ABSTRACT
This chapter is concerned with level 3 assessment in the action-module shown in Figure 4.1 (repeated for convenience as Figure 5.1). The objective is to develop a formal numerical approach to damage classification, as proposed in the CONTECVET Manuals [5.1]. However, as may be clearly seen from the figure, this should not be done in splendid isolation, without taking some account of structural implications; this is essential in providing a perspective, and as an aid to decision-making. The interpretation of data from inspections and selected tests is also
an important issue. Little has been said about that in Chapter 4, since, as indicated in Section 4.5.2, this is a specialist subject to be undertaken by experienced experts with detailed knowledge; however, some coverage is necessary here, in terms of the principles involved, with emphasis on assessing the structural implications alongside the formality of the selected damage classification method. Therefore, the sequence in this chapter is as follows:
5.2 Interpretation of test data 5.3 Engineering perspective in support of damage classification 5.4 Preliminary assessment; general principles and procedures 5.5 Preliminary assessment for ASR 5.6 Preliminary assessment for frost action 5.7 Preliminary assessment for corrosion 5.8 The nature and timing of intervention
References
5.2.1 Introduction
Aspects of this were dealt with in Sections 4.5 and 4.6, and this section will deal only with some basic principles, while creating an overall perspective. As indicated in Table 4.10, the range of available and relevant tests is large and varied, and interpretation requires experience and expertise. Guidance is available, and references that the author has found helpful include the following:
General guidance – References [5.2, 5.3, 5.4] ASR – References [5.1, 5.5, 5.6, 5.7] Frost action – Reference [5.8] Cracking – References [5.9, 5.10]
This represents a personal selection. There are numerous additional references, including most of those listed in Chapter 4. For most of the scientific tests in Table 4.10, particularly those that are
laboratory based, procedures are given in Standards on the methodology, with some guidance on the handling of the data and on precision. Generally, there is less certainty on what constitutes a critical result, in terms of its significance in the context of structural deterioration under less controlled site conditions. For many of the properties under investigation in the table, more than one test method is available – some simple and physical, others more technical – and, if resources and timescale permit, it is prudent not to rely solely on a single test method. Other tests give only an indirect measure of the property being inves-
tigated – e.g. the rebound hammer for concrete strength – and here the interpretation is especially important, in terms of both relevant and representative (the sampling issue). Any tests where moisture condition and micro-climate are significant parameters require special attention in interpretation, since these conditions can vary considerably both locally within the structure and seasonally over the structure’s life. Practical common sense and judgement are essential, together with a
standard and consistent approach, while attempting correlation, or even calibration, with results from similar investigations which appear in the literature.
