Although most segments of the construction industry are in a downturn, there remains some activity in the education sector, although this varies by region. Some contractors report higher volumes of school construction than last year, while others say its region saw little to no growth. Many of the projects moving forward in 2011 have used structural concrete because owners sought sustainability, low maintenance and operating costs, fair prices, natural event resistance, and speedy construction. Contractors and suppliers report reasons why schools are being built include:
- Older units no longer serve current educational needs. For instance, many school systems didn't have money to build in the past even though student enrollments increased rapidly, so they used inexpensive modular classrooms. Now these are worn out and must be replaced.
- School populations are increasing, especially at the college level. This is partly due to students opting to pursue advanced degrees rather than enter a distressed job market where success at finding a job is diminished.
- Sustainable, energy-efficient construction is in demand for schools.
But in a recent interview in School Construction News, Joe Jouvenal with McCarthy Building Construction's Southeast Division notes, "Though there are more projects this year than last—there is generally a lack of projects that can be financed right now." He explains this has led to extreme competition resulting in general contractors that specialize in school construction "going against people who are not as qualified, and who are being very aggressive with price at the expense of delivering quality."
School construction isn't a steady market. Ron Eldridge, operations manager for the concrete division of Sundt Construction, Tempe, Ariz., says in 2009 school construction accounted for 35% of the revenue in its concrete division—40% at the university level and 60% for high school construction. The overall percentage dropped to 3% in 2010, while this year, projected revenues will reach 40% of revenues with most projects being university research facilities. Most of these projects feature architectural concrete, polished concrete floors, and bonded toppings.
Pushing for energy efficiency
In that same School Construciton News article, Larry Bacher, vice president for higher education at Gilbane Building Co., Providence, R.I., explains that sustainable construction today is no longer a trend, but a given. "Almost everybody expects that the project is going to be done LEED Silver."
Eldridge thinks this emphasis on sustainability is one of the driving factors pushing schools toward concrete construction. Clients choose to leave concrete walls exposed, reducing the need for other building materials, and making them more aesthetically interesting by adding architectural concrete effects. Diamond polished floors eliminate the need for carpet, vinyl, or wood finished treatments. "Diamond polishing is less expensive than doing terrazzo finishes too," he adds.
Brad Nesset, the vice president for sales for Composite Technologies Co., Boone, Iowa, says many school projects focus on improving the thermal efficiency of the building. Concrete wall construction is ideal for improving thermal efficiency because it eliminates air movement through a building's walls. Optimal thermal efficiency is achieved as long as other materials or building features, such windows and doors, are sealed properly.
Nesset's company manufactures and distributes Thermomass, a system of spacer and insulation panels for sandwich panels with insulation centered in the concrete walls, making it possible to use the concrete surfaces on both sides as finished surfaces. This process often is used to produce insulated tilt-up panels.
Glen Doncaster, president of Citadel Contractors, Apex, N.C., is busy building schools using tilt-up concrete methods. Doncaster says Citadel's tilt-up projects are very cost efficient and focus on making the buildings comfortable and inviting without spending too much on details. Citadel's current school construction project is 38,000 square feet. "It's hard to get money to build a school right now and to operate it, so [school districts] are concerned about minimizing operating costs," Nesset says. Many of Thermomass's current customers are building elementary and high schools.
Constructing university research facilities
Currently there are a number of research building projects under construction at universities around the U.S. Bacher, in School Construction News, noted that Gilbane is tracking more than $2 billion in teaching and research laboratories. According to Dane Rankin, an associate director at Skidmore, Owings & Merrill (SOM), Chicago, research facilities require reduced vibration. Research building floors often pose special challenges because they must reduce floor vibrations generated by a host of causes, including air handling equipment and even passing traffic. This requirement stems from the sensitive nature of the conducted research projects. Often these projects focus on specialized research—genome experiments, for instance, which are so sensitive, any vibration can affect the results.
This type of construction poses challenges for contractors because thickened concrete is the only practical way to achieve this specification, and a more robust building structure is needed. When constructing a 20-inch-thick floor, larger, more complex forming systems are needed, columns are bigger, and massive amounts of steel reinforcing are installed. The additional manpower, equipment, testing, and placement time also complicates the project.
One educational project featuring this type of construction is at the University of North Carolina, Chapel Hill. In 2004 SOM, signed a contract to design the Genomic Science Building. It took the past seven years to secure the funding package for the project, but today the construction of the structural concrete building is underway and making special use of concrete.
Before bidding, the owner built a large "referee" panel, the construction of which was supervised by an outside consultant. The integrally colored panel used 7000-psi compressive strength concrete with slag as a supplementary cementitious material. Each bidder had to submit documents stating they had viewed the panel and could build to the required level of quality. As the winning bidder, Morley Construction, Santa Monica, Calif., was required to build a mock-up panel to demonstrate its work.
The 200,000-square-foot research building will feature 19-inch-thick, highly reinforced, reasonably flat and level, thickened concrete floor slabs. To achieve flatness, engineers designed camber into the slabs because of the long spans and cantilevers. Flat-plate construction is used to reduce the total floor-to-floor height compared to structural steel construction, saving on the overall building cost. Slab edges are cantilevered.
Peter Ruggiero, a SOM director, says the architectural concrete walls are exposed on both sides to lessen the need for other materials and to reduce labor costs. The walls also help achieve LEED certification points. Given the temperature fluctuations in the region, the building will take advantage of the concrete's thermal mass to help mitigate temperature swings. Rankin says that Morley has the option to use a self-consolidating concrete (SCC) mix for wall placements with congested reinforcement, but they must color match the other concrete walls. Some of the walls are sandwich panels with center insulation to provide higher R-values. All floor surfaces are diamond polished to provide a pleasing aesthetic and to eliminate the need for other finish surface products.
A second recent research facility project built by Morley is the Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Research at the University of Southern California (USC). Morley vice president Chris Forster says the building's design provided maximum open floor space with minimal column and wall interruptions. A significant challenge involved the construction of a 30-foot 6-inch span floor slab on the building's third floor that overhangs the front entry to the building. Because the floors were 16 to 19 inches thick and due to the region's seismic building code requirements, these slabs were heavily reinforced. The reinforcing requirements for shear walls also was so extreme and complicated, Morley completed a mock-up demonstrating its ability to install the reinforcing steel before construction officially began.
Forster notes an interesting building feature is an exterior wall made entirely of glass held in position by cables running between concrete anchors from the base of the building to the roof.? The 93,000-square-foot building used 11,562 cubic yards of concrete and 3.55 million pounds of reinforcing steel, averaging 39.39 pounds per square foot.
What schools want
Most school projects require contractors with expertise who must sell owners on its skills and become a partner in the decision-making process regarding construction details. It's not just a matter of having the low bid. School budgets are tighter than ever and school administrators are focusing on building thermal efficiency, with a desire to lower operating costs. At the same time, school boards want to incorporate sustainability into new buildings and also expect a long service life. School districts are discovering concrete is an ideal construction material to achieve these goals.