SOME ASPECTS REGARDING THE STRENGTHENING OF BUILDING STRUCTURES DAMAGED BY EARTHQUAKES

The construction works required to rehabilitate the buildings damaged by earthquake actions are extremely difficult since each structural system exhibits an unique damage pattern involving appropriate upgrading solutions and techniques. At the present time there is no unanimity of opinion among engineers as to the proper methodology for upgrading an existing building and little regulation or guidance on this subject has been produced. On the other hand, the rehabilitation of hazardous buildings to current design standards is generally very expensive. Apart from structural aspects, careful consideration to architectural, ornamental and functional aspects should also be given in many cases. Upgrading is an art as much as a science and engineering judgement is essential in selection of an appropriate solution. Since it is neither practical nor economically feasible to provide a damage resistant restored structure for all conceivable levels of earthquake motions, the definition of an acceptable level of building damage is of a paramount importance. Although lower factors of safety can be used in a seismic evaluation of an existing building and thus potential higher damage levels can be anticipated during severe earthquakes, the prevention of building collapse and preservation of life-safety should be the major objectives of the seismic rehabilitation. Further discussion considers the two design levels of seismic criteria, the Rumanian Seismic Design Code, and strengthening of masonry wall structures and masonry infilled frames damaged by earthquakes.