Benchmark 4: Axial compression

Project file: CCD_Benchmark_C1.esa

SCIA Engineer Version R21.1

Introduction

Benchmark document: Composite Structures according to Eurocode 4 - Dujmović / Androić / Lukačević (2014)

Benchmark C1 given by the publication (pages 399-418) covers Composite column with concrete-filled circular hollow section subject to axial compression and verified using European buckling curves.

The column (3.0 meters long) is loaded by a compression force N_Ed of 7750 kN.

The cross-section has the following dimensions:

with:

Structural steel	Reinforcing steel	Concrete
fy = 355 MPa	fs = 500 MPa	fck = 30 MPa
Ea = 210000 MPa	Es = 210000 MPa	Ecm = 33000 MPa
Gamma_M = 1.00	Gamma_s = 1.15	Gamma_c = 1.50

 

Reference results

The reference gives following results:

Cross-section properties

Structural steel	Reinforcing steel	Concrete
Aa = 110 cm2	As = 58.9 cm2	Ac = 1128 cm2
Ia = 21732 cm4	Is = 7076 cm4	Ic = 10594 cm4

 

Compression check

χ	Npl,Rd	UCN
0.94	8723 kN	0.95

SCIA Engineer results

Cross-section properties

Compression check

 

Comments

Differences explained:

• page 405 - minor differences in steel section and concrete areas caused by the polygonal shape of CHS section

A_a = 110 cm² compared to 109.78 cm² in SEN

A_c = 1128 cm² compared to 1126 cm² in SEN

• page 405+406 - minor differences in moment of inertia for all components

I_s = 7076 cm⁴ compared to 7098 cm⁴ in SEN (reference is not using central moments of inertia for reinforcement bars)

I_a = 21732 cm⁴ compared to 21677 cm⁴ in SEN (circular shape)

I_c = 105094 cm⁴ compared to 104786 cm⁴ in SEN (circular shape)

These changes projects through the whole example resulting in minor differences at the end.

• page 411 - N_pl,Rd = 8723 kN compared to 8711 kN in SEN (circular shape)
• page 417 - unity of 0.95 compared to UC_N = 0.94 in SEN (circular shape + moment of inertia)