Traditional bridge monitoring systems often require wired connections between sensors,a data acquisition system,and data center.The use of extension wires,conduits,and other costly accessories can dramatically increas...Traditional bridge monitoring systems often require wired connections between sensors,a data acquisition system,and data center.The use of extension wires,conduits,and other costly accessories can dramatically increase the total cost of bridge monitoring.With the development of wireless technologies and the notable cost benefits,many researchers have been integrating wireless networks into bridge monitoring system.In this study,a wireless bridge monitoring system has been developed based on the Sub-1 GHz network.The main functional components of this system include sensors,wireless nodes,gateway and data center.Wireless nodes can convert analog signals obtained from the sensors to digital signals,then transmit the collected data to the gateway using the Sub1 GHz network.The gateway receives and sorts data from different wireless nodes and then forwards these data to the data center wirelessly.All collected data are processed in the data center using the data processing software developed in this study.In order to validate the performance of the wireless system developed in this study,a steel girder bridge was monitored in the field during the concrete deck construction.The field results were also compared with the theoretical values obtained from finite element models to ensure the accuracy and reliability of the wireless system.The results indicate that the wireless bridge monitoring system developed in this study is effective and affordable.The Sub-1 GHz network can be a better solution for bridges with complicated site conditions because of the extended data transmission distance.Although the power consumption can be controlled by using low-power consumption components,including the power control in software design can also dramatically reduce the system’s power consumption.展开更多
A jointless bridge could fundamentally eliminate vulnerable deck joints, thereby meeting the need for sustainable development of bridges, especially for an expressway with highspeed traffic. In this paper, one jointle...A jointless bridge could fundamentally eliminate vulnerable deck joints, thereby meeting the need for sustainable development of bridges, especially for an expressway with highspeed traffic. In this paper, one jointless bridge(deck-extension bridge) with a small box girder in an expressway was chosen as a case study to examine the structural design,construction and field test. The field tests of the bridge indicated that the designed and constructed structures can satisfy the requirement for service performance of the deckextension bridge. Some key technologies, such as the position of longitudinal reinforcements in the superstructure-approach slab connections and the arrangement of the sliding material layers, were introduced. The longitudinal thermal movement of the superstructure in the deck-extension bridge with a small box girder could be predicted accurately by using the average temperature of the cross section of a small box girder. The finite element model, built by using the MIDAS program, was used to analyze the temperature distribution on the cross section of a small box girder, the accuracy of which could be verified by comparing with the measured values. The maximum longitudinal thermal movement of the superstructure in deck-extension bridges with a small box girder under historically extreme temperature conditions was predicted.展开更多
This paper deeply analyses the influence of different local tectonic on stress performance of spatial curved steel box Girder Bridge, using the finite element analysis software to establish space finite element model ...This paper deeply analyses the influence of different local tectonic on stress performance of spatial curved steel box Girder Bridge, using the finite element analysis software to establish space finite element model of this bridge, calculation and analysis were made on the bridge of the strength, stiffness. It has certain reference value for guiding engineering design, have a good foundation for the mechanical properties and stability of linear and nonlinear further study of curved steel box girder.展开更多
Steel and steel-concrete composite girders are two types of girders commonly used for long-span bridges. However, practice has shown that the two types of girders have some drawbacks. For steel girders, the orthotropi...Steel and steel-concrete composite girders are two types of girders commonly used for long-span bridges. However, practice has shown that the two types of girders have some drawbacks. For steel girders, the orthotropic steel deck (OSD) is vulnerable to fatigue cracking and the asphalt overlay is susceptible to damage such as rutting and pot holes. While for steel-concrete composite girders, the concrete deck is generally thick and heavy, and the deck is prone to cracking because of its low tensile strength and high creep. Thus, to improve the serviceability and durability of girders for long-span bridges, three new types of steel-UHPC lightweight composite bridge girders are proposed, where UHPC denotes ultra-high performance concrete. The first two types consist of an OSD and a thin UHPC layer while the third type consists of a steel beam and a UHPC waffle deck. Due to excellent mechanical behaviors and impressive durability of UHPC, the steel-UHPC composite girders have the advantages of light weight, high strength, low creep coefficient, low risk of cracking, and excellent durability, making them competitive alternatives for long-span bridges. To date, the proposed steel-UHPC composite girders have been applied to 14 real bridges in China. It is expected that the application of the new steel-UHPC composite girders on long-span bridges will have a promising future.展开更多
为了改善目前常用的钢箱梁铺装柔性铺装在使用过程中容易出现铺装层开裂、脱粘、车辙、坑槽等病害的问题,结合成都市东西城市轴线绕城高速节点钢箱梁桥工程,对常用的钢箱梁柔性铺装和刚性铺装(45 mm超高韧性混凝土+50 mm SMA铺装和钢纤...为了改善目前常用的钢箱梁铺装柔性铺装在使用过程中容易出现铺装层开裂、脱粘、车辙、坑槽等病害的问题,结合成都市东西城市轴线绕城高速节点钢箱梁桥工程,对常用的钢箱梁柔性铺装和刚性铺装(45 mm超高韧性混凝土+50 mm SMA铺装和钢纤维混凝土+沥青混凝土铺装)进行分析,对比不同铺装形式下桥面板的刚度、主梁应力和单位面积造价。结果表明:采用钢纤维混凝土+沥青混凝土铺装方案,可以改善桥面板局部受力状况,降低钢桥面疲劳开裂及铺装层开裂、车辙等风险,降低工程造价。展开更多
文摘Traditional bridge monitoring systems often require wired connections between sensors,a data acquisition system,and data center.The use of extension wires,conduits,and other costly accessories can dramatically increase the total cost of bridge monitoring.With the development of wireless technologies and the notable cost benefits,many researchers have been integrating wireless networks into bridge monitoring system.In this study,a wireless bridge monitoring system has been developed based on the Sub-1 GHz network.The main functional components of this system include sensors,wireless nodes,gateway and data center.Wireless nodes can convert analog signals obtained from the sensors to digital signals,then transmit the collected data to the gateway using the Sub1 GHz network.The gateway receives and sorts data from different wireless nodes and then forwards these data to the data center wirelessly.All collected data are processed in the data center using the data processing software developed in this study.In order to validate the performance of the wireless system developed in this study,a steel girder bridge was monitored in the field during the concrete deck construction.The field results were also compared with the theoretical values obtained from finite element models to ensure the accuracy and reliability of the wireless system.The results indicate that the wireless bridge monitoring system developed in this study is effective and affordable.The Sub-1 GHz network can be a better solution for bridges with complicated site conditions because of the extended data transmission distance.Although the power consumption can be controlled by using low-power consumption components,including the power control in software design can also dramatically reduce the system’s power consumption.
