Standard revision to result in safer structures

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A major revision of the Standard for concrete design will be available soon, the result of which will be safer concrete structures and improved efficiency of design for structures using concrete. 

Dene Cook from the CCANZ and chair of the committee that developed the Standard, says a number of factors including the new loading Standard (NZS 1170.5:2004), new technical information and the need to provide a more user-friendly Standard, led to the revisions. 

In addition, recent updates of the Australian concrete Standard and of the American Concrete Institute Standard (ACI 318) contributed to the need for a revision of the 1995 version of the Standard. 

Engineering design knowledge is constantly evolving as a result of research undertaken in New Zealand and internationally, experience gained from evaluating the damage caused by major earthquakes around the world and the introduction of new materials such as steel fibre reinforcing. 

The Concrete Structures Standard includes the following essential information:

 • Minimum requirements for the design of reinforced and pre-stressed concrete structures, which is intended to provide a verification method for compliance with the New Zealand Building Code. 

A commentary, which:

• assists with understanding the requirements needed to comply with the Building Code, 

• provides guidance on test and design methods for steel fibre reinforced concrete, and • includes summary tables suitable as quick reference guides to the sections on beams, columns, walls and joints. 

Key updates to the Standard Several critical areas of the Standard have been updated: 

• The Standard includes new information on Grade 500 reinforcing steel. 

• The Design section is now component based as opposed to force based. 

• The Seismic Design section is now compatible with the recently released loading Standard NZS 1170.5:2004 Structural Design Actions. 

• Earthquake actions in New Zealand. 

• The Wall section reflects the latest developments in ACI 318 and testing conducted in New Zealand, including new formulas to address the potential issue of buckling of thin panel walls. • Fire section — the fire amendments to AS 3600:2001 Concrete Structures have been included. 

The Durability section now includes: 

• new information for structures with a specified lifespan of 100 years, 

• revised provisions for zone C marine exposure classifications, and 

• guidance on chemical exposure, aggressive soils, abrasion resistance and fastening protection. 

The appendices have been revised and include design information on strut and tie models (based on ACI 318) and provisions for the seismic design of ductile jointed pre-cast concrete structural systems.