Mezcala Bridge
Encyclopedia
The Mezcala Bridge is a cable-stayed
bridge
located in the state of Guerrero
on Highway 95
in Mexico
. It spans the Balsas River
(known locally as the Mezcala River) close to the western Pacific coast
of the country. This bridge, with a total length of 891 m (2,923.2 ft) and six uneven span
s completed in 1993, has been in service since 1994 as a toll bridge
. When built, it was considered to be 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.
and the port of Acapulco to about 3.5 hours.
However, this rerouting of the highway required crossing of the Balsas River (also known as the Mezcala River at a location (150 km (93.2 mi)from Cuernavaca
) where the river width from bank to bank varied from 800 metre. The hill slopes on the banks were also found to be steep. Consequently, the Mezcala bridge was planned and designed to cross the river. This bridge is also known by the name "Mezcala-Solidaridad" bridge.
In 2010, as part of Mexico's celebrations for its bicentennial
, 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
and Acapulco
. The route commemorated a military campaign led by José María Morelos
.
(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
, 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 160 m (524.9 ft) deep. The bridge consists of six spans, with lengths of the spans in the following order: 42 m (137.8 ft), 69 m (226.4 ft), 86 m (282.2 ft), 301 m (987.5 ft), 313 m (1,026.9 ft), and 80 m (262.5 ft), for a total length of 891 m (2,923.2 ft).
and the China Communications and Transportation Association indicated that the High-density polyethylene (HDPE) sheathing, which has hydrocarbon
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."
Cable-stayed bridge
A cable-stayed bridge is a bridge that consists of one or more columns , with cables supporting the bridge deck....
bridge
Bridge
A bridge is a structure built to span physical obstacles such as a body of water, valley, or road, for the purpose of providing passage over the obstacle...
located in the state of Guerrero
Guerrero
Guerrero officially Estado Libre y Soberano de Guerrero is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is divided in 81 municipalities and its capital city is Chilpancingo....
on Highway 95
Mexican Federal Highway 95
Mexican Federal Highway 95 connects Mexico City to Acapulco, Guerrero.The highway is the main road that leads to the Lagunas de Zempoala National Park...
in Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
. It spans the Balsas River
Balsas River
The Balsas River is a major river of south-central Mexico. The basin flows through the states of Puebla, Morelos, Guerrero, and Mexico. The river empties into the Pacific Ocean at Mangrove Point, adjacent to the city of Lázaro Cárdenas, Michoacán...
(known locally as the Mezcala River) close to the western Pacific coast
Pacific Coast
A country's Pacific coast is the part of its coast bordering the Pacific Ocean.-The Americas:Countries on the western side of the Americas have a Pacific coast as their western border.* Geography of Canada* Geography of Chile* Geography of Colombia...
of the country. This bridge, with a total length of 891 m (2,923.2 ft) and six uneven span
Span (architecture)
Span is the distance between two intermediate supports for a structure, e.g. a beam or a bridge.A span can be closed by a solid beam or of a rope...
s completed in 1993, has been in service since 1994 as a toll bridge
Toll bridge
A toll bridge is a bridge over which traffic may pass upon payment of a toll, or fee.- History :The practice of collecting tolls on bridges probably harks back to the days of ferry crossings where people paid a fee to be ferried across stretches of water. As boats became impractical to carry large...
. When built, it was considered to be 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 263 km (163.4 mi) length was drawn which reduced the distance by 49 km (30.4 mi) between Cuernavaca and Acapulco, and also reduced the travel time between México CityMexico City
Mexico City is the Federal District , capital of Mexico and seat of the federal powers of the Mexican Union. It is a federal entity within Mexico which is not part of any one of the 31 Mexican states but belongs to the federation as a whole...
and the port of Acapulco to about 3.5 hours.
However, this rerouting of the highway required crossing of the Balsas River (also known as the Mezcala River at a location (150 km (93.2 mi)from Cuernavaca
Cuernavaca
Cuernavaca is the capital and largest city of the state of Morelos in Mexico. It was established at the archeological site of Gualupita I by the Olmec, "the mother culture" of Mesoamerica, approximately 3200 years ago...
) where the river width from bank to bank varied from 800 metre. The hill slopes on the banks were also found to be steep. Consequently, the Mezcala bridge was planned and designed to cross the river. This bridge is also known by the name "Mezcala-Solidaridad" bridge.
In 2010, as part of Mexico's celebrations for its bicentennial
Celebration of Mexican political anniversaries in 2010
In 2010, Mexico celebrated both the 200th anniversary of its Independence and 100th anniversary of its Revolution. The entire year was proclaimed by President Felipe Calderón as "Año de la Patria", or "Year of the Nation." 16 September 1810 is the day of the "Grito de Dolores" or Miguel Hidalgo's...
, 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
Mexico City is the Federal District , capital of Mexico and seat of the federal powers of the Mexican Union. It is a federal entity within Mexico which is not part of any one of the 31 Mexican states but belongs to the federation as a whole...
and Acapulco
Acapulco
Acapulco is a city, municipality and major sea port in the state of Guerrero on the Pacific coast of Mexico, southwest from Mexico City. Acapulco is located on a deep, semi-circular bay and has been a port since the early colonial period of Mexico’s history...
. The route commemorated a military campaign led by José María Morelos
José María Morelos
José María Teclo Morelos y Pavón was a Mexican Roman Catholic priest and revolutionary rebel leader who led the Mexican War of Independence movement, assuming its leadership after the execution of Miguel Hidalgo y Costilla in 1811...
.
Design features
The innovative main concept of this bridge, featuring four adjacent main spans sustained by three consecutive harps of stays (with three tall towers and with the central tower being the central main pylon (pier) of 173 m (567.6 ft) in height, was designed by Mexican engineer Modesto Armijo, head of the Mexican company "COMEC SA", for the account of the federal Secretaría de Comunicaciones y TransportesSecretariat of Communications and Transportation (Mexico)
The Secretariat of Communications and Transportation of Mexico is a federal entity that regulates commercial road traffic and broadcasting...
(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
In the fields of architecture and civil engineering, construction is a process that consists of the building or assembling of infrastructure. Far from being a single activity, large scale construction is a feat of human multitasking...
, 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 160 m (524.9 ft) deep. The bridge consists of six spans, with lengths of the spans in the following order: 42 m (137.8 ft), 69 m (226.4 ft), 86 m (282.2 ft), 301 m (987.5 ft), 313 m (1,026.9 ft), and 80 m (262.5 ft), for a total length of 891 m (2,923.2 ft).
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 EngineersAmerican Society of Civil Engineers
The American Society of Civil Engineers is a professional body founded in 1852 to represent members of the civil engineering profession worldwide. It is the oldest national engineering society in the United States. ASCE's vision is to have engineers positioned as global leaders who strive toward...
and the China Communications and Transportation Association indicated that the High-density polyethylene (HDPE) sheathing, which has hydrocarbon
Hydrocarbon
In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons from which one hydrogen atom has been removed are functional groups, called hydrocarbyls....
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."