File:Design of a plate-girder railroad bridge (1913) (14757697901).jpg

Identifier: designofplategir00bunn (find matches)
Title: Design of a plate-girder railroad bridge
Year: 1913 (1910s)
Authors: Bunn, Nixon Lawrence
Subjects: Plate girders Railroad bridges Theses
Publisher:
Contributing Library: University of Illinois Urbana-Champaign
Digitizing Sponsor: University of Illinois Urbana-Champaign

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oth sides ofthe river. To overcome the difficulties of having submerged tracksat the time of over-flow the roadbed is built on a fill nine feetabove high water about eighteen feet above the average surface ofthe ground. The tracks approach the bridge at both ends on a plus0.7 percent grade until within a half mile of the structure wherethey are level. The river at this point is about 550 feet wide when the streamIs at mean water level. The depth of the river is moderate not be-ing over 18 feet; and this.occurs only under one span, the averageepth being abov^, 10 feet at mean water level. I Art. 2 Description of Old Bridge.The old bridge Fig. l,,was a through truss of five spans andj rested on masonry piers and abutments. The spans were of the follow-!j lengths: 111 feet - 5 inches, 10-3 feet - 11-3/4 inches, 103 feet - j; 113/4 inches, 99 feet - 9 inches, and 111 feet - 5 inches making a i total of 530 feet - 6-l/s inches.I The superstructure was of the Pratt type, each truss contain-
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-ing seven panels. The height was 22 foot and tho width ,ris 10 footcenter to center of trusses. The tops of the piora were 2< foot long and 6 foot - 11 incheswide. The piers rested on-wooden piles the tops of v/hich were seven Ifeet below the bod of the stream. Tho height of tho piers was about25 foot making it 18 feet abovo mean water level. Fig. 2 gives thedimensions as stated abovo. L P U ffi 1 HI - 5 1. los-nl 1 i\t-s r Fig. 2. Plan and novation of the Old Bridge. Art. 3 Reasons for Replacement.The bridge was thirty years old when torn down; and before thistime several weak places had been found in the structure. The piershad been repaired several times, and the steel work was begining toshew signs of deterioration. A slow order for trains had been on-forced for quite a while. However, it was not these facts alonethat caused the replacing of the old structure. As time goes on, progress increases and new and more modern methods are introduced,methods One of these^was the introd

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