Monday, March 01, 2010

SW-SE Freeway Burial

Burying the SW-SE Freeway: or more accurately remove and replace the existing almost entirely elevated freeway with an underground covered freeway.

Illustration: 1993 NCPC SW-SE Freeway Tunnel

A idea needed yet continually delayed and botched

The idea of burying the SW-SE Freeway is one long considered, though apparently with little in depth engineering studies, with segments developed piecemeal, without a design tying them together.

The idea appears in the U.S. National Capital Planning Commission’s planning, as reported by the Washington Post in 1993, from Water Street SW to 7th Street SE, together with burying the railroads and restoring surface roads as F Street, Maryland and Virginia Avenues, along with reconstructing the major bridges.

U.S. NCPC's Extending the Legacy: Planning America's Capital for the 21st Century with the unnamed 'South Capitol Mall' on the cover

It disappears in the subsequent “Extending the Legacy: Planning America’s Capital for the 21st Century”, which retains the idea of reconstructing the railroads, along with a freeway system becoming even less continuous via a ‘proposed road network’ that -- while covering portions of the existing I-66 West Leg by the JFK Center, and reconstructing and covering portions of the Anacostia Freeway -- becomes more disjointed by eliminating the SW-SE Freeway, substituting instead the local street grid with the addition of a parallel cross Potomac Tunnel from Virginia to M Street SW.

This plan routes the new replacement for the existing jumble of 14th Street Bridges to a traffic light intersection at the intersection of 14th Street and a restored F Street SW to a small set of ramp portals to a Center Leg (3rd Street Tunnel), just before the top of what was to be a grand new “Mall” along a widened South Capitol Street, with the SE Freeway replaced by a surface Virginia Avenue, and with the railroad to the west replaced or covered with a restored Maryland Avenue.

1996 NCPC 14th Street Bridge to E Street

1996 NCPC E Street Ramp to I-395

The reality of the traffic feeding into this I-395 SW Freeway via the 14th Street Bridges from the I-395 Shirley Highway, Routes 27 and 1 as well as the George Washington Parkway makes this idea impractical.

This reality was acknowledged such subsequent work as the following year 2000 presentation at the National Building Museum by Joseph Passonneau to bury the SE Freeway and the adjoining railroad along Virginia Avenue SE, from South Capitol Street to the approaches to the 11th Street Bridge, and with the SE segment further east converted into a boulevard. Although focusing upon the SE Freeway, Passoneau’s lecture would give lip service to the idea of decking over the currently depressed segment of the SE Freeway just west of 7th Street SW.

Passoneau’s proposal was done without any apparent engineering considerations for the connections between this proposal for a SE Freeway Tunnel that somehow met the existing elevated grade of the SW Freeway.

West Portal of Joseph Passoneau’s SE Freeway Tunnel Proposal
at South Capitol Street

West Portal of Joseph Passoneau’s SE Freeway Tunnel Proposal

SE Freeway – existing; Passonneau ‘tunnel’ illustration simply a ‘photoshoped’ lid atop the existing elevated freeway

Constructing a lid atop the existing elevated SE Freeway would require raising the elevation of South Capitol Street to radically affect its relationship with the buildings to the south- eg. placing at least the 1st story of the buildings alongside South Capitol Street below street level.

Note the SE Freeway’s transition from elevated berm to open viaduct in order to cross the mouth of the Virginia Avenue Tunnel.

I was disappointed to see no illustrations of this freeway being lowered before being covered, nor any of how the under grounded freeway and railway roadways would be configured. Given their proximities and grade requirements – freeways can tolerate 5-7 % while heavy rail can only take 1% -- and the short distances to the 11th Street Bridges – the under-grounding of the SE Freeway is surely a project to coordinate with that for reconstructing the railway, such as that now announced to start construction by 2011.

Passoneau’s undeveloped central section for the SW-SE Freeway reflects the apparent lack of any officially commissioned engineering study. With the SW-SE Freeway transition an elevated viaduct, there’s far more work involved then simply placing a lid atop an existing road, with this segment involving all new underground roadways that would connect to an existing roadway near 7th Street SW. AFAIK there has been no official study upon this area of the SW-SE Freeway, despite all of the lip service given to opening up the South Capitol Street vista.

Although alongside, and shown in the median of the Passonneau tunnel cross-section, there’s been no apparent planning coordination regarding any lowering-covering of the SE Freeway (and by default eastern SW Freeway) with the Virginia Avenue Railroad tunnel due to start construction by 2012.

Instead, through their actions and inactions, the authorities would ‘cement’ or literally lock in the status quo extending its life while thwart under-grounding.

