Sanibel Bridge Repair, Structure "B" Span Replacement

Managing Agency: Lee County Department of Transportation

Primary Contractor: Zep Construction

Primary Consultant: URS Corporation

Nominated By: Lee County Department of Transportation

Southwest Florida is a haven for tourists from all over the world, and Sanibel and Captiva Islands are world renowned for their beautiful beaches and a variety of wildlife. A large part of the charm of the islands is their location off the coast of Lee County. Sanibel and Captiva are connected to the mainland via the Sanibel Causeway, a series of three bridges (one bascule bridge and two fixed spans) and two spoil islands. These bridges are the lifeline to Sanibel and Captiva. All commercial goods must be transported to the numerous businesses, groceries and restaurants via this causeway. The causeway also carries residents and visitors, as well as all construction vehicles, to and from the islands.

During a routine inspection on January 6, 2003, cracked beams that hold up the bridge deck were identified on the middle bridge of the causeway. Trucks heavier than 10 tons were immediately required to reduce their speed to 10 miles per hour as they crossed the causeway. Upon further discussion with its consulting engineer, Lee County Department of Transportation prohibited all vehicles over 10 tons from crossing the causeway until emergency repairs were completed, and reduced the speed limit for all other vehicles to 10 miles per hour.

Within a week of discovering the cracked beams, Lee County announced a 36-hour closure of the causeway to allow for the replacement of the bridge beams and decking. Emergency repairs consisted of replacement of a 48' span of Bridge B, consisting of four concrete beams, concrete deck and guardrail, with a steel span of six beams, steel grate decking and three-rail guard rail system. The contractor was contacted on January 7 and the design-build effort was begun in conjunction with the temporary bracing efforts of the County's bridge maintenance crew. The contractor and consultant met to agree on the design parameters, and fabrication of the new span began on January 8.

Fabrication of the steel replacement span was scheduled for completion in one week and bridge closure was scheduled for January 19 at 10:00 p.m. with projected reopening on January 21 at 6:00 a.m. The bridge was closed on schedule and demolition of the span began. Removal of the existing span and installation of the prefabrication steel span (two pieces with onsite interconnection) were completed on January 20 and the bridge reopened to traffic at midnight, six hours ahead of schedule. The total time from discovery of the cracked beams to replacement of the span was 14 days, which included a bridge closure of only 26 hours.


Quarton Lake Restoration Project

Managing Agency: City of Birmingham, Michigan

Primary Contractor: Restoration Dredging

Primary Consultant: Hubbell, Roth & Clark, Inc.

Nominated By: APWA Michigan Chapter

The City of Birmingham obtained Rouge River National Wet Weather Demonstration Project grant funding to restore Quarton Lake, a 13.2-acre impoundment of the Rouge River, as an environmental demonstration project for other communities in the Rouge River watershed. The lake's maximum length is 2,000 feet and maximum width is 450 feet. The mean width is 283 feet. The deposition of sediment and pollutants within the lake over the past 30 years led to impairment of the water quality. The lake was previously dredged in 1974. Since then, sediment from upstream sources and severe bank erosion have contributed to the degradation of the lake.

Community acceptance, understanding and support of the restoration project were critical due to the lake's residential location, surrounded by homes and a recreational park area. Extensive public input was solicited during the design process through a series of eight community meetings during a ten-month timeframe. The lead consulting engineer for the City and the local residents developed and implemented a comprehensive plan to restore Quarton Lake using watershed management and adaptive management approaches. The plan included dredging the lake to remove accumulated sediments, an upstream sediment trap installation, carp removal, game fish stocking, waterfowl implementation, shoreline erosion stabilization using soil bio-engineering, asphalt and concrete pavement removal to eliminate a direct runoff source to the lake, shoreline soil amendments, wildlife habitat enhancements, bottom aeration, invasive plant removal and wetland/aquatic plantings.

The project included stabilization of approximately 5,535 lineal feet of shoreline. Non-native plants such as garlic mustard and buckthorn were identified and removed. Although they seem pretty and harmless, such plants proliferate once they start growing in an area, stifling the growth of native plants that serve an important ecological purpose. Shoreline stabilization was accomplished through the use of environmentally-friendly, economical and natural coir logs, made from 100% coconut fiber.

