Study On Integration And Design For Bridge Long-term Health Monitoring System

It plays a very important role for the national economy and the social security to gain bridge structure characteristic signal scientifically, to evaluate the bridge health condition and to guarantee long-term safe operation. The bridge long-term health monitoring system (BHMS) is a major technique and a key issue to solve the above scientific questions. At present as a result of sensing technology limit, each constituent of the system does not have effective integration, and the system is lack of integrity, long-term and real-time monitoring. This seriously influences its feasibility and application. Along with the breakthrough of the fiber grating sensing technology and its widespread application, it has satisfied the demand of the bridge structure monitoring with great volume, great size, multi-dimensional, multi-parameter in distributed long-term. That indicates the fiber grating sensors have the feasibility in the system monitoring. So BHMS is possible for online long-term monitor. It has meaningful research significance and the application prospective.With basic theory and experiment, project application of the fiber optical technology and the computer technology, this paper studied the fiber optical sensing network and system integration technology for the BMHS based on computing cluster and storage attach network. This will guarantee the bridge multi-parameter, long-term, real-time sensing, transmission, storage and processing. The goal is to establish BHMS in high effective and long-term online monitoring, and to find application in the important engineering construction.By investigation and analysis of BHMS in the domestic and foreign cases, with the actual demand of the large bridge, this paper constructed the high performance fiber grating sensing network using the fiber grating sensor, studied its network construction and the characteristic, and designed the network gathering software. Meanwhile, this paper proposed from three aspects of system hardware, software and database to promote system organic integration, and generate its successful application in many BHMS. The research contents of this full paper include the following several parts:1. Based on the multi-varieties and the large capacity fiber grating sensors, this paper reviewed their application methods and the monitoring goal in the system, and constructed fiber grating sensing network based on field installation of fiber grating sensors for the BHMS. This paper proposed the fiber grating sensing network compsition structure, the sensors choice method in the network, the fiber optical wiring way, the network skeleton and its characterization.2. This paper studied data acquisition software for the fiber grating sensing network monitor by multi-thread technology, and designed its software flow in details. According to the system applicated monitoring sensors, this paper proposed the formula which was used to convert the wave length to the actual physical quantity in detail. With the wireless network, it realized wireless long-distance transmission for the wave length data and the physical quantity.3. This paper integrated a fiber grating sensing network and the electric sensor distribution network to a whole BHMS platform. The electric sensors were installed at the local gathering station. It used the redundant optical fiber network to transmit the data to the central database, and with the system clock synchronization technology, the system used the high performance computation cluster and storage attach network technology to guarantee the data storage and the processing for long-term and real-time online monitoring. The BHMS network communication used the optical fiber self-recovery ring to realize the network self-diagnosis function in order to guarantee long-term reliability of the system.4. This paper designed the software architecture, the flow and the construction characteristic for the long-term BHMS. It proposed the software call each other through the dynamic link library to seamlessly integrate the software subsystem to make the module mutually collaborative work. And it discussed in the software design difficulty and their solutions. At the same time, this paper designed the corresponding database tables separately according to gathering and the relational database melt mutually, it built the integrated database to guarantee the overall system data storage integrity and the data centralized dispatching.5. This paper took Wuhan Yangtze 2nd River as a project example to construct the BHMS. It realized the design of the fiber sensing network and software system. By analyzing the data of the system gathering and processing, validated the integrated system with high effective, the long-term characteristic and online monitoring.