. Concrete bridges and culverts, for both railroads and highways . n can at any time oc-cur in any part of the arcli. The sidewalks ])rojectout over the face walls about five feet, and are sup-ported on brackets. The entire structure will bebuilt of concrete. It will be quite similar to and -17feet longer than the Walnut Lane Bridge at Phila-delphia. The only longer masonry arch span in ex-istence is the one at Plauen. in Germany, with aspan of 296 feet, built of hard slate. Other pro-jected long-span bridges are that over the NeckarRiver at IManheim, with a span of 365 feet, and theHudson ]\r
. Concrete bridges and culverts, for both railroads and highways . n can at any time oc-cur in any part of the arcli. The sidewalks ])rojectout over the face walls about five feet, and are sup-ported on brackets. The entire structure will bebuilt of concrete. It will be quite similar to and -17feet longer than the Walnut Lane Bridge at Phila-delphia. The only longer masonry arch span in ex-istence is the one at Plauen. in Germany, with aspan of 296 feet, built of hard slate. Other pro-jected long-span bridges are that over the NeckarRiver at IManheim, with a span of 365 feet, and theHudson ]\remorial Bridge in New York City, with aspan of 703 feet. The Eocky TJiver Bridge was de-signed under the direction of A. B. Lea, CountyEngineer, by A. M. Felgate, Bridge Engineer. It isunder construction by Schillinger Brothers, con-tractors of Chicago. Wilbur J. AYatson, Engineer. Walnut Lane Bridge, Philadelphia. Walnut Lane crosses the AYissahickon valley ona new concrete bridge at a height of 147 feet abovethe river bed. At the timie of completion it was the. at o 86 COXCRETE BRIDGES AXD CULVERTS. longest concrete masonry bridge, having a clearspan of 233 feet. It consists of two separate archrings, 18 feet wide at the crown, increasing to 21feet 6 inches at the springs. At the crown the tworings are separated by a space of 16 feet. Thedouble rib construction is similar to that used inthe stone arch bridge at Luxemburg, Germany, hav-ing a span of 275 feet. The main arch is anapproximate ellipse, has a rise of 73 feet, andcarries 10 cross walls which support the floorsystem. There are also five semicircular approacharches \vith clear spans of 53 feet. The bridge con-nects Germantown and Roxborough, two residentialsuburbs of Philadelphia. It has a 40-foot roadway,and two 10-foot sidewalks. The entire structure issolid concrete, not reinforced, excepting in certainminor details. The surface finish is rough, some-what similar to pebble dash, but of coarser exposed sur
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Keywords: ., bookcentury1900, bookdecade1900, bookidconcretebrid, bookyear1909
