Overview of Masonry Codes
W. Mark McGinley , Ph. D. PE
University of Louisville
(from TMS seminars and R. Bennett)
1
The Masonry Society – Who we are

TMS is a not-for-profit professional society, whose
mission is simply to advance the knowledge of
masonry

TMS is the lead sponsor of the Masonry Standards
Joint Committee, who is responsible for the “MSJC”
standards (TMS 402/TMS 602)

For more information, visit us at:
www.masonrysociety.org
Slide 2
Masonry Codes and Standards

Almost the entire US now uses the
IBC. We will focus on the 2015 IBC.

The IBC extensively references
“Consensus” Design and Material
Standards:




ASTM Standards for Materials
ASCE 7 for Loads
ACI 318 for Concrete
“MSJC” (TMS 402/602) for Masonry
3
IBC Masonry Requirements

Chapter 7 – Fire Ratings

Chapter 14 – Veneer

Chapter 17 – Quality Assurance


Chapter 18 – Foundation Walls (includes
prescriptive requirements based on TMS 402
Strength Design Procedures)
Chapter 21 – Masonry
4
IBC Masonry Requirements

In the past, some of the TMS 402/602 provisions
were duplicated in the IBC. Differences between the
TMS 402/602 and the IBC were hard to spot. Same
was true of ASTM Standards.

Most of these duplicate provisions were removed
from the 2009 IBC, making differences much easier
to spot. More duplicate provisions were deleted from
the 2012 and additional duplications were removed in
the 2015 IBC
5
IBC Special Inspection
The Special Inspection requirements in Chapter 17 of
the 2015 (and the 2012) IBC are quite different in
appearance than those in earlier editions of the
IBC, but in substance, the requirements are nearly
identical.
In essence, the 2009 and earlier IBC’s based their
provisions on the TMS 402/602 and tweaked them
in tables. Now, the 2012 & 2015 IBC simply
references the TMS 402/602
6
IBC Chapter 21
Section 2101 General
Section 2102 Definitions and Notations
Section 2103 Masonry Construction Materials
Section 2104 Construction
Section 2105 Quality Assurance
Section 2106 Seismic Design
Section 2107 Allowable Stress Design
Section 2108 Strength Design of Masonry
Section 2109 Empirical Design of Masonry
Section 2110 Glass Unit Masonry
Section 2111 Masonry Fireplaces
Section 2112 Masonry Heaters
Section 2113 Masonry Chimneys
7
IBC Section 2107: ASD
IBC Section 2107 requires compliance with TMS
402 Chapter 8, except for:

Modifies splice & development lengths. Allows a
simpler procedure, and in some cases is more
conservative and in some cases less
conservative than the TMS 402

Has additional requirements for mechanical and
welded splices


ASTM A706 steel required for welded lap splices.

ACI 318 Type 1 or 2 mechanical splices required.
Limits the maximum bar size to No. 9.
8
IBC Section 2107: ASD

Lap Splice Detailing Requirements for allowable stress design:

ld = 0.002 db Fs

ld = 64 db (for Grade 60 reinforcement)

Increase lap length by 50% when the computed
stress in reinforcement is 80 % or more of the
allowable stress in reinforcement (Fs).
9
IBC Section 2108: SD
IBC Section 2108 requires compliance with TMS 402
Chapter 9, except:

Splice and development lengths capped at 72 db


for No. 7 and larger bars, the 72 db cap governs, and the
IBC gives a shorter splice length than the TMS 402.
Has additional requirements for mechanical and
welded splices

ASTM A706 steel required for welded lap splices.

ACI 318 Type 1 or 2 mechanical splices required.
10
Last Thoughts: I - Codes

The IBC references standards such as the TMS
402/602 and ASCE 7. The IBC cannot be used
without those other standards.

The 2006 IBC made some modifications to the
TMS 402/602.

The 2009 IBC made no major modifications to the
2008 TMS 402/602. And it removed redundant
transcribed text, so that modifications are now
much easier to find.

2012 and 2015 IBC’s rely on TMS 402/602 even
more.
11
TMS 402/602

TMS 402 “Code”




Design provisions are given in Chapters 1 - 14 and
Appendices A, B and C
Sections 1.2.4 and Chapter 3 require a QA program in
accordance with the Specification
Section 1.4 invokes the Specification by reference.
TMS 602 “Specification”


verify compliance with specified fm comply with required
level of quality assurance
comply with specified products and execution
12
TMS 402/602
1988: First edition
1995: Seismic requirements moved from Appendix to main body of
code; chapter on veneers added; chapter on glass block added
1998: Major reorganization of code; prestressed masonry chapter
added
2002: Strength design chapter added; definitions of shear walls added
to correspond to IBC definitions; code moved to a three year
revision cycle
2005: Changed lap splice requirements, requiring much longer lap
lengths
2008: Major reorganization of seismic requirements; added AAC
masonry in Appendix
2011: Eliminated one-third stress increase and recalibrated allowable
stresses; added infill provisions in Appendix
2013: Changes for partially grouted shear walls; updated unit strength
table; limit states appendix
13
Why a 2 Year Cycle From 2011 to
2013?

ICC rule changes forced Standards Developers
to modify their revision cycle to allow additional
time to review standards before incorporation into
the IBC.

To react to these changes, the 2013 TMS
402/602 was developed in a shortened cycle to
allow adoption by the 2015 IBC. The end results:


The 2013 TMS 402/602 has been adopted by the 2015
IBC/IRC
The next edition is targeted for 2016 to get back on the
3-year revision cycle
14
Why the Name Change to TMS 402/602



