Ground penetrating radar (GPR) and the portable seismic property analyzer (PSPA) have been extensively used in the past two decades for monitoring, quantifying, and mapping the deterioration of bridge decks. Using PSP...Ground penetrating radar (GPR) and the portable seismic property analyzer (PSPA) have been extensively used in the past two decades for monitoring, quantifying, and mapping the deterioration of bridge decks. Using PSPA and GPR ensures regular monitoring of bridge conditions, leads to the early detection of deterioration. This research is to address the condition of August A. Busch bridge deck owned by the Missouri Department of Conservation. Visual inspection, GPR, and PSPA data were acquired on the bridge deck. Over 90% of the bridge deck was in fair to good condition with an average compressive strength of over 2500 psi. GPR data showed no indication of significant deterioration. The overall bridge deck was determined to be in fair to good condition.展开更多
In this paper,a dynamic linear detecting method,that the non-linear coefficient NL% was led and the non-linearity of data were estimated continuously and dynamically and determined when NL% exceeded reference value (...In this paper,a dynamic linear detecting method,that the non-linear coefficient NL% was led and the non-linearity of data were estimated continuously and dynamically and determined when NL% exceeded reference value (5%),was used for data processing and could solve the problem caused by the phenomenon of substrate depleting occurred following the redox reaction in portable blood sugar analyzer.By contrast to the conventional end-point method,the dynamic linear detecting method is based on multipoint data collecting.Experiments of measuring the calibration glucose solution with 8 various concentrations from 50 mg/dl to 400 mg/dl were carried out with the analyzer developed by our group.The linear regression curve,whose correlation for the data was 0.9995 and the residual was 2.8080,were obtained.The obtained correlation,residual, and the computation workload are all fit for the portable blood sugar analyzer.展开更多
Falling weight deflectometer(FWD)tests have gained increasing popularity in evaluating the stiffness modulus of a pavement subgrade.This paper presents an enhanced method for in-situ testing and evaluation of subgrade...Falling weight deflectometer(FWD)tests have gained increasing popularity in evaluating the stiffness modulus of a pavement subgrade.This paper presents an enhanced method for in-situ testing and evaluation of subgrade moduli using FWD apparatus.The method comprises three components:1)guidelines for conducting field FWD tests with appropri-ate loading magnitudes and repetitions;2)selection of optimal deflection positions for modulus back-calculation;and 3)determination of the suitable depth of the semi-infinite rigid layer.This method was developed based on measurements and analysis of FWD data from five highway subgrade sites,covering various subgrade soil types and cli-matic conditions.The enhanced method helps to promote the robustness and accuracy of modulus back-calculation results.Furthermore,to validate the proposed method,the back-calculated modulus was compared with moduli obtained from the other two commonly used tests,named the portable seismic pavement analyzer(PSPA)modulus test and the tri-axial modulus test.Comparison results indicate strong correlations between the modulus values obtained from the proposed method and those from the PSPA and triaxial modulus tests,affirming the practicality of the proposed method in determining subgrade stiffness moduli.展开更多
文摘Ground penetrating radar (GPR) and the portable seismic property analyzer (PSPA) have been extensively used in the past two decades for monitoring, quantifying, and mapping the deterioration of bridge decks. Using PSPA and GPR ensures regular monitoring of bridge conditions, leads to the early detection of deterioration. This research is to address the condition of August A. Busch bridge deck owned by the Missouri Department of Conservation. Visual inspection, GPR, and PSPA data were acquired on the bridge deck. Over 90% of the bridge deck was in fair to good condition with an average compressive strength of over 2500 psi. GPR data showed no indication of significant deterioration. The overall bridge deck was determined to be in fair to good condition.
文摘In this paper,a dynamic linear detecting method,that the non-linear coefficient NL% was led and the non-linearity of data were estimated continuously and dynamically and determined when NL% exceeded reference value (5%),was used for data processing and could solve the problem caused by the phenomenon of substrate depleting occurred following the redox reaction in portable blood sugar analyzer.By contrast to the conventional end-point method,the dynamic linear detecting method is based on multipoint data collecting.Experiments of measuring the calibration glucose solution with 8 various concentrations from 50 mg/dl to 400 mg/dl were carried out with the analyzer developed by our group.The linear regression curve,whose correlation for the data was 0.9995 and the residual was 2.8080,were obtained.The obtained correlation,residual, and the computation workload are all fit for the portable blood sugar analyzer.
基金funded by the National Natural Science Foundation of China(Nos.52272323 and 52108412)the Research Project of Shanghai Transportation Commission(No.JT2022-KY-001)the project from the Hebei Provincial Department of Transportation’Science and Technology(No.JX-202001).
文摘Falling weight deflectometer(FWD)tests have gained increasing popularity in evaluating the stiffness modulus of a pavement subgrade.This paper presents an enhanced method for in-situ testing and evaluation of subgrade moduli using FWD apparatus.The method comprises three components:1)guidelines for conducting field FWD tests with appropri-ate loading magnitudes and repetitions;2)selection of optimal deflection positions for modulus back-calculation;and 3)determination of the suitable depth of the semi-infinite rigid layer.This method was developed based on measurements and analysis of FWD data from five highway subgrade sites,covering various subgrade soil types and cli-matic conditions.The enhanced method helps to promote the robustness and accuracy of modulus back-calculation results.Furthermore,to validate the proposed method,the back-calculated modulus was compared with moduli obtained from the other two commonly used tests,named the portable seismic pavement analyzer(PSPA)modulus test and the tri-axial modulus test.Comparison results indicate strong correlations between the modulus values obtained from the proposed method and those from the PSPA and triaxial modulus tests,affirming the practicality of the proposed method in determining subgrade stiffness moduli.
