A Certain Concrete Bridge Safety Inspection And Research

Certain concrete bridge is took as the research object, which mainly carried out basic inspections and load tests for this concrete bridge in this paper.Through comparative analysis between experimental measurements and finite element calculation of the bridge structure,combined with the corresponding bridge standard requirements,estimating the overall work ability of this concrete bridge.The main contents are as follows.(1)It introduces the basic inspect method of bridge appearance defect, concrete strength and the concrete cover depth of reinforcement,and making a inspection for this concrete bridge.(2)Using Midas/civil finite element analysis software to establish a concrete bridge model, the distribution of the different internal forces is calculated under the city-A level design loads.The calculations shown that the maximum mid-span deflection of the inspected bridge is 4.47 mm, and the maximum positive moment is 1.01 × 104 kN · m.The natural frequencies and vibration cycle of the inspected bridge in regard to the top 5 mode of vibration is calculated by Lancsos subspace iteration method..The base of a bridge model frequency is 2.9025 Hz and the impact coefficient measured is 1.173.(3)Through conduct a static test on certain concrete bridge structures,collecting and comparing the strain and deflection values which under the different load condition with positive load and partial load at the control section bridge with the test value and the model calculation value under static load conditions.Under NO.1 load condition,the average calibration coefficients of strain is 0.82 and the average coefficient of deflection is 0.64.Under NO.2 load condition,the average calibration coefficients of strain is 0.66 and the average coefficient of deflection is 0.62.(4)The dynamic response parameters of a concrete bridge is obtained by pulsating tests,bumping tests and jumping tests.The comparative analysis between experimental measurements from the natural frequency, impact factor and damping ratio and calculated value is conducted according to the test results.The biggest impact coefficient measured is1.079 which less than 1.173 calculated, and the average impact factor is1.066 which accounting for 90.9% of calculate the value. The damping ratio is 0.0358.