Deletion legend:
[1- Default – Not related to structural wind resistance design]
[2- Fire/Life Safety]
[3- Covered in model base code]
[4- Code Cycle Modification to be submitted to strike section and
refer to appropriate FBC,B sections]
SECTION
4407
[4- Code Cycle Modification to be submitted to strike section and
refer to appropriate FBC,B sections]
HIGH-VELOCITY
HURRICANE ZONES — MASONRY
R4407.1 Masonry shall be designed by a method
admitting of rational analysis based on established principles of mechanics.
SECTION
R4407.2
HIGH-VELOCITY
HURRICANE ZONES — QUALITY, TESTS, AND APPROVALS
R4407.2.1
Quality. The quality
of materials assembled into masonry and the method and manner of their assembly
shall conform to the requirements of this section.
R4407.2.1.1
Workmanship. Masonry
construction shall be in conformance with the tolerances, quality and methods
of construction as set forth in standards referenced in this section; the
Portland Cement Association Concrete Masonry Handbook , ANSI A41.1, A41.2 and
AWS Structural Welding Code: Reinforcing Steel (D1.4).
R4407.2.1.2
Other materials. A
material of masonry, other than set forth herein, which is incombustible and
otherwise sufficiently embodies the characteristics and satisfies the
requirements of one of the materials herein may be approved by the building
official, subject to such tests as may be prescribed.
R4407.2.2
Tests.
R4407.2.2.1 The building official may require
materials to be subjected to tests to determine their quality whenever there is
reason to believe that a material is no longer up to the standards on which the
approval was based. The cost of such tests shall be borne by the person or
persons proposing to use or continue to use such material or product.
R4407.2.2.2 Materials shall be tested in
accordance with the standard specifications of the ASTM International (ASTM) as
such standard specifications are noted in this section.
R4407.2.3
Approvals.
R4407.2.3.1 Only such masonry units as bear the
approval of the building official and are manufactured or fabricated by plants
having a certificate of competency issued by the authority having jurisdiction,
shall be considered acceptable for the construction of buildings or other
structures.
R4407.2.3.2 Approval of masonry units and
manufacturing or fabricating plants shall be for periods not to exceed one year
and may be obtained upon application and the submission of certificates of
tests in accordance with the provisions of this section.
R4407.2.3.3
The provisions for
tests for approval of masonry units shall not be construed as in lieu of any
tests otherwise required under this section.
R4407.2.3.4 Failure of a manufacturer of masonry
units to obtain approval or to submit tests as required in this section, or
such additional tests as the building official may require, shall be cause for
rejection of such masonry units.
R4407.2.4
Brick.
R4407.2.4.1
General. Brick shall
include masonry units usually 21/4 inches (57 mm) thick, 33/4 inches (95 mm)
wide, and 8 inches (203 mm) long, and not less than 75 percent solid.
R4407.2.4.2
Tests. Tests shall be
conducted in accordance with Standard Methods of Testing Brick, ASTM C 67.
R4407.2.4.3
Quality.
R4407.2.4.3.1 Burned clay or shale brick shall
conform to either the standard Specification for Building Brick (Solid Masonry
Units made from Clay or Shale), ASTM C 62, the Standard Specification for
Facing Brick (Solid Masonry Units made from Clay or Shale), ASTM C 216 or the
Standard Specification for Hollow Brick (Hollow Masonry Units made from Clay or
Shale), ASTM C 652.
R4407.2.4.3.2 Sand-lime brick shall conform to the
Standard Specification for Concrete Building Brick, ASTM C 55.
R4407.2.4.3.3 Concrete brick shall conform to the
Standard Specification for Concrete Building Brick, ASTM C 55.
R4407.2.5
Stone. Stone for
masonry shall be hard and durable.
R4407.2.6
Cast stone. Cast
stone shall be made of Portland cement, aggregates and water with or without admixtures.
Cast stone for load-bearing masonry or where exposed to the weather shall have
an average compressive strength, at 28 days, of at least 3,000 psi (20.7 MPa)
and shall have not more than 7 percent water absorption by weight.
R4407.2.7
Concrete blocks.
R4407.2.7.1
General.
R4407.2.7.1.1 Concrete blocks shall be made of
Portland cement, water and approved aggregates. The materials shall conform to
the requirements for the materials of concrete specified in Section R4405, and
the finished units shall meet the requirements of this section.
R4407.2.7.1.2 Concrete blocks used for
fire-resistive walls rated 2 hours or more, or used for load-bearing or
exterior walls, shall have a minimum face shell thickness of 11/4 inches (32
mm), a minimum web thickness of 1 inch (25 mm), and shall have a net
cross-sectional area not less than 50 percent of the gross section.
R4407.2.7.1.3 Concrete blocks for other purposes
shall have wall and web thickness of not less than 3/4 inch (19 mm).
R4407.2.7.1.4 Where masonry walls are required by
this code to be 8 inch (203 mm) thickness, hollow concrete blocks units may be
75/8 by 75/8 by 155/8 inches (195 by 195 by 398 mm) modular dimension with
corresponding widths for tie columns and tie beams.
R4407.2.7.2
Quality. Standard
units of hollow concrete block shall conform to the Standard Specification for
Hollow Load-Bearing Concrete Masonry Units, ASTM C 90, except that the maximum
moisture content shall not exceed 50 percent of the total absorption.
R4407.2.8
Structural clay tile.
R4407.2.8.1
Limitations. All
hollow burned clay wall tile used for fire-resistive walls rated 2 hours or
more, load-bearing or exterior walls shall be load-bearing tile.
