maximum span.

[MSFire]

Does anyone know where I could find out the maximum span of an unsupported 215mm masonry wall. The wall would be supported only at its ends and would be tied into other walls at those ends.

Imagine the floor the wall was on 'disappearing'.

Thanks

Matt.

 

[Lutfi]

In the US, this is a function of many factors such as:

1. Vertical gravity loads (deal and live)
2. Eccentricity of the gravity loads
3. Lateral loads (wind and seismic)
4. The wall end/boundary conditions (pin/pin, fixed/pin)
5. Building code requirements (local, national, and ACI, etc.)
6. Strength of masonry, type of bond, type and strength of mortar.

I do not think you will find a chart that says certain size masonry wall will span so much without due consideration to the bullets mentioned above.

 

[mhnds]

MSfire, don't you think it may create problems regarding earthquakes to have a masonry wall which is not supported by a beam at the bottom along its length? umitk2211

 

[MSFire]

Hi

The question arises when the composite floor the wall is normally sitting on sags due to a fire below heating the supporting beams. The performance of the wall at this point is being investigated.

I suspect the wall will arch, however is there any supporting documentation you are aware of for this case?

Thanks

MSFIRE

 

[emceditor]

Even unreinforced masonry can arch under right conditions. In old masonry buildings you frequently can see the masonry over window and door openings cracked starting at the jambs and stepping up at approximately 45 degrees meeting in the middle (forming a triangle). That happens when the lintel is not stiff enough. Frequently lintels are designed to support only the triangular portion of the masonry. Some engineers use the 45 degree others a 60 degree angle. The triangle usually is assumed to be placed above the lintel, which comes into play with masonry or concrete lintels. The assumption is that the lintel will support only loads that fall within this triangle. The masonry above the triangle arches over this, and by doing so develops a thrust. In order for masonry to be able to arch, this thrust will need to be resisted. See

http://www.bia.org/html/frmset_thnt.htm

for additional information.