Study On The Health Monitoring System Of The Small And Medium Bridges Under Operation

With the rapid development of transportation industry in China, more and more bridges appear, and 90 percent of them are small and medium bridges. The small and medium bridges play an important role in the road traffic system. Thus, ensuring their operational safety is significant to traffic condition and socioeconomic development. Currently, manual inspection is widely used in detecting and evaluating the bridges under operation, but safety of the bridges can not be guaranteed for the limitations of this approach. Meanwhile, the traditional bridge health monitoring system is too costly when applying on small and medium bridges.Based on the traditional bridge monitoring technology, the cloud computing technology is introduced in this paper. Then, the construction costs of small and medium bridges monitoring system are reduced and the efficiency of the system deployment is enhanced by using cloud computing technology advantages in cost and efficiency of IT resources.To reduce the construction costs and improve the monitoring efficiency, the cloud computing technology, which based on the traditional bridge monitoring technology, is introduced in this paper.Specific studies are as follows:①The realization of small and medium bridge group monitoring system based on the cloud platform. This part is mainly to give a brief introduction of monitoring system’s architecture and program. In this system, its architecture uses the virtual server instead of traditional physical server, which has a series of advantages, such as the lower costs of hardware, the convenience of software development, the high efficiency and stability of system operation, etc. These advantages make the small and medium bridge operators monitoring can be achieved. Furthermore, this part also describes the components of the system software, which includes an integrated subsystem of bridge, a subsystem of parameter configuration, a subsystem of bridge inspection, a subsystem of data processing and analysis, a subsystem of structural safety evaluation and the user interface subsystem. And then this part illustrates the function of each subsystem.②The technology of small and medium bridge operating conditions evaluation based on the static limited monitoring data. This part introduces the classification of cracks, and the causes and location of cracks, theoretically. Then having a selection of more than 300 small and medium bridges of each type, and also having a statistics on the location and the number of crack, in order to identify position and the type of bridges which are most prone to fracture. Lastly, this part gives the evaluation method, which is based on the multiple data sources.③Sensitivity analysis of sensor to the response of structure. This part, choosing the Xincunzhong bridge as the object, studies on the changes of deflection and strain between each of beam and the deflection and strain of beam itself when the bridge is under the constant loads and when horizontal linkage between beams changes or the carrying capacity of beam drops, respectively. Then it is can be judged that whether the damage can be identified by the monitoring system, relying on the accuracy of the available sensor.④Analysis of data anomalies and temperature effects. This part analyzes the abnormal data and the temperature response of strain monitoring data from June to November 2014. The analysis of abnormal data includes alarm settings, statistics of strain greater than 200με and traffic survey. Temperature response analysis includes relationship between temperature and strain and it also has to find out the deficiencies of temperature correcting by the traditional instruments. Lastly, this part proposed a new correction method, which is based on the least square method, to the temperature correcting.