In the past, the “MSJC” was developed by TMS, ACI and
ASCE. Good arrangement, but multiple names confused
some, and many wanted to see the document reflect the
work of TMS, the lead sponsor
In late 2013, ACI and ASCE relinquished their rights to
future editions so that it will now be called the TMS 402/602,
much like ACI 318 identifies the concrete code.
To start re-education, we’ll use TMS 402/602 when referring
to the 2013 edition, and the MSJC when referring to the
Committee or earlier editions
15
2011 TMS 402
MSJC
TMS 602
Ch. 1 - General Requirements
Ch. 2
Allowable
Stress
Design
Ch. 3
Strength
Design
Ch. 4
Prestressed
Masonry
3.1 - General SD
3.2 - URM
3.3 - RM
2.1 - General ASD
2.2 - URM
2.3 - RM
Ch. 5
Empirical
Design
Ch. 6
Veneer
Ch. 7
Glass
Block
6.1 - General
6.2 - Anchored
6.3 - Adhered
2011 TMS 402 also included a new Appendix
for Design of Masonry Infill
16
Ch. 8 AAC
2013 TMS 402 (Reorganized)
Part 1: General
Part 2: Design
Requirements
Part 3:
Engineered
Design Methods
Part 4:
Prescriptive
Design Methods
Part 5:
Appendices &
References
Chapter 1 –
General
Requirements
Chapter 4: General
Analysis & Design
Considerations
Chapter 8: ASD
Chapter 12:
Veneer
Appendix A –
Empirical Design
of Masonry
Chapter 2 –
Notations &
Definitions
Chapter 5:
Structural
Elements
Chapter 9: SD
Chapter 13: Glass
Unit Masonry
Appendix B:
Design of Masonry
infill
Chapter 3 –
Quality &
Construction
Chapter 6:
Reinforcement,
Metal Accessories
& Anchor Bolts
Chapter 10:
Prestressed
Chapter 14:
Masonry Partition
Walls
Appendix C: Limit
Design of Masonry
Chapter 7: Seismic
Design
Requirements
Chapter 11: AAC
References
17
2013 TMS 602
TMS 402 Code
TMS 602
Specification
Part 1
General
Part 2
Products
Part 3
Execution
1.6 Quality
assurance
2.1 - Mortar
2.2 - Grout
2.3 – Masonry Units
2.4 – Reinforcement
2.5 – Accessories
2.6 – Mixing
2.7 - Fabrication
3.1 - Inspection
3.2 - Preparation
3.3 – Masonry erection
3.4 – Reinforcement
3.5 – Grout placement
3.6 – Prestressing
3.7 – Field quality control
3.8 - Cleaning
18
TMS 402 Part 1 General Requirements

Ch. 1: Scope, Contract documents and
calculations, Special Systems, Reference
Standards

Ch. 2: Notation, Definitions

Ch. 3 Quality & Construction
Requires a quality assurance program in
accordance with the Specification



three levels of quality assurance (A, B, C)
increasing levels of quality assurance require
increasingly strict requirements for inspection, and for
compliance with specified products and execution
19
TMS 402 (& IBC) QA Requirements
Required Tests and Submittals
Masonry material certificates
′
Verify 𝑓𝑚′ & 𝑓𝐴𝐴𝐶
prior to
construction**
Level A*
Level B
Level C
•
•
•
•
•
′
Verify 𝑓𝑚′ & 𝑓𝐴𝐴𝐶
every 5,000 sq. ft.
during construction**
•
Verify proportions of materials in
premixed or preblended mortar &
grout
•
Verify slump flow & VSI of SCG
*Exempt from IBC
•
•
Periodic Continuous
** For Engineered masonry and not for Veneer, Glass United Masonry or Empirically Designed Masonry
20
TMS 402 (& IBC) QA Requirements
Minimum Special Inspection for Traditional Masonry*
Verify compliance with approved submittals
Level A Level B Level C
PT
PT
PT
Verify proportions of site-prepared mortars
Construction of mortar joints
Placement of masonry units
Location of reinforcing, connectors and anchorages
-
PT
PT
PT
PT
PT
PT
FT
Grout space (prior to grouting)
Grade, type, and size of reinforcing, anchor bolts & anchorages
-
PT
PT
FT
FT
-
PT
PT
FT
FT
-
PT
PT
PT
FT
FT
FT
Verify proportions of site-prepared grout
Size, type & location of attachments to other structural elements
Size and location of structural elements
Observe preparation of prisms and grout or mortar specimens
Grout Placement
* Does not include Prestressed masonry, Hot & Cold Weather requirements, etc. Refer to MSJC for specific Requirements
•PT – Part Time or Periodic
FT – Full Time or Continuous
21

Restricts pour height
based on width/space
minus horizontal
reinforcement which
restricts the space
Grout Pour
Grout space
requirements in Table
3.2.1 are intended to
provide adequate
room for placement of
grout.
Grout Lift

Grout Lift
TMS 402 Section 3.2: Construction
22
TMS 402 Part 2: Design Requirements

Ch. 4: General Analysis &
Design Considerations






4.1 Loading
4.2 Material properties
4.3 Section properties
4.4 Connections to structural
frames
4.5 Masonry not laid in
running bond

Ch. 6: Details of
reinforcement, metal
accessories & anchor bolts

Ch. 7 Seismic design
requirements
Ch. 5: Structural Elements
23
Masonry Building System
Walls parallel to lateral forces
act as shear walls to resist
in-plane loads; they may
resist axial loads
Bond beams transfer reactions
from walls to horizontal
diaphragms (floors and roof),
and act as diaphragm chords
Walls perpendicular to lateral forces resist moments
from out-of-plane loads and transfer reactions to
horizontal diaphragms; they may resist axial loads
24
TMS 402 Section 4.3: Section
Properties

Use minimum (critical) net area for computing
member stresses or capacities.

Radius of gyration and member slenderness are
better represented by the average section
25
TMS 402 Part 2: Design Requirements

Ch. 4: General Analysis &
Design Considerations

Ch. 5: Structural Elements





5.1 Masonry assemblies
5,2 Beams
5.3 Columns
5.4 Pilasters
5.5 Corbels

Ch. 6: Details of
reinforcement, metal
accessories & anchor bolts

Ch. 7 Seismic design
requirements
26
TMS 402 5.1.1: Wall Intersections
nominal flange
thickness, t
50%
interlocking
units
L = 6 t for compression or
unreinforced masonry in
tension
L = 3/4 floor - to - floor wall effective flange
height for reinforced
length, L
masonry in tension
wall to the right
of movement
joint not part of
flange of web
wall
movement
joint
27
TMS 402 5.1.2: Effective Comp. Width

For running - bond masonry, or masonry with bond
beams spaced no more than 48 in. center – to –
center, the width of compression area per bar for
stress calculations shall not exceed the least of:



Center - to - center bar spacing
Six times the wall thickness (nominal)
72 in.
28
TMS 402 5.1.3: Concentrated Load
Dist.

The critical area for walls laid in running bond shall
not exceed the wall thickness times the smaller of:


Length of bearing area plus a length determined by a
dispersion of 2 vertical: 1 horizontal. That dispersion is
limited by the smallest of one - half the wall height, a
movement joint, the end of the wall, or an opening.
Center – to – center distance between concentrated
loads
29
TMS 402 5.1.3: Concentrated Load
Dist.
Load
Load
Load
1
2
h
2
h/2
1
Effective Length
Effective Effective
Length Length
30
TMS 402 5.2: Beams

Span length equals clear span plus depth, but not
more than distance between support centers

Moments for continuous beams based on center to - center spans

Minimum bearing distance = 4 in.

