healthcare_durhamThe University of Nebraska Medical Center (UNMC) desired to expand their medical research facilities and consolidate their high-end researchers into one building. Anchoring the new research mall, the Durham Research Center in Omaha, Nebraska fulfilled the wishes of UNMC. The Durham Research Center enables UNMC to enhance its numerous areas of research, including cancer, cardiovascular diseases, neurosciences, transplantation biology, genetics and eye research.

This world-class facility is highly functional with exceptional aesthetics. The 289,000 sf structure has nine stories and houses 116 state-of the-art research laboratories, a 319-seat auditorium, conference rooms, and classrooms. As the western edge of the property curves, the building perimeter follows suit. The traditional brick façade gives way to a modern curved curtainwall, unifying internal functionality with external artwork. The northwest corner showcases an exposed intricate stair tower the full height of the structure.

The structural framing system is wide-modular pan and joist construction. The wide-modular joists are 13 inches wide by 20½ inches deep, spaced at 5 feet 6 inches on center, spanning 25 feet and 30 feet lengths. They are supported on 36-by-20½ inch beams, which span 22 feet. This is the most economical framing system for supporting the 125 pounds per square (psf) design live load. The pan voids allow for easier placement of plumbing and electrical components, as well as the void layout fits easily into the modular lab units.

The facility resides in the side of a hill, creating a 40 foot unbalanced soil condition. The site required a mechanical stabilized earth (MSE) system due to the high unbalanced soil loads. The upper 17 feet of the unbalanced earth pressure and the remaining lateral forces are resisted by cast-in-place concrete shear walls with frame interaction. The typical floor to floor heights are 16 feet, supported on 30 inch diameter interior columns and 24-by-24 inch exterior columns. The shear walls and columns used a concrete strength of 5,000 pounds per square inch (psi), while the floors concrete strength was a standard 4,000 psi mix design. An estimated 23,000 cubic yards of concrete were required for the structure – enough concrete to pave approximately 25 football fields.

The project was completed by the 24 month construction timeline and within the prescribed budget. Except for $2.5 million from the Federal government, the entire $77 million budget was generated by private funds.

Concrete - The Better Outcome

The structural engineer of record, Michael Kuhse, said, “Concrete is the superior framing material for buildings of this use.” Cast-in-place concrete has natural characteristics and stiffness advantages for vibration reduction, which is a great concern for research facilities. Preliminarily, the concrete design was more expensive than steel. After the steel design sizes were increased to account for vibration control, concrete became more competitive in pricing.

Concrete also has the strength to support the heavy laboratory loads with an economical floor depth, while accommodating the complex floor layout to allow for a more “flowable” design. The intricate stairwell in the northwest corner, dictated by the architect, lent itself to using concrete. This prominent architectural feature called for cast-in-place exposed colored concrete to make its statement.

Credits

Owner:
University of Nebraska Medical Center, Omaha, Nebraska

Architect:
HDR, Inc., Omaha, Nebraska 

Structural Engineer:
HDR, Inc., Omaha, Nebraska

General Contractor:
Hawkins Construction, Omaha, Nebraska

Concrete Supplier:
Ready Mixed Concrete Company, Omaha, Nebraska