Wednesday, April 17, 2013

Dissolving Border Vacuums, Part 6

SUPERBLOCK BORDER VACUUMS
Last time we looked at the border vacuums around congregational facilities, so this time let's examine those around “big footprint” developments, parking garages, and other facilities that come in superblock form.

Downtown Baltimore's superblocks.
WHAT'S A SUPERBLOCK?
In the simplest sense a superblock is either an abnormally-large block imposed in a top-down manner or a traditional block that has had its cross streets, alleys, and milieu of smaller buildings removed over the years. As seen in the diagram on the right, downtown Baltimore has several kinds of superblocks.

The first kind of superblock – the abnormally-large block – was often the product of urban renewal schemes in which smaller blocks were razed and merged into large “blank slates” to accommodate “big footprint” projects. The “big footprint” aspect was both literal and figurative: not only did these projects intend to serve as high-profile evidence of urban progress, but they also intended to turn stagnant urban economies around in one fell swoop. Unfortunately, while they were well-meaning, they were ineffective at best and sometimes only made things worse.

Charles Center (Charles Plaza+Center Plaza+Hopkins Plaza) is a relic of the “big footprint” approach. Other notorious examples include the Empire State Plaza in Albany, the Government Center in Boston, and the Renaissance Center in Detroit.

The second kind of superblock – the formerly fine-grained block that gradually gave way to a single megastructure – was not so much a product of urban renewal as it was a result of zoning, parking, taxation, and economic redevelopment inertia. For example, many blocks in downtown Baltimore once contained a milieu of mixed-use buildings punctuated by narrow streets and alleys. Over time many of these streets and alleys were removed, and blocks that once contained scores of buildings gave way to new blocks that contained just one or two megastructures. That is, blocks that had once been porous, fine-grained, and human-scaled were essentially reduced to large impervious boxes. Today nearly every block along the Inner Harbor has morphed into a superblock.

WHAT'S WRONG WITH SUPERBLOCKS AND WHY DO CITIES NEED SMALL BLOCKS?
In Chapter 9 of The Death and Life of Great American Cities, Jacobs argued that large blocks create numerous problems for cities:
  • As is self-evident, their geometry (their long unrelieved stretches and limited opportunities for turning the corner) undermines street life by restricting pedestrians' ability to casually traverse the street grid. Thus, unlike small blocks, they make it difficult for liveliness to spread from block to block (269).
  • The crimping of street life proceeds to undermine the economic vitality of residents and businesses in and around the superblocks, effectively isolating them: “People are kept too much apart to form pools of cross-use. [Large blocks] sort people into paths that meet too infrequently so that different uses near each other geographically are [still] blocked off from one another. Large blocks thwart the potential advantages cities offer to incubation, experimentation, and small enterprises (181-183).”
  • Even if superblocks have pedestrian walkways, they still often fail to support fine-grained interaction: “Even when they are laced with promenades and malls, and thus in theory possess 'streets' at reasonable intervals, these streets are meaningless because there is seldom any reason for people to use them (186).” Center Plaza, for example, has a walkway along its northern rim (where Lexington Street once ran), and a couple other walkways branch down to connect to Fayette Street, but these walkways are no substitutes for traditional streets containing a finer-grained mixture of uses and sights. While Charles Center thoughtfully integrated several existing buildings into its superblocks (unlike many “big footprint” developments in other cities), it still is no Charles Street (see below).
I'd rather be on Charles Street than in Charles Center!
Jacobs went on to argue that, instead of closing streets and alleys, cities should encourage their formation wherever possible: “Frequent streets and short blocks permit intricate cross-use. In successful districts streets are never made to disappear; wherever possible they multiply. Thus in Philadelphia, what were once alleys down the centers of blocks have become streets with buildings fronting on them. They often include commerce: the supply of feasible spots for commerce increases considerably, [as does] the distribution and convenience of their placement, [when streets are added] (180-186).”

