都汶高速公路先张法预应力混凝土空心梁板施工技术研究

RESEARCH ON CONSTRUCTION TECHNIQUE OF PRETENSIONED PRESTRESSED CONCRETE HOLLOW BEAM SLAB IN CHENGDU-WENCHUAN EXPRESSWAY PROJECT

预应力混凝土结构,受力和截面刚度比钢筋混凝土合理,以其承受荷载较大及施工技术日臻完善,越来越多地应用在公路和铁路桥梁工程。先张法预应力可用于公路桥梁13m、16m、20m等跨径小于25m的空心梁板。重点对先张法预应力混凝土空心梁板的钢绞线伸长量、钢绞线张拉、混凝土浇筑等关键过程进行深入细致地研究,并对如何处理混凝土中断浇筑及混凝土凝结时间检测的重要意义进行了分析。

Force bearing and sectional rigidity of prestressed concrete structure are more reasonable than those of reinforced concrete. Prestressed concrete structure can bear relatively larger load and has mature construction techniques, so more and more prestressed concrete structures are used in highway, railway and bridge projects. Pretensioned prestressing is applicable to hollow beam slab of highway bridge whose span is less than 25 m. Key processes, such as elongation and stretching of steel strand of pretensioned prestressed concrete hollow beam slab and pouring of concrete, are researched in details. Method to treat interrupted casting of concrete and significance of test on concrete setting time are analyzed.