American Bridge Co. testing Army gun containers

When I first wrote this article, I had only the first two photos below. But now I have a third, and there's more information about this American Bridge project written on its back, so see the update below.

 I don't know more about this American Bridge Co. project than the notes written on the back of these two press photos.

If you know any additional details about the project, please leave a comment.

This is the press note on the back of the first photo below:

"U. S. Army containers. Made by the American Bridge co. being tested on the Ohio R. These containers are made to keep guns dry."

Testing Army gun containers on Ohio River
American Bridge Co.
Ambridge
January 7, 1946

Testing Army gun containers on Ohio River
American Bridge Co. 
Ambridge
January 7, 1946

That's the still-standing historic Ambridge-Aliquippa Bridge in the background of the photos above.

Update July 15, 2017, another photo, more information:

Final test of ammo containers
American Bridge Co.
Ambridge
January 11, 1946

Here what the back of the photo above says:

The final test for Army storage cans, Pittsburgh, PA.--Big cans, designed for the Army as protective containers for preserving Army equipment, went through the final test of their efficiency and came through successfully. As a test of waterproofness, they were dunked in the Ohio River, near Pittsburgh, and proved to be watertight. The loaded cans can be tossed overboard in places where there are no dock facilities, and be towed to shore by smaller boats or allowed to wash ashore. Photo shows: After the test, the can is loaded back on the flatcar on which it traveled 6300 miles from Pittsburgh to the West Coast and back, to test its endurance in all climates. 

If you look closely, you can see a bit of the Ambridge-Aliquippa Bridge in the background of this photo too.