The Mexico Earthquake of September 19, 1985—Performance of Low-Rise Buildings in Mexico City

1989 ◽  
Vol 5 (1) ◽  
pp. 121-143 ◽  
Author(s):  
E. Miranda ◽  
V. V. Bertero
Keyword(s):  
Reinforced Concrete ◽  
Mexico City ◽  
Soft Soil ◽  
Time History ◽  
Federal District ◽  
Excellent Performance ◽  
Soil Zone ◽  
Space Frames ◽  
Dynamic Analyses ◽  
Mexico Earthquake

This paper summarizes the results of analytical studies conducted to understand the observed performance of low-rise buildings located in the soft-soil zone of Mexico City during the 1985 Michoacan earthquake. Two low-rise reinforced concrete moment resistant space frames were designed in accordance with the 1976 Code for the Federal District of Mexico. They were subjected to a series of static and time history dynamic analyses. The results indicate that the designed buildings have significantly larger lateral strengths than required by the Code and that these overstrengths were the main reason for the excellent performance of most of the low-rise buildings in Mexico City during the 1985 Michoacan earthquake.

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
Keyword(s):  
Reinforced Concrete ◽  
Mexico City ◽  
Reinforced Concrete Frame ◽  
Concrete Walls ◽  
Concrete Frame ◽  
Reinforced Concrete Walls ◽  
Steel Bracing ◽  
Geotechnical Investigations ◽  
Mexico Earthquake ◽  
The City

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.

The Mexico Earthquake of September 19, 1985—Statistics of Damage and of Retrofitting Techniques in Reinforced Concrete Buildings Affected by the 1985 Earthquake

1989 ◽  
Vol 5 (1) ◽  
pp. 145-151 ◽  
Author(s):  
J. Aguilar ◽  
H. Juárez ◽  
R. Ortega ◽  
J. Iglesias
Keyword(s):  
Reinforced Concrete ◽  
Statistical Analysis ◽  
Data Base ◽  
Mexico City ◽  
Failure Modes ◽  
Reinforced Concrete Buildings ◽  
Concrete Buildings ◽  
Mexico Earthquake

The 1985 Mexico City earthquake caused very serious damage, especially in reinforced concrete buildings, making it necessary to repair and strengthen many structures. The authors had the opportunity to study 114 of these retrofitted buildings. The data base created with the collected information contains the description of the building, its damages and the retrofitting techniques used. The statistical analysis of this information makes it possible to identify the correlation among the structural and foundation types, the dominant failure modes, the causes of damage and the repair and strengthening techniques used in this group of buildings.

Inelastic Dynamic Seismic Response of 15-Story and 25-Story RC Buildings with and without Shear Walls Designed with the Mexico City Building Code

2015 ◽  
Vol 665 ◽  
pp. 81-84
Author(s):  
Jorge A. Avila ◽  
Jorge Arturo Avila-Haro
Keyword(s):  
Mexico City ◽  
Soft Soil ◽  
Shear Walls ◽  
Building Code ◽  
Limit States ◽  
Foundation Design ◽  
Seismic Demands ◽  
Soil Zone ◽  
Group B ◽  
A Minor

The inelastic seismic behavior of two reinforced concrete buildings of 15-story and 25-story is compared with and without shear-walls. The resistance-seismic design and vertical loads is made according to the requirements of the Mexico City Building Code, RCDF-2004, satisfying the limit states of service and resistance: compressible seismic area, group B. Inelastic dynamic seismic responses are determined with step-by-step analysis under SCT-EW-85 record with the nominal resistance and over-resistance effects. Results show the importance of the participation of the shear-walls to help to reduction of the magnitude of structural damages during severe seismic future events. The shear walls located in adequate form inside the structure provide an excellent additional lateral stiffness to solve the common flexibility problems in the soft soil zone of the Valley of Mexico and therefore to avoid severe additional torsion problems. In the shear wall constructions we should pay special attention to the foundation design. It was verified that the shear strengths of the structural elements selected were higher than the seismic demands. In the cases of over-strengths considered, it can be concluded that had a minor incursion in the interval of inelastic performance compared with the inelastic performance presented in the cases of nominal strengths.

