Abstract—In order to study the efficacy of several seismic retrofitting techniques on the seismic performance of existing multistory reinforced concrete structures, finite element analysis is conducted using the finite element package, SeismoStruct. First, three models are considered; 4-story, 8-story and 12-story reinforced concrete framed structures designed according to Saudi Building Code (2007) for vertical loads and seismic forces for 0.2-second and 1.0-second response spectral accelerations of 0.21g and 0.061g, respectively. Two conventional retrofitting techniques are considered to upgrade the structures to withstand seismic forces for 0.2-second and 1.0-second response spectral accelerations of 0.66g and 0.23g, respectively. These techniques are increasing the dimension of structural elements and attaching concentric steel braces at the middle bay of each story to the existing reinforced concrete frames. One more innovative retrofitting technique relying on adding passive control devices is considered in the analysis. Incremental dynamic analysis using records of twelve artificial and historic earthquakes is carried out. Fragility curves are developed for all original and retrofitted cases considering five different performance levels for the sake of the assessment of the effectiveness of different retrofitting techniques. Based on the results obtained, retrofitting existing reinforced concrete framed structures by adding concentric steel braces are the best technique that enhances their seismic performance, compared to other techniques.
 

Index Terms—retrofitting, incremental dynamic analysis, reinforced concrete frames, steel braces, fragility curves

Cite: Yasser E. Ibrahim Mansour, "Assessment of Seismic Retrofitting Techniques of RC Structures Using Fragility Curves," International Journal of Structural and Civil Engineering Research, Vol. 5, No. 3, pp. 175-182, August 2016. doi: 10.18178/ijscer.5.3.175-182