Cost Analysis Of Concrete Bridge Slabs Based On Fatigue Life

In recent decades,the world record of the number of bridges has been broken by China,and the country’s construction technology has been shocking the whole world.In China,the total number of modern bridges have reached 860,000.For the developing country,traffic will have long-term and sustainable growth,and the vehicle’s load is also one of the main reasons for fatigue damage of a bridge panel.But the biggest problem is that people only pay attention to the initial investment,neglecting the future cost of maintenance;they only consider the owner’s cost,ignoring the social cost of bridges when in use.These have caused a series of problems awaiting repairs,such as steel corrosion,concrete cracking,etc.right after the establishment of the bridge.Other problems include:the cost of later repair is too high,the distribution of maintenance resources is unreasonable,and the foresight is lacking--It’s not conformed to the requirements of the people-oriented,sustainable development of bridge construction.Therefore,the whole life design concept of bridge structure has been paid more and more attention at home and abroad.The bridge deck slab,as a part of the fatigue load such as vehicles,should be taken more to heed,too.However,at present,the cost analysis of bridge life cycle mainly focuses on the whole bridge,lacking research on the components,especially on the seriously damaged deck structures.In this paper,based on the tests of the punching and fatigue failure modes of the five pieces of specimens,the numerical simulation of the punching and cutting failure of the 48 pieces of specimens was conducted using ABAQUS,and the fatigue life time and the total material cost of the bridge decks was studied.The main conclusions are as follows:1)This paper introduces the modeling process of ABAQUS entity element,including the determination of simulation parameters,the definition of component,the definition of material attribute,the assembly of each specimen,the definition of interaction,the definition of load and boundary condition,the choice of element type,and the division of mesh.Through the conclusion in the third chapter,the numerical simulation of two specimens in the experiment is carried out,and it is found that the fitting degree between the test results and the simulation results is high.And then 48 specimens with different parameters are numerically simulated,and the reinforcement ratio is obtained.The relation between compressive strength,slab thickness and punching strength of concrete is calculated.The fitting degree of the formula is good.The simulation results are close and the punching failure strength increases with the increase of the ratio of three parameters.2)According to the unit price of each parameter material given by a certain enterprise,the cost of 51 specimens is calculated,of which 3 are test specimens and 48 are simulated ones.The formulas for calculating the relationship between the ratio of reinforcement,compressive strength of concrete,the amount of design parameters of slab thickness and the total cost of specimen material are obtained.It is found that the total cost of specimen material will increase with the increase of the amount of each parameter.The sensitivity analysis of the design parameters of the three specimens to the total cost of the specimen is carried out,and the result shows that the thickness of the plate has the greatest influence on the total cost of the material.Based on the factor of flushing ratio and the formula of fatigue failure life given by the Civil Engineering Association of Japan,the calculation formula of fatigue failure life is obtained.