Improving circularity of inverted T-girders

Abstract

Transitioning towards a more circular construction industry is crucial for achieving climate-neutral and fully circular operations by 2030. One significant contribution to this goal is fully utilising the reuse potential of prefabricated inverted T-girders. The primary challenge lies in adapting the inverted T-girder system to enhance the circularity of the girders. To address this, a comprehensive literature review is conducted to understand the structural response and disassembly challenges associated with the system, providing valuable insights into potential improvements. This study employs a numerical model based on the Finite Element Method using DIANA FEA to assess the impact of various design adjustments, specifically the removal of end transverse diaphragms and increasing deck slab thickness. The numerical model uses horizontal and vertical curved shell elements and is subjected to several critical load cases to determine the maximum stresses for different design parameters. The results indicate that eliminating the end transverse diaphragms has minimal impact on the distribution of longitudinal bending moments and shear forces. However, it causes a localised increase in support forces by 17\%. Additionally, significant differences are observed in the deck slab, necessitating an additional capacity of 16\% for transverse bending moments and 17\% for twisting moments. The study also examines the effect of skew angles to evaluate the applicability of orthogonal system findings to skewed systems. As the skew angle decreases, a greater proportion of forces and moments is absorbed by the deck slab rather than the composite girders. However, the mutual differences between systems with and without end transverse diaphragms generally vary by up to 2.6\%, indicating that the findings for the orthogonal system are broadly applicable to skewed systems as well.