EFFECT OF PRESTRESSING ON CONCRETE BRIDGE COLUMNS

Prestressed reinforced concrete structural components are very commonly used in construction of civilian and military structures. The prestressed components, such as reinforced concrete columns, beams, and bridge decks, outperform the non-prestressed components because of the following reasons. A prestressed member has higher structural stifness and more load bearing capacity as well as better crack resistance compared to nonprestressed ones. This study focuses on efect of using prestressed cables in bridge piers. Diferent elements, such as the bridge height, prestressing loads, and compression capacity of concrete, are taken under investigation for a chosen sample case - \forg" bridge- located in south of Iran. To investigate the prestressed cables function in bridge piers with regard to aforementioned elements, the subject bridge is modeled in SAP software. After performing the spectral analysis, data for columns with and without the prestressed cables were collected. Acquired data were then analyzed using ABAQUS software. Results of this analysis show that prestressed concrete columns had less movement in all three axes (X, Y, and Z). Further studies also reveal that samples with prestressed cables had less damages compared to the non-prestressed ones. Studies also proved that increasing the prestressing load would result in less member displacements, less member defection, and also less stress in the section. These advantages are more efective in the direction of Y axis than the other axes. As for the efect of the structure height, samples from shorter columns tend to have minor damage and stress and, in general, better behavior in comparison to the samples from longer columns. In addition, concrete compressive strength plays an important role in prestressed members behavior; however, uncontrolled increase in concrete compressive strength could have a negative efect on the structure behavior.