The goals for the Quarton Lake Restoration Project were to cost-effectively restore the aquatic resources and park for the community and watershed area. Lake monitoring and a watershed assessment provided data to evaluate existing conditions and potential problems. This data also provided a basis for design considerations and a baseline for evaluating the effectiveness of restoration efforts. The construction was completed in 2003 within budget and without any residential complaints. With the restored habitat for fish and wildlife, improved lake access, and a picturesque park-like setting, the Quarton Lake Restoration Project not only restores life to the environmentally-sensitive lake waters, but also restores vibrancy to the community by enhancing the residents' quality of life, both aesthetically and recreationally.


Multi-Site Landfill Closure and Park Renovation Project

Managing Agency: City of Nashua, New Hampshire, Division of Public Works

Primary Contractor: Littleton Environmental Services, Inc.

Primary Consultant: Camp Dresser & McKee, Inc.

Nominated By: APWA New England Chapter

The City of Nashua's Multi-Site Landfill Closure and Park Renovation Project involved the reconstruction of five city parks and recreational areas formerly used as municipal solid waste landfills. These parks were previously established in the 1960s over landfills that received non-engineered soil caps. This method of capping, landfill closure and park construction met the existing standards and practices at the time; however, over the years, park conditions had deteriorated due to the existence of underlying solid waste which included municipal solid waste, friable and non-friable asbestos and tannery waste. Prior attempts to remedy these sites dealt only with treatment of the observable symptoms and failed to develop a comprehensive strategy to provide a "state-of-the-art" landfill closure and quality park.

In a multi-pronged approach that acknowledged both environmental concerns and recreational needs, the Division of Public Works developed an innovative plan that assessed and restored the five existing parks, which manifested problems related to their prior use as landfills. Differential settling, inadequate drainage, exposed waste, unstable slopes, potential water quality impacts and asbestos-contaminated materials were identified as significant environmental issues at one or more sites that would be addressed in the designs for closure and recreational improvements.

The project required effective integration and coordination of funding, local and regulatory approval, design, and construction. Solutions were reached for several complex environmental problems, including landfill gas management, stormwater drainage, settlement, and long-term cap competency. A detailed health risk assessment was completed that involved determination of possible risks posed by contaminants potentially present in the completed reuse project. This was necessary to gain public acceptance and ensure confidence in the final product. The City's objectives were achieved by incorporating the final design techniques and systems such as:

  • Active gas management and collection
  • Turf irrigation with precise management of root zone moisture content, resulting in reduction of moisture infiltration
  • Significant improvements in drainage with the installation of a geocomposite drainage layer, and
  • Optimization of turf and sod growth with the use of a "Class A" Biosolid and sand mix for the final vegetative layer.

Construction commenced on four of the five sites by the end of 2002. Three of the five sites were substantially completed by the end of 2002, with final completion of all of the sites occurring in the fall of 2003. In just over two years, the landfill closure and improvement actions implemented at these five sites added over 30 acres of premium parks and recreational areas to Nashua's park system while substantially increasing the level of environmental protection.


Dams and Locks on the North Canadian River

Managing Agency: City of Oklahoma City, Oklahoma

Primary Contractors: C-P Integrated Services, Inc.; Wynn Construction

Primary Consultant: Triad Design Group, Inc.

Nominated By: City of Oklahoma City, Oklahoma

In the early 1990s, Oklahoma City's leaders determined that a number of projects were required to provide its citizens a better quality of life and, in turn, create potential future economic benefit for the City—and thus the Metropolitan Area Projects (MAPS) was born. One of the nine key project venues associated with MAPS was the revitalization of the North Canadian River and construction of three low-water dams: the Eastern Avenue Dam located on the downstream side of the Eastern Avenue bridge; the Western Avenue Dam located 2,200 feet downstream of Western Avenue; and the May Avenue Dam located 500 feet upstream of May Avenue.

The foundation for the Eastern Avenue Dam consists of approximately 240 H-Piles driven into bedrock. At the completion of driving the H-Piles, the horizontal structural concrete was constructed with four piers connecting the gates to the structure. The three hinged crest gates for the structure have dimensions of 100 feet long by 13 feet high. The two massive gate sections were then bolted together after they had been set between the piers. The dam has an associated control house with a hydraulic power unit for gate operation.

