maximum test load Anchor head displacement under maintained load

There is extensive guidance, which was debated at length during drafting of EN 1537,9 on corrosion protection of steel tendons and stressed steel components, including discussion of common components and materials for corrosion protection barriers such as plastic sheaths and ducts, heat shrink sleeves, seals, cement grout, and resins.

EN 1537 provides far more design guidance than other execution standards, including a method for designing ground anchors which is discussed in Chapter 14. Work is already underway within CEN's Technical Committees TC 250/SC7 and TC 288 to move this design guidance from EN 1537 to Eurocode 7. The specification of the various anchor tests is also likely to be moved (into EN 22477-5), leaving EN 1537 to concentrate on matters relating solely to execution.

The national foreword to BS EN 1537 states that it supersedes those parts of BS 8081:198910 that deal with the construction of ground anchorages. BS 8081 is currently being revised in order to remove this conflicting material.

EN 1537 was published by CEN in 1999, confirmed in 2005 for two years, and scheduled in 2007 for revision by TC 288 following a systematic review. A corrigendum was issued in 2000.

15.3.4 Reinforced fill

Figure 15.9 summarizes the scope of EN 14475,11 which deals with the execution of reinforced fill.

The standard provides a review of various facing systems, including: partialand full-height facing panels; sloping panels; planter units; segmental concrete blocks; king post systems; semi-elliptical steel faces; steel wire grids; gabion baskets; wrap-arounds (with or without formwork and bagged); and in situ concrete facings. For each facing system, the standard reviews its main application; any reinforcement needed; the technology involved; its longitudinal and transverse flexibility; fill material; and tolerances in alignment, differential settlement, and compressibility.

EN 14475 helpfully details the design output necessary for reinforced fills. This includes things such as drainage, construction phases, level of control, frost susceptibility, type and configuration of reinforcement, steel grade and type of coating, geosynthetic creep behaviour, aesthetic requirements, top soils for greened faces, and a further twenty or so topics not listed here.

The foreword to EN 144475 clarifies its relationship with Eurocode 7:

'Eurocode 7... does not currently cover the detailed design of reinforced fill structures. The values of partial factors and load factors given in EN 1997-1 have not been calibrated for [them].

... a two stage approach has been adopted ... first producing an EN giving guidance on the Execution of reinforced fill, before working towards a common method of design. This standard represents the implementation of the first part ...'12

The national foreword to BS EN 144475 further clarifies its relationship with BS 8006:13

'This [standard] partially supersedes BS 8006:1995 which is currently being revised in order to remove conflicting material. In the meantime, where conflict arises between the two documents the provisions of BS EN 14475 should take precedence'14

0 0

Post a comment