Introduction to Structural Engineering

Overview

A structure is an assemblage of components which are connected in such a way that the structure can withstand the action of loads that are applied to it. These loads may be due to gravity, wind, ground shaking, impact, temperature, or other environmental sources. Examples of structures employed in civil infrastructure are buildings, bridges, dams, tunnels, storage tanks, and transmission line towers. Non-civil applications include aerospace structures such as airplane fuselages, missiles; naval structures such as ships, offshore platforms; and automotive structures such as cars and trucks. Structural engineering is the discipline which is concerned with identifying the loads that a structure may experience over its expected life, determining a suitable arrangement of structural members, selecting the material and dimensions of the members, defining the assembly process, and lastly monitoring the structure as it is being assembled and possibly also over its life.

In this chapter, we describe first the various types of structures. Each structure is categorized according to its particular function and the configuration of its components. We then discuss the critical issues that a structural Engineer needs to address when designing or assessing the adequacy of a structure. The most important issue is preventing failure, especially a sudden catastrophic failure. We describe various modes of failures: initial instability, material failure, and buckling of individual structural components. In order to carry out a structural design, one needs to specify the loading which is also a critical concern. Fortunately, the technical literature contains considerable information about loadings. We present here an overview of the nature of the different loads and establish their relative importance for the most common civil structures. Conventional structural design philosophy and the different approaches for implementing this design strategy are described next. Lastly we briefly discuss some basic analytical methods of structural engineering and describe how they are applied to analyze structures.