TECH BULLETIN. SIP No. Subject: Engineering Properties. Date: March 2011 (Revised January 2015)

Transcription

1 TECH BULLETIN SI No. 075 Subjet: Engineering roperties Date: Marh 011 (Reised January 015) R-Control SI hae been long reognized as a strutural omponent for use a wall, roof, or floor panels that resist strutural loads. The strutural apaity of R-Control SIs has been determined through extensie testing with leading independent third party aredited test laboratories. The results of these tests hae long been published in R-Control SI Load Design Charts and reognized in ICC ES ESR-33. The omplete pakage of strutural information that supports R-Control Load Design Chart #1 has been analyzed and reiewed in order to proide basi SI Engineering roperties for R-Control SIs. These R-Control SI Engineering roperties are suitable for use with NTA IM 14 TI 01, Engineered Design of SI anels using NTA Listing Report Data. A opy of NTA IM 14 TI 01 is attahed to this bulletin for referenes. R-Control SI Engineering roperties 1, roperty Allowable Tensile Stress, Ft (psi) 495 Allowable Compressie Stress, F (psi) 619 Elasti Modulus (Bending), Eb (psi) Shear Modulus, G (psi) 67 Allowable Core Shear Stress, F (psi) 4.5 Referene Depth, ho (in.) 4.5 Shear Depth Fator Exponent, m 0.85 Core Compressie Modulus, E (psi) 400 Faing Flexural Stiffness, Eflf (lbf-in. ) Core Compressie Strength, F (psi) 13.1 Core Dispersion Fator, k All properties are based on a minimum panel width of 4-inhes. Refer to NTA IM14 TI 01 SI Design Guide for details on engineered design using basi properties. h (in.) R-Control SI Setion roperties (in.) A V (in. /ft) A F (in. /ft) I (in. 4 /ft) R-Control SIs are made exlusiely with Foam-Control ES. R-Control SIs and Foam-Control ES are manufatured by AFM Corporation liensees. Copyright 015 AFM Corporation. All rights resered. rinted in USA. R-Control, Foam-Control, erform Guard, and Control, Not Compromise are registered trademarks of AFM Corporation, Lakeille, MN. CONTROL, NOT COMROMISE.

2 ENGINEERED DESIGN OF SI ANELS USING NTA LISTING REORT DATA 1. SCOE 1.1. GENERAL This doument applies to strutural insulated panels (SIs), whih shall be defined as a strutural faing material with a foam ore. This doument does not apply to the design of reinforement materials whih may be inorporated into SIs, suh as dimensional lumber or old-formed steel. All other materials shall be designed in aordane with the appropriate ode adopted design standards. It is intended that this doument be used in onjuntion with ompetent engineering design, aurate fabriation, and adequate superision of onstrution. NTA, In. does not assume any responsibility for error or omissions in this doument, nor for engineering design, plans or onstrution prepared from it. It shall be the final responsibility of the designer to relate design assumptions and referene design alue, and to make design adjustments appropriate to the end use. 1.. DESIGN ROCEDURES This doument proides requirements for the design of SI panels by the Allowable Stress Design (ASD) method. The tehnial basis for this doument is the AA lywood Design Speifiation Supplement 4 Design & Fabriation of lywood Sandwih anels 1, whih is adopted by referene in the International Building Code (IBC). Some proisions of the design guide hae been modified to more losely model the atual behaior of the SI system desribed in this report. The design proedures proided herein generally assume uniform loads applied to a simply supported member. General loading and support onditions may be ealuated using rational analysis methods onsistent with the methodology proided herein. If finite element analysis software is used, the designer must erify that the software onsiders shear deformations between model nodes as most ommerially aailable finite element software pakages only onsider shear deformations at the nodes DESIGN LOADS Minimum design loads shall be in aordane with the building ode under whih the struture is designed, or where appliable, other reognized minimum design load standards SERVICABILITY Strutural systems and members thereof shall be designed to hae adequate stiffness to limit defletion and lateral drift. The defletions of strutural members shall not exeed the limitations of the building ode under whih the struture is designed, or where appliable, other reognized minimum design load standards LOAD COMBINATIONS Combinations of design load and fores, and load ombinations fators, shall be in aordane with the building ode under whih the struture is designed, or where appliable, other reognized minimum design standards STRESS INCREASE Duration of load inreases in allowable stresses speified in the National Design Standard for Wood Constrution (NDS) shall not be applied to SI faings or ore materials regardless of omposition LIMITS OF USE This doument applies to NTA, In. listed SI panels only and shall not be used with unlisted SIs or SIs listed/ealuated by other agenies. The design shall be limited to the speifi panel thiknesses desribed in the listing report. This doument shall not be applied to spans, heights, or aspet ratios not bounded by the limits of the listing report extrapolation is not permitted. WEB: FAX: NTA IM 014 TI 01 SI Design Guide do age 1 of 1

