Fast—Track Inside—Out Construction
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| A 3/8-inch ribbed concrete panel with a light sandblast finish was chosen for the façade of MCG’s Interdisciplinary Research Building . This subtle pattern creates an interesting play of light and shadow throughout the day. |
When the Medical College of Georgia (MCG) in Augusta charged its design team to build a high-performance research laboratory building with an extremely tight move-in date only 14 months away, traditional ways of erecting the structure had to be discarded. The design team’s answer to MCG’s challenge was the creation of a novel process for erecting precast that involved an innovative "inside-out" method of construction in which the building envelope was installed first and the precast was installed last.
The design and construction of MCG’s Interdisciplinary Research Building, Phase II (IRB) is a testament to teamwork and dedication. As a core component of MCG’s research campus, the $27.3 million, 94,000-square-foot IRB houses specialty labs ranging from tissue culture and bacterial culture suites to clean rooms, bioinformatics and radio-isotope suites. It provides MCG with the ability to respond to the changing field of scientific research for many years to come and will also help to stimulate the local economy by providing incubator space for growing and newly formed business ventures.
Why Precast?
Precast was selected as the material of choice because of the aesthetic it would provide, its durability (the building was designed with a lifespan of 50 years), its schedule efficiency and its overall cost effectiveness. The surrounding campus architecture, which ranges from brick and stucco to metal paneling, is complemented by the precast. A 3/8-inch ribbed concrete panel with a light sandblast finish was chosen for the façade.
The Challenge: High Performance in 14 Months
The challenge here was twofold: not only did the project have to be designed and constructed within 14 months, but the nature of the facility required a controlled environment and tight building envelope to prevent contamination of the research inside. Negative pressure zones in the laboratory areas can create a higher thermal/moisture drive through the exterior walls, and a true precast veneer did not lend itself to the high-performance requirements of the building envelope. A typical alternative in these situations is an 8-inch concrete masonry unit (CMU) backup wall system, but this method called for a longer construction schedule than was available. The solution, a process the design team would come to call "inside-out" construction, would provide for a better performing facility and would also allow the interior construction to progress concurrently with the design and installation of the concrete panels, rather than waiting for the finished exterior.
Inside-Out Construction
The solution was straightforward. It was determined that a high-performance barrier had to serve as the exterior envelope. Installed behind the precast, the membrane brought the precast panels out of the critical path for building envelope construction. It could be installed faster, allowing the building to dry more rapidly, thereby facilitating interior construction. The membrane also performs better than a typical CMU backup system – a perfect fit for the special requirements of the building.
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| Precast was selected as the material of choice because of the aesthetic it would provide, its durability (the building was designed with a lifespan of 50 years), its schedule efficiency and its overall cost effectiveness. |
This construction process also brought its unique challenges. One challenge was the need to protect the high-performance barrier during the installation of the precast panels. Typical welding procedures would damage this critical element, so the solution was to weld only at the bottom row of the concrete panels. From there on up, the panels were stacked and attached with mechanical fasteners, allowing most of the weight to sit on the bottom row. This process influenced the design of the individual panels. An interlocking design was needed, so a male-female connect was created, resulting in inverted "T" and "I" shaped precast panels. This interlocking pattern led to a stronger veneer, and an easily recognizable "lighting bolt" pattern arose from the design process. This pattern facilitated installation because of its strong visual clues.
Another unique challenge was the location of all connections between the high- performance barrier and the panels. The connections, accessible only from the outside of the panels, demanded a solution that enabled the installers to reach behind the panels to fasten the connections. In order to allow for this, the design increased the clear space between the concrete precast and the barrier to twice the typical size. Instead of a 2-inch space, the clear space for this facility is 4 inches. Likening the installation process to "changing the oil on a Honda," the design team took extra steps to assure the erector team that they could successfully complete the installation of the fasteners – to the point that they conducted in-house studies and created rough mock-ups that could be tested.
The Result
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DESIGN TEAM Owner: Medical College of Georgia |
The unique challenge of this project led to opportunities and advancements in the design and installation of the precast with success solely achieved through a concerted, team-oriented effort among the architect, contractor, fabricator and erector. The novel approach resulted in a four-week reduction of the construction schedule: three weeks were saved by separating the panels from the critical path and allowing the panels to be installed as a veneer material, and one week was saved through the management of the fabrication and installation of the precast materials.
In the long run, the durability and permanence of the precast concrete panels will lead to an overall reduction in life-cycle costs. The design was, in effect, influenced by the nature of precast itself and stands as a tribute to the properties of concrete and, of course, the persistence of a hardworking and dedicated team.
Howard Wertheimer, AIA , LEED AP, (hwertheimer@lasarchitect.com) and R. Grant Stout, Jr., (gstout@lasarchitect.com) are principal and project architect, respectively, with Lord, Aeck & Sargent, an architectural firm that designs and renovates educational buildings from K-12 private schools to multi-use facilities and science research laboratories on college and university campuses.