BASE PLATE-c1BASE PLATE DESIGN-IS 800-2007SELECT THE EDGE CONDITIONSFOR BASE PLATECASE 2Plate supported on 3 sideyyCASE 3Plate supported on 4 sideynCASE 4Plate supported on 2 sidey

BASE PLATE BP-5SUMMARYSize of the column UB254x146x43300 mmCASE 2Plate supported on 3 sidetb=6.5 mmFactored loads:CASE 3Plate supported on 4 sidetb=7.6 mmMax. compression196.206Node:145 mmCASE 4Plate supported on 2 sidetb=4.4 mmMax. tension179.032Node:1CASE 5Plate under tensiontb=19.3 mmMax. shear50.897Node:1FOR COMPRESSION350 mmHence provide thickness of bottom plate=24.0 mm

Assume the base plate size as 300 X350mm2260 mmMax. compression196.206Bearing strength of concrete=0.45 fck=0.45 x 25=11.25N/mm2

Hence base pressure -(w)=196.206=1.87N/mm2300 mmX350 mm< than 0.45times the bearing strength of concrete Hence ok Ratio a/d0.50.60.70.80.911.21.42Plates supported on three sides0.060.0740.0880.0970.1070.1120.120.1260.132CASE 1EDGE CONDITION- CANTILEVERPANEL 1147.3 mma1=45 mmSteel Grade, fy =250N/mm2d1=300 mmConcrete Grade, fck =25N/mm2mo =1.1Bending moment Md=1.87X2043.04c/c distance between bolt along y dir=120.02c/c distance between bolt along x dir=120.0Mukhanov's chart,=1910.2424N-mm Ratio a/d0.50.60.70.80.911.21.422.1100Plates supported on 3 sides0.060.0740.0880.0970.1070.1120.120.1260.1320.1330.133a3Interpolation0ERROR:#N/AThickness of plate required =(6 Md mo /1.2 b fy)0ERROR:#N/A (IS 800- 2007,Clause 8.2.1.2)00Assuming width of the plate b =1.00mmInterpolation1.20.12treqd =6.5mm1.40.1261.380.12550.0000

N/mm2SECTION A-ACASE 2Edge condition - Plate supported on three sides.PANEL 2Assume thickness of stiffener=12mma1 =146.4 mmChecking whether panel acting as cantilever a1=146 mmd1 =105.8 mm(Length of free edge)a1/d1 >0.5 hence analysed as plate supported on 3 sideCantilever moment Md =NOT APPLICABLEfree edgea1=1.3837429112d1=d1106 mmHence coefficient=0.126Hence moment on the base plate Md=0.126*1.87*105.8^2=2637.45N-mmThickness of plate required =(6 Md mo /1.2* b fy)As per IS 800- 2007,Clause 8.2.1.2Assuming width of the plate b =1.0treqd =7.62mm(From Compression only)

CASE 3Edge condition - Plate supported four sides.PANEL 3Checking whether panel acting as cantilever Mukhanov's chart,a1 =100.0 mm Ratio a1/d111.11.21.31.41.51.61.71.81.922.1100d1 =100.0 mm(Length of free edge)a1/d1 >0.5 hence analysed as plate supported on 4 sidePlates supported on 4 sidesa10.0480.0550.0630.0690.0750.0810.0860.0910.0940.0980.10.1250.125

a1=1d1Cantilever moment Md =NOT APPLICABLEa20.0480.0490.050.050.050.050.0490.0480.0480.0470.0460.0370.037Hence coefficienta1=0.048a2=0.048Hence moment on the base plate Md=897.60N-mmThickness of plate required =(6 Md mo /1.2* b fy)Interpolation10.0480.048Assuming width of the plate b =1.01.10.0550.0491.000.0480.0000.048treqd =4.44mma1a2CASE 4Edge condition - Plate supported two sides.PANEL 4click below to see the chartsa=100.0 mmChecking whether panel acting as cantilever Refer Page-243 Table-54 of Theory of Plates and shells by S. Timoshenko & S. Krieger, As per IS 800- 2007,Clause 8.2.1.2b=50.0 mm(smaller span)ORa1/d1 >0.5 hence analysed as plate supported on 2 sideMOODY CHARTb=2(for two side edge supported)aColumn propertiesHence coefficienta1=0.050Cantilever moment Md =NOT APPLICABLEA=5480mm2rx109.3mma2=0.048H=259.6mm2ry35.2mmbf=147.3mmZx504100mm3Hence moment on the base plate Md=233.75N-mmt7.2mmZy92000mm3Thickness of plate required =(6 Md mo /1.2* b fy)T12.7mmAssuming width of the plate b =1.0Ix65440000mm4Iy6770000mm4treqd =2.27mmCheck for weld size connecting base plate to ColumnBase plate under Tension(As per Cl. 10.3.5)Total length available for welding along the periphery of columnSupport reaction =179.032(Max Tension)FLANGE TO BASE PLATE CONNECTION tf =12.7mmAssume 4Nos20dia H.D boltsGrade4.6(Bearing type bolt)Axial load shared by two flange=98.103 tw =7.2mmTension capacity of bolt Tdb = Tnb / gmbmb =1.25Axial load shared by each flange=49.0515fu=410N/mm2Tnb = 0.9 fub An < fyb Asb (mb / mo)fyb=240N/mm2gmw1.25Shank area of the bolt(Asb)=314.16mm2fub =400N/mm2Total load on weld for designing one flange=49.0515Net tensile area at the bottom of threads (An)=245.04480000000004

