序ANSYS对墩顶梁段现浇块的水化热效应进行了数值仿真，研究箱梁水化热温度场和应力场的分布规律。分析结果表明，水化热引起的箱梁腹板外侧拉应力水平足以导致混凝土开裂，在水化热测试试验中也观测到了箱梁腹板外侧的纵向微裂缝，与分析相符。在研究水化热温度场和应力场分布规律的基础上，进行了控制水化热温度应力的措施研究，在实桥施工中证实是切实有效的。

For the pier segment of the segmental precast bridge, the diaphragm is often casted in place to reduce the lifting weight. Considering the volume of the diaphragm, it belongs to massive concrete,in which concrete hydration heat may cause excessive tensile stress in some parts. Without right control measures often lead to cracking of the precast segments during the construction phase. Based on three-dimensional transient temperature field theory, numerical simulation with ANSYS was performed, to investigate the distribution law of hydration heat temperature and stress. The analysis shows that, the tensile stress at the outside of the webs is sufficient to lead to concrete cracking, longitudinal micro-cracks along the webs is also observed during the hydration heat test. With the distribution of temperature and stress obtained from numerical simulation, a series of control measures were proposed and adopted to the Fourth Nanjing Yangtze River Bridge approach project, which were proved to be feasible and effective.

孟少平（1960—），男，江苏姜堰市人，教授，主要研究方向为预应力混凝土结构设计理论