The decision was made to construct the Western Avenue Dam on roller compacted concrete (RCC). The RCC was batched onsite with the use of a pug mill. The RCC was installed in 12-inch lifts (approximately 25 lifts) until the desired top elevation was achieved. Following placement of the RCC, horizontal structural concrete was poured in place along with seven piers for connecting the gates to the structure. The six hinged crest gates for the structure have dimensions of 50 feet long by 10 feet high. This dam and the May Avenue Dam are unique in that they both have 25-foot by 60-foot boat locks that allow passage of watercraft between the lakes, which have differing water elevations.

Locating the May Avenue Dam 500 feet west of May Avenue allowed a diversion channel to be constructed around the project site. The diversion channel was constructed to divert normal flow and allow the contractors to work on the entire structure at one time. The depth to bedrock on this project was approximately 10 feet and the dam was founded on mass concrete stabilized with a vertical structural concrete shear key. Upon completing the foundation, seven piers were constructed to connect gates to the structure. The six hinged crest gates have dimensions of 50 feet long by 12 feet high. The gates were delivered by rail in 50-foot sections and set between the piers.

All three dams were constructed with no documented lost-time injuries.


Restoration of the Belltower and Front Facade of Fire Station #1

Managing Agency: City of Roanoke, Virginia, Engineering Division

Primary Contractors: City of Roanoke, Virginia, Department of General Services; Southwest Restoration Company

Primary Consultant: Hill Studio, PC

Nominated By: City of Roanoke, Virginia, Department of Public Works

Fire Station #1 was built by the City of Roanoke in 1906. The facade bears a resemblance to many early 18th Century English town halls. It was constructed primarily of clay brick with a sandstone water-table on the front facade. The building is approximately 50 feet wide, 100 feet long and 85 feet high (to the top of the belltower dome). Fire Station #1 is the oldest firehouse in continuous operation in the state of Virginia, and is listed in the National Register of Historic Places.

In June 2002, an assessment of the belltower on Fire Station #1 showed that there was visible deterioration of the wood cornice below the gables of the belltower. In June 2003, RFPs were sent to several architectural firms that specialize in historic preservation projects. The Department of Engineering completed the Project Manual in August 2003, and a formal bid package was ready for distribution on August 22, 2003. Of the actual construction costs, including carpentry, masonry, painting and lead abatement, approximately 60% was awarded to Minority Business Enterprises.

The presence of lead-based paints came to the attention of the Engineering Division through the Department of Environmental Services and Emergency Management. Lead abatement was undertaken by stabilizing the paint film. Although this process delayed the starting date, the project was substantially complete on December 15, 2003 and the building was formally reopened on December 19, 2003. Actual construction time took 78 days, besting the anticipated 90 days by almost two weeks.

All during the project, all of the personnel involved had to work around very severe weather conditions. One particular trade that was affected significantly involved masonry. The brick masons used a high-lime mortar for all of the re-pointing on the building. This particular type of mortar is resilient and long lasting, but is easily damaged by low temperatures if not fully cured. In an effort to reduce the type of failure that is typically associated with the freeze-thaw of lime mortars, the masons worked only on relatively warm days when non-freezing nighttime temperatures were forecast. This meant that approximately half of the scheduled workdays were not appropriate for re-pointing or masonry repair. Nevertheless, masonry was completed on schedule. The painters made a similar effort on this project.

Worker safety was a paramount consideration on the project. Systems scaffolding was installed to meet or exceed OSHA standards. Hardhats and fall-protection harnesses were mandated by the project manager in accordance with OSHA regulations as appropriate. No injuries were reported, and there was no lost time during the execution of the work.


Lenexa Conference Center

Managing Agency: City of Lenexa, Kansas, Public Works Department

Primary Contractor: McCown Gordon Construction

Primary Consultant: Rafael Architects, Inc.

Nominated By: APWA Kansas City Metro Chapter

The historically significant Thompson Barn, sited just south of the recently restored Lackman/Thompson house, has been a visual landmark in the region for many years. The City of Lenexa was determined to restore and renovate the barn. A high-tech conference center was designed and constructed to fill the public void of high-tech conferencing in Lenexa. Today, the Lenexa Conference Center is available for use by the public, the civic community and the business community.

