Evaluation of Babolsar City Bridges in Utilization Case from Risk Taking Point of View Seismically by Using FMEA-FUZZY Method

Bridges with each structural shape and with every kind of materials that are made, soon or late, fatigue effects are appeared in them, among kind and rate of these fatigues and their expansion trend, numerous factors are effective such as climate situation, flood or earthquake occurrence, load increase more than design rate, design qualification and performance and kind of materials. If each of these factors are not considered leads to decrease of useful life in structure. In this research after doing investigations by using FMEA-FUZZY method, it became clear that earthquake is known as the main and the most effective factor of bridges ruin in utilization case. For this reason, imposed earthquake on Babolsar bridges was strictly investigated and after bridges modeling in SAP software, probability of ruination in each structural element of bridges was calculated. Then, by using FMEA-FUZZY method, rate of risk in each bridge against earthquake becomes clear. Difference of presented procedure in this research with previous research is that by using this procedure it is possible to correct the situation of all bridges by budget similar to previous cases. And reaching to relatively proper case, while in previous researches, by using multi-criterion decision making method, we only selected a bridge as a critical bridge that was in most critical case and all budget was spend first for this bridge and then was spend for other bridges. The results show that each of bridges in which parameters has debility. So, it is necessary to do all schemes for resisting these bridges against earthquake and to prevent from probable difficulties, caused by earthquake on these bridges. Finally the result show that steel legs buckling at the first bridge and the second is necessary for reform.