体外预应力加固旧桥的方法和结构组成.rar

体外预应力加固旧桥的方法和结构组成

摘要：本文简要介绍了几种常见的体外预应力进行旧桥加固的形式。
关键词：旧桥加固  体外预应力  加固方法  结构组成

1 用体外预应力加固旧桥的方法
随着我国社会主义事业的飞速发展，我国的道路交通状况也发生了翻天覆地的变化。在大规模高等级公路建设的同时，大量的旧有公路的改造工作也摆在了我们面前。据调查分析，全国的国道、省道和县级公路的永久性大、中性桥梁中，设计荷载达到汽车—20级、挂车—100标准的仅占大、中型桥梁总数的6.53%。随着公路等级的提高，这些低等级桥梁是不能满足承载力要求的。由于受资金和材料资源的限制，这些低等级桥梁是不可能全部拆除并新建，只能投资较少的资金进行加固。我国公路桥梁界的广大工程技术人员对旧桥加固技术进行了大量的研究工作，并提出了许多切实可行的加固方法，例如：加厚桥面铺装层，加焊主筋，增设主梁以及改变桥梁结构体系等。这些技术各自适用于一定的条件和结构，但就钢筋混凝土简支T梁和微弯板组合梁这两种最常用的结构而言，采用体外预应力技术进行加固是一种简单易行且行之有效的方法。用体外预应力加固的方法很多而且效果也很好，下面简要介绍几种常见的体外预应力的加固形式。
1.1 钢拉杆横向收紧加固
如图1所示：这种加固方式为用钢拉杆横向收紧的方法施加体外预应力。在梁的底面以下设置4Φ25mm的16锰钢筋，分两排布置。拉杆在距梁端
External Prestressing Old Bridge and structure of

Abstract: This paper introduces several common external prestressed reinforcement in the form of old bridges.
Keywords: Old Bridge Strengthening Prestressed Reinforcement structure and composition

1 Old Bridge with External Prestressing method
With the rapid development of China's socialist cause, the road traffic situation in China has undergone enormous changes. In the large-scale highway construction, a large number of the transformation of the old highway work was placed in front of us. According to the survey analysis, the country's national, provincial and county roads, a permanent large, neutral bridge, the design load to level vehicle -20, -100 standard trailer only large and medium bridges of the total 6.53%. With the improvement of road grade, these low-level bridge can not meet the capacity requirement. Due to limited financial and material resources, these low-level bridge is not all removed and new, less investment funds can only be reinforced. China Road and Bridge sector, the engineers and technicians of the Old Bridge of done a lot of research and put forward many practical reinforcement methods, such as: thickening of pavement layers, plus welding longitudinal bars, additional main beam and the change Bridge Structure System. Each of these techniques apply to certain conditions and structure, but the reinforced concrete T beams and simply supported composite beams curved board that two of the most common structure, in vitro techniques for prestressed reinforcement is a simple and effective in Methods. Using External Prestressing many ways but also very effective, the following brief description of several common forms of prestressing reinforcement.
1.1 Reinforcing steel rod horizontal tightening
Figure 1: This reinforced steel bar way to exert lateral tightening method of prestressing. The following settings in the bottom beam 16 4Φ25mm manganese steel, arranged in two rows. Rod end of the beam in the distance