{"nrhp_refnum":"88000847","name":"Thirty-third Street Bridge in Philadelphia","other_names":[],"category":"structure","location":{"address":"Thirty-third St. over Master St.","address_restricted":false,"city":"Philadelphia","county":"Philadelphia","state":"PA","lat":39.97880896800007,"lon":-75.18957878399993,"geom_source":"nps_gis"},"listed_date":"1988-06-22","is_nhl":false,"nhl_designated_date":null,"areas_of_significance":["Engineering"],"significance_levels":["state"],"summary":{"what_it_is":"A single-span stone arch bridge carrying vehicular traffic over 33rd Street in Philadelphia, Pennsylvania. The form gives its date as 1901 and lists the designer and builder as unknown.","why_significant":"The nomination argues the bridge is an unusual and excellent example of a skew arch built with brick ribs, in the manner described in contemporary texts. The individual obliquely-angled brick ribs are visible from inside the barrel. It is the only bridge in the nominated group with skewed brick ribs. The area of significance is engineering.","narrative":"Built about 1901 over 33rd Street in Philadelphia, this single-span stone arch bridge carries vehicular traffic across the street. Its main span measures 41 feet, and the overall length is 85 feet. Its significance lies in engineering. The arch is a skew arch built with brick ribs, constructed in the manner described in contemporary engineering texts. When viewed from inside the barrel, the individual obliquely angled brick ribs can be seen. The spandrel walls and voussoirs are of ashlar masonry, and the wing walls are semi-coursed masonry. Among the bridges in the nominated group, it is the only one with skewed brick ribs. The bridge is regarded as unaltered from its original form. The nominated boundary covers only the bridge superstructure and substructure, within the outside corners of the wing walls.","period_of_significance":null,"architect_builder":null,"architectural_style":null,"criteria":[],"status_note":"Unaltered, in vehicular use.","vacant_flag":false,"machine_generated":true,"model":"claude-haiku-5-5","prompt_version":"v1.1-2026-10-29","generated_at":"2026-10-29 17:11:35.972505-05","source_pdf":"https://s3.amazonaws.com/NARAprodstorage/lz/electronic-records/rg-079/NPS_PA/88000847.pdf"},"photo":{"url_800":"https://nationalhistoricalregister.com/media/88000847/d0db027b45-800.webp","url_1600":"https://nationalhistoricalregister.com/media/88000847/d0db027b45-1600.webp","licence":"Public domain","author":"Smallbones","credit_html":"<a href=\"https://commons.wikimedia.org/wiki/File:33rd_st_bridge_Philly_a.JPG\" rel=\"noopener\">Smallbones</a>, Public domain, via Wikimedia Commons","source_page":"https://commons.wikimedia.org/wiki/File:33rd_st_bridge_Philly_a.JPG"},"district":{"nrhp_refnum":"72001151","name":"Fairmount Park","url":"https://nationalhistoricalregister.com/districts/pennsylvania/fairmount-park-72001151/"},"sources":{"nps_snapshot_date":"2026-05-22","nara_catalog":"https://catalog.archives.gov/id/71993801","wikipedia":"https://en.wikipedia.org/wiki/Thirty-third_Street_Bridge_in_Philadelphia","wikidata":"https://www.wikidata.org/wiki/Q7785213"},"indexable":true,"url":"https://nationalhistoricalregister.com/pennsylvania/philadelphia/thirty-third-street-bridge-in-philadelphia-88000847/"}