Preliminary Proportion Limits and Ultimate Strengths of Steel Box Girder Using Different Codes

— Steel Box Girder (SBG) bridges represent a widely used structural solution for both straight and curved bridges of moderate spans, owing to their high torsional rigidity, significant bending resistance, and rapid construction characteristics. This study provides a comprehensive theoretical comparison of the preliminary proportion limits, shear resistance design strength, and flexural resistance design strength in both positive (sagging) and negative (hogging) moment regions of SBG bridges. The comparison encompasses major bridge design specifications (BDS), including those of the American Association of State Highway and Transportation Officials (AASHTO), the Egyptian Code of Practice (ECP 207 – Part 6), and the European Standard Eurocode 3 (EC-3). The objective of this work is to develop a clear understanding of the design provisions, highlighting both similarities and differences among these internationally recognized standards. By analyzing the design criteria adopted in each code, the study aims to enhance familiarity with their respective requirements and ensure that the highest possible levels of structural efficiency and safety are achieved in the design of steel box girder bridges.