Generalization of Structural Insulated Panels Test...
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Generalization of SIP Data Generalization of Structural Insulated Panels Test Data Eric Tompos, P.E., S.E., C.B.O. [email protected]
Transcript of Generalization of Structural Insulated Panels Test...
Generalization of SIP Data
Generalization of Structural Insulated Panels
Test Data
Eric Tompos, P.E., S.E., [email protected]
Generalization of SIP Data
Laboratory Testing—Idealized
Actual Construction—Generalized
Generalization of SIP Data
The Problem Adapt Test Data to Actual Conditions Apply short-duration test data to long-term loads Generalized loading conditions Generalized support conditions
Generalization of SIP Data
The Solution Engineered Design Identify design limits states Develop engineering properties based on
engineering mechanics Testing serves to validate predicted behavior
Generalization of SIP Data
The SolutionKey Limit StatesFlexural Stiffness Creep EffectsShear StrengthAxial Strength
Other limit states exist—consult design guide
Generalization of SIP Data
Flexural StiffnessSimply supported deflection equation including shear under uniform loads:
0
2
4
6
8
10
12
0 500 1000 1500 2000 2500 3000
1/Ks x106
1/E
a x 1
06
Generalization of SIP Data
Flexural Stiffness
OSB Strong-Axis
OSB Weak-Axis
Slope, 1/G
Y-Intercept, 1/Eb
Generalization of SIP Data
Flexural Stiffness
0%
2%
4%
6%
8%
10%
12%
10 12 14 16 18 20 22 24
Bending Stiffness (psi)
Freq
uenc
y of
Occ
uran
ce (%
)
Generalization of SIP Data
Flexural CreepCreep effects incorporated in manner similar to that used for wood and concreteTotal deflection considering creep (NDS):
Need value for creep coefficient, Kcr
Deflection due to sustained loads
Deflection due to transient loads
Total deflection for code check
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
0 100 200 300 400 500 600 700
Duration of Load (months)
Fact
iona
l Def
lect
ion,
Kcr
Generalization of SIP Data
Flexural Creep
EPS, XPS
Urethane
Taylor, S.B., Manbeck, H. B., Janowiak, J. J., Hiltunum, D.R. “Modeling Structural Insulated Panel (SIP) Flexural Creep Deflection.” J. Structural Engineering, Vol. 123, No. 12, December, 1997.
Generalization of SIP Data
Flexural Creep
Material Creep Coefficient, Kcr
EPS, XPS Core SIP 4.0
Urethane Core SIP 7.0
Seasoned Lumber 1.5
OSB or Wet Lumber 2.0
Reinforced Concrete 2.0
Generalization of SIP Data
Flexural CreepCreep Deflection Equation for SIPs
Consider Kcr based on load typeLoad Type (ASCE 7)
Creep Coefficient, Kcr
EPS/XPS UrethaneD, F, H, T 4.0 7.0
L 3.0 5.0E, W, S, R, Lr, Fa 1.0 1.0
Generalization of SIP Data
Flexural CreepCreep Rupture (Long-Term Strength) Same creep model applies Inverse of Kcr may be applied to reduce strength Creep rupture study has not been conducted to
validate model
Generalization of SIP Data
Transverse ShearFactors affecting core shear strengthCore type (EPS, XPS, urethane)Foam density and thicknessAdditives (flame retardant, insecticide)End support conditions
Shear Equation:
Generalization of SIP Data
Transverse Shear
0
24
6
810
12
14
1618
20
2 4 6 8 10 12 14
Overall Thickness, h (in.)
She
ar S
treng
th, F
v (p
si)
Generalization of SIP Data
Transverse ShearDepth correction factor requiredProcedure from ASTM D198
Additional adjustment factors required (e.g. support method)
Engineered Design of SIP Panels
Transverse Shear
Bearing Support
Spline Support
Generalization of SIP Data
Transverse Shear
Generalization of SIP Data
Axial StrengthAxial Strength (Secant Formula):
Engineered Design of SIP Panels
Axial Strength Model
0
500
1000
1500
2000
2500
3000
3500
0 20 40 60 80
Slenderness Ratio, L/r
Axi
al S
treng
th (l
bf)
Euler Buckling
Strength
Engineered Design of SIP Panels
Summary SIP panels behave in manner consistent with
engineering mechanics Using data to establish and validate
engineering mechanics permits rigourous design of SIPs for general loading and support conditions
Currently NTA SIP Design Guide provides detailed design methodology based on properties found in SIPA code report:
www.sips.org
