ABN AMRO Plaza

Project of The Year: Commercial

ABN AMRO North America had specific needs when it decided to consolidate its Chicago offices and build a facility with expansion flexibility.

The dimensions and site's location at Madison, Clinton, Jefferson and Washington streets influenced the project's configuration and phased development.

The 1.3 million-sq.-ft., 30-story phase one tower features a distinctive geometry, orientation and street level plaza and is part of a complete development that includes the yet-to-be built, 1.2 million-sq.-ft. phase two tower.

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Space for Specific Facilities

The owner required space for specific operations, such as check and data processing, to support its technology-based business.

Large floor plates were best suited to these requirements, and the six-story base on a full-block site resulted.

At the same time, the owner needed office space with its own programmatic needs, such as security to support seven-day-a-week, round-the-clock operations.

Current and future space needs were addressed by phasing the office into two towers.

The issue arose of placing the two towers atop a space with adequate visual separation between. The site dimensions did not permit multi-phased towers to sit side by side with acceptable spacing.

Chamfering the towers' opposite corners, creating minimal overlap of tower masses and maximizing views from both towers addressed this constraint. The unconventional geometry that results also created a distinct presence.

A stainless steel point extends from grade level the full height of the building and helps establish a street-level presence.

The angular shape creates a roof area at level six, which will eventually nestle between the two towers. The roof garden has plantings over half of its area along with light-colored pavers to reflect light and heat from the podium's roof.

The structure is set back on its site with a landscaped plaza at ground level by the Madison Street entrance, preserving a sense of openness in a dense, urban area and allowing distance from the residential Presidential Towers.

Addressing City Needs, Security

Circulation was a challenge because security was an overriding consideration in the design.

The city of Chicago required retail functions on the ground floor with public access, which conflicted with the strict security of the owner's program. The solution was to create a double-level lobby.

The lower-level lobby accommodates public access to a retail arcade connecting two major east-west streets at ground level. A mezzanine lobby, which is exclusively for bank personnel, provides security control for critical spaces.

The bridge across the lobby was designed with access to the phase two tower, providing the flexibility to have a single- or double-level lobby in the second tower.

'Simple Vanilla Box' Wanted

The owner's mandate was to develop a "simple vanilla box." The demand for simplicity led to use of stainless steel cladding.

The interior also followed the concept of simplicity. The terrazzo floor, for instance, is an economical material that allowed detailing that respond to the building's geometry.

The building incorporates an under-floor air plenum air distribution, a system believed to be efficient for adaptability.

The air plenum provides fresh air through floor diffusers and draws return air through ceiling diffusers. This requires less energy due to convection.

As building occupants heat air within their area, the used air rises toward the ceiling and naturally draws the fresh air from the floor area. Occupants benefit from the higher average air quality.

Mechanical, electrical, plumbing and fire protection systems are designed with redundancy to ensure uninterrupted operations. Security and building automation systems are controlled from a central command center.

Because of the need for redundancy, the stand-by systems required a large amount of space. This pointed to the systems' sensitive integration into the building geometry and led to the offset-wall design at the mid-point and penthouse levels of the extension wall.

Security mandates required that all staff parking be in the building and accessible through security entrances, resulting in internal loading docks at grade and multi-level parking for 270 cars below grade.

The jury said, "The complexity of the project in an urban environment is impressive. It took a lot of construction. The project required a sustained effort to satisfy the client and the city.

"The structure's high-technology elements, like the under-floor air-plenum system, make the project unique. And those elements help communicate the high-tech image the client sought."