BSI Standards Publication UK National Annex to Eurocode 3 Design of steel structures – Part 5 Piling NA+A1 2012 to BS EN 1993 5 2007 NA+A1 2012 to BS EN 1993 5 2007 NATIONAL ANNEX Publishing and copyr[.]
NA+A1:2012 to BS EN 1993-5:2007 BSI Standards Publication UK National Annex to Eurocode 3: Design of steel structures – Part 5: Piling NA+A1:2012 to BS EN 1993-5:2007 NATIONAL ANNEX Publishing and copyright information The BSI copyright notice displayed in this document indicates when the document was last issued © The British Standards Institution 2012 Published by BSI Standards Limited 2012 ISBN 978 580 78488 ICS 91.010.30; 91.080.10 The following BSI references relate to the work on this standard: Committee reference B/525/31 Draft for comment 08/30128156 DC, 12/30260809 DC Publication history First published July 2009 Amendments issued since publication Date Text affected July 2012 A1: see Introduction Summary of pages This document comprises a front cover, an inside front cover, pages to 8, an inside back cover and a back cover NATIONAL ANNEX NA+A1:2012 to BS EN 1993-5:2007 National Annex (informative) to BS EN 1993-5:2007, Eurocode 3: Design of steel structures – Part 5: Piling Introduction This National Annex is published by BSI Standards Limited, under licence from The British Standards Institution This National Annex has been prepared by BSI Subcommittee B/525/31, Structural use of steel In the UK it is to be used in conjunction with BS EN 1993‑5:2007 The start and finish of text introduced or altered by National Amendment No.1 is indicated in the text by tags Minor editorial changes are not tagged NA.1 Scope This National Annex gives: a) the UK decisions for the Nationally Determined Parameters described in the following subclauses of BS EN 1993-5:2007: —— 3.7 (1) —— 5.2.2 (13) —— 7.2.3 (2) —— 3.9 (1)P —— 5.2.5 (7) —— 7.4.2 (4) —— 4.4 (1) —— 5.5.4 (2) —— A.3.1 (3) —— 5.1.1 (4) —— 6.4 (3) —— B.5.4 (1) —— 5.2.2 (2) —— 7.1 (4) —— D.2.2 (5) b) the UK decisions on the status of BS EN 1993-5:2007 informative annexes; c) references to non-conflicting complementary information NA.2 Nationally Determined Parameters UK decisions for the Nationally Determined Parameters described in BS EN 1993-5:2007 are given in Table NA.1 NA.3 Decisions on the status of the informative annexes Informative annexes B, C and D may be used NA.4 References to non-contradictory complementary information The following references contain non-contradictory complementary information for use with BS EN 1993-5:2007 • PD 6695-5 • For further information on the durability of steel piles, see the Piling Handbook 8th edition [1] and the Corus brochure, A corrosion protection guide for steel bearing piles in temperate climates [2] © The British Standards Institution 2012 • NA+A1:2012 to BS EN 1993-5:2007 NATIONAL ANNEX • For additional information concerning ALWC, reference should be made to CIRIA document C634 [3] • Further information and guidance on the selection of values for bB is available from the Steel Piling Group website at www.steelpilinggroup.org • Further information and guidance on the selection of values for bD is available from the Steel Piling Group website at www.steelpilinggroup.org ã â The British Standards Institution 2012 Nationally Determined Parameter Minimum yield strength of high strength steel fy,spec,max Lowest service temperature Values for corrosion rates Subclause 3.7 (1) 3.9 (1)P 4.4 (1) BS EN 1993-5:2007, Table 4.1 and Table 4.2 0,00 0,15 0,20 0,18 0,50 Undisturbed natural soils (sand, silt, clay, schist…) Polluted natural soils and industrial sites Aggressive natural soils (swamp, marsh, peat…) Non-compacted and non-aggressive fills (clay, schist, sand, silt…) Non-compacted and aggressive fills (ashes, slag…) 2,00 0,70 1,00 0,75 0,30 25 years 3,25 1,20 1,75 1,50 0,60 50 years 4,50 1,70 2,50 2,25 0,90 75 years 5,75 2,20 3,25 3,00 1,20 100 years 7,00 2,70 4,00 3,75 1,50 125 years NOTE The values given for years and 25 years are based on measurements, whereas the other values are extrapolated NOTE Corrosion rates in compacted fills are lower than those in non-compacted ones In compacted fills the figures in the table should be divided by two years Required design working life Table 4.1 – Loss of thickness (mm) per face due to corrosion of bearing piles and sheet piles in soils, with or without groundwater Tables 4.1 and Table 4.2 are replaced by: −15 °C Use the recommended value 500 N/mm2 None UK decision Eurocode recommendation Table NA.1 UK decisions for Nationally Determined Parameters described in BS EN 1993-5:2007 NATIONAL ANNEX NA+A1:2012 to BS EN 1993-5:2007 â The British Standards Institution 2012 ã Subclause Nationally Determined Parameter Eurocode recommendation ã â The British Standards Institution 2012 0,15 0,30 0,55 0,25 Common fresh water (river, ship canal) in the zone of high attack (water line) Brackish or very polluted fresh water (sewage, industrial effluent…) in the zone of high attack (water line) Sea water in temperate climates in the high tide splash zone or in the low water zone (see Note 3) Sea water in temperate climates in the zone of permanent immersion or in the intertidal zone 0,90 1,90 1,30 0,55 25 years 