An engineer once asked me if I could help him with his diet, because “you’re sure good at helping buoldings use weight

For Immediate Release

November 10, 2006

Shed Excess Weight from your Building and Budget

By Paul Clark, Jr., Vice President, Metal Stud Crete

An engineer once asked me if I could help him with his diet because, “you’re sure good at helping buildings lose weight.” He meant buildings like the new Munger Research Center at the Huntington Library, where Metal Stud Crete helped cut over 1000 tons of dead load from a structure with a 30,000 sq.ft. footprint. And by using Metal Stud Crete the engineers also significantly reduced the seismic bracing necessary… just 20 miles from the San Andreas Fault.

Everyone in design and construction knows the advantages of architectural precast concrete as a cladding material: durability, speed of construction, design versatility and high-quality architectural finishes. We also know its big drawback: it’s heavy.

Metal Stud Crete eliminates the weight problem without trading off any advantages. The Metal Stud Crete system, a proprietary thin-wall precast concrete system, marries 2.5 in thick faces of architectural precast concrete to light-gage steel stud framing. Metal Stud Crete’s shear transfer strips, fabricated from galvanized steel, are screwed onto the steel studs and their Y-shaped flanges are embedded into the wet concrete to produce an economical and reliable precast panel. Structural testing and use on hundreds of buildings have verified that the bond of the concrete to the metal framing assembly through the Metal Stud Crete shear connectors achieves full composite action. The system is approved under International Code Council (ICC) Evaluation Service Report ER-5446.

This marriage of concrete and steel is a happy one because it dramatically reduces total panel weight by as much as 70%. This translates into significantly reduced dead load of the exterior skin, yielding substantial savings in superstructure, footing and foundation. There are other advantages: the practical panel size can be much larger, so structures can be enclosed on an accelerated schedule with smaller, lighter equipment.

The integrated steel studs provide a substrate for interior finishes and cavities for utilities and insulation. This saves “energy-space” since insulation can be installed in space that would otherwise be occupied by concrete. It also increases net useable floor area in a building by eliminating the four to six inches that might otherwise be required for furring.

FOR POSTERITY & PROSPERITY

The advantages of Metal Stud Crete were striking in the case of the Munger Research Center. The Huntington Library, in San Marino, California, owns one of the world’s premiere collections of rare books and manuscripts including priceless treasures like a Gutenberg Bible, Shakespeare's quartos and folios, and the papers of the American Founding Fathers. The Huntington’s existing facilities were taxed far beyond capacity. “We were desperate for space,” explains Avery Director of the Library David Ziedberg. “We were already storing some of the collection off the grounds.”

When funding became available to add 90,000 sq ft, roughly doubling the library’s space, the Huntington had a major wish-list of uses including laboratories for document conservation, a reading room for scholars, administrative space, and most importantly, environmentally-controlled safe storage for the collection.

Together with design-build contractor Earl Corporation of Irwindale, CA, they established the following goals:

· Reinterpret the neo-classical architecture style of the Huntington’s original buildings,

· Complete the building within a limited budget and tight schedule, and

· Create a facility that would protect its fragile treasures against the natural disasters and the ravages of time.

Early in the project, precast concrete was identified as an appropriate cladding. It could be finished to match the plaster and natural stone used on existing campus buildings. Precasting panels off site would accelerate construction. And the durability of precast made it suitable for a projected 100-year service life. However, concerns about weight loomed even larger than usual because of two special design requirements:

Since the Huntington is located in one of the most seismically active zones of North America, the building was designed as an essential facility, exceeding code requirements by 50% to assure that the collection remained protected in the event of a major earthquake. Designing for the mass of heavy concrete walls would have added to the expense of beefing up the steel structure and bracing.

Second, the extraordinary level of climate control required for document preservation made it necessary to create a nearly airtight exterior envelope. The weight of conventional precast limits the practical size of panels; this creates a large number of joints where air or moisture could infiltrate. Earl Corporation wanted to use larger panels to minimize the number of joints that had to be sealed.

WEIGHT LOSS MADE EASY

With these concerns in mind, they looked to Metal Stud Crete. Our system offered all the functional and aesthetic benefits of precast, and the reduced weight helped make the project feasible. According to structural engineer Jackson Wu of Johnson & Nielsen Associates, “We would have needed an average 8 in of conventional concrete. By using Metal Stud Crete precast panels, we reduced the weight about 65%.”

Bert England, the project designer at Earl Corporation, says the Metal Stud Crete system “cut six inches from the wall thickness” by eliminating the need for furring its interior surface. Multiplying this by the perimeter of the building, Metal Stud Crete trimmed approximately 800 sq ft from the plans, further reducing project costs.

BIG IS BEAUTIFUL

The larger panel size made possible by Metal Stud Crete also reduced the quantity of panel joints by approximately 40% and made it possible to locate joints where they could be concealed by architectural elements: vertical joints occur at changes in wall plane and horizontal joints are behind moldings. With environmental control a key design objective, the entire interior of the precast panels was sprayed with closed-cell foam to achieve a moisture barrier and thermal break and minimize air intrusion. Temperature can be maintained in the building to within a tolerance of ±one degree.