R4407.2.8.2
Tests. Tests shall be
conducted in accordance with the Standard Methods of Sampling and Testing
Structural Clay Tile, ASTM C 212.
R4407.2.8.3
Quality.
R4407.2.8.3.1 Structural clay load-bearing wall
tile shall conform to the Standard Specification of Structural Clay
Load-Bearing Wall Tile, ASTM C 34.
R4407.2.8.3.2 Structural clay floor tile shall
conform to the Standard Specification for Structural Clay Floor Tile, ASTM C
57.
R4407.2.8.3.3 Structural clay nonload-bearing tile
shall conform to the Standard Specification for Structural Clay Nonload-Bearing
Tile, ASTM C 56.
R4407.2.9
Gypsum tile.
R4407.2.9.1
Limitations. Precast
gypsum shall not be used in load-bearing masonry or in any masonry that will be
exposed to the weather.
R4407.2.9.2
Tests. Tests shall be
made in accordance with the Chemical Analysis of Testing Gypsum and Gypsum
Products, ASTM C 471, Physical Testing of Gypsum Plasters and Gypsum Cement,
ASTM C 472, and Physical Testing of Gypsum Board Products and Gypsum Partition
Tile and Block, ASTM C 473.
R4407.2.9.3
Quality. Gypsum
partition tile or block shall conform to the Standard Specification for Gypsum
Tile or Block, ASTM C 52, Chemical Analysis of Testing Gypsum and Gypsum
Products, ASTM C 471, Physical Testing of Gypsum Plasters and Gypsum Cement,
ASTM C 472, and Physical Testing of Gypsum Board Products and Partition Tile
and Block, ASTM C 473.
R4407.2.10
Plain concrete. Plain
concrete is concrete cast in place and not reinforced, or reinforced only for
shrinkage or change of temperature. Plain concrete shall be mixed, placed and
cured as specified for concrete in Section R4405. The minimum strength of
regular concrete shall be not less than 2,000 psi (13.8 MPa) in 28 days. The
minimum strength of lightweight aggregate concrete shall be not less than 500
psi (3.5 MPa) in 28 days.
R4407.2.11 Plain gypsum concrete. Plain gypsum
concrete is gypsum concrete cast in place and either unreinforced or reinforced
for shrinkage.
R4407.2.12
Mortar.
R4407.2.12.1
General. Except as
otherwise set forth herein, all mortars and the materials therein shall conform
to the Standard Specifications for Mortar of Masonry Units, ASTM C 270.
R4407.2.12.1.1 The gradation of aggregates for
masonry mortar shall be such that the fineness modulus is between 1.20 and 2.35
when determined in accordance with the Standard Specifications for Aggregate
for Masonry Mortar, ASTM C 144.
R4407.2.12.1.2 Aggregates shall be quarried or
washed in fresh water and shall contain not more than 1/20 of 1 percent salt by
weight.
MORTAR
STRENGTH PROPERTY SPECIFICATIONS
Type
Minimum Average Strength
(psi) (MPa)
M 2500 (17.2)
S 1800 (12.4)
N 750 (5.2)
O 350 (2.4)
R4407.2.12.1.3 Mortar used to bond unit masonry
shall be of Type M, S, N or O and shall comply with either the property
specifications set forth hereinafter or the proportion specifications of the
standard set forth in R4407.2.12.1.
R4407.2.12.1.4 The type of mortar based on
consideration of the location of the unit masonry shall be as follows:
USE
OF LOCATION TYPE OF MORTAR
Below grade foundations
and walls M
Swimming pool walls and
retaining walls M
Fire resistive walls
rated 2 hours or more M or S
Exterior walls and load
bearing walls M or S
Piers less than 32
inches wide M or S
Partitions M, S or N
Solid masonry units One classification less than that above
Mortar or grout under
concentrated loads M
Fences M, S, N or O
Gypsum Gypsum
For SI: 1 inch = 25.4
mm.
R4407.2.12.1.5 All solid unit masonry shall be laid
in full beds with full end joints. All hollow unit masonry shall be laid with
full mortar coverage of the face shells in both horizontal and vertical joints.
SECTION
R4407.3
HIGH-VELOCITY
HURRICANE ZONES —
ALLOWABLE
UNIT STRESSES IN UNIT MASONRY
R4407.3.1
Compression.
R4407.3.1.1 Allowable working compressive
stresses in masonry walls shall not exceed the limits in pounds per square inch
(MPa) of gross area in the following table:
UNIT
TYPE N OR O MORTAR TYPE M OR S MORTAR
Brick 200 (1.4) 300
(2.1)
Stone 450 (3.1) 600
(4.1)
Rubble Stone 200 (1.4) 300
(2.1)
Concrete Blocks 100 (0.7) 150 (1.0)
Clay Tile 80 (0.55) 100 (0.7)
R4407.3.1.2 The maximum allowable working stress
in plain concrete shall be the following percentage of the ultimate strength of
the concrete in compression:
Compression 0.20 f ' c
Shear and diagonal
tension 0.02 f ' c
Where f ' c represents
the ultimate compressive strength.
R4407.3.2 The shear in unit masonry shall not
exceed 1/10 the allowable compressive stress.
R4407.3.3 Un-reinforced unit masonry shall be
assumed to have no value in resisting axial tension (uplift). Flexural tension
is allowed in unreinforced masonry per ACI 530.
R4407.3.4
Concentrations. Walls
of hollow masonry units shall not directly support concentrated loads.