Note the difference in porosity between traditional blocks and superblocks.
Take, for example, the stark difference between two adjacent blocks in downtown Baltimore (see right). The block bounded by Redwood, Calvert, Lombard, and Light Streets contains five alleys (some of them quite charming) and twenty buildings of various size containing hotels, restaurants, bars, shops, offices, and apartments. This rich mix of uses suggests that one justification for superblocks – that modern enterprises can't fit in smaller blocks and buildings – is debatable.

Compare this block to the block immediately to the south: it's occupied by a single megastructure that, save for the important Pratt Street frontage, is mostly ringed with parking garages, blank walls, and service infrastructure. The previous fine-grained block avoided this outcome by placing its “backstage” infrastructure along its alleys.

This is how Hopkins Plaza's Fallon Building greets Lombard Street!
The second block's perimeter shows us that, in addition to the problems Jacobs cited, many superblocks fragment the city by their sheer insularity (see left).

This phenomenon particularly irked William Whyte, and in Chapter 9 of The Social Life of Small Urban Spaces he argued strenuously against superblocks: “The ultimate development in the flight from the street is the urban fortress. [These] megastructures' enclosing walls are blank. [They are] going to date very badly, and they are a wretched model for the future of the city (85-89).”

In the film that accompanied the book, Whyte went even further in highlighting their absurdity: “Look at the wall the [Bonaventure complex] turns to [Los Angeles]. Have you ever seen a more brutal and unnecessary rejection of the street? Ironically, twenty miles away at Disneyland, people pay good money to enjoy a replica of a regular street with shops, windows, and doors! (00:25:25-00:27:40).” 

Although Charles Center wasn't deliberately standoffish like the “big footprint” fortresses in Atlanta, Detroit, LA, and elsewhere, it nevertheless gradually succumbed to insularity: not only were its street frontages dismal, but it pulled its plazas, shops, and walkways inward. For example, I would hardly bother venturing into Hopkins Plaza to linger on a windswept plaza ringed by cold office towers unless I was an office worker stepping outside for lunch.

Baltimore doesn't need more open space; it needs to use existing space better.
This gets to another problem: I think “open space” is overrated. Not only does Charles Center already contain vague setbacks and nebulous paved areas, but many of Baltimore's emergent superblocks – like the Transamerica Tower – are surrounded by open spaces of an even more ambiguous nature (see right). I'm quite sympathetic to the argument that downtown Baltimore frustratingly lacks the delightful squares popping up in other cities, but a cursory glance at an aerial view of downtown – particularly the rim of superblocks along Pratt Street – reveals that it's already saturated with rather useless scraps of open space.

Perhaps it'd be far more productive to maintain a limited number of squares enclosed by traditional streets and fine-grained blocks (like Armiger Square) than it would be to continue airlifting “object in the round” megastructures into ambiguous “green spaces” and “open spaces”? Central Florence thrives with just a few marvelous piazzas, yet downtown Baltimore has much more open space, most of which fails to attract a critical mass of people. In short, the downtown doesn't need more open space, rather it needs to concentrate activity in just a few intimate, well-defined plazas with “permeable membranes.”

Finally, superblocks fragment the urban fabric by reducing the number of streets between/through them, thereby concentrating traffic on a handful of arterials. This traffic would otherwise be distributed and diluted over a finer grain of streets.

DEAD IN THEORY, BUT STILL ALIVE IN PRACTICE?
At this point some people might insist that the superblock theory is long dead. But is it really? The aforementioned zoning, parking, taxation, and economic redevelopment inertia in Baltimore and elsewhere continue to induce megastructures. The dubious financing scheme that induced the partially blank-walled Hilton superblock next to Camden Yards is but one poignant example.

WHY ARE SUPERBLOCKS STILL INDUCED?
In Suburban Nation Duany, Plater-Zyberk, and Speck argued that zoning codes are partially responsible: “FAR (floor-area ratio), if combined with setback requirements, privileges large-lot development: two 5,000-square-foot lots are inferior to a single 10,000-square-foot lot in terms of their resulting FAR capacity, which discourages the involvement of small-scale developers downtown. This scenario leads cities to become dependent on a few large developers rather than on a diversity of local property owners (176-177).”

