Top 10 US Megastructures

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America is home to some of the most iconic megastructures in the world, driving millions of tourists to the country each year. Home to several iconic...

America is home to some of the most iconic megastructures in the world, driving millions of tourists to the country each year. Home to several iconic construction companies and architects, cities like New York and San Francisco are driving the construction boom as a result of economic growth, driving employment, housing and the need to strengthen current infrastructure routes. We take a look at top 10 megastructures within America which continue to inspire architects and construction workers alike, creating new ideas and solutions for years to come.

10. One World Trade Center

Also known as the ‘Freedom Tower’, built after the September 11 2011 attacks, the One World Trade Center officially opened in 2014 and became the sixth tallest skyscraper in the world, reaching a total height of 1,776ft.

Designed by architect David Childs from Skidmore, Owings and Merrill in New York, the new construction incorporates several security features to ensure the safety of individuals who utilise the rentable space. The build sits on a 18ft concrete base to support the structure from any potential attack, with a steel outer framework and 3ft thick reinforced concrete walls in all walkways and shaft networks. Tishman Realty & Construction led the vital construction work, having worked on the original World Trade Center.

The layout of the building is complex with exterior glass facades, yet the edges at the base are chamfered, transforming the tower so that the centre has become octagonal. The observation deck, located over 100 floors above ground and several eateries have turned the build into a first-class mixed use building for both businesses and visitors to the area. 

Similar to many modern constructions, the build has become increasingly sustainable, with over 80 percent of its waste products which are now recycled. Many internal structural elements have also been built from recycled materials.

9. Empire State Building: New York

Built in the 1930s, the Empire State Building (ESB) is one of the tallest buildings in America at 102 storeys, drawing in thousands of tourists each year. Now listed on the National Register of Historic Places, the building reaches heights of 1,454ft providing stunning views of New York.

Designed to incorporate an art deco style by William F. Lamb from architectural firm Shreve, Lamb & Harmon Associates, the building is constructed with limestone from the Empire Mill situated in Sanders, Indiana, with a lobby traversing three storeys. Built from the top down, the skyscraper incorporates over 6,000 windows, with over 3,000 workers undertaking vital work, alongside contracts The Starrett Brothers and Eken.

Now home to over 100 local businesses, the mixed-use building has undergone extensive renovation works to incorporate world-class technology, such as modern elevators from the Otis Elevator Company, and has become one of the tallest sustainable skyscrapers in the world, obtaining LEED certification in 2011.

The 86th and 102nd floors of the building showcase observation decks which provide full panoramic views, at which the ESB has become a key tourist landmark throughout New York, including a gift shop on the 80th floor.

8. The Central Artery / Tunnel Project

The Central Artery / Tunnel project was one of the most complex projects undertaken within America, in order to reduce congestion and strengthen existing transport infrastructures. The project saw the demolition of the area’s six lane central artery (I-93), which was then replaced with an undergone highway, two bridges and connecting links to Boston’s Logan International Airport and linked downtown Boston to the waterfront.

With funding for the project approved in 1987, the project took approximately 15 years to construct due to opposition, escalating costs and construction difficulties, finally commencing in the 1990s. Over 5,000 workers undertook vital works to ensure the impact to traffic flow remained limited throughout the building work, such as the construction of concrete walls to support the old highway, a bespoke jack to support the railway tracks at South Station and the implementation of horizontal braces.

Constructed by Bechtel Corporation and Parsons Brinckerhoff were responsible for the projects design, alongside engineer Christian Menn who designed the Leonard P. Zakim Bunker Hill Memorial Bridge. The teams worked in collaboration with a multitude of contractors: Skanska USA, Modern Continental, contractors Tutor Perini, Jay Cashman, Obayashi Corporation, J. F. White Contracting and Kiewit.

7. Indianapolis Motor Speedway

With its official launch in 1909, the Indianapolis Motor Speedway became the first racing arena in America and is now one of the most famous racetracks in the world, home to Red Bull Indianapolis GP, the Angie’s List Grand Prix of Indianapolis, NASCAR’s Brickyard 400 and Indianapolis 500.

Envisioned by businessman Carl Fisher, the 2 ½ mile track was originally constructed by approximately 500 workers with crushed rock and tar, which has since been renovated with the use of over 3 million bricks and asphalt, which has been placed on top of the original structure to enable cars to reach top speeds yet guarantee increased levels of safety.

With the capacity to seat around 400,000 citizens at each event through the construction of grandstands and various seating areas, but has been under continual refurbishment and renovation since the 1940s to remain accessible for competitions such as the Formula One World Championship and the United States Grand Prix.

6. The Pentagon: Washington DC

Developed by architects George E. Bergstrom and David J. Witmer, the Pentagon was constructed to accommodate the growing number of military and civilian employees, who were spread across 17 different office buildings. Contractor John McShaine was also commissioned to undertake the construction.

Built at a cost of over $35 billion, the concrete build was swiftly finalised in two years with the use of over 4,000 workers, becoming the largest office building in America, spanning 29 acres and over 17 miles of corridor over four storeys.

