This report is the outcome of a rapid desk study to identify and collate the current state of evidence (in Nepal and other Low-Income Countries) to assess three issues:
(a) The regulation and effectiveness of seismic building codes in achieving the construction of safer and more liveable buildings, and in creating resilience against disasters.
Building codes are designed to create quality assurance and durability, with the objective to minimise economic loss due to material and structural deterioration, and to provide basic comfort and safety conditions. In earthquake-prone areas, building codes are complemented by seismic codes, specifying the calculation methods and strength values of key structural elements to avoid building collapse during an earthquake. In countries where building and seismic codes have not been implemented (Haiti, Pakistan, China, Nepal), large loss of life and economic set-back has occurred, compared to countries where seismic codes are strictly enforced (Peru, Chile, New Zealand and Japan) and the loss of life has been minimal. Furthermore, the extent of compliance or non-compliance of the seismic codes only becomes evident after a major earthquake event.
(b) The types of seismic building code systems used in different countries (ie. the strength requirements for private housing versus public buildings, such as schools, health facilities or industrial buildings), particularly in countries in the Himalayan region that are similar to Nepal with respect to risk and level of income.
Most seismic codes follow the American Concrete Institute (ACI) calculation methods (Nepal follows the Indian codes, which are similar to the ACI method). Earthquake zoning depends on the geographical conditions in the country. Not all low-income countries (LICs) are able to refine these data, thus requiring large safety margins. While there are no differences in building types, there are differences in the interpretation of the importance of building types (the i factor).
(c) What systems and mechanisms are used to ensure compliance in areas where seismic building codes are in place, and what examples are there of new technologies or innovative approaches to encourage compliance?
While seismic codes are often updated directly after the occurrence of a major earthquake with many casualties, new codes have little or no effect without an outreach or education system designed to create awareness about their content or when there is no enforcement system to strictly monitor their implementation.
In LICs, there is a large economic effort to upgrade the existing building stock in urban and rural areas, thus requiring tailored financing systems. The public administration is easily tempted to approve permits without any on-site building inspection, thus requiring enforcement of on-site building control to avoid corruption. In rural areas, most buildings are constructed without plans or calculations and realised progressively by village craftsmen and self-help methods, thus requiring code versions which are understandable by local craftsmen. Old code versions are as good as new versions for low-rise housing. When building inspectors are unavailable, community inspection methods have to be developed.
This report has been produced for Evidence on Demand with the assistance of the UK Department for International Development (DFID) contracted through the Climate, Environment, Infrastructure and Livelihoods Professional Evidence and Applied Knowledge Services (CEIL PEAKS) programme, jointly managed by DAI (which incorporates HTSPE Limited) and IMC Worldwide Limited.
Nienhuys, S. Seismic building codes: global and regional overview. Evidence on Demand, UK (2015) iv + 37 pp. [DOI: 10.12774/eod_hd.november2015.nienhuyss]