Parking mandates pose a substantial problem as well. It's difficult to provide off-street parking for new (or renovated/converted) smaller buildings: where will it fit? It thus makes sense to raze smaller buildings and merge their lots into blocks large enough to accommodate off-street parking: “Most cities require new and renovated buildings to provide their own parking. This prevents the renovation of old buildings since there is inadequate room on their sites for parking, it encourages the construction of anti-pedestrian buildings [that] sit behind or hover above parking garages, and it eliminates street life since everyone parks immediately adjacent to their destination and has no reason to walk, [thus preventing] a downtown from achieving critical mass. Cities should eliminate this ordinance immediately (Ibid., 163).”

Parking mandates may be one reason why many of the upper floors in downtown Baltimore's older, smaller buildings sit vacant. (Inflexible building codes are another, as seen with the decay and challenging subsequent renovation of the Brexton Hotel.) These empty floors are just begging to be converted into cheap lofts for the young people flooding into Baltimore, but if their conversion triggers off-street parking mandates, then cost-effective adaptive reuse can be impractical. I therefore think Baltimore's zoning code overhaul should rescind all downtown parking minimums (thus obviating the need for case-by-case variances). This might accelerate the adaptive reuse/conversion of existing small buildings and encourage the construction of smaller infill buildings.

The parking issue is intertwined with yet another issue: the quality of public transit. In cases where they're not induced by parking mandates, the parking garages that accompany superblocks are probably provided under the assumption that the alternative (public transit) simply isn't good enough. That is, developers may feel their units won't sell if they lack parking.

Unfortunately there's no easy solution to this predicament. Parking garages can incorporate retail liners (Baltimore already has a few examples), but the downtown is already saturated with parking garages, so the only effective solution is a long-term one: the public transit system must be incrementally improved. A reliance on quick-fix parking garage liners might result in an absurd scenario in which there'd be too few people nearby to support the proliferation of retail liners. Downtown retail demand is already rather weak – it makes little sense to add retail-lined parking garages when so many existing shopfronts already sit empty.

These vacant buildings have been waiting for the Superblock for years...
Unwieldy taxation can also induce superblocks by restricting the ability of smaller property owners to participate in finer-grained redevelopment, thus forcing cities to rely on a handful of the aforementioned large developers. Since these developers operate on large “economies of scale,” they're compelled to combine small buildings/lots into large parcels dependent on complex-but-brittle financing schemes. The end result is that development proceeds at a glacial pace: “Only one project may get built every five years, with that project absorbing all the demand of the next five years. Half the city [thus] sits empty while huge projects land in isolated locations like spaceships (Ibid., 173-174).” The perpetually-stalled Superblock project (note the nickname!) reflects this predicament.

The land slated for future superblocks is often held in speculative cold storage for years or even decades. This land usually comes in the form of mothballed vacant buildings, vacant lots, and/or “temporary” parking lots, and these form border vacuums long before a superblock even arrives! This is precisely the case with the Superblock: some of the site's existing buildings are slated for “facadism” into a megastructure with an uncertain future, so they languish in dereliction and vacancy (see above).

So zoning, parking, taxation, and economic development reforms could encourage finer-grained redevelopment, but is there any way to fix existing superblocks?

REINTRODUCING CROSS STREETS
Perhaps one of the easiest strategies for dissolving “open space” superblocks is to simply reintroduce their missing cross streets and alleys. For example, the BCPSS superblock currently clips Guilford Avenue for one block; extending Guilford Avenue across the parking lot seems like a no-brainer.

RECONFIGURING THE GROUND FLOOR
Superblock complexes require periodic renovation like any other building, so when that time comes it may be possible to thoughtfully reconfigure their ground floors:

It's possible to retrofit storefronts into a superblock's blank walls and parking garages, and to the city's credit, there already is a proposal to add retail frontages to several superblocks along Pratt Street. The strategy has its limits, of course: there is the risk of saturating the downtown with too much retail space (as discussed earlier, downtown retail demand is already weak). It may be preferable to retrofit just one superblock and, if it succeeds, to incrementally retrofit additional superblocks on a block-by-block basis (assuming the city continues infilling downtown parking lots and converting vacant office buildings into apartments).

