Truss Statics: Method of Joints (Tension vs. Compression)

A structural truss is an assemblage of straight members interconnected at pin joints. In ideal pin-jointed trusses, loads are applied exclusively at joints, meaning members experience purely axial forces: either axial Tension (stretching) or axial Compression (squeezing). Structural engineers solve for internal member forces using the Method of Joints, enforcing static equilibrium at every node: sum(F_x) = 0 and sum(F_y) = 0. While members in tension fail via tensile fracture, members in compression face catastrophic failure at much lower loads due to geometric buckling.