Seismic Performance Evaluation of Existing Bridges According to the Recent Requirements of AASHTO Using Nonlinear Static Analysis (Case Study of Al Khreibat Bridge on Lattakia -Tartous Road)

تم في هذا البحث تقييم الأداء الزلزالي لأحد الجسور القائمة و الذي يمثل نموذجاً لمجموعة كبيرة من الجسور المحلية متعددة الفتحات ذات الاستناد البسيط و ذلك من خلال وضع نموذج فراغي للجسر باستخدام برنامج SAP2000V19.1 و إجراء التحليل الستاتيكي اللاخطي. تمت الاستفادة من نتائج هذا التحليل في التحقق من إيفاء الجسر بمتطلبات AASHTO للتصميم الزلزالي و التي تتضمن التحقق من كل من متطلب استطاعة P-Δ, و طلب/ استطاعة الانتقال, و مطاوعة العناصر (الأعمدة), و كذلك التحقق من طلب/استطاعة القص للأعمدة. بينت النتائج أن أداء الجسر المدروس بحالته الراهنة و من أجل الشدات الزلزالية المعتمدة في الكود السوري يحقق المستوى المطلوب و هو الحفاظ على الحياة (LS), و لكنه يتجاوز هذا المستوى من أجل شدة زلزالية عالية, كما بين البحث التوافق بين نتائج التحليل الستاتيكي اللاخطي و متطلبات AASHTO

Bridges are important and vital structures that provide communication between different regions. Due to their importance, their design has had a great attention throughout the world, as evidenced by the continuous development of seismic design codes such as AASHTO, which now adopts the performance-based design, and requires through a set of requirements and criteria that the bridge performance under the design earthquake is at life safety (LS) level and thus ensures that it does not collapse. Since most of the local bridges were built at periods where these criteria were not adopted, it is important to verify their performance and that they meet these criteria. In this paper, the seismic performance of an existing bridge, which represents a model for a wide range of local multi-span simply supported bridges, was evaluated by developing a 3D model of the bridge using SAP2000V19.1 and applying the nonlinear static analysis. The results of analysis have been used to verify that the bridge meets the AASHTO seismic requirements, which include the check of the P-Δ requirement, displacement demand/ capacity, members (columns) ductility, as well as the check of the shear demand/capacity of the columns. The results showed that the performance of the studied bridge under the seismic intensities adopted in the Syrian code achives the acceptable level which is life safity (LS), but it exceeds this level under high seismic intensity. The research also showed that there is compatibility between the results of nonlinear static analysis and AASHTO requirements.