Július Šoltész*, Ivan Binder**, Milan Ecker***, Ľuboš Hruštinec*

Rehabilitation of the Ventilator Cooling Towers  in the Npp Bohunice in Slovakia Due to Increased Site Seismic Hazard

* STU Bratislava
** Binder-Projekting
*** Ecker projektová kancelária

The main objective of this report is to present the design concepts and methods of seismic retrofit used under the main reconstruction process  of NPP's  at Jaslovske Bohunice in Slovakia . All structures and corresponding technology units in the NPP undergone in last 10years a severe seismic evaluation, re-design and most of them was retrofitted.
The authors took part in the retrofit process of more than 20 industrial and special structures.

The report will concentrate on structural analysis and the final strengthening of the special industrial structure presented in the picture below. The analyzed system in a RC space frame without bracing system. (Response spectra analysis and time history analysis was used.) 17 strengthening models were analyzed. All possibilities (adding new shear walls into/onto the existing frames, adding steel elements, adding side-wing walls, strengthening with carboDurr plates, prestressing. The final solution is based on the combination of installation of steel bracing members, cut off the large mass RC members and replacing them with steel members.