A series of bridge spans built on equally spaced pile bent foundations. Typically measuring +/- 10’ for Pedestrian Bridges and +/- 15’ for Vehicular Bridges, however, the span dimensions will ultimately be determined by the design & engineering requirements for the proposed bridge live load (i.e. who and what will be using it). In addition, you’ll find that repetitive span bridges are designed with standard dimensional lumber or rough sawn timbers.

A single bridge span built with rough sawn timber between two abutment foundations. The term ‘short’ is in reference to the timber stringer structure which limits lengths to 26’ or less.

A single bridge span built with Glue Laminated Timber between two abutment foundations. Due to the use of Glue Laminated Timber for the structural bridge stringers, single spans are able to stretch up to 100 linear feet with greater lengths reviewed on a case by case basis. The most economical length would be around 80 linear feet. The term “Free” is in reference to the large clearance that can be achieved between abutment foundations. Typically, a Free Span is selected for lengths greater than 26’ that require or are best without any impacts within the crossing environment. Although Free Spans have been used for shorter spans that would benefit from the aesthetic or strength that Glued Laminated Timbers inherently provide.

The standard multiple span uses one longer free span section, usually over the main water channel, with shorter, repetitive span approaches. A single bridge can include many variations like repetitive span, short span, and free span sections to achieve the best-case scenario for the client, use, and environment. A Multiple Span bridge can utilize dimensional lumber, dimensional heavy timber, and Glued Laminated Timber, as it pertains to the designed spans. One of the most common uses for a Multiple Span bridge is to reduce the overall length of a Free Span to facilitate the required clear and utilize Repetitive Span approaches for the remainder of the length, providing feasibility in construction techniques and client budget.