Irregular Ground Analysis to Interpret Time-Characteristics of Strong Motion Recorded in Mexico City during 1985 Mexico Earthquake

1987 ◽  
pp. 467-476 ◽  
Author(s):  
H. Kawase
Keyword(s):  
Mexico City ◽  
Strong Motion ◽  
Mexico Earthquake

The Culprit in Mexico City—Amplification of Motions

1987 ◽  
Vol 3 (2) ◽  
pp. 315-328 ◽  
Author(s):  
M. Celebi ◽  
J. Prince ◽  
C. Dietel ◽  
M. Onate ◽  
G. Chavez
Keyword(s):  
Mexico City ◽  
Strong Motion ◽  
Spectral Ratios ◽  
Long Distance ◽  
Resonant Frequencies ◽  
Low Frequencies ◽  
Mexican Pacific ◽  
Motion Data ◽  
Subsurface Environment ◽  
Mexico Earthquake

Mexico City has repeatedly suffered from the long-distance effects of the earthquakes that originate as far away as the subduction trenches near the Mexican Pacific Coast. The Michoacan, Mexico earthquake of 19 September 1985 was no exception and caused extensive damage to property and numerous loss of lives. The unique subsurface condition resulting from the historical lakebed has distinct resonant low frequencies around 0.5 Hz. The strong earthquake motions from long distances as well as the locally originating weak motions cause large amplifications at resonant low frequencies in the subsurface environment of Mexico City lakebed. In this paper, the resonant frequencies and associated amplification of motions in Mexico City are quantified in terms of spectral ratios using 19 September 1985 strong-motion data and weak motions recorded in January, 1986. These ratios confirm that the amplification of motions at resonant frequencies due to the subsurface conditions is indeed the culprit.

The Mexico Earthquake of September 19, 1985—Ductility and Resistance Requirements Imposed on a Concrete Building

1989 ◽  
Vol 5 (1) ◽  
pp. 41-50 ◽  
Author(s):  
E. Sordo ◽  
A. Terán ◽  
J. J. Guerrero ◽  
H. Juárez ◽  
J. Iglesias
Keyword(s):  
Dynamic Analysis ◽  
Mexico City ◽  
Spectral Response ◽  
The Real ◽  
Linear Dynamic ◽  
Ductility Factor ◽  
Concrete Building ◽  
Waffle Slab ◽  
Mexico Earthquake ◽  
Peak Value

This paper describes the study of a twelve floor concrete building with a waffle slab system located 300 meters from the accelerometer at Secretaria de Comunicaciones y Transportes (S.C.T) in Mexico City. First, the reduced seismic coefficient associated with the failure of the critical story is calculated by a linear dynamic analysis which reproduces the damage provoked by the 1985 earthquake to the real structure. Second, the ductility factor associated with the damaged stories is obtained through a step-by-step non-linear dynamic analysis. Finally, the peak value of the S.C.T. maximum ordinate for spectral response corresponding to 5 percent of critical damping was determined from this analysis.

The Mexico Earthquake of September 19, 1985—New Accelerograph Network for Mexico City

1989 ◽  
Vol 5 (1) ◽  
pp. 249-255 ◽  
Author(s):  
J. M. Espinosa-Aranda ◽  
A. Uribe ◽  
B. Frontana ◽  
O. Contreras ◽  
G. Ibarrola
Keyword(s):  
Local Government ◽  
Mexico City ◽  
Seismic Records ◽  
Mexico Earthquake ◽  
Field Stations

As a result of the observed effects induced by the earthquakes of September 1985 in Mexico City's structures, the local government authorities increased their support for the installation of accelerographs in a network covering different zones of Mexico City. This paper presents the activities developed by the Centro de Instrumentación y Registro Sísmico (CIRES) concerned with: selection and procurement of suitable instruments, identification of the installation sites, and the installation of field stations. We also describe methods applied to the processing of seismic records and include a summarized catalog of accelerograms recorded to date.

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.

The Mexico Earthquake of September 19, 1985—Typical Cases of Repair and Strengthening of Concrete Buildings

1989 ◽  
Vol 5 (1) ◽  
pp. 175-193 ◽  
Author(s):  
M. Jara ◽  
C. Hernández ◽  
R. García ◽  
F. Robles
Keyword(s):  
Case Studies ◽  
Mexico City ◽  
Damage Assessment ◽  
Analysis And Design ◽  
Concrete Buildings ◽  
Temporary Protection ◽  
Practical Design ◽  
Mexico Earthquake ◽  
Emergency Measures ◽  
Made In

It is the aim of this paper to describe the most important techniques that are being used in Mexico City to retrofit buildings damaged during the 1985 earthquake. The information is presented by means of four case studies. These cases offer practical design examples of the typical solutions adopted and illustrate the various aspects of the repair and strengthening process such as damage assessment, emergency measures for temporary protection, the retrofitting technique employed in each case and considerations and decisions made in the analysis and design.

The Mexico Earthquake of September 19, 1985—Past Decisions, Present Danger: An Historical Perspective on Ecology and Earthquakes in Mexico City

1988 ◽  
Vol 4 (3) ◽  
pp. 469-479 ◽  
Author(s):  
S. Tobriner
Keyword(s):  
Mexico City ◽  
Historical Perspective ◽  
The World ◽  
History Of ◽  
Mexico Earthquake

Why is one of the most populous cities in the world built on land which has a history of subsidence, seismicity, and flooding? Mexico City illustrates how early decisions in a city's history can create difficult conditions for building well and living safely. The Aztecs had little choice but to live on the muddy islands in Lake Texcoco which now lie beneath downtown Mexico City. But the Spanish did have a choice. By selecting the island capital of Tenochtitlan for their colonial capital they bequeathed to succeeding generations problems which were apparent to them almost immediately after they began construction. Their solution to the hydraulic problems of the site only exacerbated ecological and seismic problems which the inhabitants of Mexico City face today, and destroyed the reason the first settlers inhabited the Valley of Mexico.

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.

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