roof diaphragm and building expansion joints
roof diaphragm and building expansion joints
(OP)
We have a large building that will require an expansion joint. There are also plans to add on in the future, creating another expansion joint perpendicular to the first. If everything is built we would have a building split into four quadrants by the expansion joints. Has anyone done a roof diaphragm only supported on two perpendicular sides?
Client is resistant to bracing and contractor does not like the cost of moment frames. Looking at ways of making both happy.
Client is resistant to bracing and contractor does not like the cost of moment frames. Looking at ways of making both happy.






RE: roof diaphragm and building expansion joints
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: roof diaphragm and building expansion joints
With the joints you have to include additional braces or brace systems.
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RE: roof diaphragm and building expansion joints
RE: roof diaphragm and building expansion joints
Can't you brace the expansion joint and tie the diap. into the lateral system along that joint?
RE: roof diaphragm and building expansion joints
We will provide bracing or a frame. Problem is a design-build client that will want to keep things as open as possible for the owner and a design-build builder who will resist the cost of a frame and associated foundations.
RE: roof diaphragm and building expansion joints
At the expansion joint, we used a Chevron brace (upside down "V") to minimize the braces interruption of space usage below. You might also look at eccentric braces of some kind to keep the diagonal braces as vertical as possible to further minimize its effect on the spaces.
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RE: roof diaphragm and building expansion joints
1) joist girder moment frames on some or all framing lines in one direction.
2) A single braced line perpendicular to the moment frames (shear wall or braced frame).
Fundamentally, this is a permutation of the three sided building concept which many engineers despise and some will reject out of hand. It would have the following advantages however:
1) open space is preserved.
2) minimal impact on foundations etc because overturning resistance is distributed.
While this may not ultimately be the best path to take, sometimes it's good to have an innovative solutiion in your bank pocket just to show that you're willing to play ball. Optics.
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: roof diaphragm and building expansion joints