SECTION
R4407.4
HIGH-VELOCITY
HURRICANE ZONES —
CONSTRUCTION
DETAILS
R4407.4.1
General.
R4407.4.1.1 Masonry walls of hollow or solid
units or plain concrete shall be constructed as specified in this section.
R4407.4.1.2 Designed reinforced concrete walls,
columns and beams shall be as specified in Section R4405, except that such
designed columns and beams shall be not less than the equivalent of the
minimums herein set forth.
R4407.4.1.3 Reinforced concrete required in this
section shall comply with Section R4405, Reinforced concrete.
R4407.4.1.4 Second-hand masonry units shall not be used
unless they conform to the requirements of this code, are sound and have been
thoroughly cleaned and are approved for use by the building official.
R4407.4.1.5 Bond shall be provided by lapping ends in
successive vertical courses.
R4407.4.1.6 Minimum No. 9 gauge horizontal joint
reinforcing at every alternate course (16 inches spacing), ladder type for
reinforced masonry and truss type for all others shall be provided. This
reinforcement shall extend 4 inches (102 mm) into tie columns or be tied to
structural columns with approved methods where structural columns replace the
tie columns.
R4407.4.2
Exterior walls.
R4407.4.2.1
General.
R4407.4.2.1.1 Exterior walls of unit masonry shall
have a minimum thickness of 8 inches (203 mm) except as otherwise set forth in
Sections R4407.2.7.1.4 and R4407.4.2.11
R4407.4.2.1.2 No roof or other members shall be
placed to develop direct horizontal thrust on walls unless such walls are
specifically designed.
R4407.4.2.1.3 The maximum area of wall panels of 8
inch (203 mm) thick unit masonry, as measured between the concrete members
which frame the panel such as the beams and tie columns, shall not exceed 240
square feet (22.3 m2), except as set forth in Section R4407.4.2.2.
R4407.4.2.2
Tie columns.
R4407.4.2.2.1 Concrete tie columns shall be
required in exterior walls of unit masonry. Concrete tie columns shall be
required at all corners, at intervals not to exceed 16 feet (4.9 m)
center-to-center of columns, adjacent to any corner opening exceeding 4 feet
(1219 mm) in width, and at the ends of free-standing walls exceed 2 feet (610
mm) in length. When openings exceed 8 feet (2.4 m) in width, tie columns shall
be provided on each side of all such openings. All gable and shed end corners
shall have tie columns.
R4407.4.2.2.2 When openings are between 3 feet and
8 feet (914 mm and 2438 mm) in width, such openings shall have one #5 vertical
reinforcing bar at each side. The vertical bars shall be placed in concrete
filled cells and shall extend into footings and into tie beams. All such bars
shall be continuous from footing to tie beam. All splices, where needed, shall
be 30 inches (762 mm) minimum.
R4407.4.2.2.3 Tie columns shall be not less than 12
inches (305 mm) in width. Tie columns having an unbraced height not exceeding
15 feet (4.6 m) shall be not less in thickness than the wall or less than a
nominal 8 inches (203 mm), and, where exceeding 15 feet (4.6 m) in unbraced
height, shall be not less in thickness than 12 inches (305 mm). The unbraced
height shall be taken at the point of positive lateral support in the direction
of consideration or the column may be designed to resist applicable lateral
loads based on rational analysis.
R4407.4.2.2.4 Tie columns shall be reinforced with
not less than four #5 vertical bars for 8 by 12 inch (203 by 305 mm) columns
nor less than four #6 vertical bars for 12 by 12 inch (305 by 305 mm) columns
nor less reinforcing steel than 0.01 of the cross-sectional area for columns of
other dimension nor less than may be required to resist axial loads or bending
forces. Vertical reinforcing shall be doweled to the footing and splices shall
be lapped 30 bar diameters. Columns shall be tied with #2 hoops spaced not more
than 12 inches (305 mm) apart.
R4407.4.2.2.5 The concrete tie columns set forth
herein are a minimum to limit masonry panel areas and provide an integrated
framework for masonry. The spacing of concrete columns for skeleton frame
construction, designed as specified in Section R4405, may exceed the spacing
herein set forth provided the masonry panels have an area less than 240 square
feet (22.3 m2) and the structural system is designed to transmit horizontal
wind loads to the columns.
R4407.4.2.2.6 Concrete tie columns designed to
limit masonry panel areas may be offset at tie beams or other horizontal
members to avoid openings, but the maximum spacing shall not be exceeded.
R4407.4.2.2.7 Concrete columns in load-bearing
walls shall be poured only after masonry units are in place. Where masonry
walls of skeleton frame construction are laid up after the frame has been
erected, adequate anchorage designed by a professional engineer shall be
provided. Where structural steel members are made fire-resistive with masonry
units, the panel walls shall be bonded to the fire-resistive materials.
R4407.4.2.2.8 Where the minimum spacing of tie
columns, as set forth in Section R4407.4.2.2.1, has been satisfied and where
structural columns of skeleton frame construction are spaced as specified in
Section R4407.4.2.2.5, provision for resisting the horizontal and vertical
loads at the edges of masonry panels abutting door and window openings in
masonry walls where openings are not bounded by such reinforced concrete
columns shall be considered and, where necessary, transfer the forces through the
materials of assembly to the ground.
R4407.4.2.3
Tie beams.
