Masonry Code Update From 11 To 13
Masonry Code Update From 11 To 13
Masonry Code Update From 11 To 13
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Changes in 2012 IBC for Masonry
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2011 TMS 402 Code
Chapter 1 Chapter 2: Allowable stress design
1.1 Scope
Chapter 3: Strength design
1.2 Contract documents SHHHHH, I wouldn’t
1.3 Approval of special systems Chapter 4: Prestressed masonry
1.4 Standards cited in this Code buy the 2011 version
Chapter 5: Empirical design
1.5 Notation if I were you….
1.6 Definitions Chapter 6: Veneer
1.7 Loading
1.8 Material properties
Chapter 7: Glass Unit Masonry
1.9 Section properties Chapter 8 AAC Masonry
1.10 Connection to structural frames
1.11 Masonry not laid in running bond Appendix B: Design of Masonry
1.12 Corbels Infills (NEW)
1.13 Beams
1.14 Columns
1.15 Pilasters
1.16 Details of reinforcement
1.17 Anchor bolts
1.18 Seismic design requirements
1.19 Quality assurance program
1.20 Construction
Reorganization: 2013 TMS 402 Code
Part 3: Part 4:
Part 5:
Part 2: Design Engineered Prescriptive
Part 1: General Design Design
Appendices &
Requirements References
Methods Methods
New Side-by-Side
format for the Code
& Commentary and
the Specification &
Commentary for
easier use by users
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New in the 2011 TMS 402
Updated to ASCE 7-10.
Required major recalibration as a
result of the change by ASCE 7 to
base wind loads on a “strength”
level versus a service level. As a
result, wind “triggers” changed for:
Empirical Design
Veneer
Glass Unit Masonry
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New in the 2011 TMS 402
Recalibration of Stresses
Removal of 1/3 stress increase option that was
formerly permitted for Allowable Stress Design
when considering wind or seismic loads (Don’t
worry there are other benefits coming later!)
Harmonization of ASD and SD shear provisions
Some Allowable Stresses increased.
Reduces impact of removal of 1/3 stress increase
Eliminated the conflict between the TMS 402 -
ASD loading provisions permitting the 1/3 stress
increase and the ASCE 7-05 prohibition of the
1/3 stress increase.
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2011 Allowable Stresses - General
Anchor Bolts: No change
A major Revision took place in 2008 which increased
Allowables; Harmonized with Strength Design
Bearing Stress
Increased from 0.25 f′m to 0.33 f′m
Nominal strength also increased from 0.60 f′m
to 0.80 f′m
Changes based on comparison with other codes
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2011 402 Allowable Stresses –
Unreinforced Masonry
Flexural Tension
Ft Increased by
33% based on
reliability
analysis
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2011 ASD Allowable Stresses –
Reinforced Masonry
Allowable Axial compression stress:
Unchanged
Allowable steel reinforcement stress:
Increased from 24 ksi to 32 ksi (Grade 60 steel) based on
comparison to strength design.
Allowable masonry stress - Combined Flexure & Axial loads:
Increased from 0.33f’m to 0.45f’m
Based on comparison to strength design
Shear strength provisions:
Now similar to strength design
Now permitted to ADD masonry and steel shear strength
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2011 ASD Allowable Stresses –
Reinforced Masonry
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2011 Allowable Stress Design
Reinforced Masonry - Shear
Shear strength provisions:
Now similar to strength design
Now permitted to ADD masonry and steel shear strength
Fv = Fvm + Fvs
Fvm
2
[
= (4.0 − 1.75(1.0)) f m′
1
] Fvm
1 M
= 4.0 − 1.75
2
f m′ + 0.25
Vd
P
An
For Typical Beam For Typical Wall
Av Fs d
Fvs = 0.5
An s
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2011 Special Shear Walls
1 M P
Fvm = 4.0 − 1.75 f m′ + 0.25
4 Vd An
Masonry allowable shear stress
decreased by a factor of 2, from ½
to ¼.
ASD: Design load required to be increased by
1.5 for shear
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Impact of 2011 Shear Provisions
8 in. Max.
Cover (K) for computation of
development length has been Lap Splice Length may be
8 in. Max.
