Seismic eva‎luation of Bridges by using Multiple Tuned Mass Damper with Endurance Time Method

3/14/2024 12:00:00 AM

Bridges are considered as the most key members of the transportation network and they play a very important role in providing services before and after the occurrence of hazards such as earthquakes, which in case of their failure can cause huge human and financial losses to the communities. In order to prevent severe damage to bridges, the most cost-effective way is to retrofit bridges with weak performance. For this purpose, the use of control systems is considered a suitable method for the depreciation of earthquake energy in the bridge. Considering the wide range of features and characteristics of control systems, in this research, a single-column concrete bridge with 2 spans with a total length of 64 meters has been equipped with multiple Tuned mass dampers to improve its seismic performance. Due to the increasing complexities of structures, the use of analysis methods to estimate the performance of structures with appropriate accuracy and speed is one of the very important issues of structural strengthening. In this research, the Endurance Time method has been used as a dynamic method based on time history analysis, with the difference that the desired structure is subjected to increasing acceleration functions and its performance will be eva‎luated under different failure indicators. For this purpose, after determining the optimal parameters for multiple Tuned mass dampers, the mentioned bridge was modeled in Opensees software and its performance was based on the deck displacement parameter in the states before and after adding the damper to it using the time history analysis method and Endurance Time analysis was performed. Using the time history method, the maximum displacement of the deck after retrofitting with multiple Tuned mass dampers in parallel mode has decreased by 21%, and also the Endurance Time method has a good estimate of it with a small difference of 3%. In another part of this research, to ensure the accuracy and correctness of the obtained results, a comparison has been made between the results of the Endurance Time method and the time history analysis method using seven natural accelerometers suitable for type D soil. In this part, the mentioned accelerometers have been scaled to the range of FHWA regulations for an earthquake with a high level of Upper Level risk. Finally, it is possible to point out the appropriate accuracy of the Endurance Time method in determining the responses of the structure with a small difference compared to the time history analysis and consider it as an alternative method for the seismic eva‎luation of the structure. Finally, the performance of the bridge improved after retrofitting, so that its endurance increased from 16 to 24 seconds at the level of high damage.

روش زمان دوام , ميراگر جرمي تنظيم شده چندگانه , تحليل تاريخچه زماني , عملكرد لرزه اي

Endurance Time Method , Multiple Tuned Mass Damper , Time History Analysis , Seismic Performance

Mohammad Amin Zare

Dr. Mohsenali Shayanfar