R4407.4.2.3.1 A tie beam of reinforced concrete
shall be placed in all walls of unit masonry, at each floor or roof level, and
at such intermediate levels as may be required to limit the vertical heights of
the masonry units to 16 feet (4.9 m). Well compacted and confined soil below
grade may be considered lateral restraint but only above a point 1 foot (305
mm) below the grade where such restraint begins.
R4407.4.2.3.2 Unless otherwise required by design,
all tie beams shall have four #3 ties at 12 inches (305 mm) o.c. at corners and
at each bend and at 48 inches (1219 mm) o.c. elsewhere. A tie beam shall be not
less in dimension or reinforcing than required for the conditions of loading nor
less than the following minimums: A tie beam shall have a width of not less
than a nominal 8 inches (203 mm), shall have a height of not less than 12
inches (305 mm) and shall be reinforced with not less than four #5 reinforcing
bars placed two at the top and two at the bottom of the beam except that a tie
beam using "U" type beam block may be used with the following
limitations:
1. Limited to one-story Group R3
occupancy.
2. Limited to unsupported spans of 7 feet
(2.1 m).
3. Beam block shall be reinforced with one
#7 bar in the top and one #7 bar in the bottom of the pour.
4. Beam block shall provide not less than
14 inches (356 mm) vertical dimension or less than 41/2 inches (114 mm)
horizontal dimension of poured-in-place beam cross-section.
5. Where beam blocks are used,
consideration of resistance to uplift caused by wind forces shall be based on
only that portion of the dead load above the topmost mortar joint in the wall.
R4407.4.2.3.3 The tie beam shall be continuous.
Continuity of the reinforcing in straight runs shall be provided by lapping
splices not less than 30 inches (762 mm). Continuity shall be provided at
corners by bending two bars from each direction around the corner 30 inches
(762 mm) or by adding two #5 bent bars which extend 30 inches (762 mm) each way
from the corner. Continuity at columns shall be provided by continuing
horizontal reinforcing through columns or by bending horizontal reinforcing in
the columns a distance of 18 inches (457 mm).
R4407.4.2.3.4 A tie beam shall not be required
where floor or roof systems provide a rigid diaphragm of reinforced concrete
with a minimum thickness of 4 inches (102 mm) or where a floor or roof system
has an equivalent stiffness factor of not less than 0.5 cubic inches, as
determined by the moment of inertia divided by the length. (Per foot of width,
measured normal to the plane of the diaphragm and adequately anchored).
R4407.4.2.3.5 Changes in level of the beams or
structural concrete beams (beam) shall be made at tie columns or structural
concrete columns and said tie columns or structural concrete columns shall be
continuous from beam to beam.
R4407.4.2.3.6 A tie beam may follow the rake of a
gable or shed end if the slope does not exceed 3:12 and the requirements of
Sections R4407.4.2.1.2 and R4407.4.2.1.3 are met.
R4407.4.2.3.7 The concrete in tie beams shall be
placed to bond to the masonry units immediately below and shall not be
separated therefrom by wood, felt or any other material which may prevent bond.
Felt paper no wider than the width of the cells of the block may be used
provided that it is depressed a minimum of 2 inches (51 mm) in one cell of each
block.
R4407.4.2.3.8 Tie beams subject to uplift and
lateral wind forces shall be sized and designed to resist all such forces. Tie
beams over openings shall be sized and designed to resist dead and live loads
combined with wind loads, whichever governs.
R4407.4.2.4 Gable end and shed end walls. All
masonry structures with gable end and shed end (half gable) walls shall have
such end walls constructed of masonry, only in accordance with this section. A
horizontal tie beam shall be provided in line with the lower ends of the gables
and sheds, except as permitted in Section R4407.4.2.3.6 above, and designed in
accordance with Sections R4407.4.2.1.2 and R4407.4.2.1.3, and load requirements
as set forth in Section R4403. A concrete coping following the rake of the
gable, not less than 64 square inches (413 cm2) in area reinforced with two #5
bars shall be provided. Tie columns at gable and shed ends shall be provided.
Any intermediate tie columns required within the gable shall extend to the
coping beam. Tie beams resting on masonry which are not subject to uplift and
lateral wind forces shall be provided according to Section R4407.4.2.3.2.
R4407.4.2.5
Parapet walls.
R4407.4.2.5.1 Masonry parapet walls shall be not
less than 8 inches (203 mm) thick, shall be reinforced with minimum tie columns
and shall be coped with a concrete beam not less than 64 square inches (413
cm2) in cross-section, reinforced with two #4 reinforcing bars.
R4407.4.2.5.2 A parapet wall exceeding 5 feet (1524
mm) in height above a tie beam or other point of lateral support shall be
specifically designed to resist horizontal wind loads.
R4407.4.2.6
Piers.
R4407.4.2.6.1 In any section of a masonry wall of
an enclosed structure where openings are arranged to leave sections of walls
less than 16 inches (406 mm), such sections shall be steel or reinforced
concrete.
R4407.4.2.6.2 Isolated masonry piers of unenclosed
structures shall be so constructed that the height of such piers shall not
exceed 10 times the least dimension, that the cells are filled with cement
grout and reinforced with not less than two #5 bars anchoring the beam to the
foundation.
R4407.4.2.7
Cavity walls.
R4407.4.2.7.1 Cavity walls consisting of two
separate walls with an air space of not less than 2 nor more than 6 inches (51
to 152 mm) may be constructed of solid or hollow-unit masonry provided such
walls meet the specific requirements for tie columns and beams set forth in
this section and are bonded together at intervals not more than 24 inches (610
mm) apart, vertically and horizontally, by masonry ties or by durable, rigid
metal ties 0.10 square inch (64.5 mm2) in cross-section.
