Development of serviceability limit state design criteria for stresses in prestressed concrete girders

The objective of this paper is to perform the reliability analysis of stresses in prestressed concrete girders and development of design criteria for serviceability limit state design. Limit state functions for Serviceability Limit State (SLS) for compressive and tensile stresses at initial and service load stages are formulated based on fundamental design principles in the code. To establish statistical characteristics of concrete tension strength, two kinds of cylinder test, splitting tension tests and bending tension tests are performed for various specified strength of concrete. Other statistical characteristics for other variables such as live load, prestress forces, girder dimensions, and etc. are collected from related studies and references. Reliability indices are calculated for actually designed section and minimum section conformed with design requirement of typical prestressed concrete I-shaped girder and box type girder using first-order reliability method. Results are compared with reliability level of Ultimate Limit States (ULS) and target reliability indices of international standards. Finally, the live load factors in load combination for tensile stresses in prestressed concrete girder are proposed.