Integrating system reliability and optimization in prestressed concrete design

In this paper, second moment reliability method for components and systems are integrated with optimization tools in the design of prestressed concrete (PC) beams. Loading, material properties, prestressing force levels, as well as the models used to predict flexural behavior are all treated as random variables. The performance functions considered are related to the stresses at initial and final stages as well as the flexural strength of the beam. System reliability methods are used to compute the probabilities of unsatisfactory performance of PC beams at these limit states. Reliability-based design examples of double-tee PC beams commonly used in the construction industry are presented in design-chart formats.