Page:Final Report - The Columbia River Interstate Bridge.pdf/41

 so that the forms would be duplicate and interchangeable. and these were used repeatedly.

The details of every part were simplified with the most careful attention so as to make the manufacture and fabrication with as little complexity as possible, with the result that the steel work as delivered, both from the shops of the American Bridge Company and the Northwest Steel Company, was in excellent condition to be readily erected, properly fitting in every part. 50 accurately was the work of the American Bridge Company for the Columbia River trusses carried out that in driving the 17,000 field rivets in the first truss span there were found

only six rivet holes which had to be corrected in any way for the entrance of the rivet, and other spans were of the same general character. The same care of detailing and duplication of parts will be found in the machinery for operating the lift span and even in such details as the framing of timbers for the bases of the piers. The concrete floor slab was placed in just the position so that the reinforcing bars could be laid down on the steel cross beams and need no other support.