clt floor design: strength, deflection and vibrations · presented on [date] by [author’s name]...
TRANSCRIPT
![Page 1: CLT Floor Design: Strength, Deflection and Vibrations · Presented on [Date] by [Author’s Name] (Edit the Master Slide to change this text) CLT Floor Design: Strength, Deflection](https://reader034.vdocuments.mx/reader034/viewer/2022042106/5e84abd042399d245909e2d9/html5/thumbnails/1.jpg)
Presented on [Date] by [Author’s Name]
(Edit the Master Slide to change this text)
CLT Floor Design:
Strength, Deflection and
Vibrations
Scott Breneman, PhD, PE, SE
Senior Technical Director
Architectural and Engineering Solutions
WoodWorks – Wood Products Council
Toward Taller Wood Buildings
November 2014
![Page 2: CLT Floor Design: Strength, Deflection and Vibrations · Presented on [Date] by [Author’s Name] (Edit the Master Slide to change this text) CLT Floor Design: Strength, Deflection](https://reader034.vdocuments.mx/reader034/viewer/2022042106/5e84abd042399d245909e2d9/html5/thumbnails/2.jpg)
Product Standardization
![Page 3: CLT Floor Design: Strength, Deflection and Vibrations · Presented on [Date] by [Author’s Name] (Edit the Master Slide to change this text) CLT Floor Design: Strength, Deflection](https://reader034.vdocuments.mx/reader034/viewer/2022042106/5e84abd042399d245909e2d9/html5/thumbnails/3.jpg)
CLT Composition
Planks in alternating directions
![Page 4: CLT Floor Design: Strength, Deflection and Vibrations · Presented on [Date] by [Author’s Name] (Edit the Master Slide to change this text) CLT Floor Design: Strength, Deflection](https://reader034.vdocuments.mx/reader034/viewer/2022042106/5e84abd042399d245909e2d9/html5/thumbnails/4.jpg)
CLT Composition
![Page 5: CLT Floor Design: Strength, Deflection and Vibrations · Presented on [Date] by [Author’s Name] (Edit the Master Slide to change this text) CLT Floor Design: Strength, Deflection](https://reader034.vdocuments.mx/reader034/viewer/2022042106/5e84abd042399d245909e2d9/html5/thumbnails/5.jpg)
CLT Product Standard
ANSI/APA PRG 320
• CLT Stress classes
• Quality Assurance testing
• Identification marking
![Page 6: CLT Floor Design: Strength, Deflection and Vibrations · Presented on [Date] by [Author’s Name] (Edit the Master Slide to change this text) CLT Floor Design: Strength, Deflection](https://reader034.vdocuments.mx/reader034/viewer/2022042106/5e84abd042399d245909e2d9/html5/thumbnails/6.jpg)
Product Reports
![Page 7: CLT Floor Design: Strength, Deflection and Vibrations · Presented on [Date] by [Author’s Name] (Edit the Master Slide to change this text) CLT Floor Design: Strength, Deflection](https://reader034.vdocuments.mx/reader034/viewer/2022042106/5e84abd042399d245909e2d9/html5/thumbnails/7.jpg)
Structural Composition of CLT
Laminations: (Per PRG 320-2012)
5/8” to 2” thick.
Machine Stress Rated or Visually Graded Dimensional Lumber or SCL
Dried to 12% Moisture Content before layup.
A common NA thickness is 1 3/8” (planed 2x stock)
PRG 320 provides thickness to width requirements of laminations
![Page 8: CLT Floor Design: Strength, Deflection and Vibrations · Presented on [Date] by [Author’s Name] (Edit the Master Slide to change this text) CLT Floor Design: Strength, Deflection](https://reader034.vdocuments.mx/reader034/viewer/2022042106/5e84abd042399d245909e2d9/html5/thumbnails/8.jpg)
Structural Composition of CLT
Layers: (Per PRG 320-2012)
Oriented in orthogonal arrangement
Odd number of symmetric layers most common
Double parallel exterior layers permitted
Unbalanced layup permitted
Reference glu-lam adhesive standard (AITC 405)
![Page 9: CLT Floor Design: Strength, Deflection and Vibrations · Presented on [Date] by [Author’s Name] (Edit the Master Slide to change this text) CLT Floor Design: Strength, Deflection](https://reader034.vdocuments.mx/reader034/viewer/2022042106/5e84abd042399d245909e2d9/html5/thumbnails/9.jpg)
Structural Composition of CLT
Panels, also known as Billets.
