Cope Truss

Cope Truss
historic district contributing structure[1]
The 1906[2] Valley Forge Observation Tower was the 6th Cope Truss and was condemned and closed to the public in 1979. The tower's 4 columns spaced on a 24-foot square base supported a 20-foot square observation deck 72.5 ft above the ground.[3]
Country	United States
State	Pennsylvania
County	Adams
District	Gettysburg Historic
NPS unit	Gettysburg NMP
Landforms	Cemetery Hill Oak Ridge Warfield Ridge
Architect	Emmor Cope [4]

The Cope Truss uses tie bars as depicted in the top cell to prevent buckling by the eccentric load on the steel columns. The stairs, roof posts, and observation deck rails (not depicted) are part of the truss's load, as is the roof with flagpole.

Main article: List of truss types

The Cope Truss is a tall square frustum of four structural cells used for 2 lattice towers on the Gettysburg Battlefield: Culp's Hill Observation Tower and Confederate Avenue Observation Tower. The 60 and 75 ft (18 and 23 m) high observation towers have stairways with corner landings along the interior sides to form a square helix route to the "metal observatory".^[5] The Oak Ridge Observation Tower tower 23 ft (7.0 m) high and without a roof is truncated to the 1st cell.^[1]

History

Early Gettysburg sightseeing towers included an 1878 wooden observatory of 60 ft (18 m) on East Cemetery Hill,[1]^[6] an 1881 wooden tower on Big Round Top,^[7] and the Little Round Top observation deck on the c. 1890 castellated stone New York memorial. On April 30, 1895, contractors were solicited for steel War Department towers[2] [3] to support roofed observatories above the northeastern forest canopy (a 5th was contracted May 18, 1896).[4] The structures were manufactured and assembled by the Variety Iron Works of Cleveland, Ohio.[5] President Warren G. Harding used the Zeigler's Grove tower (1922),^[4] and Dwight D. Eisenhower with Omar Bradley used the Culp's Hill tower (1957).^[8] Beginning in the 1950s, the US Secret Service monitored tourists on the "Longstreet tower" along Confederate Av near the Eisenhower farm purchased in 1950.^[9]

The Zeigler's Grove Observation Tower removed in 1961 was replaced by the 1962 Cyclorama observation deck,[6] the Big Round Top Observation Tower was dismantled in 1968,^[5] and the Valley Forge tower was removed in 1988.^[10] After the 1974 opening of the private Gettysburg National Tower, a 1977 plan for removing the Gettysburg towers^[11] was not used, and the 1974 tower was instead razed in 2000. In 2002, structural maintenance included a "complete overhaul… to the historic steel and cast iron towers" for $384,675^[12] (the towers were painted in 1917 and 1926,^[13] and $45K was spent on the Culp's Hill tower in 1968).[7] The remaining 3 towers and the Big Round Top Observation Tower Foundation Ruin were "entered-documented" as historic district contributing structures in 2004.^[1]

External media
Images
	1913 image[where?]
	full-size Oak Ridge tower
	tower with flag on Confederate Av
	Zeigler's Grove tower & Brian House
Videos
	Big Round Top tower (minute 19:00), Zeigler's Grove tower (19:44, 20:15)

References

1. ^ ^{a b c} "Culp's Hill Observation Tower", "Oak Ridge Observation Tower", & "Confederate Avenue Observation Tower". (structure IDs 134,136,137; LCS IDs 080444,080428,080430) List of Classified Structures: GETT p. 3. National Park Service. http://www.hscl.cr.nps.gov/insidenps/report.asp?PARK=GETT&RECORDNO=54. Retrieved 2011-07-19. "16' sq at platform railing, 25' sq at base. Pier foundation. Steps 90 degree-change w/ landings winding to top. … steel platform, and a hip roof. Many ornamental details were eliminated…during rehabilitation in the early 1960s" 
2. ^ "Valley Forge Observation Tower..." (database record). Prints & Photographs Online Catalog (PPOC). www.loc.gov. http://www.loc.gov/pictures/item/PA1776/. Retrieved 2011-07-20. 
3. ^ Valley Forge Observation Tower (Report). Historic American Buildings Survey/Historic American Engineering Record. p. 2. http://lcweb2.loc.gov/cgi-bin/ampage?collId=pphhdatapage&fileName=pa/pa1700/pa1776/data/hhdatapage.db&recNum=3. Retrieved 2011-07-20. 
4. ^ ^{a b} "Traffic Rules on Battlefield" (Google News Archive). The Star and Sentinel. July 1, 1922. http://news.google.com/newspapers?id=Zk4mAAAAIBAJ&sjid=H_8FAAAAIBAJ&pg=916,4623905&dq=wheatfield-road+gettysburg&hl=en. Retrieved 2010-03-22. 
5. ^ ^{a b} "Big Round Top to be Dismantled" (Google News Archive). Gettysburg Times (Times and News Publishing Company). June 19, 1968. http://news.google.com/newspapers?id=vDUmAAAAIBAJ&sjid=cf4FAAAAIBAJ&pg=2480,948014&dq=round-top+tower&hl=en. Retrieved 2010-02-18. 
6. ^ http://news.google.com/newspapers?id=HXglAAAAIBAJ&sjid=2vIFAAAAIBAJ&pg=1298,1806035&dq=tower+round-top&hl=en
7. ^ "New Observatory" (Google News Archive). The Star and Sentinel: p. 3, col. 3. http://news.google.com/newspapers?id=pE8mAAAAIBAJ&sjid=U_8FAAAAIBAJ&pg=4431%2C886694. Retrieved 2011-03-13. 
8. ^ "National Affairs: New Battle of Gettysburg". Time. 1957-05-20. http://www.time.com/time/magazine/article/0,9171,809485,00.html. 
9. ^ Acrate, Bill (November 13, 1955). "Privacy a Problem for Ike on the Farm: Townspeople Help to Shield Chief Executive". Eugene Register-Guard. http://news.google.com/newspapers?id=wMcUAAAAIBAJ&sjid=d-IDAAAAIBAJ&pg=6608,2414170&dq=confederate+avenue+tower+gettysburg. Retrieved 2010-02-02. 
10. ^ http://www.nps.gov/vafo/historyculture/treese4b.htm
11. ^ "Proposed Master Plan Lists Long Range Ideas For National Park Here" (Google News Archive). Gettysburg Times. June 2, 1977. http://news.google.com/newspapers?id=p5syAAAAIBAJ&sjid=0OgFAAAAIBAJ&pg=1800,2284410&dq=tower+round-top&hl=en. Retrieved 2010-03-22. 
12. ^ http://news.google.com/newspapers?id=FS4yAAAAIBAJ&sjid=keUFAAAAIBAJ&pg=1930,1347715&dq=384675+oak-ridge-tower+gettysburg&hl=en
13. ^ Gettysburg National Military Park Commission. "Outline of consolidated statement of funds required for fiscal year 1932". The Gettysburg Commission Reports. Gettysburg, PA: War Department. http://www.gdg.org/Research/Authored%20Items/BCRReports/1932a.html.