JOINT RESTRAINT
JOINT RESTRAINT
(OP)
What is the difference between restrained joints and mechanical joint retainer glands? Do both also require the use of concrete thrust blocks?
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RE: JOINT RESTRAINT
So a mechanical joint retainer gland assembly is a restrained joint and would not require a thrust block at the location of the assembly.
http://www.ebaa.com/Products/1200/
RE: JOINT RESTRAINT
RE: JOINT RESTRAINT
RE: JOINT RESTRAINT
RE: JOINT RESTRAINT
If MJ with restrained joints specified, there is no need for thrust blocks.
RE: JOINT RESTRAINT
Regular gland: need t-blocks
Retainer gland: use not recomended under any circumstance, it is a regular gland with set screws. The set screws produce a point load which will crack Cast iron, split c-900 and can crack poor quality ductile. The set screws can slip under higher loads such during a water hammer event.
Wedge action restrained joint system: (as described by wwtpguru) I use all the time. Get the restrained joint pipe length calculator from the manufacturers to calculate how far the restrained joints need to be for a safe installation, in most cases you will need to restrain more than one length of pipe.
Hydrae
RE: JOINT RESTRAINT
It is becomming more and more common to use mechanical joint restraints on pipe in lieu of concrete thrust blocks. I do not know if the work you speak of will be for private or municipal work. Some municipalities do not allow the use of mechanical restraints while some require both thrust blocks and restraints (overkill in my book). I have designed numerous domestic water and fire system lines in the Southern California region. If you intend to proceed with mechanical restraints, in lieu of thrust blocks, make sure the bell and spigots of the pipes also are restrained. There is a good restraint design program, available for free, from ebaa iron (probably the best manufacturer of these devices) at http://www.ebaa.com/engineering.htm
Both pvc c-900 and ductile iron pipe will need to have mechanical bell restraint harnesses installed in addition to those at bends & fittings.
RE: JOINT RESTRAINT