Irvine, Calif. — The New York City Buildings Department recently published Buildings Bulletin 2015-036, allowing for structural designs using high-strength Grade 100 concrete reinforcing steels in the city. Through the issuance of the bulletin, the city accepts designs employing the 100,000 psi yield strength of ASTM A1035/A1035M-15 rebar, clearing the way for applications of MMFX high strength ChrmX rebar and efficient high rise construction.
By applying high strength steel reinforcement designs in high rise buildings, designers can solve costly rebar congestion problems and developers can complete construction more quickly, resulting in substantial savings. Using high strength Grade 100 rebar, such as ChrmX 2100 (ASTM A1035), in high rises allows for substantial reduction in steel of up to 40 percent, and reductions in related fabrication and placement costs of up to 60 percent. There are also additional potential efficiencies in construction design, such as narrowing shear walls and columns or thinning mat foundations, resulting in significant savings in costs and time.
“ASTM A1035 is now the only 100 ksi reinforcing steel allowed in any New York structure, the only reinforcement over 80 ksi that can be used in beams and slabs, and the only 100 ksi reinforcement that can be used in Seismic Design Categories A, B and C,” said Tom Russo, MMFX Steel Corporation CEO. “Designing at these higher strengths using this new bulletin and ChrmX (A1035) rebar will result in up-front construction cost savings, as well as increased construction efficiencies and eased logistics, benefiting contractors, developers and city residents.”
Specifically, Buildings Bulletin 2015-036 allows designs up to 100,000 psi yield using ASTM A1035 reinforcement in accordance with ACI 318, as modified by ACI ITG 6R-10 and ICC-ES AC429. The bulletin allows applications of ASTM A1035 Grade 100 reinforcement in longitudinal and transverse members, including slabs and beams, in Seismic Design Categories A, B and C.
With the adoption of Buildings Bulletin 2015-036, New York City joins other major high rise markets such as Miami and Seattle that are already applying high strength rebar designs in high rise towers. The timing of this bulletin is beneficial to design teams and developers with high rise projects planned across New York City. These projects stand to immediately benefit from applications of high strength steel designs as they reach higher and higher to make the most of the city’s precious real estate.
For example, the 111 West 57th Street residential tower being constructed by JDS Construction Group in partnership with Property Markets Group will reach over 1,400 feet into the sky. With a width to height ratio of only 1:23, it will be the narrowest tower in the world.
Other projects currently in planning and construction such as One Vanderbilt (1,514 feet), Nordstrom Tower (1,550 feet), 432 Park Avenue (1,396 feet), and 53 West 53rd (1,250 feet) could have clearly benefitted from high strength designs. The new bulletin provides opportunities for the many towers and skyscrapers in design to realize the advantages of 100 ksi reinforcement and represents an important step forward in the improvement of construction in New York City.