First, a basic bent is designed for the project. The possibilities are endless. Criteria include the floor plan, spacing between timber trusses, design loads, and most importantly; an individual owner's aesthetic desires.

Loads are applied to the truss and a bending diagram is generated. The hammer beam truss shown to the left reacts as one would expect: Spreading forces are resolved by tension in the tie and braces. The tension is transferred to the hammer post and lower tie, then the lower braces goes into compression and a "kick" is taken by the column.

Often, this engineering step is done in 3D, so all the forces and reactions can be seen.

A 3D frame drawing is made in RISA (a great program for structural engineers) and balanced and unbalanced loads are applied. All the individual members go through a code check to make sure that none of them are over stressed. Beam sizes are modified for the loads, wind and shear forces are applied and the designer starts to think about engineering the connection details and forces on individual joints.

The diagonal trusses on the frame to the left spanned 60 feet. The common heavy timber and steel trusses spanned 48 feet.

Individual joints are sketched by hand and the forces and reactions are applied. Our engineer analyzes the joints for compression, tension, shear, bending, moment, etc., and solutions such as bearing required and the number of bolts and pegs are developed.