Need a book? Engineering books recommendations...

Return to index: [Subject] [Thread] [Date] [Author]

RE: Verification test

[Subject Prev][Subject Next][Thread Prev][Thread Next]
My observation has been that precasters have better forms in more controlled 
 environments, with better trained crews under better QC oversight.

The sticking isn't just suction.  I've seen tilt walls get stuck to their 
casting slabs and have to be dynamically yanked up by the crane, with help 
from big pry bars every few feet around the perimeter.  The wall still had 
chunks of broken concrete adhered to the face, torn from the casting slab. 
That's in Florida, where torrential rains can wash away form oil, and / or 
have inadequate coverage by the unsophisticated laborers who apply it.  To 
compound the problem, the casting slabs used cheap concrete, which was more 
 porous and had a less finely finished (more textured) surface than if they 
 were cast on a building slab.  (They saved money on that wall, until their 
 finishers showed up on site.)  It's always a challenge to design around 
that sort of thing.

(Picture attached, but I don't know whether it will get through.)


-----Original Message-----
From: seaint-seaosc(--nospam--at) [mailto:seaint-seaosc(--nospam--at)] On 
Behalf Of Matthew Stuart Sent: Thursday, September 03, 2015 12:59 PM
To: seaint-seaosc(--nospam--at)
Subject: RE: [SEAINT-SEAOSC] Verification test

I have always thought that the difference in the approach to analyzing tilt-up 
 vs. precast stripping stresses was interesting.  Of course most precasters 
 strip vertically and tilt-up is literally rotated into place.

Matthew Stuart, P.E., S.E., P.Eng., F.ASCE, F.SEI, SECB Structural Division 
 Manager Pennoni 3001 Market Street
Philadelphia, PA 19104
Direct: 215-254-7895 | Cell: 908-309-8657 mstuart(--nospam--at)

-----Original Message-----
From: seaint-seaosc(--nospam--at) [mailto:seaint-seaosc(--nospam--at)] On 
Behalf Of Jim Getaz Sent: Thursday, September 03, 2015 9:51 AM To: 
seaint-seaosc(--nospam--at) Subject: RE: [SEAINT-SEAOSC] Verification test

		As a plant-cast precaster, tilt-up is a dirty word, but we think that "bed 
 suction" is about the same as the weight of the panel. So a crane will exert 
 20,000# momentarily to free a 10,000# panel from the casting table. Therefore, 
 the crane operator tries to lift one edge first so he's only exerting 10,000# 
 to lift half of a 10,000# panel. Lots of texture on the form is assumed to

Truncated 646 characters in the previous message to save energy.

Post your message to the list by sending it to: 

The email messages sent to the list will be saved in an archive on the World Wide Web.
These archives are located at:

To contact the list owner, send your message to:

Sponsored By: Pacific Structural & Forensic Engineers Group, Inc. (PSFEG)

To unsubscribe, switch to/from digest, get on/off vacation, or change your email address, click here.