Lateral support on compression face required at a
maximum spacing of 32 times the beam thickness
(nominal) but no more than 120b2/d

Must meet deflection limits of TMS 402 Section
5.2.1.4
31
TMS 402 5.3: Columns

Columns are defined in TMS 402
Section 5.3






ISOLATED member that primarily
resists compressive loads
h / r  99
Minimum side dimension: 8 in.
Minimum design eccentricity = 0.1 x t
0.25%  g  4.0%
At least 4 longitudinal bars, laterally
tied, except for lightly loaded columns
32
TMS 402 Part 2: Design Requirements

Ch. 4: General Analysis &
Design Considerations

Ch. 5: Structural Elements

Ch. 6: Details of
reinforcement, metal
accessories & anchor bolts

Ch. 7 Seismic design
requirements
33
TMS 402 6.1: Reinforcement

reinforcing bars must be
embedded in grout; joint
reinforcement can be
embedded in mortar

placement of
reinforcement

protection for
reinforcement

standard hooks
34
TMS 402 6.2: Anchor Bolts

Tensile capacity governed by

tensile breakout
 tensile pullout
 yield of anchor in tension
Shear capacity governed by

shear breakout
 masonry crushing
 shear pryout
 yield of anchor in shear
For combined tension and
shear, use linear interaction



Headed bolts, J bolts or L - bolts

Must be
embedded in
grout
35
TMS 402 Part 2: Design Requirements

Ch. 4: General Analysis &
Design Considerations

Ch. 5: Structural Elements

Ch. 6: Details of
reinforcement, metal
accessories & anchor bolts

Ch. 7 Seismic design
requirements
36
Shear Walls: Minimum Reinforcement
SW Type
Minimum Reinforcement
SDC
Empirically
Designed
none
A
Ordinary Plain
none
A, B
Detailed Plain
Vertical reinforcement = 0.2 in.2 at corners, within 16
in. of openings, within 8 in. of movement joints,
maximum spacing 10 ft; horizontal reinforcement W1.7
@ 16 in. or #4 in bond beams @ 10 ft
A, B
Ordinary
Reinforced
same as above
A, B, C
Intermediate
Reinforced
same as above, but vertical reinforcement @ 4 ft
A, B, C
Special
Reinforced
same as above, but horizontal reinforcement @ 4 ft,
and  = 0.002
any
37
TMS 402: Chapter 7

Seismic Design Category A



drift limit of 0.007 from ASCE 7 - 10 (Section 12.12.1)
for typical masonry structures
minimum design connection force for wall - to roof
and wall - to - floor connections from ASCE 7 - 10
(Section 12.11.2)
Seismic Design Category B

lateral force – resisting system cannot be designed
empirically
38
TMS 402: Chapter 7

Seismic Design Category C


Shear walls must meet minimum prescriptive
requirements for reinforcement and connections
(ordinary reinforced, intermediate reinforced, or
special reinforced)
Other walls must meet minimum prescriptive
requirements for horizontal or vertical reinforcement
39
TMS 402: SDC C Ordinary Walls
roof connectors
@ 48 in. max oc
roof
diaphragm
#4 bar (min) within
16 in. of top of parapet
Top of Parapet
#4 bars around
openings
#4 bar (min)
within 8 in. of
corners &
ends of walls
24 in. or 40 db
past opening
#4 bar (min) @
diaphragms
continuous
through control
joint
#4 bar (min)
within 8 in. of
all control joints
control joint
#4 bars @ 10 ft oc
#4 bars @ 10 ft oc or W1.7 joint
reinforcement @ 16 in. oc
40
TMS 402: Chapter 7

Seismic Design Category D




Masonry that is part of the lateral force – resisting
system must be reinforced so that v + h  0.002,
and v and h  0.0007
Type N mortar and masonry cement mortars are
prohibited in the seismic force – resisting system
Shear walls must meet minimum prescriptive
requirements for reinforcement and connections
(special reinforced)
Other walls must meet minimum prescriptive
requirements for horizontal and vertical reinforcement
41
TMS 402: Special Shear Walls
roof connectors
@ 48 in. max oc
roof
diaphragm
#4 bar (min) within
16 in. of top of parapet
Top of Parapet
#4 bars around 24 in. or 40 db
openings
past opening
#4 bar (min)
within 8 in. of
corners &
ends of walls
#4 bar (min) @
diaphragms
continuous
through control
joint
#4 bar (min)
within 8 in. of
all control joints
control joint
#4 bars @ 4 ft oc
#4 bars @ 4 ft oc
42
TMS 402 Chapter 8: ASD

calculated stresses from ASD loading
combinations must not exceed allowable
stresses

allowable stresses are failure stresses, divided
by a factor of safety varying from 2.5 to 4


calculated stresses: lower – case letters;
allowable stresses: upper – case letters
1/3 increase NO LONGER PERMITTED in
allowable stresses. Allowable stresses were
recalibrated with 2011 & 2013 TMS 402.
43
TMS 402 8.1: General

8.1.1 Scope

8.1.2 Design strength

8.1.3 Anchor bolts embedded in grout

8.1.4 Shear stress in multiwythe masonry
elements

8.1.5 Bearing stress

8.1.6 Development of reinforcement embedded
in grout
44
TMS 402 8.1.3.3: Anchor Bolts Tension
Bab  1.25 Apt
f m'
(8 - 1) and (8 - 3)
Bap  0.6 f ed d b  120  lb  ed  d b  d b
'
m
Bas  0.6 Ab f y
(8 - 4)
(8 - 2) and (8 - 5)
45
TMS 402 8.1.3.3: Anchor Bolts - Shear
Same for Bent Bars and for Headed Bolts
 shear breakout
Bvb  1.25 Apv

(8 - 6)
f Ab
(8 - 7)
masonry crushing
Bvc  350

f m'
4
'
m
shear pryout
Bvpry  2.0 Bab  2.5 Apt

f m'
(8 - 8)
steel yield
Bvs  0.36 Ab f y
(8 - 9)
46
TMS 402 8.1.3.3: Tension and Shear

Anchor bolts subjected to combined
shear and tension must satisfy a linear
interaction equation
ba
bv

1
Ba
Bv
(8  10)
47
TMS 402 8.1.6: Development and
Splice

Required embedment length in tension
addresses splitting from bar to surface and bar
to bar
ld 

0.13 d b2 f y 
K
f m'
 12 in. (bars) , 6 in. (wires) (8 - 12)
For epoxy – coated bars or wires, increase the
above values by 50%
48
TMS 402 8.2: ASD Unreinforced
Masonry

8.2.1
Scope

8.2.2
Design criteria

8.2.3
Design assumptions

8.2.4
Axial compression and flexure

8.2.5
Axial tension

8.2.6
Shear
49
TMS 402 8.2: Axial Compression

Depends on slenderness (h / r)
2

 h  
h
1 '
  for  99
Fa    f m 1  
r
 4    140 r  
 1   70 r 
Fa    f m' 

