钢结构柱脚设计小工具

Base Plate Design (Fixed Bases)

WITHOUT STIFFENER PLATES

INPUTS

Loads Base Plt.Section Properties Design Conc. str.Steel Strength Bolt strength Bolt info.Weld

Column Size Fc'Mx'My'Fxx Fyy Dp Bp Dc Bc Tc dc ed M Fy fcu fb Gr.pyp p weld Bolt p shear p tens Dia Nos.A tens S kN kNm kNm kN kN mm mm mm mm mm mm mm kNm kN N/mm2N/mm2N/mm2N/mm2Gr.N/mm2N/mm2mm n mm2mm UC3566008050450600600350350192706013045301243270215 4.61601953065598

DESIGN

BASE CHECK BOLT CHECK Min. Thick of Plate (Consider 1mm strip)Weld check

Column Size ex Tens.x z a M1C Ftt fmax Ft Pt Fs Ps Ratio b f Mx1Mx2Mmx thick tp'Ff Lwt fwt Lwv fwv mm(Y/N)mm mm mm kNm kN kN N/mm2kN kN kN kN r<1.4mm N/mm2kNmm kNmm kNmm mm kN mm N/mm2mm N/mm2 UC356217Y259454480274604 4.067.811098890.10125 4.0210415132393700100.254014.88 Loads Calculations

Fc' = Axial Comp. Load ex = Eccentricity = M/Fc'Ft = Tension per bolt = Ftt / (n/2)

Mx' = Moment about XX Tension will exist in the bolts, if eccentricity Pt = Tensile capacity of bolt = (pt) (A tens)

My' = Moment about YY is outside the middle third.Fs = Shear per bolt = Fy / n

Fxx = Shear along XX x = Length of base in compression Ps = Shear capacity = (ps) (A tens)

Fyy = Shear along YY = (m) (fb) (b') / [(m) (fb)+(pt)]r = Ratio (Fs) / (Ps) + (Ft) / (Pt) < 1.4

M = Equivalent moment Where m = modular ratio = Es/Ec = 15 (say) b = Cantilever strip = (Dp - Dc) / 2

= Mx' + (1 x ( b' / h' ) x My')z = Lever arm distance = (b')-(x/3) f = Pressure at face of column = fmax - [(fmax) (b/x)]

Where, b' =(Dp-ed) & h' =(Bp-ed) a = c/c of bolts = Dp - 2 (ed)Mmx = Mx1 + Mx2 = Max moment at face of column

Fy = Resultant shear Taking moment about C.L of the bolts in tension Where , Mx1 = (0.5) (b) (f) (b/3)

= SQRT(Fxx2+Fyy2)M1 = M + [(Fc') (a)/2] Mx2 = (0.5) (b) (fmax) (0.67 b)

Dp = Length of Base Plate C = Compressive force in concrete = M1 / (z)Thickness tp' = SQR (( 6 (Mmx)) / (1.2 (pyp))

Bp = Width of Base Plate Ftt = Tensile force in H.D bolts = C - Fc'

Dc = Col.Depth fmax = [(2) (C) / ((Bp) (x))]Weld check

Bc = Col.width Assume moment is carried by the column flanges the force in each flange,

Tc = Flange thk Ff = M / (Dc - Tc)

dc = Depth betn.fillets Lwt = Length resisting tensile force = 2 (Bc)

ed = Edge distance fwt = Stress on weld due to tension = Ff / [ (Lwt) (0.7) (S) ] < P weld

fb = (0.4)(fcu)Lwv = Length of weld resisting shear = 2 (dc)

fwv = Stress on weld due to shear = Fy / [ (Lwv) (0.7) (S) ] < P weld