tranverse loading values for unreinforced CMU infill
tranverse loading values for unreinforced CMU infill
(OP)
While doing the demolition for a sidewalk replacement, the contractor uncovered an abandoned underground vault 6' deep, projecting four feet from the building. The 6' tall by 4' wide opening from the vault to the basement was blocked in with 6" CMU set in a running bond. City requires that the vault be filled with compacted fill. Assuming the horizontal diaphragm above is rigid the required controlled fill will have the at rest pressure of 60 PSF/ft-of-depth. The basement walls for the 75 year old building are CIP concrete with the opening supported by steel above so boundary stiffness is not an issue. Likewise all perimeter gaps of the CMU panel are mortared [and will be pinned to the CIP if needed.] Failure mode likely would be through an overstressed horizontal joint acting as a plastic hinge. Even after the cohesive failure of that mortar course, intuitively the panel would still have plenty of strength. [design lat loading just north of 1k/lf] However I am lost how to calculate ultimate failure values.






RE: tranverse loading values for unreinforced CMU infill
Usual Values of fd
Ladrillo macizo (Brick till 10% voids): 20 kgf/cm2
Ladrillo perforado (Brick over 10% voids): 16 kgf/cm2
Ladrillo Hueco (Brick with transverse voids): 10 kgf/cm2
Concrete Block: 14 to 20 kgf/cm2
Ceramic Block: 16 kgf/cm2
Adobe and Tapial: 1 to 3 kgf/cm2
Cut Hard Stones such Granite and Basalt: 40 to 80 kgf/cm2
Rough Hard Stones such Granite and Basalt: 7 to 25 kgf/cm2
Cut Limestone, Sandstone: 20 to 40 kgf/cm2
Rough Limestone, Sandstone: 6 to 12 kgf/cm2
Cut Soft Limestone or Sandstone: 10 to 20 kgf/cm2
Rough Soft Limestone or Sandstone: 5 to 8 kgf/cm2
1 kgf/cm2 = 14.223 psi
Most likely can be used directly for your check against a plate representation of the masonry under the earth pressure.
RE: tranverse loading values for unreinforced CMU infill
RE: tranverse loading values for unreinforced CMU infill
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RE: tranverse loading values for unreinforced CMU infill
So I was incorrect at proposing my first values as check against plate stresses if the plates made of the true thickness of the wall; it could be true for notional plates of included thickness and less than the wall thickness that follow a funicular or cuasifunicular surface of the standing pressures. For the flexural aspects etc use the other two references ... have more to look at so keep asking if not enough to cover what you want.
RE: tranverse loading values for unreinforced CMU infill
RE: tranverse loading values for unreinforced CMU infill
RE: tranverse loading values for unreinforced CMU infill
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BA
RE: tranverse loading values for unreinforced CMU infill
RE: tranverse loading values for unreinforced CMU infill
BA
RE: tranverse loading values for unreinforced CMU infill
Thanks for the helpful responses.
I did find a NIOSH study which conceptualizes transversely loaded dry-stack blocks as a three hinge arch and then empirically derives a formula through testing different blocks, thicknesses, and heights when stacked blocks are placed between two platens. the upper platen stays fixed
and the lower platen moves at a constant velocity [perpendicular to the wall] until crush zones are created on opposite edges of the block wall
http://1
With a boundry condition of infinite rigidity the authors Barczak-TM, Batchler-TJ (2008)strongly correlated the following:
transverse wall strength = f_cx * (t/L)^2 where
f_cx = unit block compressive strength
t = block thickness
L = wall height
just for general interest: the site is in NYC and special permits, controlled inspectors, and specially licensed contractors are pretty much required any time over 50 yds of concrete gets poured. that alone might make the owner opt against concrete fill.