The Haight-Ashbury district, the Golden Gate Bridge, Alcatraz — San Francisco residents can be mighty protective of their historical landmarks and scenic views.
That’s something planning and engineering company Parsons Brinckerhoff (PB) discovered when it sought to win the contract for the reconstruction of the city’s Doyle Drive which was opened in 1936.
The $1.05 billion mega project included building a replacement for the south access to the Golden Gate Bridge with a new Presidio Parkway.
“You only need to mention the words Presidio and Parkway together to raise the concern of residents about the preservation of this historic military outpost,” remarked Phil Bernstein, vice-president, industry strategy at Autodesk Inc. of San Rafael, Calif.
“People were worried that a highway would be driven right through the Presidio.”
New York-based Parsons Brinckerhoff, however, used the power of 3D simulation to “tell the story” of how a new parkway-type facility, which includes short tunnels and accesses, would have little to no impact on the natural environment, cultural and community resources, and the Presidio.
Out with the old, in with the new
The Doyle Drive currently handles 144,000 persons traveling each weekday.
“But the highway — built in the 1930s — has reached its end-of-life stage,” said Art Schintzel, senior building manager at PB.
Schintzel was a keynote speaker at the Autodesk University conference held in Las Vegas last week.
Doyle Drive is a direct route from San Francisco’s Marina District and Palace of the Fine Arts, through the Presidio, to the bridge toll plaza.
The original road has outlasted its useful lifespan with respect to traffic capacity, seismic resistance, and overall roadway conditions, said the PB manager.
At least 80 per cent of the current structure cannot be suitably retrofitted, so replacement is the only option.
The new Presidio parkway, on which construction was started last month, is expected to be safer for drivers — offering wider, 11-foot lanes, a median barrier, and road shoulders. The Parkway is scheduled to open by 2013.
The new parkway is also likely to do a better job of slowing traffic down as it enters the Marina District’s streets.
From a close-to-the-public military outpost, the Presidio, in which both the existing drive and proposed parkway are located, is now a major community destination and tourist attraction that’s part of the Golden Gate National Recreation Area.
PB executives said their company wanted to assure the public itis creating a roadway that respects the national park, the National Historic Landmark District, and surrounding neighborhoods.
Another big challenge is how to keep the numerous professionals from various disciplines — mechanical engineers, civil engineers, electrical engineers and architects, hundreds of trades and thousands of workers — updated on developments relating to each project phase that concerns them, said Schintzel.
The project client — the California Department of Transportation (Caltrans) — is also doing the roadway design, while a joint-venture between consultants PB and Arup, a London-based design and engineering firm, is handling the environmental and architectural aspects of the project as well as project communications.
“This project couldn’t go through without the collaboration capabilities offered by Autodesk tools,” said Schintzel.
PB aggregated data from 2D CAD (computer aided design) files and sheet files into 3D models.
Access to a holistic view of the project eliminates the need for costly changes later on in the game when they would become more expensive.
This process, Schintzel said, enabled PB to provide valuable design-stage feedback to Caltrans without forcing the client to change its established internal 2D workflow.
Visualizations were also created to study architectural elements, such as retaining walls, signage, and landscaping at the tunnel portals, where the proposed parkway will burrow under, rather than cut through, the Presidio environment.
A “story-telling” video
Using Autodesk tools, typically employed for video game and animation projects, stakeholders and residents were presented with a “story telling” video that offers a birds-eye-view of the whole project as it relates to the San Francisco Bay Area landscape.
The video shows how the old roadway will be transformed by the Presidio Parkway, and how potential infrastructural eyesores will be prevented by constructing short tunnels covered by greenery.
The viewer is then treated to a “drive” along the Parkway at street-level where they can see how vehicles will merge into or leave the proposed road and how traffic will flow through the neighbourhood.
In the end the 3D drive-through proved pivotal in driving home the message that the proposed parkway would burrow under, rather than cut through the beloved Presidio landscape.