Federal District Building Regulations
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The building regulation before the 1985 earthquake
Before the earthquake of 1985 Mexico City was affected by 23 earthquakes with a magnitude greater than 7 in the Ritcher scale. However, none had been as devastating as the one experienced on September 1985, whose magnitude reached 8.1 on the Ritcher scale. The magnitude of this earthquake in relation to people and the building concentration, as well as the lack of compliance to building regulations, resulted in enormous damages and considerable human and material losses within Mexico City. For this reason, the building regulation of the Federal District (DF) and the supervision of its implementation, constituted one of the main topics in the public debates after the earthquake. Also, this event raised issues related to corruption, negligence, lack of efficiency, violations to this regulation, and an insufficient legislation. All these problems became a great pressure for the authorities to modify the building regulation (Poloniato and Rodríguez, 1987: 90).
The building regulation implemented before the earthquake of 1985 had been approved on December 1976. There was a group of experts that after the ‘85 earthquake considered the 1976 standards as effective and appropriate as any other building code in the developing countries, since it included the seismic norms and incorporated some measurements for building foundations (Granillo, 1985: 36). Nevertheless, other specialists believed that this building regulation was not effective for mitigating consequences of the seismic activities and reducing the human and material losses. The reasons for the inefficiency of this regulation, as suggested by this second group were the following:
- This building regulation did not include measurement for increasing the seismic resistance of the buildings, in case of occurrence of earthquakes with a magnitude higher than 7 on the Ritcher scale.
- The construction of buildings or houses was allowed in the high seismic risk zones even though those houses had already been identified in a hazardous zone during an earthquake that took place in the City in 1957.
- The building regulation did not clearly define the magnitude of earthquakes that construction must support, and, also, it did not define the exposure of the seismic activities in different areas that constituted the city.
- The construction of houses and buildings did not have external supervision of specialists in charge of making the building regulation to be implemented in those aspects related to the design and the dimensions approved
- Houses and buildings did not have external supervision for verifying that they were not built with materials of low quality.
- The building regulation did not clearly define the characteristics of the foundations and the structures of the constructions.
- The authorities did not request the giving buildings license an analysis of the geologic characteristics of the area in which they would be built. For this reason, they allowed the construction of houses and buildings in areas considered as highly exposed to seismic activity
This regulation did not establish the duties of the owners and the users of the properties, and it did not clearly define the sanctions for no compliance of building regulations related to land use, design, dimensions, structure and materials, among others. For example, if the construction had been designed for residential units, but they were used as factories, offices, or storerooms, this situation overloaded the structures and increased the vulnerability of the building to seismic movements, such as the earthquake of 1985 (De Buen, 1985).
On the other hand, the structures of some properties, like the Continental Hotel or the Nonoalco-Tlatelolco residential unit, had already been affected by the previous earthquakes. However, their supervision and repairmen always were superficial; therefore they did not guarantee the safety of their residents and when the city was affected by the earthquake of 1985, and they collapsed (Gonzalez Prado, l985).
Many buildings collapsed in the earthquake of 1985 because they were built with bad quality materials to increase the earnings of the builders. For this reason, the authorities after the disaster caused by the earthquake, investigated who were responsible for not fulfilling the building regulation in order to punish them. Nevertheless, the actions implemented for finding the responsibles of such aggravating factor that eventually increased the magnitude of material and human losses of the 1985 earthquake were stopped and forgotten, and the authorities recognized as the main cause of the impacts of this seismic event, the lack of specifications in the building regulations (Poloniato and Rodríguez, 1987: 27).
Some of the violations of the building regulation approved before the earthquake of 1985 were the following:
- The minimum specified separation between houses and building was not respected, since the builder wanted to have more space for constructing bigger houses and apartments. This space, known as the seismic colindancy, is meant to avoid pounding of neighbouring structures due to the seismic movement. Therefore, the earthquake of 1985 provoked that many buildings collapsed because they crashed with the other buildings nearby.
