Number of locations
|Mike Squarzini (Co-CEO)|
Peter DiMaggio (Co-CEO)
Wayne Stocks President
Gary Panariello Director
Tom Scarangello Executive Chairman
Number of employees
Thornton Tomasetti (formerly the Thornton-Tomasetti Group, Thornton Tomasetti Engineers, Lev Zetlin & Associates and LZA Technology) is a global, 1,500-plus person scientific and engineering consulting firm.
Thornton Tomasetti has expertise in structural engineering, facade engineering, forensic engineering, structural renovations, construction engineering, Resilience (engineering and construction), sustainable design, applied science, protective design and security, civil engineering and bridge design and rehabilitation. The firm's services are supported by its internal research and development CORE teams, which provides technology-focused expertise, computational simulation and software development and well as artificial intelligence and machine learning.
The firm provides consulting expertise to clients in a variety of industries, including architecture/engineering/construction, insurance and law firms, real estate developers, building owners/operators, defense, life sciences, manufacturing, natural resources and space systems.
1949—Paul Weidlinger opens consultancy: Weidlinger Associates dates back to 1949 with the launch of Paul Weidlinger Consulting Engineers in Washington, D.C. A native of Budapest, Hungary, Paul earned a master’s degree from the ETH Zurich in Zurich. He apprenticed with Le Corbusier in Paris and László Moholy-Nagy in London before coming to the United States in the late 1940s.
1950s—Applied Science division launched: Paul Weidlinger, Dr. Mario Salvadori and Dr. Melvin Baron shared an interest in the dynamic response of structures, which led the firm to create an Applied Science division. The group developed analysis and design procedures to protect structures from the effects of blast loadings. Their methods led to early and continuing use of computers in advanced analysis and design.
1956—Lev Zetlin starts Lev Zetlin Associates: After earning a doctoral degree from New York’s Cornell University, Lev Zetlin decided to start his own company, Lev Zetlin Associates (LZA).
1960—Charlie Thornton joins LZA: Charlie Thornton, who earned master’s and doctoral degrees from New York University and authored a thesis on cable nets, joined Lev Zetlin Associates in 1960. Serving as co-chairman of the firm until 2004, he was involved in the analysis, design and construction of projects worldwide.
1964 -- 1964 New York World’s Fair (Flushing Meadows, New York): Early in his career, Lev Zetlin devised a “double-layer bicycle wheel” roof system. The system combines upper and lower cables with varying tensions that are jacked apart and connected by rigid vertical struts. Connecting cables that have differing natural frequencies minimizes wind-induced fluttering. First developed for the Utica Memorial Auditorium, which was completed in 1960, Lev Zetlin's bicycle wheel system has helped to shape the design of other tensile structures, among them the New York State Pavilion, Madison Square Garden, the Seoul Olympic Gymnastics Arena, Tropicana Field, and the Georgia Dome.
1968—Richard Tomasetti joins LZA: Richard Tomasetti joined Lev Zetlin Associates after working in the aerospace and submarine industries. Tomasetti created Environspace Research and Development, the firm’s first research and development group.
1977—Charlie Thornton and Richard Tomasetti buy LZA from Gable Industries: Charlie Thornton and Richard Tomasetti purchased Lev Zetlin Associates while it was a subsidiary of Gable Industries. It was at this time that the firm began performing some work as Thornton Tomasetti. The firm's name changed officially from the TTG Group to Thornton Tomasetti in 1999.
1980s-1990s—FLEX code introduced: The FLEX code was first developed by Weidlinger in the early 1980s to support Nuclear Test Ban Treaty monitoring. Its name is derived from its primary focus, performing ”fast large explicit’ time-domain dynamic simulations, and from its versatility and speed in modeling unusually large structures. In the early 1990s, the FLEX code was diversified into a family: NLFlex (blast), EMFlex (electromagnetic waves), and PZFlex (sonar and ultrasound). In 1999, SpectralFlex was developed to serve the growing field of medical therapeutics, and in 2002, Weidlinger created the FLEX Template System, for modeling and simulation of structural components of civilian structures subjected to bomb blasts.
2001—World Trade Center collapse (New York, New York): In the 10 months after the September 11 attacks, crews removed more than 1.6 million tons of debris. Thornton Tomasetti staff were the first engineers on the site on September 11, and started work that afternoon.The firm supervised 20 member firms of the Structural Engineers Association of New York and arranged for 24/7 coverage of the site for nine months. The firm assisted in rescue, demolition and clean-up, advising on structural issues that required resolution as part of the recovery effort.
2004—Taipei 101 (Taipei, Taiwan) Completed: The first 21st-century building to become the world’s tallest upon completion, Taipei 101 is, as its name implies, a 101-story tower. Working with engineer of record Evergreen Consulting, Thornton Tomasetti established an efficient steel-based dual structural system and solved wind behavior problems with distinctive double stair-step corners. By 2020, Thornton Tomasetti had designed five of the 20 tallest complete buildings in the world.
2011 – CORE studio founded: CORE studio is the firm's internal research and development group that specializes in application development, computational modeling and artificial intelligence to create efficiencies in the structural design and construction process.
