| Large numbers of bridges in our country have defects and damages. It is necessary to maintain, strengthen and rebuild them to guarantee their safety in normal operation. Effective detection and assessment for the old bridges is the precondition of ec-onomical maintenance and strengthening. We can also judge the effect of strengthening and actual load-carrying capacity by another assessment after reinforcement. Taking the Dadu river bridge (reinforced concrete deck arch bridge) in LeShan as an example in this paper, some aspects are discussed and studied as follows:1. The status of detection, assessment and strengthening of bridges at home and abroad is discussed.2. The usual damages and the causes of them for reinforced concrete bridges are summa rized, and the mechanism of reinforced concrete damages is analyzed. The content and methods of detection for reinforced concrete bridges are also presented. The primary assessment methods at home and abroad are introduced.3. Taking a real bridge as an example, introducing the content of detection, and its main damages are analyzed. According to the results of detection, technique state of the bridge are assessed comprehensively by point method. According to the design specifications, the load-carrying capacity of the bridge is assessed to provide referen-ces for maintenance and strengthening.4.Usual strengthening methods for superstructure and substructure of bridges are introduced, and the principle of strengthening and design is presented. On the basis of the damages of the real bridge, strengthening method is introduced, and the reason why this method is selected is analyzed.5. Firstly, according to the results of the load test, the effect of strengthening is analyzed and assessed. Then, the finite element model is modified to evaluate the carrying capacity of the key sections. At last, by comparing the assessment results before and after strengthening, the rationality of the strengthening methods for this bridge is checked. |
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