PROJECT OVERVIEW

During a multi-year assessment of the circa-1974 museum, the owner identified several issues to be addressed. Most significantly, the precast panels on the unique circular exterior were no longer viable, as they had compromised lateral attachments at many locations. And because the original structure had been built in a fast-tracked manner, there were numerous imperfections in its original construction.

The initial project focused solely on the exterior 44,400 square feet of precast recladding with a future contract to be awarded for the full revitalization of the interior (60,000 square feet). The corrections also included the installation of new waterproofing and insulation layers between the precast walls and existing structure, which in turn enlarged the façade by 3 inches in radius.

INNOVATIVE PRECAST SOLUTIONS

The team incorporated the use of laser scans and data-point modeling, as well as traditional surveying methods, to determine the existing conditions of the underlying structure. The precaster, designed and implemented an innovative system for hanging the new panels that would accommodate the existing conditions, meet blast-load requirements, while also dealing with minimal access behind the panels.

In order to meet the historical preservation requirements to match the appearance of the original panels from when the museum was first constructed, Millennium Pink granite was sourced from the quarry that originally provided the stone. No area in the panel could be larger than a quarter without exposed aggregate, and there were limits on the amount of naturally occurring black and white rocks that could be exposed.

Following the precaster’s internal QC inspections at its manufacturing facility, the client performed an additional 30-point inspection of the panels upon their arrival at the site. The owner’s representative, general contractor, and architect individually inspected every panel from 10 feet. Procore was used to track and document inspections and the resolution of any concerns. By project’s end, the team had erected 673 pieces wall panels, along with numerous blended plugs and filler pieces wherever access holes were needed to complete connections.

All the precast panel restoration work was performed as the museum remained open. The challenging, and often complex job, was completed on time and on budget, bringing the iconic museum back to its original grandeur and provided it with a significantly longer service life.

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PCI-Certified Precast Concrete Producer:

Architect:

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Key Project Attributes

• There were extremely tight aesthetic requirements at the Museum site. Given its central location on the National Mall and historical significance, external approving parties such as the U.S. Commission of Fine Arts Commission of Fine Arts and the Smithsonian’s Office of Planning, Design and Construction (OPDC) were heavily involved in project oversight.

• While the building expanded in diameter to facilitate improvements to the waterproofing systems and additional insulation, it maintained the same relative panel sizes (90 equal panels) and joint layouts around the building. This was done while also updating the design to current codes, including blast design requirements.
• The entirety of the project was modeled in BIM using digital scans of the underlying structure. The digital scans were “backchecked” with more traditional surveying techniques to ensure that they properly represented the underlying structure. Incorporating the digital scan technology, still in its infancy, into the BIM model in a functional format that enabled the team to make design adjustments was a significant challenge. To visually communicate the design to the client, the precaster created full scale mockups of eight panels, which remained on site until the project was completed.

Project/Precast Scope

• 60,000 square feet of exhibition space; 44,400 square feet of precast concrete panels
• 673 pieces of precast wall panels; 230 plug and filler pieces
• The new precast concrete cladding was thinner than the cladding on the existing building to account for the building’s new insulation and water barriers and included
• The use of precast afforded greater control over the process and enabled the owner to maintain museum operations with minimal noise impact