Principles of Influence Line Analysis

In Principles of Influence Line Analysis, you'll learn ...

• What influence lines represent, their importance, and their application in practice
• How to construct influence lines
• How to verify the solution of an influence line from a computer analysis

Overview

Credit: 4 PDH

Length: 83 pages

Influence line analysis is an efficient analytical method used in bridge and building design to determine governing responses in a structure that is affected by moving loads. Many engineers familiar with this type of analysis may consider influence line calculations to be labor-intensive, complicated, and time-consuming. This may lead some to bypass this step in the design process. Some of the most experienced engineers who decide to forgo this type of analysis may indeed be able to determine most critical load effects by inspection within a certain degree of precision. In doing so, vital information revealing the most severe loading configurations in the structure may be lost. This type of situation may lead to unchecked loading conditions and opens up opportunities for questioning.

Commercial structural analysis software facilitates the effort required to generate influence lines and response envelopes. While many rely on these computer programs on a regular basis, sometimes the user of such a program may be questioned in detail about the output by either a customer or an auditor. Standardized influence coefficients are published in specialized literature for specific continuous beam arrangements, but oftentimes these values are unsuitable for use. For these reasons, it is beneficial to have the resources to independently check a computer solution.

How can one be confident that the worst-case scenario loading is checked? This course addresses this question by first addressing fundamental analysis concepts. This is followed by several detailed example problems with each illustrating a step-by-step solution procedure, including a practical design example. Some examples covered in this course utilize powerful solving methods found in Microsoft Excel.

This course may serve as a refresher of basic analysis skills, but also covers topics in advanced analysis. In that regard, having a background in matrix algebra is helpful for this course. This course is intended for practicing civil engineers and structural engineers and can even serve as a general resource for applied structural analysis in its own right.