3 . NOTATION Exept where otherwise noted, the symbols used in this doument hae the following meanings: Δ Total defletion due to transerse load (in.) Δ LT Total immediate defletion due to the long-term omponent of the design load (in.) Δ b Defletion due to bending (in.) Δ Defletion of ore under onentrated load applied to faing (in.) Δ i Total immediate defletion due to appliation of a single design load ating alone (in.) Δ s Defletion due to shear (in.) Δ nd Total immediate defletion onsidering seondary (-delta) effets (in.) Α Total ross setional area of faings (in. /ft) A Shear area of panel. For symmetri panels A 6 ( h + ) (in. /ft) Core thikness (in.) C e Eentri load fator, Setion C F Size fator for shear, Setion C Shear support orretion fator e Load eentriity, measured as the distane from the entroid of the setion to the line of ation of the applied load (in.) E b SI modulus of elastiity under transerse bending (psi) E Elasti modulus of ore under ompressie load (psi) E f Elasti modulus of faing under ompressie load (psi) F Allowable faing ompressie stress (psi) F t Allowable faing tensile stress (psi) F Allowable shear stress (through thikness) (psi) F ip Allowable shear load (in-plane) (plf) G SI shear modulus (psi) h Oerall SI thikness (in.) h o Referene SI thikness for size orretion fators (in.) I SI moment of inertia (in. 4 /ft) I f Faing moment of inertia (in. 4 /ft) K r Time dependent deformation (reep) fator for a speifi load type, Setion A3.5.3 L Span length (ft) L Shear span length (ft) m Shear size fator exponent M Applied moment (in.-lbf/ft) Applied axial or onentrated load (lbf/ft.) r Allowable axial load (lbf/ft) r Radius of gyration (in.) S SI setion modulus for flexure under transerse loads (in. 3 /ft) V Applied shear fore (through thikness) (lbf) V ip Applied shear fore (in-plane) plf w Uniform transerse load (psf) y Distane from the entroid to the extreme ompression fiber (in.) β arameter of relatie stiffness 3. USE CONSIDERATIONS 3.1. LOAD DURATION Duration of load inreases in allowable stress shall not be applied to SI faings or ores. Duration of load inreases may be applied to the design of onnetions and wood reinforement as permitted in appliable material design speifiations. WEB: FAX: NTA IM 014 TI 01 SI Design Guide do age of 1

