Significant Concrete and Steel Structures of the World

Group 5:Kate Bonn

Matt ChaneyNick Chaney

Obinnna Ekweremuba

CEEN 5849Spring 2010

Hoover DamThe Hoover Dam is a significant concrete structure in the United States. The

Hoover Dam, once known as Boulder Dam, is located in the Black Canyon of the Colorado River. This is on the border of Arizona and Nevada, thirty miles southeast of Las Vegas.

The Hoover Dam was built because the Colorado River was powerful and destructive. Many attempts were made to contain the mighty river, but all failed. The Bureau of Reclamation was asked to design a solution and they suggested building a dam. The director, Arthur Davis, proposed an extremely high dam near the beginning of the lower basin. Herbert Hoover helped the river basin states reach an agreement on allocating water to each state. For this achievement, the dam was named after him. In 1928, Congress passed the Boulder Canyon Act assigning money to build the project.

When the construction of the dam was authorized in 1928, the Bureau immediately got to work. Geologists, surveyors, and engineers analyzed the land and began the design process. The chosen design for the Hoover Dam involved two systems: the arch system and the gravity system. In 1931, the bid by Six Companies, Inc. for building the Hoover Dam was accepted and construction began. With the extreme size of the dam came many construction problems. Housing for workers, the shipment and storing of large quantities of materials, and appropriate drilling machinery were only a few of the challenges the contractors had to face. However, for each challenge they found the solution and construction continued. There were three major segments of the dam’s construction: the diversion tunnels and penstocks, the concrete-arched structure, and the power plant.

Two cofferdams were built to protect the construction site from flooding and four diversion tunnels were constructed to divert the river’s flow around the construction site. The intent was for the dam to rest on solid rock, so 1,500,000 cubic yards of material was excavated. Since the design of the dam was a gravity-arch type, the side walls of the canyon had to be excavated too, to reach un-weathered rock. The men who removed the rock were suspended from the top of the canyon with ropes and removed the loose rock with jackhammers and dynamite. The first concrete was placed in June, 1933. It was calculated that if the dam were built in a single pour it would take 125 years to cool. So the Bureau’s solution was to build the dam in a series of interlocking trapezoidal concrete pours. To aid in the cooling, each form contained cooling coils of steel pipe. First, river water was circulated through the pipes. Then, chilled water from a refrigeration plant on site was circulated through the coils to further cool the concrete. According to the Lower Colorado Bureau of Reclamation: Hoover Dam, Facts and Figures, “there is enough concrete in the dam to pave a two-lane highway from San Francisco to New York.”

There were 112 deaths associated with the construction of the dam. Many of the men who worked in the tunnels suffered from the carbon monoxide generated by the machinery. Contractor’s claimed the sickness was pneumonia and not their responsibility. Most of those who died from the carbon monoxide poisoning are not counted on the official death list.

The U-shaped power plant is located at the downstream toe of the dam. The total gross power rating for the plant is approximately 2080 megawatts. The significant power generation allowed the dam to be self-sustaining.

The original design for the facade of the dam and power plant was criticized for being too plain, so Los Angeles architect, Gordon Kaufmann, was hired to redesign the exteriors. Kaufmann streamlined the buildings and applied an Art Deco style to the project.

The job was impressively completed two years ahead of the construction target. The total construction cost was $49 million which has been easily repaid by the dam’s enormous production of energy. The final dimensions of the structure were 726.4 feet high, 660 feet wide at the base, 45 feet wide at the top, and a crest length of 1,244 feet.

Aerial view of the Hoover Dam

Roman ColiseumThe Roman Coliseum is a significant concrete structure in Italy. The Colosseum,

once known as the Flavian Amphitheater, is located in the center of the city of Rome, Italy. It is elliptical in shape and the largest ever built in the Roman Empire. The Roman Coliseum is one of the greatest works of roman architecture and engineering.

