Need a book? Engineering books recommendations...
Re: Masonry Expansion Joints[Subject Prev][Subject Next][Thread Prev][Thread Next]
- To: seaint(--nospam--at)seaint.org
- Subject: Re: Masonry Expansion Joints
- From: "Bill Sherman" <SHERMANWC(--nospam--at)cdm.com>
- Date: 09 Dec 98 15:12:54 -0500
If you are talking about "concrete masonry units", I generally provide "control joints" rather than "expansion joints". (The main problem with CMU is shrinkage, not expansion. But with clay brick, expansion is a concern.) I use a CMU lintel beam and extend it with 8-inches (min) bearing each end. If I'm using a control joint, I offset the control joint above the opening by the width of the lintel bearing length and provide an unbonded sliding surface for the lintel bearing on that side. I use a masonry control joint detail which permits lateral load transfer between units but doesn't prevent shrinkage. Regarding spacing of CMU control joints, I use a larger spacing if I am providing horizontal reinforcement and moisture-controlled units. With prefabricated joint reinforcement at 16-inches on center, NCMA (TEK Note 53) recommends a maximum panel length/height ratio of 3 with an upper limit of 50-ft (vs a ratio of 2 and a limit of 40-ft for unreinforced). A well-reinforced seismic wall with uniformly spaced bond beams should be even better. Any bond beam which must transmit structural loads (as opposed to being only for crack control or local stresses) should be continuous thru control joints (e.g., roof chords or bond beams carrying lateral loads).
- Prev by Subject: Re: Masonry Expansion Joints
- Next by Subject: Re: Masonry Expansion Joints
- Previous by thread: RE: Masonry Expansion Joints
- Next by thread: Re: Masonry Expansion Joints