The team for the $165 million Robert H. Lurie Medical Research Center had to dig deep.

The facility in Northwestern University's downtown Chicago campus required a cavernous space below grade, said Tony Louvis, project manager with New York-based Davis Brody Bond LLP, the architect.

The 40-ft.-deep basement will contain holding areas for animals used in medical research. Because of regulatory requirements, a large number of mechanical lines will feed the space, and redundant services protect against loss in case a system goes down.

"Many animals are the products of five years of breeding," Louvis added. "If anything should happen to the animals, it's a catastrophic loss for the people doing the research."

The construction team was concerned about the project's location in the city's building-dense Streeterville neighborhood, said Joel Klahn, project executive in Chicago with Turner Construction Co., the general contractor. Pressure from adjacent structures on the excavation walls could cause them to move. And, unintended outcomes could include the settlement of the street or adjacent buildings, the cracking of foundations or damage to utility lines.

As a result, an earth-retention system that employs grouted steel tiebacks, or tendons, will make the building's foundation rigid and secure.

"It was a lengthy review with the city to ensure we wouldn't damage the public way or any public utilities," Klahn said.

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Let's Dance

The installation of the tieback system was choreographed carefully.

The Passavant Pavilion previously on the spot was demolished in the latter part of 2001, and steel sheeting was driven the following spring about 60 ft. deep into the site perimeter. Excavation began soon thereafter.

The installation of the approximately 950 permanent tiebacks under the surrounding streets and properties was done over three levels of depth, said Ron McAllister, Turner site superintendent.

Whaler beams were installed horizontally on the sheeting's interior face, also at three levels. Through the beams, 4-in.-diameter holes were drilled about 50 to 60 ft. in length. A grout tube and either steel rods or steel cables were inserted, and grout was pumped in under pressure and allowed to set.

Bolts on the sheeting's inner face were tightened to raise the tension to precalculated levels, Louvis said. The friction of the soil against the hardened grout ensures the stability of the foundation and that of the surrounding properties.

"We're inducing stress in the cables to ensure that when the sheeting wants to move, it can't," Klahn added.

The sheeting has a 10-ft.-deep toe below the basement's lowest level to help anchor the base of the sheeted wall. An independent foundation wall made of concrete rounds out on the below-grade interior.

The independent wall helps ensure the space remains dry, Louvis said. The site is only about a block from Lake Michigan.

Enhancing the Medical School

The facility is being built to elevate the stature of Northwestern's Feinberg School of Medicine.

"The way you do that is to increase the research base," Louvis added.

Construction of the 418,000-gross-sq.-ft. facility on the southeast corner of Superior and Fairbanks streets is expected to finish in November.

The 12-story building will feature nine floors of laboratories, and each level will have 12 laboratories, said Jo Le Mieux-Murphy, project administrator with Northwestern's Facilities Management Design & Construction department. The structure will house about 700 researchers, postdoctoral students and laboratory technicians.

Research in many advanced areas - cancer, genetics, neurology, infectious diseases and nanotechnology - will be conducted in the building.

The remainder of the facility will include lecture halls, auditoriums and dining on the first floor and mechanical equipment on the second and top levels, in addition to the basement.

Sensitivity to the surrounding campus buildings, many featuring Gothic design elements, was important, Louvis said. Steel columns will be exposed, and the steel crossing the top of the building will call to mind flying buttresses. Architectural precast dresses the building.

The facility is named after the late real estate developer whose wife, Ann, a Northwestern trustee and principal of Lurie Investments Inc. in Chicago, made a $40 million gift for the project.

Setting Up the Site

The replacement or modification of utility lines around the site was done as a precaution to ensure that they would not fail in case settling did occur.

"The project inspired the utilities to do something they had always wanted to do," added Gerald Pinka, chief maintenance engineer in Facilities Management - Operations with Northwestern. Many of these systems were originally built in the early part of the previous century and were not sturdy enough to handle movement were it to occur.

Gas mains and branches were replaced, steam lines were retrofitted with flexible joints and a water main on Superior was taken out of service. The replacements of some lines were extensive.

For instance, steam lines were replaced on Huron and Superior streets. Because of the demolition of Passavant, a trench was dug on the south side of the property to accommodate the reroute of a steam line originally connected to that structure.

For gas, an approximately 6-ft.-wide trench was cut on three streets surrounding the site.

A large number of footings for the support of buildings previously on the site was unearthed and removed, including wood pilings with concrete pile caps and caissons. More than 100 piles were discovered.

Care was taken during removal. "We couldn't extract [the footings] for fear it would encourage movement of the surrounding soil and structures," Klahn said. A powerful backhoe was used to break apart pieces and scoop them out.

Wiring a Lab

Planning was done to accommodate the large number of mechanical, electrical and plumbing systems.

Two meetings were held every week for nine months to coordinate the project and make it understandable, Klahn said. "There were probably 15 people involved close to full time taking the design and making it into a format the tradesmen in the field could use to install the systems," he added.

Mock-ups were fabricated for the laboratory casework to ensure the correct placement of plumbing, conduit and drawers. For the building's lower levels, the most complicated interstitial spaces were also replicated to ensure they were accessible after completion of the building and could be maintained.

The floor-to-floor space on the lower levels is a relatively generous 20 ft., and because of the complexity of the MEP system, 12 ft. was devoted to the equipment. Air handlers were stacked two high on the second floor and three high in the penthouse.

Sixty-four fume hoods will provide independent exhaust to the laboratory spaces. They feed the air into nine high-velocity fans for exhaust.

Clean rooms that are to arrive in modular panels will be installed on the building's 11th floor. Because of the sophisticated research planned for the facility, one clean room will be installed inside another.

The large number of materials for the project in the crowded city neighborhood caused logistical headaches.

A lot at Erie and Fairbanks streets was available to stage selected materials such as precast and steel.

But the just-in-time method was used for many other deliveries, such as the 46 trucks needed to haul the second-floor equipment alone. Even 28 deliveries were required for the cranes, 10 for the service crane and 18 for the tower crane.

The German tower crane is only one of two in the country, Klahn said. Powered by electricity, the crane is noiseless.

"People want to sleep at the rehabilitation center near the site," he added.