Design Guide for Ladder Deck Bridges

The ladder deck form of construction for highway bridges is currently a popular and economic choice – this publication offers practical design guidance.

This publication provides design guidance on a particular form of composite highway bridge, the so called ladder deck form. Ladder deck form has two main girders, spanning longitudinally, and multiple cross girders spanning between the main girders; the deck slab spans longitudinally between these cross girders.

This particular configuration gives rise to design issues that differ from the multi girder form of construction covered by the two SCI publications Design Guide for Composite Highway Bridges (General Guidance and Worked Examples). This publication is complementary to the earlier publications.

Guidance is given on initial design of ladder deck bridges, covering the reasons for choosing this form, the selection of configuration and the initial sizing. Advice is given on the application of the design rules, according to BS 5400.  Guidance on the design of cross girder connections and some aspects of detailing is also provided.

Three short worked examples of design calculations are included.