Heavy timber with turn buckle beam??
Heavy timber with turn buckle beam??
(OP)
I went to this old warehouse that is now a night club. At the roof it has a dropped heavy timber every 16' spanning about 48 ft. The timber has a turn buckle (2" solid) about 26" from the top of the beam. Here is a snap shot. of the blocking holding this turn buckle underneath the beam. Has anyone dealt with this before? How do you analyze the deflection of such thing? They want to put some heavy lighting for the dance floor on this thing. Any help would be appreciated.
Not almost anymore! ![]()






RE: Heavy timber with turn buckle beam??
I would rather bolt in a frame made of tubes between the existing members that I could make stiff enough to reduce torsional deflection in the existing structure. You can sell them on it with something about it giving more versatility for lighting locations.
Congrats on the P.E.
RE: Heavy timber with turn buckle beam??
Not almost anymore!
RE: Heavy timber with turn buckle beam??
This looks like a King-Post truss, turned upside down. The truss rods, in tension, provide the support for the center reaction for the beam. But they also create an axial compression load in the beam. Hopefully, the ends of the turnbuckles are at the center of the cross section of the beam or you will have to deal with the P times eccentricity. There should be a "turnbuckle" so the truss rods can be tensioned or the beam won't have any support under the center post. Of course, the beam also has the lateral load from the roof above so you have to deal with interaction equations. From the stress in the truss rods you can calculate the deflection of the center support post.This will take a few interations to complete.
Depending on the roof loads and the low slope of the truss rods you could have one hell of a load in the truss rods.
RE: Heavy timber with turn buckle beam??
Mike McCann
McCann Engineering
RE: Heavy timber with turn buckle beam??
Mike McCann
McCann Engineering
RE: Heavy timber with turn buckle beam??
Not almost anymore!
RE: Heavy timber with turn buckle beam??
Not almost anymore!
RE: Heavy timber with turn buckle beam??
What force would there have to be in the rod for the live load and total load deflections to meet your needs - L/240, L/360? Can the connections handle it?
Mike McCann
McCann Engineering
RE: Heavy timber with turn buckle beam??
Not almost anymore!
RE: Heavy timber with turn buckle beam??
- Apply a specific force to the middle of the tie rod. The resulting mid-span deflection should indicate the amount of preload.
- Tension and mass in a long flexible member is related to fundamental frequency.
RE: Heavy timber with turn buckle beam??
Mike McCann
McCann Engineering
RE: Heavy timber with turn buckle beam??
Not almost anymore!
RE: Heavy timber with turn buckle beam??
Have you measured the current deflection, under the load you can see and estimate?