Lap splices are permitted to
be reduced where transverse
reinforcement is placed
within 8” of the end of the
splice if it is fully developed in
grouted masonry.
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Development Length Comparison for
Change in K limit from 5db to 9db
Development Length (in)
Bar Size 2008 Code 2011 Code
8 in. CMU 12 in. CMU 8 in. CMU 12 in. CMU
3 15 15 12 12
4 20 20 14* 12
5 25 25 23* 14*
6 43* 39 43* 27*
7 59* 46 59* 37*
8 91* 60 91* 57*
9 118* 73* 118* 73*
f’m = 1500 psi, fy=60 ksi, bars centered in wall
* denotes K is controlled by masonry cover 21
New in the TMS 402 2011 – Possible
Splice Reduction with Transverse Steel
Placed within 8” of the end of the
splice and fully grouted
Not more than 1.5” horizontally from
vertical steel
Horizontal bar must be ‘fully
developed’ on each side of lap
Bent bar (shown)
Bond beam steel
Minimum lap required of 36 bar
diameters
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Possible Splice Reduction with
Transverse Steel
Example: 8” CMU, 1 vertical bar centered in cell, grade 60 steel
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Courtesy of the National Concrete Masonry Association
New in the 2011 TMS 402
Leff per 1.13.1
Deep Beam Provisions
added. Apply to beams where dv
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New in the 2011 TMS 402
Requirements for placement of non-contact lap
splices have been clarified
Splicing of bed-joint reinforcement clarification
Bending of foundation dowels have been clarified.
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New in the 2011 TMS 402
Anchor bolt
installation
requirements have
been revised.
Reference only to
running bond or “not
in running bond”
rather than reference
to stack bond or
other bond patterns.
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2012 IBC Special Inspection
Special Inspection
Tables for Masonry have
been deleted from IBC
Chapter 17, and it now
simply references the
2011 TMS 402 Quality
Assurance Tables
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New in the 2011 TMS 402
TMS 402 Quality Assurance tables were
expanded to include specific references to
applicable code and specification requirements.
(Similar references, which formerly were in the
IBC Special Inspection Tables, are not included
in the 2012 IBC, and thus were added here)
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2011 TMS 402 Grouting
Basic Requirements
Grout is placed in lifts not exceeding 5’-0” 5’-4”,
except;
24 ft.
5’-4”
High-lift grouting to build a 24-foot tall wall.
24 ft.
Cleanout
Method to high-lift grout a 24-foot tall wall
24 ft.
Cleanout
2011 Self-Consolidating Grout
Introduced self-consolidating grout (SCG).
Must have:
Minimum 2,000 psi compressive strength;
Slump flow of 24 to 30 inches; and
Visual Stability Index (VSI) less than or equal to 1
per ASTM C1611.
PARTITIONS
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CMU partition walls
2013 TMS 402-13 Chapter 14
CMU Partitions: ALWAYS may be designed using engineering
methods, or MAY be designed using prescriptive methods.
PROVIDED…..
Always in running bond for horizontally spanning walls
“Not laid in running bond” only to span vertically AND be solidly grouted.
Limits on building height, wind speeds and seismic loads exist.
Support vertical service load of 200 #/ft max in addition to own weight.
Resultant of vertical load in center 1/3 of wall thickness.
No axial tension
Max spans for service level unfactored lateral loads given for 5 psf and 10 psf
NOT ALLOWED in SDC D, E, or F.
Walls designed by prescriptive methods shall be “non-participating elements”
or not tied hard to main structure in a way to impart load to partition.
Only in Enclosed buildings
NOT ALLOWED in Risk Category IV structures
CMU partition walls
2013 TMS 402-13 Chapter 14
CMU partition walls
2013 TMS 402-13 Chapter 14
8” PARTITION Walls (5 psf):
Span = 26x t/12 =26 x 8”/12 ; Span = 17.33’
8” PARTITION Walls (10 psf):
Span = 18x t/12 =18 x 8”/12 ; Span = 12.00’
12” PARTITION Walls (5 psf):
Span = 26x t/12 =1 x 12”/12 ; Span = 26’
12” PARTITION Walls (10 psf):
Span = 18x t/12 =18 x 12”/12 ; Span = 18.00’
Cantilever partition walls: h/t = 6 for solid CMU ; h/t = 4 for hollow CMU.