The St. James Hotel offered a line of shops to Centre Street.
Some superblocks, like hotels, can simply move their internally-oriented semipublic programming – restaurants, gift shops, etc. – into new retail liners. Not only does this enliven the street, but it boosts the hotel's profile as well. This strategy was once quite common in Baltimore and elsewhere (see right), but, save for a few exceptions, it's rather rare now.

It's also possible to run arcades through superblocks. This allows pedestrians to cut through them rather than having to walk around their perimeter. As is perhaps self-evident, these arcades need to be lined with shops and other attractions, otherwise they'd be no better than the desolate walkways/skywalks in “big footprint” projects. Brown's Arcade is a useful precedent in this regard, as is Lexington Market.

What about superblocks that are elevated above street level on podiums or plinths? The Monumental Life Building, for example, offers a blank wall to Biddle Street. It's possible to punch storefronts through these blank walls (and sacrifice some of the parking that may be lurking behind them). To its credit, One Charles Center does exactly this along Fayette Street.

The Charles Towers greet Charles Street with a retail complex.
INFILLING SETBACKS
If a superblock is of the “tower in the plaza” variety, it's possible to infill the plaza with mixed-use buildings. Charles Plaza, for example, once had all the charm of East Berlin, but it was partially infilled with a reconfigured retail complex. The strategy addressed an important issue: urban retail can struggle if it's set back too far from the street (as was the case with the older shopping complex on the plaza), so it should be made as prominent as possible (perhaps an early proposal for building the new complex right out to the sidewalk would have been even better). A similar strategy might work for Baltimore's many other superblock outparcels: the Transamerica Tower's plaza, for example, could be infilled with walkups or mixed-use buildings.

If permanent infill isn't feasible yet, it's possible to activate the ambiguous setbacks with tactical/popup urbanism. That is, the “open spaces” can be programmed with performances, festivals, markets, interactive installations, and other events. As in the discussion on elevated transportation corridors, however, this strategy assumes there's a large-enough pool of people nearby to support the programming. Furthermore, the more “open spaces” there are, the harder it is to inject enough programming to enliven them all.

BREAKING UP “BIG FOOTPRINT” PROJECTS
I think the best way to fix “big footprint” superblocks is to integrate them back into the street-and-block grid. For example, while the recent renovation of Center Plaza was certainly an improvement, I still think the fundamental problem with Charles Center – that it's essentially introverted – remains unaddressed. So how exactly do you dissolve a “big footprint” superblock back into the urban fabric?

In the case of Center Plaza, it may be possible to reopen Lexington Street as a narrow shared street and run two additional such streets down to Fayette Street (see right). For these streets (and the plaza in the center) to work properly, of course, the aforementioned “permeable membrane” would need to be introduced wherever it's missing. The Park Charles Apartments and One Charles Center already offer (partial) retail liners to the plaza (though they could be more porous), but liners could be inserted into the BGE complex's arcade as well.

It might even be possible to add modest walkup or loft-style units above and around these liners to create a narrow-street-style human presence – something that's difficult to do solely with highrises. (Vancouver, for example, has long worked walkups into and around highrises.)

A similar process might work for Hopkins Plaza (see right): Hanover Street could be reintroduced as a shared street and extended all the way down to Lombard Street; likewise Redwood Street could be extended all the way to Hopkins Place. These new shared streets would define the central plaza, and the entire ensemble could be enclosed with mixed-use buildings.

In short, the essential strategy required is this: don't define buildings with space; define space with buildings! If you define buildings with space, you just get a nebulous “open space” residue that isn't really good for anything. The best public spaces feel like intimate outdoor rooms.

INCORPORATING PERIMETER BLOCKS AND STEPPED HIGHRISES
There probably always will be some enterprises that require larger floorplates and buildings. But it's still possible to mitigate their border vacuums by employing more thoughtful building masses in conjunction with the previously-discussed solutions.

