The Effect of Earthquake on Temporary Structures during Bridge Construction with Different Column Heights

This research aims to study the effect of earthquakes on temporary structures during bridge construction with different column heights for analysis and evaluation of the damage to temporary structures known as “Launching Gantry” and bridge structures. The primary focus is on temporary structures used in bridge construction with spans of 45 meters and heights of 7, 19, and 28 meters. The research examines four different stages of bridge construction: a single-span bridge, launching the gantry to install the next span, preparing to hang prestressed concrete box girders, and hanging the prestressed concrete box girders. The study uses 12 models created with the midas Civil computer program and nonlinear time history analysis to simulate seismic acceleration in the Bangkok area during the construction stage with a return period of 39 years to determine the internal force and the deformation. As a result, the forces were compared to the resistance according to Eurocode standards to evaluate the damage. The results show that the bridge structure is undamaged, with only minimal deformation, but significant damage was found in the legs of the supports, particularly the front support. The flexural moment and axial force were 1.53 times greater than the resistive strength, and the leg experienced deformation in the transverse direction of the bridge up to 71 millimeters, or 1/77 of the leg height.