Construction started between 70 and 72 AD under the emperor Vespasian and was completed in 80 AD under his son, Titus. The building was further remodeled under Vespasian’s younger son, Domitian. The Colosseum has tiers of seating for 50,000 spectators. Spectators came to watch gladiatorial contests and public spectacles such as animal hunts, executions, and dramas based on Classical mythology. It has been estimated that approximately 500,000 people and a million wild animals died in the Colosseum games. In the early medieval era, the building was no longer used for entertainment and instead was used for housing, workshops, a quarry, and religious purposes. The Colosseum suffered a lot of damage from fires and earthquakes. It has had numerous restorations over time. Today, the structure remains partially ruined due to earthquakes. However, it is still one of Rome’s most popular tourist attractions. In recent years it has become a symbol of the international campaign against capital punishment.

The Colosseum is an entirely free-standing structure. It derives its architecture from that of two Roman theaters back-to-back. The Colosseum is 189 meters long and 156 meters wide, with a base area of 24,000 m2. The height of the outer wall is 48 meters. The perimeter originally measured 545 meters. The central arena is an oval with dimensions 287 feet long by 180 feet wide, surrounded by a wall that is 15 feet high. The architects designed the Colosseum to have eighty entrances so the large crowds could enter and exit the building quickly. Below the wooden arena floor, there is a complex set of rooms and tunnels that was used for the wild beasts and other spectacles. At the outer edge, circumferential arcades link each level and the stairways between levels. The three tiers of arcades are faced by three-quarter columns. Above that is an attic story with Corinthian pilasters. Two hundred and forty mast corbels were positioned around the top of the attic to support a retractable awning that kept the sun and rain off spectators. The three tiers of arches and attic story totaled about 48.5 meters tall (approximately equivalent to a 12-15 story building.)

The construction of the Colosseum utilized a combination of types: concrete for the foundations, travertine for the piers and arcades, tufa infill between piers for the walls of the lower two levels, and brick-faced concrete for the upper levels and most of the vaults. The design of the Colosseum applied the latest in Roman arts, engineering, and architecture. The invention of concrete enabled this massive building to be built quickly, efficiently and to great effect.

The construction cost of the Colosseum is unknown, but in 70 A.D. Titus had invaded the city of Jerusalem and used the fabulous treasures of Jerusalem to pay for the building of the Colosseum. It is estimated that 100,000 prisoners were bought back to Rome as slaves after the Jewish War. Vespasian used the slaves as his work force. The slaves undertook the manual labor, while teams of professional Roman builders, engineers, artists, painters and decorators undertook the skilled tasks.

Roman architecture and buildings were strongly influenced by concrete and vaulted arches. Concrete was a recent invention when the Colosseum was built and the Romans were still learning how to use it. The Romans cautiously combined concrete with

stone. The ceilings of the passages and corridors in the Colosseum consisted of vaulted arches made of concrete. The vaulted arches made the ceilings much stronger than a flat ceiling would have been. Because the vaulted arches were made of concrete, they added strength to the building without adding excessive weight. Without concrete and vaulted arches, the Colosseum could not have been built.

Exterior of the Colosseum

San Francisco Federal BuildingThe San Francisco Federal Building is a significant steel structure in the United

States. It is a federal office building located on 7th Street in San Francisco, California. The Federal Building is considered one of the most green buildings in America due to its energy efficiency. The elevator only stops on every third floor, forcing the workers to take the stairs. There is no air conditioning, rather an automatic adjusting ventilation system which naturally feeds the air into the building – the first on the west coast. The building also has a perforated steel scrim which is used to filter sunlight to prevent overheating of the inside of the building. It is stated that the Federal Building only uses 45% of the energy that an average General Services Administration (GSA) building uses.

The Federal Building was designed by Thom Mayne of the architectural firm, Morphosis. The building has 18 floors of office space and stands 234 feet tall. The building was expected to be completed by 2005, but construction delays pushed the project completion to 2007. The construction cost was $144 million. The size of the building is 652,000 gross square feet. The building houses approximately 1,500 federal employees of the Departments of Labor, Health and Human Services, Agriculture, and Defense. The project is part of a process of urban renewal in a transitional neighborhood.

According to the Morphosis’ website, the three primary objectives of the project include, “the establishment of a benchmark for sustainable building design through the efficient use of natural energy sources; the redefinition of the culture of the workplace through office environments that boost workers’ health, productivity, and creativity; and the creation of an urban landmark that engages with the community.” The layout of the building locates open work areas at the building perimeter and private offices and conference spaces at the center. The intermittent elevators, sky gardens, open stairwells, and elimination of corner offices promote people interaction.

