摘要
结合两座实桥的裂缝观测和有限元分析的结果 ,研究了大跨径变截面预应力混凝土连续箱梁桥的抗裂性能。首先 ,对引起箱梁开裂的主要因素如纵向预应力束布置方式、竖向预应力大小、温度梯度模式等进行了敏感性分析。从预应力筋布置、温度梯度模式的选取、混凝土拉压应力的限值、非预应力筋的设置等几方面提出了抗裂设计改进建议 ,并指出目前用于箱梁计算的平面杆系理论和空间梁格理论的局限和不足。其次 ,在分析常见结构性裂缝及其成因的基础上 ,建议在腹板中加强配制斜筋和箍筋的措施来防治腹板斜裂缝。最后 ,认为纵向预应力束布置方式和竖向预应力大小对箱梁腹板斜裂缝的控制和开展起着主要的作用 ,现行计算支座附近温度应力偏于不安全 ,腹板箍筋应考虑竖向应力影响。
Based on the cracking observation and finite element analysis of engineering projects, properties of cracking resistance in PC continuous box girder bridges are studied. The results obtained from the calculation are presented to demonstrate the effect of sensitive factors, such as the arrangement of longitudinal prestressing tendons, the magnitude of vertical prestressing force, the temperature gradient, etc. Several design recommendations and construction measures about the limited stress of concrete, the reinforcements and some sensitive factors mentioned above are proposed to control cracks. In accordance with the analysis of structural cracks, some conclusions are deduced. The arrangement of longitudinal prestressing tendons and the magnitude of vertical prestressing force take key roles in the cracking control of box girder webs. The prevailing temperature stress calculation has less safety, and the inclined and hoop reinforcements are effective in cracking control of box girder webs.
出处
《浙江工业大学学报》
CAS
2003年第1期22-27,共6页
Journal of Zhejiang University of Technology
基金
浙江省交通科技发展基金资助项目 (2 0 0 133)