4 3.. MOISTURE This doument applies to SI panels used under dry serie onditions. For SI faings of wood or wood omposites the in-use moisture ontent shall not exeed 19% TEMERATURE This Doument applies to SI panels used as strutural members were sustained temperatures do not exeed 100ºF. 4. BENDING MEMBERS 4.1. GENERAL Eah SI panel subjeted to transerse loads shall be of suffiient size and apaity to arry the applied loads without exeeding the allowable design alues speified herein. 4.. SAN OF BENDING MEMBERS For simple, ontinuous and antileered bending members, the design span shall be taken as the distane from fae to fae of support. When no bearing is proided, suh as when a panel is supported by a spline only (C < 1.0), the design span shall extend the full height/length of the panel BENDING MEMBERS FLEXURE GENERAL anel flexural strength under transerse loading shall satisfy both equations below: M F S (Eqn a) M t F S (Eqn b) 4.4. BENDING MEMBERS SHEAR GENERAL The atual shear stress parallel to the faing at the ore to faing interfae shall not exeed the adjusted shear design alue SHEAR DESIGN EQUATIONS The panel shear strength under transerse loading shall satisfy the following equation: V F C C A (Eqn. 4.4.) F SHEAR SIZE ADJUSTEMENT FACTOR, C F The allowable shear strength shall be multiplied by a adjustment fator for the depth of the panel. The shear size adjustment fator shall be alulated using Equation C m ho F (Eqn ) h SUORT ADJUSTEMENT FACTOR, C For panel ends supported by full bearing on one faing and uniform loads applied to the opposite faing, the shear adjustment fator, C 1.0 (see Figure A4.4.4) For panel ends without bearing, supported by a top/bottom spline only, with uniform loads applied to either faing, the shear adjustment fator, C, shall be based on testing speifi to the following parameters (see Figure A4.4.4): WEB: FAX: NTA IM 014 TI 01 SI Design Guide do age 3 of 1

5 1. anel manufaturer;. Spline type, as it relates to the withdrawal/pullout strength of the fasteners (e.g. speifi graity for wood plates); 3. Fastener type and penetration Where C is less than 1.0, the allowable shear strength may be inreased if the spline/fastener ombination has a design withdrawal/pullout strength greater than the design withdrawal/pullout strength of the C assembly. The inrease in strength shall not exeed the differene in the design withdrawal/pullout strength between the stronger assembly and the C assembly Figure 4.4.4: C Support Conditions SHEAR DESIGN FORCE When alulating the shear fore, V, in bending members: a) For panels supported by full bearing on one faing and uniform loads applied to the opposite faing (C 1.0), uniformly distributed loads within a distane from the supports equal to the depth of the panel, h, shall be permitted to be ignored. b) For all other support and loading onditions (C < 1.0), no load applied to the panel may be ignored and V shall be taken as the full reation at the support under onsideration. Figure 4.4.5: Design Shear Fore WEB: FAX: NTA IM 014 TI 01 SI Design Guide do age 4 of 1

6 4.5. BENDING MEMBERS DEFLECTION GENERAL Defletion shall be alulated by standard methods of engineering mehanis onsidering both bending defletions and shear defletions DEFLECTION EQUATION Defletion of a simply supported panel under uniform transerse load only shall be alulated as follows: 4 5wL wl Δ Δb + Δs + (Eqn. 4.5.a) 384EbI AG Defletions for panels subjeted to ombined loads shall onsider the effets of axial load (-delta effets). The total defletion of panels under ombined loads may be approximated as follows. Δ Δ nd (Eqn. 4.5.b) 1 r LONG-TERM LOADING Where defletion under long-term loading must be limited, the total defletion, inluding reep effets shall be alulated as follows: ΔT K r Δi (Eqn ) i Table 1: Kr Based on Load Type 1 Load Type ES/XS Core Urethane Core D, F, H, T S, L E, W, R, L r, F a Table alues are for OSB faings used under dry serie onditions. Load types are as defined in ASCE DEFLECTION LIMITS The total defletion of strutural or non-strutural bending members, inluding onsideration for long-term loading, shall not exeed the more restritie of the following: a) the span diided by 10 (L/10); b) the limitations of the building ode under whih the struture is designed; ) or, other reognized minimum design load standards. WEB: FAX: NTA IM 014 TI 01 SI Design Guide do age 5 of 1

