悬臂浇筑连续梁竖向预应力张拉质量控制措施-《高速铁路技术》

文章信息/Info

Title:: Quality Control Measures in Vertical Prestress Tensioning for Cantilever Casting of Continuous Girder

Author(s):: HE Yuxian; SINOHYDRO Engineering Bureau 8 Co., Ltd., Changsha 410004, China

Keywords:: cantilever casting|continuous girder|vertical prestress|quality|benefit

摘要:: 随着预应力混凝土结构在铁路桥梁工程领域的普遍应用与推广，预应力钢筋成为减轻结构自重、节约钢材和水泥、增大结构跨度、降低建设成本和防止桥梁开裂等方面不可替代的重要材料。在悬臂浇筑连续梁过程中，竖向预应力体系成为防止预应力混凝土桥梁腹板主拉应力开裂的有效手段。但在施工过程中，竖向张拉超张现象较为明显，数据合格率无法保证，张拉质量也难以控制，给施工带来了极大困扰。针对这种现象，本文通过施工过程中的不断实践，就如何提高悬臂浇筑连续梁竖向预应力张拉质量进行了研究分析，较好地解决了竖向张拉超、欠张以及二次处理等问题。

Abstract:: The prestressed concrete structure is now widely applied for the erection of railway bridges, and the prestressed bar has become an irreplaceable important material in reducing structural dead weight, saving steel and cement, increasing structural span, reducing construction costs and preventing bridge cracking. Meanwhile, the vertical prestressing system has become an effective means during cantilever casting of continuous girder, to prevent the cracking of prestressed concrete bridge web resulting from the main tensile stress. However, there is obvious vertical over-tensioning during construction, so that the data quality cannot be guaranteed, and the tensioning quality is difficult to control, resulting in great trouble to the erection of bridge. In view of this phenomenon, based on the observations in the continuous practice, this paper studies and analyzes how to improve the quality of vertical prestress tensioning for cantilever casting of continuous girder, and effectively solves the problems such as vertical over-tensioning, under-tensioning and secondary treatment.