Double Curved Glu Lam Beam
Double Curved Glu Lam Beam
(OP)
Does anyone know a good source for the design of a double curved glu lam beam? The AITC Timber Construction Manual says that its design method only applies to single curved glu lam beams.






RE: Double Curved Glu Lam Beam
RE: Double Curved Glu Lam Beam
Mike McCann
MMC Engineering
RE: Double Curved Glu Lam Beam
RE: Double Curved Glu Lam Beam
RE: Double Curved Glu Lam Beam
There are a couple of things to watch for. First of all you have to check your radial tension stresses. With your beam you probably have both radial tension and radial compression. The other thing you want to check closely is your support conditions. for the glulam to behave like a curved beam one support has to behave as a roller support.
If both supports behave as pins, resisting both horizontal and vertical force, then your glulam behaves like a radial arch. Generally unless you design the system as an arch your supports will not be stiff enough to resist the horizontal thrust.
If you model the beam with a roller support you will get horizontal deflection of the beam at the roller. The stiffness of your member will determine how much horizontal deflection you will have. If the deflection is large enough you may need to detail one support as a slip connection. If the horizontal deflection is small 1/2" to 3/4" your supports may be able to tolerate the deflection with out using a slip joint. I always assumed that 1/2 the deflection occured at each support.
You should go to the AITC web site. They have a really good guide on the design of curved members with a constant cross-section.
RE: Double Curved Glu Lam Beam