The Mexico Earthquake of September 19, 1985—The Seismic Performance of Buildings with Weak First Storey

1989 ◽  
Vol 5 (1) ◽  
pp. 89-102 ◽  
Author(s):  
S. E. Ruiz ◽  
R. Diederich
Keyword(s):  
Mexico City ◽  
Soft Soil ◽  
Absorption Capacity ◽  
Ductility Demand ◽  
Displacement Ductility ◽  
Lateral Resistance ◽  
Lateral Strength ◽  
Mexico Earthquake ◽  
Range Of Values ◽  
Acceleration Record

During the Michoacan earthquake of Séptember 19, 1985, 8 percent of the damaged buildings in the Mexico City area were characterized by a first storey much weaker than the upper ones. Although it is recognized that these failures may have resulted from the combination of several features, in this paper it is intended to study the possible influence of the lateral strength discontinuity in the ductility demand at the first storey, and to try to understand the behaviour of this type of structures under the actions of the East-West component of the highest acceleration record obtained on soft soil in Mexico City during the mentioned earthquake. A parametric study for five and twelve-storey buildings with weak first storey is presented in this paper. The infill walls in the upper storeys were brittle in some cases and ductile in others. For certain cases, the results show the existence of a range of values of the ratio of seismic lateral resistance of the upper storeys to that of the lowest one for which ductility demands at the lowest story can be considerably higher than for other intervals. It is shown that the absorption capacity of ductile walls plays an important role in the displacement ductility demands of the first storey.

Seismic Response Analysis of a Retrofitted Concrete Building in Mexico City

2019 ◽  
Author(s):  
Ulises Ruiz Barba ◽  
Juan Murcia-Delso ◽  
Oriol Arnau ◽  
David Muria-Vila ◽  
Sergio M. Alcocer
Keyword(s):  
Reinforced Concrete ◽  
Mexico City ◽  
Analytical Model ◽  
Soft Soil ◽  
Ambient Vibration ◽  
Response Analysis ◽  
Vibration Properties ◽  
Moderate Earthquake ◽  
Ambient Vibration Testing ◽  
Concrete Building

<p>This paper presents results of an ongoing study on the seismic performance of a retrofitted concrete building located in the soft soil area of Mexico City. The original structure consisted of reinforced concrete frames in two directions. The building was repaired and retrofitted after having been damaged during a moderate earthquake in 1979. The retrofit strategy consisted mainly of installing external steel braces in one direction of the building, and reinforced concrete infill walls in the other direction. The retrofitted structure showed minor damage after the 1985 and 2017 earthquakes. The goal of this investigation is to assess the structural response of the building and the effectiveness of the retrofit strategy by combining post-earthquake damage inspections, analytical modeling and ambient vibration testing. This paper focuses on the development and calibration of a three-dimensional analytical model of the building, and on the analysis of the vibration properties of the retrofitted structure. The analytical model has been calibrated using data from ambient vibration tests conducted after the 2017 event. The study of the vibration properties of the building has shown the strong influence of soil-structure interaction in the response of this building.</p>

Observations of Rayleigh waves in Mexico City Valley during the 19 September 2017 Puebla–Morelos, Mexico earthquake

2020 ◽  
Vol 36 (2_suppl) ◽  
pp. 62-82
Author(s):  
Pablo Heresi ◽  
Jorge Ruiz-García ◽  
Omar Payán-Serrano ◽  
Eduardo Miranda
Keyword(s):  
Surface Waves ◽  
Mexico City ◽  
Edge Effects ◽  
Rayleigh Waves ◽  
Soft Soil ◽  
Inner Product ◽  
Basin Edge ◽  
Literature Evidence ◽  
Mexico Earthquake ◽  
Stockwell Transform

This article discusses the principal features of Rayleigh surface waves generated by basin-edge effects in Mexico City during the Mw7.1 19 September 2017 Puebla–Morelos, Mexico earthquake. Rayleigh waves were extracted from ground motions recorded at 12 stations in Mexico City. We used a recently proposed method for extracting surface waves, where the earthquake record is filtered based on the normalized inner product of the Stockwell transform of the three-component earthquake recordings. Results of this study reveal that basin-edge effects produced strong Rayleigh waves, particularly at certain stations, with frequencies that are mainly between 0.2 and 0.9 Hz, which is consistent with previous frequency ranges reported in the literature. Evidence of higher-mode Rayleigh waves was found at all stations located on soft soil sites, even at stations that are more than 1 km away from the basin edges. It was also observed that peak acceleration spectral ordinates of the retrograde component of the extracted Rayleigh waves at two stations exceeded the design spectral ordinates of the 1976 and 2004 editions of the Mexico City Seismic Provisions.

