For the architects, engineers, and builders of Hayward's new city hall, the project presents an exciting challenge:

• A variety of historical, cultural, and physical constraints must be pulled together to create an open and dynamic environment that will unite citizens and government.
• The structure must be safe in the event of a major earthquake.
• It needs to be built quickly and within the city's budget.

NEW CITY HALL TO UNITE DOWNTOWN HAYWARD

The new Hayward City Hall design is the culmination of several years of city planning, public working sessions, hearings, and finally architectural design. The city hall is meant to provide a focal point for downtown activities during the work week and on weekends.

"The rotunda acts as a city focal point," observed Jeffrey Heller, president of Heller-Manus, the new city hall's lead architect. "From the rotunda, one can see the retail and restaurant corridor, the public transit path, the central plaza, and several civic buildings, including the library and post office."

Borrowing a planning concept found commonly in most European countries, the City of Hayward has chosen to locate the new city hall a mere 300 feet from the Hayward BART station. "This will encourage greater use of public transit for both city employees and residents," said Jesus Armas, Hayward's city manager. "And because it will be so close to other public buildings and shopping, we expect that residents will find it to be an inviting place to spend some time."

The building's design pulls in architectural elements from the city's past and present:

• Design details from Hayward's old city hall on Mission Blvd. will be apparent on the new facility's facia
• Hayward's Early California and Spanish heritage has been incorporated into the design
• Careful attention has been paid to make sure the facility will fit in with the existing neighborhood
• A public galleria, designed to support Hayward's community arts program, will extend almost the entire length of the first floor
• An easily accessible, one-stop shopping area for residents to obtain permits and receive city services will be built
• An open, public plaza just outside the city hall's rotunda provides space for use during the week and for public markets and events on weekends

"The whole thrust of this design is to convey a feeling of open government," concluded Mr. Heller. "The high proportion of public space within the building should help promote the interaction of citizens with government."

DESIGN/BUILD PROJECT DELIVERY

To meet the City of Hayward's requirement to move into the new city hall by the end of 1997, the project has been approached using a fast-track design and construction technique known as Design/Build. This proven project delivery system is used in fast-paced projects to shorten the design and construction cycle for complex facilities. Developing and building public facilities using the Design/Build approach has become more popular in recent years as governments have discovered its advantages.

Under the Design/Build system, the City of Hayward has contracted with a single entity to provide architecture, engineering and construction services for a single guaranteed maximum price. In addition, any cost savings are passed on to the City of Hayward. But the key to Design/Build is that construction can begin after the physical sizing and structural design are complete and before such things as utilities and interior detailing are specified. By overlapping the various stages of design and construction, the entire development process can be compressed and a project more quickly completed.

"DPR has used Design/Build for many extremely complex semiconductor manufacturing projects," noted Gerry DeWulf, DPR Construction's preconstruction manager for the new city hall. "It has helped us speed up project delivery while maintaining the high quality required in chip manufacturing plants."

An important ingredient for success using the Design/Build approach is the active partnering and cooperation between the facility owner, the Design/Build construction manager, the various designers, and the builder. For the Hayward City Hall project, several entities have come together to create a high performance team:

• The City of Hayward - the facility owner
• Hayward City Center Company, LLC, which is managed by SARES-REGIS Group of Northern California - the Design/Build construction manager
• Heller · Manus Architects - the building designer
• KPFF Consulting Engineers - the structural engineer
• DPR Construction - the builder

"A public/private partnership like is benefits everyone," noted Jeff Birdwell, Hayward City Center Company, LLC's construction manager for the project. "Most importantly, the City of Hayward will get a state-of-the-art city hall delivered on-time and on-budget."

ENGINEERED FOR SAFETY

The seismic design specifications for Hayward's new city hall call for a structure that can continue to operate after a magnitude 7.0 earthquake on the Hayward fault, as measured on the Richter scale and is life-safe during and after a magnitude 7.5 earthquake on the Hayward fault. The last earthquake believed to have approached 7.0 in magnitude on the Hayward fault, which lies just 700 feet from the new city hall, occurred in 1868.

The system selected to achieve these goals is known as a base isolation system, which is widely used today in many essential facilities, including hospitals and emergency communication centers. Base isolation is also being used in the new international terminal at San Francisco International Airport and in San Francisco's U.S. Court of Appeals.

The new Hayward City Hall will rest on 53 friction pendulum isolation bearings, each of which consists of an 11 inch diameter stainless steel slider and a 56 inch diameter concave plate with a stainless steel surface. The sliders are attached to the bottom of the building's columns and rest within the concave plates, which are attached atop 6 foot square, 7 foot high concrete pedestals below grade. During an earthquake, the building is designed to slide up to 22 inches in any horizontal direction.

To help slow and eventually stop the building's movement relative to the ground during an earthquake, 15 viscous dampers join the building to thrust blocks below grade. The 14 foot long, 12 inch diameter viscous dampers, originally developed by the aerospace industry and similar to those used on the Space Shuttle launching pad, look like and are designed to act like giant shock absorbers, stopping any horizontal motion in a controlled manner.

"Each component of the isolation system has been carefully tested," said Marc Press, KPFF's lead structural engineer on the project. "We have extensively modeled both the base isolation system and the structure above it to ensure that they can withstand the input loads specified. Plus, a peer review group, which included third-party structural engineers and geotechnical engineers has corroborated the design."

BUILT TO LAST

The base isolation equipment to be installed under the structure creates special challenges during construction explains Mr. DeWulf of DPR. "Steel and concrete tolerances are very precise in this design. And, since the building can move up to 22 inches in any direction during an earthquake, exterior materials need to be very securely fastened to the structure." To ensure accuracy, DPR has placed special emphasis on the pre-construction phase of the project. DPR's construction engineers have been working closely with the architects and structural designers to make sure the construction drawings are correct. "We want to catch potential problems before we start so they don't occur as the structure is built," said Mr. DeWulf.

Special emphasis will be placed on the connection points where power, gas, water, and sewer enter the building. "The utilities are all on articulating arms or use flex connections so they can move along with the building. Actually, they'll be pretty easy to build," said Mr. DeWulf.

The elevator system has also created a special challenge to the builder. Because the elevators are part of the building yet must reach to the basement parking area which is below the base isolation equipment, the elevators must "hang" from the building into the basement and provide the necessary freedom of movement during an earthquake. DPR will form the basement elevator core by integrating it with the concrete pour for the first floor. "It's an elegant solution to a difficult problem," noted Mr. DeWulf.

Finally, DPR has developed a site logistics plan to minimize disruption caused by construction activities. Among other measures DPR will:

• require trucks bringing in equipment to follow a route that avoids residential and retail areas
• begin construction after 7:00 a.m. and stop by 5:00 p.m. every day
• minimize dust by watering down the site, cleaning the streets, and running all trucks through wheels washes as they exit the site.