Fillet Weld Group Calculator to AS4100

This calculator allows the user to analyse and check each fillet weld within a weld group to ensure compliance with the Australian Standard AS 4100:2020. The user defines the weld group geometry by inputting the start and end coordinates of each weld line. Using user input forces, the calculator then checks the shear force at each end of each weld line to to ensure the critical design shear is considered.
A typical connection with a weld group is a beam to column welded connection.
❗This calculation has been written in accordance with Australian Standard AS 4100. 
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Beam to column welded connection
CalculationTechnical notes
This calculator does not consider out-of-plane forces.
This calculator checks for four weld lines only. For other amounts of weld lines, use the spreadsheet directly.
InputsWeld Properties
﻿﻿Weld category*
:1​
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*Input 1 for General Purpose (GP) or 2 for Special Purpose (SP)
﻿﻿Weld electrode type (E)
:69​
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﻿﻿Weld thickness
:6mm​
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Weld Group Geometry
Loads
OutputWeld Capacity
﻿﻿Capacity factor
:0.6​
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﻿﻿ fuw
:690MPa​
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﻿﻿Design capacity per unit length 
:1043N/mm​
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Weld Group Geometry
﻿﻿x coordinate of weld group centroid
:36.76mm​
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﻿﻿y coordinate of weld group centroid
:162.06mm​
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﻿﻿Polar second moment 
:16952667mm4​
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Loads
﻿﻿Resultant moment, M*o 
:24.0kN m​
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Design Check﻿﻿Weld group design check summary
:6mm GP 69 works​
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1​
63.24​
217.94​
354.81​
SAFE​
2​
-36.76​
217.94​
280.97​
SAFE​
3​
-36.76​
217.94​
280.97​
SAFE​
4​
-36.76​
-162.06​
289.58​
SAFE​
5​
63.24​
-162.06​
361.66​
SAFE​
6​
-36.76​
-162.06​
289.58​
SAFE​
7​
63.24​
-162.06​
361.66​
SAFE​
8​
163.24​
-162.06​
466.72​
SAFE​
ExplanationWelding is used in the fabrication of steelwork and is particularly useful in connections and for combining several plates or sections into built-up sections with greater capacity then available rolled sections. More then one weld line forms a weld group. A weld group is subject to in-plane eccentric forces and moments. 
Weld capacity
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The capacity of each weld line, ϕvw (N/mm) is:ϕvw=ϕ×0.6×tw/2×fuwwhere:tw is the weld thickness, andfuw is the nominal tensile strength of weld metal\text{The capacity of each weld line, } \phi v_w \text{ (N/mm) is:}\\ \phi v_w = \phi \times 0.6 \times t_w / \sqrt{2} \times f_{uw} \\ \text{where:} \\ t_w \text{ is the weld thickness, and} \\ f_{uw} \text{ is the nominal tensile strength of weld metal}  The capacity of each weld line, ϕvw​ (N/mm) is:ϕvw​=ϕ×0.6×tw​/2​×fuw​where:tw​ is the weld thickness, andfuw​ is the nominal tensile strength of weld metal
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Analysis of weld groups
To calculate the distribution of loads to each weld line in a weld group, the Instantaneous Centre of Rotation (ICR) Method is used. The ICR is the point at which the weld group rotates about when subject to overall weld group actions. The method follows the following steps:
The ICR (or centroid) of the weld group is evaluated based on the inputted weld group geometry.
All applied loads (F*x, F*y & M*z) are calculated as a concentrated resultant loads (F*x, F*y & M*o) at the ICR of the weld group.
The resultant loads are distributed to each weld line by calculating the shear force, v*w at the start and end of each weld line because the largest shear force for any given load on a weld line will occur at the ends. The v*w on each weld end is proportional to the distance from the weld end to the ICR. 
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The in-plane design force per unit length of weld, vw∗ (N/mm) is:vw∗=[vx∗]2+[vy∗]2where forces in the welds, per unit length, are:vx∗=Fx∗lw−Mo∗ysIwpvy∗=Fy∗lw+Mo∗xsIwpwhere xs and ys are the distances of a weld segment end from the centroid of the weld group, lw the total length of the weld group,Iwp the polar second moment of area of the weld group, andMo∗ the resolved in-plane moment about the weld group centroid, is:Mo∗=Mz∗−Fx∗ey+Fy∗ex\text{The in-plane design force per unit length of weld, } v^*_w \text { (N/mm) is:} \\v^*_{w} = \sqrt{[v^*_x]^2+[v^*_y]^2}\\ \text{where forces in the welds, per unit length, are:}\\ v^*_x = \frac{F^*_x}{l_w} - \frac{M^*_oy_s}{I_{wp}} \\ v^*_y = \frac{F^*_y}{l_w} + \frac{M^*_ox_s}{I_{wp}} \\ \text{where } x_s \text{ and } y_s \text{ are the distances of a weld segment end from the centroid of the weld group, } \\l_w \text{ the total length of the weld group,} \\ I_{wp} \text{ the polar second moment of area of the weld group, and} \\ M^*_o\text{ the resolved in-plane moment about the weld group centroid, is:}\\ M^*_o = M^*_z -F^*_x e_y + F^*_ye_xThe in-plane design force per unit length of weld, vw∗​ (N/mm) is:vw∗​=[vx∗​]2+[vy∗​]2​where forces in the welds, per unit length, are:vx∗​=lw​Fx∗​​−Iwp​Mo∗​ys​​vy∗​=lw​Fy∗​​+Iwp​Mo∗​xs​​where xs​ and ys​ are the distances of a weld segment end from the centroid of the weld group, lw​ the total length of the weld group,Iwp​ the polar second moment of area of the weld group, andMo∗​ the resolved in-plane moment about the weld group centroid, is:Mo∗​=Mz∗​−Fx∗​ey​+Fy∗​ex​
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Weld group loaded by in-plane actions: (a) initial in-plane actions, (b) resolved actions about centroid
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Weld category
Weld groups are categorised as either General Purpose (GP) or Special Purpose (SP). GP welds are typically used for static loaded or lower-stressed members and SP welds are selected for dynamic-loaded or higher-stressed members. 
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Weld electrode type
The electrode type defines the nominal tensile strength of the weld metal, fuw. 
The options of electrode types are:
E43
E49
E55
E62
E69
E76
E83
The fuw is simply the electrode type number x 10.
E.g. E69 has fuw = 690MPa
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Snippet from AS4100:2020
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1	63.24	217.94	354.81	SAFE
2	-36.76	217.94	280.97	SAFE
3	-36.76	217.94	280.97	SAFE
4	-36.76	-162.06	289.58	SAFE
5	63.24	-162.06	361.66	SAFE
6	-36.76	-162.06	289.58	SAFE
7	63.24	-162.06	361.66	SAFE
8	163.24	-162.06	466.72	SAFE