Magazine article Corrections Forum

Digging into the Best of Modular Steel & Precast Concrete Construction

Magazine article Corrections Forum

Digging into the Best of Modular Steel & Precast Concrete Construction

Article excerpt

STEEL AND CONCRETE cells each have their differences and advantages, though it is difficult to compare them directly. Comparing per cell cost, for instance, may not give an accurate picture because steel construction may require less site work because cells are lighter. On the other hand, concrete cells are load bearing and may not require the beams and supports that steel does.

A head-to-head comparison must be done thoroughly, early in the process before proceeding to the design phase, and one must review site costs, labor pools, how long the CM or GC must be involved and other factors unique to the jurisdiction.

But while the differences must be examined, one thing is for sure: Modular construction in almost any form has been widely proven to reduce cost.

Modular construction in a precertified factory positively guards against workmanship flaws and change orders, keeping costs down and moving the project along. In addition, prefabrication can start off-site before or during site prep, shaving more time. Weather delays due to cold, heat or wetness are also abbreviated. One industry veteran says that any modular construction beats conventional construction by "40 percent to 50 percent." And lack of labor pools for masons or steel workers in a remote area are not a concern. Both precast concrete cells and precast steel cells are also stronger than traditional concrete masonry block, which makes for better security.

While precast and prefabricated construction is being used extensively for prison, jail and detention centers, especially larger projects, what are some of the strengths and possible drawbacks to using steel or concrete?

Testing Their Mettle

While modular steel cells had their debut in the 1970s, many firms jumped in and out of the corrections arena, notes Michael "Mickey" Rosenberg, a sales consultant and industry veteran with Meta-Lite, Inc., a central New Jersey maker of modular steel cells, among other types of structures. (They will be supplying custom railings for Jersey Shore communities hit by Superstorm Sandy.) Some companies didn't meet the stringent criteria demanded by the prison industry, he notes, and bowed out of the business.

While Rosenberg estimates there are some 30 thousand to 40 thousand modular steel cells in use, and these have withstood the test of time, concrete has found the most success in this industry, perhaps because "architects are used to designing with precast."

In the 1990s, he furthers, steel had a disadvantage. Not only general contractors couldn't grasp the savings - in time and size of footings," he says, "because they were designing the footings for CMU block" and thus oversizing them. He adds that steel also has a LEED impact for sustainable buildings because it is made of 90% recycled material, it is extremely durable and it is easier to insulate. "Back then lifecyle didn't mean anything."

Today it does. "Private operators now realize bigger costs come on the energy side," Rosenberg points out. Sustainability and maintenance are a huge part of the complete operational budget of a facility. Coated with either polyurea or a powder coat, "Steel cells hold their finish for many, many years - cells in place since the '90s have never had to be refinished," he says.

Today, if you put a bid out and design the job specifically for steel, Rosenberg states, "Modular steel cells have competed extremely well and sometimes beat precast."

Speed of construction

Speed is our greatest advantage, says Ray Handte, vice president and COO with SteelCell of North America, in Baldwin, Georgia. On the assembly line, they can be made extremely fast, he says, and the low weight helps in other construction costs. "Concrete requires heavier equipment (a crane compared with a boom truck), special shipping and a specialized site," he notes.

Rosenberg adds that because of the substantially lighter weight and the ease in handling - offloading, stacking and building - and the reduced footings, they can be constructed 10% to 20% faster than precast units. …

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