AASHTO Journal - AASHTO Updates Pedestrian Bridge Design Guide

The American Association of State Highway and Transportation Officials recently published the second edition of its “LRFD Guide Specifications for the Design of FRP Pedestrian Bridges,” specifically for the load and resistance factor design (LRFD) needs of walkway structures made from fiber reinforced polymer (FRP).

[Above image by AASHTO]

FRP is a composite material made up of a polymer matrix reinforced with glass that is known for its exceptional strength-to-weight ratio, corrosion resistance, durability, and design flexibility. Its light weight and flexibility make FRP structures easier to assemble and last longer in specific cases, such as pedestrian bridges.

Originally published in 2008, AASHTO said it intended the initial version of this FRP bridge design guide to focus solely on FRP truss structures made by bolting pultruded elements together. Over the course of the last 17 years, however, pultruded FRP planks and vacuum infusion molded FRP panels have been used as bridge decking supported by steel, concrete, or timber beams – design provisions based on Allowable Stress Design (ASD) and Load Factor Design (LFD) calculations.

Thus, the second edition now provides broader guidance for FRP-only bridges as well as structures built with several materials, including FRP. Also, because those design provisions are based on LRFD formulas, this updated publication offers supplemental information from AASHTO’s “LRFD Bridge Design Specifications, 10th Edition,” issued in December 2024, as well.

The emphasis of these updated guide specifications is on delegated design, where the manufacturer is responsible for the design of FRP pedestrian bridges using performance specifications and requirements specified by the designer/owner. The manufacturer is also responsible for designing and detailing connections to fit with the FRP decking or bridge system, AASHTO said.

To order a copy, visit the online AASHTO Store and search by the item code – GSDFPB-2 – or click here for a direct link to the publication’s AASHTO Store homepage.