Editing Brooklyn Bridge (section)

=== Towers ===
[[File:Standing_Tall_(2819665347).jpg|thumb|alt=View of the pointed arches of the suspension tower from below|Characteristic pointed arches of the bridge's [[Gothic Revival architecture|Gothic Revival]] suspension towers]]
The bridge's two suspension towers are {{convert|278|ft|m|abbr=}} tall with a footprint of {{Convert|140|by|59|ft|abbr=}} at the high water line.<ref name="Barnes p. 28" /><ref name="Facts on File 1914 p. 839" /><ref name="McCullough pp. 29-31" /> They are built of [[limestone]], [[granite]], and [[Rosendale cement]]. The limestone was quarried at the [[Ligonier Point Historic District|Clark Quarry]] in [[Essex County, New York]].<ref>{{cite web |url=https://s3.amazonaws.com/NARAprodstorage/lz/electronic-records/rg-079/NPS_NY/12001129.pdf |archive-url=https://web.archive.org/web/20210225060708/https://s3.amazonaws.com/NARAprodstorage/lz/electronic-records/rg-079/NPS_NY/12001129.pdf |archive-date=February 25, 2021 |url-status=live|title=National Register of Historic Places Registration Form: Ligonier Point Historic District |access-date=February 1, 2016 |first1=William E. |last1=Krattinger |first2=Darcey |last2=Hale |first3=Bruce |last3=Hale |first4=Morris |last4=Glenn |date=August 2012 |page=8}}</ref> The granite blocks were quarried and shaped on [[Vinalhaven, Maine|Vinalhaven Island, Maine]], under a contract with the Bodwell Granite Company, and delivered from Maine to New York by schooner.<ref>{{cite book |last1=McLane |first1=Charles B. |last2=McLane |first2=Carol Evarts |title=Islands of the Mid-Maine Coast |publisher=Tilbury House & Island Institute |volume=I |year=1997 |page=134 |isbn=978-0884481850}}</ref> The Manhattan tower contains {{Convert|46,945|yd3|m3|abbr=}} of masonry, while the Brooklyn tower has {{Convert|38,214|yd3|m3|abbr=}} of masonry.<ref name="NRHI Nomination Form p. 2" /><ref name="Barnes p. 28" /> There are 56 [[LED]] lamps mounted onto the towers.<ref name="Simko-Bednarski 2024 a204">{{cite web |last=Simko-Bednarski |first=Evan |date=January 11, 2024 |title=Brooklyn Bridge's New Bright Lights Shine on Storied NYC Landmark |url=https://www.nydailynews.com/2024/01/11/brooklyn-bridges-new-bright-lights-shine-on-storied-nyc-landmark/ |access-date=January 13, 2024 |website=New York Daily News |postscript=none |archive-date=January 13, 2024 |archive-url=https://web.archive.org/web/20240113030551/https://www.nydailynews.com/2024/01/11/brooklyn-bridges-new-bright-lights-shine-on-storied-nyc-landmark/ |url-status=live }}; {{cite web |last=Beer |first=Isabel Song |date=January 12, 2024 |title=DOT celebrates Brooklyn Bridge 'glow up,' iconic span will be lit for first time since 1983 |url=https://www.brooklynpaper.com/dot-brooklyn-bridge-glow-up/ |access-date=January 13, 2024 |website=Brooklyn Paper |archive-date=January 12, 2024 |archive-url=https://web.archive.org/web/20240112230357/https://www.brooklynpaper.com/dot-brooklyn-bridge-glow-up/ |url-status=live }}</ref>

