{"nrhp_refnum":"73001428","name":"Detroit Avenue Bridge","other_names":["Rocky River Bridge"],"category":"structure","location":{"address":"Detroit Ave. at Rocky River","address_restricted":false,"city":"Rocky River--Lakewood","county":"Cuyahoga County","state":"OH","lat":41.48261825600008,"lon":-81.83111810699995,"geom_source":"nps_gis"},"listed_date":"1973-02-23","is_nhl":false,"nhl_designated_date":null,"areas_of_significance":["Engineering","Transportation"],"significance_levels":["state"],"summary":{"what_it_is":"A 708-foot unreinforced concrete arch bridge carrying Detroit Avenue over the Rocky River gorge between Rocky River and Lakewood, Cuyahoga County, Ohio, built 1908-1910 and designed by county engineer A. M. Felgate.","why_significant":"For a brief period after completion, it had the longest main span of any unreinforced concrete masonry arch in the world. It is the fourth bridge at this crossing and reflects the area's transportation history and the need for a high-level span after the turn of the century.","narrative":"Spanning the deep shale gorge of the Rocky River between Rocky River and Lakewood, this concrete arch bridge carries Detroit Avenue about 95 feet above the water. Built between 1908 and 1910 to a design by county engineer A. M. Felgate, and constructed by the Schillinger Brothers Company for $224,850, it runs roughly 708 feet and centers on a twin ribbed, open-spandrel arch with a 280-foot clear span, plus five 44-foot approach arches. It was designed to carry heavy interurban rail cars, two lanes of traffic and sidewalks. It was the fourth crossing at the site, following a low-level bridge of 1821, a toll bridge of 1850 and an iron bridge of 1889. For a short time its main span was the longest of any unreinforced concrete masonry arch in the world. The structure has been used continuously, though its deck has deteriorated and needs replacement while the arches and piers remain sound.","period_of_significance":"20th Century (specific date 1910)","architect_builder":"Designed by county engineer A. M. Felgate; built by the Schillinger Brothers Company","architectural_style":null,"criteria":[],"status_note":"Listed as in good condition and in continuous use since construction; the arch ribs and piers are sound but the deck needs full replacement, and its future was to be considered by the county engineer.","vacant_flag":false,"machine_generated":true,"model":"claude-sonnet-5-5","prompt_version":"v1.0-2026-10-29","generated_at":"2026-10-29 02:53:09.713631-05","source_pdf":"https://s3.amazonaws.com/NARAprodstorage/lz/electronic-records/rg-079/NPS_OH/73001428.pdf"},"photo":{"url_800":"https://nationalhistoricalregister.com/media/73001428/b0b43eb9cc-800.webp","url_1600":"https://nationalhistoricalregister.com/media/73001428/b0b43eb9cc-1600.webp","licence":"Public domain","author":null,"credit_html":"<a href=\"https://commons.wikimedia.org/wiki/File:Photocopy_of_a_photograph_(original_negative_in_the_archives_of_the_Cleveland_Plain_Dealer)-1930_VIEW_OF_ROCKY_RIVER_BRIDGE_LOOKING_WEST,_WITH_WESTLAKE_HOTEL_IN_BACKGROUND_-_HAER_OHIO,18-RORI,1-14.tif\" rel=\"noopener\">Unknown author</a>, Public domain, via Wikimedia Commons","source_page":"https://commons.wikimedia.org/wiki/File:Photocopy_of_a_photograph_(original_negative_in_the_archives_of_the_Cleveland_Plain_Dealer)-1930_VIEW_OF_ROCKY_RIVER_BRIDGE_LOOKING_WEST,_WITH_WESTLAKE_HOTEL_IN_BACKGROUND_-_HAER_OHIO,18-RORI,1-14.tif"},"district":null,"sources":{"nps_snapshot_date":"2026-05-22","nara_catalog":"https://catalog.archives.gov/id/71987875","wikipedia":null,"wikidata":"https://www.wikidata.org/wiki/Q21036996"},"indexable":true,"url":"https://nationalhistoricalregister.com/ohio/cuyahoga-county/detroit-avenue-bridge-73001428/"}