Study On Fatigue Performance Of The Old Bridge Corroded Reinforced Concrete Slanting Beams

With the rapid development of economy,a large number of Bridges of reinforced concrete structure have been integrated into modern life,it brings convenience to people and speeds up the economic development of the country.But in the actual operation stages,the reinforced concrete bridge plate often bears repeated action of the auto load,its amount of damage accumulating,its mechanical property declining,the reinforced concrete bridge plate can be destroyed without warning and it is under static load.The actual reinforced concrete structure is also accompanied with the question of steel's corrosion,under the coupling of vehicle load and steel's corrosion,the damage of reinforced concrete structure is intensified,its mechanical degradation is more obvious,it's a serious threat to life and property.The research object of experiment is from QingDao WuShi road,this bridge has been in service for nearly 30 years,some plate beams have serious corrosion of reinforcement,there is no guarantee that bridge will be safe,for safe reasons,some plate beams had been replaced.So far,the researchers have less study of natural rust and concrete beams,in order to solve this situation,In this paper,the fatigue performance test of the natural corroded reinforced concrete slanting beam is carried out,the following aspects are mainly studied:(1)It measures the damage to the plate beam,and it measures concrete strength and calculates the bending of the inclined beams,it Determines load amplitude for the back fatigue test;The grade evaluation of rust steel for three slanting beams.L2,L2,L3 beams' the average corrosion of steel are 1.55 mm ? 1.26 mm ?0.63 mm,all light corrosion;(2)It carries out random variable amplitude cyclic loading for natural corroded reinforced concrete beams,it explores the fatigue property degradation rule,mainly including crack law of development,internal damage rule of plate girder,rule of reinforcement and concrete strain,rule of deformation of plate girder,fatigue life and etc,secondly,the comparison and analysis of three slanting beams with different degrees of rust are analyzed.the study has shown that the fatigue property of the reinforced concrete slab is basically in the three stages of fatigue damage theory,the greater the corrosion degree of reinforcement,the more obvious the fatigue property degradation;(3)It combines with fatigue damage accumulation theory,and analyzes the test data.The results show that the greater the corrosion,the greater the fatigue damage,the greater the growth,the more obvious the degree of rigidity degeneration.