In 1996-2001, the Federal government would spend millions of $ reconstructing the SW-SE Freeway in its existing configuration, with the addition of an auxiliary ramp from the northbound 11th Street Bridge along the SE Freeway to the ramp to the Center Leg (3rd Street Tunnel). This extends its lifespan by at least 40 years and thus likely to push its under-grounding into a more distant future.

Nearly simultaneously, authorities would allow real estate development to further encroach upon land immediately adjacent to the SW Freeway that was cleared of buildings and critical for facilitating the freeway’s lowering and covering while maintaining traffic (to say nothing of that immediately adjacent as a temporary construction staging site reducing construction vehicle traffic upon local streets).

The entire strip along the SW Freeway’s southern side was entirely cleared of buildings as a part of the SW ‘Urban Renewal’, with the westernmost segment occupied by the new Banecker Overlook, and by the early 1970s further east all developed with buildings placed as close as 70 or so feet from the freeway’s southern edge.

Given that the land along the southern side of the SW Freeway was cleared anyway as part of the late 1950s early 1960s SW Urban ‘Renewal’ , why was not the freeway located say a half block or more to the south, giving a gentler turning radii for its connections with the Center Leg gentler turning radii and even, if placed either south of G Street, or as a tunnel beneath, avoid blocking the local east-west vista to and from the Jefferson Memorial.

Such real estate development directly impacted the idea of covering the existing SW Freeway between 7th and 9th Streets SW by the 1999 construction of the strip of 28 townhouses built as the northernmost edge of the Capital Square project. These townhouses, a mere 16 ½ feet from the SW Freeway’s southern side retaining wall that was not designed to support a tunnel roof and hence need to be replaced, complicate the tunnelization, thanks to EYA Associates choosing to place them so close to the SW Freeway, simply asking for a future situation where their dwellings inhabitants are surprised by the proximity of their townhouses to the new construction- sort of as how some further east along Virginia Avenue SE may be regarding the railroad project. Beyond complicating the SW Freeway tunnelization, the meager 16 1/5 foot setback creates a route construction, with the buildings further east being some 70 feet or more away, with regional implications regarding traffic congestion at a spot segment significantly necked down – with its planned South Leg and I-95 14th Street Bridges, each with 6 lanes, feeding into a 10 lane SW Freeway with mere 2 lane connectors for the SW Freeway I-95 Center Leg interchange.

Illustration: SW Freeway close up

Note the various ramp connections, with this line illustration before the addition of the EYI Capital Square townhouse project

A roughly concurrent and subsequently discarded proposal for a new museum to the west would continue this mere 16 ½ setback promoted by the ‘Committee of 100 on the Federal City’ and its spin-off organization ‘Save the Mall’ would be rejected by 2006.

That EYA was able to secure approval for this project, and that planning authorities failed to preserve a strip or band of land along the southern side of the SW Freeway stands as mute testimony of the failure of official planning, along with such neighboring entities here as the U.S. Departments of Housing & Urban Development, and of Transportation.

Illustration: overhead of area with USHUD and USDOT across from the EYI/Capital Square pinch of the SW Freeway corridor

Such a juxtaposition attests to the need for major real estate development projects to be allowed to proceed after an evaluation within an environmental impact statement upon how they would effect the costs of foreseeable future transportation corridor upgrades, such as with an improved underground SW-SE Freeway replacement- for instance the “Capital Square” property would have made an idea construction staging area for the SW-SE Freeway burial requiring far fewer truck trips upon local streets owing to its adjacent location.

U.S. NCPC, which embraced the idea of a buried SW Freeway in 1993 only to ‘forget’ it in 1996-97, has since reversed itself with its 2008 proposal extending this idea further west with its proposal for an all new “14th Street Bridge” including an I-395 Washington Chanel Tunnel. This would replace the existing Washington Channel Bridge which now carries I-395.

Illustrations: 2008 USNCPC

This would reconfigure the 9th and 12th Street connectors, reversing their current directions.

The basic tunnel alignment -- upon the extended axis of Louisiana Avenue – is virtually the same as where my studies led- though without my idea of extending G Street west via fill towards the Jefferson Memorial.

However, apparently only for an apparently unnecessary (given the elevations) to avoid going beneath the Bannecker grassy knoll, the 2008 NCPC design has a sharper curved transition onto the existing SW Freeway right of way. It does not displace that northernmost row of Capital Square townhouses, hence staying entirely within the existing right of way.

As with previous NCPC proposals, this 2008 initiative includes a redesign of the nearby railroad.

Likewise it includes a recreation of the surface street grid.

Alas the proposal fails to go further in showing how the re-design of the SW-SE Freeway center section with its connections to the Center Leg (3rd Street Tunnel) and the South Capitol Street corridor, while hobbling it with the constraint that it displace 0 buildings- indicated by the preservation of the northernmost row of EYI Capital Square townhouses.

