The Structures Group, Inc., a consulting engineering firm specializing in structural engineering, presented at Architectural Exchange East in November 2013. The presentation focused on the properties of brick veneer and special considerations for multi-story building designs.

1. Welcome to Architecture Exchange East 2013

2. Architecture Exchange East 2013
Virginia Society AIA is a registered provider with the American
Institute of Architects Continuing Education Systems. Credit earned
on completion of this program will be reported to CES Records for
AIA members. Certificates of completion for non-AIA members are
available on request.
This program is registered with the AIA/CES for continuing
professional education. As such, it does not include content that
may be deemed or construed to be an approval or endorsement by
the AIA of any material of construction or any method or manner of
handling, using, distributing, or dealing in any material or product.
Questions related to specific materials, methods, and services will
be addressed at the conclusion of this presentation.

3. Architecture Exchange East 2013
Combined Effects of Multi-Story Buildings
and Brick Veneer
Presented By:
Michael A. Matthews, P.E.
The Structures Group, Inc.

4. Speaker Bio
•
Mike Matthews is President and CEO of The Structures
Group, Inc., a consulting engineering firm with its corporate
office in Williamsburg, Virginia. He graduated from Virginia
Polytechnic Institute & State University in 1982 with a
degree in Civil (Structural) Engineering and received an MBA
from the College of William and Mary in 1988.
•
Mike is currently chairman of the ACEC/VA Professional
Development Committee and former chair of the Codes and
Regulations Committee. Mike has served on the VBCOA
Region Eight Special Inspections Task Force and is one of the
Co-Authors of National Practice Guidelines for the Structural
Engineer of Record (CASE, Fourth Edition) and the Hampton
Roads Regional Special Inspection Guidelines and
Procedures (2003, 2006, and 2009 USBC Editions).
•
The Structures Group, Inc. provides structural engineering,
forensic analysis, special inspections, independent code
review, and risk analysis services. The firm, as well as Mike,
is currently licensed to practice engineering in eighteen (18)
states, as well as the District of Columbia.

5. Our Goal Today Will Be To Illustrate:
•
Differing expansion and contraction properties of masonry
veneer and its backup
•
Building code requirements regarding masonry veneer and
expansion joints
•
Pros and cons of commonly used masonry veneer expansion
joint details
•
Need for collaboration between Architects and Structural
Engineers in developing construction documents and value
engineering related to masonry veneer

6. Volume Change of Clay Brick
The 2009 Edition of the Virginia Uniform
Statewide Building Code (VUSBC) adopts and
amends the 2009 Edition of the International
Building Code (IBC)
Chapter 21 of the IBC refers to: Building Code
Requirements for Masonry Structures (ACI
530-05)
Section 1.8: Material Properties of ACI 530
defines the coefficients for:
•
•
•
Temperature Expansion (Reversible)
Shrinkage (No curing shrinkage of clay brick)
Moisture Expansion

7. Volume Change of Clay Brick continued
As stated in Section 1.8 of ACI 530:
• Temperature Expansion (Reversible):
kt = 4 x 10-6 in/in/°F
Example:
ΔF = 100F
H or L=100’
Δt = L(12)(100)(ΔF)(Ke)
Expansion due to temperature Δt = 100(12)(100)(.000004)=0.48in

8. Volume Change of Clay Brick continued
As stated in Section 1.8 of ACI 530:
• Moisture Expansion (Non-reversible):
ke = 3 x 10-4 in/in
Example:
H or L = 100’
Δe = L(12)(Ke)
Expansion due to moisture Δe = 100(12)(.0003) = 0.36 in

9. Volume Change of Clay Brick continued
Summary of volume change:
•
Expansion due to temperature
– Δt = 100(12)(100)(.000004)= 0.48in
•
Expansion due to moisture
– Δe = 100(12)(.0003) = 0.36 in
•
Total Expansion of Brick
–
Δt + Δe = 0.84 in