The barn's historic pedigree demanded that care had to be taken not to alter the barn's primary facades or the main floor area while providing a functional and optimal solution to the program requirements. The barn's historic and cultural context required the sensitivity to allow the barn to remain the prime focus and not destroy the barn's relationship with the land or other buildings on the site.

Working to limit the potential harm that the renovation would inflict on the historic building, the consultant determined that meeting the program requirements would necessitate a new addition. This new addition would provide lobby space, circulation, mechanical systems and toilet rooms. Drawing from the barn's original context, the consultant concluded that the addition should not only be placed underground, but also covered with native grasses. Additionally, the landscape would include limestone outcroppings, oaks, cedars and staghorn sumac, elements that are common in rural Kansas.

A sheer glass connection was designed to reinforce the separation of the two structures and allow for unobstructed viewing of the historic structure. The glass is actually slotted into the stone to eliminate heavy window framing that might otherwise be attached to the historic structure.

The Lenexa Conference Center project was filled with unusual conditions. The project goal of turning an old barn, built in the 1930s, into a state-of-the-art high-tech conference center is in itself a very unusual condition. Making the building weather tight while still retaining the historic nature of the barn, controlling sound reverberation and separation were but a few of the difficulties. Solutions were found in the use of the lightweight concrete floor overlay, carpeting, and special compression sound equipment that controls unwanted noise and echo. A new roof, matching the existing corrugated metal roof, was designed to be applied over the existing roof. This allowed the barn to remain covered during construction, reducing the potential of wind and rain damage to the historic building. Significant amounts of groundwater are directed away from the building's interior with the use of redundant drainage systems, one outside of the stone foundation walls and another inside by an underslab drain field and sump.


Baldwin Water Treatment Plant Rehabilitation

Managing Agency: City of Cleveland, Ohio, Department of Public Utilities, Division of Water

Primary Contractor: Shook/Kokosing Joint Venture

Primary Consultant: Malcolm Pirnie, Inc.

Nominated By: City of Cleveland, Ohio, Department of Public Utilities, Division of Water

The major renovation of Cleveland's 80-year-old Baldwin Water Works Plant, a registered historic landmark, was a most challenging project. The assignment was to double the capacity of half the plant's 40 existing filters, located in one of its two Filter Wings, so as to free space for new chemical storage and feed equipment to be installed in a future phase. At the same time, the interior and exterior of the Filter Wings were to be restored, in many places to their original condition, or, where restoration was impossible due to the process improvements, to preserve the building's historical significance through unique visual effects.

The Filter and Administration Buildings have a total floor area of approximately 268,000 square feet. The Filter Building construction consists of concrete reinforced walls below grade and brick and sandstone walls above grade with a combination of flat roof and sloped slate shingle roofs. The center pavilion of the Administrative Building is a three-story structure with the main entry at the second floor accessed by a series of exterior stairs.

The restoration work preserved and even enhanced the plant's many unique architectural features—a beautiful, multi-stories-high bronze and glass entrance with a sculptured motif of leaves and symbols, the filter gallery itself with its paneled wood ceiling, marble and bronze filter operation tables, and quarry-tiled floor.

To keep the "vintage" look, the engineers used creative approaches. HVAC equipment was added to the operating gallery by installing ductwork in the roof supports and painting it to match the ceiling. Although the filter operation is automatic, there is no control equipment on the operating gallery floor, keeping the 1925 look, while at the same time hiding what was added.

Because the pipe gallery had to be dehumidified, piping observation wells were enclosed. To preserve the architectural look while providing visual access, glass pavers were installed in the floor and enclosed by refinished railings. Near each filter, an inconspicuous panel door conceals a digitally controlled, valve master control station with a computer port, with a marble counter supported by "historic"-looking brackets for laptop use. "Vintage"-looking architectural grills supply makeup air to the operating gallery.