基金supported by National Natural Science Foundation of China(grant numbers 51508103,51778148,51578161)Recruitment Program of Global Experts Foundation(grant number TM2012-27)
文摘A jointless bridge could fundamentally eliminate vulnerable deck joints, thereby meeting the need for sustainable development of bridges, especially for an expressway with highspeed traffic. In this paper, one jointless bridge(deck-extension bridge) with a small box girder in an expressway was chosen as a case study to examine the structural design,construction and field test. The field tests of the bridge indicated that the designed and constructed structures can satisfy the requirement for service performance of the deckextension bridge. Some key technologies, such as the position of longitudinal reinforcements in the superstructure-approach slab connections and the arrangement of the sliding material layers, were introduced. The longitudinal thermal movement of the superstructure in the deck-extension bridge with a small box girder could be predicted accurately by using the average temperature of the cross section of a small box girder. The finite element model, built by using the MIDAS program, was used to analyze the temperature distribution on the cross section of a small box girder, the accuracy of which could be verified by comparing with the measured values. The maximum longitudinal thermal movement of the superstructure in deck-extension bridges with a small box girder under historically extreme temperature conditions was predicted.
文摘This paper deeply analyses the influence of different local tectonic on stress performance of spatial curved steel box Girder Bridge, using the finite element analysis software to establish space finite element model of this bridge, calculation and analysis were made on the bridge of the strength, stiffness. It has certain reference value for guiding engineering design, have a good foundation for the mechanical properties and stability of linear and nonlinear further study of curved steel box girder.
基金The authors would like to thank the following funders for providing support to this research: the National Key Research and Development Program of China (No. 2018YFC0705400)the National Natural Science Foundation of China (Grant Nos. 51778223 and 51708200)the Major Program of Science and Technology of Hunan Province (No. 2017SK1010).
文摘Steel and steel-concrete composite girders are two types of girders commonly used for long-span bridges. However, practice has shown that the two types of girders have some drawbacks. For steel girders, the orthotropic steel deck (OSD) is vulnerable to fatigue cracking and the asphalt overlay is susceptible to damage such as rutting and pot holes. While for steel-concrete composite girders, the concrete deck is generally thick and heavy, and the deck is prone to cracking because of its low tensile strength and high creep. Thus, to improve the serviceability and durability of girders for long-span bridges, three new types of steel-UHPC lightweight composite bridge girders are proposed, where UHPC denotes ultra-high performance concrete. The first two types consist of an OSD and a thin UHPC layer while the third type consists of a steel beam and a UHPC waffle deck. Due to excellent mechanical behaviors and impressive durability of UHPC, the steel-UHPC composite girders have the advantages of light weight, high strength, low creep coefficient, low risk of cracking, and excellent durability, making them competitive alternatives for long-span bridges. To date, the proposed steel-UHPC composite girders have been applied to 14 real bridges in China. It is expected that the application of the new steel-UHPC composite girders on long-span bridges will have a promising future.
文摘为了改善目前常用的钢箱梁铺装柔性铺装在使用过程中容易出现铺装层开裂、脱粘、车辙、坑槽等病害的问题,结合成都市东西城市轴线绕城高速节点钢箱梁桥工程,对常用的钢箱梁柔性铺装和刚性铺装(45 mm超高韧性混凝土+50 mm SMA铺装和钢纤维混凝土+沥青混凝土铺装)进行分析,对比不同铺装形式下桥面板的刚度、主梁应力和单位面积造价。结果表明:采用钢纤维混凝土+沥青混凝土铺装方案,可以改善桥面板局部受力状况,降低钢桥面疲劳开裂及铺装层开裂、车辙等风险,降低工程造价。
