![]() ![]() 11 by a street that has remained closed to traffic during the reconstruction period. One World Trade is separated from the reminders of Sept. Silverstein’s buildings became less associated with the tragedy because they are separated from the memorial and museum by the new street grid, according to leasing brokers. One World Trade suffered huge cost overruns and was slower to rebuild than the two other office buildings on the site controlled by developer Larry Silverstein, who with investors had leased the World Trade Center for 99 years about one month before the attack. Mr. The plan drew praise from architects and urban planners for restoring streets to the site that had been eliminated by the initial World Trade Center complex. To quantify the environmental impact of sustainable concrete for the structure, an Eco-Efficiency Analysis was conducted, using a methodology validated by NSF International, to compare the specialized EF Technology mixture to a reference mixture.In 2003, New York City and state leaders selected a masterplan by the Polish-born architect Daniel Libeskind, which struck a balance between remembrance and rebuilding a commercial hub. This EF Technology mixture was used for the 38,000 yd3 (29,000 m3 ) of concrete needed for the columns through the first 40 floors. The mixture replaced portland cement with the recycled materials, non-cementitious fillers and specialized admixtures to exceed all the performance targets specified by the One World Trade Center project stakeholders. Through BASF´s Green Sense Concrete mixture optimization service, Eastern Concrete Materials was able to proportion an EF Technology® concrete mixture with 71% cement replacement. According to BASF´s Eco-Efficiency Analysis, 15,838,267 kg of CO2 were prevented in the construction of the building´s first 40 floors. To achieve these concrete properties which, combined, would be a groundbreaking feat, concrete producer Eastern Concrete Materials, Elmwood Park, NJ partnered with admixture supplierīASF Construction Chemicals, Beachwood, OH.īASF´s Green Sense® Concrete program optimizes the concrete formulation to reduce the ecological footprint, conserve resources while increasing the structural strength. No loss in concrete workability during transit and placement.Quantity of portland cement in the mixture: Less than 400 lb/yd3 (240 kg/m3).Port Authority of New York/New Jersey Requirements: Heat of hydration: Not to exceed 160 ☏ (70 ☌).Modulus of elasticity: 7.0 million psi (48 GPa).Over-design for safety: 1,900 psi (13 MPa).Compressive strength: 12,000 psi (83 MPa) 56 days.The 12,000 psi (83 MPa) concrete phase of the project was the most challenging, with the engineers, owners and contractors all having their own requirements and specifications. In addition, extremely high performance concrete was necessary to meet the compressive strength requirements of the steel and concrete structural columns, which ranged from 14,000 psi (97 MPa) to 12,000 psi (83 MPa) for the lower 40 floors and 10,000 psi (69 MPa) to 8,600 psi (59 MPa) for the upper floors. Sustainable design was a central theme to One World Trade Center´s development, with the Port Authority of New York/New Jersey imposing a strict requirement for the replacement of portland cement with recycled materials. Construction of the building, previously dubbed the Freedom Tower, began in April 2006 and, when it is completed in 2013, it will be the tallest building in the U.S. Soaring to a height of 1,776 feet (540-meter), the 2.6-million-sf (242,000-square-meter) building soon to become the new One World Trade Center in the lower Manhattan district of New York City is a marvel of design and engineering. One of the biggest challenges in developing this concrete mixture was meeting the Port Authority of New York/New Jersey´s strict requirement for the replacement of cement. One World Trade Center - New York, New York ![]()
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