1、外文文献翻译 Protection,prevention,repair, renovation and upgrading （摘自 Management of Deteriorating Concrete StructuresChapter 7 作者 George Somerville ） 7.1 Introduction The need to repair concrete structure is not new. Much of the early work involved making good via patch repairs and crack filling, for ae
2、sthetic and serviceability reasons7.1. As the concrete infrastructure of the mid-20th century matured, there was also a demand to strengthen or upgrade to meet changes in use or increase in loadings. The need to treat cases of corrosion emerged in the 1950s with post-war prefabricated reinforced con
3、crete housing,and many of the references to Chapter 2 detail examples of corrosion in highway structures as the use of de-icing salts increased rapidly in the early 1960s.Reference7.2 gives some details of this ,and reference 7.3 is a detailed review of the situation in the UK and France with regard
4、 to post-tesioned concrete bridges. As durability concerns became more widespread, and consequences of failure more critical, repair became a growth industry, and options available on the market increased significantly in term of principles and approaches, and the individual solutions within each ba
5、sic approach. This taining over 200 short papers on all aspects of the problem. The literature is full of individual case studies, describing what has been physically done and giving some reasons for selecting a particular option； it is often diffcult to draw general conclusions from these. Such art
6、icles, which are also helpful since they provide website addressers,appear most frequently in concrete-related journals such as Concrete from the Concrete Society in the UK. In North America, the various journals of the American Concrete Institute (ACI) do a similar job, and focus on repair is provi
7、ded by the International Concrete Repair Institute (ICRI),which publishs a bimonthly Bulletin, and whose website gives details of available publications in the USA； generally, these are either guidance documents, or complications of articles on particular topics. There are aslo guidance documents av
8、ailable on individual repair, protection and upgrading methods, which explain the principles involved and are strong on the “how to ” aspects of the problem. Some examples of these can be obtained from the ICRI website for North America, and reference7.4-7.9 are similar publications available from t
9、he Concrete Society in the UK. The Concrete Society portfolio is augmented by other reports on test methods and diagnosis,and on how to enhance durability in new constructions； Technical Report 61 7.10 is an example of the latter, where much of the detailed information is transferable to the repair
10、and renovation situation. The Concrete RepairAssocication in the UK also has a website. The above brief rewiew is intended to show that there is quite a lot of information available on repair and renovation methods and also to indicate the nature of that information. It can become dated quite quickl
11、y however, as the technology is improved and new techniques are introduced. Moreover, the nature and format of the information make it difficult to compare the technical and economic merits of alternative approaches- essential information to the owner when making a choice. This situation is now chan
12、ging, with serious attempts being made to develop a systematic scientific basis for classifying repair and renovation methods, supported by sound specification and test methods. The emergence of EN 1504 is a prime example of that, and will be referred to strongly in later sections of this chapter. T
13、he final major missing link from the data bases is the lack of indepth feedback on real performation in the field over relevant periods of time. How does this compare with claims and expectations? Again this is changing, as typified by Figures 2.13-2.16 ,taken from the paper by Tilly 7.11. Tillys pa
14、per comes from the activities of a European network CONREPNET, which has examined well over 100 case studies in some detail and, apart from providing field data, has forced on developing criteria to permit alterative options to be evaluated to a common base. This information will also be used extens
15、ively later in this chapter. Repair and renovation is a huge subject, deserving several books in its own right.This book is about assessment, management and maintenance, and repair is an integral part of that. The emphasis in this chapter is on how it fits into the overall scheme of things, in movin
16、g forward from the assessment phase to taking effective action in selecting optimum solutions. This approach leads to the following sequence of subsection. 7.2 Performance requirements for repaired structures 7.3 Classification of protection, repair,renovation and upgrading options 7.4 Performance r
17、equirements for repair and remedial measures 7.5 Engineering specifications 7.6 Moving towards the selection process 7.7 Performance of repairs in sevice 7.8 Timing of an intervention 7.9 Selection a repair option-general 7.10 The role of EN 1504 in selection 7.11 Selecting a repair option in practi
18、ce 7.12 Concluding remarks Appendix 7.1 and 7.2 Reference 7.2 Performance requirements for repaired structures In simple terms, the performance requirements for repaired structures are no different from those for new construction. Structurally, the focus will be on the factors listed in Table 4.12.
19、Progressive assessment will have led to a performance time graph, such as that in Figure 3.13, for all relevant Table 4.12 factors. This paints a picture of how the present condition relates both to the performance levels provided in the original design and to the owners perception of what constitut
20、es minimum acceptable performance, bearing in mind that much more is now known about the structure (the Table 6.2 issue). Complicating the situation is the fact different owners may wish to manage the rehabilitation process differently. Figure 3.3 shows two viable options emanating from the asset ma
21、nagement procedures associated with bridge in the UK . The different strategies involved intervention on different timescales, and,most probably, different solutions. Some owners may also wish to take a conservative approach,involving early preventative measures. There are no definitive general rule
22、s here, but a need to be aware of what the options are , linked to confidence in their effectiveness. In moving forward, however, it is essential to be clear about the required performance levels. While the basic structural factors in Table 4.12 will remain, there are broader strategies issues invol
23、ved, some non-technical,which will influence the course which individual owners may choose to follow. Different owners will have different strategic goals, depending, for example, on: type of ownership whether private or public sector； changing statutory requirements； the type of structure and its f
24、unction； future plans for the structure, independent of its current physicall state, due, say, to a possible change in use； - improved performance requirements arising from higher user expectations； - increases in imposed loadings； a greater emphasis on whole life costing, linked to budgetary plans；
25、 s desire for improved sustainability. In a follow-up project to CONTECVET, a group of parters containing a high proportion of owners from Spain, Sweden and the UK, set out to establish a strategy for the maitenance and rehabilition of concrete structures. As part of this project, acronym REHABCON, a list of general performance requirements was developed. Table 7.1, taken from a REHABCON deliverable 7.12 ,gives
