Existing Cast-in-situ Concrete Hollow Slabs Bridge Longitudinal Crack Analysis And Treatment

The Cast-in-situ hollow slabs bridge has characters of definite load conditions,simple structure,convenient construction,low building height,and easy to satisfy the special construction requirements for skew,curved,s-shaped and horn etc.Because of these advantages,it has been widely used.In recent years,with the increase traffic,many bridges in a state of overload use and appeared a lot of diseases and defects,including for integral cast-in-situ hollow slabs bridge.The most prominent disease of cast-in-situ hollow slabs bridge is bottom appearing longitudinal cracks,which always through the bridge span.In order to explore the longitudinal cracking mechanism of cast-in-situ hollow slabs bridge bottom,this paper takes a cast-in-place reinforced concrete hollow slabs bridge of Dongguan local highway X232 line as the backing and studies the influence factors of longitudinal cracking of the plate bottom.In this paper,the main works are as follows:(1)Discusses the performance of concrete material,basic theory of crack,and the crack analysis of reinforced concrete structure model.(2)Through the ANSYSA finite element analysis software,the three-dimensional simulation analysis of the cast-in-place reinforced concrete hollow slabs bridge has carried on the stress and deflection distribution characteristics.And it also analyzed the principal cause of longitudinal cracks of the hollow slabs bridge from combining the bridge inspection with load experiment results.The result shows that the cast-in-situ hollow slabs bridge of the thin-bottom,less-height,large-wide span ratio causes longitudinal cracks easily.Secondly along with the increase of the bottom plate thickness and slabs height,the magnitude of maximum deflection and transverse tension stress decreasing.Thirdly with the increase of width span ratio,the magnitude of maximum deflection and bottom longitudinal tensile stress decreases,and magnitude of the maximum bottom transverse tensile stress increases.The cast-in-situ hollow slabs bridge has large width span ratio and transverse stress characteristic obviously.Also through the identification of the load test,the structural strength and stiffness can not meet the standard requirements.Finally,this paper put forward to reinforce of cross section by pasting steel plate and make use of other prevention and control measures.