Jack Nixon

With his father working as Roebling's Chief Draftsman, Jack grew up hearing about the great bridge projects. At 19 he joined Roebling as a laborer, became an apprentice draftsman and then an engineer. Father and son worked together for twenty years.

On the George Washington Bridge: In 1927 they started the Geoge Washington Bridge. They had to make the wire for this huge bridge which was going to be a world record both in size and length and total amount of material. Roebling's Chief Engineer at that time was Charles C. Sunderland. I remember my father would have to go to the Bridge and look at some of the machinery they had designed here in Trenton. He was the Chief Draftsman. He worked for Roebling for about 30 years; he developed a number of things and had several patents.

On the small suspension bridge connecting two of the Roebling buildings on Broad Street: Sunderland brought the idea of prestressed concrete to this country. To develop that, the Roebling Company decided to build this small experimental bridge. Those little slabs are where they tried some pre-stressed work. They put the stiffening in it, the little stiffening cables. The next one in the series is the Lumberville Bridge over the Delware River. Sunderland finally convinced them to build the Walnut Lane Bridge in Philadelphia, which is the first pre-stressed concrete bridge in the country. That was all Roebling strand and a Roebling concept.

On maintaining bridges: Corrosion is the big problem with the old suspension bridges. The oldest one is the Brooklyn Bridge. On that, the suspenders were corroded badly in places. We had to take all the suspenders and cable bands off and replace them. Amazingly enough, Washington Roebling made a decision to put galvanized wire on the Brooklyn Bridge which was unheard of in those days. So the main cables of the Brooklyn Bridge are in pretty good shape; they have not corroded.

On working on suspension bridges: I always feel thrilled working on a suspension bridge. One of the best memories I have is of working on the Tacoma Bridge. I was in charge of strand adjusting, so every night I had to walk across the bridge and come back across the footwalks. I think the most beautiful sight would be when the sun was coming up. I was just walking off the top of the tower down the footwalk and and I could look across and see Mt. Rainier. It was just beautiful, never anything more spectacular.

I've always enjoyed my work. I've often said that if they would have let me work on the Brooklyn Bridge for nothing, I would have done it. It's just a great experience to be part of a group which erected a big, monumental bridge.

On John A. Roebling: The genius was John Roebling. He made these big cables. Everybody up to that time tried to make suspension bridges out of putting smaller ropes across and they all blew down. Look at the stays he put on the Brooklyn Bridge. That's what has really kept that bridge still over the years. And the other thing that is really amazing is the spinning of the cables. This spinning process has changed litte since Roebling used it on the Lackawaxon Bridge around 1850. We do it faster now and over greater distances, but the system hasn't changed.

On building suspension bridges: First an engineer has to decide what the requirements are, what kind of load is going to go across, how many lanes. The next thing is to look at the ground to see that there will be good footing. He has to have a good base for a suspension bridge, or the achorage will slide. The next thing is to do the under-ground work. On many of these bridges, there's almost as much work underground as there is above ground. For instance, on the Tacoma Bridge, the piers are in 150 feet of water. You have to get below that, dig it out and get piers into place. Then the anchorage itself, at the ends where the cable is tied to hold the bridge up, is a massive piece of concrete that has to have a lot of weight to it, yet not too much so that it will sink. On the Walt Whitman Bridge, they had to spread it around because the ground was soft.

The next operation is to get the towers up; they are big steel supports. There are big design problems to make sure they fit together properly, and very fine machine work to be sure that all the joints go together, especially when you are making something 800 feet high. Then the next step is to calculate the weight you're going to put across that bridge, what the span is and being sure the truss is stiff enough. Then you start to erect it, to put the cables across. There's a lot of checking you have to do to be sure the cable is in the right position as you put it across so the bridge will be where you want it when you are finished. That cable is going to support the roadway, so you have to have connections (suspenders) between the main cable and the roadway. There is some adjustment to do, but principally you have a suspension bridge and you're finished.