The Mexico Earthquake of September 19, 1985—Behavior of Building Foundations in Mexico City

1988 ◽  
Vol 4 (4) ◽  
pp. 835-853 ◽  
Author(s):  
M. J. Mendoza ◽  
G. Auvinet
Keyword(s):  
Mexico City ◽  
Soft Soil ◽  
Shear Forces ◽  
Natural Period ◽  
Plastic Deformations ◽  
Long Period ◽  
Cyclic Stresses ◽  
Static Contact ◽  
Mexico Earthquake ◽  
Main Factor

During the 1985 earthquake, a number of building foundations in the lacustrine soft soil area of Mexico City presented an inadequate performance. Previous high static contact stresses between the foundation and the supporting subsoil propitiated the appearance of plastic deformations of the soil under seismic cyclic stresses, which led to settlements and tilting of the buildings. Foundations of all kinds showed different degrees of vulnerability to the earthquake, but constructions on friction piles sustained the most severe damages. This can be attributed in some cases to non compliance with the accepted design criteria and current regulations. The main factor was however the pronounced dynamic magnification of seismic movements associated to the quasi coincidence between the natural period of some structures with moderate height on friction piles, and the long period of the subsoil motions, which led to large overturning moments and shear forces at the foundation level.

The Mexico Earthquake of September 19, 1985—Nonstationary Models of Seismic Ground Acceleration

1988 ◽  
Vol 4 (3) ◽  
pp. 551-568 ◽  
Author(s):  
M. Grigoriu ◽  
S. E. Ruiz ◽  
E. Rosenblueth
Keyword(s):  
Mexico City ◽  
Stationary Process ◽  
Soft Soil ◽  
Nonstationary Process ◽  
Oscillatory Process ◽  
Ground Acceleration ◽  
Single Degree Of Freedom ◽  
Single Degree ◽  
Coefficients Of Variation ◽  
Mexico Earthquake

Characteristics of a nonstationary process obtained by modulating the amplitude and frequency of a stationary process differ from those of an oscillatory process. An accelerogram recorded in the soft soil of Mexico City during the 1985 earthquake serves to calibrate both nonstationary models. Responses of linear and nonlinear single-degree-of-freedom systems indicate that the process with modulated amplitude and frequency is preferable for reliability studies. Coefficients of variation of ductility demands of systems excited with accelerograms generated by the model with modulated amplitude and frequency are close to those corresponding to actual accelerograms.

The Mexico Earthquake of September 19, 1985—Seismic Zoning of Mexico City after the 1985 Earthquake

1989 ◽  
Vol 5 (1) ◽  
pp. 257-271 ◽  
Author(s):  
J. Iglesias
Keyword(s):  
Mexico City ◽  
Soft Soil ◽  
Resistance Coefficient ◽  
Seismic Zoning ◽  
Base Shear ◽  
Severe Damage ◽  
Seismic Capacity ◽  
Mexico Earthquake ◽  
The City ◽  
Resistance Coefficients

Using a simplified method for the evaluation of the seismic capacity of medium rise concrete structures, it was possible to obtain the base shear coefficient corresponding to failure (resistance coefficient) for 162 buildings, and use it as an evaluation index. The resistance coefficients of the 90 evaluated structures that suffered severe damage were used to elaborate a map of intensities for the 1985 Mexico City earthquake. This map shows the strong interaction of neighboring zones of firm soil or rock that amplify the ground motion in the soft soil between them as much as 100%, this being the main reason for the high intensities observed in some districts of the city. Based on these results, a new seismic zoning was proposed for the chapter of the 1987 Mexico City Building Code.

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