20 inch max thickness in PRG 320
Up to 8 ft or more wide per manufacturer and shipping
Up to 40 ft or more long per manufacturer and shipping
Major axis: stronger, stiffer, usually long direction
Minor axis: less strong and stiff, usually short direction
![Page 10: CLT Floor Design: Strength, Deflection and Vibrations · Presented on [Date] by [Author’s Name] (Edit the Master Slide to change this text) CLT Floor Design: Strength, Deflection](https://reader034.vdocuments.mx/reader034/viewer/2022042106/5e84abd042399d245909e2d9/html5/thumbnails/10.jpg)
CLT Stress Grades
Stress Grade Major Strength
Direction
Minor Strength Direction
E1 1950f-1.7E MSR SPF #3 Spruce Pine Fir
E2 1650f-1.5E MSR DFL #3 Doug Fir Larch
E3 1200f-1.2E MSR Misc #3 Misc
E4 1950f-1.7E MSR SP #3 Southern Pine
V1 #2 Doug Fir Larch #3 Doug Fir Larch
V2 #1/#2 Spruce Pine Fir #3 Spruce Pine Fir
V3 #2 Southern Pine #3 Southern Pine
Non-mandatory in PRG 320. Other stress grades including SCL permitted
![Page 11: CLT Floor Design: Strength, Deflection and Vibrations · Presented on [Date] by [Author’s Name] (Edit the Master Slide to change this text) CLT Floor Design: Strength, Deflection](https://reader034.vdocuments.mx/reader034/viewer/2022042106/5e84abd042399d245909e2d9/html5/thumbnails/11.jpg)
PRG 320 Defined Layups
![Page 12: CLT Floor Design: Strength, Deflection and Vibrations · Presented on [Date] by [Author’s Name] (Edit the Master Slide to change this text) CLT Floor Design: Strength, Deflection](https://reader034.vdocuments.mx/reader034/viewer/2022042106/5e84abd042399d245909e2d9/html5/thumbnails/12.jpg)
Examples of CLT Configurations
3-ply 3-layer
5-ply 5-layer
6-ply 5-layer
9-ply 9-layer
5-ply 3-layer
7-ply 5-layer
8-ply 5-layer
9-ply 7-layer
![Page 13: CLT Floor Design: Strength, Deflection and Vibrations · Presented on [Date] by [Author’s Name] (Edit the Master Slide to change this text) CLT Floor Design: Strength, Deflection](https://reader034.vdocuments.mx/reader034/viewer/2022042106/5e84abd042399d245909e2d9/html5/thumbnails/13.jpg)
Strength
Photos Courtesy Structurlam
![Page 14: CLT Floor Design: Strength, Deflection and Vibrations · Presented on [Date] by [Author’s Name] (Edit the Master Slide to change this text) CLT Floor Design: Strength, Deflection](https://reader034.vdocuments.mx/reader034/viewer/2022042106/5e84abd042399d245909e2d9/html5/thumbnails/14.jpg)
Floors
![Page 15: CLT Floor Design: Strength, Deflection and Vibrations · Presented on [Date] by [Author’s Name] (Edit the Master Slide to change this text) CLT Floor Design: Strength, Deflection](https://reader034.vdocuments.mx/reader034/viewer/2022042106/5e84abd042399d245909e2d9/html5/thumbnails/15.jpg)
Non-homogenous, anisotropic material
Structural Section Properties
![Page 16: CLT Floor Design: Strength, Deflection and Vibrations · Presented on [Date] by [Author’s Name] (Edit the Master Slide to change this text) CLT Floor Design: Strength, Deflection](https://reader034.vdocuments.mx/reader034/viewer/2022042106/5e84abd042399d245909e2d9/html5/thumbnails/16.jpg)
Design Properties based on Extreme Fiber Model:
Flexural Capacity Check:
Mb ≤ (FbSeff)′
Mb = applied bending moment
(FbSeff)′ = adjusted bending capacity
Seff = effective section modulus
Fb = reference bending design value of outer lamination
Flexural Strength
Mb
Bending Stress
Reference: NDS 2015 & US CLT Handbook
![Page 17: CLT Floor Design: Strength, Deflection and Vibrations · Presented on [Date] by [Author’s Name] (Edit the Master Slide to change this text) CLT Floor Design: Strength, Deflection](https://reader034.vdocuments.mx/reader034/viewer/2022042106/5e84abd042399d245909e2d9/html5/thumbnails/17.jpg)
