pl LRFD ASD - Structural Engineering Software

1 60 / design GUIDE 1, 2ND EDITION / BASE PLATE AND ANCHOR ROD DESIGN2. Assume a 14-in. 14-in. base plate. The effective ec-centricity is Then, e > ekern; therefore, anchor rods are required to resist the tensile force. The anchor rods are assumed to be from the plate edge. 3. Determine the length of bearing. thus,8. Determine required plate thickness: Note: Since the Mpl is expressed in units of , the plate thickness expressions can be formatted with-out the plate width (B) as such:9. Use plate size: N = 19 in. B = 19 in. t = 14 example : Large Moment Base Plate design , Triangular Pressure Distribution ApproachDesign the base plate shown in Figure for an ASD and lrfd required strength of 60 and 90 kips, respectively, and moments from the dead and live loads equal to 480 and 720 kip-in.

2 , respectively. The ratio of the concrete to base plate area (A2/A1) is Bending is about the strong axis for the wide flange column W8 31 with d = bf = 8 in.; Fy of the base plate and anchor rods is 36 ksi and fc of the concrete is 3 requ crity kip-in. ksi =44 11 10 90 361 17 ..tMFa reqa crity kip-in. ksi =44 7681 67361 19 ..LRFDASDPMPAuup=== 907200 60 0853 020 60 1 71 kips kip-in.. (. )( .)(). (. )(( .)3 0 PMPAaap=== 604800 85 30 22 501 73 01 kips kip-in. ( .)(. ) ( ).( .)(.))..2 502 041 PAp = ksiLRFDASDe = 720 kips = = 480 kips = design example with large = =f3 061412 ksi in. in. kips = =f 2 041412 ksi in.

3 In. kipsLRFDASDA= ( )+ 26826843 06 146905 57203 06 = ( )+ 17817842 04 146605 54802 04 = 27. PAp13 06=. ksiAISC design Guide 1, 2nd EditionBase Plate and Anchor Rod DesignVerification ExampleDESIGN GUIDE 1, 2ND EDITION / BASE PLATE AND ANCHOR ROD design / 61 Anchor rods are placed at a 12-in. edge distance. The required moment strength, Mu pl or Ma pl, for a 1-in. strip of plate due to the tension in the anchor rods is The required moment strength due to the bearing stress distribution is critical. The required plate thickness is: Use a 14 14 1 -in. base Determine the required tensile strength of the anchor rod.

4 5. Determine the required plate thickness. The moment for this determination is to be taken at the critical plate width. This is determined by assuming that the load spreads at 45 to a location of the col-umn. The width is then taken as twice the distance from the bolt to the critical section for each bolt, provided that the critical section does not intersect the edge of the plate. The critical section, as shown in Figure , is at 14 (8)/2 = in. The required moment strength, Mu pl or Ma pl, for a 1-in. strip of plate, determined from the bearing stress distri-bution in Figure , isLRFDASDTTT urodu= == = in. kips kips2902282 kipsTTTaroda= == = in.

5 Kips kipsLRFDASDMu pl= ( )+ 1 203223 ( ..) ksi in. ksi ksi ( .)3 222 in. = in- pl ksi in. ksi ksi= ( )+ 0 803222 ( ..)) (.) 3 222 in. = in- u pl= kips in . in. in in. 22832152 3215.(..)( ..) a pl= = kips in . in. in . in. i15232152 32157 60.(..)( ..). =4 12 50 90 361 24( .).. ksi 8331 67361 24( .)( . ). ksiFigure Critical plate width for anchor bolt (tension side).Project:Engineer:Descrip:Verificat ion ExampleJavier Encinas, PEBase Plate VerificationPage # ___7/20/2014 ASDIP Steel BASE PLATE Section ..WidthLengthColumn ..Plate ..ConcreteSupportRod Offset.

