Saturday, April 9, 2016

Sheridan Expressway 'Boulevardization' Persists

Rejected in 2012, the idea of eliminating the Sheridan Expressway grade separation continues, with NY officials earmarking $97 million for removal, with a new report recommending that its northern, at grade segment be converted to a traffic light signalized boulevard, upon a reduced right of way.

Option #3 with right of way reduced to 115 feet
Orange marked cross streets, from bottom: Jennings, 172nd and 173rd Streets

This report displays a number of options for this segment, including narrowing the existing 210 foot building line to building line right of way to as little as 115 feet to facilitate greater amount of real estate square footage to the east.

Option #1 Retain existing 210 foot right of way with flanking service roads
Option #2 Modify-Separated 155 foot right of way, eliminated the eastern service road
Option #3 Modify-Combined 115 foot right of way, eliminates both service road

All of these options would transform the existing surface Sheridan Expressway into a traffic light signalized Boulevard.

Option #3 would essentially require demolishing the recently reconstructed Sheridan roadbed, in order to squeeze it to the west, displacing a separate West Farms Drive.

note that this is in the side of a hill.

Existing Sheridan profile looking north

Advocates for removing the Sheridan Expressway cite improved waterfront access and development, and reduced vehicular pollution as reasons.

But is adding traffic light intersections to what is now a grade separated express highway corridor, that is still fed by freeway segments at both ends between the highly used Cross Bronx Expressway and the Hunts Point Truck Depot really the best solution?

Previous calls for entirely removing the Sheridan Expressway were rejected with the finds that eliminating its grade separated "below grade" under-passing of Westchester Avenue would drastically increase traffic congestion and pollution at the alternative parallel route of the traffic light intersection of Westchester Avenue with Whitlock Avenue.  Meanwhile removing the Sheridan Expressway's "above grade" elevated portion to the south would transfer the traffic further along Whitlock, while doing nothing to address the parallel elevated 'subway' and surface railroad that now flank it and also separate the area from the waterfront.

1st stage of Northern Sheridan Area Re-development

Hence, the planning discussions now focus upon the Sheridan's northern segment.

Except for its transition to its underpass crossing of Westchester Avenue, this segment runs "at grade" along the surface.

And this focus is exclusively upon the idea of converting this Sheridan segment into a boulevard, equipped with three new traffic light intersections, one apiece for the crossings of Jennings Street, 172, and 173rd Streets, and flanked by rows of new buildings.

To the north, the existing grade separation beneath the 174th Street Bridge would be retained, along with the ramp connects to and from the Cross Bronx Expressway.

And to the south would remain the existing Sheridan Expressway, with its underpass crossing below Westchester Avenue, and further south with its elevated viaduct wedged between the railroad to the east, and the elevated 'subway' line to the west, feeding directly into the elevated segment of the Bruckner Expressway, which would have a new set of ramps to Hunts Point Market to better facilitate truck traffic.

And flanking this "Boulevardized" Sheridan segment, new rows of buildings to the west, where the topography rises as a hill, and to the east where it runs flat towards the Bronx River, would replace existing industrial uses and contain hundreds of new residential dwellings.

All of this is being touted as the best option to improving the urban landscape with new park-lands, neighborhoods and jobs, with significantly improved local access to the Bronx River waterfront.


New development facing the lower portion of the Bronx River with enlarged parkland and improved local pedestrian access are all laudable goals, even though displacing industrial uses which could nonetheless be relocated to perhaps Hunts Point.

But how honest is it to combine this with the idea of replacing this surface segment of the Sheridan Expressway with a "boulevard" with three new traffic light intersections, and to issue renderings showing that with 1,000 plus new residential dwellings and presumably far more pedestrians, with no increase in surface traffic upon the replacement Boulevard that would have to handle these new residents plus the vehicular traffic from the Expressway segments at both ends.

Looking North Along Farms Road Before and After The Removal of the northern portion of The Sheridan Expressway - an earlier proposal
Though the latter rendering has this portion of the Sheridan Expressway removed, though still fed by Expressway segments at both ends, and its space taken over by a new line of buildings, with over 1,000 new residential dwellings, it shows virtually no vehicular traffic.

And what about the pretense that its an either-or situation?  That re-development and improved local waterfront access is necessarily incompatible with retaining the Sheridan Expressway as assumed by this seriously misguided campaign to simply remove the Sheridan.

Have Sheridan Expressway removal advocates chosen to shut their eyes?  To fail to try imagining the best of both worlds, eliminating the Sheridan's undesirable local lateral separation, while retaining its desirable longitudinal grade separation of keeping the bulk of the vehicular traffic out of the surface street grid.  Instead just following an often overly simplistic and dogmatic trendy campaign of freeway removal?

Apparently so.

A Sheridan Expressway Tunnel would accomplish this best of both words, with express traffic underground, thus freeing up the surface more for local use.

Placing freeways underground is the best of both word's solution, but is often dismissed as too expensive or difficult.

But this actually a pretty egregious example of keeping one's eyes shut, of a freeway removal campaign  being deliberately obtuse.

Just look at the topography.

The Bruckner sits in a river valley, between the Bronx River to the east, and a hill to the west.

