aashto 16th edition

[bjb]

We are looking at a pedestrian bridge and have obtained the Guide Specifications for Design of Pedestrian Bridges from aashto. This document references the 16th edition of the Standard specifications for Highway Bridges, which we are unable to locate. We do have an in-house copy of the 15th edition, and are prepared to order the 17th edition.

My question: are there significant changes between the 15th, 16th and 17th editions?

 

[jimaitken]

bjb

I think that it depends on the particular section you are looking at. Here is what I can recall about the changes. Keep in mind I am speaking only from the sections I deal with the most concerned mostly with bridge design (steel and concrete) so I cannot speak for every section in the Specs.

Chapter 14 Bearings, changed significantly between editions and even during interims in the 16th edition.
The seismic specifications also changed between the 15 and 16th, but the bread and butter stuff such as loading, concrete, and steel design remained relatively unchanged.

The answer to your question though is that the 17th edition is a complete and FINAL version of the Standard Specifications. AASHTO is not going to update this Spec because it is trying to move designers and DOTs to LRFD design. They are only going to issue updates to the LRFD Specs so the 17th edition is really the final revison of the 16th. By this logic if you use the 17th edition you are using the 16th. You would be correct to use the latest edition for your ped bridge.
Does that make any sense?

 

[bridgebuster]

I just completed the design of a third ped bridge using the Guide Spec and the 17th Edition; don't worry about locating the 16th Edition.

One key element of the Guide Spec is the vibration analysis. The spec also provides a good example for the design of a pony truss

 

[bjb]

Thanks for your replies. We will get the 17th edition.