Length available to accommodate weld on each flangeLa=287.40000000000003 0.9 fub An =88.21612800000001Assume 6.0weld fyb Asb (mb/mo)=85.68Strength of weld per mm length=Lw tt fu/3 gmw=795.3577308356N/mmTnb =85.68Tension capacity of single bolt Tdb = 68.54Effective length of weld required on Each flange=49.0515=61.67224897464052Tension/bolt (Tb) =44.76Hence O.K795.3577308356Additional plate is not required to acccomodate welding

WEB TO BASE PLATE CONNECTIONAxial load shared by web=49.0515Length available to accommodate weld on each flangeLa=468.40000000000003Diagonal distance from bolt centre to web =84.86Effective length of weld required on Each flange=49.0515=61.67224897464052Moment in the plate due to bolt tension=(44.76/3 x 1000 x 84.86)795.3577308356=1266111N-mmAdditional plate is not required to acccomodate weldingThickness of plate required =(6 Md mo /1.2* b fy)Design of stiffener plate (Web stiffener plate)Assuming width of the plate b =1.0Design of stiffner plate -Assuming the width of the plate=75.0need to check widthMoment at the face of the column web -(for compression in the coulmn)treqd =19.27provide base plate thickness=24.01.87*259.6/2*(300/2)^2/2=2730667.5N-mmShear capacity of bolt:Moment at face of stiffener (due to bolt tension) -Vnsb =fu An / 3 =56.59Vdsb =45.27KN44760*120*1.414/2 =3797438.4N-mmBearing capacity of the bolt:Assume plate thickness -10.0Vnpb =2.5 kb d t fuKb =Min (e / 3do, p/ 3 do - 0.25, fub/fu, 1)Height of plate required =(6 Md gmo / b fy)0.57e =37.4=100.13=280439.99999999994fu =410410Hence, Provide stiffner plate height as200.0Vdpb =224.35do =22.02.0p=120.0Therefore Shear capacity of single Bolt=56.59KNHence O.KDesign of Stiffner Plate (flange stiffener)Moment at the face of the column flange - (for compression on column)1.87*(259.6/4+45.2)*((76.35^2)/2=600090.86N-mmMoment at face of stiffener (due to bolt tension) -44760*(259.6-120)/2=3124248N-mmHeight of plate required =(6 Md mo /1.2* b fy)Assume plate thickness -10.0=82.91Hence, Provide stiffner plate height as100.0Design for Shear Key (check 1)Shear key size 100x12thk. crossH (max) =50.897Provide150mm deep shear key50.897Ze of the section =20288mm3Zp of the section =33600mm3Ze/Zp =0.6udl on the shear key =50897/150=339.32N/mmHence cantilever moment on the shear key (M)=339.32*150^2/2 =3.82 KN-mSection classification as per Table- 2 of IS 800: 2007:d/t =8.33e =1.0PlasticDesign bending strength Md = bZpfy/mo=100.0

For a Plastic section, b =1Md = 7.64KN- mM < Md, Hence O.KHence provide shear key size as100x150x12

Shear key (A/c Subramanian book)Required bearing area of shear lugAlg=V/0.45 x fckAlg=4524.1778mm2

Assume Shear lug width W=200.0H-G=22.630000000000003Assume grout depth G=50.0

Required depth of shear lug=50+22.63=72.63

Factored cantilever end moment acting on unit length of the shear lugMlg =(V /W)*(H+G)/2=9242N-mmShear lug thicknesstlg=[(4 xMlg /(fy /m0)]^0.5