Structural Analysis

Introduction

Any structure is designed keeping in mind its intended use, the materials available, cost and aesthetic considerations. The design of any project can be bifurcated into two parts:

i. The force determination at the member and the joints that can able to handle the load, force distribution to the adjutant member, etc.

ii. The selection of materials and designing the member in such a way that the stresses and deformations developed stay within permissible limits. 

Structural analysis is the fundamental possessions assessing the structural design under the specified loads, support conditions. It analyze the structural integrity of the structure under various circumstances such as applied vertical load , secondaty loads caused by primary loads, lateral loads, and seismic loads etc, to identify the feeble condition for select the member dimensions and the reinforcements in the project design. Once they are isolated, the design fallacies can then be worked upon, and corrected to develop a design that performs under anticipated conditions. In other words, the purpose of structural analysis is to keep the axial, torsional, shear, bending and any other internal forces of a project within permissible limits.

Scope of Structural Analysis

The structural analysis process can be broadly classified into three main categories:

1.     Static analysis: It determines the internal forces and displacements due to

time-independent loading conditions such as creep and shrinkages. 

2.     Stability analysis:It deals with project that are subject to compressed

time-independent forces.

3.     Vibration analysis: It determines the natural frequencies / eigenvalues

and corresponding mode shapes (Eigen functions) of vibration in the member.

Structural analysis of any project is based on the following assumptions:

1. The project material is completely elastic.

2. Superposition principle - any factor caused by different loads that act simultaneously are equal to the algebraic or geometric sum of this factor due to each load separately.

3. The deformation of the project caused by the applied loads do not change the original design diagram.

4. Relationship between stress and strain is linear.

Earlier, structural analysis was a tedious routine that involved solving mathematical equations manually. The introduction of CAE software has made structural analysis relatively simple, though it still takes a highly skilled engineer to properly interpret the results.