Section 1 Introduction
Clasification Society 2024 - Version 9.40
Clasifications Register Guidance Information - Guidance Notes for the Classification of Special Service Craft – Version 1.0 Design Details, July 2013 - Chapter 3 Construction Tolerances and Defect Correction Procedures for Steel/Aluminium Construction - Section 1 Introduction

Section 1 Introduction

Parent topic: Chapter 3 Construction Tolerances and Defect Correction Procedures for Steel/Aluminium Construction

1.1 General

1.1.1 The fatigue life of structural details can be adversely affected by a variety of imperfections. The most common type of imperfections are:

  1. Misalignment of structural members, poor fit-up.

  2. Welding defects.

  3. Material defects.

  4. Poor manufacture and fabrication procedures resulting in stress concentrations.

  5. Unfairness of plating.

1.1.2 The actual influence on fatigue life will depend on the number, location and size of such imperfections.

1.1.3 Where design calculations highlight regions of stress concentration then experience clearly indicates that such regions will have a higher probability of failure during the life of the craft than surrounding structures. Hence in such locations there is a need to introduce standards that will reduce or eliminate the number or type of imperfections present.

1.1.4 Basic requirements concerning welding and structural details are given in Pt 6, Ch 2 Construction Procedures and Pt 7, Ch 2 Construction Procedures of the Rules for Special Service Craft for steel and aluminium alloy craft respectively. The individual standards employed by Builders are normally based on individual national standards, e.g. British Standards, and these supplement the Rule requirements.

1.1.5 Construction and erection criteria in accordance with such standards must inevitably be taken into account in the fatigue life calculation for any structural detail. Whilst it may be anticipated that such criteria may, in general, in association with an acceptable detail arrangement, provide for adequate fatigue life, there may well be instances where there is a specific need to introduce construction tolerances that are more rigorous.

1.1.6 The Clasifications Register Surveyors will be required to confirm that the work is carried out in accordance with the approved construction tolerances. Where the approved tolerances are exceeded then corrective action to the satisfaction of the Surveyor will be required. Details of the construction tolerances and defect correction procedures to be applied are indicated in Pt 3, Ch 1 General Regulations of the Rules for Special Service Craft.

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