- The builders modified the original designs, which were approved by the authorities, once they obtained the building license for earning more money. However, the authorities did not know this fact because they did not supervise that the original design was respected.
- The builders used low quality materials to save money, and the structures did not have enough steel as was required, and the foundations were not as solid as it were necessary.
- The buildings were used in activities for which they were not designed. This affected the structures, in turn making them more vulnerable to seismic activities.
- Some buildings did not have emergency stairs even though they had been clearly described in the building regulation.
- Many buildings that collapsed had serious deficiencies in their foundations, floors, and roofs.
- According with the building regulation, it was optional for obtaining the building license, in which a professional assumed the technical responsability of the construction. Nevertheless, this requirement was not fullfilled almost for any of the buildings that collapsed during the earthquake of 1985 (Ojeda, 1985).
For reducing the occurrence and the magnitude of seismic disasters, it is necessary to analyze the geologic characteristics before starting construction. Then, the design and the structure of any kind of construction has to consider this information, in order for the houses or buildings to support the roofs, walls, floors, furniture, and people. They also need to be able to resist high winds, earthquakes, explosions, and sinking. All these variables were ignored in the building regulation previous to the earthquake of 1985 and for this reason, it was modified.
Modifications in the building regulation after the earthquake of 1985
Some months after the earthquake of 1985, the Emergency Norms for Structural Security was published; this publication contained important modifications for increasing the security in the buildings and houses. In 1987, the building regulation had some technical modifications and new measures in the construction process for increasing the security of the houses and buildings once they were finished.
Some of these modifications established as an obligatory requirement for obtaining the building license was that a professional assumed the technical responsibility for the construction. This professional would be in charge for fulfilling the building regulation. Therefore, with this modification, the legal figure known as co-responsibility in the structural security and in the architectonic design was incorporated to the legal framework related to the construction. After this year, the building regulation is constantly adjusted for incorporating the advances in the new building techniques and materials, and in the new approaches in the structural designs.
In 2003, the building regulation was modified again with the purpose of incorporating the innovations in buildings design, materials, and structures. This also included the new information related to the seismic activity and the geological characteristics of the landscape. The new modifications in the building regulation and the publication of the Complementary Technical Norms were completed with the cooperation among the Federal District Government and diverse academic and professional institutions like the Federal District Structural Security Committee, the Civil Protection Commission, the Ministry of Urban Development and Environment, the Ministry of Housing, the Ministry of Work, and the Technical Society of Engineering, among others.
The most important modifications related to the disaster prevention in the building regulation can be classified in three groups:
- Improvements in the administrative efficiency
- Improvements in the security measures
- Incorporation of the building advances
The improvements in the administrative efficiency are related to the reduction in the steps required in the legal process for obtaining a building license and the construction being approved by the authorities, and it is also related to fulfilling the building regulation.
- The "Building Manifestation" is a declaration signed by the owners, the tenants, and the responsible agents during the construction, in which they assume and recognize their responsibility for fulfilling the dispositions established in the building regulation and other norms related to this regulation. With this manifestation, an important administrative simplification was carried out for obtaining the building licence and the other requirements in the Federal District.
- The people responsible for the construction have more duties for fulfilling the building regulation because they are considered as the supervisors and managers of the correct application of this regulation. If they do not guarantee that this regulation be fulfilled, they will receive severe administrative and pecuniary sanctions.
- The installation of announcements and all kinds of antennas in the roofs required the signing of the person responsible for the building, who will supervise and guarantee the safety of the people.
The incorporation of the building Knowledge is related to the incorporation of the scientific and technological advances in the building field to the building regulation.
- The new building regulation incorporates many advances related to the construction. In particular, this regulation considers the seismic coefficients of floors and the geological characteristics of the land. These measures reduce the vulnerability of the structures for the seismic activity.
- This regulation also incorporates the new designs with concrete of high resistance that increases the durability of the structures and the stability of the building structure. The use of the concrete with high resistence requieres less maintenance and it better resists the actions of the environment.