In the completely renovated interior, new walls isolate filters from the operating area, preserving the original architectural look. High-tech filter controls are concealed in a closed control room, and air handling units are located outdoors. Much exterior stone and metal work was rehabilitated, and the rooftop portico was restored, with brick pavers installed; planter benches and architectural "doghouses" conceal HVAC and other equipment on the rooftop. This rooftop surface was preserved for public gatherings.


Liberty Memorial Restoration and Adaptive Reconstruction

Managing Agency: City of Kansas City, Missouri, Parks and Recreation Department

Primary Contractor: J.E. Dunn Construction

Primary Consultant: ASAI Architecture

Nominated By: APWA Kansas City Metro Chapter

Liberty Memorial has stood as a symbol of Kansas City's honor and patriotism for more than 78 years. The memorial was originally built in 1926 to honor those who sacrificed everything for our freedom in World War I. But the funding for the memorial came from citizens who set out after the war in 1918 to raise more than 2.5 million dollars in only 12 days. This World War I memorial complex is the only one in the United States.

The memorial is graced by a 217-foot observation tower. Two museum buildings flank the tower. Other distinctive features of the memorial include the two large carved sphinxes, a stone frieze that is 148 feet wide by 18 feet tall, the courtyards and stairways, and the site dedication memorial of the five Allied leaders.

The memorial had been closed since 1994 due to deterioration and public safety concerns. The citizens of Kansas City stepped forward again to renovate the memorial in 1998 by passing a sales tax and lobbying for federal funding. Kansas City's drive ensured that the memorial would stand high on the hill in remembrance for future generations.

The restoration project scope was varied and prime consideration was given to maintaining the historical integrity of the memorial. Work included repair of the limestone walls and planters and stonework, renovation of the tower elevator, replacement of the deck and walkways, restoration of the mosaic tile floors and windows of the museum building, art restoration of the museum murals, installation of new HVAC units, restoration of the boiler that produces the tower flame, and adaptation of the grounds and buildings to ADA standards.

The museum buildings have been restored and updated featuring newly-designed exhibits. New glass cases house exhibits from the Liberty Memorial Association's vast collection of WWI artifacts, much of which has never been on display due to a lack of exhibit space. Items of interest include uniforms, medical supplies, and letters from soldiers.

The murals were badly deteriorated with holes and rotting substrate before being completely restored following an innovative research and conservation process. Ornamental plaster ceilings have been repaired using molds made onsite from existing ornaments and reglazed in layers to provide an aged patina. The original lino-mosaic flooring, in-laid with an intricate six-color diamond pattern, has been fully repaired with custom-colored material to match the original. The floor was stripped and sealed with linseed oil to bring out the original color and preserve the original patina.

A security office and security system have been added to protect the revitalized monument and museum buildings.


Salt and Vehicle Storage Facility

Managing Agency: Village of Orland Park, Illinois

Primary Contractor: Chicago Heights Construction Company

Primary Consultant: Interplan Practice

Nominated By: APWA Chicago Metro Chapter

The Village of Orland Park lies approximately 30 miles southwest of downtown Chicago. The Village covers 18 square miles of land and has a population in excess of 52,000 people. The population of the Village has grown steadily at an average annual rate of 4% for the last 20 years.

The metropolitan Chicago area experiences an average snowfall of approximately 42 inches. The Village of Orland Park has jurisdiction of over 400 lane miles of arterial, collector and local streets and recently has initiated the use of traffic calming measures such as traffic circles and chicanes. Over the last eight years, the Village has used about 4,100 tons of salt each year. To this end, the Public Works Department designed the Salt Storage Facility so that it would be capable of storing enough salt, if necessary, to combat a large number of snow events without replenishing its supply.

Construction of the Salt Storage Facility was unique in that the facility was built on an old U.S. Army Nike Missile base. Three missile silos were located on the property, and the concrete roof of one of the silos was used for the floor of the salt building. The 10-inch reinforced concrete surface provides an excellent base for storing salt. Well lit in its interior and exterior, the facility is secured at night but allows quick and convenient access to the salt supply when needed. The building also prevents salt loss from precipitation or runoff into surrounding lands, and the concrete pad reduces the potential for seepage into the ground.

A number of environmental improvements took place on the central and northern portions of the facility in relatively flat areas that were covered by bituminous drives and pavements. There are several below-grade structures located throughout the area that are associated with the defense facility that previously occupied the property. The storage facility is a slab-on-grade structure, utilizing precast concrete exterior panels.

