Avg=8×(3×60+40)=1760 mm2
Avn=8×(3×60+40−3.5×22)=1144 mm2
Atg=8×40=320 mm2
Atn=8×(40−0.5×22)=232 mm2
Strength governed by block shear
Tdb1=fyAvg√3γm0+0.9fuAtnγm1
=250×1760√3×1.1+0.9×410×2321.25=299.43 kN
Tdb2=0.9fuAvn√3γm1+fyAtgγm0
=0.9×410×1144√3×1.25+250×3201.1=267.70 kN
Tdb=267.70 kN