Identifying Bridges With High Damage Risk Using The Taguchi Test Design Method (Case Study: Concrete Road Bridges in Zanjan Province)

Conducting evaluation studies on the bridges used on the road surface is one of the most important time-consuming and costly processes, especially considering the high number of bridges in Iran, i.e., more than 35 thousand in the whole country and 8658 bridges in Zanjan province. On the other hand, the time and cost of these studies can cause delays in carrying out studies for all bridges and cause irreparable damages due to a lack of proper management of bridge repair and maintenance. Taguchi's test design method is one of the methods that predict the desired combination with the help of statistical and mathematical models, by defining its orthogonal arrays, instead of performing all possible evaluation options, by performing a limited number of evaluations. In this research, based on the Taguchi method, instead of examining 8658 bridges with 13 different criteria, only 27 combinations of the physical characteristics of bridges and atmospheric, climatic and traffic conditions affecting concrete road bridges in 5 main axes of Zanjan province were determined the deterioration indices of bridges with these combinations were calculated.It showed that the combination of bridges with 2-3 times of snow along the axis, 91-100 days of frost during the year, 26-30% of heavy vehicles passing over the bridge and a length of 7.1-12 meters has the highest structure failure index with an estimated average of 76.2725, which will lead to the highest failure risk. This means that this combination has created the highest risk of damage. Also, the most important factor in the failure of bridges is the percentage of passing heavy vehicles compared to the total traffic.