Upgrading the seismic performance of the interior water pipe supporting system of a cooling tower

This paper presents results from a numerical study that was performed in order to simulate the seismic behavior of the interior support system of the piping and cooling features of a cooling tower in one of the old power stations located in an area at the North-Western part of Greece. This cooling tower has a diameter of 60 m and a height of 100 m. The interior piping support system consists mainly of a series of nine-meter high pre-cast vertical columns made by pre-stressed concrete; these columns, together with reinforced concrete pre-cast horizontal beams that are joined monolithically with the columns at their top, form the old interior supporting system. This system represented a very flexible structure, a fact that was verified from a preliminary numerical analysis of its seismic behavior. The maximum response to the design earthquake levels resulted in large horizontal displacements at the top of the columns as well as overstress to some of the columns. The most important part of the current numerical investigation was to examine various strengthening schemes of the old interior support system and to select one that will demonstrate acceptable seismic behavior. (authors)