Comparison of the level of required prestressing of road bridges according to the historical development of technical standards in Slovakia

Abstract

The paper deals with the level of required prestressing designed for box-girder bridges. Mainly focuses on the development of standards used in the design of prestressed concrete road bridges in the Slovak Republic. The standards for bridge design have been amended several times. A parametric study was performed on a model post-tensioned concrete bridge with a box-girder cross-section. The bridge has three-span with a main span of 50 m and end spans of 40 m. The study compares the normal stresses caused by traffic load along the length of the bridge according to various standards and technical regulations. The differences in design principles were investigated while the amount and geometry of the longitudinal prestressing of the bridge were changed as required by corresponding standards. The numerical model is considered as a beam element with neglecting of the torsional effects of the load. The parametric study points out the differences in the normal stresses along the bridge according to different design regulations and standards. The aim of the study is to compare level of prestressing according to the historical development of prestressed bridges