Each tower contains a pair of [[Gothic Revival architecture|Gothic Revival]] pointed arches, through which the roadways run. The arch openings are {{Convert|117|ft|m|abbr=}} tall and {{Convert|33.75|ft|m|abbr=}} wide.<ref name="NRHI Nomination Form p. 5" /><ref name="McCullough p. 564" /> The tops of the towers are located {{Convert|159|ft|m|abbr=}} above the floor of each arch opening, while the floors of the openings are {{Convert|119.25|ft|m|abbr=}} above mean water level, giving the towers a total height of {{convert|278.25|ft}} above mean high water.<ref name="Barnes p. 28" /><ref name="McCullough p. 564">{{harvnb|ps=.|McCullough|1972|p=564}}</ref>

====Caissons====
The towers rest on underwater [[Caisson (engineering)|caissons]] made of [[southern yellow pine]] and filled with cement.<ref name="Barnes p. 28" /> Inside both caissons were spaces for construction workers. The Manhattan side's caisson is slightly larger, measuring {{Convert|172|by|102|ft|m|abbr=}} and located {{Convert|78.5|ft|m|abbr=}} below high water, while the Brooklyn side's caisson measures {{Convert|168|by|102|ft|m|abbr=}} and is located {{Convert|44.5|ft|m|abbr=}} below high water. The caissons were designed to hold at least the weight of the towers which would exert a pressure of {{Convert|5|ST/ft2||abbr=}} when fully built, but the caissons were over-engineered for safety. During an accident on the Brooklyn side, when air pressure was lost and the partially-built towers dropped full-force down, the caisson sustained an estimated pressure of {{Convert|23|ST/ft2||abbr=}} with only minor damage.<ref name="Barnes p. 28" /><ref>{{harvnb|ps=.|National Park Service|1966|pp=2, 5}}</ref> Most of the timber used in the bridge's construction, including in the caissons, came from mills at [[Gascoigne Bluff]] on [[St. Simons, Georgia|St. Simons Island, Georgia]].<ref>{{cite book | last1=Davis | first1=J. | last2=Galland | first2=B. | title=Island Time: An Illustrated History of St. Simons Island, Georgia | publisher=University of Georgia Press | year=2013 | isbn=978-0-8203-4245-0 | url=https://books.google.com/books?id=6QJ5AAAAQBAJ&pg=PA144 | access-date=February 16, 2020 | page=144}}</ref>

The Brooklyn side's caisson, which was built first, originally had a height of {{Convert|9.5|ft|m|abbr=}} and a ceiling composed of five layers of timber, each layer {{Convert|1|ft|m|abbr=}} tall. Ten more layers of timber were later added atop the ceiling, and the entire caisson was wrapped in tin and wood for further protection against flooding. The thickness of the caisson's sides was {{Convert|8|ft|m|abbr=}} at both the bottom and the top. The caisson had six chambers: two each for [[dredging]], supply shafts, and [[airlock]]s.<ref name="structure mag">{{cite web|url=https://www.structuremag.org/?p=10604|title=Brooklyn Bridge, Part 2|date=November 5, 2012|website=Structure magazine|access-date=June 18, 2019|archive-date=March 8, 2021|archive-url=https://web.archive.org/web/20210308125625/https://www.structuremag.org/?p=10604|url-status=live}}</ref><ref name="NRHI Nomination Form p. 2" />

The caisson on the Manhattan side was slightly different because it had to be installed at a greater depth. To protect against the increased air pressure at that depth, the Manhattan caisson had 22 layers of timber on its roof, seven more than its Brooklyn counterpart had. The Manhattan caisson also had fifty {{Convert|4|in|cm|abbr=|adj=mid|-diameter}} pipes for sand removal, a fireproof iron-boilerplate interior, and different airlocks and communication systems.<ref name="NRHI Nomination Form p. 5" /><ref name="structure mag" /><ref>{{harvnb|ps=.|McCullough|1972|pp=269–271}}</ref><ref name="nydh18710418">{{cite news|url=https://www.newspapers.com/clip/33000026/|title=Brooklyn's Bridge; The Mammoth Caisson for the New York Tower|date=April 18, 1871|work=[[New York Daily Herald]]|access-date=June 18, 2019|page=13|via=newspapers.com}}</ref>