Wood Truss 3

[ketur]

I am evaluating some 70 year old wood trusses that span 60 feet and are spaced 20 ft. top and bottom chords are 10" x 10". Tension splice in bottom chord consists of 1/2" steel plates with 1" lugs (one lug per plate on each side of joint). The design tensile force is 55000 lbs. In addition to steel plates it looks like there some kind of dovetail. Can anyone suggest some reference material which deals with this type of connection?

 

[jheidt2543]

I'm involved in a very similar investigation and the connection you describe is a very common one for heavy timber trusses. Here are some of the references I'm using:

"Wood Engineeering and Construction Handbook"
by Keith F. Faherty and Thomas G. Williamson, 2nd Ed., 1995

"Timber Constrution Manual"
by AITC, 2nd Ed., 1974

"Structural Members and Connections"
by Hool and Kinne, 2nd Ed., 1943

"Steel and Timber Structures"
by Hool and Kinne, 2nd Ed., 1942

"Handbook of Building Construction"
Edited by George A. Hool, 1924

"Structural Details or Elements of Design in Timber Framing"
by Henry S. Jacoby, 1st Ed., 1918

 

[Stress02]

Everytime I have been involved in an anchient truss, there are indications of bottom chord tensile failure and I end up adding tie rods as the tension member.