7 4.6. BEARING AND CONCENTRATED LOADS ON FACINGS MINIMUM SUORT WIDTH A minimum support width of 1.5-inhes shall be proided at all supports where the SI is designed for bearing (C 1.0). The bearing support shall be ontinuous along the end of the panel BEARING STREGNTH Where a full-depth strutural spline is proided at a point of bearing, the bearing strength shall not exeed the design bearing strength of the faings or spline, whiheer is less Where a full-depth strutural spline is not proided at a point of bearing and the bearing fae of the panel is supported by the ore only. The allowable bearing strength shall be limited to the load produing a long-term total ompression of the ore equal to 1/8-inh. Long term defletions shall be alulated in aordane with Setion The ore ompression defletion shall be alulated using the omponent material properties of the faing and the ore onsidering the faing as a beam on an elasti foundation. Formulas for ommon ases (Figure 4.6..) are proided in Equations 6...a and 6...b. Equations are for loads uniformly applied along the end of the panel. Figure 4.6..: Bearing on Faings Case A: Case B: Δ (Eqn a) 3 4E f I f β Δ (Eqn b) 3 8E f I f β 3E E I β 4 (Eqn ) f f WEB: FAX: NTA IM 014 TI 01 SI Design Guide do age 6 of 1

8 5. COMRESSION MEMBERS 5.1. GENERAL Eah SI panel subjeted to ompressie loads shall be of suffiient size and apaity to arry the applied loads without exeeding the allowable design alues in this setion COMRESSION MEMBERS LOAD ECCENTRICITY The panel ompression strength under axial loading shall satisfy the following equation: e where e e f C F A (Eqn a) The eentri load fator shall be alulated using Equation 5.1.1b onsidering a minimum eentriity equal to not less than one-sixth the oerall panel thikness ( e h 6 ). C e ey 1+ r 1 1L 3 se r A E (Eqn b) + f b 3ey A GI COMRESSION MEMBERS GLOBAL BUCKLING The ritial bukling load for a pinned-pinned olumn under axial loading shall satisfy the following equation: r where r 3 ( 1L) π EbI π E bi 1 + ( 1L) AG (Eqn. 5.1.) COMRESSION MEMBERS BEARING The axial ompressie load shall not exeed the bearing strength of the supporting materials. The bearing strength of the supporting materials shall be erified in aordane with the appropriate design speifiation. Where one or more of the SI faings are not in bearing, the onnetion between the faings and the spline shall be designed to transfer the full load from the faings to the plate. 6. TENSION MEMBERS 6.1. GENERAL A ontinuous load path shall be proided to transfer tension fores through the struture in a way that does not impart tensile loads to the SI panel faings or ore. WEB: FAX: NTA IM 014 TI 01 SI Design Guide do age 7 of 1

9 7. COMBINED LOADS 7.1. GENERAL anels subjeted to ombined loads shall of suffiient size and apaity to arry the applied loads without exeeding the allowable design alues in this setion COMBINED COMRESSION, TRANSVERSE BENDING AND IN-LANE SHEAR anel strength under ombined axial ompression, transerse bending and in-plane shear shall satisfy the following interation equations: e r M V max ip F S F ip M V max ip F S F ip (Eqn a) (Eqn b) For simply supported beam olumns M max shall equal: M wl max Δnd (Eqn ) 8. CONNECTIONS 8.1. GENERAL Connetions between SI panels, splines, plates, and non-si assemblies shall be designed in aordane with the appropriate material design standard referened in the appliable building ode. 9. SHEAR WALLS AND DIAHRAGMS 9.1. GENERAL SI panel shear walls and diaphragms ating as elements of the lateral fore-resisting system shall be designed in aordane with this setion. 9.. DEFINITIONS 9.3. SHEAR WALLS DEFINITIONS SHEAR WALL ANCHORAGE SHEAR WALL STRENGTH SHEAR WALL DEFLECTION 9.4. DIAHRAGMS WEB: FAX: NTA IM 014 TI 01 SI Design Guide do age 8 of 1

