scope:

Relationship to NZ Building Code

Minimum requirements

This Standard sets out minimum requirements for the design of reinforced and prestressed concrete structures. In addition to these requirements, every load or force acting on a structure shall have one or more dependable load paths that can transfer the force to the foundation soils. Each load path shall satisfy the fundamental structural design requirements of equilibrium and displacement compatibility.

This Standard does not cover the design of brittle elements. A brittle element is defined as a structural member that does not satisfy the minimum requirements specified in this Standard.

Non Specific Terms

Where this standard has provisions that are in non-specific or unquantified terms then these do not form part of the verification method for the New Zealand Building Code and the proposed details must be submitted to a building consent authority for approval as part of the building consent application. This includes but is not limited to where the standard calls for special studies, a rational analysis, for engineering judgement to be applied or where the Standard requires tests to be "suitable" or "appropriate". "Assessed" is used in code clauses where exact practical methods of calculation are not available but approximate methods are used to determine the likely order of an action.

Application to bridges

While this standard has been developed with the intent that it be generally applicable to the design of bridges, and is referenced by the Transit New Zealand Bridge Manual, some aspects are recognised to not be adequately covered by this Standard and designers are advised to make reference to appropriate specialised bridge design technical literature. Aspects of bridge design for which reference to the technical literature should be made include the following:

(a) Design for the combination of shear, torsion and warping in box girders;

(b) Design for deflection control taking into account the effects of creep, shrinkage and differential shrinkage and differential creep;

(c) Design for stress redistribution due to creep and shrinkage;

(d) Design for the effects of temperature change and differential temperature. (Refer to the Transit Bridge Manual for these design actions);

(e) Design for the effects of heat of hydration. This is particularly an issue where thick concrete elements are cast as second stage construction and their thermal movements are restrained by previous construction;

(f) Design for shear and local flexural effects, which may arise where out of plane moments are transmitted to web or slab members, or where the horizontal curvature of post-tensioned cables induces such actions;

(g) Seismic design of piers, where curvature ductility demand (material strain) exceeds the maximum permissible values in 2.6.1.3.

(h) Design for shear flow between flanges and webs in members.

Materials and workmanship requirements

It is applicable to structures and parts of structures constructed in accordance with the materials and workmanship requirements of NZS 3109.

Interpretation

"Shall" and "should"

In this Standard the word "shall" indicates a requirement that is to be adopted in order to comply with the Standard. The word "should" indicates practices which are advised or recommended.

Clause cross-references

Cross-references to other clauses or clause subdivisions within this Standard quote the number only, for example: "... is given by 8.6.2.3 (a)"

Commentary

The Commentary to this Standard, NZS 3101:Part 2:2006, does not contain requirements essential for compliance with this Standard but explains, summarises technical background and suggests approaches which satisfy the intent of the Standard.