Under-roof storage was only the first step in the Public Works Department's efforts in being environmentally responsible. Using salt efficiently is not only environmentally responsible, but goes a long way in controlling the cost of the Department's winter maintenance program. The Department uses 38 trucks of varied sizes to plow and salt the streets. In addition, the village hires 19 private contractors to plow 19 routes consisting of its 244 cul-de-sacs, 97 dead-end streets and 138 elbows.

The addition of the Salt Storage Facility will not only protect the environment, but will allow for the safe and efficient spreading of salt throughout the streets of the Village.


Monumental Entrance St. Louis Arch

Managing Agencies: St. Louis 2004; National Park Service

Primary Contractor: Alberici Constructors

Primary Consultant: HNTB Corporation

Nominated By: St. Louis 2004

The Jefferson National Expansion Memorial, the Gateway Arch, is the biggest tourist attraction in the St. Louis metropolitan area. The JNEM is also one of the most heavily visited urban parks in the National Park Service system. Over four million people a year visit the Arch and adjacent open space along the Mississippi River in downtown St. Louis, Missouri.

The Monumental Entrance project was the completion of a 40-year vision of the great architect Eero Saarinen, architect of the Gateway Arch and the Jefferson National Expansion Memorial completed in 1964. The architect's vision—the Monumental Entrance, designed to the grand scale of the Arch—would serve as amphitheatre seating for events and festivals along the riverfront.

The contractor started construction on December 1, 2002 and was required to be substantially complete by May 12, 2003 to meet the schedule of an international convention, which had scheduled an event on the existing steps of the Monumental Entrance. The construction proceeded into the winter of 2002-2003, with over 15 weather days lost due to snow, ice and frigid temperatures.

The contractor also had to address the issue of working on a steep slope to implement the pile driving, grade beam placement and precast riser/tread unit placement. All work with the overhead crane was required to be from the L.K. Sullivan Drive at the bottom of the steps due to the fact that the existing concrete pavement at the top of the steps could not support the heavy equipment without failing, and an active railroad line tunnel was immediately adjacent to the west of the project site.

The construction of the Monumental Entrance Amphitheatre did not impact the visitors' circulation or general experience of viewing the Gateway Arch and the river. During construction, the existing steps on both the north and south sides of the project were required to be kept open and accessible for visitors and citizens to the park. The high-profile project was subject to numerous reviews during construction by the local media who were cognizant of the impact the project would have for future events on the riverfront.

The Monumental Entrance Amphitheatre was and still is programmed to host numerous events for the Lewis and Clark Bicentennial in 2004. On March 14 the Three Flags Ceremony reenacted the exchanging of the Louisiana Purchase; representatives of the United States, France and Spain were present to participate in the ceremony. In addition, the St. Louis 2004 organization and numerous civic agencies will host celebrations during seven weekends during the summer of 2004.


Walt Disney Concert Hall

Managing Agency: Los Angeles County Department of Public Works

Primary Contractor: M.A. Mortenson, Inc.

Primary Consultant: Gehry Partners, LLP

Nominated By: Los Angeles County Chief Administrative Office

The Walt Disney Concert Hall, a world-class concert hall with state-of-the-art acoustics, is Los Angeles' newest architectural landmark and venue for classical music and the arts. It serves as the new home of the Los Angeles Philharmonic and the Los Angeles Master Chorale and is situated on a 3.6-acre site in the historic Bunker Hill section of Los Angeles. The facility has several performance areas within the site, including the 2,265-seat Walt Disney Concert Hall, the 250-seat Roy and Edna Disney CalArts Theater, the 300-seat Children's Amphitheatre, and a 120-seat reverse amphitheatre that has the stage and acoustical reflecting surfaces curved outward.

A seven-level subterranean parking structure provides 2,191 parking spaces for the 293,000-square-foot building. More than 12,500 pieces of primary steel, totaling 11,000 tons, were interconnected to form an intricate structure that serves as the framework to support the curving and graceful stainless steel exterior. Over 300 tons of bolts and weld were used to erect the structure and 275 tons of steel were used as temporary bracing for the walls, some of which lean out as much as 17 degrees. More than 60,000 cubic yards of concrete were used for the building and parking structure.

