Allies’ forces

Nov. 18, 2009

The Boulevard of the Allies and Forbes Avenue are two major arteries in the western Pennsylvania region. They connect the city of Pittsburgh’s downtown area, a vibrant urban neighborhood, with Oakland, a regional center for culture, higher education and health care.

The Boulevard of the Allies and Forbes Avenue are two major arteries in the western Pennsylvania region. They connect the city of Pittsburgh’s downtown area, a vibrant urban neighborhood, with Oakland, a regional center for culture, higher education and health care.

The Boulevard of the Allies is a four-lane divided arterial, which traverses a bluff overlooking the Monongahela River valley. Paralleling the boulevard one block to the south is Forbes Avenue. As the parallel roadways approach Oakland, Forbes Avenue turns north and enters the heart of Oakland, while the Boulevard of the Allies continues east, bridging over Forbes Avenue. The physical configuration of the Allies Bridge spanning Forbes Avenue creates a high-profile and well-traveled corridor referred to as the “Gateway to Oakland.”

The gateway was in dire need of rehabilitation. The universities were reluctant to bring new recruits through the corridor due to the unattractive and unsafe appearance of the bridges and the dilapidated atmosphere of the area. The areas adjacent to the bridge include local merchants, small office buildings and the Oakcliff residential neighborhood. The proximity to local neighborhoods makes the quality of life an important consideration in the project’s design.

The bridges were built in the early 1920s as part of the Boulevard of the Allies, an inner-city boulevard dedicated to the veterans of World War I. The intent of the original road project was to adorn the boulevard with stately architectural designs and memorials. However, these adornments and their physical condition were not enough to warrant historical designation for the Boulevard of the Allies or its bridges.

Everybody has needs

The project included replacing the severely deteriorated main span Boulevard of the Allies bridge and the two ramp structures (one being load posted for 9 tons); improving existing traffic patterns; addressing traffic safety issues, such as inadequate sight distance at the existing ramp structures; and improving the substandard geometric configuration of the structures.

In the late 1990s, the Pennsylvania Department of Transportation (PennDOT) performed an alternative analysis of the project area to determine the best configuration of ramps and bridges that would serve the needs of the communities well into the future.

The analysis determined that the mainline bridge and the off-ramp bridge should be replaced in the same location and that the on-ramp bridge should be removed and replaced with a new on-ramp from Fifth Avenue to the boulevard, eliminating one structure.

In 2000, as a response to stakeholder concerns about the aesthetics of the area and the proposed new bridges, PennDOT initiated an open, contextual design process to respond to the needs and aspirations of the Oakland community, which was calling for a signature gateway design for the bridges.

The priorities for the final design concept of the bridges varied widely across the various stakeholder groups involved in the planning process. PennDOT needed to replace three deteriorating bridges and improve circulation in the area. The Oakland institutions (universities, hospitals and cultural organizations) wanted a gateway design through which they could be proud to transport prospective students and faculty as well as visiting VIPs.

The community wanted to correct traffic circulation problems caused by the current bridge’s ramp configuration and enhance access to adjacent development sites and residential neighborhoods. The overall goal was to provide an affordable, functional and safe bridge that also would address concerns of a context-sensitive design.

Picking up the pieces

Bridge projects are initiated for a reason; they are needed and, in many cases, needed yesterday. The longer the design process takes, the longer the need goes unaddressed and, through inflation and continued deterioration, the more expensive the project becomes. All of these factors led to a need for an expeditious design process. Unfortunately, context-sensitive design slows the process by interjecting new elements for consideration and negotiation.

The bridges were a growing maintenance problem requiring extraordinary maintenance measures (such as encasing the steel piers in concrete) and a growing liability concern as pieces of the structure began falling onto the roadway below.

The kick-off of the final design process included a design charette with members of PennDOT, the design engineering team and members of the large CDAT. Based on this meeting, several basic elements were added to the design that were not in the original design. The elements included arch-style beams, enhanced landscaping, sidewalks, additional aesthetic elements, smaller-scale lighting and more.

A vertical shot

At the time of the final design process, it was reported that over 30% of the Pittsburgh-area bridges were categorized as structurally deficient, and the district was under pressure to ensure that the available funds were stretched to meet all the needs of the region, not focused on this one project.

In order to create an aesthetically pleasing structure while staying within the budget, compromise became the key concept that would describe the process that occurred for the next couple of years. The smaller boulevard CDAT group started to meet more often to hammer out the more intimate details of the project.

After the district agreed upon a steel-arched superstructure, the group focused on the other aspects of the project. Architect Paul Tellers from Carnegie Mellon was instrumental in depicting a vision for the gateway. Tellers envisioned vertical components that would accentuate the arched girders while providing prominent structural features on the top of the bridge.

In order to achieve the verticality, it was suggested that pilasters be erected on top of the bridge at the four corners and to adorn the abutments with vertical concrete accents under the beams.

The CDAT group also wanted to preserve the architectural features of the existing bridge as much as possible to perpetuate the tribute to the Boulevard of the Allies. The existing bridge was adorned with large metal eagles and commemorative plaques, which could not be salvaged. The group focused on replacing the old metal emblems with a larger concrete eagle. The determination of the type, size and location of the commemorative eagles was a long and arduous process that culminated in the placement of an 8- x 8-ft precast concrete eagle on the abutment wingwalls.