These benefits add up, and Earl Corporation estimates that using Metal Stud Crete slashed 10-15% off the cost of the building’s structure and enclosure.

Panels were produced offsite by Coreslab Structures (L.A.) Inc. simultaneously with the erection of the building’s steel structure, and installation proceeded as the steel was erected. The light weight of thin-shell precast made it practical to cast, transport and erect panels up to 16 ft tall x 40 ft long. Bob Konoske, vice president and general manager of Coreslab, comments, “It was very aggressive to make precast panels this large. Conventional precast concrete would have been much heavier. Practically, we could not have made conventional panels this big.”

One of the things I love about challenging projects is that they bring out the creativity of the designers and builders, and we learn new things about our own product. For instance, Earl Corporation’s designer took advantage of those large panel sizes to create a visual scale not possible with small, quarried blocks of natural stone. With almost all joints between panels concealed, the result is a virtually monolithic appearance, as if the entire building had been sculpted from a single mass of limestone.

To achieve the period look harmonizing with the campus’s original buildings, entrances and windows have 30 inch recesses that create dramatic shadows. This was the first time Metal Stud Crete had ever been used to create such deep returns. Again, challenge yielded innovation, this time by Coreslab. Coreslab cast the returns in a downcast position, and then the panels were rotated so the faces could also be downcast. With tight quality control, no pour lines or joints are visible at the transition between the two surfaces. Altogether, 325 precast components were cast and assembled to create a total of 146 building panels.

The huge panels had to be shipped on a slanted easel at a 35-degree angle to stay under highway height and width limitations. The panels’ large size caused some concerns about fragility, but they made the 80 mile journey to the construction site without cracking, a very convincing test of durability.

The precast panels were erected without mishap in less than two months, allowing the complex HVAC systems and laboratory equipment to be installed on schedule. The Munger Research Center was completed on time and within budget, with the exterior walls accounting for just $1,500,000 of the project’s $20,000,000 construction cost.

NEW HORIZONS

Unusual challenges like this highlight the possibilities of an innovative product. This doesn’t mean, however, that Metal Stud Crete is only for special situations. Metal Stud Crete is a proven, cost-effective solution that’s been used on over 1.5 million square feet of both load-bearing walls and curtain walls. For example, it was used at Boise State University’s indoor football practice facility in Boise, ID to extend conventional tilt-up walls to an astounding 120 ft. height, and is currently being used to clad the 12-story luxury Domus condominium in Philadelphia, PA. Metal Stud Crete has also been attracting attention from people interested in environmentally sustainable construction because it uses less material and allows superior insulation. It’s a product that’s changing the conventional wisdom of what can be done with precast, and new uses for Metal Stud Crete are being found every day.

For More Information, visit www.metalstudcrete.com.

Editorial Contact:

Michael Chusid, 818-774-0003, michael@chusid.com

Text and high resolution images may be downloaded at www.chusid.com/PR.htm or by clicking on images below.

PHOTOS

Credit Photos: Courtesy Metal Stud Crete

FACADE: The Munger Research Center offers a contemporary reinterpretation of the neoclassical architectural detailing used throughout the Huntington Library and Gardens. Thin-shell precast concrete panels were used for exterior walls. (JPEG 1,618 KB)

FABRICATION: Panels used the Metal Stud Crete shear transfer strip to create a composite with a 2-1/2 inch thick concrete face joined to cold-formed metal stud framing. (JPEG – 1,754 KB)

FABRICATION CLOSEUP – To make the thin-shell concrete panels, Y-shaped shear transfer strips are used to create composite action between the cold-formed steel studs and the concrete faces. Welded-wire mesh is used to reinforce the concrete. (JPEG – 1,971 KB)

TRANSPORTATION: Because the thin-shell panels are lightweight, they could be fabricated in sizes up to 16 feet high by 40 feet long. Special handling procedures were required to transport the very large panels to the job site. (JPEG – 880 KB)

ERECTION: 30 inch deep returns were fabricated in the panels to create the illusion that very thick traditional masonry construction had been utilized. The large panel sizes reduced the number of joints between panels to decrease air infiltration and improve energy efficiency. (JPEG – 1,084 KB)

EXTERIOR AT DUSK (JPEG – 5,520 KB)

This image is also available in a 28 MB TIF file.

CLOSEUP OF FACADE (JPEG – 1,704 KB)

DOMUS CONDOMINIUM: While originally designed with a brick cladding, the Domus condominium in Philadelphia, PA was changed to a Metal Stud Crete wall so the project could be completed sooner. The designer was able to use brick form liners and colored concrete to match the visual style he wanted for the building. (JPEG – 364 KB)

BOISE STATE UNIVERSITY: Metal Stud Crete was used to extend the walls of Boise State University’s indoor football practice facility to an astounding 120 ft. height. A partial height wall was built with conventional tilt-up construction with full-thickness concrete. Metal Stud Crete panels were used for the upper wall because of their lighter weight. (JPEG – 1,460 KB)

Additional images are available upon request.