NOTE: These values need adjusting to account for Openings.
CMU partition walls
2013 TMS 402-13 Chapter 14
For partition walls to brace each other at intersections
ANCHORAGE must be by one of the following;
50% of units laid in an overlapping bonding pattern with at least 3”
of bearing on the unit below.
Walls anchored at the intersection on intervals of not more than 16”
with joint reinforcement or ¼” mesh galvanized cloth.
Other anchors with equivalent areas as above.
F’m
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CMU Unit Strength Table
2013 TMS 602 Table 2
Net area
Net area compressive strength of ASTM
compressive
C90 concrete masonry units, psi (MPa)
strength of
concrete masonry,
Type M or S Mortar Type N Mortar
psi
1,700 --- 1,900
1,900 1,900 2,350
2,000 2,000 2,650
2,250 2,600 3,400
2,500 3,250 4,350
2,750 3,900 ----
Statistical Development
Effect of f′m = 2000 psi vs. f′m = 1500 psi
Allowable Stress Design
Small effect when allowable tension stress controls
Significant effect when allowable masonry stress controls
Strength Design
Small effect on flexural strength
Significant effect on axial strength
Significant effect on maximum reinforcement requirements
Both ASD and SD
13% decrease in development and splice length
15% increase in masonry shear strength
Effectively changes γg to 0.87 for masonry shear strength
2013 Partially Grouted Shear Walls:
In-Plane Shear Strength
ASD
8.3.5.1.2
Fv = (Fvm + Fvs )γ g SD V = (V + V )γ
9.3.4.1.2 n nm ns g
0.90
Mean St Dev = 0.776
Fully grouted
1.16
1.16 0.17
(Davis et al, 2010)
Partially grouted 0.90 0.26
(Minaie et al, 2010)
2013 TMS 402 Bond Beams
Figure CC-2.2-2 and SC - 1
(1)
(4)
(3) (2)
(2)
(1)
(5)
M or S N M or S N
Mortar
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MORTAR
M
MORTAR Confusion
What is the minimum required compressive strength for masonry mortars? We
often get Low Mortar tests.
Simply put, there are NO minimum compressive strength requirements for field-
batched masonry mortar in any current ASTM or building code.
There are, however, minimum compressive strength requirements for mortars
prepared and tested in the laboratory (ASTM C270).
TWO Primary ASTM testing for Masonry Mortar:
ASTM C270 Standard Specification for Mortar for Unit Masonry
ASTM C780 Standard test Method for Preconstruction and Construction Evaluation of
Mortars for Plan and Reinforced Unit Masonry
ASTM C780: Section 5.2.6 states “………The measured value shall not, however, be
construed as being representative of the actual strength of the mortar in the masonry.
ASTM C270: Section 3.1 “Specification C 270 is NOT a specification to determine
mortar strengths through field testing. (ie, only applies to lab prepared mortar)
In practice, the compressive strength requirements for masonry mortar contained in
ASTM C270 are often misapplied to field-batched mortar.
2013 ASTM C90:
Normalized Web Area
ASTM C-90 reduced limits on web thickness of CMU units
and added normalized web area
Caution: http://www.fendtproduct
s.com/products/concrete
• Reduces equivalent net thickness, which reduces fire ratings -masonry-units/h-form-
block.html
Awn =
Awt
×144 =
(1.25in.)(4.63in.) ×144 = 6.5in.2 / ft 2 This is minimum
(Ln )(H n ) (16in.)(8in.) normalized web area;
most block will have
Awn - normalized web area at least twice this
Awt - minimum web area area.
Ln - nominal length of unit
Hn - nominal height of the unit
Example: Normalized Web Area
0.6 × 46lb
× 1 ft width (8 ft ) 1.25in. web thickness
V=
wl
=
ft
= 110lb / ft
b= = 0.938in / ft
1ft
2 2 16in.
12in
7.63in. 1.25in.
Q = (1.25in. face shell thickness)12 in − = 47.8in 3 / ft
ft 2 2
fv = =
(
VQ 110lb / ft 47.8in3 / ft )
= 18.2 psi
Ib 309in / ft (0.938in / ft )
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