All materials permitted by this chapter, including their appropriate
allowable design values and those existing configurations of materials
specified herein, may be utilized to meet the requirements of this
chapter.
(§ 1, Ord. 678, eff. July 12, 1991)
All existing materials utilized as part of the required force
resisting system shall be in sound condition or shall be removed and
replaced with new material.
(§ 1, Ord. 678, eff. July 12, 1991)
(a) General. All URM walls utilized to carry vertical loads
or seismic forces parallel and perpendicular to the wall plane shall
be tested as specified in this section. All masonry that does not
meet or exceed the minimums standards established by this chapter
shall be removed and replaced by new materials or, alternatively,
shall have its structural functions replaced by new materials and
anchored to supporting elements.
(b) Lay-up of multiple wythe URM walls. The facing and backing
shall be bonded so that not less than 10% of the exposed face area
is composed of solid headers extending not less than four inches into
the backing, the clear distance between adjacent full-length headers
shall not exceed 24 inches vertically or horizontally. Where the backing
consists of two or more wythes, the headers shall extend not less
than four inches into the most distant wythe or the backing wythes
shall be bonded together with separate headers whose area and spacing
conform to the foregoing. Wythes of walls not bonded as described
above shall be considered as veneer. The veneer wythe shall not be
included in the effective thickness used in calculating the height
to thickness and the shear capacity of the wall.
(c) Mortar.
(1) Tests. The quality of mortar in all unreinforced
brick and hollow clay tile masonry walls shall be determined by performing
in-place shear tests in accordance with Uniform Building Code Standard
24-7. Alternative methods of testing shall be approved by the Building
Official for other types of masonry wall construction.
(2) Location of tests. The shear tests shall be taken
at locations representative of the mortar conditions throughout the
entire building, taking into account variations in workmanship at
different building height levels, variations in weathering of the
exterior surfaces and variations in the conditions of the interior
surfaces due to deterioration caused by leaks and condensation of
water and/or by the deleterious effects of other substances contained
within the building. The exact test location shall be determined at
the building site by the engineer in responsible charge of the structural
design work. An accurate record of all such tests and their location
in the building shall be recorded and these results shall be submitted
to the Building Official for approval as part of the structural analysis.
(3) Number of tests. The minimum number of tests per
class shall be as follows:
(i) At each of both the first and top stories, not less than two per
wall or line of wall elements providing a common line of resistance
to lateral forces.
(ii)
At each of all other stories, not less than one per wall or
line of wall elements providing a common line of resistance to lateral
forces.
(iii)
In any case, not less than one per 1,500 square feet of all
surface nor less than a total of eight.
(4) Minimum quality mortar.
(i) Mortar shear test values, Vto, in psi shall be obtained for each
in-place shear test in accordance with the following equation:
(ii)
Individual URM walls with Vto consistently less than 30 psi
shall be entirely pointed prior to retesting.
(iii)
The mortar shear strength, Vt, shall be the value in psi that
is exceeded by 80% of all of the mortar shear test values, Vto.
(iv)
Unreinforced masonry with mortar shear strength, Vt, less than
30 psi shall be removed or pointed and retested.
(5) Collar joints. The collar joints shall be inspected
at the test locations during each in-place shear test and estimates
of the percentage of the surfaces of adjacent wythes which are covered
with mortar shall be reported along with the results of the in-place
shear tests.
(6) Pointing. All deteriorated mortar joints in URM
walls shall be pointed according to Uniform Building Code Standard
No. 24-9. Nothing shall prevent pointing with mortar of all the masonry
wall joints before the tests are made.
(§ 1, Ord. 678, eff. July 12, 1991)
Existing wall anchors utilized as all or part of the required
tension anchors shall be tested in pullout according to Uniform Building
Code Standard 24-8. The minimum number of anchors tested shall be
four per floor, with two tests at walls with joists framing into the
wall and two tests at walls with joists parallel to the wall, but
not less than 10% of the total number of existing tension anchors
at each level.
(§ 1, Ord. 678, eff. July 12, 1991)