Skylights are constructed with three-inch-thick glass for sound attenuation. The exterior cladding system is made up of over 500,000 pieces including over 4,500 stainless steel panels covering approximately 180,000 square feet. An urban park is provided for public gathering surrounding the concert hall that features a colorful garden, walkways, benches and trees. The project cost was $363 million with the building cost alone at $274 million.

Many pioneering materials and methods were employed on this building including the stainless steel exterior skin with individual removable panels, a separate internal waterproof barrier, and a cleaning system supported from the roof that works with the unusual exterior surface geometry. Soft wood on the performance stage and other finishes inside the hall were used to deliver clear and vibrant sound to the audience. In addition, acoustic/structural isolation was provided between performance venues/practice rooms and other uses in the facility, and through the use of a massive concrete roof and upper walls around the performance hall. These concrete elements allow for full theatrical digital sound scoring to take place within the performance hall even with a helicopter hovering just above.

The Walt Disney Concert Hall has met the community's expectation that it would serve as the defining civic improvement to fully establish Los Angeles as an international destination for enjoyment of architecture and the arts.


Cliffdale Road Bridge Reconstruction Project

Managing Agency: Town of Greenwich, Connecticut, Department of Public Works, Engineering Division

Primary Contractor: New England Road, Inc. (NERI)

Primary Consultant: Dewberry-Goodkind, Inc.

Nominated By: APWA New England Chapter

The Cliffdale Road Bridge Reconstruction Project in the Town of Greenwich proved to be a clinic in public works tasks and challenges. The Department of Public Works-Engineering Division was required to interact with the public, to solicit support from residents and property owners, to obtain local planning and zoning permits, and to obtain state and local environmental permits, all of which required significant time and extensive documentation. The Engineering Division was also required to obtain federal and state funding, which required state and local agreements for all phases of work, additional design procedures and standards, additional specifications and federal mandates, and more extensive environmental permits and requirements.

Several unforeseen conditions were encountered during construction that presented challenges for the Town, its consultant and the contractor. The deep ravine and the steep slopes approaching the site did not allow for storage of materials or equipment. Closing the roadway allowed only limited work areas on both sides. Because the roadway on the west side of the bridge sloped upward to a grade of 15 percent within 100 feet of the bridge, all excavated rock, earth, and stone masonry materials had to be stored at a Town facility 10 miles from the site. Approximately 1,500 cubic yards of material were removed and 900 cubic yards brought back for the formation of embankments and the construction of riprap slopes.

Numerous special provisions and operations to protect the natural environment in this rural area of the community were included in this project. Temporary sheeting isolating all foundation excavations from the river was required. Water pumping discharges from the deep excavations were directed to a prefabricated steel settling tank set adjacent to the work. In addition, the discharge from the settling tank was directed to the inside of the temporary sheeting to allow infiltration back into the groundwater. The project plans also defined a "limited" area of disturbance, so that activities near the stream and sensitive wetland areas were controlled. Extensive placement of erosion and sediment control measures were required to protect the river as part of the requirements of the local IWWA permit.

The aesthetics of the new bridge was a primary concern of the local residents and the community. The Engineering Division and the consultant were charged with the task of developing a bridge design that was compatible with the rural and scenic nature of this unique area of the community. Working closely with residents, the Town was able to develop a "context sensitive design" that met all minimum design standards, as well as residents' concerns.


Germantown Avenue Bridge over the Wissahickon Creek

Managing Agency: City of Philadelphia Department of Streets, Bridge Section

Primary Contractor: Neshaminy Constructors, Inc.

Primary Consultant: URS Corporation, Inc.

Nominated By: APWA Delaware Valley Chapter

The Germantown Avenue Bridge serves as an arterial route connecting the Chestnut Hill section of the City of Philadelphia with its neighboring communities to the northwest. The previous bridge consisted of nine spans on eight stone piers with a total length of 214 feet. The massive stone piers dated back to 1786, and the existing superstructure was reconstructed in 1920. The structure carries approximately 13,400 vehicles a day and also serves as a vital link to the Chestnut Hill College located adjacent to the bridge.

