Marriott Marquis Washington, D.C.



The Marriott Marquis is a 15-story hotel with 1,224 guest rooms surrounding an atrium lobby, ground-floor retail and restaurants, a 5,200 square-foot outdoor event terrace and a two-story fitness center. Seven below-grade levels house 105,000 square feet of event space, including three double-height ballrooms; mechanical and back-of-house areas; and parking for 400 cars. The hotel also integrates a renovated historic building. Fitting the hotel’s 1.25 million square-foot program on a tight 100,000-square-foot site and within Washington’s strict height limits required the use of top-down construction and innovative structural design.

Top-Down Construction

While the superstructure consists of standard flat-plate concrete, conventional structural systems stopped at grade. Site constraints ruled out standard bracing methods for the 100-foot-deep excavation, making top-down construction necessary. After installation of a slurry wall, composite steel interior columns and drilled-shaft foundations, the highest basement slab was poured. Then excavation for the next slab down progressed as a mining operation and the steel columns were encased in high-strength concrete. This allowed the slabs to act as diaphragms to brace the slurry wall. Superstructure construction began while basement levels were still being excavated.

Innovative Steel Design

The below-grade ballrooms required creative structural design to control settlement of the 15-story tower above. Eight massive steel-plate transfer girders span above the 30,000-square-foot grand ballroom and support the superstructure’s columns. Two of these girders were preloaded before tower construction began, straightening an initial camber of 4.5 inches. As construction progressed – loading the girders with the weight of the structure above – the preloading was incrementally relieved. At completion, the trusses were straight, keeping the structure level.

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Our structural engineers have experience in the full spectrum of delivery methods, from traditional design-bid-build, to fast-track, construction manager-at-risk (CMR), design-build, Integrated Project Delivery (IPD), Lean Project Delivery (LPD) and hybrids of all of these.

Our collaborative approach is well suited to newer delivery methods that are designed to foster greater cooperation, and we strategically apply the benefits and best practices of these methods to enhance traditional design-bid-build projects.