Evaluation of structural behavior and cost of construction of a bridge designed by the segmentally constructed balanced cantilever method

The linguistic balanced cantilever construction method is the bridge construction method that has been used for years in the world and in our country and has many examples. The openings of which can reach 300 meters and the total distance of the viaduct can reach several kilometers, however, the middle openings are effective between 80-200 meters and are used as a primary construction method for box cross-section concrete slabs. The openings are moving to the middle of the opening to the right and left starting from the top of the column, in the form of a slice with certain lengths. The system operates as a balanced console. The bridge model becomes continuous after pouring the closing slice in the middle of the opening. As a result, two different stages should be taken into account in the design and project design of the viaduct made by the slice construction method. The primary purpose of this study is to compare the internal forces effects that occur with the design of the bridge as a continuous system, considering the construction stages of a bridge designed according to the sliced balanced console method. In addition, earthquake analysis of the continuous bridge system was also carried out. During this analysis, earthquakes were selected to examine the effect of distant and near faults. For this purpose, a balanced console with a total length of 345 m with 2 legs and 3 spans was designed and the analyzes were carried out on this bridge. The sample bridge model in this study was designed according to the application of Karşıyaka Viaduct in Trabzon, Ortahisar district, which is still under construction according to the precast beam bridge method. Thus, it was possible to perform comparative cost analysis of two different construction methods. In this study, the construction stages of the bridge superstructure are explained and the load and load combinations to be considered in the design are given. Necessary loads were calculated for the balanced console condition analysis of the viaduct superstructure. Bridge superstructure consists of slices with different geometry. For this reason, the time-stretching effects of each slice should be taken into account as the slices are applied at different concrete ages depending on the construction time. The bridge design regulation, which is internationally accepted and used by the General Directorate of Highways in our country, was analyzed by analyzing the material models of the slice-balanced cantile bridges in line with the provisions of the American Association of State Highway and Transportation Officials (AASHTO). Accordingly, in this master's study, the production stages of the slices were first examined according to the incremental time-step analysis method and the stresses that occurred after the completion of each slice in each section were analyzed. It has been determined that the stresses formed in any section during the construction phase time do not exceed the allowable stress limits set in AASHTO. Again, the balanced cantilever bridge model was analyzed in Düzce 1999 Earthquake records in the time domain. As a result of the analysis, it was found that the bending moment values in the model gave higher results in earthquake suspicion. As a result of the analysis made according to the construction stage, higher bending moment, shear force and tensile values were obtained. From this point of view, the necessity of making the bridge designs not only according to the service status but also the construction stages has been revealed. The results obtained especially in the calculations of the ropes can affect the amount of ropes. In our country, which is in the active fault zone, rope insufficiency may cause serious problems. There are many bridge class methods used in our country and in the world. The most commonly used bridge class is the precast beam bridge. As a result of the comparative cost analysis conducted with the Karşıyaka Viaduct under construction, it was found that the cost of the sectional cantilege bridge, which is the subject of this study, is up to 33% lower.