R4407.4.2.7.2 The minimum thickness of the separate
walls of cavity wall construction shall be 4 inches (102 mm), and units shall
be laid in full beds of Portland cement mortar with full-end joints.
R4407.4.2.8
Brick and stone walls.
Walls of brick and stone shall be laterally supported by tie columns and beams,
or the equivalent thereof, as provided in this section and shall meet these
additional requirements:
1. In all brick walls at least every sixth
course on both sides of the wall shall be a header course or there shall be at
least one full header in every 72 square inches (465 cm2) of each wall surface.
2. In walls more than 12 inches (305 mm)
thick, the inner joints of header courses shall be covered with another header
course that shall break joints with the course below.
3. Solid-unit masonry shall comply with
the standard Building Code Requirements for Masonry, ANSI A41.1.
4. Rubble stone walls shall be 4 inches
(102 mm) thicker than is required for solid brick or concrete walls of the same
respective heights, but in no part less than 16 inches (406 mm).
R4407.4.2.9
Substitutions.
R4407.4.2.9.1 Where, for architectural reasons or
otherwise, it is desirable to reduce the area of any required tie column or tie
beam below the specified requirements, the building official may grant such
reduction, provided that the area of concrete omitted shall be replaced by
reinforcing or structural steel in the ratio 1:(n-1) where "n" is
defined as the Modular Ratio of Elasticity (Esteel/Econcrete).
R4407.4.2.9.2 Where it is desired to substitute for
the #5 reinforcing as required by this section, three #4 bars may be
substituted to replace two #5 bars.
R4407.4.2.10
Wall additions. Where
new walls are connected to existing walls, such connection shall be by means of
a starter column of minimum 8 by 8 inches (203 by 203 mm) dimension reinforced
with two #5 bars.
R4407.4.2.11
Chases, recesses and openings.
R4407.4.2.11.1 Unit masonry walls required to be a
minimum of 8 inches (203 mm) thick, such as exterior walls, fire walls and
bearing walls, may be chased or recessed not deeper than one-half the wall
thickness for an area not exceeding 8 square feet (0.74 m2), provided the
horizontal dimension of the chase or recess does not exceed 4 feet (1219 mm)
and provided the chasing shall not reduce the dimension of tie beams and tie
columns to less than herein required, except as follows:
Exception: Four-inch (102 mm) deep chases or
recesses in 8 inch (703 mm) unit masonry walls may be constructed with 4-inch
(102 mm) unit masonry panels provided such - inch (102 mm) unit masonry panel
does not exceed 5 feet (1524 mm) in width, does not exceed 8 feet (2.4 m) in
height, is bonded on one vertical side to 8 inch (203 mm) masonry or a tie
column, and is not load bearing. Where such panel exceeds 2 feet (610 mm) in
width at locations 20 feet (6.1 m) or more above grade in exterior walls,
resistance to wind load shall be considered in the design, and a minimum of
4-inch by 8-inch (102 mm by 203 mm) tie column with two #5 vertical bars shall
be provided in the free standing end of such 4-inch (102 mm) wall.
R4407.4.2.11.2 Openings shall have lintels of
reinforced concrete. Where such lintel is precast or formed separately from a
tie beam, it shall bear not less than nominal 8 inches (203 mm) on the masonry,
at each end except as may otherwise be approved for compliance with this code
by Product Approval, or after rational analysis, but not less than 4 inches
(102 mm). Where such lintel is formed integrally with the tie beam by deepening
the tie beam above the opening, and the tie beam itself is capable of safely
supporting all loads, the beam may span up to 6 feet (1.8 m) in length and may
be deepened not to exceed 8 inches (203 mm) without additional reinforcing.
Where the tie beam is deepened in excess of 8 inches (203 mm) with a span less
than 6 feet (1.8 m) in length, and the tie beam itself is capable of supporting
all loads, the dropped portion shall contain a #3 horizontal bar at the bottom,
bent up at each end and fastened to the upper tie beam steel or two #4
horizontal bars. The dropped portion shall bear at least 4 inches (102 mm) on
the masonry at each end. Where the span is in excess of 6 feet (1.8 m), the
principal beam reinforcing shall be at the bottom of the beam.
R4407.4.2.12
Glass block.
R4407.4.2.12.1 Masonry of glass unit masonry may be
used in nonload-bearing exterior or interior walls and in openings which might otherwise
be filled with windows, either isolated or in continuous bands, provided the
glass unit masonry panels have a thickness of not less than 31/2 inches (89 mm)
at the mortar joint and the mortared surfaces of the units are satisfactorily
treated for mortar bonding.
R4407.4.2.12.2 Glass unit masonry panels for
exterior walls shall have a Product Approval.
R4407.4.2.12.3 Exterior unit masonry panels shall be
set in recesses at the jambs and, for panels exceeding 10 feet (3 m) in
horizontal dimension between supports, at the head as well, to provide a
bearing surface at least 1 inch (25 mm) wide along the panel edges; except that
when approved by the building official for panels exceeding neither 100 square
feet (9.3.m2) in area nor 10 feet (3 m) in either horizontal or vertical
dimension, and situated four stories or less, and less than 52 feet (15.8 m)
above grade level, anchorage may be provided by means of non - corrodible
perforated metal strips.
