Nailed Moment connections in wood
Nailed Moment connections in wood
(OP)
am tryign to setup a spreadsheet or a matlab program that will "design" scab reiforcement for trusses members. The webs seem straight forward and where i am running into questions is with chords. I am wonderign if 1. there is some guide or reference manual i can use to help guide me through this, if not, then 2. how do i design nailed connections for moment transfer.
I see that in most of the steel design manuals they show how to do an elastic design of groups of bolts for an eccentric load. Since a moment is just an eccentric load i am wondering if it is acceptable to do a similar type of analyis for a nailed connection (most difficult part is to assume and determine where the nails will be located). Any thoughts out there on this?
I see that in most of the steel design manuals they show how to do an elastic design of groups of bolts for an eccentric load. Since a moment is just an eccentric load i am wondering if it is acceptable to do a similar type of analyis for a nailed connection (most difficult part is to assume and determine where the nails will be located). Any thoughts out there on this?





RE: Nailed Moment connections in wood
RE: Nailed Moment connections in wood
By the time you got enough nails into the wood member, the strength would be seriously compromised.
Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask
RE: Nailed Moment connections in wood
Garth Dreger PE
AZ Phoenix area
RE: Nailed Moment connections in wood
The connections had a crapload of nails in them and still barely survived erection, jacking up the deflected roof by hammering the truss into the gap.
I don't think a nailed truss is a good idea under any circumstance. I wouldn't have done it at all, except that the owner's wife was getting hysterical about keeping the looters out.
Mike Halloran
Pembroke Pines, FL, USA
RE: Nailed Moment connections in wood
When I was in that world - they were not - although some conservative estimates did seem to test out OK. But never really put into practice.
RE: Nailed Moment connections in wood
Garth Dreger PE
AZ Phoenix area
RE: Nailed Moment connections in wood
By using so many nails in a plywood plate, you are inhibiting the ability of the wood members to shrink perpendicular to the grain, and thus encouraging horizantal cracking of the member at the connection, weakening any moment resisting ability as time goes on. To prevent this, the connection would have to be very carefully detailed with this in mind.
Plus, with the use of plywood scab plates, you cannot rely on the full thickhness of the plywood for the nailing values. Not the same as solid lumber or metal side plates.
Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask
RE: Nailed Moment connections in wood
I agree with you and even worked on quantifying those numbers MANY years ago.
I just have never heard of any really good results - or maybe the truss plate mfgs keep that info to themselves - as I probably would.
RE: Nailed Moment connections in wood
What do you call the APA Narrow Wall Bracing detail?
RE: Nailed Moment connections in wood
Read the response...."in general" means in most instances...there are no nailed moment connections in wood.
Can other conditions be designed? Of course...connections can be designed to withstand/transfer moment...but that is rather rare for wood frame construction.