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A lot of the updates and amendments that have been incorporated into the LRFD spec were the contentious or controversial issues that were more or less put off for a later date while states clung to the Standard Specification. I think there will be a continuous stream of interim revisions now...

As far as how widespread LRFD is, I would venture to guess 100% for Federal Aid projects. Although I think FHWA is allowing some wiggle room for states in that if 'design' has begun it can be carried through using the original code. That can leave a wide interpretation as to when 'design'...

If you're concerned about weak-axis bending of the double top plates between the studs why not add a segment of dimension lumber strong-axis below the top plates? This can act as a T-section if you will and bridge to the nearest studs to transfer the vertical load. It won't interfere with...

I just purchased the NDS 2005 which is a combined ASD/LRFD document similar to the AISC approach. The document is clear and concise and phi factors are added to the design tables for those who use the LRFD approach. Deflections are indeed addressed in the document. The IRC prescribes limits...

Is that the Extreme Stupidity I or II limit state?

I'm a little lost too. Are you referring to a cast-in-place superstructure such as a T-Beam or are you referring to deck construction? I didn't know anyone was still doing CIP with mild steel except for the smallest of stream crossings. Prestressed members are standard fare 'round here.

Has anyone started working with the AASHTO 2005 LRFD Interim Revisions? Section 5.7.3.4 has changed in that the Z parameter is no longer used for crack control in concrete. There is now a gamma factor that controls the spacing of reinforcing. I'm using a gamma factor of 1.00 for Class 1...

The reason that you're seeing higher, thicker (and subjectively more unattractive) barrier rails has to do with NCHRP 350. This report dictates the different Test Levels (TL's) which are required for barriers based on ADT, traffic and roadway characteristics, and design speeds. For example...

This gentleman has an outstanding spreadsheet for plotting shear and moment diagrams for multiple axles and continuous spans. http://www.umoncton.ca/turk/logic.htm This may come a little late for use in your project based on the original posting date but others may find it useful.

Did they give any idea as to the cause? Was there a collision with the pier or large temperature change?

Thank you for your thoughts. There is widely varying opinion on the function/necessity/behavior of these approach slabs. What we are aiming for is a longer, more heavily reinforced approach for interstate-quality roadways and a shorter, more economical version for low volume bridges. As far...

I am curious to know others' thoughts on the design of bridge approach slabs... I have been looking through some materials and there are a variety of techniques used to determine the reinforcing in the slab. Some examples have treated the approach slab as a simple span from the backwall to the...