10 10. REFERENCES 1. AA. lywood Design Speifiation Supplement 4: Design and Fabriation of lywood Sandwih anels. Doument U814-H. Marh ASTM D198. Standard Test Methods of Stati Tests of Lumber in Strutural Sizes. ASTM International (ASTM). Conshohoken, A. 3. Taylor, S.B., Manbek, H.B., Janowiak, J. J., Hiltunum, D.R. Modeling Strutural Insulated anel (SI) Flexural Creep Defletion. J. Strutural Engineering, Vol. 13, No. 1, Deember, Timoshenko, S.., Gere, J.M. Theory of Elasti Stability. Seond Edition. MGraw-Hill Young, W.C., Budynas, R.G. Roark s Formulas for Stress and Strain. Seenth Edition. MGraw-Hill Zenkert, D. The Handbook of Sandwih Constrution. Engineering Materials Adisory Series Ltd WEB: FAX: NTA IM 014 TI 01 SI Design Guide do age 9 of 1

11 AENDIX AND COMMENTARY A1. DERIVATION OF ENGINEERING ROERTIES FROM TEST DATA The manner in whih laboratory test data is used is the primary differene between the methodology presented in this guide and the historial approahes for justifiation of SI panels. Historial approahes are largely based on diret use of E7 test data. Unlike historial approahes, this guide uses engineering mehanis to establish models for the test data. These models are applied to the test data to yield general engineering properties that are used as the basis for performane. The adantages of the engineering mehanis approah oer the historial approah are many. Some adantages inlude: basis for use as a strutural material is onsistent with other ode reognized strutural materials; improed statistial signifiane behind oerall panel behaior; improed understanding of panel behaior by separate onsideration arious limit states; generalization of properties to permit engineered design of support and loading onditions that annot be simulated in the laboratory. A1.1. TRANSVERSE BENDING STIFFNESS anel stiffness under transerse load is determined using the load-defletion data from tests performed in aordane with ASTM E7. This proess begins by reduing the data from eah transerse load test into two alues, the apparent bending modulus, E a, and a shear onstant, K s. By obtaining these two alues from multiple test onfigurations the elasti modulus, E b, and the shear modulus, G, are deried using a proedure similar to that desribed in the appendix of ASTM D198. A TEST ROGRAM The test program shall onsist of transerse load tests onduted in aordane with ASTM E7. Speimen onfigurations should be seleted with regard to the range of spans and panel thiknesses used by a gien manufaturer. At a minimum, it is reommended that not less than the minimum and maximum panel thiknesses are tested at their minimum and maximum spans, in eah orthogonal diretion (4 series of tests, 1 speimens, in eah diretion). It is reommended that additional speimens are tested so not less than 8 total speimens are tested, in eah orthogonal diretion (assuming faing is orthotropi), during the initial qualifiation. The onfiguration of the speimens between the upper and lower limits of thikness and span should be seleted based on the alulated alue of K s (see setion A1.1.3) with the goal of obtaining data points that are approximately equally spaed between the alues for K s. With regard to test proedure, efforts should be taken to isolate bending defletions from other soures of deformation during the test. Aordingly, it is reommended that panels are tested with a single solid top and bottom plate, defletion measurements are taken from the loaded surfae of the panel and deformations at the supports are measured and subtrated from the measured midspan defletions. A1.1.. AARENT BENDING MODULUS The apparent bending modulus, E a, is an elasti bending modulus speifi to a partiular panel support and loading onfiguration. Unlike the true elasti modulus, E b, the apparent bending modulus aounts for both bending and shear distortions. Using the test load-defletion data, the apparent bending stiffness, E ai, is alulated for eah test speimen (see Table A1). In this equation, the term w/δ is taken as the slope of a line best-fit through the load-defletion data orresponding to the antiipated range of in-serie loads. This range is reommended to be taken as 5% to 100% of the allowable load with the allowable load alulated as the ultimate strength diided by 3. The apparent bending modulus, E a, is alulated by diiding the bending stiffness by the moment of inertia. Considerations regarding data seletion when determining the apparent bending modulus inlude: 1. The load-defletion plot for the test data should be reiewed to erify that the data points used for the regression are within the region of linear response.. The span used in the alulation of E a shall be taken as the enter-to-enter spaing of the pin and roller supports and not the lear span between bearing plates. 3. The method of defletion measurement used in the test must be assessed. The data should orrespond to the midspan defletion minus the aerage of the defletions ourring at the supports. The defletion apparatus required in E7 aomplishes this automatially, but additional gauges loated oer the supports may be used to ahiee the same result. 4. The method of loading used in the test must be assessed. ASTM E7 permits loading using a auum method or bag method. The hoie of loading method affets the manner in whih the defletion readings are taken. Using the auum method it is possible to measure defletions from the loaded surfae, whereas the bag method requires defletions to be measured from the supported surfae. Where defletions are measured from the supported surfae it is not possible to measure and subtrat out support defletions, as a result the apparent stiffness will be redued. Additionally, if solid lumber splines are not proided at eah end of the speimen, loal WEB: FAX: NTA IM 014 TI 01 SI Design Guide do age 10 of 1

