Prism Testing

[akastud]

Hey all,

I am in a small town that tends to be backwords at times, and most of the structural engineering has been done by civils who have tried hard, but sometimes don't understand the building code as well as they should to practice structural engineering, but that is a different subject for a different post. My question is about prism testing. The city reveiwers have told my client that no one requires prism testing (or other method as listed in the UBC) except our firm. As I understand it (we are using the 1997 UBC in this city), if you design masonry to the full capacity (ie. do not divide the allowables by 2) then special structural inspection is required as well as prism testing. The city seems to think that since no one else requires prisms when special inspection is required there must be a loophole in the code somewhere. I contacted the local testing agency engineer, and he says that he doesn't know, he just does what is required by the EOR. The city says that I get to specify what tests are done as part of the special inspection, but it seems to me that prism testing or other method is required. Does anyone else know any loophole, or anywhere that it says that the EOR specifies exactly what tests are done as part of the inspection.

akastud

 

[JAE]

Prism testing is only one of three ways to verify quality in masonry construction.

The section 1701.5.7. - Structural Masonry - covers the requirements for special inspection of masonry. It references the taking of prisms, but doesn't REQUIRE prisms...it only says that the inspector needs to be there to observe the taking of prisms if they are made at all.

UBC 97, section 2107.1.2 says that you simply divide by two if you don't do special inspections.

Now read section 2105.3. This sets compliance with f'm.

There are three ways to do this.
1. Prism tests
2. Prism test record
3. Unit strength method

Each of these three have separate provisions for full stress and half stress designs. Normally, most engineers use unit stresses unless a higher than normal f'm is required. This doesn't require prisms, just testing of units and grout.