ISO 28841

Description / Abstract: This International Standard can be used as an alternative to the development of a building code, or equivalent document in countries where no national design codes are available by themselves, or as an alternative to the building code in countries where specifically considered and accepted by the national standards body or other appropriate regulatory organization, and applies to the assessment of earthquake resistance capability and to the seismic rehabilitation design and construction for existing structural concrete buildings.

The purpose of these guidelines is to provide sufficient information to perform the seismic assessment and rehabilitation of the structural concrete building that complies with the limitations established in Clause 5, for both undamaged structures that are deemed not to comply with the required characteristics for an adequate response at a specified performance level, and for structures that have undergone damage under seismic loadings. The rules of design as set forth in this International Standard are simplifications of more elaborate requirements.

Although the guidelines contained in this International Standard were drawn to produce, when properly employed, a reasonable assessment of the seismic vulnerability of an undamaged structure, a reasonable assessment of a structure damaged by a seismic event and a structural rehabilitation of the assessed concrete structure with an appropriate margin of safety, these guidelines are not a replacement for sound and experienced engineering. In order to attain the intended results on assessment and rehabilitation design, this International Standard must be used as a whole, and alternative procedures should be employed only when explicitly permitted by the guidelines. The minimum dimensioning guides as prescribed in this International Standard replace, in most cases, more elaborate procedures such as those prescribed in the national code or, if no national code exists, in internationally recognized full fledged codes, and the possible economic impact is compensated for by the simplicity of the procedures prescribed here.

The professional applying the procedures set forth by these guidelines should meet the legal requirements for structural designers in the country of adoption and have training and a minimum appropriate knowledge of structural mechanics, statics, strength of materials, structural analysis, and reinforced concrete design and construction.

While buildings rehabilitated in accordance with these guidelines are expected to perform within the selected performance levels for the applicable design earthquakes, compliance with these guidelines is necessary but may not guarantee the sought for performance, as current knowledge of structural behavior under seismic loads, and of the loads themselves, is still incomplete.