12 defletions at the supports (see Setion 4.6.) further redue the apparent stiffness and will result in a non-linear hook in the 1/E a erses 1/K s plot. When using load-defletion data subjeted to this effet, it is reommended that the data orresponding to a K s (see Setion A1.1.3) less than 50 are exluded from the analysis as the support defletions omprise a signifiant perentage of the midspan defletions for speimens below this limit. A SHEAR CONSTANT A shear onstant is also determined from eah test. This onstant assigns a alue to the test onfiguration and aounts for the depth of the panel, span length, and arrangement of the applied load. This alue is deried for a gien test onfiguration by equating the defletion equation using the apparent bending modulus to the defletion equation onsidering bending and shear deformations separately. An example of this formulation is proided below for a simply supported panel subjeted to a uniformly applied load. Table A1 proides equations for other loading and support onfigurations. Reduing this equation to a linear equation yields: 4 4 5wL 178 5wL 178 3wL + (Eqn. A1.1.3a) 384E I 384E I A G a b 1 E a I E G 40A L b (Eqn. A1.1.3b) The portion after the 1/G term is taken as the onstant K s. 40A L K s 384I 144 (Eqn. A1.1.3) It should be noted that the general formulation for shear deformation inludes a dimensionless onstant, κ, whih desribes the shear stress distribution aross the shear area, A. For isotropi retangular setions this onstant typially ranges from 0.84 to 0.86; howeer, for the purposes of this analysis this onstant is ombined with the shear modulus, G (i.e. G κ G atual). Test Configuration Simply Supported Uniform Load Simply Supported oint Load at Midspan 1 Defletion at midspan. Δ Δ Table A1: Transerse Stiffness Equations Defletion Apparent Bending Shear Formula 1 Stiffness, E ai (psi-in. 4 ) Constant, K s 4 5wL 178 3wL 5 + L w 40A L E I EbI AG a K s Δ 384I 3 3 L 178 L 1 L A + L E I E I A G a K s Δ 1I b 4 A BENDING AND SHEAR MODULI The purpose of the equations in Table A1 is to linearize the test data aross speimens of arious depths, spans, and loading onditions (Equation A1.1.4). Eah test yields one point on this line, with x 1/K s and y 1/E a. The elasti modulus, E b, and shear modulus, G, are determined from a line best-fit through all data points with E b 1/Y-Interept and G 1/Slope y mx + b + (Eqn. A1.1.4) E G K E a As with all experimental orrelations, some satter is expeted; howeer, if the data exhibits non-linear behaior at either end of the plot the test method should be more losely examined to determine whether bending deformations are suffiiently isolated from other deformations during the test (see Setion A1.1.). s b WEB: FAX: NTA IM 014 TI 01 SI Design Guide do age 11 of 1

13 A LIMITS OF USE In aordane with standard engineering pratie, extrapolation beyond the limits of the test program should be aoided. For properties determined using the method desribed herein, the limits of use are established by the shear onstant, K s. Additionally, it is reommended that use of the parameters is limited to panel thiknesses bounded by the maximum and minimum tested thiknesses. COMMENTS, QUESTIONS AND ERROR REORTING All efforts hae been made to ensure the auray of this doument; howeer, if errors are found please ontat Eri Tompos,.E., S.E. ia at etompos@ntain.om. WEB: FAX: NTA IM 014 TI 01 SI Design Guide do age 1 of 1