Tuesday, August 13, 2019

Analyze and Design of the Prestress Concrete Girders

As a Structural Bridge Engineer, analyzing, design and review of prestress girders is part of my everyday assignments.

To make my life easy, I have made my own spreadsheets as well as finite element tools to complete above tasks.

Design or review, my approach is two way.

1.      Spreadsheet
2.      Finite Element Model - either using commercially available software Midas Civil, Bridge CSI or Stadd Pro

 I use my own spread sheets to perform preliminary design, initial assessment to great extent.

Figure 1 : My Spread sheet to analyze time dependent behavior of the PSC girder

Use of my own spreadsheet helps to strengthen my confidence on the task where I have so much control over the design I have undertaken.

Figure 2 : evaluating the stresses and Deflections using my own spread sheets

 Figure 3 : Magnel diagram for Simply supported PSC girder- Spreadsheet
Once I conducted my preliminary analysis, though it is very much closer to manual detail design, I review the design using a commercially available software. Midas Civil is a great software where it provides many features that a bridge designer required.

Figure 4 : Grillage Model for single span PSC girder

Figure 5 : 3D Model of the PSC Girder

Figure 6 : Result Interpretation and tendon Profile check

This two way approach has made my work tasks effective as well as efficient and made much complex tasks in to achievable miles stones.