Eccentric Steel Bracing for Seismic Retrofitting of Non-Ductile Reinforced Concrete Frames

Author(s):  
M. Valente
Author(s):  
Silpa S ◽  
Chinsu Mereena Joy

One of the major causes of the collapse of buildings are earthquakes. Reinforced concrete structures are vulnerable to seismic activities and can destruct the structures. The RC structures which are prone to seismic activities should be protected and need to be retrofitted to resist the seismic loads. Retrofitting is one of the best methods which can be used to strengthen the structures safe against seismic loads. Retrofitting techniques will increase the strength, stiffness, ductility and stability of structures as well as reduce the operation costs and environmental impacts. Various techniques of retrofitting can be adapted to improve the stability of the structure. One of the most effective method for retrofitting of structures is the use of steel bracings. Steel bracing can be effectively used for enhancing the earthquake resistance of seismically inadequate reinforced concrete frames. This paper reviews the effect of different steel bracing patterns used as retrofitting technique in the seismic performance of the structures.


2019 ◽  
Vol 8 (1) ◽  
pp. 89-101
Author(s):  
Naima Ezzaki ◽  
Daniel Stoica ◽  
Laurentiu Rece ◽  
Arina Modrea

Abstract This article aims to highlight, through a comparative study, the efficiency of steel bracing systems used to reduce seismic vulnerabilities in existing buildings with reinforced concrete structures (reinforced concrete frames and reinforced concrete dual structures, general building structures including those used in transport infrastructure). In order to simplify the calculations, the analysis was reduced to the study of the behavior of resistance lines corresponding to four-, nine- and fifteen-level buildings with the same plane distribution. In order to obtain features similar to those of existing building elements, structures were initially loaded with seismic forces corresponding to code P13-63. The next step was to apply to previously dimensioned structures the seismic loads according to P100-3: 2008 in relation to P100-1: 2013, thus obtaining the deficiencies of the existing structures against the requirements of these norms. Correction of these strength and stiffness deficiencies was attempted by introducing X-shaped centric brace systems. The bracing systems used as consolidation methods are of three types: direct bracings stuck in the reinforced concrete frames and bracings of the indirect type, made of internal and external bracing steel frames. Structural calculations were made in the linear elastic field using the ETABS program.


2020 ◽  
Vol 87 (1) ◽  
pp. 92-100 ◽  
Author(s):  
N.V. FEDOROVA ◽  
◽  
FAN DINH GUOK ◽  
NGUYEN THI CHANG ◽  
◽  
...  

Author(s):  
Seung-Jae Lee ◽  
Tae-Sung Eom ◽  
Eunjong Yu

AbstractThis study analytically investigated the behavior of reinforced concrete frames with masonry infills. For the analysis, VecTor2, a nonlinear finite element analysis program that implements the Modified Compression Field Theory and Disturbed Stress Field Model, was used. To account for the slip behavior at the mortar joints in the masonry element, the hyperbolic Mohr–Coulomb yield criterion, defined as a function of cohesion and friction angle, was used. The analysis results showed that the lateral resistance and failure mode of the infilled frames were significantly affected by the thickness of the masonry infill, cohesion on the mortar joint–brick interface, and poor mortar filling (or gap) on the masonry boundary under the beam. Diagonal strut actions developed along two or three load paths on the mortar infill, including the backstay actions near the tension column and push-down actions near the compression columns. Such backstay and push-down actions increased the axial and shear forces of columns, and ultimately affect the strength, ductility, and failure mode of the infilled frames.


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