10. Volume Change of Concrete Masonry
(CMU)
The 2009 Edition of the Virginia Uniform
Statewide Building Code (VUSBC) adopts
and amends the 2009 Edition of the
International Building Code (IBC)
Chapter 21 of the IBC refers to: Building
Code Requirements for Masonry Structures
(ACI 530-05)
CMU Backup
Section 1.8: Material Properties of ACI 530
defines the coefficients for:
•
•
•
•
Temperature Expansion (Reversible)
Moisture Expansion (Reversible)
Drying Shrinkage (Non-Reversible)
Creep
CMU Veneer

11. Volume Change of Concrete Masonry
(CMU) continued
As stated in Section 1.8 of ACI 530:
• Temperature Expansion (Reversible):
– kt = 4.5 x 10-6 in/in/°F
Example:
ΔF = 100F
H or L=33’
Δt = L(12)(ΔF)(Kt)
CMU Backup

12. Volume Change of Concrete Masonry
(CMU) continued
As stated in Section 1.8 of ACI 530:
• Drying Shrinkage (Non-Reversible):
– Km = 0.55 S1 ≈ ranges from 0.0002 – 0.00065 in/in
(S1 : Total linear drying shrinkage of concrete
masonry units determined in accordance with
ASTM C426)
Example:
H or L=33’
Δm = K m L(12)
Drying Shrinkage = .000425(33)(12) = 0.17 in.
CMU Backup
CMU Veneer

13. Volume Change of Concrete Masonry
(CMU) continued
Creep: Long-term deflection will be relative
to instantaneous deflection from sustained
loading. (Negligible) KL = 2.5 x 10-7 in/in/psi
Example:
Loads: Dead + Reduced Live (ASCE-7 Appendix C)
3rd Floor – 800 plf
2nd Floor – 1600 plf
1st Floor – 2400 plf
8” CMU reinforced with #6 bars at 24” on center
Creep: Δc = K l Ph/AE
3rd Floor – 0.0003 in
2nd Floor – 0.0008 in
1st Floor – 0.0011 in
Total Creep: Δc = 0.0003 + 0.0008 + 0.0011 =
0.0022 in

14. Volume Change of Concrete Masonry
(CMU) continued
As stated in Section 1.8 of ACI 530:
•
•
•
•
Expansion due to Temperature Δt = 100(12)(33)(.0000045)=0.18 in.
Drying Shrinkage = .000425(33)(12) = 0.17 in.
Moisture Expansion (Reversible): Value not given by ACI 530
Creep: Negligible
Total CMU wall Movement = Δt + Δm + ΔL
Temperature
Shrinkage
Creep
Total
0.18 inches
0.17 inches
0.0022 inches
0.3522 inches

15. Volume Change of Wood
Three directions of Wood Expansion and Shrinkage:
• Tangential
• Radial
• Longitudinal

16. Volume Change of Wood continued
Moisture Shrinkage: Timber is manufactured today at 19%
moisture content while equilibrium of timber is about 11% to 12%
• Tangential Shrinkage: Greatest Shrinkage
• Radial Shrinkage: Approximately 1/2 of tangential shrinkage
• Longitudinal Shrinkage: Very small and usually disregarded
Problem: Not knowing how wood grain is oriented

17. Volume Change of Wood continued
Simplified Method for Moisture Shrinkage Analysis:
• Horizontal Lumber (Joists, Truss Chords, and Plates)
– Shrinkage of dimensional lumber Δs: 0.2% shrinkage per 1% change in
moisture content (Δmc)
Example for horizontal members considering tangential and radial
shrinkage:
Joist
Plate
Δs =(0.002) d Δmc
d = 11.25 in (2 x 12 joist)
Δmc = 8 (moisture change in wood from
manufactured to equilibrium)
Δs = (0.002)(11.25)(8) = 0.18 inches
Δs =(0.002) d Δms
d = 1.5 in (2 x plate)
Δmc = 8 (moisture change in wood from
manufactured to equilibrium)
Δs = (0.002)(1.5)(8) = 0.024 inches
• Vertical Members (Studs, Columns, Web Members, and Truss Webs)
– Shrinkage of dimensional lumber: negligible Δs ≈ 0

