Agree with mrengineer, 271827, and archeng59. That is typically how we design our foundation systems. It allows for easier forming (ie cheaper) and monolithic pour. If you don't want to lower the bottom of the pier cap, adjust your clear cover in either the cap or the grade beam to allow the...
I'm assuming you have a backspan of 20-40 feet for this cantilever. Assuming that, you should be able to design it just like a regular cantilever beam and have dowels from your masonry walls match the slab reinforcing.
Rapt,
Thanks for the explanation. I may have been a little unclear in my last question. The beams I was referring to don’t have slab tendons running parallel to them since they are in a portion of the garage that could be converted to retail in the future. We didn’t want to run into any...
PTSlab,
The architect REALLY doesn't want shear walls in this garage, therefore we're relying on Ordinary Moment Resisting Frames for a Lateral System, so the beams do have to be dropped parallel to the slab. Not for gravity load so much as for lateral.
Thanks for the recommendation on...
I agree with TFL. We've used the 6k @ 18" to design the vehicle barriers on several garages. I believe that when factored up it equals the AISC's 10k load.
Thanks for the responses. The approach of designing the beam PT considering an effective width of slab is what I was planning on doing, but limiting the P/A to the rectangular area of the beam, not the effective flanges.
Adapt seems to anchor at the CG of the tributary cross-section, not the...
I'm designing a two-story parking garage using post-tensioned beams and slabs. It will be ordinary moment frames with three nominally 62' spans in one direction and 7-9 spans of between 22' and 32' in the other direction. My one-way slabs range in thickness from 7" to 9" and run in the short...
camber
I recently had a similiar question regarding the design of a new PT garage. According to ADAPT Tech. Support, you should use the actual unbraced height of the column in your runs. I'm sure you noticed noticable difference in the moments going to the columns, and consequently the PT...
I agree with SacreBleu and AggieYank. You need a better understanding of the actual equipment that will be used.
I recently checked the capacity of an existing two-way slab (designed for 60 psf) for a commercial kitchen load of 150 psf. It was my understanding that the 150 psf accounted for...
My office makes use of ADAPT for our post-tensioned design, though we didn't have a lot of PT projects till lately.
ADAPT-PT can design slabs (one- and two-way) and beams and has a fairly comprehensive output that will allow you to use the results in other modeling/design programs. You can...
mrengineer,
We are using essentially the procedure you described, taking the PT moments from ADAPT and adding/subtracting them from the appropriate column to get the "design" moments for the columns. We are using RAM and STAAD for the modeling and designing the PT beams and slabs in ADAPT-PT...
Wrightguy,
I am encountering the same situation with a garage design in OKC. The top floor of the garage empties out at street level on three sides of my garage. Luckily the architect/contractor/building inspector have agreed to deliniate a "fire lane" for the fire trucks so that I don't...
I've only had about 9 months of experience since graduating with my MS but I'd have to say that my firm is about 50-50 in regards to hand calcs and software. We use both Risa and RAM products to model structural systems, but tend to design typicals sections, simple beams and frames, slabs...
waytsh,
Sure, the detail is a part of the "ADAPT - Details; Post-Tensioning Details & Notes" sold by ADAPT. Its a set of recommended details and notes. My firm purchased it and received the spiral bound set of details (about 120), a set of typical plans, and actual set of plans from a Bijan...
waytsh,
I've got a standard detail from ADAPT that deals with stem penetrations. It limits the hole size to H/4 (your penetration seems to exceed this recommendation) and shows 2-#6 above and below each hole and 3-#4 stirrups @3" o.c. each side of the hole. Spacing for multiple holes is...
DesignIntegrity,
From the PTI Desighn, Construction, and Maintenance of CIP Parking Structures:
"Sleeves in the Anchorage Zone: The area behind the anchorage devices (18 in. behind the achorage device at 45 degree angles on each side . . .) is a region of high stress. Sleeves, block outs...