Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 52 10 2020 12 21 Evaluation of Reduction Factor for concrete coatings of underground structures under blast loading Evaluation of Reduction Factor for concrete coatings of underground structures under blast loading 2515 2528 3625 10.22060/ceej.2019.14735.5733 FA Safa Peyman School of Civil Engineering, Imam Hossein University, Tehran, Iran Mohammad Hossein Taghavi Parsa IHU,QOM ac 0000-0002-2968-7294 Amin Babaie دانشگاه امام حسین علیه السلام Ahmad Akbari sahel Consulting Journal Article 2018 07 25 The reduction factor (R) is one of the most important parameter of loading, analyzing and designing structures subjected to dynamic loading such as earthquake and explosion. This coefficient considers the nonlinear behavior of the structure in linear analysis. Investigations show that the acceptable range for reduction factor of concrete coating of underground structures applied to explosive loading is not determined completely. To find out this factor, the tunnel structure must first be modeled numerically. The interaction between the structure and the soil and their mechanical properties should be modeled so Winkler spring was proposed. In this research, plastic hinges were introduced in the SAP2000 software, and a pushover analysis was carried out. Outputs of this analysis result in the vertical force-displacement diagrams and their behaviors were plotted for each tunnel performance levels. The Reduction Factor is obtained for a special pattern loading of explosive charge by using the relationships which is developed in this research. It can be noted that the reduction factor for such structures depends on two parameters including ductility and strength factor The reduction factor (R) is one of the most important parameter of loading, analyzing and designing structures subjected to dynamic loading such as earthquake and explosion. This coefficient considers the nonlinear behavior of the structure in linear analysis. Investigations show that the acceptable range for reduction factor of concrete coating of underground structures applied to explosive loading is not determined completely. To find out this factor, the tunnel structure must first be modeled numerically. The interaction between the structure and the soil and their mechanical properties should be modeled so Winkler spring was proposed. In this research, plastic hinges were introduced in the SAP2000 software, and a pushover analysis was carried out. Outputs of this analysis result in the vertical force-displacement diagrams and their behaviors were plotted for each tunnel performance levels. The Reduction Factor is obtained for a special pattern loading of explosive charge by using the relationships which is developed in this research. It can be noted that the reduction factor for such structures depends on two parameters including ductility and strength factor https://ceej.aut.ac.ir/article_3625_dd7970532bfa1449085b8f43fc39a7d5.pdf