This is a web-app that analyzes precast prestressed stadium riser sections, which are not symmetrical about their vertical axis, contrary to most precast concrete elements. Once the user inputs all necessary information and clicks the 'Analyze' button, the app:
The dimensions which should be input in the boxes are shown in the figures. Other input parameters are:
Please use . not , for decimal points
Principal axes are the set of axes, not necessarily axes of symmetry, for which the second moment of area is zero. It is necessary to determine the principal axes and their orientation with the horizontal axis to analyze unsymmetric sections.
At this section, stresses at extreme points at mid-span are calculated for positive sway and negative sway. These stresses are checked to stay within limits of allowable compressive and tensile stresses that are given below. If the stresses exceed these limits, the user is warned by way of red colored output boxes and either the member dimensions or the prestressing design of the member should be changed to satisfy stress requirements.
At this section, flexural strength of the section is determined iteratively (Secant Method) for flexure about X'-X' and Y'-Y' axes. Figure below shows the following parameters at section equilibrium: