The internal information of pavement structure is difficult to be accurately obtained by mechanical theory due to the multimedia of component materials and the complex interfacial contacting conditions,and the lab tes...The internal information of pavement structure is difficult to be accurately obtained by mechanical theory due to the multimedia of component materials and the complex interfacial contacting conditions,and the lab tests are affected by model scale and simplification of loads.Therefore,it is of great significance to accurately obtain the internal information of the structure.The fiber Bragg grating(FBG)sensing technology has thus been adopted to monitor the long-term information of temperature fields and temperature variation induced strain inside the pavement structure.Based on the long-term monitoring data,statistical analysis aided with regression algorithms has been performed to establish the temperature prediction model at each depth of the cement concrete pavement.The results show a high quadratic polynomial correlation between pavement temperature and pavement depth.To confirm the effectiveness of the proposed models and techniques,finite element simulation analysis based on ABAQUS software is performed.The feasibility and accuracy of the developed pavement monitoring system for long-term continuous structural health monitoring is proved.The field data indicates that the heat transfer weakening effect due to the structural materials has a gradual lag in the time between the peaks and valleys of the temperatures at each layer of the structure.By analyzing the temperature variation induced strain field of the pavement structure,certain data references are provided for the preventive maintenance,design and construction of rigid pavement structures.The study provides scientific instructions for assess the performance of the pavement under long-term environmental temperature actions and efficient temperature prediction model for preventive control of the large temperature gradient induced deformation effect in rigid pavements in Gansu Province.展开更多
The load</span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">-</span></span><...The load</span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">-</span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;">response correlation is a great concern for the management and maintenance agency of bridges. Based on both the load test data and the long-term structural health monitoring data, this study aims to characterize the variation in the girder-end longitudinal displacement of a long-span suspension bridge, </span><i><span style="font-family:Verdana;">i.e.</span></i><span style="font-family:Verdana;">, the Zhaoyun Bridge in Guangdong Province of China. The load test provides a valuable chance to investigate the structural deformation in high loading levels, while the structural health monitoring system records the real-time, in-site, and long-term measurements in the normal operational stage of bridges. During the load test, the movement direction of the main girder is found to depend on the relative position of the center of gravity of the girder and the loading vehicles. However, over the period of normal operation, the quasi-static displacement at the ends of the main girder along the bridge axis is dominated by the temperature variations, rather than the traffic loading. The temperature-induced deformation is considerable so it should be filtered out from the structural total responses to highlight the live load effects or the anomalies of the bridge. As a case study, the temperature-displacement baseline model of the Zhaoyun Bridge is established and then utilized to identify the erroneous measurements in the structural health monitoring system. This paper serves as a reference for the structural behavior interpretation and performance evaluation of similar bridges.展开更多
The temperature change caused by hydration leads to early-age cracking in concrete box girder.The early-age cracking risk is further improved with low air temperature and large daily temperature difference,especially ...The temperature change caused by hydration leads to early-age cracking in concrete box girder.The early-age cracking risk is further improved with low air temperature and large daily temperature difference,especially in Northwest China.To fill this gap,a temperature experiment and numerical simulation were performed on an actual concrete box girder segment in Northwest China.The temperature field,thermal stress and cracking risk were analyzed using evolution curves,distribution curves and contours.The key parameters that influence the hydration heat temperature,including the cement hydration heat release,cement content,height-width ratio of web,initial temperature,convective coefficient of top plate surface,were analyzed.An anti-cracking case based on parameters analysis was put forward.The results indicated that the temperature evolution can be divided into three stages:warming,cooling and environment significantly impacting.Along the thickness of each plate,temperature distributed is single peak in the center.Along the width or height,temperature distributed is double peaks at axillary position for the top and bottom plates,and single peak in center for the web.The axillary position and web have high thermal stress and significant cracking risks.The temperature difference of each plate,and the early-age cracking risk can be reduced by effectively adjusting the key parameters.Among these,the former two parameters are the most significant factors.The maximum cracking risk can be decreased by 15.7%for every 50 kJ/kg hydration heat reduction.The maximum cracking risk can be decreased by 13.1%for every 50 kg/m^(3)cement content reduction.展开更多
基金supported by Innovation Foundation of Provincial Education Department of Gansu(No.2024B-005)the Fundamental Research Funds for the Central Universities(No.lzujbky-2024-05)+2 种基金the science and technology Program of Hunan Provincial Department of Transportation(No.202305)Industrial Support Plan Project of Provincial Education Department of Gansu(2025CYZC-003)the Hunan Natural Science Foundation Science and Education Joint Fund Project(2022JJ60109).Special thanks are due to Prof.Jinping Ou and Prof.Zhi Zhou of Dalian University of Technology,and Prof.Youhe Zhou and Prof.Xingzhe Wang of Lanzhou University.The findings and opinions expressed in this article are only those of the authors and do not necessarily reflect the views of the sponsors.
文摘The internal information of pavement structure is difficult to be accurately obtained by mechanical theory due to the multimedia of component materials and the complex interfacial contacting conditions,and the lab tests are affected by model scale and simplification of loads.Therefore,it is of great significance to accurately obtain the internal information of the structure.The fiber Bragg grating(FBG)sensing technology has thus been adopted to monitor the long-term information of temperature fields and temperature variation induced strain inside the pavement structure.Based on the long-term monitoring data,statistical analysis aided with regression algorithms has been performed to establish the temperature prediction model at each depth of the cement concrete pavement.The results show a high quadratic polynomial correlation between pavement temperature and pavement depth.To confirm the effectiveness of the proposed models and techniques,finite element simulation analysis based on ABAQUS software is performed.The feasibility and accuracy of the developed pavement monitoring system for long-term continuous structural health monitoring is proved.The field data indicates that the heat transfer weakening effect due to the structural materials has a gradual lag in the time between the peaks and valleys of the temperatures at each layer of the structure.By analyzing the temperature variation induced strain field of the pavement structure,certain data references are provided for the preventive maintenance,design and construction of rigid pavement structures.The study provides scientific instructions for assess the performance of the pavement under long-term environmental temperature actions and efficient temperature prediction model for preventive control of the large temperature gradient induced deformation effect in rigid pavements in Gansu Province.
文摘The load</span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">-</span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;">response correlation is a great concern for the management and maintenance agency of bridges. Based on both the load test data and the long-term structural health monitoring data, this study aims to characterize the variation in the girder-end longitudinal displacement of a long-span suspension bridge, </span><i><span style="font-family:Verdana;">i.e.</span></i><span style="font-family:Verdana;">, the Zhaoyun Bridge in Guangdong Province of China. The load test provides a valuable chance to investigate the structural deformation in high loading levels, while the structural health monitoring system records the real-time, in-site, and long-term measurements in the normal operational stage of bridges. During the load test, the movement direction of the main girder is found to depend on the relative position of the center of gravity of the girder and the loading vehicles. However, over the period of normal operation, the quasi-static displacement at the ends of the main girder along the bridge axis is dominated by the temperature variations, rather than the traffic loading. The temperature-induced deformation is considerable so it should be filtered out from the structural total responses to highlight the live load effects or the anomalies of the bridge. As a case study, the temperature-displacement baseline model of the Zhaoyun Bridge is established and then utilized to identify the erroneous measurements in the structural health monitoring system. This paper serves as a reference for the structural behavior interpretation and performance evaluation of similar bridges.
基金funded by the Key R&D Plan of Qinghai Province(2023-SF-110)the National Natural Science Foundation of China(52108111)the Special Fund for Basic Scientific Research of Central College of Chang’an University(300102212102)。
文摘The temperature change caused by hydration leads to early-age cracking in concrete box girder.The early-age cracking risk is further improved with low air temperature and large daily temperature difference,especially in Northwest China.To fill this gap,a temperature experiment and numerical simulation were performed on an actual concrete box girder segment in Northwest China.The temperature field,thermal stress and cracking risk were analyzed using evolution curves,distribution curves and contours.The key parameters that influence the hydration heat temperature,including the cement hydration heat release,cement content,height-width ratio of web,initial temperature,convective coefficient of top plate surface,were analyzed.An anti-cracking case based on parameters analysis was put forward.The results indicated that the temperature evolution can be divided into three stages:warming,cooling and environment significantly impacting.Along the thickness of each plate,temperature distributed is single peak in the center.Along the width or height,temperature distributed is double peaks at axillary position for the top and bottom plates,and single peak in center for the web.The axillary position and web have high thermal stress and significant cracking risks.The temperature difference of each plate,and the early-age cracking risk can be reduced by effectively adjusting the key parameters.Among these,the former two parameters are the most significant factors.The maximum cracking risk can be decreased by 15.7%for every 50 kJ/kg hydration heat reduction.The maximum cracking risk can be decreased by 13.1%for every 50 kg/m^(3)cement content reduction.
