Gradually-skein Reinforcement Technology For Reinforced Concrete Rib Arch Bridge And Its Application

Arch bridge is the main type among the bridges in service on western highway,especially the large-span flat arch bridges across the river and ravine have occupied a large proportion.This kind of bridge has a certain force tendency like beam bridges due to its gravity,however,the reinforcement technology research has large difficulties in bridge reinforcement project,even to be an urgent task to tackle.Accordingly,it is significant and urgent to construct the evaluation index system of large span arch bridge.According to the research and assessment on the reinforcement effect of the reinforced concrete rib arch bridge using progressive sleeves,this paper introduces the mechanism,design calculation method and construction technology;puts forward the post evaluation strength and stiffness index of the bridge after strengthening the bridge combined with static load test and engineering examples to verify.The main research contents include:①Based on the lateral load distribution,cross section,the stage-stacking stress and fracture mechanics mechanism,combined with limit state design method,the design theory and method of progressive sleeves on the large span flat arch bridge are analyzed and at the same time,the construction technology of the strengthening technology is introduced in this paper.②Based on the strength,rigidity of the structure and the alteration of the two factors before and after reinforcement,the evaluation index system of the strengthening effect of large span flat arch bridge is established:according to the change of the bearing capacity of the structure,constant load stress,the increase of the load and the live load change and the stress level of the strengthened layer,four indexes are presented——bearing capacity increase rateαL(或αL’)、constant load stress change rateαD、load substitution rateαT、reinforcement layer utilizationαM,and the engineering significance and function of the four indexes are discussed.③According to the measured data of static load test,the method of modifying the actual effect of bridge reinforcement is proposed by using the coefficientξD to modify the individual index;based on the same idea,a new evaluation index system for the evaluation of the effect of large span arch bridge is put forward.At last,the reinforce technology of progressive sleeves is applied to the engineering practice of the Guanerzui bridge.Combined with the static load test data of the whole bridge,the strength and stiffness evaluation index of the combined load test are presented in this paper.The results show that the evaluation index system is feasible and effective.