[SIZE=10.5pt]Hi,[/SIZE] [SIZE=10.5pt] [/SIZE] [SIZE=10.5pt]I'm looking for information regarding the use and manufacturing of Callender-Hamilton Truss Bridges (C-H) during WW2. [/SIZE] [SIZE=10.5pt]The C-H system was design by Archibald Hamilton prior to WW2 and from what I understand Bailey has violated Hamilton's copywriters in his design (although the Bailey bridges are an improvement, mainly in construction time and simplicity). I know C-H bridges were vastly used during the war.[/SIZE] [SIZE=10.5pt]It would also be interesting to know how many war-time C-H bridge are still around - I know of a couple in Europe from my Google search. [/SIZE] [SIZE=10.5pt] [/SIZE] [SIZE=10.5pt]We have a Callender-Hamilton Truss Bridge in the Haifa Bay in Israel. Since the Bridge has several steel sources we believe it is WW2 surplus. The C-H bridges I found on-line are all galvanized but ours isn't (would love to know why). It also has vertical truss elements in a double truss which from what I understand is unusual. [/SIZE] [SIZE=10.5pt] [/SIZE] [SIZE=10.5pt]Cheers,[/SIZE] [SIZE=10.5pt]Uri[/SIZE]
While I'm not familiar with this particular type of bridge's history, I can say the reason things weren't galvanized back then would be the time and cost of doing that. To either hot dip or electroplate zinc onto a steel component would have required the steel to be sand blasted clean to bare metal, cleaned, then treated in a dip tank to the zinc plate. All of that would have required considerable facilities and manpower to accomplish as well as slowing down production. I would assume at the time (WW 2) that usable production was considered far more important than longevity of the material. Consider, that aircraft were often expected to last just 100 operational hours at most. A bridge is hardly something they were looking at lasting more than a few years, if that.
I must admit I've never heard of this type of construction. Out of curiosity I did some searching. I came across this site which might have some of the information you're seeking. http://structurae.net/structures/bridges-and-viaducts/callender-hamilton-bridges Here is a site that lists Callender-Hamilton Truss bridges still in use in New Zealand. Interesting stuff. https://www.google.com/search?q=callender-hamilton+bridge+still+extant&ie=utf-8&oe=utf-8
from all I've read to date, CH bridges were galvanized so they can be assembled and disassembled easily - since the main idea was temporary construction. there are several examples online of war time CH bridges still standing that were galvanized. the New Zealand article that Lou mentions (https://www.ipenz.org.nz/heritage/documents/Baker,%20Molcsan%20and%20Buchanan%20paper%20(380%20KB).pdf) is one of the best sources of information I found. that paper also indicates that they were fabricated galvanized. Uri