Steel · Connections: moment & splices

Bolted web splice calculator

Web carries the shear plus its share of moment (Iw/I); double web plates; bolt group polar analysis with eccentricity to the joint.

Standard: AS 4100 Cl 9.1.4, 9.3 · elastic polar bolt group

Inputs in the worked example

The live calculator starts with these values; change any of them and every result, check and diagram updates instantly.

Result	Value	Unit
Bolt diameter df	20.00	mm
Bolt tensile strength fuf	830.0	MPa
Tensile stress area As	245.0	mm²
Core area Ac (threads)	225.0	mm²
Shank area Ao	314.0	mm²
Plate yield stress fy (AS/NZS 3678)	280.0	MPa
Plate tensile strength fu	410.0	MPa
Web moment + shear eccentricity	72.75	kNm
Bolts	8.00
Σx²	9,800	mm²
Σy²	64,000	mm²
Polar Σ(x² + y²)	73,800	mm²
x max	35.00	mm
y max	120.0	mm
Corner bolt resultant	135.3	kN
Bolt capacity (double shear, web bearing fu 440)	185.3	kN
Plates shear 2·0.9·0.6 fy hp t	822.5	kN
Plates bending 2·0.9 fy t hp²/6	77.68	kNm

Diagram for the worked example

Bolt diameter df = CHOOSE(3,12,16,20,24,30,36) = 20 mm
Bolt tensile strength fuf = IF(2=1,400,830) = 830 MPa
Tensile stress area As = CHOOSE(3,84.3,157,245,353,561,817) = 245 mm²
Core area Ac (threads) = CHOOSE(3,76.2,144,225,324,519,759) = 225 mm²
Shank area Ao = CHOOSE(3,113,201,314,452,707,1018) = 314 mm²
Plate yield stress fy (AS/NZS 3678) = CHOOSE(1,IF(8<=8,280,IF(8<=12,260,250)),IF(8<=8,320,IF(8<=12,310,IF(8<=20,300,280))),IF(8<=12,360,IF(8<=20,350,340))) = 280 MPa
Plate tensile strength fu = CHOOSE(1,410,430,450) = 410 MPa
Web moment + shear eccentricity = 300*0.18+250*(40+(2-1)*70/2)/1000 = 72.75 kNm
Bolts = 4*2 = 8
Σx² = 4*70^2*(2-1)*2*(2+1)/12 = 9800 mm²
Σy² = 2*80^2*(4-1)*4*(4+1)/12 = 64000 mm²
Polar Σ(x² + y²) = 9800+64000 = 73800 mm²
x max = (2-1)*70/2 = 35 mm
y max = (4-1)*80/2 = 120 mm
Corner bolt resultant = SQRT((250/8+72.75*1000*35/73800)^2+(72.75*1000*120/73800)^2) = 135.34 kN
Bolt capacity (double shear, web bearing fu 440) = MIN(2*0.8*0.62*830*225/1000,0.9*3.2*20*9.1*440/1000) = 185.26 kN
Plates shear 2·0.9·0.6 fy hp t = 2*0.9*0.6*280*340*8/1000 = 822.53 kN
Plates bending 2·0.9 fy t hp²/6 = 2*0.9*280*8*340^2/6/1E6 = 77.683 kNm

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For preliminary design and education. Check every result against the current standard and your own engineering judgement before use.