Research of real-time monitoring system for mooring bollard structure safety

The existing safety monitoring approaches for bollard structures is primarily to compare the mooring force measured with the allowable mooring force, which cannot completely meet the requirements of safety monitoring of bollards. Hence a new monitoring approach based on the mechanical characteristics of bollards is proposed and a monitoring interface is developed to display the safety status of the bollards in this paper. Firstly, according to analyzing the mechanical characteristics of bollard structure，the most unfavorable mooring condition that makes bollard the maximum stress under same mooring force is found out. Secondly, a safety evaluation approach of bollards structure is put forward, which regards the maximum strain calculated by finite element method as the safety threshold and classifies the safety levels according to it. Finally, the safety monitoring interface is developed by using Matlab GUI, which can display the safety status information of the bollards in real time. Carrying out the field experiments in Zhenhai harbor, FBG sensors are installed at the specified measuring points of the bottom of the 550KN cast iron bollard, and that measured strains are compared with the safety threshold so as to judge the bollard safety status, and its safety status is displayed in the GUI interface. The system takes strain value as evaluation index, establishes the communication between the FBG demodulation equipment and Matlab by UDP protocol, and displays it in the Matlab GUI interface, which has good accuracy and maneuverability and has positive significance in ensuring the safety of ships, mooring bollards and dock workers.