Damage Analysis Of Bridge Expansion Joint And Selection Of Applications

As an important component of the bridge structure, expansion devices mainlywithstand impact of wheel load, exposing to the atmosphere for a long time. Itsworking environment is extremely poor, prone to damage and difficult to repair andreplace. Therefore, the research of expansion devices’ injury in a fatigue vehicle loadsunderlies a certain extent of practical meaning in prolonging the life of the expansiondevice and provide recommendations for the their maintenance and replacement.This paper summarizes the main diseases of module type expansion device isbased on fatigue-destroyed anchoring and load-bearing system, comes to theconclusion that vehicle fatigue loading is the main cause of expansion device damage;taking SD-160module type expansion device destruction of a bridge in Guangdongfor example, through the bridge traffic survey, establishes five different types ofsimplified vehicle load frequency value spectrum, using ANSYS finite elementsoftware to implement load analysis of steel beams of stretching device, thenestimates the fatigue life of the three parts of the dangerous anchorage concrete,welding point of anchoring reinforced with embedded bar and the welded steel beam,the results show the life of anchorage concrete is7.7years, the first to reach the end;the steel beams in considering only the fatigue life of the vehicle under loads is29.3years. Then it analyzes the three major elements which effected on the fatigue life ofexpansion device, the results shows that when the supporting beam spacing increases,the life of the steel beams reduces; greater the strength of concrete anchorage zone,longer the life of concrete itself and welding point of anchoring reinforced withembedded bar; when anchored with elastic resin the life of concrete reaches abouttwice of that of the C50concrete, the life of C40steel fiber concrete and C50concreteanchor match when used in anchoring. The fatigue damage of replacement program ofexpansion device of SD-160bridge is analyzed. Its service life is estimated as6.2years. The author of this paper puts forward proposals Ⅰ which extends1.5years lifeof the steel beams welded point than the original construction plan, the program Ⅱmeans a life span of20.8years, equals to the fatigue life of steel beams with the support beam spacing of1.8m, the research result can be a reference for similarexpansion device replacement project.