Analysis of Stresses in Tapered Rectangular Utility Pole

Power transmission is generally carried out through electric cables supported by transmission pole (Utility pole) of various materials and cross sections. However, their utilization depends on climatic conditions and external loads acting on them. The forces comprise of wind pressure, tension in conductors and seismic vibrations due to earthquakes. These loads induce various stresses in the pole like bending, shear, crushing etc. There is a necessity for investigation of these stresses in the existing utility pole subjected to the loads acting on them. The objective of the paper is to study the stresses developed in the tapered rectangular utility pole made of Steel Reinforced Concrete material which is ۸m in total length. The work includes the calculation of stresses in the existing poles made of three grades of concrete (namely M۴۰, M۴۵, and M۵۰), four different load cases of pre stressing (zero or no pre-stress, with a pre-stress of ۵۰%, ۶۰%, and ۷۵% of maximum allowable strength of steel reinforcement), under the effect of ۱۸۵ kmph wind velocity.  Theoretical and FEA of stresses were carried out and the results were compared. The ۳D solid modelling of pole is carried out using SOLIDWORKS and imported into ANSYS ۱۵.۰ for calculation of stresses. It is observed that in either cases of RCC and PSCC, the stresses developed in the concrete cause failure of the pole. However, in case of PSCC, the stresses causing failure are less compared to RCC and may have longer life.

Keywords:

Concrete , FEA , Pre-stress , Utility poles , Wind pressure