Foreword

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This document was prepared by Technical Committee ISO/TC 167, Steel and aluminium structures.

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Introduction

This document has been prepared to provide provisions and guidance in the testing of bolting assemblies for pretensioning for which no tightening parameters exist, e.g. when bolts are pretensioned by turning the head, for pretensioning of stainless steel bolting assemblies, when bolts need to be tightened in tapped holes or when a special lubrication is used. This document gives provisions and guidance on how to qualify those bolting assemblies for pretensioning and on how to determine secure tightening parameters.

1 Scope

This document specifies a test method to determine parameters of bolt tightening procedures for pretensioned bolted connections to be used in structural steelwork.

The methods to establish bolt tightening procedures given in this document are applicable to pretensioned bolted connections for which no approved tightening parameters exist in national or international standards. For example, in cases where bolting assemblies have to be tightened by turning the head instead of the nut, when conditions deviate from a given harmonized standard for pretensioning of bolting assemblies, or when stainless steel bolting assemblies are to be pretensioned. In these cases, tightening parameters as well as tightening procedures can be determined with the use of the Bolt Tightening Qualification Procedure (BTQP) given in this document.

2 Normative references

3 Terms and definitions

4 Symbols

5 General

6 Mechanical properties of bolting components

7 Fitness for purpose test

7.1 General

7.2 Test apparatus

7.3 Test assemblies

7.4 Test set-up

7.5 Test procedure

7.6 Evaluation of the test results

7.7 Requirements for suitability

7.8 Test report

8 Determination of tightening parameters

8.1 General

8.2 Criteria for the determination of the tightening parameters

Bibliography