Explained: Earthquake Resistance in Syria’s Construction Code
The Syrian Arab Code for the Design and Implementation of Reinforced Concrete Structures is a system for buildings to meet certain safety standards. Engineers and building contractors must adhere to this code during their study and design phases and when applying for their construction permits. The Syrian Engineers Syndicate (SES) and local administrative units oversee adherence to the code during the various stages of construction.
The SES adopted the first version of the code in 1992, later developing and issuing a second version in 1995 that included measures for earthquake-resistant buildings. The syndicate worked in this regard with the government institutions and entities responsible for developing the country’s seismic map to determine the earthquake-related factors that must be considered during construction, based on the American Standard Building Code UBC-85 (Uniform Building Codes of 1985).
In order to develop the conditions for earthquake resistance and keep up with international building codes, three appendices for Syria’s code were issued in 1996, 1997 and 2000. They included clarifications and conditions for designing earthquake-resistant buildings and evaluating existing structures and buildings, and rehabilitating them to be earthquake-resistant.
The third version of this code, which was issued in 2004, has a main section that includes articles on designing reinforced concrete structures and 14 appendices as an integral part of the code. Appendix 2, titled “Designing and Implementing Earthquake-Resistant Buildings and Structures”, was developed by a committee of the Engineers Syndicate, Syrian universities, the General Establishment for Geology and Mineral Resources and the Atomic Energy Commission of Syria.
In this appendix, there are four methods for designing earthquake-resistant structures depending on the nature and task of that structure. The first method, for small structures, is the simplest and relies on UBC-85. The second relies on UBC-97, which was simplified to comply with building materials and methods used in Syria. These first two methods are static and depend only on the impacts of earthquakes on the foundations of buildings. Meanwhile, the third method relies on response spectra dynamic analysis, that is, how the entire building structure responds to shaking during an earthquake. The fourth method uses temporal dynamic analysis, which considers an entire building structure’s response based on previous earthquakes.
For example, if a building is less than 73 metres high, it must comply with one of the two static methods. But if it is 73 metres or higher, one of the two dynamic study methods is mandatory, in addition to the necessary static method.
In 2013, the SES issued the second version of its earthquake appendix to prevent loss of life from building collapses and preserve the continuity of vital facilities. In this regard, the committee reviewed the first version. It made corrections, amendments and additions, relying on the International Building Code IBC-2009 and the ASCE-7 issued by the American Society of Civil Engineers.
The 2013 version of this appendix includes nine chapters and five sub-appendices. Chapters one and two clarify and explain specific terms and definitions. Chapter three concerns various design standards and loads, most notably a construction site’s geological features, seismology, soil characteristics, construction methods and earthquake impacts. Chapter four includes methods for calculating the force of earthquakes’ effects on buildings, while chapter five lists methods for dynamic analysis such as ground movements, static spectra and temporal analysis. Chapter six mentions the lateral forces that may impact construction and alternative design methods. Conditions for building design come in Chapter seven, which details the precautions that must be taken in construction design with regard to architectural design, structural design, and requirements for reinforcement, foundations and distance between buildings. Chapter eight discusses special structures with certain uses, such as retaining walls and tanks. Finally, Chapter nine discusses soil types.
The five appendices on earthquakes discuss (a) methods for affixing false ceilings, walls, glass fixtures and lighting, (b) seismic recording devices, (c ) how to calculate seismic load via static analysis, and (d) and (e) Syria’s seismic map and potential movement of the earth’s solid rock layer.