Other details were discussed and agreed upon throughout this collaborative process. It was determined that the street lighting would be the city of Pittsburgh decorative lighting standard, which is used throughout the city on their enhancement projects. The Department of City Planning did not want to use standard guide rail or jersey barrier on the project, so the recently approved PA barrier was used to preserve the view from the bridge.

Lastly, the CDAT group requested landscaping beyond the normal seeding of a PennDOT project. The CDAT stepped forward on the issue to provide the design fee for the landscaping designs.

The resulting landscape design was still very costly due to the large area encompassed in the design and the costs associated with the large number and types of plantings.

The group had concerns that without a proper irrigation system, the plants would fail in the first year. The CDAT group solicited the philanthropic organizations in the city and obtained a grant to pay $200,000 toward the plants and irrigation system.

With the engineering drawings ready for bid and the challenges of the context-sensitive design process behind them, the design team set out to estimate a final construction cost.

Slipping in a ramp

After the final design process was completed in 2005, the project was prepared for bid. The construction cost estimate developed by the design team was approximately $26 million. Limited resources and a burgeoning need required PennDOT to take a serious look at ways of reducing the cost of the project. The engineers proposed the removal of the off-ramp bridge structure and replacing it with a slip ramp to Forbes Avenue. This change would reduce project costs by an estimated $4.83 million.

Given the significance of removing the off-ramp span, the community was re-engaged through public meetings to determine what additional impacts would need to be addressed. The resulting impacts were significant enough to reconvene the CDAT group. The neighborhood cut-through traffic was a major issue that was discussed. The engineers developed a traffic plan that was amicable to PennDOT as well as the community and business groups. The plan consisted of closing some local street access.

The group anticipated that bus routing through the area would be a major concern. In actuality, the Port Authority of Allegheny County (PAAC) became an ally in this redesign concept. As part of the new roadway configuration, the PAAC suggested some minor improvements to the Craft and Boulevard intersection, which would create an improved routing system than exists today.

The new slip-ramp design incorporated a significant retaining wall along Forbes Avenue to support the boulevard. The aesthetics of the new wall became a significant hurdle to overcome. The CDAT did not want a large concrete wall marring their gateway and worked with the department and the engineer to develop a design that would maintain the verticality so desired in the project. To facilitate their desires, the engineers adjusted required spacing of the soldier beams to allow the joints to match the PA barrier joints on the boulevard above.

After all the issues were addressed to the satisfaction of the stakeholders, Wilbur Smith and Associates completed the final design of the project. With this consensus in hand, the total right-sized cost estimate for the project, including both hard and soft costs, was $21 million.

The eagles stay

The project was put out for bid in the fall of 2006 during a period when project costs were skyrocketing for PennDOT and public agencies due to rising fuel costs, increasing material costs, etc. The high bids were traced back to price-history data that was inconsistent with the current market and the relative inexperience of the bridge and roadway contractors, with large precast elements being attached to a bridge structure.

The department reviewed all options: Should we rebid? Can we change the design? Do we have time to change the design and get it back out to bid quickly? Will a redesign change it enough to make it affordable under the current budget? After many discussions with the district, central office and the chief engineer it was determined that the most effective way to proceed was to re-evaluate the proposed wall designs and aesthetic features to create a bid proposal that would allow contract creativity and hopefully lower bids.

The CDAT members were reconvened to review the potential revised designs. The proposed concrete median barriers were simplified from a chamfered design to a plain straight-faced barrier. The eagle and framing panels also were simplified, but they remained because the CDAT group considered this to be the most important aesthetic feature of the project. The pilasters did not survive the value-engineering process because of their high costs.

The project was rebid on Feb. 1, 2007, and the low bid was $29,109,868, which was still more than the original budget but a few million less than the original bid opening. The successful contractor was Joseph B. Fay Co. The savings were realized from the reduction of aesthetic elements and the institution of the design-build concept for the wall and wing- wall elements.

The construction of the project also was a challenge due to the high traffic volumes and limited space around the structure for construction activities. The contractor was required to maintain traffic flow through the site to the major universities and hospitals within the Oakland area.

To help alleviate these concerns, PennDOT and the Oakland Transportation Management Association (OTMA) provided an extensive public outreach campaign that included large posters and newsletters to the institutions to be displayed and distributed in prominent areas in the hospitals, as well as in the universities. The newsletters were published several times throughout the construction when significant changes to the traffic phasing were implemented.

Additionally, the OTMA, in close collaboration with PennDOT, instituted an e-mail notification system to alert drivers and concerned shareholders of current construction status and of upcoming changes to traffic phases with dates and times.

The project, which is now complete, provides a structure that serves as a revitalized “Gateway to Oakland” while meeting the functional needs of the institutions and the community in the Oakland area.

About The Author: Moon-Sirianni is the assistant district executive for design for PennDOT, District 11. Pintar is vice president for Wilbur Smith Associates, Pittsburgh. Hassett is assistant director for the city of Pittsburgh, Department of Public Works.

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