Block shear resistance

A study on the comparison of Block Shear Resistance as per IS code is done to validate the results of IDEA StatiCa Connection design software.

Type of Connection: Gusset Plate

Unit System: Metric

Design Code: IS 800

Plate Material: IS 2062 Grade Steel

Bolt: M16, Grade 8.8

Geometry:

 Applied Forces:

N = 800 kN

V = 0 kN

M = 0 kN

Procedure:

Block shear resistance is checked on a thin gusset plate (thickness 8 mm), which is designed to fail while other components are still undamaged

IS Code:

Fig1. Gusset plate dimenions and failure of plate in block shear

As per Clause 6.4.1 of IS 800: 2007, the block shear strength (Tdb) of connection shall be taken as the smaller of

\[ T_{db} = \frac{A_{vg} f_y}{\sqrt{3} \gamma_{m0}} + \frac{0.9 A_{tn} f_u}{\gamma_{m1}} \]

or

\[ T_{db} = \frac{0.9 A_{vn} f_u}{\sqrt{3} \gamma_{m1}} + \frac{A_{tg} f_y}{\gamma_{m0}} \]

where:

  • Avg, Avn = minimum gross and net area in shear along bolt line parallel to external force
  • Atg, Atn = minimum gross and net area in tension from the bolt hole to the toe of the angle, end bolt line, perpendicular to the line of force
  • fu, fy = ultimate and yield stress of the material

Manual Calculations:

Avg = (60+60+42) *8*2 = 2592 mm2

Avn = ((60+60+42) – 2.5*18) *8*2 = 1872 mm2

Atg = (60) *8 = 480 mm2

Atn = (60-18) *8 = 336 mm2

IDEA StatiCa Connection:

The resistance of plate in IDEA is determined at 5% limit strain

Fig 2: Equivalent Stress

Fig 3: Limiting Strain

Comparison:

Steel Grade

fy

[MPa]

fu

[MPa]

Tdb [kN]

IS 800

Tdb [kN]

IDEA

IDEA/IS 800 
E 165 (Fe 290)16529029527292%
E 250 (FE 410 W) B25041042840394%
E 300 (Fe 440)440300473472100%
E 350 (Fe 490)490350534544102%
E 410 (Fe 540)540410599628105%
E 450 (Fe 570) D450570640669105%
E 450 (Fe 590) E450590655669102%


IDEA StatiCa Connection design results of block shear resistance are similar to manual computation according to IS 800: 2007. IDEA StatiCa Connection results are a little bit on the conservative side for low-grade steels and slightly unconservative (5 % at most) for high-grade steels. The reason is that the ultimate strength does not affect the results of IDEA Connection for plates. 

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