Precast Sound Walls

[WpgKarl]

Does anybody out there have any recommendations for the design of precast sound walls (the kind used to isolate residential areas from freeway vehicle noise)?

Typically, I have seen precast columns sitting on CIP piles, with the columns notched to receive a drop-in precast panel in between each column.

I am wondering about potential problems with the panels moving around, when you have a very long stretch of wall (say several miles long) and the temperature varies over summer to winter. Walls could move around too much if they are too loosely connected, and they can do serious damage to the columns if expansion is restrained...

PS - If you haven't guessed it by now, I work as a design engineer for a precast manufacturer. Although I did also spend 4 years in structural consulting, so I do enjoy reading the other threads!

PPS - JAE - you're awesome! Too bad you don't work in the office right across from me, but with this site it's the next best thing.

 

[hokie66]

Wouldn't the state highway departments have standard designs for sound walls? There are a lot of them around, and you wouldn't want the reinvent the wheel. But I think you are right to be concerned about the corners of the columns.

 

[Dinosaur]

You probably already know that the design of these are governed by the AASHTO Specification for Sound Barrier Walls.

Since the post spacing is usually limited to 24 ft or less, the amount of expansion in a given panel is pretty small. If you are concerned, I would detail the post flange with a generous value to permit a good overlap with the panel edge. If the flange extends 6 inches away from the web and there is a half inch between the end of the panel and the web of the post, everything should be fine.

There are a number of other wall systems that use steel posts attached to concrete foundations and even steel posts set into augered holes and backfilled with concrete. In these systems, I am most concerned about post deflection and bracing against lateral torsional buckling.

Good Luck.