Committees responsible for this British Standard

The preparation of this British Standard was entrusted by the Cement, Gypsum, Aggregates and Quarry Products Standards Committee (CAB/-) to Technical Committee CAB/4, upon which the following bodies were represented:

Association of Lightweight Aggregate Manufacturers
Association of Metropolitan Authorities
British Aggregate Construction Materials Industries
British Civil Engineering Test Equipment Manufacturers’ Association
British Precast Concrete Federation
British Ready Mixed Concrete Association
Building Employers’ Confederation
Cement Admixtures Association
Cement and Concrete Association
Cement Makers’ Federation
Concrete Society
County Surveyors’ Society
Department of the Environment (Building Research Establishment)
Department of the Environment (Property Services Agency)
Department of Transport (Highways)
Department of Transport (Transport and Road Research Laboratory)
Electricity Supply Industry in England and Wales
Federation of Civil Engineering Contractors
Greater London Council
Institute of Concrete Technology
Institution of Civil Engineers
Institution of Highways and Transportation
Institution of Structural Engineers
Institution of Water Engineers and Scientists
Royal Institution of Chartered Surveyors
Sand and Gravel Association
Society of Chemical Industry

The following bodies were also represented in the drafting of the standard, through subcommittees and panels:

British Nuclear Fuels Limited
United Kingdom Atomic Energy Authority

This British Standard, having been prepared under the direction of the Cement, Gypsum, Aggregates and Quarry Products Standards Committee, was published under the authority of the Board of BSI and comes into effect on 31 October 1986

The following BSI references relate to the work on this standard:

Committee reference CAB/4
Draft for comment 85/14014 DC

Foreword

This Part of BS 1881 has been prepared under the direction of the Cement, Gypsum, Aggregates and Quarry Products Standards Committee. It supersedes BS 4408‑2:1969, which is withdrawn. All aspects of testing concrete are being included as Parts of BS 1881, from sampling fresh concrete to assessing concrete in structures. Part 201 gives general guidance on the choice of non-destructive test methods.

This Part describes several well-tried and accepted methods of measuring strain in concrete. There are other methods of measuring strain, some of which were described in BS 4408‑2. These include: semiconductor element electrical resistance; piezoresistance semiconductor; photoelastic gauges, fibre optics; micrometers, etc. While these methods may have special applications, they are not suitable for general use with concrete and so are not discussed in this standard.

There is a tendency for results obtained from a strain gauge to be accepted without question. The warning applies generally that it is often necessary to measure stress induced strains of the same order as those produced by changes in ambient temperature. Consideration should be given to the characteristics and limitations of the various devices and systems to ensure valid results.

A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application.

Compliance with a British Standard does not of itself confer immunity from legal obligations.

1 Scope

This Part of BS 1881 gives recommendations on methods and devices which can be used to determine strain in concrete. Some devices measure a property directly related to strain in the gauge (e.g. electrical resistance gauges) whereas others actually measure displacement, which can be used to determine strain using a known base length (e.g. displacement transducers). References to strain gauges in this Part include both types of device.

The use of the following devices is described:

mechanical (including mechanical/optical);
electrical resistance (metal and alloy elements);
vibrating wire (acoustic);
electrical displacement transducers.

NOTE The titles of the publications referred to in this standard are listed on the inside back cover.

2 Definitions

3 General guidance

4 Common types of strain gauge and their use

4.1 Mechanical gauges

4.2 Electrical resistance gauges (metal and alloy elements)

4.3 Vibrating wire (acoustic) gauges

4.4 Electrical displacement transducers

5 Choice of device

6 Report

Publications referred to

BS 1881-206:1986

Testing concrete - Recommendations for determination of strain in concrete

Current

Published:

31 Oct 1986