The Mezcala Bridge (also known as the Mezcala-Solidaridad Bridge), is a
cable-stayed bridge
A cable-stayed bridge has one or more ''towers'' (or ''pylons''), from which cables support the bridge deck. A distinctive feature are the cables or stays, which run directly from the tower to the deck, normally forming a fan-like pattern ...
located in the state of
Guerrero
Guerrero is one of the 32 states that comprise the 32 Federal Entities of Mexico. It is divided in 81 municipalities and its capital city is Chilpancingo and its largest city is Acapulcocopied from article, GuerreroAs of 2020, Guerrero the pop ...
on
Highway 95D in
Mexico
Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ...
. It spans the
Balsas River
The Balsas River (Spanish Río Balsas, also locally known as the Mezcala River, or Atoyac River) is a major river of south-central Mexico.
The basin flows through the states of Guerrero, México, Morelos, and Puebla. Downstream of Ciudad Alta ...
(known locally as the Mezcala River) close to the western
Pacific coast of the country. This bridge, with a total length of and six uneven
span
Span may refer to:
Science, technology and engineering
* Span (unit), the width of a human hand
* Span (engineering), a section between two intermediate supports
* Wingspan, the distance between the wingtips of a bird or aircraft
* Sorbitan ester ...
s completed in 1993, has been in service since 1994 as a
toll bridge
A toll bridge is a bridge where a monetary charge (or '' toll'') is required to pass over. Generally the private or public owner, builder and maintainer of the bridge uses the toll to recoup their investment, in much the same way as a toll road ...
.
It was the world's ''tallest'' bridge from its opening in 1993 to 1998 when the
Akashi-Kaikyo Bridge
The is a suspension bridge which links the city of Kobe on the Japanese island of Honshu to Iwaya on Awaji Island. It is part of the Kobe-Awaji-Naruto Expressway, and crosses the busy and turbulent Akashi Strait (''Akashi Kaikyō'' in Japanese ...
in Japan was opened. It was also the ''highest'' bridge in Mexico and the second highest multiple cable-stayed bridge to be built in the world.
The Mezcala Bridge was built as part of the 1989–1994 highway restructuring program in Mexico, which reduced the distance of Highway 95 between Cuernavaca and Acapulco by 49 km.
The bridge suffered a fire in one of its cable systems in March 2007 when there was an accident on the main deck. The fire resulted when a coconut-carrying truck collided with two school buses. The bridge was only partially closed until the damaged cable was replaced.
History
A new national highway program was initiated in Mexico between 1989 and 1994. Under this program, the federal highway "Cuernavaca - Acapulco", also called the "Route of the Sun", was proposed to be re-routed to reduce the distance, as well as travel time. A new planned route of length was drawn which reduced the distance by between Cuernavaca and Acapulco, and also reduced the travel time between
México City
Mexico City ( es, link=no, Ciudad de México, ; abbr.: CDMX; Nahuatl: ''Altepetl Mexico'') is the capital and largest city of Mexico, and the most populous city in North America. One of the world's alpha cities, it is located in the Valley o ...
and the port of Acapulco to about 3.5 hours.
[
This rerouting of the highway, however, required crossing of the Balsas River (also known as the ]Mezcala River
The Balsas River (Spanish Río Balsas, also locally known as the Mezcala River, or Atoyac River) is a major river of south-central Mexico.
The basin flows through the states of Guerrero, México, Morelos, and Puebla. Downstream of Ciudad Al ...
) at a location ( from Cuernavaca
Cuernavaca (; nci-IPA, Cuauhnāhuac, kʷawˈnaːwak "near the woods", ) is the capital and largest city of the state of Morelos in Mexico. The city is located around a 90-minute drive south of Mexico City using the Federal Highway 95D.
The na ...
where the river width from bank to bank varied from . The hill slopes on the banks were also found to be steep. Consequently, the Mezcala bridge was planned and designed to cross high over the river. This bridge is also known by the name "Mezcala-Solidaridad" bridge.[
In 2010, as part of Mexico's celebrations for its ]bicentennial __NOTOC__
A bicentennial or bicentenary is the two-hundredth anniversary of a part, or the celebrations thereof. It may refer to:
Europe
*French Revolution bicentennial, commemorating the 200th anniversary of 14 July 1789 uprising, celebrated ...
