Improving the Seismic behavior of Repairable Systems with a Cradle Mechanism in Irregular Mass steel Braced Buildings in Plan

Subject Areas : Analysis of Structure and Earthquake

Mohsen Mohajer Tabrizi ¹ ( دانشجوی دکتری مهندسی زلزله، گروه مهندسی عمران، واحد تهران جنوب، دانشگاه آزاد اسلامی، تهران، ایران. )
Abbas Akbarpour ² ( faculty member of the Department Of Civil Engineering, South Tehran Branch , Islamic Azad University,Tehran, Iran )
Abdul Reza Saroqd Moghadam ³ ( عضو هیأت علمی تمام وقت، گروه مهندسی سازه، پژوهشگاه بین المللی زلزله شناسی و مهندسی زلزله )
Maryam F. Nezamabadi ⁴ ( Faculty member of Department Of Civil Engineering, At The Center For Modelling Of The South Tehran Branch Islamic Azad University,Tehran, Iran. )
Mohammadreza Adib Ramezani ⁵ ( Department of Civil Engineering, South Tehran Branch, Islamic Azad University, Tehran, Iran )

Received: 2022-12-05 Accepted : 2023-03-15 Published : 2023-04-17

Keywords: seismic behavior, repairable systems, cradle mechanism, steel buildings, mass irregularity in the plan,

Abstract :

This research has investigated the improvement of the seismic behavior of repairable systems with a cradle mechanism in steel braced buildings with irregular mass in plan. A new method is used to find a suitable method in a building with a regular plan with asymmetric mass distribution, in order to reduce the adverse effects of the structure and to quickly repair the damage caused to the structure after a strong earthquake. In this method, by creating lifting conditions at the base of braced bay columns and by using energy-dissipating devices in this part, energy absorption and consumption are transferred to this part of the structure and prevent damage to other parts. Based on the results, the effect of taking into account the effects of vertical and horizontal earthquakes in different mass irregularities of structures in the seismic performance of low-rise structures was determined. Also, the irregularities in the numerical model of the structure have a significant effect on the IDA curves. As the height of the structure increases in the four failure modes, the mean probability of fragility of the structures occurs at a lower Sa, which means that the vulnerability of the structure increases. Also, with the increase in height, the slope of Sa reduction in four failure modes becomes milder, and the fragility curves for two IO performance levels and CP performance level have been obtained for all 6 structures. Considering the effect of irregularities, they are significantly effective in the structural failure of structures, so that considering the effect of these irregularities in mass distribution can lead to an increase in the probability of structural failure.