Note the ‘Capitol Square’ location’s appearance here as an empty field- which would have been ideal as a staging area for a construction project to bury the SW Freeway , yet an irresponsible government would not even purchase its northernmost strip necessary for the start of a new parallel lowered roadway

Such a constraint against parallel construction, particularly where the new Washington Channel Tunnel meets the portion of the existing SW Freeway that would not simply be covered but replaced with its mainline lowered, would make the NCPC design relatively difficult to construct while maintaining traffic. AFIAK, this is unmentioned in the NCPC text, as are any such parallel construction ideas as starting the SW Freeway cut and cover reconstruction directly along the southern side of a right of way widening displacing the 28 foolishly placed EYA townhouses, and that of a parallel tunnel beneath G Street to SE, connecting to a Center Leg augmented with parallel tunnels beneath 2nd and 3rd Streets NW/SW.

Such parallel construction would make the under-grounding of the SW-SE Freeway and its interchange with the Center Leg (3rd Street Tunnel) infinitely more practical, while providing the capacity for eliminating the need for 2 into 1 lane merges that would otherwise come with the added capacity and links, such as officially proposed South Capital Street corridor tunnel that would essentially provide a direct southern extension of the Center Leg (3rd Street Tunnel), along with a 1996+ D.C. government proposal for a northern extension via a new tunnel beneath New York Avenue.

Because of these highway segment’s proximity, they need to be planned together- something which really is not very apparent from any of the studies. Though each study naturally is focused upon a specific corridor, the broader based studies nonetheless behave all fearful of the idea of daring to plan a more continuous and contiguous freeway system- regardless of the types of designs. Although encased tunnel designs could provide the express routes while blocking the noise and pollution, government planning remains beholden to a strictly anti-freeway doctrine that subverts livability in so many ways (yet remains useful for other political purposes).

Illustrations: 1996+ New York Avenue Tunnel; 2003 DCDOT SCST- 2 options;

This sort of fear of from the top of the political pyramid has effectively thwarted both the New York Avenue and South Capital Street corridor tunneled motorways.

The New York Avenue Tunnel as proposed since the so-called ‘Ron Linton’ plan of 1996, is beholden to a ‘golden rule’ that it may not displace a single dwelling (a standard adhered to by Washington D.C. for NOTHING else), hobbling it with deficient geometry with a transition radii from the existing I-395 right of way to beneath New York Avenue of under 500 feet, when USFHWA rules state that a curved tunnel’s radii should be no less than 850 feet. It is understandable that they do not want to revive the previous design of the 1970s that had a somewhat better radii but displaced 600+ dwellings in a band paralleling the northern side of New York Avenue between 3rd Street NW and 1st Street NE. Yet the option of the idea of an even better radii tunnel to the north passing beneath the intersection of New Jersey Avenue and N Street and then the recreation field of Dunbar HS and O Street, displacing as few as 33 dwellings remains officially unconsidered.

For ‘reasoning’ that places all of this beholden to a parochialist ideology, its planning is further in doubt, as expressed by the USNCPC ‘Charate’ – or more appropriately ‘charade’ on the New York Avenue corridor planning which concludes that the tunnel should not be built because it would benefit too many groups of people. It is a sentiment that has deeply infected the planning of Washington DC, that it should serve fewer people, leading to the cancellation of ALL of the remaining major freeway links including those that had already been redesigned as significant tunnels all for an ideology that assumed that a manmade oil shortage – it was after all the OPEC oil embargo – mean that nothing could replace petroleum and hence since we would soon run out, that private autos would be an obsolete concept by the 1990s. It is furthermore evident, not only with the above mentioned fearfulness, but via such predictions from USNCPC documents, as this from ‘Extending the Legacy- Planning America’s Capital for the 21st Century', that bridges will be made obsolete by amphibious automobiles.

The South Capitol Tunnel has continued to receive some lip service since being put off by the 2004 Urban Land Institute, even as the refusal to move the St Vincent de Paul Roman Catholic Church, the construction immediately to the east with the 20 M Street Building, and to the south with ‘Nationals Ballpark Stadium’ opened in March 2008, has effectively blocked the east-parallel option. Though it could conceivably still be constructed directly beneath South Capitol Street at greater expense, I have not found any indication of any planning reservations for any sort of ramp access from encroachment by the real estate development being enthusiastically pursued along South Capitol Street.

The idea of burying the SW-SE Freeway, particularly with its apparent inevitability with the continuing existence of the 11th Street Bridges further extended with the recently started replacement project, is politically popular enough to appear within official planning documents now cited by residents concerned about the impending CSX National Gateway Virginia Avenue RR Tunnel project.

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