Bank One Corporate Center, Chicago

The 1.8 million-sq.-ft. Bank One Corporate Center in Chicago has a foot in the past and another in the future.

The 37-story skyscraper incorporates advanced technology and is built on the site of the Fair Store, which was completed in 1892 and demolished about 15 years ago. The new building reuses the Fair's original basement walls and is supported on the existing caissons.

Reuse of the existing foundation infrastructure was a critical decision that impacted the design, construction, budget and schedule. Time and cost savings were realized by coordinating reuse of the existing structure and foundation wall to stabilize the basement excavation temporarily and support the new construction permanently.

This was achieved by performing selective demolition, limited supplemental stabilization and renovation and new construction.

The perimeter foundations walls were left and approximately 125 caissons in a 37-ft.-deep hole. Laid atop the caissons was a 48- to 54-in.-thick reinforced concrete mat slab.

The reason for the mat slab is the column spacing of the new building does not coordinate with the caisson structure of the previous structure. The mat slab transfers the loads from the new building above to the existing caissons below.

Because subways on the east and west flank the building, grade settlement points were established and vertical inclinometers were installed during foundation work to monitor movement of existing structures and surrounding streets.

A tight schedule was accommodated in other ways. A fast-track regimen was developed that allowed for the early release of structural steel, concrete, vertical transportation and curtain wall packages for pre-construction bidding, all while continuing project coordination and document production.

Two-In-One Structure

The building's location in the Loop's Central Business District brings about a dual persona.

The tower is an office building that bows to the financial district along Dearborn Street.
In addition, an 11-story element that contains retail and office space on State Street reinforces the thoroughfare's role as a shopping mecca.

Each component has its own entry and associated lobby that reflects the separate functions and building populations.

About 1.5 million sq. ft. of office space is in the development and approximately 100,000 sq. ft. of retail area is on three levels.

Parking for more than 200 cars is on two sub-basement levels. Central mechanical services are housed on levels one, 11 and in a penthouse. Ten loading docks are available.

Amenities include building setbacks from State Street and at the tower corners, a landscaped roof garden, ground-level public arcade along Dearborn and streetscape/landscape improvements along the public right-of-way.

Has Client, Technology Focus

The building was designed to accommodate dynamic clients, such as anchor Bank One Corp., with a demand for rapidly growing, highly flexible information technology systems.

The typical floor design features high ceilings and open-floor spaces to maximize the amount of natural light.

The floors are reportedly easily adapted to multi-tenant configurations, with floor sizes ranging from about 33,500 sq. ft. to 62,800 sq. ft.

Has Air-Plenum System

The structure is a technology-ready building and designed to serve the communication technology needs of today and anticipate future technology needs.

For instance, the building is equipped with a raised-floor pressurized plenum air supply. The system reportedly provides improved air quality, reduced energy consumption, increased temperature control and tenant flexibility.

Unlike traditional office buildings incorporating ductwork in the ceiling, the air in Bank One Corporate Center will be distributed via air columns through the floors, enabling occupants to adjust heat and air conditioning at every workstation through the use of floor diffusers.

The system is fully accessible and allows for use of modular wiring for distribution of power, telecommunications and data.

With studies that show occupants frequently change office space yearly, the environment at Bank One Center is reportedly more flexible than conventional structures. That should in turn lower tenants' space reorganization, or "churn," costs that result from the inevitable changes businesses make to work environments as staffs transition and corporate needs change.

Multiple technology risers with expansion capability for redundancy, growth and flexibility further support the building's mission to serve technology-based businesses.

Looking Up

The building is in a high-visibility location, facing the Federal Building Plaza and surrounded by examples of classic Chicago architecture.

The Bank One Corporate Center's concept was to keep the curtain wall simple yet provide a degree of refined detail befitting a building to be perceived primarily at close range.

The building's aluminum and glass curtain-wall design is to express the technological sophistication of its architectural, mechanical, data and telecommunications systems with a high-tech exterior image.

The jury said, "From the air-plenum system to the reuse of the existing foundations, this project was a challenge. To keep up with the fast-tracked schedule, the team really had to have their ducks in a row. It's a nice addition to the skyline."

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