Design Properties based on Extreme Fiber Model:
Flexural Capacity Check (ASD)
(FbSeff)′ = CD CM Ct CL (FbSeff)
Flexural Strength
Mb
Bending Stress
Commonly
1.0From Manufacturer*
Mb ≤ CD (1.0) (FbSeff)
per
NDS
Reference: NDS 2015 & US CLT Handbook
![Page 18: CLT Floor Design: Strength, Deflection and Vibrations · Presented on [Date] by [Author’s Name] (Edit the Master Slide to change this text) CLT Floor Design: Strength, Deflection](https://reader034.vdocuments.mx/reader034/viewer/2022042106/5e84abd042399d245909e2d9/html5/thumbnails/18.jpg)
Design Properties based on Extreme Fiber Model:
Flexural Capacity Check (LRFD)
(FbSeff)′ = CM Ct CL (FbSeff) Kf ϕ λ
Flexural Strength
Mb
Bending Stress
Commonly
1.0From Manufacturer
Mb ≤ (1.0) (FbSeff) (2.54)(0.85) λ
per
NDS 2015
& CLT
Handbook
Reference: NDS 2015 & US CLT Handbook
![Page 19: CLT Floor Design: Strength, Deflection and Vibrations · Presented on [Date] by [Author’s Name] (Edit the Master Slide to change this text) CLT Floor Design: Strength, Deflection](https://reader034.vdocuments.mx/reader034/viewer/2022042106/5e84abd042399d245909e2d9/html5/thumbnails/19.jpg)
Select acceptable CLT section
Given:
16 foot span floor
40 psf live load, 40 psf total dead load.
Assume:
one-way spanning action in major axis of CLT
ASD Dead + Live Flexural Demands:
Mb = w L2 / 8 = (40+40psf) (16ft)2 / 8 = 2560 lb-ft/ft
Design Example: Flexure
16 foot span
![Page 20: CLT Floor Design: Strength, Deflection and Vibrations · Presented on [Date] by [Author’s Name] (Edit the Master Slide to change this text) CLT Floor Design: Strength, Deflection](https://reader034.vdocuments.mx/reader034/viewer/2022042106/5e84abd042399d245909e2d9/html5/thumbnails/20.jpg)
Try 5 ply, (6 7/8 in thick) CLT Grade V2 Section
Design Example: Flexure
Reference: ANSI/APA PRG 320-2012
![Page 21: CLT Floor Design: Strength, Deflection and Vibrations · Presented on [Date] by [Author’s Name] (Edit the Master Slide to change this text) CLT Floor Design: Strength, Deflection](https://reader034.vdocuments.mx/reader034/viewer/2022042106/5e84abd042399d245909e2d9/html5/thumbnails/21.jpg)
ASD Flexural Capacity:
Dead + Live load, CD = 1.0
(FbSeff)′ = CD (1.0) (Fb Seff)
= 1.0 (1.0) (4675 lb-ft/ft)
= 4675 lb-ft/ft
Mb = 2560 lb-ft/ft ≤ F’b Seff = 4675 lb-ft/ft
Flexural Strength OK
Design Example: Flexure
16 foot span
![Page 22: CLT Floor Design: Strength, Deflection and Vibrations · Presented on [Date] by [Author’s Name] (Edit the Master Slide to change this text) CLT Floor Design: Strength, Deflection](https://reader034.vdocuments.mx/reader034/viewer/2022042106/5e84abd042399d245909e2d9/html5/thumbnails/22.jpg)
Design Properties based on Extreme Fiber Model:
Shear Capacity Check:
Vplanar ≤ Fs(Ib/Q)eff′
Vplanar = applied shear
Fs (IbQeff) ′ = adjusted shear strength
Shear Strength
Vplanar
Shear Stress
Reference: NDS 2015 & US CLT Handbook
![Page 23: CLT Floor Design: Strength, Deflection and Vibrations · Presented on [Date] by [Author’s Name] (Edit the Master Slide to change this text) CLT Floor Design: Strength, Deflection](https://reader034.vdocuments.mx/reader034/viewer/2022042106/5e84abd042399d245909e2d9/html5/thumbnails/23.jpg)
Design Properties based on Extreme Fiber Model:
Shear Capacity Check (ASD):
Fs(IbQ)eff′ = CM Ct (Fs(IbQ)eff) = CM Ct Vs
Vplanar ≤ (1.0) Vs
Shear Strength
Vplanar
Shear Stress
Commonly
1.0From Manufacturer for
Standard Sections
Reference: NDS 2015 & US CLT Handbook
