| At present,a large number of prestressed concrete continuous girder Bridges are operated on China’s highway transportation system.During the use of these Bridges,structural damage and material deterioration occurred over time.The deterioration of structure and carrying capacity of the bridge will affect the normal use of the bridge.Serious accidents can lead to major traffic accidents.Therefore,it is very important to study the bearing capacity test and test method.This paper summarizes the evaluation methods of bridge bearing capacity at home and abroad,and further expounds the theory and evaluation process of static load test method and dynamic load test method.Based on the actual project,the concrete bridge bearing capacity method based on load test is applied.By means of static load test,the strain and deflection of each control section under different loads are obtained,and the crack resistance analysis is carried out.Through dynamic load test,including driving test,jumping test,brake test,pulse test,etc.,the dynamic response of bridge is analyzed.The finite element method is applied to calculate and calculate the test bridge accurately.The measured value and theoretical calculation value of the load test are compared and analyzed.The following conclusions are drawn:(1)the calibration coefficients of bridge stress and deflection meet the requirements of test specification.It shows that the superstructure(bridge deck pavement and anti-collision wall)is involved in the structural stress,and the safety reserve of the structure is increased.It is found that the structure under load is in good elastic working condition.The strain change of each measuring point in the tensile zone is normal.After careful inspection,the concrete under the maximum load is not cracked.The structural deformation meets the requirements of test specification and the structural rigidity meets the requirements of design specification.The measured residual deflection is small and the overall deformation of the structure is elastic.(2)the bridge driving test measured the vibration frequency of the bridge as 2.64 Hz,3.51 Hz,4.64 Hz and 5.08 Hz.In the driving test,the maximum amplitude of the single vehicle was 0.53 mm,the maximum dynamic displacement was 1.11 mm,and the maximum impact coefficient was 0.25.The bridge brake test measured the vibration frequency of the bridge as2.54 Hz,3.66 Hz and 5.08 Hz,and the maximum response amplitude of the bridge vertical bridge was 0.48 mm.The bridge jumping test measured the vibration frequency of the bridge from 2.59 Hz,3.61 Hz,4.64 Hz,5.08 Hz,and the maximum vibration amplitude of the jumperwas 0.31 mm.The vibration frequency of the bridge is 2.62 Hz,3.52 Hz,4.57 Hz and 5.08 Hz.The measured values of natural frequencies are greater than the theoretical values,indicating that the actual stiffness of the bridge structure is large. |
