A Google search for "sidewalk vault" on the internet 4/23/06 turned up a relevant sites. Here they are, from the first 50:
"The outer edge of all openings constructed in sidewalks for fuel, elevators, stairs, or other purposes shall be located not less than 2 feet from the curb line..."
* Descriptions and a photo of existing Sidewalk Basements from a contractor company's website: Ask the Engineer: Replacing a Sidewalk Vault.
"A common sidewalk vault structure consists of an approximately four-inch thick slab of sidewalk concrete on top of a waterproofing membrane, supported by a structural slab four to six inches thick. The entire sidewalk structure itself is supported by either a metal deck (common in recently built or replaced vaults) or (in most older buildings) by a series of steel cross beams and columns spanning between the structural members along the building line and a brick or concrete foundation wall that separates the vault space from the ground underneath the street."
The National Park Sevice has a guidebook on caring for Sidewalk Basement glass lights: PRESERVATION Tech Notes: Repair and Rehabilitation of Historic Sidewalk Vault Lights
"Beginning in the 1850s, sidewalk vault lights became a common feature amidst the burgeoning manufacturing districts of America's urban streetscapes. These cast-iron panels, fitted with clear glass lenses, were set into the sidewalk in front of building storefronts. They permitted daylight to reach otherwise dark basements (or "vaults") that extended out beneath the sidewalks, creating more useable or rentable space for building owners."
A glimpse of a sidewalk basement, by reverse illumination coming through a cast iron step:
NewYorkDailyPhoto : Sidewalk Vault Lights
A bad example of a sidewalk vault - a death caused by door failure: Hazard of Potential Sidewalk Grate System Failure
"Many sidewalks and roadways near large urban buildings incorporate surface grate systems to cover vaults and pits. In heavy snowstorms, snow accumulates on the grates. During a snowstorm in 2003, a skid-steer loader being used to clear sidewalk snow fell into a vault when the grate system failed under the weight of the loader, fatally injuring the operator. ... The load caused the bolts to fail, pulling the angle iron away from the concrete and permitting the grates and the skid-steer loader to drop approximately 20 feet."
** Hypertexted pages from a catalogs showcasing products of the American Luxfer Prism Company include prism glass designed to light Sidewalk Basements: STEEL-
CONCRETE SIDEWALKS - PRISM LIGHTS (1906) and AMERICAN LUXFER PRISM COMPANY - Luxfer Prisms for Lighting Buildings with Daylight (1915)
"We are the manufacturers of the original "Luxfer" Prisms, making them for every conceivable position where it may be necessary to flood buildings with daylight. Upwards of 12,000 buildings have been successfully equipped with LUXFER PRISM WINDOWS AND TRANSOMS, LUXFER SKYLIGHT PRISMS, LUXFER PAVEMENT PRISMS, LUXFER SHEET PRISMS, LUXFER FIREPROOF WINDOWS. ...
"These slabs of glass and concrete are supported upon retaining wall and beam at building, and have stiffeners of steel I-beams or concrete trusses placed at proper intervals."
*** A long hypertext page listing sidewalk light in a Canadian city: Historic Sidewalk Prisms in Downtown Victoria, British Columbia.
(The sidewalk basement illustration is from Glassian.org's webpage on the advertisement of a vault glass manufacturer; see below.)
"Historic sidewalk prisms ( 3" purple glass squares) dating from the early 1900s are in place at five locations in downtown Victoria, British Columbia. Though thousands of pedestrians walk over the glass grids each day, few notice or fully appreciate these wonderful heritage features. There has been little information, no map, sign, or list of locations and no complete inventory of sidewalk prisms available. This report aims to fill that gap."
"... Victoria and Vancouver refer to these heritage features as 'sidewalk prisms.' In the United States, the term usually used is 'vault lights.' In the U.K. and Australia, they are called 'pavement lights.'"
A glimpse at Sidewalk Basements through a misconception: "Chinese Tunnels"
"Many communities where large numbers of Chinese people once lived are today rumored to have so-called "Chinese tunnels" under downtown buildings and streets. This myth continues to be perpetuated despite overwhelming evidence to the contrary."
"In Lewiston, Idaho, for example, Erb Hardware Company President Jeanine Bennett graciously led Wegars on a tour of the store's basement areas, in response to a local newspaper's suggestion that it contained entrances to such 'tunnels.' Instead, the arched openings actually lead to passageways under the sidewalk (today either in use as storage areas, or blocked up) that were once used for delivery access, or to admit light. The architectural term for these passageways is 'sidewalk vaults.'"
A NY contractor advertizing its experience with Sidewalk Basements:
CROWN CONTRACTING NY LTD. : Sidewalk Vault Repair
"Vault work encompasses all aspects of vaults: Repair & replacement of structural steel supports, reinforced structural slabs over metal deck, waterproofing over vault, and topped with sidewalk slabs and curbs. Vault downsizing as well as installation of new vaults. We have extensive experience with vaults and all work is permitted by the NYC DOT & DOB."
"Shown here: Extensive vault work - Complete demolition of sidewalk, structural slab and steel I-Beams of vault roof."
A Google search for "sidewalk underground" on the internet 4/23/06 turned up some intersting and relevant sites. Here they are, from the first 50:
Three photos of a tour of Seattle underground: Adam Lyon's photo gallery: Seattle
"I have wandered long "streets" of Underground Seattle below 1st avenue, next to the Farmer's Market, under the Pioneer Square, & under Chinatown. I began exploring this area when I was a teenager circa 1964/66 -- I probably made my last visit circa 1982. Much of what I strode no longer exists, but some bits of it are still there."