![Page 24: CLT Floor Design: Strength, Deflection and Vibrations · Presented on [Date] by [Author’s Name] (Edit the Master Slide to change this text) CLT Floor Design: Strength, Deflection](https://reader034.vdocuments.mx/reader034/viewer/2022042106/5e84abd042399d245909e2d9/html5/thumbnails/24.jpg)
Stiffness & Deflection
Major Axis Stiffness
EIeff,0 GAeff,0
Minor Axis Stiffness
EIeff,90 GAeff,90
![Page 25: CLT Floor Design: Strength, Deflection and Vibrations · Presented on [Date] by [Author’s Name] (Edit the Master Slide to change this text) CLT Floor Design: Strength, Deflection](https://reader034.vdocuments.mx/reader034/viewer/2022042106/5e84abd042399d245909e2d9/html5/thumbnails/25.jpg)
Structural Material Assumptions
Assumptions Used in CLT Handbook and ANSI/APA
PRG 320-2012 to develop section properties.
Given lumber for a lamination with modulus of elasticity
for bending in major strength direction, E0, assume:
• E90 = E0 / 30
• G0 = E0 /16
• G90 = G0 / 10 = E0 / 160
Reference: US CLT Handbook & PRG 320
![Page 26: CLT Floor Design: Strength, Deflection and Vibrations · Presented on [Date] by [Author’s Name] (Edit the Master Slide to change this text) CLT Floor Design: Strength, Deflection](https://reader034.vdocuments.mx/reader034/viewer/2022042106/5e84abd042399d245909e2d9/html5/thumbnails/26.jpg)
Flexural Stiffness
Bending Stress
EIeff
Shear Analogy Method
Reference: US CLT Handbook Chapter 3
![Page 27: CLT Floor Design: Strength, Deflection and Vibrations · Presented on [Date] by [Author’s Name] (Edit the Master Slide to change this text) CLT Floor Design: Strength, Deflection](https://reader034.vdocuments.mx/reader034/viewer/2022042106/5e84abd042399d245909e2d9/html5/thumbnails/27.jpg)
Shear Stiffness
GAeff
Reference: US CLT Handbook Chapter 3
Shear Analogy Method
![Page 28: CLT Floor Design: Strength, Deflection and Vibrations · Presented on [Date] by [Author’s Name] (Edit the Master Slide to change this text) CLT Floor Design: Strength, Deflection](https://reader034.vdocuments.mx/reader034/viewer/2022042106/5e84abd042399d245909e2d9/html5/thumbnails/28.jpg)
Flexural Stiffness
EIeff
GAeff
Important to develop properties of
new CLT Sections.
Not to use standard CLT Sections
![Page 29: CLT Floor Design: Strength, Deflection and Vibrations · Presented on [Date] by [Author’s Name] (Edit the Master Slide to change this text) CLT Floor Design: Strength, Deflection](https://reader034.vdocuments.mx/reader034/viewer/2022042106/5e84abd042399d245909e2d9/html5/thumbnails/29.jpg)
Structural Section Properties
Values in RED provided by CLT manufacturer
Flexural Strength: FbSeff,0
Flexural Stiffness: EIeff,0
Shear Strength: Vs,0
Shear Stiffness: GAeff,0
FbSeff,90
EIeff,90
Vs,90
GAeff,90
Reference: PRG 320 and CLT Product Reports
![Page 30: CLT Floor Design: Strength, Deflection and Vibrations · Presented on [Date] by [Author’s Name] (Edit the Master Slide to change this text) CLT Floor Design: Strength, Deflection](https://reader034.vdocuments.mx/reader034/viewer/2022042106/5e84abd042399d245909e2d9/html5/thumbnails/30.jpg)
General Purpose, 2 Way, Plate Action
Flexural Stiffness
EIeff,0 EIeff,90
Shear Stiffness:
5/6 GAeff,0 5/6 GAeff,90
5/6 from A′ = 5/6 A for rectangular sections
Deflection Calculations
![Page 31: CLT Floor Design: Strength, Deflection and Vibrations · Presented on [Date] by [Author’s Name] (Edit the Master Slide to change this text) CLT Floor Design: Strength, Deflection](https://reader034.vdocuments.mx/reader034/viewer/2022042106/5e84abd042399d245909e2d9/html5/thumbnails/31.jpg)
General Purpose: 1 Way, Beam Action
Stiffness: EIeff,0 5/6 GAeff,0
Deflection Calculations
Can model multiple spans, cantilevers, etc.
