Applies To
	Product(s):	STAAD.Pro
	Version(s):	All
	Environment:	N/A
	Area:	Steel Design
	Subarea:	Verifications
	Original Author:	Anisurya Ghosh, BSW-Structural Design, Bentley Kolkata

•  Introduction:

The following is a validation problem for a detailed calculation of the Russian SP 16 I section design.

• Validation Problem:

 

A 5 m long beam formed from a HD320X127 I section (Steel grade: S235), is checked for an applied UDL of -100 KN/m throughout the span.

 

• Input File:

STAAD PLANE
INPUT WIDTH 79
UNIT METER KN
JOINT COORDINATES
1 0 0 0; 2 5 0 0;
MEMBER INCIDENCES
1 1 2;
DEFINE MATERIAL START
ISOTROPIC STEEL
E 2.05e+008
POISSON 0.3
DENSITY 76.8195
ALPHA 1.2e-005
DAMP 0.03
TYPE STEEL
STRENGTH FY 253200 FU 407800 RY 1.5 RT 1.2
END DEFINE MATERIAL
MEMBER PROPERTY EUROPEAN
1 TABLE ST HD320X127
CONSTANTS
MATERIAL STEEL ALL
SUPPORTS
1 PINNED
2 FIXED BUT FX MZ
LOAD 1 LOADTYPE None TITLE LOAD CASE 1
MEMBER LOAD
1 UNI GY -100
PERFORM ANALYSIS
PRINT FORCE ENVELOPE NSECTION 2 ALL
PARAMETER 1
CODE RUSSIAN
BEAM 1 ALL
*CMN 5 ALL
SGR 1 ALL
GAMC2 1.1 ALL
GAMC1 1.1 ALL
TB 1 ALL
DFF 200 ALL
*BMT 100 ALL
TRACK 2 ALL
CHECK CODE ALL
FINISH

• Manual Calculation:

Section Properties:

 D= 320 mm, B= 300 mm, Tf= 20.5 mm, Tw= 11.5 mm, Ix= 30820 cm⁴, Iy= 9239 cm⁴,

 Wx= 1926.5 cm³, Sx= 1070 cm³, J= 225.1 cm⁴, H= 2.069*10^12 mm⁶

Maximum Bending Moment = 312.5 KN-m

Material Properties:

S235

E = 206000 MPa, fy = 235 MPa, γc1 = 1.1, γc2 = 1.1

Check for Flexure:

We need to satisfy eqn. 41 of SNiP SP16.13330.2011:

M = 312.5, W_n,min = W_x = 1926.5 cm³, Ry = 235 MPa, γc2 = 1.1

Then, M/( W_n,min*Ry* γc) = 0.6275 < 1 (OK)

STAAD.Pro value is 0.628 [Matching]

 

Check for Shear:

We need to satisfy eqn. 42 of SNiP SP16.13330.2011:

Q = q.l/2 = 250 KN, S = 1070 cm³, I = 30820 cm⁴, Rs = 0.58*235 MPa, γc2 = 1.1, tw = 11.5 mm

Then, QS/(I*tw*Rs*γc) = 0.5034 < 1.0 (OK)

Check for Lateral Torsional Buckling:

We need to satisfy eqn. 42 of SNiP SP16.13330.2011

 

Check for Combined Shear & Flexure:

We need to satisfy eqn. 44 of SNiP SP16.13330.2011

Check for Deflection:

(5*100*5⁴)/(384*206000*1000*30820*10^-8) = 0.0128 m

STAAD.Pro value is 0.0128 m [Matching]

Maximum member deflection = l/200 = 0.025 m

STAAD.Pro value is 0.0128 m [Matching]

Ratio = 0.0128/0.025 = 0.512

STAAD.Pro value is 0.51 [Matching]

 

• Summary Table:

Item	STAAD.Pro Value	Hand Calculated Value	% Deviation
Flexure Ratio	0.628	0.6275	0.0796
LTB Ratio	0.63	0.6275	0.3968
τxy	0	0	0.0000
Ratio for combined shear & Flexure	0.546	0.546	0.0000
λub	0.865	0.865	0.0000
λb	0.5629	0.5629	0.0000
Maximum Deflection	0.0128	0.0128	0.0000
Deflection Ratio	0.51	0.512	0.3922