Building standards, often called building codes, provide the first line of defense against potential earthquake damage and help to ensure safety in buildings designed and constructed in conformance with the codes. It is important to find out if the local building regulations provide for earthquake protection in the project location. If they do, then comply with the regulating provisions with respect to planning, design and construction, including typology of construction and quality materials for use in areas of seismic hazard.
Reviewing local building regulations is essential for setting the standards for planning, design and construction. Similarly, it is necessary to determine to what extent these regulations take into consideration the earthquake hazard in the region, and whether they provide sufficient protection. To do this, engage the local engineering community, especially those serving with the local government, in discussions. However, in regions where it is felt that local engineers’ capacities are low, consider consulting with external experts who understand the building standards needed in medium earthquake hazard zones.
Similarly, it is necessary to understand when these standards were last revised, and how often revisions occur. Earthquake information and engineering developments are rapid, and standards that have not been revised for more than five years may not meet requirements for project design. In such cases, more stringent design standards may have to be followed.
Many provisions in the building standards, if implemented, are intended to ensure that structures can adequately resist seismic forces during earthquakes. Building standards in some parts of the world are based on the required performance of a particular building in a future earthquake event. The performance levels could range from a building designed to prevent collapse in earthquakes, to a slightly improved ‘life safety’ (typically used for ordinary buildings), to ‘immediate occupancy’ where a building is designed to be usable minutes after an earthquake. It should be understood however, that the costs will increase substantially for higher performance levels. Hence, if such standards are in use in the project area, it is essential to understand and consider the performance required for each building in the project, and to set the building-performance goal needed for each. ‘Design Considerations’ provides further detail.
According to the building standards in some countries, the design will be influenced by how important the building is (depending upon the functional use of the building, the hazardous consequences of its failure, its post-earthquake functional needs, historical value, occupancy or economic importance). An Importance Factor (say 1.5) is multiplied in the calculations to provide additional earthquake resistance to buildings of greater significance. This however, is still an indirect approach. More direct and better approaches are also available for important facilities (see Design Considerations).
If the local building codes do not reflect the seismicity of the area, consider adopting and complying with building standards from other regions sharing similar geological conditions and earthquake hazards. In many countries, seismic hazard is not considered in building standards either because these are rare events or because the earthquake history is incomplete. However, it should be remembered that rare events can happen within the lifespan of the building and result in large losses.
The Importance of Building Codes in Earthquake-Prone Communities: http://www.fema.gov/media-library-data/1410554614185-e0da148255b25cd17a5510a80b0d9f48/Building%20Code%20Fact%20Sheet%20Revised%20August%202014.pdf