18. Volume Change of Wood continued
Temperature Expansion: Radial and tangential depend on specific
gravity wood species
• Radial Expansion: αr = (18G + 5.5) * 10-6 per F
– Example: 10’-0” of southern pine (G = 0.55) experiencing 100F
temperature change: Δ=0.18”
• Tangential Expansion: αT= (18G + 10.2) * 10-6 per F
– Example: 10’-0” of southern pine (G= 0.55) experiencing 100F
temperature change: Δ=0.24”
• Longitudinal temperature change independent of specific gravity. Ranges
from αL= 0.0000017 to 0.0000025 per F
– Example: 10’-0” of long board subject to (100F temperature
change: Δ=0.03”

19. Volume Change of Wood continued
Moisture Expansion:
• Wood exposed to moisture will expand and shrink back
towards its original size, reversing the wood shrinkage
experienced.

20. Volume Change of Cast-in-Place Concrete
Three elements of movement involved in cast-in-place
concrete structures that need to be considered in design:
• Elastic Shortening
• Creep
• Shrinkage

21. Volume Change of Cast-in-Place
Concrete continued
The 2009 Edition of the Virginia Uniform
Statewide Building Code (VUSBC) adopts and
amends the 2009 Edition of the International
Building Code (IBC)
Chapter 21 of the IBC refers to: Building Code
Requirements for Masonry Structures (ACI
530-05)
Section 1.8: Material Properties of ACI 530
defines the coefficients for:
•
•
•
Elastic Shortening
Creep
Shrinkage

22. Volume Change of Cast-in-Place
Concrete continued
Elements of Concrete Frame Shortening
Elements
Time Dependent
Load Dependent
X

Creep


Shrinkage

X
Elastic Shortening

23. Volume Change of Cast-in-Place
Concrete continued

24. Volume Change of Cast-in-Place
Concrete continued
Magnitude of long term concrete volume changes (Per ACI 209)
• Elastic Shortening: The instantaneous deflection in the concrete frame due to
applied loads.
• Creep, νu : 2.35 times the instantaneous deflection experienced from
sustained loading. Reaches approximately 90% of total anticipated creep in
approximately 5 years.
• Shrinkage, (εsh): 780 γsh x 10-6 in./in., i.e. 0.078%. Reaches approximately 90%
of total anticipated shrinkage in approximately 1 year.
Example:
H or L = 100’
Δs = L(12)(εsh)
Shrinkage = 100(12)(0.00078) = 0.94 in.

25. Volume Change of Cast-in-Place
Concrete continued
Creep and Shrinkage (Per ACI 209)
Applied to creep coefficient and shrinkage strain to achieve more accurate
volume change prediction.
• Curing Conditions
– Specified Curing Processes
• Concrete Composition
– Concrete Mix Design
• Geometry
– Exposed Surface Areas
• Anticipated Loading
– Specified Live/Dead Loads
– Specified Length of Time for Shoring

26. Volume Change of Steel
Shelf Angles and Shelf Angle Flashing
Volume Change due to Temperature
• Coefficient of Expansion: 6.5 x 10-6 in./in./°F (Per the AISC Steel Manual)
– Example: 20’ long angle with 100 °F temperature change: Δ = 0.17 in

27. Volume Change of Steel continued
Expansion of steel shelf angles and metal flashing must
be accounted for.

28. What Happens When Movement of the
Veneer & Frame are not Accounted for
Examples of distress in masonry after construction

29. Example No. 1
Brick Veneer with Wood Frame Backing
ACI 530 Section 6.2.2.3.1.2 - Anchored
Veneer with a backing of wood
framing shall not exceed the height
above the noncombustible foundation
given in Table 6.2.2.3.1.
Maximum Height of Anchored Veneer with
Wood Backing
ACI 530 Table 6.2.2.3.1
Height at top plate
Height at gable
30’-0”
38’-0”

30. Example No. 1 Continued
Expansion of Brick Veneer and
Shrinkage of Wood Frame are additive:
Brick Veneer Expansion:
• Expansion due to temperature:
Δt = (33)(12)(100)(0.000004) = 0.16 in
• Expansion due to moisture:
Δc = (33)(12)(0.0003) = 0.12 in
Total anticipated expansion of brick
veneer: 0.28 inches