As discussed earlier, many superblocks place their primary programming in the center of the block and surround it with ancillary support functions, like parking, service, and delivery infrastructure. This, of course, results in superblocks presenting nothing but blank walls, service doors, loading docks/drives, exhaust grilles/vents, and parking garages to the street. Lombard Street, for example, has essentially devolved into a service drive for the Inner Harbor's superblocks.

Perimeter blocks in Hamburg, Germany.
The perimeter block solves this problem by simply inverting the programming sequence: it places the unpleasant (but necessary) service infrastructure in the center of the block, and the primary programming (the hotel rooms, offices, apartments, shops, etc.) on the edge of the block along the street. Mid-block portals provide access to the “backstage” infrastructure in the center. The Station North Townhomes are a good  example of the perimeter block strategy; Jefferson Square at Washington Hill is another (though I'd urge the developer to extend Fairmount Avenue across the site).

Finally, is there a way for cities to comfortably accommodate highrise superblocks? Many highrises of the “tower in the plaza” variety, like the Transamerica Tower or the towers in the Charles Center superblocks, were set back from the street and from each other so that their clustering wouldn't create a claustrophobic canyon effect. (For example, imagine the unpleasant outcome of having a downtown composed of tightly-packed wall-to-wall highrises in the manner of the B&O Building and the Lord Baltimore Hotel.) Unfortunately, while the setback strategy is understandable, the setbacks often devolve into ambiguous wastelands, as discussed earlier.

It may be preferable to adopt stepped or “wedding cake” highrises akin to those built in New York under that city's 1916 zoning resolution (Baltimore has its own 10 Light Street precedent). This way, rather than relying on banal street-level setbacks that interrupt the “street wall,” stepped highrises can be built right out to the sidewalk. The Empire State Building, for example, greets Fifth Avenue with a comfortably-scaled, retail-lined facade.

Next time we'll look at solutions for the border vacuums around radiant/garden city complexes (like housing projects, strip malls, and office/government parks), so stay tuned!

- Marc Szarkowski

2 comments:

  1. One of the benefits of the discontinuous street pattern is that it discourages or even precludes through motor vehicle traffic, while remaining pervious to bicycle travel. This is the essence of the "bike-boulevard", a semi-reserved facility which can help get more cyclists on the road. Guilford Avenue was chosen as the city's first bike-boulevard precisely because the BCPSS "roadblock" decreased to auto traffic and considerably calmed the route. The same can be said for the Lexington Street corridor on the west side of downtown. We need a careful balance between providing enough traffic to ensure vibrancy, while not so much that we just create another bike-hostile urban speedway.

    Greg Hinchliffe

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  2. That's a good point, however I'm of the opinion that it may be a better idea to *discipline* vehicular traffic than remove it altogether. For example, some bicyclists have said they prefer riding in traffic (i.e. on Charles Street) because it feels safer than Guilford. Likewise the pedestrianization of Lexington Street only undermined the businesses along that street, resulting in its recent reopening to vehicular traffic.

    I think you can maintain connected street grids without resorting to roadblocks and closures - tighter geometries, narrowness, different pavement materials, and other such tactics can slow or discourage some vehicular traffic without banishing it altogether. For example, for all the Hilton superblock's flaws, I kinda like the treatment on the one-block stretch of Eutaw Street that runs through it, though it still could be better. The dimensional and pavement treatment is almost of a rudimentary "shared street" nature: it suggests pedestrians and bicyclists can take up as much of the street as they need while at the same time cuing drivers to proceed slowly by dimensionally/materially suggesting the street is not meant for heavy through-traffic.

    I agree, though, that it's possible to provide a balance. The caveat is this: if there are too many specialized street closures or roadblock-type diverters, then traffic is pretty much forced onto a limited number of streets, thereby insuring their transformation into hostile speedways. The finer grain of streets, the greater potential for diluting traffic so that no one street need be overloaded with too many cars.

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