Case Study: Numerical Investigation of Lateral Stability of Non-prismatic Double Web-tapered Prestressed Reinforced Concrete Girder

Abstract

This study presents a comprehensive numerical investigation into the lateral stability of non-prismatic, double web-tapered prestressed reinforced concrete girders using advanced finite element modeling (FEM) in ATENA-GiD, validated against experimental results. The analysis examines the influence of key parameters, including initial lateral imperfections (ILI), rubber bearing pad stiffness, concrete tensile strength, load application method, and the effectiveness of fork support restraints. Results reveal that increasing ILI amplifies mid-span lateral displacement by up to 55%, compromising stability. Conversely, stiffer rubber pads improve restraint performance, reducing lateral displacement by 42%, while higher concrete tensile strength decreases lateral displacement by 32% and delays crack formation. Additional parametric studies highlight that the application of eccentric loads, common in experimental and real-world setups, induces secondary torsional effects that reduce lateral stability. A centric load application condition improved performance by reducing lateral displacement by 14%. Moreover, incorporating fully hardened fork supports at girder ends led to a 60% reduction in out-of-plane displacement, demonstrating their essential role in suppressing lateral-torsional buckling. These findings underscore the critical importance of accounting for geometric imperfections, support detailing, load positioning, and material properties in the design of slender, long-span, non-prismatic girders to ensure optimal stability and structural safety.