Advanced Structural Analysis/Part I - Theory/Loads

1.1. INTRODUCTION

The assessment of the loads that could be expected to act on a structure or elements of a structure is probably one of the significant aspects of structural design.

Two main loads

1. Permanent loads 2. Imposed loads

Imposed loads could be one of the following:

-Floor and roof -Wind -Cranes -Thermal -Geotechnical

Load calculations are usually the first to be determined in the actual design procedure for elements and the significance of determining the load intensities accurately cannot be emphasised enough.

All loading and load calculations will be based on the code of practice for the *Basis of structural design and actions for buildings and industrial structures.

The basis of design is "LIMIT STATES" which requires the characteristics loads to be amplified by partial load factors which vary depending on the nature of the applied load.

1.1.1. LOADING PATTERN

1.1.1.1. Uniformly Distributed A uniformly distributed load(UDL) is that which is constant over ant given length or area of a structure. The units are kN/m^2 (applied to slab) or kN/m (applied to beam).

1.1.1.2. Point Load

A point load is that applied by some intense load over a small enough area for it to be considered as acting at a point. The unit is kN.

1.1.1.3. Triangular or Trapezoidal Loss

These loads are common to beams supporting a two-way spanning slab. The units will be kN/m but the intensity of the load will vary along the length of the beam. The load from the slab is assumed to disperse at 45° from corners of the slab if the two edges of the slab meeting at the corner have the same support condition. This results in the beams sharing the load from the slab.