![Page 32: CLT Floor Design: Strength, Deflection and Vibrations · Presented on [Date] by [Author’s Name] (Edit the Master Slide to change this text) CLT Floor Design: Strength, Deflection](https://reader034.vdocuments.mx/reader034/viewer/2022042106/5e84abd042399d245909e2d9/html5/thumbnails/32.jpg)
Example Calculation:
Uniform loading on one way slab:
Beam Analysis using
Flexural Stiffness: EIeff,0
Shear Stiffness: 5/6 GAeff,0
Maximum Deflection @ Mid-Span
Example Deflection Calculations
16 foot span
5/6 GAeff
Design Example:
= 0.161 in + 0.02 in = 0.183 in
= L / 1050
w = 80 psf
![Page 33: CLT Floor Design: Strength, Deflection and Vibrations · Presented on [Date] by [Author’s Name] (Edit the Master Slide to change this text) CLT Floor Design: Strength, Deflection](https://reader034.vdocuments.mx/reader034/viewer/2022042106/5e84abd042399d245909e2d9/html5/thumbnails/33.jpg)
Simplified Beam Deflections:
Given load pattern and support conditions:
Deflection Calculations
Span, L5/6 GAeff
Uniform load, w
Find Apparent Flexural Stiffness, EIapp, such that
EIapp
�����=�����
1 +11.5����� ������Reference: US CLT Handbook
![Page 34: CLT Floor Design: Strength, Deflection and Vibrations · Presented on [Date] by [Author’s Name] (Edit the Master Slide to change this text) CLT Floor Design: Strength, Deflection](https://reader034.vdocuments.mx/reader034/viewer/2022042106/5e84abd042399d245909e2d9/html5/thumbnails/34.jpg)
Simplified Beam Deflections
For single span, simple loading patterns, Apparent Flexural
Stiffness, EIapp, to determine maximum (mid-span) deflection:
Deflection Calculations
US CLT Handbook
�����=�����
1 +16�����������������=
�����1 + ������� ������
NDS 2015
����= ����� �������= ���� �⁄ � = �� 16⁄
For Major Axis Spans:
Reference: US CLT Handbook & NDS 2015
![Page 35: CLT Floor Design: Strength, Deflection and Vibrations · Presented on [Date] by [Author’s Name] (Edit the Master Slide to change this text) CLT Floor Design: Strength, Deflection](https://reader034.vdocuments.mx/reader034/viewer/2022042106/5e84abd042399d245909e2d9/html5/thumbnails/35.jpg)
Simplified Beam Deflections
For single span, simple loading patterns, Apparent Flexural
Stiffness, EIapp, to determine maximum (mid-span) deflection:
Deflection Calculations
�����=�����
1 +16�����������������=
�����1 + ������� ������
Loading End Supports Ks
Uniform Pinned 11.5
Fixed 57.6
Midspan Line Pinned 14.4
Fixed 57.6
Apparent Flexural Stiffness depends on Load Pattern and Support Conditions
![Page 36: CLT Floor Design: Strength, Deflection and Vibrations · Presented on [Date] by [Author’s Name] (Edit the Master Slide to change this text) CLT Floor Design: Strength, Deflection](https://reader034.vdocuments.mx/reader034/viewer/2022042106/5e84abd042399d245909e2d9/html5/thumbnails/36.jpg)
Simplified Beam Deflections
For single span, simple loading patterns, Apparent Flexural
Stiffness, EIapp, to determine maximum (mid-span) deflection:
Deflection Calculations
�����=�����
1 +16�����������������=
�����1 + ������� ������
Apparent Flexural Stiffness depends on Span Length
L1 = 20 foot
������≠ ������L2 = 16 foot
![Page 37: CLT Floor Design: Strength, Deflection and Vibrations · Presented on [Date] by [Author’s Name] (Edit the Master Slide to change this text) CLT Floor Design: Strength, Deflection](https://reader034.vdocuments.mx/reader034/viewer/2022042106/5e84abd042399d245909e2d9/html5/thumbnails/37.jpg)
Deformation to Long Term Loads
Creep Factor
� = ����� + �� NDS Eq 3.5-1
�������
Deflection due to short-term loading
Immediate deflection due to long term loading
2.0 for CLT in dry service conditions
Reference: US CLT Handbook & NDS 2015
![Page 38: CLT Floor Design: Strength, Deflection and Vibrations · Presented on [Date] by [Author’s Name] (Edit the Master Slide to change this text) CLT Floor Design: Strength, Deflection](https://reader034.vdocuments.mx/reader034/viewer/2022042106/5e84abd042399d245909e2d9/html5/thumbnails/38.jpg)
Occupant perception of vibration is a highly recommended design
consideration.
