New developments of performance-based design codes and practice, honouring Prof. Yusuke Honjo

摘要

The concept of performance-based design codes arose in 2000s and has been gradually accepted in different parts of the world. In the language of Prof. Yusuke Honjo, Gifu University, Japan, who is one of the pioneers to establish this new concept in design codes, "performance-based design codes" typically comprise of a top-down hierarchical structure from the objectives of structures to performance and reliability requirements, and to standard means and verification protocols to achieve the performance requirements. There are mainly three backgrounds in the development of the performance-based design codes. Firstly, with an increase in public demand and industrial and academic motivations on the use of different technologies and materials, it becomes necessary more and more in many countries for the codes of practice to give guidance on the protocol of acceptance of alternatives. Accordingly, the codes of practice should have a structure of following design practice of thinking and working in terms of performance requirements for structures rather than descriptive specifications. For example, this leads to the hierarchical structure of codes from the objectives to the means, as represented by the TBT/WTO agreement and the Nordic Five Level System in trade. Secondly, it promotes an effective communication between the public/owner and the administration/designer in terms of the performance of structure for design situations. For example, this leads to the invention of performance matrix that was firstly introduced in SEAOC2000 in North America to ensure effective communication between the owner and the design regarding the seismic performance requirements. Thirdly, it is a generic concept that involves with prior design concepts of risk engineering, reliability engineering, and limit state design as tools to measure the required achievement level of the subject performance. For example, it is expected to harmonise existing descriptive regulatory and new developments while retaining or improving a uniform structural safety.