3 resultados para Highway-railroad grade crossings
em CaltechTHESIS
Resumo:
The problem of the Atchison, Topeka, and Santa Fe railroad in Pasadena is a very dynamic one, as is readily recognized by engineers, city officials, and laymen. The route of the railroad was first laid out in the eighties and because of certain liberal concessions granted by the City of Pasadena, the right-of-way was located through Pasadena, despite the fact that the grade coming into the city either from Los Angeles or San Bernardino was enormous. Some years later, other transcontinental routes of the Santa Fe out of Los Angles were sought, and a right-of-way was obtained by way of Fullerton and Riverside to San Bernardino, where this route joins the one from Los Angeles through Pasadena. This route, however, is ten miles longer than the one through Pasadena, which means a considerable loss of time in a short diversion of approximately only sixty miles in length.
Resumo:
An article in the Engineering News-Record for March 30, 1923, describes a new concrete arch bridge across the Connecticut River between Springfield and West Springfield, Mass.
Resumo:
The span of the bridge was assumed as 100 feet. The type of bridge used is the timber Howe Truss. The height of truss was taken as 20 feet between center lines of top and bottom chords. The width was taken as 18 feet center to center of trusses. The truss was divided up into five panels 20 feet long.
It was designed according to the "General Specifications for Steel Highway Bridges" by Ketchum. For the live load for the floor and its supports, a load of 80 pounds per square foot of total floor surface or a 15 ton traction engine with axles 10 feet centers and 6 feet gage, two thirds of load to be carried by rear axles.
For the truss a load of 75 pounds per square foot of floor surface.
For the wind load the bottom lateral bracing is to be designed to resist a lateral wind load of 300 pounds per foot of span; 150 pounds of this to be treated as a moving load.
The top lateral bracing is to be designed to resist a lateral wind force of 150 pounds per foot of span.
The timber to be used in the bridge is to be Douglas fir.
The unit stresses used for timber are those of the American Railway Engineering Association.