Note how Jennings, 172 and 173rd Streets descend to the existing West Farms Road.

Activists want to facilitate a locally improved environment with improved accessibility to the Bronx River waterfront, and new real estate developments on both sides of this Sheridan segment.

But they are retaining a major vehicular traffic corridor, and thus maintaining the surface separation of the Sheridan Expressway corridor, namely its daily flow of traffic particularly between the Cross Bronx Expressway and Hunts Point market.  Don't forget that this Sheridan segment would continue to be fed by Expressway segments at both ends, and that the area is only going to have far more activity with all of this new development, plus the new ramps to Hunts Point, to say nothing of such further south if the Re-Think NYC plan to add a new terminal to La Guardia Airport and its attendant new development at Port Morris comes to fruition.  Under such circumstances, ONLY a tunnel would achieve a 'Sheridan' surface street that would be truly more like a local surface street than a de-facto freeway.

So why the zero consideration of a 'tunnelization" of this Sheridan segment- especially given the topographical ease and feasibility of achieving this with such numerous cost advantages?

- Such as of NO new excavation.
- Such as of retaining the existing Sheridan Expressway roadbed that was recently replaced with a relatively high quality concrete construction- option #3 would require ripping this out and replacing it altogether.
- And the opportunity of facilitating this with the designs of the yet to be built flanking future real estate development.

Again, note how the streets from the west, Jennings, 172 and 173rd,  drop down to meet West Farms Road, where the planning envisions replacing the existing buildings with new taller/denser buildings, as well as along the eastern side nearer to the Bronx River.  And note that these new buildings flanking the Sheridan segment would be substantial, with significant foundation walls thus framing this Sheridan segment.

To make this Sheridan segment into a tunnel, while crafting a true boulevard on the surface, atop the existing road-bed, construct a new box tunnel enclosure-deck supporting a new surface boulevard atop, directly faced by the "1st" floors of the flanking new buildings, which could have their facing foundations serving as the outer walls of this new tunnel, retaining the existing flanking service roads as underground delivery access for these new buildings, with the streets from the hill to the west leveling out to meet this new boulevard, and a terrace to the east of this new development  facilitating the transition descent to the Bronx River water-front.

Constructing this deck would be an added cost, surely.

But employing the existing road-bed - remember that the option #3 promoted for increased space for real estate development requires ripping out and replacing the existing Sheridan Expressway road-bed - would be a cost savings.

And so would the idea of designing these buildings to serve essentially as the outer walls of this new 'tunnel' that would include the existing service roads potentially used for underground delivery access.  Doing this would furthermore allow the idea of reducing the initial construction costs by deferring the extra walls to coordinate off the now underground service roads from the now underground freeway.  As these buildings have not yet been constructed, designing them for this purpose, including having their '1st" floors to face this new surface boulevard would be infinitely more practical than a retrofit.

This new deck would start at some point to the north of 173rd Street, and extend south to the vicinity of Jennings Street, if not further to as far as Westchester Avenue, depending upon several planning decisions.  For instance it could extend as far north as the bridge which carries 174th Street, with its north-south 'Sheridan' Boulevard descending to connect to the existing West Farms underpass beneath this bridge, or perhaps continue upon its raised grade to a new at grade intersection with 174th Street, before descending to the north in order to connect to the existing underpass crossing of the Cross Bronx Expressway.  Or perhaps it could combine these options, extending to the 174 Street Bridge but with a descent to the existing West Farms Road grade, or even conceivably, extend a bit further north to cover over a portion of the eastbound Cross Bronx Expressway to the southbound Sheridan Expressway ramp.  Similarly, the extension to the south would involve some options, such as those regarding the southbound off-ramp.

By so retaining the existing Sheridan recycled as an underground highway in the least expensive manner possible with NO new excavation and freeway roadway replacement, with the existing highway enclosed in a new tunnel box constructed atop further facilitated by developer cooperation with the new buildings alongside --  in sharp contrast with Boston's Big Dig which actually relocated Boston's I-93 Central Artery in all new lowered tunnels --such an underground configuration would make the new development more pleasant and valuable, making such a lid more economically viable. 

That such an idea does not even appear in any of the great urban planning discussions,speaks volumes of the controlled, dogmatic and not very imaginative nature and political dynamics of such organizations as the Congress for New Urbanism.

Wednesday, April 6, 2016

3/31/16 Collapse Spotlights India's Hideous Roadway Urban 'Flyovers'

While areas worldwide are constructing unobtrusive underground motorways, India goes in the opposite direction with flyovers- elevated roadways of varying merit, including those placed above city streets, mere feet from people's bedrooms, as this in Calcutta with the Vivekananda Road 'flyover'

"Work on the Vivekananda Road flyover, which started in 2009, has gained pace after a long lull. The flyover, that will connect Girish Park and Nimtala Ghat Street to Howrah bridge, would allow commuters to bypass the congested Posta crossing.

Construction had almost stopped last year because of technical problems as well as objections from residents who apprehended accidents because the flyover runs close to their homes, said the authorities of Calcutta Metropolitan Authority (CMDA)."