2012—Response to Hurricane Sandy: On October 29, 2012, Hurricane Sandy made landfall near Atlantic City, New Jersey. In response, the firm conducted damage assessment in three states related to structural and architectural integrity, HVAC, electrical, plumbing and fire protection equipment and systems. Included in the investigations were high-rise office and residential facilities, and other retail, rail, aviation and government facilities.
2015—Thornton Tomasetti and Weidlinger merge: Thornton Tomasetti and Weidlinger Associates announced a merger. Weidlinger Associates was a U.S.-based structural engineering firm that designed and rehabilitated buildings, bridges, and infrastructure and provided special services in applied science, forensics, and physical security. The merger created two new entities: CORE Lab - a sister internal group to CORE studio - that focuses on the long-term development of internal methods, capabilities and products to evaluate new business opportunities; and TTWiiN, a technology accelerator and product commercialization platform.
The John Hancock Center is a 100-story, 1,128-foot supertall skyscraper located in Chicago, Illinois. Located in the Magnificent Mile district, its name was changed to 875 North Michigan Avenue on February 12, 2018. Despite this, the building is still colloquially called the John Hancock Center.
Skidmore, Owings & Merrill (SOM) is a global architectural, urban planning and engineering firm. It was founded in Chicago in 1936 by Louis Skidmore and Nathaniel Owings. In 1939, they were joined by engineer John O. Merrill. The firm opened its second office, in New York City, in 1937 and has since expanded all over the world, with offices in San Francisco (1946), Los Angeles, Washington, D.C., London, Hong Kong, Shanghai, Mumbai and Dubai.
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Kohn Pedersen Fox Associates (KPF) is an American architecture firm which provides architecture, interior, programming and master planning services for clients in both the public and private sectors. KPF is one of the largest architecture firms in New York City, where it is headquartered.
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LeMessurier Consultants is a Boston, Massachusetts firm, founded by William LeMessurier in 1961. It provides engineering support services to architects and construction firms. They focus on advanced structural techniques and impacts to construction materials. They are known for their modular construction techniques including the Mah-LeMessurier System for precast concrete in high-rise housing, the Staggered Truss System for high-rise steel structures, and the tuned mass damper used to reduce tall building motion. One of the best known uses of the damper is the John Hancock Tower in Boston. In addition to new construction, they also work with retrofitting buildings and historic preservation.
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Peter DiMaggio is an internationally recognized expert on the design of blast resistant buildings. He was the lead engineer for construction of the U.S. Embassies in Moscow, Berlin and Baghdad.
Simpson Gumpertz & Heger Inc. (SGH) is a privately held ENR 500 engineering firm that designs, investigates, and rehabilitates structures and building enclosures. Their work encompasses commercial, institutional and residential buildings, transportation, water/wastewater, nuclear, science, and defense structure projects throughout the U.S. and over twenty foreign countries. SGH has 600 employees at seven offices in Boston, Chicago, Houston, New York City, San Francisco, Southern California and Washington, D.C.
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Weidlinger Associates, Inc., was a U.S.-based structural engineering firm that designs and rehabilitates buildings, bridges, and infrastructure and provides special services in applied science, forensics, and physical security. Weidlinger's clients include corporations, private clients, institutions, and federal, state and local governments. The firm is headquartered in New York City, with branch offices in Massachusetts, Connecticut, New Jersey, California, New Mexico, and Washington, DC. The firm also conducted business as Weidlinger Associates, Ltd., in Scotland, UK.
Magnusson Klemencic Associates is an American structural and civil engineering consulting firm with its headquarters in Seattle, Washington. The company has completed projects worth more than $99 billion in 48 states and 54 countries. Significant MKA projects through its history include the World Trade Center, the Columbia Center, Aqua, the Doha Convention Center Tower, the Olympic Sculpture Park, and Salesforce Tower.
Guy Nordenson is a structural engineer and professor of structural engineering and architecture at Princeton University School of Architecture. He attended the Massachusetts Institute of Technology, graduating with a Bachelor of Science in Civil Engineering in 1977, followed by a Masters of Science in Structural Engineering and Structural Mechanics from the University of California at Berkeley in 1978. After graduating from UC Berkeley he worked at Forell/Elsesser Engineers in San Francisco (1978-1982) and Weidlinger Associates in New York City (1982–1987), before establishing the New York office of Ove Arup & Partners in 1987 where he was a director until leaving in 1997 to begin his own structural engineering practice, Guy Nordenson and Associates.
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DeSimone Consulting Engineers is a structural engineering firm founded by Vincent J. DeSimone in 1969 in New York City. The firm provides structural engineering services to architects, owners and developers, and performs structural analysis and design for all types of buildings at all project phases. DeSimone also launched a Property Loss Consulting division in 2016. The company has offices in New York City, Miami, San Francisco, New Haven, Las Vegas, Austin, Abu Dhabi, Boston, Chicago, and Medellin. As of 2016, DeSimone has designed over 10,000 projects in 40 states and 45 countries.