When a crack began to appear in the $4.5 million wall that stabilizes the bluff below Clifton Avenue, City Engineer David Gardner wasn’t worried at all. That’s because he said the crack is supposed to be there.

Called an expansion joint, the man-made crack was designed in the wall to allow for movement, Gardner said. He compared the expansion joint to planned cracks in a sidewalk – it gives the wall &uot;breathing room.&uot;

&uot;If it wasn’t cracking I’d be worried about it,&uot; said Gardner, who first noticed the crack about three months ago.

The problem is that when Hayward Baker Construction Co. finished the wall by spraying it with concrete, workers covered the expansion joint.

So when movement did occur in the wall – movement that could have been as slight as an eighth of an inch – a crack began to form in the thin layer of concrete, Gardner said.

But now that the crack has grown, Gardner said he’s been getting phone calls from local residents concerned about whether there’s a failure in the wall.

&uot;I’ve reassured them there’s nothing to be concerned about,&uot; Gardner said.

But that doesn’t necessarily mean the crack will continue to look as it does.

The U.S. Army Corps of Engineers, which adminsters the federal and state grants which paid for the bluff project, will ask contractor Hayward Baker what it can do to make the wall look better.

Gardner said the expansion joint probably should not have been sprayed with concrete.

Whatever work Hayward Baker has to do to fix the crack will be covered under its warranty, Gardner said, so it won’t cost the city or the Corps any money.

Gardner said the problem was minor compared to the work done on the project.

&uot;Hayward Baker did a wonderful job on that wall,&uot; Gardner said. &uot;One little flaw at the end doesn’t affect that.&uot;