Moment frame installer in Orange County
A moment frame is what lets a house open up. Take out a wall and the building loses the thing that kept it from racking sideways in an earthquake. A moment frame puts that resistance back with steel: two columns and a beam, joined into rigid corners that cannot rotate. The frame carries the sideways load through those welded corners instead of through a wall, and you get the twenty foot glass opening the architect drew.
The word moment is engineering for bending. In an ordinary bolted post and beam connection the corner can hinge a little, and the frame folds like a parallelogram. In a moment connection the corner is welded so it holds its ninety degrees, and the steel itself has to bend before the frame can move. That is why these connections are welded, why a special inspector looks at them, and why the welding matters more here than almost anywhere else in a house.
In practice the job runs in one order. The engineer sizes the frame and details the connections. The concrete gets poured with the anchor bolts and any embeds in the right place. The columns get set and plumbed, the beam goes on, and the corner welds are made in the field, in position, usually overhead or vertical with no room to stand back. Then the inspector checks the welds. Only after that does framing close it in. A weld that gets covered before it is inspected gets uncovered.
What that includes.
- Ordinary and special moment frames, residential and light commercial
- Frames set to the engineer's drawings, plumbed and shimmed
- Field welded moment connections, made in position
- Anchor bolt and holdown layout checked against the plan before the pour
- Retrofit frames dropped into a standing house for a wall that is coming out
- Inspection timing coordinated so nothing gets closed in early
Questions we get on this one.
What do you need to price a frame?
The structural sheets and the frame schedule. Member sizes, connection details, and the height are what set the number, and the access to the opening is what sets the labor. Send the set and you get a real price. We will tell you when you will have it rather than guessing at a turnaround.
Do you fabricate the frame as well as set it?
Either way. Doing both is usually cheaper and always simpler, because a fit problem is ours to fix rather than a conversation between two subs on your job. If the frame is already bought, send the shop drawings and the delivery date and we will price erection on its own.
Can the frame go in after the building is framed?
Often yes, and a lot of our retrofit work is exactly that. It costs more than doing it during the shell, because things have to come apart and go back and the access is worse. If it is still in design, put it in early.
Who inspects the welds?
A third party special inspector, hired by the owner rather than by us. Moment connections are almost always on the inspection list in the plans. We schedule around that inspector so they see the weld while it is open, and you are not pulling drywall off in three weeks.
This is licensed work. OC Mobile Welding LLC holds CSLB C-51 #1157116, C-51 Structural Steel, current and active. Working out of San Clemente, CA.