4  h 

2
for
h
 99
r
(8 - 16)
(8 - 17)
Also requires a stability check
P  (1 / 4) Pe
Pe 
(8 - 15)
 Em I 
2
h
2
e
1  0.577 
r

3
(8 - 19)
50
TMS 402 8.2: Axial and Flexure

Flexural compression
1 '
Fb    f m
3

Flexural tension (Table 8.2.4.2)





out - of - plane bending (traditional values)
lower values for masonry cement and air - entrained
portland cement - lime mortar
higher values for grouted masonry
Factors of safety around 2.5
Values for in – plane and out - of - plane flexural
tension are equal
51
TMS 402 8.2: Shear

Calculated shear stress
VQ
fv 
In b

(8 - 20)
Allowable stress is lowest of
1.5
f m'  120 psi
Nv
  0.45
An
Where  = 37 psi running bond or not running bond and
fully grouted, = 60 psi for running bond and grouted , and =
15 psi otherwise
52
TMS 402 8.3: ASD Reinforced

8.3.1
Scope

8.3.2
Design assumptions

8.3.3
Steel reinforcement

8.3.4
Axial compression and flexure

8.3.5
Shear
53
TMS 402 8.3: Allowable Stresses

Tension


Grade 60
Wire joint reinforcement
32,000 psi
30,000 psi

Maximum compressive stress in masonry from
axial load plus bending must not exceed 0.45f’m

Axial
2

h
 h  
'
Pa  (0.25 f m An  0.65 Ast Fs ) 1  
for
 99
 
r
  140r  
 70r 
Pa  (0.25 f m' An  0.65 Ast Fs ) 

 h 
2
for
h
 99
r
54
TMS 402 8.3: Shear

Shear stress is computed as:
V
fv 
Anv

(8 - 24)
Allowable shear stresses
Fv  Fvm  Fvs   g
(8 - 25)
 g 10.75 for partially grouted shear walls, 1.0 otherwise.
55
TMS 402 8.3: Shear

Allowable shear stresses limits:

M / Vdv ≤ 0.25
Fv   3 f m'  g


 M / Vdv  1
Fv   2 f m'  g



(8 - 26)
(8 - 27)
Can linear interpolate between limits
2

M
   g
Fv    5  2
3

Vd
v




56
TMS 402 8.3: Shear

Allowable Shear Stress Resisted by the Masonry

Special Reinforced Masonry Shear Walls
 
Fv  1


P
 M  '
4  1.75
f m  0.25 , (8 - 29)



4 
An
 Vd v 
All other masonry
 
Fv  1

P
 M  '
4  1.75
f m  0.25 , (8 - 28)



2 
An
 Vd v 
M/Vdv is positive and need not exceed 1.0.
57
TMS 402 8.3: Shear

If allowable shear stress in the masonry is
exceeded then:

design shear reinforcement using Equation 8-30
and add Fvs to Fvm
 Av Fs d v
Fvs  0.5
 Anv s





(8 - 30)
Shear reinforcement is placed parallel the direction of the
applied force at a maximum spacing of d/2 or 48 in.
One - third of Av is required perpendicular to the applied
force at a spacing of no more than 8 ft.
58
TMS 402 Chapter 9: SD

Design strength must exceed required strength
Action
Reinforced Masonry
combinations of
flexure and axial
load
0.90
Unreinforced
Masonry
0.60
shear
0.80
0.80
bearing
0.60
0.60
59
TMS 402 9.1: General









9.1.1 Scope
9.1.2 Required strength
9.1.3 Design strength
9.1.4 Strength-reduction factors
9.1.5 Deformation requirements
9.1.6 Anchor bolts embedded in grout
9.1.7 Shear strength in multiwythe masonry
elements
9.1.8 Nominal bearing strength
9.1.9 Material Properties
60
TMS 402 9.2: SD Unreinforced Masonry

9.2.1
Scope

9.2.2
Design criteria

9.2.3
Design assumptions

9.2.4
Nominal axial compression and flexure

9.2.5
Axial tension

9.2.6
Nominal shear strength
61
TMS 402 9.3: SD Reinforced

9.3.1
Scope

9.3.2
Design assumptions

9.3.3
Reinforcement requirements and details,
including maximum steel percentage

9.3.4
Design of piers, beams and columns


nominal axial and flexural strength
nominal shear strength

9.3.5
Wall design for out – of – plane loads

9.3.6
Wall design for in – plane loads
62
TMS 402 9.3.2: Design assumptions

continuity between reinforcement and grout

equilibrium

mu = 0.0035 for clay masonry, 0.0025 for
concrete masonry


plane sections remain plane
elasto – plastic stress – strain curve for
reinforcement

tensile strength of masonry is neglected

equivalent rectangular compressive stress block
of stress 0.80 𝑓𝑚′ and depth of 0.80c
63
TMS 402 9.3.3: Reinforcement

Bar diameter  1/8 nominal wall thickness

Standard hooks and development length

development length based on pullout and splitting

In walls, shear reinforcement must be bent around
extreme longitudinal bars

Splices


lap splices based on required development length
welded and lap splices must develop 1.25 fy
64
TMS 402 9.3.3.5: Maximum
reinforcement


No upper limit when Mu/(Vudv) ≤ 1 and R ≤ 1.5
Other members, maximum area of flexural tensile
reinforcement determined based on:





Strain in extreme tensile reinforcement = 1.5 εy
Axial forces determined from D + 0.75L + 0.525QE
Compression reinforcement, with or without lateral
restraining reinforcement, permitted to be included.
Intermediate shear walls with Mu/(Vudv) ≥ 1, strain
in extreme tensile reinforcement = 3εy
Special shear walls with Mu/(Vudv) ≥ 1, strain in
extreme tensile reinforcement = 4εy
65
TMS 402 9.3.3.5: Maximum
reinforcement
Three methods for checking maximum reinforcement

Commentary equations


Determine location of neutral axis based on specified
strain condition


only applicable for certain cases
Find axial capacity and check that axial force from D + 0.75L +
0.525QE is less than axial capacity
Determine location of neutral axis for given axial force,
compute strain in extreme tension steel, and compare to
minimum strain

Usually requires using trial and error to find the location of the
neutral axis
66
TMS 402 9.3.3.7: Joint reinforcement

Seismic Design Categories (SDC) A and B
 At least two 3/16 in. wires
 Maximum spacing of 16 in.

SDC C, D, E, and F; partially grouted walls
 At least two 3/16 in. wires
 Maximum spacing of 8 in.

