WT-SMS-MZ04The portal crane has a bad operating environment, long working time in three shifts, large dispatching load, expensive lifting value, and is a major accident in case of danger. Therefore, it is particularly important to monitor the fatigue on-line safety of the main boom structure of the crane. The main beam of portal crane adopts box type structure or truss structure. When working under heavy load or corrosive environment for a long time, the stress of the main boom structure should be monitored, and the structural safety margin should be analyzed to ensure the safety of the main structure of the crane. The portal crane stress online monitoring system is developed and manufactured according to the structural stress and material strength calculation, which can monitor and display the main boom under various loads in real time1 According to the design safety range, the system can store and export the data. It can analyze the trend of the data from the monitoring station and evaluate the health of the main beam by combining the finite element analysis and the load stress spectrum.