In this section you will learn about:
|Methods||How did you perform the experiment/ investigation?||Descriptive writing|
|Materials||What did you use?||Descriptive writing|
|Rationale||Why did you select this method?||Critical writing in order to justify methods chosen|
Use descriptive writing to preview information in the methods section, particularly at the beginning of the chapter.
In order to understand the practical effects and behaviour of post-tensioning on concrete sections, computer models were created within the program MATLAB, which were able to predict the short-term and long-term behaviour of a variety of different cross-sections.
Later stages of the methods section give more detail about the methods and their underlying assumptions.
This model is applied under the following assumptions. The strain distributions on the cross-section, both immediately upon loading and after a prolonged period of sustained loading and shrinkage, are assumed to be linear. At any interval of time the change in curvature of the steel deck and concrete slab must be the same.
This preview has set the stage for even more detailed description and rationale, flagged by the section headings.
5.1.1 Cross-sectional Analysis
The cross-sectional analysis approach allows the governing equilibrium equations describing the behaviour of any cross-section to be expressed in terms of the two unknowns that define the strain diagram...
5.1.2 Short Term Analysis
The short term analysis of an uncracked reinforced or prestressed concrete cross- section at service loads is usually made assuming linear-elastic behaviour of the concrete (in compression and tension) and linear-elastic behaviour of the non-prestressed and prestressed reinforcement...
Specially designed materials can be described in stages using an overview such as a diagram or table followed by listing principal parts and finally a functional description.
Use critical comments about materials and methods to justify their selection.
The limitation of the age-adjusted modulus method is that it relies on a simple loading history of the concrete member. For a more accurate representation of concrete behaviour, a more refined method, such as the step-by-step procedure, may be required. Instead of just one time interval being considered, the step-by-step procedure involves the time interval being sub-divided into any number of sub-intervals based on the loading history. To calculate the structural response at time, the structural response at each time instant must be calculated in turn, as the solutions depend on the previous result.