چكيده به لاتين
Abstract:
Today , importance of bridges safety in urgent condition is increasing due development of transportion networks and widespread exploiting bridges. Previous earthquakes and extensive destruction of bridges obviously show insufficient regulations for moderate to strong earthquakes.
Bridges destruction has different reasons , and in this research we would consider different sources, comprehensively . Among these factors ,there is a case , in which all compound and elements of bridge remain safe and only deck would fall. Meanwhile,we consider those factors of deck falling like Neoprene slip, which cause slipping of the lateral movement .
In order to discuss effect of this phenomenon , this research study a concrete bridge across a river in 179KM away from Dorud-Khoramabbadrailway.As there is no suitable record about available faults around this bridge foreign records have been used. Seven acceleration mappings with different origins, mechanisms and intensities in each areas are used for analyzing the time history. SAP2000 software has been used to model the bridge.
In this study,according to AASHTOO 2014 regulations , variation in ratio of shifting of deck and changes in bases and backpacks and possibility of deck fall to minimum seat length , have been studied and compared for Iran and Taiwan.
Generally, comparison of the results between length shift in Neopern condition and in free movement condition have shown that in most cases shift would increase by decreasing in friction and in turn,confidence coefficient of deck fall would decrease in different regulation: and sometimes it has violated from its specified range.
In this research we considered changes in bridge shearbase and observed that although decline in friction would leads to increase in bridge length shift, but it would significantly decrease shearbase , which in turn is helpful for the whole structure.
