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# RE: Distribution of concentrated loads on masonry walls

• To: seaint(--nospam--at)seaint.org
• Subject: RE: Distribution of concentrated loads on masonry walls
• From: Cliff Schwinger <clifford234(--nospam--at)comcast.net>
• Date: Sat, 28 Sep 2002 11:15:52 -0400

```Thanks for the answer to my question Scott.

For anyone else out there who may be interested, I called NCMA about the
validity of assuming a 2 vertical: 1 horizontal distribution pattern for
concentrated loads on multistory masonry walls (with no limit on
effective width of the wall for running bond, no vertical joints, etc.)
and the engineer I spoke with basically confirmed that the b+4t
effective wall width limitation does not apply when you are looking at
multistory masonry bearing wall structures such as hotels, apartments,
etc.

To assume that concentrated loads on multi-story masonry bearing walls
do not continue to spread out beyond the b+4t limit would be grossly
conservative and unrealistic.

I will apply the b+4t limit to the panel of wall height (about 8 feet)
below where each concentrated load first occurs, but after the
concentrated load travels down one floor I will assume that the
unlimited spreading starts at the 2V:1H ratio). This is slightly more
conservative that what I used to do, but I figure that this is a way of
accounting for any unusual concentrated load effects on the first 8 feet
of block immediately below each concentrated load.

Cliff Schwinger

> -----Original Message-----
> From: Scott Maxwell [mailto:smaxwell(--nospam--at)engin.umich.edu]
> Sent: Thursday, September 26, 2002 9:25 PM
> To: seaint(--nospam--at)seaint.org
> Subject: Re: Distribution of concentrated loads on masonry walls
>
> Cliff,
>
> I don't recall any responses to your question, so I will take a stab.
>
> You raise a rather good point.  I have always thought that the
> concentrated load provision that you are referring to was for checking
the
> local bearing effects on the masonry and that the load would continue
to
> spread at a 45 degree angle for overall design of the wall (assuming
> running bond).  In otherwords, it seems to me that the provision that
you
> cite is for local failure-type design of the wall, not the "global"
> design.
>
> But, as you point out, it is not clear.  It certainly can be
interpreted
> that the provision is for the global design of the wall as well.  This
> appears to be another question to pose to the MSJC committee or
someone
> involved in the committee.
>
> I will see what I can come up with.
>
> HTH,
>
> Scott
> Ypsilanti, MI

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