PARAMETRIC OPTIMIZATION OF THE STRENGTHENING OF GULFPORT 230KV TRANSMISSION STRUCTURES WITH GLASS FIBRE REINFORCED POLYMER (GFRP) WRAP

摘要

Gulfport-type wood structures are used to support 1600 km of 230 kV electrical transmission lines in Northern Ontario. Due to the deterioration of the wood elements, these structures have been recognized as a major risk to the safety of the transmission lines. The total replacement of these structures is very costly due to their remote location, and hence an in-service strengthening system is highly desirable. GFRP wrap has been chosen as a light weight, durable, and efficient strengthening system that can be applied to in-service structures to strengthen the critical sections of deteriorated elements. This paper presents a parametric analysis of the variables involved in the proposed strengthening system using Taguchi Method and Analysis of Variation (ANOVA). An Orthogonal Array (OA-8) was used to investigate the effect of four factors and two of their interactions on the effectiveness of the strengthening system. The following factors were considered in this parametric analysis: the extent of surface deterioration, width of wrap, use of filler material and sanding the surface. Two response variables were analyzed as part of the same experimental design: the maximum load and the maximum deflection. Each response variable was analyzed separately using ANOVA and the effect of each variable, including its percent contribution, was specified with corresponding confidence levels. Statistical tools were used to estimate the projected maximum load at a specified level of confidence using the optimum configuration that was obtained from ANOVA results.