UFC 4-023-03 Progressive Collapse
UFC 4-023-03 Progressive Collapse
(OP)
Is anyone familiar with the Unified Facilities Criteria for Progressive Collapse?
I have a question on the tie force method in section 3-1. It says that you must demonstrate that the elements are able to withstand the required tensile tie forces while undergoing a rotation of 0.2 RAD. How would you go about calculating the tensile capacity of a beam while it's rotating 0.2 radians at it's supports?
My guess is that you must have the connection already detailed and then calculate the forces in the bolts under a rotation of 0.2 radians in the connection. And then add to those stresses the stresses from the axial force from the beam. Actually this procedure makes sense after typing it. Does anyone know a proper method for achieving this?
I have a question on the tie force method in section 3-1. It says that you must demonstrate that the elements are able to withstand the required tensile tie forces while undergoing a rotation of 0.2 RAD. How would you go about calculating the tensile capacity of a beam while it's rotating 0.2 radians at it's supports?
My guess is that you must have the connection already detailed and then calculate the forces in the bolts under a rotation of 0.2 radians in the connection. And then add to those stresses the stresses from the axial force from the beam. Actually this procedure makes sense after typing it. Does anyone know a proper method for achieving this?






RE: UFC 4-023-03 Progressive Collapse
RE: UFC 4-023-03 Progressive Collapse
At the end of the day though I think it would seem easier to just add rebar in the slab as ties rather than get fancy with the steel connections. Also, I'm assuming that you can use the metal deck as the tie force as long as the panels are welded together properly in lieu of reinforcement.
RE: UFC 4-023-03 Progressive Collapse
.2 radians is 11.5 degrees. A really big rotation. You're not going to get any bolted connection to work. They're trying to push you to using the reinforcing in the slab as the ties, as you stated. Look at figure D-4 on page 123.
The days of using your primary structural elements as ties are over.
RE: UFC 4-023-03 Progressive Collapse
RE: UFC 4-023-03 Progressive Collapse
I've attached the new version that I've been working off of. It does state in section 3-1.3.1 that you can use the structural members (beams, girders, spandrals) to resist the tie forces if their connections can undergo the 0.2 rad rotation while taking the tie force.
In 3-1 though it states that this must be approved by a 3rd party engineer.
RE: UFC 4-023-03 Progressive Collapse
h