Study On Practical Reinforcement Technology And Disposal Decision System For Hollow Slab Bridge

Because of many advantages,the hollow slab was widely used in the reinforced concrete bridge construction in the early days. As the operation time grows, for hollow slab bridges built in the early days, there are many structural diseases, such as hinge joint cracking, longitudinal crack in slab bottom and so on, which are mainly caused by adopting shallow hinge joints, etc. Numerous hollow slab bridges are widely used in the key junction road of our country. Thus, once security risk is produced, there will be incalculable consequences.The hollow slab bridge demolition and reconstruction, not only need a lot of work, time and cost, but also will interrupt the traffic for a long time, causing the huge waste of social resources and greatly affecting the regional economic development. Therefore, in view of various factors causing the fabricated hollow slab bridge diseases, the reasonable and effective strengthening methods are explored to form a safe, economic and applicable hollow slab practical strengthening techniques, and to build strengthening treatment decision-making system easy to master and apply by the maintenance managers. So, the hollow slab bridge bearing capacity and durability can be quickly and efficiently improved, which has important social and economic significance. Based on the hollow slab bridge disease current situation, aiming at a large number of hollow slab bridges strengthening requirements, this paper mainly carries out the research from the following several aspects:① First, the main diseases of the hollow slab bridge are arranged and expounded, focusing on the analysis and research of the main slab disease forms and formation mechanisms, making clear the danger of diseases and the necessity of strengthening.② On the basis of knowing disease mechanism, this paper aims at exploring practical efficient hollow slab bridge strengthening techniques. Respectively from the strengthening principle, design calculation process and construction technology, etc., three promising hollow slab strengthening techniques are studied, including the transverse steel beam method, the transverse prestressing method and composite mortar longitudinal prestressed steel wire rope method. By the finite element software Midas FEA, the prestressed hollow slab bridge models are modeled with typical disease, analyzing the effect of separate key technical indicators on the strengthening for three technologies.③ Based on the above analysis, combined with disease characteristics of a typical 20 m fabricated hollow slab bridge, strengthening design schemes corresponding to three strengthening methods are put forward. By comparing and analyzing, for hollow slab bridge bearing capacity, transverse distribution performance and resistance to cracking, the applicability of three strengthening technologies is obtained.④ Finally, based on the above comprehensive conclusion, the assessment indicator system for the hollow slab bridge is set up, which is about strengthening effect of longitudinal, transverse crack in the slab bottom and hinge joint diseases.Combining with analytic hierarchy process and the theory of fuzzy synthesis evaluation, the hollow slab bridge strengthening disposal decision system is put forward.This will complete the hollow slab bridge strengthening database and provide a reference for experts and calculation in the future to choose the targeted and applied hollow slab bridge strengthening scheme. It is of great social and economic significance and has broad application prospects.