31. Example No. 1 continued
Expansion of Brick Veneer and
Shrinkage of Wood Frame are additive:
Wood Frame Shrinkage:
Example: 9’-0” ceiling and 2’-0” floor wood
truss framing for three (3) story building:
Per Floor:
• (1) 2x sill plate; (2) 2x top plates; (2)
2x chords from wood truss (Total of
(5) 2x plates per floor)
• Δs = (5 plates per floor)[(0.002)d Δms ]
= 0.12 inches per floor
Total anticipated shrinkage of wood
framing: 0.36 inches

32. Example No. 1 continued
Expansion of Brick Veneer and
Shrinkage of Wood Frame are additive:
Exterior Wall
Δ
Brick Expansion
0.28”
Wood Shrinkage
0.36”
Total Movement
0.64”
Total movement to be accounted
for: 0.64” = + 10/16” = + 5/8”

33. Example No.1 continued
Example of distress where differential movement between wood frame and brick
veneer was not accounted for

34. Example No.1 continued
Why did this happen?

35. Example No. 2
Brick Veneer with Cast-in-Place Concrete Backing
21-story cast-in-place concrete
structure with brick veneer
located in Baltimore, Maryland

36. + 4.2”
+ 1.5”
+ 5.7”
Shortening of Concrete Frame:
Expansion of Masonry:
Total Veneer Movement:
Example No. 2 continued

37. Example No. 2 continued
• 21 floors
• 5.7 in total movement = approximately
0.27” of movement per floor
• Therefore, shelf angels at each floor

38. Example No. 2 continued

39. Example No. 2 continued
• Shelf angles 3/8” thick and mortar
joints were 1/2” thick
• 35% compressible filler included in
joint below angle
• 3/4“ deep covering edge of angle lip
prevents any expansion joint between
brick coursing
• However, the Design Professional
allowed joints to be every other floor
during value engineering

40. Example No. 2 continued
Example of distress resulting from poorly designed expansion joint

41. Example No. 3
Concrete Masonry Veneer
• Designed: Circa 2005
• Built: Circa 2006
• Distress: Circa 2011

42. Example No. 3 continued
Example of distress at expansion joints at alternating floors and
welded flashing
• Joints at alternating floors
• Shelf angles are continuous
and welded
• Flashing is continuous and
welded

43. Example No. 3 continued
+183’-3”
Total Vertical Masonry Expansion:
+ 1.1 inches (CMU Veneer)
Formula:
Δm = H * ε t Δ T
ε t :Temperature Expansion: 4.50 x
10-6 in/in /°F (CMU Veneer)
Δ T: Temperature Change (110)
BIA: Maximum temperature of
wall 140
43

44. Example No. 3 continued
0.11
0.12
Total Concrete Frame Shortening
(Ultimate Life): + 4.3 inches.
0.14
0.15
0.17
0.18
0.19
0.21
0.21
0.22
0.24
0.24
0.25
0.26
0.26
0.24
0.25
0.24
0.25
Note:
1. Concrete shortening calculation based on
ACI 318-99, ACI 209 R-92 and ASCE 7-98.
2. Concrete shortening is affected by concrete
creep, shrinkage, and elastic shortening per
floor (inches).
3. Variations on concrete frame shortening
result from variations in column layout,
floor height, floor loading, and concrete
length.
4. Concrete material properties taken from
construction documents.
0.39
4.32
44

45. + 5.4”
Total Veneer Movement:
+ 1.1”
Expansion of Masonry:
Shortening of Concrete Frame:
+ 4.3”
Example No. 3 continued
Cumulative Calculated
Concrete & Masonry Veneer
Vertical Movement
(Ultimate Life)
Total Anticipated
Cumulative Concrete and
Masonry Movement During
the Ultimate Life of the
Structure: + 5.4 inches