SDC C, D, E, and F; fully grouted walls
 At least four 3/16 in. wires
 Maximum spacing of 8 in.
67
TMS 402 Chapter 9.3.4: Shear

Vn = (Vnm + Vns) γg

Vn shall not exceed:



4
Mu


Vn    5  2
Vu d v
3






Vn  6 Anv f m  g
Mu / Vu dv  0.25
Mu / Vu dv  1.0
Vn  4 Anv f m  g
linear interpolation between these extremes

 Anv


f m  g

objective is to avoid crushing of diagonal strut
γg – 0.75 for partially grouted shear walls and 1.0
otherwise
68
TMS 402 Chapter 9.3.4: Shear

Vnm and Vns are given by
Vnm

 Mu
 4.0  1.75
 Vu d v


 Anv

f m'  0.25 Pu
 Av 
Vns  0.5   f y d v
 s 
(9  24)
(9  25)
 Mu 

  1.0
 Vu d v 
69
TMS 402 Chapter 9.3.4.2: Beams

Pu  0.05 An fm

Mn  1.3 Mcr

Unless As provided is at least 1/3 greater than required

Maximum reinforcement: εs  1.5 εy

Concrete masonry, f ʹm = 2000 psi, Grade 60 steel

ρmax = 0.00952
70
TMS 402 Chapter 9.3.5: Out-of-Plane

Capacity under combinations of flexure and axial
load is based on the assumptions of TMS 402
Section 9.3.2 (interaction diagram)

Single layer of steel, equivalent stress block in face
shell or fully grouted.
a

As f y  Pu / 
0.80 f m b
t sp 
 t sp  a 

  As f y  d  
M n  Pu /   As f y 
2
 2 

For centered flexural reinforcement
a

M n  Pu /   As f y  d  
2

71
TMS 402 Chapter 9.3.5: Out-of-Plane

Maximum reinforcement by 9.3.3.5

Nominal shear strength by 9.3.4.1.2

Three procedures for computing out – of –
plane moments and deflections



Second – order analysis
Moment magnification method (new)
Complementary moment method; additional
moment from P – δ effects
72
TMS 402 Chapter 9.3.5: Out-of-Plane

Moment Magnification
M u   M u ,0
1
 
Pu
1
Pe
Pe 
 2 Em I eff
h
2

Mu < Mcr: Ieff = 0.75In

Mu ≥ Mcr: Ieff = Icr
(9  31)
(9  32)
(9  33)
73
TMS 402 Chapter 9.3.5: Out-of-Plane

Complementary Moment
wu h 2
eu
Mu 
 Puf
 Pu u
8
2
Pu  Puw  Puf
5M u h 2
u 
48 Em I n
(9  27)
(9  28)
(9  29)
5M cr h 2 5M u  M cr h 2
u 

48 Em I n
48 Em I cr

Eq. 9-29 for Mu < Mcr

Eq. 9-30 for Mu ≥ Mcr
(9  30)
74
TMS 402 Chapter 9.3.6: In-Plane

Capacity under combinations of flexure and axial
load is based on the assumptions of TMS 402
Section 9.3.2 (interaction diagram)
Pn
PLAN VIEW
Strain
εm
Stress
Mn
c
0.8fʹm
εs
75
TMS 402 Chapter 9.3.6: In-Plane

Maximum reinforcement by 9.3.3.5

Vertical reinforcement not less than one–half the
horizontal reinforcement

Nominal shear strength by 9.3.4.1.2
76
TMS 402 Chapter 9.3.6: In-Plane

Alternative approach to maximum reinforcement

For walls expected to have flexural ductility in plane, provide confined boundary elements in
hinging regions (another way of preventing toe
crushing)

Detailing requirements for boundary elements have
yet to be developed
77
TMS 402 Chapter 9.3.6: In-Plane

Alternative approach to maximum reinforcement

Provide confined boundary elements in hinging
regions (another way of preventing toe crushing)

Detailing requirements for boundary elements have
yet to be developed

Boundary elements not required if:
Pu  0.1 f m A g
geometrically symmetrical sections
Pu  0.05 f m A g
geometrically unsymmetrical sections
AND
Mu
1
Vu l w
OR
Vu  3 An
f m
AND
Mu
3
Vu lw
78
TMS 402 Chapter 10: Prestressed

Prestressed masonry
provisions were introduced in
the 1999 TMS 402, and
extensively updated in the
2005 TMS 402

Provisions address bonded
and unbonded tendons

Provisions address laterally
restrained and laterally
unrestrained tendons
79
TMS 402 Chapter 11: AAC Masonry

AAC (Autoclaved Aerated Concrete)

AAC is a lightweight, concrete - like material



strength is specified by strength class of the AAC material
alone (no prisms)


density from 25 to 50 pcf
compressive strength from 290 to 1100 psi
strength class is the specified compressive strength in MPa
(for example, Strength Class 4 has a specified compressive
strength of 4 MPa, or 580 psi)
AAC masonry units are laid using thin - bed, polymer modified mortar, which is stronger than the AAC material
itself
80
TMS 402 Chapter 12: Veneer

12.1 General


12.2 Anchored Veneer



12.1.1 to 12.1.6 Scope & General
design requirements
12.2.1 Alternate design method
12.2.2 Prescriptive requirements
12.3 Adhered Veneer


12.3.1 Alternate design method
12.3.2 Prescriptive requirements
81
TMS 402 Chapter 12: Anchored Veneer

Prescriptive requirements of
TMS 402 Section 12.2.2



Vertical support to meet TMS
402 Section 12.2.2.3
Thickness  2 – 5 / 8 in.
Anchor requirements in TMS
402 Section 12.2.2.5
 Corrugated sheet metal
anchors
 Sheet metal anchors
 Wire anchors
 Joint reinforcement
 Adjustable anchors and
spacings
82
TMS 402 Chap. 13: Glass Unit Masonry

Prescriptive requirements for





interior and exterior panels
isolated panels and continuous
bands
standard (3 – 7 / 8 in.) or thin
(3 – 1 / 8 in.) units
fm not required for glass unit
masonry designed by Chapter 13
Figure 13.2-1 sets maximum panel
areas for different design wind
pressures
83
TMS 402 Chap. 14: Partition Walls

New in 2013 TMS 402

Rationally based using engineering analysis

Includes prescriptive tables for 5 psf and 10 psf
lateral loads
Table 14.3.1(5) Maximum l/t1 and h/t1 for 5psf (.0.239 kPa) lateral load2
Mortar types
Unit and Masonry Type
Portland cement/lime or mortar
cement
Masonry cement or air entrained
portland cement/lime
M or S
N
M or S
N
Ungrouted and partially grouted hollow units3
26
24
22
18
Solid units and fully grouted hollow units3
40
36
33
26
1
t by definition is the nominal thickness of member
2 See Section 14.2.3.2
3 For non-cantilevered walls laterally supported at both ends. See Section 14.3.3 for
cantilevered walls.
84
Design Methods
Summary of design methods for
typical masonry elements
85
Beam and Lintel Design
Strength Design (Chapter 9)
Allowable Stress (Chapter 8)
• Allowable masonry stress: 0.45f’m
• Allowable steel stress
• 32 ksi, Grade 60 steel
k
2
j

