Site Cast "Precast" Beams and Planks
Site Cast "Precast" Beams and Planks
(OP)
I have a project that is somewhat of a training facility for university-level construction students. The facility will be constructed/deconstructed twice annually. I have been asked to design concrete beams and planks that will be "precast" by the students on site and then lifted into place. Spans are less than 14' and standard grade 60 reinforcing will be used.
It seems like a pretty simple task, but are there any nuances to designing a "precast" member vs. true CIP?
It seems like a pretty simple task, but are there any nuances to designing a "precast" member vs. true CIP?






RE: Site Cast "Precast" Beams and Planks
RE: Site Cast "Precast" Beams and Planks
Interesting project.
Professional and Structural Engineer (ME, NH, MA)
American Concrete Industries
www.americanconcrete.com
RE: Site Cast "Precast" Beams and Planks
Embed angles at the bearing locations to prevent spalling due to repetitive construction/deconstruction.
RE: Site Cast "Precast" Beams and Planks
RE: Site Cast "Precast" Beams and Planks
I spoke with my usual PC supplier and we discussed some of the lifting concerns. All should be good now. It is going to be a cool project if it gets off the ground!
RE: Site Cast "Precast" Beams and Planks
I would NOT locate the rebar equally on each face. In fact, I would go out of my way to design it so that the students would need to think and figure out which orientation would be best. There would need to be some identification on the beams, or perhaps tapered beams that would go along with some form of summary of how they are reinforced. Or mark the faces of a rectangular beam 1, 2 , 3, 4. Mark the upper and lower surfaces of the slabs A and B and reinforce them differently. Make it so that they could physically be installed in both the proper orientation and the improper orientation, put lifting lugs on all sides, then grade them on how they thought it through and assembled. Could be quite a fun design exercise to consider all the load cases to make sure all the correct orientations work structurally and the incorrect ones do not work structurally (while having adequate capacity not to collapse .... although unlikely if no live loads applied). Heck, throw in some variations, i.e. if they need 20 beams, have 30 made, make sure 10 of them have some mistakes, i.e. enough area of reinforcement, but bars spaced too close together ... the possibilities are endless.