Safety Assessment Of Oil Derrick With Damage Under Designed Wind Load

The oil derrick is essential in the process of oil exploration and development.It belongs to high structure,large size and poor stability,even after weak damage,the performance of the structure is easy to change.While the wind load is also one of the main lateral loads of the oil derrick,the damage structure is more prone to catastrophic accidents under the ultimate wind load.Therefore,it is very important to study the safety of damaged oil derrick under the design of limit wind load.According to the structural characteristics of the oil derrick,the wind load shape coefficient,height coefficient were calculated,and the influence of fluctuating wind is treated with wind vibration coefficient.The effect of mean wind and fluctuating wind is combined into equivalent static wind load acting on the structure,and this paper analyzes the mechanical displacement and stress response of oil derrick in 4 kinds of simulated design wind load.The Davenport spectrum is used to describe the power spectrum of the fluctuating wind velocity,using MATLAB to write the simulation program of fluctuating wind velocity,and the fluctuating wind velocity time series is obtained,then,the wind induced vibration response of the oil derrick is analyzed,the displacement time and stress response curves of the fluctuating wind load are obtained and compared with the equivalent wind load results of the static analysis.This paper analyzes several common damage forms of the oil derrick,and makes an equivalent treatment for the local member corrosion of the derrick and the bending of the member.The influence of the local bar corrosion and the bending damage of the bar on the derrick under the design wind load condition is studied.The safety assessment method of oil derrick under wind load is proposed based on the theory of strength and stability.The safety of the derrick is assessed under the condition of good and the local damage of the oil derrick,and the suggestions are put forward for the design and field application of the oil derrick.