From: Scott Maxwell <smaxwell(--nospam--at)engin.umich.edu>
Date: Mon, 24 Jan 2000 21:03:33 -0500
In addition, section 5.6.1 of the ACI 530-95 (also cross-reference as ASCE
5-95/TMS 402-95) Masonry Code or section 1.10.1 of the ACI 530-99 Masonry
code deals with "deflection of beam and lintels". This section states that:
Deflection of beams and lintels due to dead plus live loads shall not
exceed l/600 nor 0.3 in. (7.6 mm) when providing vertical support to
masonry elements designed in accordance with Chapter 6 or Chapter 9.
Note: This exact wording is taken from ACI 530-95. Chapter 6 is design of
unreinforced masonry using the "engineered" approach and Chapter 9 is
If my memory serves me correctly, this criteria is to minimize/prevent
cracking in masonry walls that are not supported on grade (either slabs on
grade or foundation walls).
Hope this helps.
Scott E. Maxwell, PE
500 Griswold, Suite 500
Detroit, MI 48226
Phone: (313) 442-8253
Fax: (313) 442-8297
Work Email: smaxwell(--nospam--at)dt.smithgroup.com
Personal Email: smaxwell(--nospam--at)engin.umich.edu
At 08:34 PM 01/24/2000 -0500, you wrote:
>Also: This is very strict, especially the 0.3" in one case this would be
>L/1100. Would it make sense to use shear studs on the perimeter beams to
>increase stiffness??? I would likely use a lesser amount for lateral
>support reasons anyway. I don't use shear studs too often; would the
>increase in stiffness be considerable or marginal?
>thanks again, David Handy
>At 06:36 PM 1/24/00 -0600, you wrote:
>>The UBC says to use L/600 for total deflection. The BIA says the lessor of
>>L/600 or 0.3". I tend to agree with the BIA unless you can cut the masonry
>>into smaller panels with properly detailed joints that can accommodate more
>>movement. I would recommend that you read the BIA Technical Note 28B.
>>> -----Original Message-----
>>> From: David Handy [SMTP:dhandy(--nospam--at)trg.ca]
>>> Sent: Monday, January 24, 2000 6:15 PM
>>> To: seaint(--nospam--at)seaint.org
>>> Subject: brick veneer support deflection
>>> What values do you use for meeting deflection requirements when supporting
>>> brick veneer at every floor. For example I have a building that use cast
>>> lintel angle wedge inserts. There is a 3" concrete slab for the floors
>>> is composite with the joists (HAMBRO). At the perimeter I am planning on a
>>> steel beam with the slab thickened to 8" to provide enough concrete for
>>> anchors. This beam supports only a small strip of floor where parallel to
>>> the joists and supports a 10' trib of floor where perpendicular. The shelf
>>> angle at the edge of the slab supports about 12' of brick at each floor.
>>> I have typically used L/720 for the beams using the live load plus half of
>>> the weight of the brick wall as the means for evaluating the deflection. I
>>> know that many would use just the live load and maybe even a less strict
>>> L/???. What do you think?
>>> David Handy, P.Eng
>>> Ontario, Canada