The five-sided concrete structure, constructed through over 680,000 tonnes of sand and gravel from the Potomac River has been reconstructed as a result of the September 11 2001 attacks, with the first floor undergoing extensive renovation.

5. Grand Central Station: New York

Rebuilt at the start of the 20th century to accommodate electric trains against a growing metropolis, Grand Central Station has become one of the most stunning megastructures within New York, with strong roots embedded within the city, to which it has been placed on the National Historic Register.

Designed by architects Reed & Stem and Warren & Wetmore alongside chief engineer William Wilgus, the split platform station (over several levels), incorporates 44 platforms and has become the largest station in the world.

The build now incorporates restaurants, retail stores and a museum through an extensive renovation. The use of materials has created a grand station with marble, intricate interior decorations, granite and steel utilised within the station’s construction.

The ceiling has been restored to its former glory, depicting an elaborate skyscape, originally designed by French artist Paul Cesar Helleu and undertaken by Hewlett-Basing Studio alongside Helleu Consulting.

4. Kingda Ka: New Jersey

The impressive rollercoaster, Kingda Ka, situated at Six Flags Great Adventure is the tallest steel rollercoaster in the world at 456ft, reaching top speeds of 128mph in 3.5 seconds through the use of a hydraulic launch mechanism.

Built by Intamin, the rollercoaster opened in 2005 and has become one of the most popular rollercoasters in the region, incorporating four trains to cater for the increased number of thrill seekers. Once they reach the top height of 456ft, “riders descend 418ft back down to Earth in a 270 degree spiral.”

3. Golden Gate Bridge: San Francisco

The Golden Gate Bridge is one of the most iconic megastructures in San Francisco, officially opening in 1937 to provide increased links from the city to Marin County, which was previously only accessible by ferry.

Built at a cost of over $35 million, the suspension bridge was built by McClintic-Marshall Construction Company, which became part of Bethlehem Steel Corporation, alongside engineers Joseph Strauss and Charles Ellis and architects Irving Morrow and Leon Moisseiff.

The bridge incorporates walkways, in addition to six lanes, accessible for pedestrians, vehicle users and cyclists. The iconic colour was selected by Irving Morrow, who is responsible for the iconic walkways and overall design, but worked in collaboration with Ellis who was behind the structural, engineering elements to the megastructure.

With over one million total rivets within the bridge structure, and twin towers which reach heights of nearly 750ft, the bridge successfully links both areas and has provided numerous advantages within the region, boosting the local economy and access within the regions.

2. Willis Tower (formerly the Sears Tower)

Built by architect company Skidmore, Owings and Merrill in the 1970s to accommodate retail giants Sears Roebuck and Company, the concrete and steel high rise building now dominates the Chicago skyline at 110 storeys and has become one of the top 10 tallest megastructures in the world at ***

Constructed at a cost of over $175 billion, the tower has over 16,000 large windows to enable maximum light to enter the building, creating a light and airy space for over 12,000 occupants and 25,000 daily visitors, in addition to polished granite flooring incorporated throughout.

In the 1980s, two television antennas were factored into the tower’s design, which are now home to local broadcasting and radio stations.

Also, incorporated at the tower is a Skydeck, which has become one of the top tourist attractions in Chicago, enabling tourists to see across three different states at 1,353ft. Through extensive renovation work in 2009, the Skydeck now includes ‘the Ledge’ on the 103rd floor, enabling tourists to view the skyline through glass boxes which extend from the build.

Now owned by Blackstone Group, the Willis Tower incorporates several sustainable features, with reduced energy and water consumption per year, in addition to reducing the annual electricity consumption by over 30 percent through sophisticated lighting systems. 

1. Spaceport America: New Mexico

Completing in 2006 and opening to the general public in 2011, Spaceport America is a commercial spaceport based in New Mexico, accommodating a variety of aerospace launch vehicles.

Owned by the New Mexico Spaceport Authority (NMSA), the $200 million Spaceport is home to SpaceX and Virgin Galactic incorporated a variety of teams in the build’s construction. SDV Construction undertook vital works for Spaceport America’s Phase 2 projects, alongside contractors B&D Industries and historic and cultural firms, Van Citters Historic Preservation and Jemez Mountains Research Center, LLC, who worked to ensure reduced impact on the surrounding area, in in turn preserving sites of cultural, historical and archaeological importance. Zia Engineering & Environmental Consultants, LLC were also awarded the contract to support the works undertaken.

Sustainable features have been embedded to ensure the design obtained LEED certification. Built with recycled and/or local materials has ensured the reduction in CO2 emissions, in addition to the use of public transport, such as the public shuttle which has ensured the reduction in visitor travel to the site. Also incorporated is the use of glass curtain walls with low e-glazing, which have been placed within the exterior of the build.

Furthermore, waste water is recycled at a wastewater treatment plant on site, and natural light is utilised through the use of skylights, reducing the level of energy throughout the build.

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Read the January 2017 issue of Construction Global here


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