Title 47 Welded Connections.pdf ✅

PSAD 42: Welded Connections Welded connections join two or more metals by melting the base material and adding a filler material to form a strong joint. In common welding processes, an electric arc is created between an electrode and the base metals to be welded. The heat generated by the arc melts the consumable core of the electrode, which acts as the filler material, and this molten material fuses with the base metals to create the welded joint. The common types of welds used are:  groove welds,  fillet welds, or  plug/slot welds 1. Fillet Welds Fillet welds are used to connect two adjacent members (perpendicular or at an angle to each other) along their edges. These welds are characterized by their triangular cross-section. 1.1 Effective Throat Capacity of fillet welds is based on the effective throat, which is the section on a weld formed by the shortest distance from the root to the face of the weld. Note, however, that weld size is defined by the length of the legs of the triangle formed by the fillet weld, not the effective throat thickness. For fillet welds with equal legs, the effective throat thickness is approximately 0.707 times the weld size.


2.3 Balanced Welds For unsymmetrical members, such as angles, their centroids are not at equal distances from the edges. Using a symmetric weld group to join unsymmetrical members will result into eccentricities. Therefore, weld lengths must be designed such that the group centroid coincides with the member centroid to minimize the resulting bending moment (a.k.a., balancing the welds). This is achieved by satisfying the zero-moment equilibrium equation, considering the applied force and the resistance from each weld in the group. The step-by-step procedure to check if a weld is balanced is as follows:  Step 1. Establish an equation for the top (or bottom) longitudinal weld force using summation of forces. Fଵ = P − Fଶ − Fଷ  Step 2. Establish an equation for the top (or bottom) longitudinal weld force using summation of moments about the bottom (or top) weld. Fଵ = Py௔ − Fଷ d 2 d  Step 3. Check if the equality Fଵ = Fଵ holds true. P − Fଶ − Fଷ = Py௔ − Fଷ d 2 d If allowable weld shear stress values are given, force values can be determined as follows: F௜ = F௩௪t௘L௜ 2.4 Eccentric Loading For cases where the applied load does not pass through the weld group centroid, additional effects from the resulting bending moment or torsional moment must be considered.