R4407.4.2.12.4 Glass unit masonry panels shall have
reinforcement in the mortar joints spaced not more than 2 feet (610 mm) apart
vertically and below and above any openings within a pane. The reinforcement
shall consist of two parallel longitudinal galvanized steel wires, No. 9 gauge
or larger, spaced 2 inches (51 mm) apart, and welded to No. 14 or heavier cross
wires at intervals not exceeding 8 inches (203 mm), or the equivalent approved
by the building official.
R4407.4.2.12.5 Glass unit masonry shall be laid in
only Type M or S mortar or equivalent approved material. Both vertical and
horizontal mortar joints shall be at least 1/4 inch (6 mm) and not more than
3/8 inch (9.5 mm) thick and shall be completely filled.
R4407.4.2.12.6 Every exterior glass unit masonry
panel shall be provided with expansion joints at the sides and top. Expansion
joints shall be entirely free of mortar, and shall be filled with resilient
material.
R4407.4.2.12.7 Glass masonry units required to
provide a fire resistance rating shall comply with Section R4407.4.1.12.8 or
shall be fire tested and listed for their intended use.
R4407.4.2.12.8 View panels in 1-hour fire-resistant
walls shall be limited to glass unit masonry panels installed in steel
channels, or panel anchor framing may be used where a 3/4-hour fire rating is
required. Three and seven-eighths inch (98 mm) thick glass masonry unit shall
be limited to 120 square feet (1.1 m2) with no dimension greater than 12 feet
(3.7 m) for masonry wall construction or to 94 square feet (8.7 m2) with no
dimension greater than 10.75 feet (3.3 m) for non-masonry
wall construction. Three and one-eighths inch (79 mm) thick glass masonry units
shall be limited to 100 square feet (9.3 m2) with no dimension greater than 10
feet (3 m) for masonry wall construction or to 94 square feet (8.7 m2) with no
dimension greater than 10.75 feet (3.3 m) for non-masonry
wall construction. Three inches (76 mm) thick glass masonry units shall be
limited to 100 square feet (9.3 m2) with no dimension greater than 12 feet (3.7
m) for masonry wall construction or to 94 square feet (8.7 m2) with no
dimension greater than 10 feet (3 m) for non-masonry
wall construction.
View panels in 2-hour fire resistant walls
shall be limited to glass masonry units installed in steel channels and with a
water curtain in conformance with NFPA 13 on each side at interior walls or at
the interior of exterior walls. Three and seven-eighths inch (98 mm) thick
glass masonry units shall be limited to 100 square feet (9.3 m2) with no
dimension greater than 10 feet (3 m).
The view panel assembly
shall not exceed 25 percent of the wall separating a tenancy from a corridor or
a corridor from an enclosed vertical opening or one fire-rated area from
another fire-rated area.
Maximum 3/4-hour
fire-rated glass masonry units construction shall be used at non-masonry wall construction. Panel anchors
shall be provided at sill and jambs in non-masonry wall
construction using panel anchor framing. A fire retardant sealant shall be used
at all channel and panel anchor framing. Expansion material at heads and jambs
shall be either fibrous glass or mineral wool. All fire rated glass masonry
units and panels shall conform to UL No. 9 and ASTM E 163.
R4407.4.2.12.9 Interior glass masonry unit panels
having thickness of 37/8 inches (98 mm) shall not exceed 250 square feet (23.2
m2) of unsupported wall surface and interior glass masonry unit panels having
thickness of 31/8 inches (79 mm) shall not exceed 150 square feet (13.9 m2) of
unsupported wall surface nor more than 25 feet (7.6 m) in length nor more than
20 feet (6.1 m) in height between supports.
R4407.4.2.13
Grill block.
R4407.4.2.13.1 Decorative grills or screens
constructed of unit masonry laid with cells open through the wall shall be as
set forth herein or designs shall be based on rational analysis to resist
applicable loads and computations shall be submitted to the building official
for approval.
R4407.4.2.13.2 Unit masonry grills or screens as
described in this paragraph shall not be load bearing.
R4407.4.2.13.3 Unit masonry in exterior wall shall
be laid in Type M or S mortar.
R4407.4.3
Interior bearing walls.
Interior-bearing walls shall be constructed as specified in Section R4407.4.2
for exterior walls, except that interior bearing walls in one-story building of
Group H or I occupancy, where not required to be more than 1-hour
fire-resistive, may be constructed of 4 inch (162 mm) concrete block not
exceeding 9 feet (2.7 m) in height, capped with a reinforced concrete beam not
less than 4 inches (102 mm) in width nor less than 12 inches (305 mm) in
height, reinforced with two 1/2-inch rods (12.7 mm), and such walls shall
support only a roof or ceiling not in excess of 700 pounds per lineal foot
(10.2 kN/m) with no chases or recesses.
R4407.4.4 Fire walls.
Firewalls shall be constructed as set forth in Section R4407.4.2 for exterior
walls.
[2- Fire/Life Safety]
R4407.4.5
Panel walls.
R4407.4.5.1 Panel walls of unit-masonry shall be
not less than 8 inches (203 mm) thick and shall be limited in panel dimension
as set forth in Section R4407.4.2.
R4407.4.5.2 Panel walls of reinforced concrete
shall be not less than 4 inches (102 mm) thick nor less than required by design
as specified in Section R4405.
R4407.4.6
Veneered walls.
R4407.4.6.1
Masonry backing.
R4407.4.6.1.1 Veneering or facing on masonry
backing shall not be considered as adding any strength to such walls and shall
be limited in height above foundations or between proper and adequate supports
to 30 feet (9.1 m). Veneering shall be securely anchored to masonry backing by
means of substantial, non-corroding
metal wall ties, spaced not farther apart than 16 inches (406 mm) vertically or
24 inches (610 mm) horizontally.
