Precast concrete helps meet Silver LEED requirements for North Residence Hall.
By Dave Chartrock
In its continuing commitment toward environmentally sustainable design and construction practices, Ball State University’s North Residence Hall project in Muncie, Ind., is using precast concrete to help meet the criteria for the U.S. Green Building Council’s Leadership in Energy and Environmental Design’s (LEED) Silver rating.
“The selection of precast concrete in the form of hollow core slabs helps the North Residence Hall project meet this requirement due to its post-industrial recycled content, thermal qualities and regional manufacturing,” said Tanner Underwood, project architect for Facilities Planning and Management at Ball State University.
Underwood added that previous experience using hollow core slabs in other BSU buildings helped create an even better design for the North Residence Hall, a $35.6 million, 206,000-square-foot project.
Achieving a LEED Silver rating began with the project’s architect, CSO Architects Inc. of Indianapolis. According to Brandon Bogan, LEED AP and project manager for CSO, the firm worked with BSU to define LEED goals and establish a plan to achieve those goals. This process included development of a LEED project checklist to help determine which LEED points could be achieved.
CSO worked with the project’s design team to implement strategies for achieving each point, Bogan added.
The 600-bed residence hall will be erected on a poured concrete spread footings foundation, with steel frame and hollow core precast paneled floors. The exterior will feature Indiana limestone and brick, composite metal panels, curtainwall and aluminum-framed windows.
“Precast concrete was specifically chosen because it reduces structural depth through the utilization of a girder slab system,” Bogan said, “it’s cost effective and it can be installed speedily.”
In general, Bogan added, “to maintain the cost-effectiveness for the project, it was important to maintain a low floor-to-floor height while still achieving a high ceiling in key spaces. This was achieved through the use of the girder slab system, which allowed for a minimal structural depth.”
StresCore Inc. of South Bend, Ind., is the project’s precast concrete engineer, designer and manufacturer of the precast hollow core concrete floor planking.
According to Ken Everett, StresCore’s head of sales and engineering, the project contains about 173,465 square feet of hollow core, including 1,703 pieces of 8-inch-thick floor planking (142,095 square feet) for the residential units and 339 pieces of 10-inch-thick hollow core (31,370 square feet) for a commons unit.
According to Everett, typical 8-inch panels are 4 feet wide and 56 pounds per square foot; 10-inch panels are also 4 feet wide, but are 67 psf. Project spans range from 25 feet to 36 feet for the 10-inch panels and from 21 feet to 30 feet for the 8-inch panels.
“Precast concrete hollow core panels provide an excellent load-carrying capacity, have an excellent fire rating, have low sound transmission, and are good for all-weather construction, an immediate working deck, long spans and low floor depth,” Everett said.
Paul Brumleve, the project’s engineer of record at Lynch, Harrison & Brumleve Inc. in Indianapolis, said that not only was the “girder slab system chosen for its shallow/minimal structural depth, durability and permanence, natural fire resistance and soundproofing properties, but because the repetitiveness of the dormitory room layout worked well with the repetition of the precast and steel members.
The relatively large number of columns associated with the girder slab system due to the relatively limited span of steel ‘D’ beams (hidden within the depth of the precast plank) were easily accommodated within the room layout of a dormitory,” he added. “The use of fly ash in the production of the precast plank and the high percentage of recycled material in the structural steel helped with the LEED rating.”
Each project team member is involved in helping to achieve the Silver LEED rating. In fact, weekly meetings are held to discuss the LEED process, according to Zach Jones, a project manager with Sheil Sexton Co., the project’s Indianapolis-based general contractor.
Bogan added that “overall, precast will contribute to the success of the project as an ‘unsung hero,’ because it is a key portion of the structural system and the speed at which it can be installed will allow for a shortened construction schedule.”
Construction began in June 2008. Plans call for the North Residence Hall to be substantially completed by May 2010 and opened for the fall semester in August 2010.
David S. Chartock is a freelance writer based in New York City. He writes for both trade and national business publications. He can be reached at [email protected].