1

k  (n )  2n  n
3
M
fs 
As jd
2M
fm 
b(kd )( jd )
• No min or max reinforcement
requirements
• Allowable shear stress
1
Fvm  2.25 f m
2
•
•
•
•
•
mu = 0.0035 clay masonry
mu = 0.0025 concrete masonry
Masonry stress = 0.8f’m
Masonry stress acts over a = 0.8c
 = 0.9 flexure; 0.8 shear

1 As f y 

M n  As f y  d 

2 0 .8 f m b 

Vn  2.25 Anv f m
• Minimum reinf: Mn ≥ 1.3Mcr
• or As ≥ (4/3)As,req’d
• Maximum reinf: s ≥ 1.5y
 max 
0.80.8 f m   m 


fy
 m  s 
86
Beam and Lintel Design
Allowable Stress (Chapter 8)
1. Assume value of j (or k).
Typically 0.85 < j < 0.95.
2. Determine a trial value of As.
𝐴𝑠 = 𝑀/ 𝐹𝑠 𝑗𝑑
Choose reinforcement.
3. Determine k and j; steel stress
and masonry stress.
4. Compare calculated stresses to
allowable stresses.
5. If masonry stress controls design,
consider other options (such as
change of member size, or
change of f’m). Reinforcement is
not being used efficiently.
Strength Design (Chapter 9)
1. Determine a, depth of compressive
stress block
a  d  d2 
2. Solve for As
As 
2M n
0.8 f m b
0.8 f m ba
fy
3. ρmax = 0.285 𝑓𝑚′ 𝑓𝑦 for CMU
Grade 60, f’m = 2 ksi
ρmax = 0.00952
87
Beam and Lintel Design
Assume compression controls.
Determine kd.
2


d
d
2
M



kd  3    
2
 2  3Fbb 


If k < kb tension controls. Use iterative
procedure to solve cubic equation. Start
with kd from compression controlling.
As 
If k ≥ kbal compression controls.
kbal 
Fb
Fb 
Fs
n
Grade 60 steel
kbal = 0.312
Determine As.
Fb (kd )b
2
As 
1 
nFb   1
k 
 
M
 k
Fs d 1  
 3
 As Fs n
Fs b
kd 2 
 2  2d  
Iterate. Use (kd)2 as new
guess and repeat.
88
Interaction Diagrams
Allowable Stress (Chapter 8)
• For k > kbal
• Set masonry strain = Fb/Em;
= 0.0005 CMU
• Find steel strain
• For k < kbal
• Set steel strain = Fs/Es;
= 0.00110 for Grade 60
• Find masonry strain
• Allowable axial load
• h/r ≤ 99
  h 2 
Pa  0.25 f m An  0.65 Ast Fs 1  
 
140
r
 
 
Strength Design (Chapter 9)
• Set masonry strain to εmu
• Vary steel strain
• Equivalent rectangular stress block
• Nominal axial strength
• h/r ≤ 99
  h 2 
Pn  0.8 0.80 f m  An  Ast   f y Ast 1  
 
  140r  


• h/r > 99


 70r 
Pn  0.80 0.80 f m  An  Ast   f y Ast 

 h 
• =0.9
• h/r > 99
 70r 
Pa  0.25 f m An  0.65 Ast Fs 

 h 
2
89
2
Combined Bending and Axial Load
Allowable Stress (Chapter 8)
Assume compression controls.
Determine kd.
2


d
d
2
(
P
(
d

t
/
2
)

M
)



kd  3    
2
3Fbb

2


If k ≥ kbal compression controls.
Strength Design (Chapter 9)
If steel has yielded
a  d  d2 
2Pu d  t / 2  M u 
 0.8 f m b
0.8 f m ba  Pu / 
As 
fy
Fb (kd )b
P
2
As 
1 
nFb   1
k 
If k < kb tension controls. Iterate
to find As.
90
Combined Bending and Axial Load
ASD, continued
If k < kb tension controls. Use iterative procedure to solve cubic equation. Start
with kd from compression controlling.
 t kd 
M   P  
2 3 
As 
 
M M
 k
Fs d 1  
 3
P  As Fs n
kd 2 
Fs b
 2  2d  
Iterate. Use (kd)2 as new guess and repeat.
91
Bearing Walls – OOP Loads
Allowable Stress
(Chapter 8)
• No second-order
analysis required
• Use previous design
procedure
Strength Design (Chapter 9)
•
•
•
•
Second order analysis required
Assumes simple support conditions
Assumes uniform load
Assumes midheight moment is
approximately maximum moment
• Valid only for following conditions:
𝑃
• 𝑢 ≤ 0.05𝑓𝑚′ No height limit
•
𝐴𝑔
𝑃𝑢
≤ 0.20𝑓𝑚′
𝐴𝑛
ℎ
≤ 30
𝑡
height limited by
• Need to check maximum
reinforcement limits
92
Strength Design – OOP Loads
Deflection:
Moment:
wu h 2
eu
Mu 
 Puf
 Pu u
8
2
Pu  Puw  Puf
5M u h 2
u 
48 Em I n
5M cr h 2 5M u  M cr h 2
u 

48 Em I n
48 Em I cr
Puf = Factored floor load
Puw = Factored wall load
3

t sp 
P
bc
2
u
d  c  
I cr  n As 

f y 2d 
3

Deflection Limit
M u  M cr
 s  0.007h
c
M u  M cr
As f y  Pu
0.64 f 'm b
Calculated using allowable
stress load combinations
93
Strength Design – OOP Loads
Solve simultaneous linear equations:
Mu > Mcr
Mu < Mcr
wu h 2
eu 5M cr Pu h 2  1
1 
 

 Puf

8
2
48 Em  I n I cr 
Mu 
5 Pu h 2
1
48 Em I cr
u 
5h 2
48 Em I cr
 wu h 2
 I cr

eu
 Puf
 M cr 
 1

2
 8
 In

5 Pu h 2
1
48 Em I cr
wu h 2
e
 Puf u
2
Mu  8
5 Pu h 2
1
48 Em I n
u 
 wu h 2
eu 
 Puf 

8
2

5 Pu h 2
1
48 Em I n
5h 2
48 Em I n
94
Shear Walls - Shear
Allowable Stress (Chapter 8)
Fv  Fvm  Fvs
Fvm 
Fvm
 M
1 

4
.
0

1
.
75

2 
 Vd v


P
  f m   0.25

An


Strength Design (Chapter 9)