The project included construction of a three-span 313' (98'-116'-99') continuous curved girder highway bridge, a three-span 275' (70'-109'-96') variable width pedestrian bridge, and a half-mile of 36' wide roadway including 5' bike lands, 11' travel lanes, and a 4' Belgian Block median. Also included were extensive adjustments to the college driveway, stream bank restoration, landscaping, and architectural enhancements.

The length of the contract was set at 330 days. The schedule was aggressive in order to limit the impact of the bridge closure on the community. The removal of the bridge created a circuitous detour. The impact on emergency vehicles to Chestnut Hill College was of particular concern. The community also desired to have the closure restricted to one Christmas shopping season to limit the economic impact on the local business district.

Because detoured traffic would be forced to use the limited existing roadway system, new signals were installed at key intersections and provisions for timing adjustments were made to help alleviate the impact of the detour. The route experienced some minor delays and complaints in the first few weeks of the project, so the engineers initiated more traffic signals timing adjustments. Drivers quickly adjusted to the detour and delays were minimized to the best possible extent.

Most of the substructure construction occurred in the winter months, which is usually the ideal time of the year to complete a 330-day bridge construction project. All winter concrete was cured with proper cold weather protection precautions as per PennDOT construction specifications. When springtime arrived, the contractor simultaneously performed work on bridge items as well as roadway approach items to bring the opening of both the bridge and roadway to vehicular traffic to fruition as quickly as possible.

The concrete bridge deck was placed in August, and concrete temperatures were monitored to ensure the delivered concrete was cooled below the maximum temperature allowed by specification. Admixtures such as superplasticizers and polypropylene fibers were included in the mix design to assist in concrete crack control. Concrete pumping was utilized to obtain a fast rate of placement during the 90ยง air temperatures.

The contractor's safety program resulted in an accident-free project.


South 180th Street Grade Separation Project

Managing Agency: City of Tukwila, Washington

Primary Contractor: Wilder Construction

Primary Consultant: BERGER/ABAM Engineers Inc.

Nominated By: APWA Washington Chapter

The Southcenter retail area of Tukwila and Renton is blessed with some of Seattle's biggest retailers like IKEA, Costco, Southcenter Mall, and Parkway Supercenter. Shoppers and employees get to these stores on South 180th Street, a four-lane arterial through Tukwila, Renton, and Kent. Or rather, until recently, they tried to get to their destination using South 180th Street. About 60 times every day, freight and passenger trains crossed the road and brought cars to a halt, often for more than 15 minutes at a time. More than 40,000 drivers were delayed daily, and thus the City of Tukwila had to do something to separate railroad and vehicular traffic.

An overpass? Too expensive, too many displaced and access-impacted businesses, and an eyesore. An underpass? Less costly, less business impacts, less of a visual impact, but very problematic. With poor soils, a stream, and a water table only five feet beneath the surface, the site basically sat on top of an underground lake. Space for roadway expansion was cramped, a wetland existed between the two sets of train tracks, and a historic house lay in the way.

The City opted for the underpass, also described as a grade separation, and challenged the consultant to make it work. The solution included both technical and tactical approaches featuring the following items:

  • Cement Deep Soil Mixing (CDSM) Seal—the first-known application of this technology for a permanent roadway groundwater seal in the United States, adding concrete slurry to native soils, strengthening them to prevent water penetration through the bottom of the grade separation.
  • Secant Pile Walls—drilling continuously interlocking cylinders 60 feet deep into alluvial soils and filling them with concrete to create the side walls of the underpass and to support the railroad and pedestrian bridges over the grade separation. The CDSM bottom seal and secant pile side walls combine to create a structure much like the impervious hull of a boat.
  • Strategic rerouting of cars and trucks to a new street built nearby by the City of Kent, cutting about 1.5 years off the initial project schedule.
  • Railroad diversion over three temporary lanes of track, preventing disruption of traffic.

Considerable effort went into the specification for the CDSM work to ensure the technique was the right solution for this site. In the end, that work paid off handsomely as most of the gain in schedule (the grade separation was opened to traffic 58 days ahead of schedule) was accomplished by quicker than expected CDSM construction while still meeting the specification for CDSM performance.