On 03/07/2019 20:14, Sus wrote:
I have a simple square pergola in my backyard.Â* It's made of 6" x 6" beams
that are lap jointed.Â* I want to hang 2 swings on each of the two
beams.Â* Is
there a weight restriction given they have lap joints? the swings would be
wooden and be able to hold an adult.

It depends on how tightly the bolts are done up. Are there star washers
in the lap joints? And nice big washers on the outside, to stop the nuts
and bolt heads sinking into the timber.

Is there any diagonal bracing? If not, you might find it tends to go
parallelogram shaped especially with adults swinging vigorously.

It also depends on how long the beams are, but I'm guessing it's a
normal sort of size. Also, are the uprights set into concrete or
metposts, or just standing on paving slabs?

Also, I am confused about what you mean about having two swings on two
beams. Do you mean two parallel beams? Presumably this means the
perpendicular beams are quite long, to prevent clashing? And if it is
square, this means the cross beams must be quite long too.

The strength will also depend on the type and quality of the wood, but I
have probably asked enough questions already. And I've probably missed a
few.