Executive Summary : | Objective: Latticed towers formed by connecting main members with small size diagonal members. The diagonal bracing system makes these structures stronger/stable against lateral loads. The overall system is very lightweight as compared to the other structural systems where dead weight is predominant and hence finds application in wind resisting structural systems e.g. Transmission Line (TL) towers etc. As the predominant load for these structures is mainly due to wind, which is by its nature dynamic it may therefore excite a structure at its natural frequency and normally induces vibrations at the structure’s natural frequencies. These vibrations produce fluctuating stresses that lead to fatigue damage accumulation and even cause structural failure without exceeding design wind actions. The estimation of fatigue damage with respect to the time will help in ensuring safety and stability of latticed towers. In addition, it helps in making the life extension related decisions. Summary: Latticed TL towers are prone to wind induced fatigue damage over a period of time due to which the functionality of the system will affect significantly. In this context, it is essential to estimate the wind loads on TL towers and to carry out the investigations on TL tower members, connections and sub-structural systems to understand their behaviour under cyclic loading. Development of remaining life assessment methodology for TL tower subjected to wind induced fatigue damage is of paramount interest for safe and reliable operations of TL. Hence, systematic experimental and numerical studies proposed for numerical simulation of wind loads and studies on the fatigue damage behaviour for TL tower members, connections and sub-structural systems. These studies will lead to the development of remaining life assessment methodology for TL towers under low cycle fatigue. |