Erection and Installation

Petty talked about what made the Perot Museum project particularly challenging for his company's precasters. “On the production side it was the number of non-flat panels,” he said, “while on the erection side the most difficult part was hanging all of the under-structure panels and those panels that leaned away from the building.”

To hang the panels, the precasters recommended locations for gravity-load embeds that would be likely to work in many of the building's perimeter conditions. Working alongside the structural steel detailer, the project team found a zone for the embeds that would work on every floor. Then the precasters labeled the panels with their module and with the panel number on each corner.

At the project site, the panels were held in a staging area set by general contractor Balfour Beatty that could hold up to five trailers near a tower crane. Three crews worked on separate parts of the building to set the panels, using nonstandard methods developed specifically for the project.

In spite of the BIM modeling and detailed planning, installation moved slowly. Surveying was required to ensure that each panel was set properly, which allowed the installation of only about four to six panels per day—and sometimes fewer. The installation of the building skin was substantially complete by the end of 2011.

A Green Façade System

In addition to giving the museum a striking aesthetic, precast concrete was chosen for its sustainability. The museum is pursuing Green Globes, LEED, and Sustainable Sites Initiative certifications. Despite his commitment to sustainability, Mayne was quoted by the San Francisco Chronicle in 2007 as saying, with regard to his design for that city's Federal Building, “I have no interest in being a 'green architect'…I find the term ridiculous.”

Of that building's design, Mayne told the Chronicle, “I'm interested in skin as a sculptural idea”—an idea he and his colleagues at Morphosis would explore further through the design of a Parisian tower, of which he said, “We're writing the script for the performance of the façade…The aesthetics and the performance are inseparable.”

Mayne achieves this goal anew with his Perot Museum design by way of the use of precast concrete, which not only reflects the building's natural surroundings but also acts as an insulating and temperature-regulating material due to its thermal mass. That is, the museum's precast concrete exterior will absorb and release heat as outside temperatures rise and fall. By naturally regulating to a large degree the building's interior temperature, the museum's concrete exterior will take some of the burden off the facility's HVAC system, thereby contributing to the facility's energy efficiency.

“The thermal mass of the precast concrete reduces the daily temperature swings on the building by absorbing and releasing heat slowly, shifting air conditioning and heating loads to allow smaller, more efficient heating, ventilating, and air-conditioning systems,” says Perot Museum spokesperson Becky Mayad. “A smaller HVAC system also requires significantly less power to operate and reduces the demand on the overall power consumption for the building.”

The Perot Museum also notes that the use of precast helps achieve significant reductions in heating and cooling costs and contributes to an overall energy performance that exceeds Texas Building Energy Code by 14 percent, based on a building energy analysis by the project team. According to its State Energy Conservation Office (SECO), the Texas energy code seeks to achieve 90 percent compliance with the recently adopted 2009 International Energy Conservation Code (IECC) by 2017. “In addition to exceeding the Texas Energy Code by 14 percent, precast concrete contributes to green building practices which have both a direct and indirect effect on energy use and cost savings,” says Mayad.

Mayad explained, for example, that, “The sand, aggregate, water, and cement used in the panels were sourced locally and the panels were poured within 500 miles of the building site,” adding, “Because precast concrete is factory-made, there is little waste created in the plant and it reduces construction waste and debris on site.” With these and other green advantages to the building technique, says Mayad, “The use of precast concrete had a direct contribution to the reduction of construction waste on site due to the inherent qualities of the materials used, casting process, and erection process.”

In the case of the Perot Museum, “The panels did not receive any post finishing such as acid etching or sandblasting,” nor did they “need to be sealed or painted,” says Mayad. Once it's been fabricated, precast concrete can be installed fairly quickly, which cuts down on construction costs. Its durability means it requires little in the way of maintenance, she adds.