The 1.4 mile (2.2 kilometer) long Vivekananda Road Flyover is one of a series of such elevated vehicular road 'fly-overs' constructed in India in recent years, itself being started in 2009.

The Vivekananda Road flyover is perhaps India's most extreme example of cramming an express roadway through a densely built up urban area, and numerous other Indian flyovers seen in various articles available via the internet, such as this, appear to be far less inappropriately situated, for instance not placing motor traffic directly by people's residences.

As can be seen from a google ariel, it has two main segments that are largely completed, with a not yet finished connecting segment, that collapsed on March 31, 2016, bringing the project much new attention.

The collapse occurred at the segment where the street has a right of way kink at the intersection with  Rabindra Sarani, where the designers were thus forced to use a single vertical support with cantilevers on each side, rather than double vertical supports as done on the rest of the viaduct.

  Kinked Right of Way

Single Vertical Support with Cantilevered Arms

 Customary Twin Vertical Supports

I think it seems quite clear what the fault is that caused the overpass to collapse in Kolkata. I can see that it may have been bad welding and even more profoundly bad engineering design (or bad construction if the drawings were not followed). The right arm of the support that collapsed was constructed with only a center column and two cantilevered arms. All the others had two legs and were thus not so structurally risky. It appears that the right arm broke off first, and then the left arm – absent its counterbalancing weight – simply buckled. The fault seems to be with the engineers, and not just with the builders, as it seems to me to be a particularly weak detail that would be prone to buckling because the members that held up the whole deck appear to be made up with tubes with sheets of steel no deeper in section than the steel beams that supported the deck along its length, with their ends resting on this weak cantilevered post and beam. The bending force at the top of the column must have been terrific, but it would appear from the buckling that the bottom cord did not even cross over the top of the column, as the column penetrates through the pair of cantilevered beams to terminate at the top cord. Wow! The reports said that they had just poured the concrete deck in this section when it failed, so it was simply inadequately designed to carry the weight of the road, never mind the traffic that will eventually be on it. The anomaly in the pier design seems to be because the road went around a bend in the street with a roundabout underneath – thus they did not want two legs on the support structure, but that has proved to be a mistake of gigantic proportions. The claims that this was an “Act of God” in my mind are incredibly misleading. Signed Randolph Langenbach ()

The above statement presumes that God acts only singularly and not sequentially, but is otherwise valid.

Though the collapse occurred at this naturally more vulnerable area, the project in general, and some other flyovers, have been criticized for poor quality construction.  The culmination of factors would thus work sequentially to bring about this March 31, 2016 collapse.

Matters of construction quality asides, how appropriate are elevated above street vehicular roadways in dense residential urban areas?   Even if well designed with relatively attractive undersides with added lighting, they introduce vehicular traffic mere feet from people's dwellings, with the attendant noise and safety risk from errant vehicles, and even with well designed enclosures, are visually significant, and thus should be accompanied with monetary payouts to the affected neighborhood.

Infinitely more appropriate for such contexts would be constructing additional vehicular roadway levels as tunnels, either drilled and or cut and cover.  As a relatively wide east-west traffic corridor, Vivekananda Road arguably could use a 2 lane plus one shoulder per direction cut and cover tunnel, somewhat akin to that beneath Washington, D.C.'s DuPont Circle.  If additional capacity is needed, the tunnel could have a lower level doubling the capacity, simplified with that being for longer distance traffic to thus reduce the costs and space requirements of having full access ramps for both levels at all of the planned intermediate access points.  The initial construction costs would be likelier higher than a viaduct, thusly why the consultants involved went with a viaduct.  But would not a viaduct in such a context be costlier in reduced property values?  And perhaps a cut and cover tunnel could be accomplished more cheaply if employing prefabricated segments, and made more practical by construction staged first with the upper level as pre-stressed tunnel box segments within slurry outer supports that extend deeper to thus allow the subsequent excavation of the lower level.

Additionally, for the broader picture, cities as Calcutta could improve highway networks via a greater use of the often wider right of ways exclusively used for railroads- in ways to not merely respect of improve the railroads, but to go further and heal the urban scar of vast rail-yards that divide local areas.

For instance, to the north of this viaduct, Calcutta has a generous somewhat paralleling railway corridor, that could conceivably re reconstructed to accommodate more than the existing rail activities- adding transportation options within a new set of tunnel boxes- of a new vehicular highway, improved rail service, while providing additional amenities atop a deck over with new buildings and linear parkland for the benefit of society at large. 

The new tunnel box vehicular highway could be achieved by one of several ways: a cut and cover tunnel directly beneath the railroad; one along the railroad; or perhaps as an ariel tunnel hidden within such new buildings, as done with an autobahn segment in Wilmersdorf, Berlin, Germany, or in the U.S.A. with Seattle,Washington's un-adopted Route 99 'Choppway' proposal; and such could also be adopted with a reconstructed or new rail transit line. 

Quality of construction and design should matter to those who state to be concerned about the impacts of transporation infrastructure.

Notably, publications as Streetsblog have not had much reporting upon such projects, as if the going on in third world countries matter little to the big money behind such publications that primarily focus upon shifting traffic burden to less affluent areas.