Strengthening of reinforced concrete frames by using steel bracings

Ağar, Mehmet
Structures in high seismic risk areas may be susceptible to severe damage in a major earthquake. Structures designed to meet older code requirements may be at even greater risk. When these structures are evaluated with respect to current code criteria, it is observed that they lack of lateral strength and/or ductility. Since safety and economic considerations are major problems, these structures become viable candidates for retrofit and seismic strengthening. For the variety of structures and possible deficiencies that arise, several retrofitting techniques can be considered. Diagonal bracing system is one of the retrofitting techniques and it provides an excellent approach for strengthening and stiffening existing building for lateral forces. Also, another potential advantage of this system is the comparatively small increase in mass associated with the retrofitting scheme since this is a great problem for several retrofitting techniques. In this study, the use of steel bracing for the strengthening of low, intermediate, and relatively high rise reinforced concrete frames are investigated analytically. The ultimate lateral load capacities of the strengthened frames are determined by a load controlled push-over analysis. The post-tensioning effect of preloading is also investigated.


Energy based seismic performance assessment of reinforced concrete columns
Acun, Bora; Sucuoğlu, Haluk; Department of Civil Engineering (2010)
Severe seismic events in urban regions during the last two decades revealed that the structures constructed before the development of modern seismic codes are the most vulnerable to earthquakes. Sub-standard reinforced concrete buildings constitute an important part of this highly vulnerable urban building stock. There is urgent need for the development and improvement of methods for seismic performance assessment of existing reinforced concrete structures. As an alternative to current conventional force-ba...
Nonlinear analysis of RC frames retrofitted with structural steel elements
Akpınar, Uğur; Binici, Barış; Department of Civil Engineering (2010)
Deficient concrete structures are serious danger in seismic zones. In order to minimize economical and human loss, these structures should be retrofitted. Selecting suitable retrofitting schemes requires detailed investigation of these systems. Considering these facts, this study aims to calibrate analytical models of systems with chevron braces and internal steel frames; and evaluate their seismic performances. First, analytical models of the frames with braces and internal steel frames were prepared and t...
Seismic vulnerability, behavior and design of tunnel form building structures
Balkaya, C; Kalkan, E (Elsevier BV, 2004-12-01)
Multi-story reinforced concrete tunnel form buildings are one of the common structural types in regions prone to high seismic risk due to the buildings inherent earthquake resistance and ease of construction. Despite their good performance during earthquakes in 1999 in Turkey, and abundance of such structures scattered worldwide, current seismic codes and design provisions provide insufficient guidelines for their seismic design. As a compensatory measure, a series of modal and nonlinear static analyses are...
Strengthening of reinforced concrete frames by custom shaped high strength concrete masonry blocks
Arslan, Güray; Polat, Mustafa Uğur; Department of Civil Engineering (2009)
Located on one of the highly active seismic fault systems in the world, the building stock in Turkey is mainly composed of reinforced concrete frames with 4-5 stories. Due to design and construction deficiencies resulting from the use of unqualified personnel and insufficient supervision, many of these buildings lack lateral stiffness, ductility and strength. For many structures, there is a need to alleviate these deficiencies by means of some rehabilitation techniques prior to earthquakes. One approach als...
Re-examination of damage distribution in Adapazari: Geotechnical considerations
Bakır, Bahadır Sadık; Yakut, Ahmet (Elsevier BV, 2005-06-01)
The role of ground conditions in damage distribution patterns of buildings in the city of Adapazari during the 17 August 1999 Izmit (Kocaeli) earthquake (M-w 7.4) is investigated. Damage was concentrated in the central districts of the city over the alluvial basin where four to seven-story reinforced concrete buildings were most adversely affected. Two distinct and mutually exclusive modes of building damage were observed on the alluvium: structural system failures due to strong ground shaking, and foundati...
Citation Formats
M. Ağar, “Strengthening of reinforced concrete frames by using steel bracings,” M.S. - Master of Science, Middle East Technical University, 2008.