- The limited space among buildings has implicated that the new constructutions be higher. Therefore it has been necesary to develop mechanisms for the seismic ativity not to damage the new buildings. These mechanisms for the spread of energy are appliances of the structure and absorb the energy produced by the seismic waves, reducing the posible damages to the construction.
- The proliferation of masonry pieces with different geometric forms has given origin to studies and investigations related to new ways for rehearsing the constructions and guaranteeing an appropriate structure that supports different loads and reduces the impacts for seismic movements with different magnitudes.
- To make the structures of the buildings more solid and resistant to seismic movements, their structures must be built with steel and concrete. Particularly, those structures like the columns, armours, roofs, and foundations.
The improvements in the security measures are related to the modifications in the constructions that reduce the human and material losses caused by seismic events.
- The new constructions have to fulfil the architectural requirements in regard to the accessibility and displacement for people with specials needs.
- The new building regulation considers the risks related to fires. Therefore, the constructions need to fulfil certain requirements that diminish a fire event considering the characteristics of the construction, its use, and its occupation.
- This regulation included a new classification for the lake’s floor known as area III because this kind of floor has important geological differences that amplify the seismic waves. For this reason, it includes the different seismic coefficients according with the land characteristics.
- The new building regulation clearly establishes the characteristics that the irregular structures should consider in their designs, their elevation and their structure rigidity.
- De Buen, Oscar (1985), “Entrevista”, Uno Mas Uno, 30-IX-1985, Mexico.
- DDF (1993), “Reglamento de Construcciones para el Distrito Federal”, Gaceta Oficial del Departamento del Distrito Federal, Mexico.
- ___ (1987), “Reglamento de Construcciones para el Distrito Federal”, Gaceta Oficialdel Departamento del Distrito Federal, Mexico.
- GDF (2003), “Reglamento de Construcciones para el Distrito Federal”, Gaceta Oficial del Gobierno del Distrito Federal, Mexico.
- Gómez, Roberto (1989), “Reglamento de construcciones, in Segob, Memoria del 1er Ciclo de Conferencias sobre prevención de desastres, Mexico, Segob.
- González Prado, José (1985), “Piden actualizar el Código de Construcciones del DF”, Uno Mas Uno, 22-IX-1985, Mexico.
- Granillo Vásquez, Silvia (1985), “El hombre propone, la naturaleza dispone ¿Funciones de un reglamento?”, Información Científica y Tecnológica, no. 10, vol. 7, Mexico, CONACYT. .
- Herrera, Norma (1985), “Sismos y construcciones. Lección para la Ingeniería”, Información Científica y Tecnológica, no. 110, vol. 7, november, CONACYT, Mexico.
- Navarro Pineda, Juan Manuel, et. Al (1985), Carta neotécnica nacional con fines de localización de diversas zonas de riesgo natural, México, IPN.
- Ojeda Mestre, Ramón (1985), “Entrevista”, Uno Mas Uno, 22-IX-1985, Mexico.
- Poloniato Alicia and Lourdes Rodríguez (1987), “Discurso político y emergencia sísmica”, Sociológica, year 2, no. 4, Mexico, UAM.
- Programa de Reconstrucción Habitacional (1986), Atlas técnico de la reconstrucción habitacional, Mexico, PRF/Segob.
- Presidencia de la República (1986), Comisión Nacional de Reconstrucción, México, COPLADE-DDF.
- Tejeda Martínez, A. (1985), “¿Cómo medir un sismo?”, Información Científica y Tecnológica, no. 110, vol. 7, november, Mexico, CONACYT.
Knowledge Base Coding Reference
- Name of the Practice: Federal District Building Regulations
- Contact Person(s): Fabiola Sagrario Sosa Rodriguez
- Contact Address: email@example.com
- Written by: Fabiola Sagrario Sosa Rodriguez, Earthquakes and Megacities Initiative, 3cd Local Intern Program, Mexico City-Mexico