رضا بذرگری - گروه مهندسی عمران و محیط زیست، دانشگاه هیوستون، ایالات متحده آمریکا
آرین سیلانی - دانشکده مهندسی عمران، دانشگاه علم و صنعت ایران، تهران، ایران.
سعیده ضیا دیدگان - گروه مهندسی عمران، دانشگاه صنعتی شریف،تهران، ایران
سید آرین شجاعی - گروه مهندسی عمران، دانشگاه صنعتی شریف، تهران، ایران.

Today, controlling of structures’ progressive collapse decreases damages while natural and unnatural events happen. This issue requires deliberation and consideration for cable-stayed bridges which their utilization in the country is going to increase, so by taking previous surveys into consideration, the best design for the cable-stayed bridge is gained. In this study, the structure’s progressive collapse is investigated by alternative load path method. In this method there is an effort to make certitude about the appropriate joint between vertical and horizontal components, in a way that the structure has the ability of load transfer with the elimination of any components of the structure. In order to control this phenomenon in the potential state, destruction of the bridge’s elements is evaluated by linear and non-linear static and dynamic processes. In this survey, first the mentioned cable-stayed bridge with assumed geometrical characteristics and materials is designed two-dimensional by relevant regulations. This study and design is performed by SAP۲۰۰۰ computer program and then the designed system’s response to the progressive collapse is controlled by static and dynamic methods. But the ultimate purpose of this research is to study geometrical changes of the design such as changes in horizontal distances of cables and changes in pylon altitude or altitude-to-span ratio and the effects of these factors in the mentioned progressive collapse and to compare them. By investigating this research models under dead load, we came to the conclusion that when two cables of the structure are destroyed as a result of breaking away, force redistribution occurs and forces in all the cables are increased. This increase can be up to ۱.۵ times more and causes forces to exceed the limit which the cables are designed for and therefore it causes destruction of the cable and the structure. But in general the structure is less likely to proceed to the progressive collapse as a result of gravity loads.   ***All authors have contributed equally to this work.

Progressive collapse, Cable-Stayed Bridge, gravity loads, destruction