"The places described in my novelette "A Child of Earth & Hell" first anthologized in The Berkley Showcase and included in my collection A Silver Thread of Madness -- they were places I actually visited."
** Cover story in the Sacramento News & Review about that city's underground sidewalks: "The past below - The forgotten city beneath modern Sacramento, known as 'the underground,' is shrouded in mystery and rife with urban myths. But this is true: It has historical significance and should be preserved."
"The mystery of the haunted basement fits somewhere in the vast constellation of stories--some documented, some pure fantasy and the majority somewhere in between--about Sacramento's 'underground city.' There is indeed a presence people feel here, as there is throughout much of the moldering and largely forgotten city beneath the streets. Whether it's really poltergeists or just the power of old places, there is something about the underground that stokes the imagination."
"The stories often refer to the 'tunnels.' More romantically, they are called the 'Chinese tunnels' or the 'catacombs.' The folks who spend the most time investigating this subterranean world, the city Department of Public Works, call one aspect simply 'hollow sidewalks.' More often than not, these areas are referred to in a larger sense as the 'underground.' They are the setting for all sorts of urban myths--about runaway kids, Chinese gangs smuggling contraband, and, of course, ghosts."
** A Seattle article on architectural subterranea for kids: What Lies Beneath - The true story about areaways in Seattle"
"Areaways are open underground spaces like tunnels but they aren't exactly tunnels: though some are linked together underground by short tunnels, other areaway spaces are isolated and not connected to any of the others (at least, not anymore)."
* The Seattle tour itself: BILL SPEIDEL'S UNDERGROUND TOUR is a leisurely, guided walking tour beneath Seattle's sidewalks and streets."
"While you roam the subterranean passages that once were the main roadways and first-floor storefronts of old downtown Seattle, Tour Guides regale you with humorous stories our pioneers didn't want you to hear. It's history with a twist!"
"Be prepared for the underground landscape to be moderately rugged: you'll encounter six flights of stairs, uneven terrain and spotty lighting. Dress for the weather - and leave your spike heel shoes at home!"
*** Glassian.org is a huge website on glass by Ian Macky. A webchapter is on prism glass, which includes "Vault Lights." The presence of vault lights indicate the presence of sidewalk basements.
*** An advertisement of a vault glass manufacturer: Brown Brothers Sidewalk & Vault Lights Broadsheet. The center of this is the illustration of a sidewalk basement tht is also featured in Historic Sidewalk Prisms in Downtown Victoria, British Columbia.
A browsing through the first 50 Illustrations of Vault Glass in Glassian.org. (Use the arrows to the left of each webpage to progress through them.)
1857 diagram of a "Vault Cover": Cornell - "Metallic Roofing for Subterranean Vaults" - Drawing. Simple cross sections of a sidewalk basement roofed with cast-iron. In <glassian.org>. "The accompanying drawings representing a subterranean apartment which extends under the side-walk and also under a portion of the street in front of the basement of a Broadway store in the city of New York."
1857 diagram of a "Vault Cover": "Illuminating Roofs and Roof Pavements". Another simple cross sections of a sidewalk basement roofed with cast-iron. In <glassian.org>.
"[T]he purpose the invention being to change the use of the space underneath sidewalks from coal-vaults to finished apartments capable of becoming a portion of the basement."
"I do not claim to be the first to enlarge a basement by taking into it the area-space, nor the first to incorporate the area-space into the basement by a glass covering; but I do set forth as my invention that my glass covering does not barricade the doorways of the building. ... The only actual basement extension which I found when I began my improvements was where the area-way alone was taken into the basement, not the vault beyond it, and this area was covered by a skylight, and this skylight was above the level of the street, and then the whole thing was cut off from the sidewalk by an iron railing. This was the state of the art as I found it."
"All other underground rooms existing at that period, those at the New York Sun buildings included, were simply vaults, and lighted from light-holes. All were apartments distinct from the basements, and none of them were able to add light to the basement, for they had not sufficient light for themselves."
"The first thoroughly-lighted vault ever constructed was made so by a sidewalk of my lights, laid by me for the New York Herald building in the year 1850. This enabled me, two years later, to get the opportunity of laying down an actual basement extension, taking in all the space under the sidewalk, and going two stories under ground; but that year, the following, and the next were required in order to perfect the work so as to secure the public confidence, which was accomplished only when, after repeated failures, I at length succeeded in making water-tight joints that would stand both summer and winter and concussions of every kind and constantly repeated."
"Drawing B is a sectional elevation of a building, where A is the area-space underneath the area-light A L. V S is the vault-space under the sidewalk S W, here formed of granite slabs. B is the basement. P S is the first or principal story. d s is the illuminating door-sill. r is the illuminating-rider under the door-sill; F, the "rising lip" of the area-light. G is the nosing of the area-light where it sets over the iron riser at the sidewalk."
"[T]he extension of basements under the street by means of an illuminating-roof pavement is my invention, for a roof-pavement in such a combination of glass with iron as to be fit for being walked upon. What I mean to say is that until I did it no area-way was ever covered, and no basement was ever extended under the street by glass and iron combined to form substantially a portion of the sidewalk itself."
*** Not quite on the internet (yet?), but an excellent illustration of a concrete sidewalk basement is this illustration from Areas, Vaults, and Retaining Walls, William S. Lowndes, Ph. B. (International Textbook Press 1919) which is listed in Glassian.org's Bibliography. The image is second-hand from Glassian.org.
...Continued in webpage 2.
