CONSTRUCTION STAGE ANALYSIS OF SEGMENTAL BOX GIRDER BRIDGE

Abstract

Segmental bridge construction is very common in Pakistan. However, the impact of
structural system changes before and after the completion of segmental bridge construction is a
challenge and major concern for construction stakeholders. Therefore, in this study, construction stage
analysis was performed for balanced cantilever construction technique to check the safety and
serviceability of the bridge. Through time dependent analysis, considering the construction sequence
and creep deformation of concrete, structural responses related to the member forces were reviewed.
Moment reversal was observed in the cantilever segments near the face of the pier. Therefore,
maximum compressive and tensile stresses were observed in the top and bottom fibers of the girder,
respectively. These stresses were within the AASHTO LRFD limits for construction stage loads.
Results demonstrated that the creep moment redistribution started when the structural system changed
from statically determinate to indeterminate stage. Furthermore, it was concluded that the time
dependent deformation of concrete was the governing factor in order to achieve the final design
moments.