 M
Vnm  4.0  1.75 u

 Vu d v
 M
1 
  4.0  1.75
4 
 Vd v


P

 f m   0.25

An


Special Reinforced Shear Walls
AFd
Fvs  0.5 v s 
 An s 
Fv  3 f m
Fv  2 f m
M / Vd v   0.25
M / Vd v   1.0
Interpolate for 0.25 < (M/Vdv) < 1
  0.8
Vn  Vnm  Vns

 Anv

f m  0.25 Pu
A 
Vns  0.5 v  f y d v
 s 
Vn  6 Anv
f m
M u / Vu d v   0.25
Vn  4 Anv
f m
M u / Vu d v   1.0
M 
4
Vn   5  2 u  Anv f m
3
Vu d v 
95
0.25 
Mu
 1.0
Vu d v
Shear Walls – Max Reinforcement
Allowable Stress (Chapter 8)
Special reinforced shear walls having
• M/(Vd) ≥ 1 and
• P > 0.05f′mAn
 max 
nf m
fy 

2 f y  n  
f m 

a = 1.5 ordinary walls; all others
a = 3 intermediate walls with Mu/(Vudv)≥1
a = 4 special walls with Mu/(Vudv)≥1
Strength Design (Chapter 9)
• Provide boundary elements, or
• Limit reinforcement
Boundary elements not required if:
symmetrical sections
Pu  0.1 f m A g
Pu  0.05 f m A g
unsymmetrical sections
AND
Mu
 1 OR
Vu l w
Vu  3 An f m
Mu
3
Vu lw
Reinforcement limits:
• Maximum stress in steel of αfy
• Axial forces D+0.75L+0.525QE
• Compression reinforcement, with or
without lateral ties, permitted to be
included
96
Shear Walls – Shear Capacity Design
Allowable Stress (Chapter 8)
Strength Design (Chapter 9)
• Seismic design load required
to be increased by 1.5 for
shear
• Design shear strength, Vn,
greater than shear
corresponding to 1.25 times
nominal flexural strength, Mn
(increases shear at least
1.39 times)
• Except Vn need not be
greater than 2.5Vu. (doubles
shear)
• Masonry shear stress
reduced for special walls
97
Significant Changes in the 2013 TMS
402/602
Major Technical Changes
• Partially grouted shear walls
• Moment magnifier method
• Unit strength tables
98
Partially Grouted Shear Walls:
In-Plane Shear Strength
ASD
8.3.5.1.2
Fv  Fvm  Fvs  g
SD V  V  V 
nm
ns
g
9.3.4.1.2 n
γg = 0.75 for partially grouted shear walls and 1.0 otherwise
𝑉𝑒𝑥𝑝𝑒𝑟𝑖𝑚𝑒𝑛𝑡𝑎𝑙
𝑉𝑛𝑜𝑚𝑖𝑛𝑎𝑙
Mean
St Dev
Fully grouted
1.16
0.17
Partially grouted
0.90
0.26
(Davis et al, 2010)
(Minaie et al, 2010)
0.90
 0.776
1.16
99
Partially Grouted Shear Walls:
In-Plane Shear Strength
Methods to calculate shear strength
of partially grouted shear walls
(Minaie et al, 2010)
𝑉𝑒𝑥𝑝𝑒𝑟𝑖𝑚𝑒𝑛𝑡𝑎𝑙
𝑉𝑛𝑜𝑚𝑖𝑛𝑎𝑙
Mean
St Dev
2008 MSJC Code
0.90
0.26
Multiply shear strength by An/Ag
1.53
0.43
Using just face shells
1.77
0.78
Calculate net area, Anv, including grouted cells.
Anv  2.5in192in   5(8in)(7.62in  2.5in)  685in 2
100
CMU Unit Strength Table
TMS 602 Table 2
Net area
compressive
strength of concrete
masonry, psi
Type M or S Mortar
Type N Mortar
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
----
Net area compressive strength of ASTM
C90 concrete masonry units, psi (MPa)
101
Specified Compressive Strength, f′m
Unit Strength (psi)
f′m (psi)
Type N mortar
Type S mortar
1900 psi (C90-12)
2011 TMS 402/602
1350
1500
1900 psi (C90-12)
2013 TMS 402/602
1700
1900
2000 psi (C90-14)
2013 TMS 402/602
1750
2000
2013 TMS 402/602 references ASTM C90-12.
To use f′m = 2000 psi (Type S), technically need to specify either:
• ASTM C90-14, or
• ASTM C90-12 but with a minimum unit strength of 2000 psi
102
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
103
8 in. CMU wall
Fully grouted
Grade 60 steel
Out-of-plane
loading
f′m = 2000 psi
•
•
•
•
f′m = 1500 psi
Maximum Reinforcement
Spacing (inches)
P/(bd)
(psi)
As (in2
per ft)
#4
#5
#6
0
0.326
8
16
16
100
0.250
16
16
24
200
0.174
16
24
32
300
0.098
24
40
56
400
0.022
112
176
248
P/(bd)
(psi)
As (in2
per ft)
#4
#5
#6
0
0.435
8
8
16
100
0.359
8
16
16
200
0.283
8
16
24
300
0.207
16
24
32
400
0.130
24
32
40
Spacing (inches)
104
Lap Splices
Splice Length (in)
Bar Size
2008 Code
f’m = 1500 psi
2011 Code
f’m = 1500 psi
2013 Code
f’m = 2000 psi
3
15
12
12
4
20
14*
12*
5
25
23*
20*
6
43*
43*
37*
7
59*
59*
52*
8
91*
91*
79*
9
118*
118*
103*
8 in. CMU: bars centered in wall; fy=60 ksi
* denotes K is controlled by masonry cover
105
Walls: Slenderness Effects
1. Complementary moment method
a. Second-order moment directly added by P-δ
b. Usually requires iteration
c. Difficult for hand calculations for other than simple cases
d. Basis for second-order analysis in computer programs
e. Historical method used for masonry design
2. Second-order analysis
a. Added in 2013 TMS 402 Code (9.3.5.4.3)
b. Computer analysis
3. Moment magnification method
a. Added in 2013 TMS 402 Code (9.3.5.4.3)
b. Very general, but a bit conservative.
106
Moment Magnifier Method
First Order
Moment w
h2
eu 5M cr Pu h 2  1 1 
  
 Puf

8
2
48 Em  I n I cr 
5 Pu h 2
1
48 Em I cr 5
u
Complementary
Moment
Mu 
48
M u  M u , 0
(Equation 9-31)
1

