GB403495A - Improved manner of construction of bridges of standardized members - Google Patents

Abstract

403,495. Bridges. EVERALL, W. T., North Western Railway, Moghalpura, Lahore, Punjab, India. Oct. 3, 1932, No. 27457. [Class 20 (i).] A bridge, girder, or truss of variable span of the type described in Specification 228/86, [Class 20, Buildings &c.], is built up of standardized members each of such length and dimensions as to be easily transportable, similar members being used in either the booms or web members so as to be interchangeable and to form isosceles triangles so that the boom members abut at their adjacent ends. The system is applied to either " throughspan " or " deck-span " bridges, and for bridges of great length, parts are duplicated to increase their strength. The standardized parts described are channel-section bars and extensions, gusset plates, and built-up struts. The upper and lower booms of the girders are similar and are each formed of a series of channel-bars 1 with ends of members abutting and connected by gusset plates 7, and arranged with their flanges towards each other as shown in Fig. 16, the channel-bars being connected by cross plates 2. Similar channel-bars, cross connected, are used to form the diagonal connectors 5, 6, between the upper and lower booms, and suitable clearance is provided by the gusset plates between the ends of the diagonal connectors and the boom bars so that the triangulation is isosceles. Where the span exceeds a certain number of bays, the booms for a certain portion of their lengths may be doubled by connecting bars back to back, as shown in Fig. 17, and cross connecting them by standardized drilled connectors 14, Fig. 15 ; the diagonal connectors between the booms may also be doubled as required and as shown in heavy lines at the right end of Fig. 1. The booms on each side of the girder are connected by similar standardized channel-bars 24 of the same length, assembled with their flanges pointing away from each other, and to provide a wide deck these may be joined by standardized connectors 25, so as to protrude beyond the booms, where they support moulded gutter plates 29, the decking, and the side rails 30, Fig. 2. Suitable diagonal bracing may be used between the girders. For a " through-span " bridge, Fig. 12, certain of the transverse connectors may be provided with extensions 32 to carry built-up bracing members 33, 35, secured to the upper booms at 36, and for long-spans in this type of bridge, K-bracing 38, Fig. 13, may be used in the end bays of the bridge.