Load Test Monitoring And Condition Analysis Research Of The Concrete Simple Supported Double T Bridge

Longer service life of the bridge security has gradually become one of the core issues of road construction bridge infrastructure. Can an objective,reasonable and effective evaluation of the performance of active safety of the bridge,the key issue is to ensure the safe use of the bridge.Taking a longer service life of the 16th-span reinforced concrete double-T bridge to support projects and to carry out a series of health monitoring evaluation,and propose corresponding reinforcement measures.Using observation,records,photographs and other methods,the concrete simply supported each cross member 16 double-T bridge structure was examined by the appearance of defects. According to the corresponding specifications of the test results were evaluated bridge qualified levels,assess the results of Class C,so the bridge need for regular routine maintenance and minor repairs. After sampling found on the bridge of concrete carbonation depth has reached 14.4 mm,but still less than the thicKNess of the protective layer is not caused due to the carbonation of concrete reinforcement corrosion; sample test results of concrete strength estimation value in the range of 31.24 MPa ~ 41.79 MPa Inside. Experimental Methods The half-cell potential of reinforced concrete slab bridge flange within the state of corrosion were detected,the results show that the bridge flange reinforced concrete slab where there is corrosion activity,but the corrosion state of uncertainty,corrosion may occur. Using non-destructive methods of concrete cover thicKNess bridge a sample test results show that the thicKNess of the protective layer of concrete eigenvalues / design values are greater than 0.95.On the bridge dead load experiment measuring the deflection of the bridge across the first and second load 1/4 load deflection at the cross section are 0.9 mm,much larger than the theoretical value of 0.24 mm,calibration coefficients obtained was 3.75; 1/2 deflection at the cross-section respectively 1.5mm and 1.8mm,much larger than the theoretical value of 0.32 mm,calibration coefficients obtained was 5.63; 3/4 deflection at the cross-section were 1.1mm and 1.4mm,much larger than the theoretical value 0.24 mm,calibration coefficients obtained was 5.83. Evaluation of structural rigidity as an important indicator,is generally believed that the structure of deflection calibration coefficients range from 0.7 to 1.0 in the stiffness of the structure to meet the requirements,but the calibration coefficients obtained in this experiment are significantly greater than 1.0,showing the stiffness of the bridge can not meet the requirements of bridges. Using static load test to detect the strain of concrete bridge span in order difference value and the theoretical value of the comparison measurement,using the least squares method to the east and west sides of the web measured concrete strain data were fit linear regression analysis. The results showed that the concrete strain along the beam webs bridge across the east and west sides of the high-profile no longer linear,wherein the height direction along the east side of the web of concrete strain beam both have compressive strain tensile strain,and on the pressure to pull,and theoretical analysis,but on the west side of the web is full of concrete strain compressive strain does not match with the theoretical analysis. This is because the stiffness of the structure of the bridge has been a very serious impairment,capacity can not meet the normal passage of vehicles bridges elastic recovery.The bridge was pulsating experiment,by prior arrangement on the bridge of the acceleration sensor,the acquisition of the bridge vibration data in a natural pulsating signal through the data to give the first natural frequency of the bridge is 7.35 Hz,is less than the theoretical value of 7.72 Hz,showed that the actual working conditions of the bridge is bad. In the barrier-free driving experiments, when more than 20 km/h speed, impact coefficient is larger, and with the impact coefficient increase with the increase of the vehicle speed.Using Dr. Bridge plane frame model, the sixteen span concrete simply supported double-T bridge numerical simulation analysis: calculated Live Load bridge,checking the crack width of the bridge,is a cross-sectional strength and strength of oblique section,and the corresponding reinforcement measures. Through the analysis of test data, it is suggested that to minor repair and maintenance as well as the speed limit on the bridge, to ensure the safety of bridge and vehicle.