R4407.4.6.1.2 Tile veneering, not more than 1 inch
(25 mm) thick with individual units not exceeding 20 inches (508 mm) in any
dimension and having not more than 200 square inches (1290 cm2) of surface area
with corrugations or scoring on the back side thereof, need not be anchored in
accordance with the above requirements but shall be cemented solid to the
backing with Portland cement mortar so as to provide a continuous integral
support to the backing.
R4407.4.6.2
Wood backing.
R4407.4.6.2.1 In all cases, before applying masonry
veneer, a substantial waterproofed paper or asphalt-saturated felt, weighing
not less than 14 pounds per 100 square feet (0.68 kg/m2) shall be applied
horizontally, shingle fashion, over diagonal sheathing. Horizontal joints in
the paper or felt shall be lapped not less than 4 inches (102 mm) and vertical
end joints not less than 6 inches (152 mm).
R4407.4.6.2.2 Masonry veneer shall be not less than
33/4 inches (95 mm) thick and shall be bonded to the backing by means of
substantial non-corroding metal wall ties
spaced not farther apart than 16 inches (406 mm) vertically and 24 inches (610
mm) horizontally.
R4407.4.7 Partitions.
R4407.4.7.1 The
requirements specified herein shall apply to non-bearing interior separations,
other than firewalls, of unit masonry construction.
R4407.4.7.2 The
lateral distance between vertical supports of non-bearing interior partitions
of unit-masonry shall not exceed 72 times the actual thickness of the
partition, including plaster.
R4407.4.7.3 The
height of unit masonry partitions shall not exceed 36 times the actual
thickness, including plaster.
R4407.4.7.4 All
interior unit masonry partitions shall be designed to meet the lateral live
load requirements with corresponding perimeter anchorage supports, in
accordance with Section R4403.7.8.
[1- Default – Not
related to structural wind resistance design]
R4407.4.8
Fences.
R4407.4.8.1 Masonry fences so located on a
property that such fence, at the proposed height or by a future addition to
height, could be used as a wall of a building shall be constructed with
foundations and tie columns as provided for an exterior wall. Such fence shall
be capped with a coping beam not less than 64 square inches (413 cm2) in
cross-section reinforced with a minimum of two #4 rods, when not exceeding a
height of 5 feet (1.5 m), or shall be capped by a tie beam as provided for
exterior walls if exceeding a height of 5 feet (1.5 m).
R4407.4.8.2 Masonry fences, so located on a
property that by zoning regulation such fence could not be used as a wall of a
building, shall be constructed as follows:
R4407.4.8.2.1 Fences not exceeding 5 feet (1.5 m)
in height shall be 8 inches (203 mm) thick and shall not be required to have
tie columns, but shall be required to have a coping as provided herein; or such
fences may be 4 inches (102 mm) thick with tie columns and coping not less than
8 inches (203 mm) thick.
R4407.4.8.2.2 Fences exceeding 5 feet (1.5 m) in
height shall be not less than 8 inches (203 mm) thick and shall have tie
columns and tie beams as required for exterior walls.
R4407.4.9
Other masonry walls.
Walls of masonry materials or arrangements of masonry units other than those
specifically set forth in this section shall be in conformance with the general
provisions of this code, may be classified by the subject to all or any of the
requirements therefor to and any such additional requirements as the building
official may prescribe.
SECTION
R4407.5
HIGH-VELOCITY
HURRICANE ZONES — REINFORCED UNIT MASONRY
R4407.5.1
Standards. The provisions of TMS 402/ACI 530/ASCE 5, and TMS 602/ACI
530.1/ASCE6 are hereby adopted as a minimum for the design and construction of
reinforced unit masonry. In addition to TMS 402/ ACI 530/ ASCE 5 and TMS
602/ACI 530.1/ASCE6 reinforced unit masonry structures shall comply with
Sections R4407.2
Exception:
Unless otherwise specified by the
designing architect or engineer, where plan review and inspections are
performed by a local building department in accordance with Sections 106 and
109, the provisions of TMS 402/ ACI 530/ASCE 5/TMS 402, Chapter 1, Section 1.18
and TMS 602/ ACI 530.1/ASCE 6/ Sections 1.5 and 1.6 shall not apply.
R4407.5.2
General. Reserved.
R4407.5.3 The design
of buildings and structures of reinforced unit masonry shall be by a
professional engineer or registered architect.
R4407.5.4 Special inspector. A Florida-registered architect or
professional engineer shall furnish inspection of all reinforced unit masonry
structures.
R4407.5.5
Concrete masonry strength. Concrete
masonry strength shall be determined by unit strength method from TMS 602/ACI
530.1/ ASCE 6 Section 1.4 or in accordance with ASTM C 1314.
R4407.5.6.
Reinforcement. Reinforcement shall
comply with TMS 402/ACI 530/ ASCE 5 and TMS 602/ ACI 530.1/ ASCE 6 except as
modified herein.
R4407.5.6.1
Development of bars in tension and compression shall be in accordance
with TMS 402/ASCE 530/ ASCE5 Section 2.1.9.3 with the following changes to the
factor y of Equation 2-12.
y = 1.0 for No. 3 (M#10) through No. 5 (M#16) bars;
y = 1.04 for No. 6 (M#19) through No. 7 (M#22)
bars; and
y = 1.2 for No. 8 (M#25) through No. 11 (M#36)
bars
Where epoxy coated bars are used, lap length
shall be increased by 50 percent.
