The Mexico Earthquake of September 19, 1985—Live Load Specifications of the 1976 and 1987 Mexico City Building Codes

This work evaluates the damage to and collapse of a set of buildings in the September 2017 earthquake in Mexico City; these buildings were also subjected to the September 1985 Mexico City earthquake. These buildings were located in the area of the highest rate of damage or collapse in 1985, but buildings exhibiting significant damage or collapse in 2017 did not possess any retrofitting. The spectral demands for these buildings, based on typical records registered in the earthquakes of 1985 and 2017, were not much different, suggesting the need to explain why the buildings that collapsed suffered severe damage in 2017 but not in 1985. This building behavior was analyzed using a seismic damage index Id, previously proposed by the author, which considers the effect of cumulative damage. The results indicated that the observed damage to and collapse of these buildings in the September 2017 earthquake can be explained by the effect of cumulative seismic damage. Recommendations are given for possible improvements to the seismic building codes in Mexico.

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

Earthquake Spectra ◽

10.1193/1.1585510 ◽

1989 ◽

Vol 5 (1) ◽

pp. 41-50 ◽

Cited By ~ 1

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.

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

Earthquake Spectra ◽

10.1193/1.1585521 ◽

1989 ◽

Vol 5 (1) ◽

pp. 249-255 ◽

Cited By ~ 1

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.

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

Earthquake Spectra ◽

10.1193/1.1585517 ◽

1989 ◽

Vol 5 (1) ◽

pp. 153-174 ◽

Cited By ~ 12

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.

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

Earthquake Spectra ◽

10.1193/1.1585516 ◽

1989 ◽

Vol 5 (1) ◽

pp. 145-151 ◽

Cited By ~ 15

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.

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

Earthquake Spectra ◽

10.1193/1.1585518 ◽

1989 ◽

Vol 5 (1) ◽

pp. 175-193 ◽

Cited By ~ 7

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.

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

Earthquake Spectra ◽

10.1193/1.1585486 ◽

1988 ◽

Vol 4 (3) ◽

pp. 469-479 ◽

Cited By ~ 1

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.

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

Earthquake Spectra ◽

10.1193/1.1585515 ◽

1989 ◽

Vol 5 (1) ◽

pp. 121-143 ◽

Cited By ~ 10

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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