Interactive graphics tool for the calculation and serviceability limit state stress check of bonded post-tensioned concrete beams according to brazilian codes via Autodesk Robot Structural Analysis Professional(r)

This work presents an interactive graphics computational tool for the verification of prestressed concrete beams with post-tensioned bonded tendons to the serviceability limit state (SLS) stress check according to the Brazilian code NBR 6118:2014. The tool is an add-in for Autodesk Robot Structural Analysis Professional(r), which serves as a structural modeling platform. With data supplied by the user through a graphics user interface, the program here developed calculates all relevant prestress losses that occur throughout the structure's life-cycle, along with the prestress' equivalent loads during this period. The traditional calculation methods, obtained in the NBR 6118, are presented along with the modifications which had to be implemented in order to allow for incremental loss calculations. Usage examples and results are presented, validating the adopted methodology. At the end of the software's calculation, the user receives two outputs: the prestress' equivalent loads in the Robot model and an Excel spreadsheet. The spreadsheet contains the resultant stresses in the beam and warns whether these are greater than the permissible stresses in the SLS stress check. The loads may then be used in other calculations, such as shear reinforcement.