Evolution and present updation of ‘Code for seismic design of buildings’

A general review of development and evolution of seismic design codes in China is provided in the paper.Major features contained in several versions and the present update of 'Code for seismic design of buildings’ are summarized.Main items regarding to earthquake levels,design earthquake acceleration,essential requirements of seismic design,site assessment and classification,seismic response spectra,seismic alalysis as well as regulations of seismic calculations and detailing for each type of structures,including spacious and underground buildings have been seriously revised in the past.The revision of the Code TJ 11—78 was timely executed based on the investigation on damages and collapses of different buildings caused in the 1976 Tangshan Earthquake.Buildings and infrastructures were put into the real tests in the May 12,2008 Great Wenchuan Earthquake,revealing that the three seismic goals in terms of operational under the minor earthquake,repairable under the moderate earthquake and life-safety under the major earthquake can be achieved as long as the design and construction following the code requirements.Building damages and failures,of course,occurred unavoidably due to the much higher intensity than expected by design code.Based on extensive reconnaissance investigation of building damage in the regions with moderate to severe earthquake intensities,regulations of the 'Code for seismic design of buildings’(GB 50011—2001) are updated regarding to the multi-fortification,strong column-weak beam,link beam of shear walls,integration and ductility of masonry structures,exit ways and stair shaft,non-structural elements,etc.The concept of performance-based seismic design has been implemented in the new version of the code that improves and enriches the seismic design approach of so-called two stages for three earthquake levels.