One approach: CLT Handbook, Chapter 7
Calculated natural frequency of simple span:
� = 2.1882��
�����"�
Where:
EIapp = apparent stiffness for 1 foot strip, pinned supported, uniformly
loaded, simple span (Ks = 11.5) (lb-in2)
rrrr = specific gravity of the CLT
A = the cross section area (thickness x 12 inches) (in2)
Floor Vibration
Reference: US CLT Handbook, Chapter 7
![Page 39: CLT Floor Design: Strength, Deflection and Vibrations · Presented on [Date] by [Author’s Name] (Edit the Master Slide to change this text) CLT Floor Design: Strength, Deflection](https://reader034.vdocuments.mx/reader034/viewer/2022042106/5e84abd042399d245909e2d9/html5/thumbnails/39.jpg)
CLT Handbook, Chapter 7 recommends,
Floor Vibration
Max span L
� = 2.1882��
�����"� ≥ 9.0&'
and
Reference: US CLT Handbook, Chapter 7
![Page 40: CLT Floor Design: Strength, Deflection and Vibrations · Presented on [Date] by [Author’s Name] (Edit the Master Slide to change this text) CLT Floor Design: Strength, Deflection](https://reader034.vdocuments.mx/reader034/viewer/2022042106/5e84abd042399d245909e2d9/html5/thumbnails/40.jpg)
CLT Handbook, Chapter 7 Recommendations
Floor Vibration
Research by Lin Hu, et al. at
Experimental Verification – Results
0.04
0.03
0.02
0.01
0
0.05
0.06
0.07
0 5 10 15
Fundamental Natural Frequency (Hz)
20
Sta
tic D
efl
ecti
on
(in
ch
)
Criterion ( f/d^0.7>125.1)
Unacceptable
Marginal
Acceptable
![Page 41: CLT Floor Design: Strength, Deflection and Vibrations · Presented on [Date] by [Author’s Name] (Edit the Master Slide to change this text) CLT Floor Design: Strength, Deflection](https://reader034.vdocuments.mx/reader034/viewer/2022042106/5e84abd042399d245909e2d9/html5/thumbnails/41.jpg)
CLT Handbook, Chapter 7 method:
Natural frequencies above 9 Hz and:
EIapp depends on L, so an iterative calculation required.
Only depends on CLT section properties, soS
Values calculated and provided by CLT Manufactures
16ft span example: V2 Grade 5 ply (6 7/8 in) L max = 16.7 feet.
Floor Vibration
Max span L
Reference: US CLT Handbook, Chapter 7
![Page 42: CLT Floor Design: Strength, Deflection and Vibrations · Presented on [Date] by [Author’s Name] (Edit the Master Slide to change this text) CLT Floor Design: Strength, Deflection](https://reader034.vdocuments.mx/reader034/viewer/2022042106/5e84abd042399d245909e2d9/html5/thumbnails/42.jpg)
CLT Handbook, Chapter 7 Recommendations
Floor Vibration
Continuous multi-span floor
� L2 is the longest span
� Use the design method to determine L2
assuming it is a single span floor
![Page 43: CLT Floor Design: Strength, Deflection and Vibrations · Presented on [Date] by [Author’s Name] (Edit the Master Slide to change this text) CLT Floor Design: Strength, Deflection](https://reader034.vdocuments.mx/reader034/viewer/2022042106/5e84abd042399d245909e2d9/html5/thumbnails/43.jpg)
CLT Handbook, Chapter 7 Recommendations
Floor Vibration
With Suspended Ceiling
Use the design method without
including the mass and stiffness
of the drywall
![Page 44: CLT Floor Design: Strength, Deflection and Vibrations · Presented on [Date] by [Author’s Name] (Edit the Master Slide to change this text) CLT Floor Design: Strength, Deflection](https://reader034.vdocuments.mx/reader034/viewer/2022042106/5e84abd042399d245909e2d9/html5/thumbnails/44.jpg)
CLT Handbook, Chapter 7 Recommendations
Floor Vibration
With lightweight topping (<20 Ib./ft.2) and drywall
� Lightweight topping examples:
- Wood panel
- Gypsum board
- Cement fibreboard
� Use proposed design
method without including
the mass and stiffness of
the drywall and the topping
![Page 45: CLT Floor Design: Strength, Deflection and Vibrations · Presented on [Date] by [Author’s Name] (Edit the Master Slide to change this text) CLT Floor Design: Strength, Deflection](https://reader034.vdocuments.mx/reader034/viewer/2022042106/5e84abd042399d245909e2d9/html5/thumbnails/45.jpg)
CLT Handbook, Chapter 7 Recommendations
Floor Vibration
With heavy topping ( >20 Ib./ft.2)
Preliminary Recommendations
• Use the design method
without including the mass
and stiffness of the heavy
topping to determine the
span
• Reduce the bare floor
stiffness and mass by
10%
![Page 46: CLT Floor Design: Strength, Deflection and Vibrations · Presented on [Date] by [Author’s Name] (Edit the Master Slide to change this text) CLT Floor Design: Strength, Deflection](https://reader034.vdocuments.mx/reader034/viewer/2022042106/5e84abd042399d245909e2d9/html5/thumbnails/46.jpg)
Occupant perception of vibration a recommended design consideration
CLT Handbook, Chapter 7 recommends natural frequencies above 9 Hz
and:
Limitations:
• Potential advantages of topping slab stiffness not taken into account
• Potential advantages of multiple spans or other restraining details
• Long spans can be uneconomical to keep natural frequency above 9 Hz.
Floor Vibration
Max span L
![Page 47: CLT Floor Design: Strength, Deflection and Vibrations · Presented on [Date] by [Author’s Name] (Edit the Master Slide to change this text) CLT Floor Design: Strength, Deflection](https://reader034.vdocuments.mx/reader034/viewer/2022042106/5e84abd042399d245909e2d9/html5/thumbnails/47.jpg)
SOM Timber Tower
Source: SOM Timber Tower Research Project, May 2013
Prototype Building
![Page 48: CLT Floor Design: Strength, Deflection and Vibrations · Presented on [Date] by [Author’s Name] (Edit the Master Slide to change this text) CLT Floor Design: Strength, Deflection](https://reader034.vdocuments.mx/reader034/viewer/2022042106/5e84abd042399d245909e2d9/html5/thumbnails/48.jpg)
SOM Timber Tower
24 to 25 ft CLT
Floor Spans.
6.5 to 8.5 Hz Range
![Page 49: CLT Floor Design: Strength, Deflection and Vibrations · Presented on [Date] by [Author’s Name] (Edit the Master Slide to change this text) CLT Floor Design: Strength, Deflection](https://reader034.vdocuments.mx/reader034/viewer/2022042106/5e84abd042399d245909e2d9/html5/thumbnails/49.jpg)
Long spans can be designed using CLT Handbook Criteria:
Keep Fundamental Frequency > 9 hz
Idealized as Single Span, Simply Supported Panels
24 foot spans result in ~12 inch thick or greater CLT floors.
Alternative Vibration Criteria
![Page 50: CLT Floor Design: Strength, Deflection and Vibrations · Presented on [Date] by [Author’s Name] (Edit the Master Slide to change this text) CLT Floor Design: Strength, Deflection](https://reader034.vdocuments.mx/reader034/viewer/2022042106/5e84abd042399d245909e2d9/html5/thumbnails/50.jpg)
SOM Timber Tower
CIP R.C. Beam
Precast R.C. Beam
CLT Floor Panel
Steel dowels
Exterior Spandrel Beam
Rigid Panel to
Spandrel
Connection
![Page 51: CLT Floor Design: Strength, Deflection and Vibrations · Presented on [Date] by [Author’s Name] (Edit the Master Slide to change this text) CLT Floor Design: Strength, Deflection](https://reader034.vdocuments.mx/reader034/viewer/2022042106/5e84abd042399d245909e2d9/html5/thumbnails/51.jpg)
Alternative: Use acceptance criteria which address low
frequency floors and alternative support configurations.
