WeldCalcs app for iPhone and iPad

Useful for the preliminary sizing of fillet welds, WeldCalcs is an engineering calculator app that computes the section properties for typical welding patterns used in steel construction. After selecting a Weld Group, the user enters the dimensions for the depth and width, along with any combination of applied forces and moments. The section properties for the Weld Group, including the area, section moduli and polar moment of inertia, are instantly calculated. The app also determines the maximum resisting resultant force and the initial fillet weld size.

The calculations performed by the WeldCalcs app are based on the Elastic Method. This approach treats the weld as a line or a group of lines. This allows the weld group section properties to be determined without knowing the size of the weld. The section properties and the applied loads are used in structural engineering formulas to determine the maximum resisting resultant force along the weld. This resultant force is expressed in terms of force per unit length.

Since the weld is evaluated based on a force per unit length, in lieu of stresses, combining the effects from different load types (shear, axial, moment, torsion) is easily accomplished. The applied moments and torsions are resolved into vertical, horizontal and axial components and then vectorially combined with the directly applied shears and axial forces. All of the applied loads are assumed to act through the center of gravity of the weld. Therefore, each segment of the weld resists an equal share of the direct shear and axial forces and a proportional share of the bending moments and torsions relative to the weld segments distance to the neutral axis of the weld group.

The fillet weld size is determined by dividing the maximum resisting resultant force by the available strength of the weld. For practicality, both weld dimensions d and b are limited to a minimum value of 0.25 inches and a maximum value of 100 inches. Dimensions tw and tf are limited to a minimum value of 0.125 inches and a maximum value of 10 inches. The applied forces are limited to a range of -99,999 to +99,999 kips. The applied moments are limited to a range of -99,999 to +99,999 kip-inches. The equations for the section properties and resultant forces used by the app are available for reference and manual verification by the user. The general equations for the resisting forces in each quadrant are based on the applied forces and moments all acting in the positive direction.