Study Of Reinforcing Superstructure Of Bridges By Using Shotconcrete

To reinforce superstructure of old bridges, concerning different practical conditions, methods for reinforcement are diversified. Reinforcement using shotconcrete has many advantages, such as instant and convenient construction, early strength of the concrete, no needs for formworks and vibration, etc. By using this reinforcement method, the bearing capacity of the bridge structure can be improved and the monolithic action of the structure can be enhanced as well. But at present, the reinforcing technique with shotconcrete has some problems as below:The reinforcement effect of shotconcrete has not been tested well.The felt reliability between fresh and old concrete and their coordination have been left for further study;As the lower strength of shotconcrete, it is difficult to control the construction quality;Because of the high rebound ratio of shotconcrete, the construction cost is always high enough.Based on the practical project, aiming at the above-mentioned problems, main research works of this paper are below:Expatiate the reinforcement principles of shotconcrete, and test the reinforcement effect;Analyse the reasons for lower compression strength of shotconcrete, and put forward controlling measures for shotconcrete construction quality;Analyse the reasons for higher rebound ratio of shotconcrete, and bring forward the solving methods.In this thesis we first analyze the principle of reinforcement method with shotconcrete, then we validate the feasibility and applicability of reinforcing bridge with shotconcrete through experiments in lab, finally, we summarize the construction measures according to the practical projects. We also analyze the causes lead to the low strength and high rebound ratio of shotconcrete, and then put forward some measures for quality control and construction cost control.The main research conclusions are below:1. The principle of reinforcing bridge with shotconcrete is to widen the section. The loading test results indicate the carrying capacity of bridge is improved obviously. The old concrete and the new concrete are integrated to support theloading.2. The compressive strength of shotconcrete is an important index to judge the construction quality. And all these operations including unsuitable construction, wrong raw materials selection and wrong mix design will have a bad effect on the compressive strength of shotconcrete.3. Decreasing the rebound ratio is an important approach to reduce the construction cost. The factors that affect the rebound ratio include the wind pressure, water pressure and water cement ratio, etc. Additionally, the scientific particular construction plan is also an important measure for the construction cost controlIn a word, using shotconcrete to reinforce superstructure of bridges is a new and efficient construction technology. The content studied in this paper can be used for reference in the construction in the future.