Calibration of dynamic modeling
with physical testing valuable
Alternative Vibration Criteria
![Page 52: CLT Floor Design: Strength, Deflection and Vibrations · Presented on [Date] by [Author’s Name] (Edit the Master Slide to change this text) CLT Floor Design: Strength, Deflection](https://reader034.vdocuments.mx/reader034/viewer/2022042106/5e84abd042399d245909e2d9/html5/thumbnails/52.jpg)
SOM Timber Tower used:
AISC Design Guide 11, Velocity Criteria (Chapter 6)
Acceptance Criteria selected:
≤ 16,000 µ-in/sec w/ moderate walking in living areas
≤ 8,000 µ-in/sec w/ slow walking pace in sleeping areas.
AISC DG 11 suggests approximate velocity limit of human perception
8,000 µ-in/sec at 8 Hz and above.
AISC Design Guide 11 not for dynamic modeling of CLT floors
Alternative Vibration Criteria
SOM Timber Tower Resulted in 8” Thick Floor
![Page 53: CLT Floor Design: Strength, Deflection and Vibrations · Presented on [Date] by [Author’s Name] (Edit the Master Slide to change this text) CLT Floor Design: Strength, Deflection](https://reader034.vdocuments.mx/reader034/viewer/2022042106/5e84abd042399d245909e2d9/html5/thumbnails/53.jpg)
Floor Panel to Floor Panel
Connection Styles
Interior Spline
Single Surface Spline
Double Surface Spline
Half Lap
![Page 54: CLT Floor Design: Strength, Deflection and Vibrations · Presented on [Date] by [Author’s Name] (Edit the Master Slide to change this text) CLT Floor Design: Strength, Deflection](https://reader034.vdocuments.mx/reader034/viewer/2022042106/5e84abd042399d245909e2d9/html5/thumbnails/54.jpg)
Floor Panel to Wall
Connection Styles
Platform Frame
With Only Screws
Platform Frame with
Double Brackets
Platform Frame with
Single Brackets
![Page 55: CLT Floor Design: Strength, Deflection and Vibrations · Presented on [Date] by [Author’s Name] (Edit the Master Slide to change this text) CLT Floor Design: Strength, Deflection](https://reader034.vdocuments.mx/reader034/viewer/2022042106/5e84abd042399d245909e2d9/html5/thumbnails/55.jpg)
Floor Panel to Wall
Connection Styles
Balloon Frame
With Supporting
Ledger
Platform Frame with
Hidden Bracket
Platform Frame with
Bracket
![Page 56: CLT Floor Design: Strength, Deflection and Vibrations · Presented on [Date] by [Author’s Name] (Edit the Master Slide to change this text) CLT Floor Design: Strength, Deflection](https://reader034.vdocuments.mx/reader034/viewer/2022042106/5e84abd042399d245909e2d9/html5/thumbnails/56.jpg)
US CLT Handbook
1. Introduction
2. Manufacturing
3. Structural
4. Lateral
5. Connections
6. DOL and Creep
7. Vibration
8. Fire
9. Sound
10.Enclosure
11.Environmental
12.Lifting
www.masstimber.com
![Page 57: CLT Floor Design: Strength, Deflection and Vibrations · Presented on [Date] by [Author’s Name] (Edit the Master Slide to change this text) CLT Floor Design: Strength, Deflection](https://reader034.vdocuments.mx/reader034/viewer/2022042106/5e84abd042399d245909e2d9/html5/thumbnails/57.jpg)
Presented on [Date] by [Author’s Name]
(Edit the Master Slide to change this text)
CLT Floor Design:
Strength, Deflection and
Vibrations
Scott Breneman, PhD, PE, SE
![Page 58: CLT Floor Design: Strength, Deflection and Vibrations · Presented on [Date] by [Author’s Name] (Edit the Master Slide to change this text) CLT Floor Design: Strength, Deflection](https://reader034.vdocuments.mx/reader034/viewer/2022042106/5e84abd042399d245909e2d9/html5/thumbnails/58.jpg)
Scott Breneman, PhD, PE, SE
Project Assistance also available
Questions?