The structural framework design is the selection of the arrangement and sizes of the structural elements so that service loads may be safely carried. Structural designer has to complete the following steps to get a successful design:
- The general layout of structures,
- Studies of the possible structural forms that can be used,
- consideration of loading conditions,
- Analysis of stresses, deflections, etc.
- Design of parts,
- Design of assembly and connections, and
- preparation of design drawings.
The design procedure requires iterations and is repeated to incorporate the trail method:
- The functions to be preformed by the structure and the criteria for optimum solution of the resulting design must be established. This is referred to as the planning stage.
- The general layout of the structure is decided.
- Different arrangements of various elements to serve the functions in steps and considered. The possible structural forms that can be used are studied and an arrangement appearing to be best is selected for the first trail, called preliminary structural configuration. Only in very rare cases, it has to be revised later on.
- Loading condition are considered and the loads to be carried by the structure are estimated.
- Based on the decisions of earlier steps, trail selection of member sizes is carried out depending on thumb rules or assumed calculations to satisfy an objective criterion, such as least weight or cost.
- Structural analysis involving modeling the loads and structural framework to obtain internal forces stresses and deflections is carried out.
- All strength and serviceability requirements along with the predetermined criteria for optimum are checked. If any check is not satisfied, the member sizes are revised. This stage is called evaluation of the trail member sizes.
- Repetition of any part of the above sequence found necessary or desirable as a result of evaluation is performed in this stage called redesign.
- The rivets, bolts and welds along with other joining plates and elements are designed. The process is termed as the design of assembly and connections.
- It is determined whether or not an optimum design has been achieved, and the final decision is made.
- Drawings are prepared to show all design details. An estimate for the required quantities is also made. This stage of design is called preparation of design documents.