, a series of roads were deemed to be part of "Ruta 2010", that commemorated various paths taken during military campaigns. Highway 95 was a part of the path called "The Sentiments of the Nation Route", which included the connection between Mexico City
Mexico City ( es, link=no, Ciudad de México, ; abbr.: CDMX; Nahuatl: ''Altepetl Mexico'') is the capital city, capital and primate city, largest city of Mexico, and the List of North American cities by population, most populous city in North Amer ...
and Acapulco. The route commemorated a military campaign led by José María Morelos
José María Teclo Morelos Pérez y Pavón () (30 September 1765 – 22 December 1815) was a Mexican Catholic priest, statesman and military leader who led the Mexican War of Independence movement, assuming its leadership after the execution of ...
.
Design features
The innovative overall concept of this bridge featured four adjacent main spans sustained by three consecutive harps of cable stays attached to three tall towers, with the central tower being the central main pylon (pier) of in height. The overall design was by Mexican engineer Modesto Armijo, head of the Mexican company "COMEC SA", for the account of the federal Secretaría de Comunicaciones y Transportes
The Secretariat of Infrastructure, Communications and Transportation (''Secretaría de Infraestructura, Comunicaciones y Transportes'', SICT) of Mexico is the national federal entity that regulates commercial road traffic and broadcasting. Its he ...
(''Secretariat of Communications and Transportation''). The detailed design was also achieved by Modesto Armijo and Alain Chauvin from "COMEC, S.A.". While COMEC did the structural engineering design, the engineering designs were checked by EEG Europe Etudes Gecti and the cables were supplied by Freyssinet International.
The calculation of the static and dynamic effects of turbulent wind on the bridge, when in service and under construction
Construction is a general term meaning the art and science to form Physical object, objects, systems, or organizations,"Construction" def. 1.a. 1.b. and 1.c. ''Oxford English Dictionary'' Second Edition on CD-ROM (v. 4.0) Oxford University Pr ...
, was carried out using the "Scanner" computer program, taking into account the aerodynamic measurements made at the Carmel West Wind Laboratory (J. Raggett) on a model of the bridge deck, with the help of Pr Scanlan. Careful studies of the behavior of this bridge under seismic conditions were also carried out using the same computer program.[
The valley over which the bridge passes is approximately deep. The bridge consists of six spans, with lengths of the spans in the following order: , , , , , and , for a total length of .]
Construction material
The bridge is categorized as a cable-stayed bridge, and has H-pylon supports with semi-fan arrangement. The piers of the bridge were constructed with reinforced cement concrete. Both the superstructure and the cable are made of steel. Cable supported concrete pylon was adopted due to high seismic conditions of the area.
Failure event
The multispan stayed or cable bridge suffered damages to one of the stay cables with a minor damage to an adjoining cable during a fire that was created due to an accident on March 17, 2007, between two school buses and a truck at the middle span of the bridge. The truck was carrying coconuts, which was the reason for the fire. After closing the bridge for vehicular traffic temporarily, the cable was replaced; though traffic was partially restored when the cable replacement started. Analysis of the cause of the fire by the American Society of Civil Engineers
American(s) may refer to:
* American, something of, from, or related to the United States of America, commonly known as the "United States" or "America"
** Americans, citizens and nationals of the United States of America
** American ancestry, pe ...
and the China Communications and Transportation Association indicated that the High-density polyethylene
High-density polyethylene (HDPE) or polyethylene high-density (PEHD) is a thermoplastic polymer produced from the monomer ethylene. It is sometimes called "alkathene" or "polythene" when used for HDPE pipes. With a high strength-to-density ratio, ...
(HDPE) sheathing, which has hydrocarbon
In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons are examples of group 14 hydrides. Hydrocarbons are generally colourless and hydrophobic, and their odors are usually weak or ...
composition, was not ideally fire resistant as it caught fire and created the additional fire load which resulted in snapping of one cable line. A moot question that was posed in the analysis was "would this bridge have survived the loss of two or three adjacent cables?" Analysis also showed that multiple cables could be included in a fire caused by a lightning strike.
Bridge designers have examined the lacunae in design of major long span bridges of various types in the world, keeping in view the failures that have occurred in many bridges including the limited failure of the cable of the Mezcala Bridge due to a single point loading event that occurred due to a fire. This study was done with the objective "to enhance the reliability and safety of these major structures in the built environment." The approach now under consideration for cable stayed bridge is "a more rational approach from assigning factors of safety to key elements such as suspenders and stay cables, to setting depth and stiffness requirements."[
]
See also
*List of tallest bridges in the world
This list of tallest bridges includes bridges with a structural height of at least . The of a bridge is the maximum vertical distance from the uppermost part of a bridge, such as the top of a bridge tower, to the lowermost exposed part of the br ...
References
{{Reflist, 2
Cable-stayed bridges in Mexico
Bridges completed in 1993
Buildings and structures in Guerrero
Transportation in Guerrero
Toll bridges in Mexico