The building provides natural ventilation to 70% of the work area and natural light and operable windows to 90% of the workstations. A folded, perforated metal sunscreen shades the full-height glass window wall system and a mutable skin of computer–controlled panels adjusts to daily and seasonal climate fluctuations. The 3-foot-by-8-foot stainless-steel panels, which appear translucent, are supported in front of the all-glass building wall by a metal framework. Functionally, they shade the building from low winter sun, cutting daylight to a comfortable level for office workers.

The San Francisco Federal Building establishes a benchmark for sustainable design in its use of natural energy sources.

Photograph of the finished Federal Building

Eiffel TowerThe Eiffel Tower is a significant steel structure in France. The Eiffel Tower is

located on the Champ de Mars in Paris, France. The tower was designed by Gustave Eiffel as the entrance arch for the 1889 World’s Fair. The Eiffel Tower is the tallest building in Paris and the single most visited paid monument in the world. It has become the most renowned symbol of both Paris and France.

The tower is 1, 063 feet tall and weighs approximately 10,000 tons. The metal structure of the tower weighs 7,300 tons and has a relatively low density. Eiffel originally planned to build the tower in Barcelona, but it was refused for being a strange and expensive construction which did not fit the city. Paris accepted Eiffel’s submission for the Universal Exhibition in Paris and construction began in 1887. Three hundred workers gathered to build Maurice Koechlin’s structural design. The tower consists of 18,038 pieces of puddled iron joined together by a half million rivets. Construction was dangerous because the frame is open and there are only two platforms in the entire structure. However, Eiffel took serious safety precautions and only one man died. Construction was completed in 1889. There are three levels to the Eiffel Tower. The first two can be accessed by stairs. The third, topmost tower is only accessible by elevator.

All the elements for construction were prepared in Eiffel’s factory located on the outskirts of Paris. Each piece was measured to an accuracy of a tenth of a millimeter. The pieces were first assembled in the factory using bolts. Later, they were replaced one by one with thermally assembled rivets. The rivets contracted during cooling, ensuring a tight fit. A four man team was needed to assemble each rivet. Concrete foundations were installed a few meters below ground for the uprights to rest on. The foundations only took five months to build. The tower was built using wooden scaffolding. The pieces were hauled up using steam cranes which were mounted onto the tower itself. It took twenty-one months to assemble the tower – a remarkably fast construction considering the means available at that time. The cost of construction was $150 million. Maintenance of the tower includes applying 50 to 60 tons of paint every seven years to protect it from rust.

The Eiffel Tower was built to celebrate the science and engineering achievements of its age. The structure consists of a base composed of a platform resting on four separate supports. Above this is a slender tower that tapers upward into a unified column. The size of the base area is 2.54 acres. Eiffel was the leading European authority on the aerodynamics of high frames. The curve of the base pylons in the Eiffel tower was precisely calculated so that the bending and shearing forces of the wind were transformed into forces of compression that the structure could withstand. In the strongest winds, the Eiffel Tower never sways more than 4 ½ inches.

The Eiffel Tower is now owned by the City of Paris. Since the 20th century, the tower has been used for radio transmission. More than 500 people bring the Eiffel Tower to life each day. The Eiffel Tower has been the inspiration for dozens of similar towers around the world.

Eiffel Tower at night

References

http://en.wikipedia.org/wiki/Eiffel_tower

http://en.wikipedia.org/wiki/Hoover_Dam

http://en.wikipedia.org/wiki/Roman_Coliseum

http://en.wikipedia.org/wiki/San_Francisco_Federal_Building

http://open.salon.com/blog/jd_rucker/2009/07/31/structural_skeletons_5_famous_steel_buildings

http://www.discoverfrance.net/France/Paris/Monuments-Paris/Eiffel.shtml

http://www.govexec.com/pdfs/green/080108gsa.pdf

http://www.greatbuildings.com/buildings/Roman_Colosseum.html

http://www.morphopedia.com/projects/san-francisco-federal-building

http://www.roman-colosseum.info/colosseum/building-the-colosseum.htm

http://www.romanconcrete.com/docs/hooverdam/hooverdam.htm

http://www.tour-eiffel.fr/teiffel/uk/documentation/dossiers/page/construction.html