دانلود رایگان مقاله انگلیسی مقاوم سازی لرزه ای توزیع ستون RC برای ساختمان مدرسه موجود - الزویر 2018

ABSTRACT

Seismic retrofit technology has been significantly developed to reduce building damage during earthquakes. However, earthquakes are unpredictable natural disasters that should be dealt with flexibly. Hence, the seismic retrofitting method should be independently studied. In this study, the minimum number and the location of seismic retrofitted reinforced concrete columns required for school buildings in service are derived through an optimization technique. A time-history dynamic analysis of the frame structure comprising columns and beams is conducted using a three-dimensional finite element model to obtain empirical results. The study subject is a school building, which is a three-story RC structure with non-seismic details consisting of 62 RC columns on each floor (i.e., a total of 186 columns). The optimization analysis showed that retrofitting only 60.2% of the columns could withstand a peak ground acceleration of 0.2 g applied at the shear critical regions at both column ends.

5. Conclusions

This study derived the optimal number and the location of retrofitted RC columns by linking the optimization technique with a 3D non-linear time-history analysis. Various results were obtained by performing the 3D non-linear dynamic analysis. Moreover, reliable optimization results were acquired using the ACO optimization technique. The main contributions of the study are as follows:

(1) An algorithm that combines the ACO technique and the 3D nonlinear time-history analysis is proposed.

(2) The optimization using the ACO technique shows that reliable results could be derived.

(3) The structure strength varies according to the forcing direction of the earthquake. Its deviation is also large. The strength along the strong axis (Y-axis) is high because of the large number of spans. The strength significantly varies according to the forcing direction in school buildings with asymmetric loads and structures. Hence, the forcing direction must be closely examined, and the risk for the weak axis (X-axis) with fewer spans must be recognized.

(4) The seismic material proposed in this study must be installed in over 50% of the total columns for non-seismic school buildings to meet the current seismic design criteria.

(5) Further retrofitting is required for a higher PGA, which determines the strength of the seismic waves, for the weak axis (X-axis) with fewer spans and for lower floor levels. Retrofitting the outer columns is more effective than retrofitting the inner columns.

(6) A staggered positioning of the retrofitted columns over a wide area is more effective than continuous positioning. Applying different retrofitting locations to each floor contributes to economic benefits.