Pu
1
Pe
(Equation 9-32)
Pe 
 2 Em I eff
h2
(Equation 9-33)
Always
Negative
= 0.104 ~
1
= 0.101
𝜋2
Mu < Mcr: Ieff = 0.75In
Mu ≥ Mcr: Ieff = Icr
Moment magnifier is very
general; no limitations
107
Moment Magnifier, Deflections
Deflections determined either by:
1. Complementary moment method (simple support conditions)
2. Second-order analysis
3. First-order deflections magnified by 1/(1-P/Pe)
Helpful Hints:
Pf eh 2
5wh 4
0 

384 Em I e 16 Em I e
First-order deflection (simply supported wall):
Rewriting TMS 402 OOP equations:
Same as proposed by Bischoff, P. (2005).
”Reevaluation of Deflection Prediction for Concrete
Beams Reinforced with Steel and Fiber Reinforced
Polymer Bars.” J. Struct. Eng., 131(5), 752–767.
Ie 
I cr
M cr  I cr
1 
1
M 
In



108
Walls, OOP Loading, Summary
• Traditional “slender wall” method has been retained
• Two new options: very general
• Second-order analysis
• Moment magnification method
• Loophole:
• Second-order analysis methods allowed with no h/t or axial load
restriction
• Complementary moment method is a valid second-order analysis
method
• Therefore the restrictions on h/t and axial stress in 9.3.5.4.2 are
meaningless
109
Many More Changes
• Modulus of rupture values increased
• Joint reinforcement can be primary
shear reinforcement in strength design
• Reinforcement and mortar requirements
• Deep beam clarification
• ASTM C-90 Normalized web area
• Bond beams may be stepped or sloped
• Tolerances for initial bed joint
• Illustration of ‘d’ distance
110
Modulus of Rupture Values, Table
9.1.9.2
Masonry Type
Mortar Type
Portland cement/lime or
mortar cement
Normal to Bed Joints
Solid Units
Hollow Units*
Ungrouted
Fully Grouted
Parallel to bed joints in running bond
Solid Units
Hollow Units
Ungrouted and partially grouted
Fully grouted
Parallel to bed joints not laid in running bond
Continuous grout section parallel to
bed joints
Other
Masonry Cement
M or S
N
M or S
N
133
100
80
51
84
163
64
158
51
153
31
145
267
200
160
100
167
267
127
200
100
160
64
100
335
335
335
335
0
0
0
0
111
Modulus of Rupture: Effect of Increase
Example: 8 inch CMU, bars at 48 inch, Type S masonry cement
2011:
 5 ungrouted cells 
 1 grouted cell 
  153 psi 
f r  38 psi
  57 psi
6
cells
6
cells




2013:
 5 ungrouted cells 
 1 grouted cell 
  153 psi 
f r  51 psi
  68 psi
6
cells
6
cells




δ (inch)
Load Combination
Results from 18 ft high
bearing wall trial design:
out-of-plane loads
fr = 57 psi
fr = 68 psi
D+0.6W
0.70
0.55
0.6D+0.6W
0.65
0.50
D+0.75(0.6W)+0.75Lr
0.38
0.22
Primary impact is to reduce calculated
deflections under out-of-plane loading
112
Joint Reinforcement
• Seismic Design Categories (SDC) A and B
– At least two 3/16 in. wires (heavy duty joint reinforcement)
– Maximum spacing of 16 in.
• SDC C, D, E, and F; partially grouted walls
– At least two 3/16 in. wires
– Maximum spacing of 8 in.
• SDC C, D, E, and F; fully grouted walls
– At least four 3/16 in. wires
– Maximum spacing of 8 in.
Joint Reinforcement
Equivalent Reinforcement Options
Joint Reinforcement
Equivalent Bar
Reinforcement
Replaces this
Reinforcement
2 - 3/16 in. wires at 16 in.
0.0347 in2/ft
#4 @ 56in.; #5 @ 80 in.
2 – 3/16 in. wires at 8 in.
0.0694 in2/ft
#4 @ 32 in.; #5 @ 40 in.
4 – 3/16 in. wires at 8 in.
0.1388 in2/ft
#4 @ 16 in.; #5 @ 24 in.
Bar reinforcement yield stress = 60 ksi
Joint reinforcement yield stress = 70 ksi
Splice length: 48db
(9.3.3.4 (e))
Anchor around edge reinforcing bar, either by bar placement between
adjacent cross-wires or with a 90° bend in longitudinal wires and at
least 3-in. bend extensions. (9.3.3.3.2.3)
Reinforcement and Mortar
Reinforcement
• Mechanical splices in flexural reinforcement in plastic hinge zones of
special reinforced walls: required to develop the specified tensile
strength of the spliced bar, rather than 1.25fy (7.3.2.6 (e))
• Welded splices: reinforcement required to either conform to ASTM
A706, or a chemical analysis and carbon equivalent of the
reinforcement steel will need to be determined. (8.1.6.7.2, 9.3.3.4 (c))
Mortar
• Masonry cement mortar is now permitted for fully grouted
participating elements in Seismic Design Category (SDC) D and
higher. (7.4.4.2.2)
Deep Beam Clarification
Beam
depth
Alternative
beam
depth
00
leff
leff
ASTM C90: Normalized Web Area
ASTM C-90 reduced limits on web thickness of CMU
units and added normalized web area
Nominal
Width (in.)
Face Shell
Thickness
(in.)
Web
Thickness
(in.)
Normalized
Web Area
(in2/ft2)
3 and 4
¾
¾
6.5
6
1
¾
6.5
8
1–¼
¾
6.5
Shear stresses in web need to be checked with
unreinforced masonry if normalized web area is less
than 27 in.2/ft2. (8.2.6.3 ,9.2.6.2)
ASTM C90: Normalized Web Area
Advantages of reduced web area:
• Lighter weight units
• easier to lay
• minimal reduction in seismic weight, at least for partial grouted
• Easier to lay; do not have to lift over bars with A and H blocks
• Increased R-value of walls
• more insulation
• less thermal shorts
Caution:
• Reduces equivalent net thickness, which reduces fire ratings
Practical minimum normalized web area
to avoid breakage is about 11-12 in2/ft2.
http://www.fendtproducts
.com/products/concretemasonry-units/h-formblock.html
Tolerances for Initial Bed Joint
Footing tolerances
• Level alignment of footings: ± ½ in.
Does not work
2011 Bed joint tolerances
• Initial bed joint: ¼ in. to ¾ in.
Tolerance increased from ¾
in. to 1¼ in. when the first
course of masonry is solid
grouted and supported by a
concrete foundation.
Questions?