R4407.5.6.2
Splices of reinforcement shall be in accordance with TMS 402/ ACI 530/
ASCE 5. Lap splices, welded splices, or mechanical splices are permitted in
accordance with the provisions of TMS 402/ ACI 530/ ASCE 5 Section 2.1.9.7.
Welding shall conform to AWS D1.4.
R4407.5.6.3
Lap splices shall be in accordance
with TMS 402/ ACI 530/ ASCE 5, Section 2.1.9.7.1.1 with the modifications of
Section 2122.4.1 to the factor y of Equation 2-12. In no case shall the length
of the lapped splice be less than 48 bar diameters, but not less than 12
inches.
R4407.5.6.4
Joint reinforcement. Horizontal
joint reinforcement shall be provided at every other course. Joint
reinforcement shall be a minimum of No. 9 gauge and shall comply with TMS
602/ACI 530.1/ ASCE 6 Sections 2.4C through 2.4F. Joint reinforcement shall be
placed in accordance with TMS 602/ACI 530.1/ ASCE 6 Section 3.4 B.7.
R4407.5.7
Concentrated loads shall be in
accordance with TMS 402/ ACI 530/ ASCE 5 Sections 1.9.7.2 and 2.1.8 and
shall not be assumed distributed across continuous vertical joints, including
stack bond joints, unless reinforcing elements are designed and provided to
distribute such loads.
R4407.5.8 Reinforced
masonry bearing walls shall have a nominal thickness of not less than 8 inches
(203 mm).
R4407.5.9
Anchorage requirements. Anchorage shall be in accordance with TMS 402/ ACI
530/ ASCE 5. Loading shall comply with TMS 402/ ACI 530/ ASCE 5 Section 1.7 and
the following.
R4407.5.9.1
Reinforced masonry walls shall be
securely anchored to adjacent structural members such as roofs, floors,
columns, pilasters, buttresses and intersection walls.
R4407.5.9.2
Masonry walls shall be anchored to
all floors and roofs that provide lateral support to such walls.
R4407.5.9.3
Such anchorage shall provide a
positive direct connection capable of resisting the horizontal forces as
required in Chapter 16 (High-Velocity Hurricane Zones), or a minimum force of
200 pounds per lineal foot (2919 N/m) of wall, whichever is greater.
R4407.5.9.4
Required anchors shall be embedded
in reinforced grouted cells. Anchor bolts shall be installed in accordance with
TMS 602/ ACI 530.1/ ASCE 6 Section 3.4 D
R4407.5.9.5
Wood framing connected by nails
shall not be considered as acceptable anchorage.
R4407.5.10 Mortar and grout.
R4407.5.10.1
Mortar materials shall comply with
TMS 602/ ACI 530.1/ ASCE 6 Section 2.1. Grout materials shall comply with TMS
602/ ACI 530.1/ ASCE 6 Section 2.2.
R4407.5.10.2
Vertical cells to be grouted shall
provided vertical alignment sufficient to maintain clear, unobstructed,
continuous, vertical cores measuring not less than 2 ½ inches by 3 inches (51
mm by 76 mm) for fine aggregate grout and 3 inches by 3 inches for coarse
aggregate grout as defined by ASTM C 476. The architect or engineer may specify
other grout space sizes shall be permitted provided they comply with TMS 402/
ACI 530/ ASCE 5 Section 1.19 and TMS 602/ ACI 530.1/ ASCE 6 Section 3.5C.
R4407.5.10.3
Placing of mortar and masonry units
shall comply with TMS 602/ ACI 530.1/ ASCE 6 Section 3.3.
R4407.5.10.4
Grout placement. Grout placement
shall be in accordance with TMS 402/ ACI 530/ ASCE 5 and TMS 602/ ACI 530.1/
ASCE 6.
R4407.5.10.5 Confinement. Confine grout to the areas
indicated on the Project Drawings. Use material to confine grout that permits
bond between masonry units and mortar.
R4407.5.10.6
Unless otherwise required, mix
grout other than self-consolidating grout to a consistency that has a slump
between 8 and 11 in. (203 and 279 mm). Self-consolidating grout shall comply
with TMS 602/ ACI 530.1/ ASCE 6
R4407.5.10.7
Grout shall be placed before any
initial set has occurred, but in no case more than 1-1/2 hours after the
mix-designed water has been added.
R4407.5.10.8 Grouting shall be a continuous operation in
lifts not exceeding 5 feet (1.5 m) and a maximum pour of 12 feet 8 inches (3.8
m). Grout placement shall comply with TMS 602/ ACI 530.1/ ASCE 6.
R4407.5.10.9
Grouting shall be consolidated
between lifts by puddling, rodding or mechanical vibration.
R4407.5.10.10. Grout keys shall be formed between grout pours. Grout keys shall be
formed between grout lifts when the first lift is permitted to set prior to
placement of the subsequent lift.
1. Form a grout key by terminating the grout a minimum of 1½ in. (38.1
mm) below a mortar joint.
2. Do not form grout keys within beams.
3. At beams or lintels laid with closed bottom units, terminate the grout
pour at the bottom of the beam or lintel without forming a grout key.
R4407.5.11
Bearing. Precast floor and roof
units supported on masonry walls shall provide minimum bearing of 3 inches (76
mm) and anchorage in accordance with Section R4407.5.9.4.
R4407.5.12 Intersecting walls shall comply with
TMS 402/ ACI 530/ ASCE 5 Section 1.9.4.