Composite Column Design 6b244

321136831.xls Design of Composite Columns to EC4 Column on Grid D/9 Ground to First Floor Job Description Redditch Job Number 10590 Length of column L = Effective Length = Aplied Axial Load = Max Moment about Major axis Myy = Max Moment about Minor axis Mzz =

7500 7500 7345 492 492

EC4 Clause

mm mm kN kNm kNm

Material Properties Structural Steel

3.3

Nominal Steel Grade = Nominal Yield Strength fy= Modulus of Elasticity Ea=

50 345 N.mm2 205 kN/mm2

Concrete Class Characteristic Strength fck= Secant Modulus of elasticity s.t. Ecm=

40 40 N.mm2 35 kN/mm2

Concrete 3.1 3.1.4.1

Reinforcing steel Type of steel Characteristic strength fsk= Modulus of elasticity Es=

460 N.mm2 205 kN/mm2

3.2.4

Partial Safety Factors gamma a = gamma c fundamental = gamma c for effective elastic flex stiff = gamma s = Design Strengths fyd=fy/gamma a = fcd=alpha c*fck/gamma c = fsd=fsk/gamma s =

1.05 1.5 1.35 1.15

Table 1

328.6 N.mm2 22.7 N.mm2 400.0 N.mm2

Check limits of acceptablility by hand 4.8.3.1(3) Is column Doubly symmetrical Is Concrete cover within limits Is X-sect A of Longit Rebar>0.04Ac Steel contribution factor Delta = 0.54 Section is within contribution limits Steel Section Properties Steel Section 305x305x158U.C. Breadth of section - b = 310.6 mm Depth of Section - h = 327.2 mm Thickness of Web - tw = 13.8 mm Thickness of flange - tf = 21.7 mm X Sect Area - Aa = 20100 mm2 2nd Moment Area about Major Axis Iay 386900000 mm4 2nd Moment Area about Minor Axis Iaz 125000000 mm4 Plastic Modulus - Wpa.y 2675000 mm3

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321136831.xls Plastic Modulus - Wpa.z

1225000 mm3 EC4 Clause

Reinforcement Diameter of Bars = Number of Bars = Area of Reinforcement As= Spacing of Reinforcement on Major = Spacing of Reinforcement on Minor = Concrete Area and Cover Breadth of concrete Bz= Depth of Concrete By= Area of conrete Ac = Cover Cz = Cover Cy =

20 4 1257 430 430

mm mm2 mm mm

500 mm 500 mm 228643 mm2 94.7 Cover is Ok 86.4 Cover is Ok

As/Ac = 4% of concrete area (mm2) =

0.55% There is adequate reinforcement for model 9146 There is adequate reinforcement for model

Design Checks Plastic Compression Resistance of Composite Cross-section

4.8.3.3

Npl.rd = Aa*fyd+Ac*fcd+As*fsd =

Eq 2

12290 kN

Evaluate the effective elastic flexural stiffnes of the composite cross-section for short term loading About the Major Axis Ea*Iay = Es*Isy = 0.8*Ecd*Icy =

79314500000 kNmm2 1.1908E+10 kNmm2 98795309618 kNmm2

Effective flexural Stiffness (EI)ey = or About the Minor Axis Ea*Iaz = Es*Isz = 0.8*Ecd*Icz =

1.9002E+11 kNmm2 1.9002E+05 kNm2

2.5625E+10 1.1908E+10 1.0423E+011

Effective flexural Stiffness (EI)ez = or

1.4176E+11 kNmm2 1.4176E+05 kNm2

Evaluate the Non-Dimensional Slenderness Lambda Npl.r =Aa*fy+Ac*0.85*fck+As*fsk=

15286 kN

Ncry = pi^2 * (EIey/l^2) =

33340 kN

Therefore Lambda y =

0.677

Ncrz = pi^2 * (EIez/l^2) =

24873 kN

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4.8.3.7

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321136831.xls

Therefore Lambda z =

0.784 EC4 Clause

Check resistance under Axial Compression Major Axis Phi = Reduction Factor X = Major Axis Compression Resistance = Major axis has sufficient axial capacity Minor Axis Phi = Reduction Factor X = Minor Axis Compression Resistance = Minor axis has sufficient axial capacity

0.810 0.796

4.8.3.8

9788 kN

4.8.3.8

0.950 0.672

4.8.3.8

8261 kN

4.8.3.8

Check for Second Order Effects check for second order effects needed

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4.8.3.10 0.30

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