National Steel Bridge Alliance
Continuous Span Standards
The Continuous Span Standards serve as a guide to state, county, and local highway departments in the development of suitable and economical steel bridge superstructures. Included are 88 unique solutions for 3 span bridges with center spans between 150'-0" and 300'-0", girder spacings between 7-'6" and 12'-0", and plate girder designs utilizing both homogenous and hybrid steel options. These solutions were developed using the latest version of the AISC/NSBA LRFD Simon software v10.2 with the input files provided as part of the download.
The Simon input files were provided because the NSBA understands bridge span arranges almost never match an idealized solution (ends span lengths at 78% of center span length). In providing the files, the NSBA has integrated two of it's most successful resources into one powerful preliminary design tool. Find a span arrangement that most closely matches the bridge's geometry and begin editing from that file. This saves time and allows for more exploration of girder depths and steel strength options.
Included on each conceptual solution are tables presenting girder plate sizes, diaphragm spacings,intermediate stiffener sizes and locations, shear connector spacings, camber, and girder weights.