6 Thickness of Grout .. LOADS (ASD)Vertical Load P ..Bending Moment M ..Horizontal Load V .. design Eccentricity e .. design Eccentricity Is > Steel Strength Fy ..Pier Concrete Strength f' LOADED PLATESC antilever ModelBearing Stress fp ..Critical Section @ Long mCritical Section @ Short nPlate Thickness tp .. ModelBearing Strength Fp/ ..Critical Section @ Int n' . design Moment @ Plate ..Plate Thickness tp .. PLATES WITH MOMENTB lodgett MethodMax. Bearing Stress fp ..Bearing @ Critical SectionMoment @ Critical SectionMoment due to Rod TensionDesign Moment @ Plate ..Plate Thickness tp .. MethodMax. Bearing Stress fp.

7 Bearing @ Critical SectionMoment @ Critical SectionMoment due to Rod TensionDesign Moment @ Plate ..Plate Thickness tp .. :Engineer:Descrip:Verification ExampleJavier Encinas, PEBase Plate VerificationPage # ___7/20/2014 ASDIP Steel BASE PLATE DESIGNRod Material Specification ..Anchor Rod Size ..F1554-36(4) Rods , fya = ksi, futa = ksi1" diam. x in Is Cracked at Service Load LevelTension Analysis (kip)Total Tension Force N ..Tension Force per Rod Ni ..Anchor Reinf: Use 2 Bars #5 per Mode Nn N / Nn/ Steel Strength NsaRebars Strength NrgConc. Breakout NcbgPullout Strength NpnSide Blowout NsbgN / Nn/ Tension design Ratio .. Analysis (kip)Shear Taken by Anchor Rods onlyTotal Shear Force V.

8 Force per Rod Vi .. kipAll Anchor Rods Are EffectiveNo Reinforcing Bars ProvidedFailure Mode Vn V / Vn/ Steel Strength VsaRebars Strength VrgConc. Breakout VcbgConc. Pryout / Vn/ Shear design Ratio ..OKTension-Shear InteractionCombined Stress Ratio .. OF RESULTSD esign Moment @ Plate ..Plate Thickness tp ..Max. Bearing Stress fp ..Bearing Strength Fp/ ..fp / Fp/ design Ratio .. IS DUCTILEDESIGN CODESS teel design ..Base plate design ..Anchorage design ..AISC 360-10 (14th Ed.)AISC design Series # 1 ACI 318-11 Appendix D2 Project:Engineer:Descrip:Verification ExampleJavier Encinas, PEBase Plate VerificationPage # ___7/20/2014 ASDIP Steel BASE PLATE BreakoutShear Breakout3 Project:Engineer:Descrip:Verification ExampleJavier Encinas, PEBase Plate VerificationPage # ___7/20/2014 ASDIP Steel BASE PLATE Section.

9 WidthLengthColumn ..Plate ..ConcreteSupportRod Offset ..Thickness of Grout ..Wp1Wp2Lp1Lp2ininininininOKOKOKOKV ertical Load P ..Bending Moment M ..Horizontal Load V .. design Eccentricity e .. design Eccentricity Is > Steel Strength Fy ..Pier Concrete Strength f'cksiksiBearing / ( * ) = ksiBearing strength= * *= ksiACI factor = strength ratio == / < OKCritical section m =Critical section n = * ( - * ) = * ( - * ) = inAISC-DG#1 [4 * * ( + ) ] * = #1 + -= inControlling sectionMax ( , , * ) = inPlate * / 2 = k-in/inPlate thickness= *= inAISC-DG#1 :Engineer:Descrip.

10 Verification ExampleJavier Encinas, PEBase Plate VerificationPage # ___7/20/2014 ASDIP Steel BASE PLATE * 12 / = in > L / 6 = / 6 = lengthY = * ( / 2 + ) - *[ + ] -= inAISC-DG#1 bearing * * / 2 - = kipAISC-DG#1 at critical * (1 - / ) = ksiMoment due to bearingMb = * / 2 + ( - ) * / 3 = k-in/inMoment due to tensionMt = * [ - ( / 2 - )] / [2 * ( - ( / 2 - ))] = k-in/inPlate thickness== inAISC-DG#1 :Engineer:Descrip:Verification ExampleJavier Encinas, PEBase Plate VerificationPage # ___7/20/2014 ASDIP Steel BASE PLATE Material Specification ..F1554-36 , Use (4) Rods , fya = ksi, futa = ksiAnchor Rod Size.