The Mexico Earthquake of September 19, 1985—Case Studies of Seismic Strengthening for Two Buildings in Mexico City

1989 ◽  
Vol 5 (1) ◽  
pp. 153-174 ◽  
Author(s):  
D. A. Foutch ◽  
K. D. Hjelmstad ◽  
E. Del Valle Calderón ◽  
E. Figueroa Gutiérrez ◽  
R. E. Downs

The earthquake that shook Mexico City on 19 September 1985, destroyed several hundred buildings and took thousands of lives. Two buildings located in the most highly damaged part of the city experienced strong shaking, but suffered only slight damage. These reinforced concrete frame buildings had been retrofit with steel bracing systems and infill reinforced concrete walls prior to the earthquake. Forced vibration tests, analytical studies and geotechnical investigations for each building have been conducted. The results indicate that the steel bracing systems strengthened the buildings and stiffened them, moving their natural periods away from the 2.0-second predominant ground period in that part of the city. Implications for the design of strengthening systems have been determined.

2021 ◽  
Vol 26 (3) ◽  
pp. 28-43
Author(s):  
A. Bahrami ◽  
O. Nexén ◽  
J. Jonsson

Abstract The purpose of this research is to specify the differences between the performance of cross-laminated timber (CLT) and reinforced concrete (RC) walls. The study is done by using the finite element structural analysis and design software, StruSoft FEM-Design, in order to model, analyse and design a reference building located in the city of Gävle in Sweden. The building is firstly modelled, analysed and designed using RC walls and then the RC walls are replaced with CLT walls. In both buildings, other load-bearing elements such as slabs, beams and columns are made of RC while the roof beams are made of glulam. It is found that employing RC has advantages, especially regarding thickness. The results show that the CLT walls require larger dimensions than their RC counterparts. Meanwhile, it is demonstrated that the slabs, beams and columns made of RC in the building having the CLT walls require more reinforcement or larger thickness than the case of walls made of RC. Moreover, the total weight of the building having the CLT walls is 74% of the building having the RC walls. The lower weight of the building having the CLT walls has great advantages such as having lighter foundation and being cost-effective and also beneficial for the environment.


2000 ◽  
Vol 27 (3) ◽  
pp. 433-444 ◽  
Author(s):  
H Abou-Elfath ◽  
A Ghobarah

The seismic performance of low-rise nonductile reinforced concrete (RC) buildings rehabilitated using concentric steel bracing is investigated. A three-story building was analysed using various ground motion records. The effectiveness of the steel bracing in rehabilitating the three-story building was examined. The effect of the distribution of the steel bracing along the height of the RC frames on the seismic performance of the rehabilitated building was studied. The behaviour of the nonductile RC frame members is represented using a beam-column element capable of modelling the strength softening and the effects of the axial force on the yield moment and the deformation capacities at peak strength of these members. The performance of the building is evaluated in terms of global and story drifts and damage indices. A simplified approach is proposed for selecting the proper brace distribution.Key words: reinforced concrete, frame, nonductile, rehabilitation, concentric steel brace.


2019 ◽  
Vol 8 (3) ◽  
pp. 1029-1034

The design of the 15 storey R.C building (seismic zone V) is made in accordance with IS 456:2000 using ETABS software. It is already reported that provision of concentric bracing throughout the building are reliable during seismic activity. Hence, this work is aimed to improve the performance of multi storey R.C. building by provision of eccentric steel bracing through analysis. Different types of bracing such as V bracing, Chevron bracing and Diagonal bracing are provided in concentric and eccentric manner. The effect of distribution of steel bracing throughout the height of the building is examined. It is found that the deflection in the building increases with increase in eccentricity. Moreover, V type bracing with 10 percentage eccentricity is found to be most reliable under seismic activity compared to other arrangements.


2020 ◽  
Vol 12 (24) ◽  
pp. 10360
Author(s):  
Hyun-Do Yun ◽  
Sun-Woong Kim ◽  
Wan-Shin Park ◽  
Sun-Woo Kim

The purpose of this study was to experimentally evaluate the effect of a hinged steel damping system on the shear behavior of a nonductile reinforced concrete frame with an opening. For the experimental test, a total of three full-scale reinforced concrete frame specimens were planned, based on the “no retrofitting” (NR) specimens with non-seismic details. The main research questions were whether the hinged steel damping system is reinforced and whether torsion springs are installed in the hinged steel damping system. From the results of the experiment, the hinged steel damping system (DR specimen) was found to be effective in seismic retrofitting, while isolating the opening of the reinforced concrete (RC) frame, and the torsion spring installed at the hinged connection (DSR specimen) was evaluated to be effective in controlling the amount of deformation of the upper and lower dampers. The strength, stiffness, and energy dissipation capacity of the DSR specimen were slightly improved compared to the DR specimen, and it was confirmed that stress redistribution was induced by the rotational stiffness of the torsion spring installed in the hinge connection between the upper and lower frames.


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