The Code of Practice for the Structural Use of Steel (Limit State Approach), hereinafter referred to as “the Code”, gives recommendations for the design of structural steel buildings and allied structures not specifically covered by other standards. It does not cover all aspects of special types of steel structure such as rail or road bridges, articulated access walkways, nuclear power stations or pressure vessels. Nor does it cover structures made from fibre composites. The Code is not intended to be used for the design of bridges, which in Hong Kong would normally be designed to the Structures Design Manual for Highways and Railways and relevant codes. However, it may be used for the design of footbridges such as those connecting buildings. In such a case, reference should also be made to the Structures Design Manual for Highways and Railways and other acceptable references.
Section 1 contains general requirements including the scope of the Code.
Section 2 describes the principles of the limit state approach used in the Code.
Section 3 covers the use of hot rolled steel sections, flats, plates, hot finished and cold
formed structural hollow sections and cold formed open sections and sheet profiles conforming to acceptable international steel product standards from Australia, China, Japan, United States of America and United Kingdom versions of European Union standards (i.e. European standards with British National Application Documents). These standards are listed in Annex A1. In addition to covering normally available steel with yield stresses in the range from 190 N/mm2 to 460 N/mm2, this section gives design recommendations on the use of high strength steel, defined as steel with yield stresses between 460 and 690 N/mm2, and uncertified steel, whereby the design strength is limited to 170 N/mm2. The use of steels with yield strengths greater than 690N/mm2 is not covered in the Code. Where other structural materials are used in association with structural steelwork, they should conform to the Hong Kong or other equivalent standards. Particular examples are, but are not limited to, Concrete, Cement Grout, Reinforcement, Stainless Steel and Aluminium.
Section 4 gives design recommendations for partial load factors in normal and extreme
event load cases.
Section 5 contains particular requirements and guidance for deflection control and structural dynamics including serviceability criteria for wind induced oscillation of tall buildings. The section also covers durability and protection against corrosion attack.
Recommendations for the application of “second order” methods of global analysis are provided in Section 6.
Design recommendations in Sections 7, 8 and 9 cover the use of hot rolled steel sections, flats, plates, hot finished and cold formed structural hollow sections with steel grades up to yield stresses of 460 N/mm2 and allow use of yield stresses between 460N/mm2 and 690N/mm2 subject to restrictions.
Section 10 covers the design of steel and concrete elements acting compositely, with concrete up to a design cube strength of 60 N/mm2 and steel up to a design yield strength of 460 N/mm2. The use of lightweight concrete is not covered in the Code.
Section 11 provides simplified guidance on the use of thin walled cold-formed sections with a design yield strength up to 550 N/mm2.
Design recommendations for Structural Fire Engineering of steels up to yield stresses of 460 N/mm2 are given in Section 12.
Section 13 provides performance based design recommendations for various types of structure. These comprise high rise buildings, transmission towers, masts and chimneys, glass supporting structures, temporary works in construction, long span structures and footbridges. This section also contains guidance on loading from cranes and on maintenance of steel structures.
Sections 14 and 15 contain detailed guidance on fabrication and erection requirements. The procedures for loading tests given in Section 16 are intended only for steel structures within the scope of this Code.
Design recommendations for the evaluation and modification of existing steel structures are given in Section 17.
Annex A contains a list of the acceptable standards and references to the Building Authority for use in conjunction with the Code. Other standards or data in technical references may be used in lieu of the Code only if they can achieve a performance equivalent to the acceptable standards given in Annex A.
Annex B contains a method of calculating the relative strength coefficient for use in assessing the results of loading tests.
Annex C contains drawings of typical welding symbols.
Annex D contains testing to establish steel grades, essential requirements of product specifications for steel materials and bolts.

The Code of Practice for the Structural Use of Steel 2005 is hereafter referred to as the Code in these Explanatory Materials (EM).
Clause 1.1 of the Code points out the limitations of the scope of the Code, i.e. it does not cover special types of steel structure such as rail or road bridges, articulated access walkways, nuclear power stations or pressure vessels. These are all specialist areas and it is essential that the designers of such structures should use the particular relevant design codes and specialist literatures which are available. Naturally, the Code contains general principles of steel design which can be applied to the preliminary design of some special types of structure.
The Code notes that its sections on composite design do not cover structures made from fibre composites, such as carbon or glass fibre. The Code was drafted after a review of various national modern limit state codes, in particular those from Australia, China, Europe, Japan, United States of America and UK. It has adopted a similar approach to the style of the Australian and UK codes rather than Eurocodes or North American codes. However, it includes in one volume all those topics which are generally required for the design of building structures. In particular, it includes guidance on tall building design including appropriate comfort criteria, composite design of beams and columns, long span structures, stability issues including the use of second order analysis and a wide range of steel grades and qualities. It also includes more detailed specifications for materials and workmanship than many other codes. The Code addresses fundamental principles of overall stability, robustness, and the behaviour of the structure as a whole. It proposes an advanced philosophy and a number of methods for design against Strength, Ductility, Robustness and Stiffness under ultimate and serviceability limit states. Both manual and computer-based stability design methods are provided in the Code.
The Code contains 17 Sections and 4 Annexes in one volume in order to provide a concise single document containing guidance and requirements for the design of buildings and related structures.
Section 1 of the design requirements contains general requirements including the scope of the Code. Short clauses are provided on the overall design process and requirements for structures. Brief descriptions of limit state design philosophy, structural systems and integrity are included. These are expanded in subsequent sections of the Code. Hong Kong does not itself produce structural steel and the intention of the Code is to allow use of steels and steel materials, such as nuts and bolts, from the major worldwide suppliers on a “level playing field” basis. Section 3 covers the use of hot rolled steel sections, flats, plates, hot finished and cold formed structural hollow sections and cold formed sections conforming to acceptable national steel product standards from Australia, China, Japan, United States of America and United Kingdom versions of European Union standards. In addition to covering normally available steel with yield stresses in the range from 190 N/mm2 to 460 N/mm2, this section gives design recommendations on the use of high strength steel with yield stresses between 460 and 690 N/mm2, and uncertified steel, whereby the design strength is limited to 170 N/mm2. The use of steels with yield strengths greater than 690 N/mm2 is not covered in the Code.
Recommendations for the practical direct application of “second order” methods of global analysis are provided in Section 6. Design of slender structures including tall buildings is specifically considered in the Code. It recommends that for stability analysis, when a frame has an elastic critical load factor of less than 5, manual methods should not be used and a non linear second-order analysis, which includes consideration of P-Δ and P-δ effects and member and frame imperfections, should be adopted. This will take account of the second-order effect for sway and nonsway frames.