46. Example No. 3 continued
Specifications
Section 04810 – Unit Masonry Assemblies
2.8 MISCELLANEOUS MASONRY ACCESSORIES
A. Compressible Filler: Premolded filler strips complying with ASTM D
1056, Grade 2A1; compressible up to 35 percent; of width and thickness
indicated; formulated from neoprene urethane or PVC.
3.9 CONTROL AND EXPANSION JOINTS
C. Provide horizontal , pressure relieving joints by either leaving an air
space or inserting a compressible filler of width required for
installing sealant and backer rod specified in Division 7 Section
“Joint Sealants,” but not less than 3/8 inch.
1. Locate horizontal, pressure-relieving joints beneath shelf angles
supporting masonry.
2. Compressible filler to be compressible to 35% of thickness.
TSG Note: Compressible filler only allows for 1/4” expansion of 3/8” joint
9

47. Example No. 3 continued
Expansion Joint Detail
(From Architectural Drawings)
• 3/8” (.375) vertical gap shown with sealant joint, backer rod, and
compressible filler.
• Expansion joints to be located at every other floor.
• Vertical movement for typical 18.16’ between expansion joints (7th and
8th floor) mid height of building 0.62 inch ~ 5/8” > 3/8”.
47

48. Example No. 3 continued
Section (From Structural Drawings)
Section (From Structural Drawings)
Typical Shelf Angle Detail Shown on Structural Drawings
•
•
•
•
No vertical expansion area shown between top of brick and bottom of angle.
Overhang of masonry from end of angle is not defined.
No gap is indicated between masonry and concrete floor slab.
L6 x 6 x 3/8 shelf angle supports 4” CMU.
8a

49. Example No. 3 continued
Construction Documents:
Ten (10) levels with shelf angles (Denoted
by Arrows).
-Total Allowable Vertical Expansion height
with 35% compressible fill: 2.44 inches.
-Total Allowable Vertical Expansion height
without compressible fill: 3.75 inches.
Total Anticipated Vertical Expansion:
+5.4 inches > Total Designed Vertical
Expansion (w/o compressible fill): 3.75
inches.
Total Anticipated Vertical Expansion:
+5.4 inches > Total Designed Vertical
Expansion (w/compressible filler): 2.44
inches.
49

50. Example No. 3 continued
0.10
0.12
0.13
0.14
0.16
0.17
0.19
0.20
0.20
0.21
0.23
0.23
0.24
0.25
0.25
0.22
0.23
0.23
0.24
Total Concrete Frame Shortening
(Over 5 years): + 4.1 inches.
Note:
1. Concrete shortening calculation based
on ACI 318-99, ACI 209 R-92 and ASCE 798.
2. Concrete shortening is affected by
concrete creep, shrinkage, and elastic
shortening per floor (inches).
3. Variations on concrete frame shortening
result from variations in column layout,
floor height, floor loading, and concrete
length.
4. Concrete material properties taken from
construction documents.
0.37
4.32
50

51. + 5.2”
+ 1.1”
+ 4.1”
Example No. 3 continued
Total Cumulative Concrete
and Masonry Movement
(Over 5 years): + 5.2 inches.
Total Veneer Movement:
Expansion of Masonry:
Shortening of Concrete Frame:
•
Remaining Concrete and
Masonry Movement Over
Life of Structure
- Ultimate Concrete
Shortening: + 4.3 inches
- Concrete Shortening to
Date: + 4.1 inches
• Remaining Concrete
Shortening : + 0.2 inches
• Masonry Expansion: + 1.1
inches
Total Remaining Concrete
and Masonry Movement
Over Life of Structure:
+ 1.3 inches

52. Caution in Use of Generic Details
BIA Technical Note 7 - Water Resistance of Brick Masonry Design and Detailing
Details Require Project Specific Coordination
11

53. Caution in Use of Generic Details continued
BIA Technical Note 28B - Brick Veneer
11

54. Caution in Use of Generic Details continued
Emphasis added by TSG
11

55. Attention to Detail
• Pay Attention to Construction Tolerances
Per ACI 117 “Structural Specifications for Tolerances for
Concrete Construction and Materials” the lateral
alignment for cast-in-place concrete members, including
elevated slabs, is permitted to vary up to 1” from a
specified line or point in the horizontal plane.
11

56. THANK YOU
for attending
Combined Effects of Multi-Story
Buildings and Brick Veneer
Presented By:
Michael A. Matthews, P.E.
The Structures Group, Inc.
Please remember to complete an evaluation
form. You may leave the form on the table
outside the room or with a room monitor.