1,75 3,75 2,30 0,90 50 years 2,60 5,60 3,30 1,15 75 years 3,50 7,50 4,30 1,40 100 years 4,40 Protection system required 5,30 1,65 125 years NOTE The values in this table for corrosion loss in the low water zone apply to situations where the effects of Accelerated Low Water Corrosion (ALWC) are not a design requirement ALWC is a particularly aggressive form of corrosion associated with bacterial activity at low water level in marine conditions Attack is random both within and between locations and typically at or just above the lowest astronomical tide (LAT) level Due to the high rate of steel loss when ALWC occurs, the life expectancy of a pile will be short and it is recommended that a protection system is used to control the situation rather than reliance on sacrificial steel Suitable options may be painting or cementitious coating but it is also recommended that consideration is given to installation of a cathodic protection system either immediately or at a later date if necessary Whilst this phenomenon might not affect every location, if ignored, this rapid form of attack can result in costly repair and maintenance works at an unexpectedly early stage in the life of a structure NOTE The values given for years and 25 years are based on measurements, whereas the other values are extrapolated NOTE The highest corrosion rate is usually found in the splash zone or at the low water level in tidal waters However, in most cases, the highest bending stresses occur in the permanent immersion zone (see BS EN 1993-5:2007, Figure 4-1) years Required design working life Table 4.2 – Loss of thickness (mm) per face due to corrosion of bearing piles and sheet piles in fresh water or seawater UK decision Table NA.1 UK decisions for Nationally Determined Parameters described in BS EN 1993-5:2007 (continued) NA+A1:2012 to BS EN 1993-5:2007 NATIONAL ANNEX Values of partial factors, cM0, cM1, and Values of factor bB for single and double U-piles Length l of continuous intermittent butt welds Value of factor bR Height of head h Value of factor bD Values of partial factors, cM2, and cM3,ser Value of factor kt 5.1.1 (4) 5.2.2 (2) 5.2.2 (13) 5.2.5 (7) 5.5.4 (2) 6.4 (3) 7.1 (4) 7.2.3 (2) 1,0 Limiting values for fu/fy and eu/ey Value of factor ηsys Required density or stiffness of tube filling A.3.1 (3) B.5.4 (1) D.2.2 (5) None fu/fy = 1,1 and eu/ey = 15 Design procedure for pile couplers None 0,6 cM2 = 1,25 and cM3,ser = 1,10 None 5 m 0,8 500 mm None Given in BS EN 1993-1-1 Eurocode recommendation 7.4.2 (4) cM2 Nationally Determined Parameter Subclause No additional information is provided Use the recommended value Given in NA to BS EN 1993-1-1 No design information additional to that already provided in BS EN 1993-1-8:2005, BS EN 1993-5:2007 and BS EN 12699:2001 is given for the design of pile couplers Only in cases where the structural detailing of the location where the anchor rod is joined to the wall is such that bending moments are avoided at that location, the recommended value for kt may be chosen as kt = 0,9 NOTE The recommended value for kt is kt = 0,6 This is motivated for cases where possible bending in the anchor as an effect of actions is not made explicit Use the recommended value Use the recommended values The recommended values for the factor bD applicable to UK designs are given in Table NA.2 Use the recommended value Use the recommended value Use the recommended value The recommended values for the factor bB applicable to UK designs are given in Table NA.2 Use values given in NA to BS EN 1993-1-1 UK decision Table NA.1 UK decisions for Nationally Determined Parameters described in BS EN 1993-5:2007 (continued) NATIONAL ANNEX NA+A1:2012 to BS EN 1993-5:2007 © The British Standards Institution 2012 • NA+A1:2012 to BS EN 1993-5:2007 NATIONAL ANNEX Table NA.2 Reduction factors for U shaped sheet piles Type of U-pile unit Number of structural support levels (see Note 1) Reduction factors bB and bD referred to in 5.2.2 (2); 5.2.2 (9); 5.2.3 (2); 6.4 (3) (see Notes 2, 3, 4, and 5) Highly unfavourable conditions Unfavourable conditions (see Note 6) (see Note 7) Favourable conditions (see Note 8) bB bD bB bD bB bD Singles or uncrimped doubles 0,40 0,30 0,50 0,35 0,60 0,40 0,55 0,35 0,60 0,40 0,70 0,45 >1 0,65 0,45 0,70 0,50 0,80 0,55 Crimped or welded doubles 0,70 0,60 0,75 0,65 0,80 0,70 0,80 0,70 0,85 0,75 0,95 0,80 >1 0,90 0,80 0,95 0,85 1,00 0,90 NOTE 1 Any restraint device which leads to the shear force changing from positive to negative or vice versa may be considered as a structural support The toe of the piles should not be considered as a restraint The benefit of the restraint should only be taken into account for design situations following installation of the restraint Restraints may be regarded as structural supports only when designed as such in accordance with relevant standards NOTE 2 If interlocks are not treated with sealants or lubricants, the coefficients may be increased by +0,05 (to a maximum value of 1,0) NOTE 3 The interlocks of single or uncrimped U-piles should be connected after installation by a structural weld (minimum mm fillet) near the top The minimum length of this weld should be 100 mm for walls with retained heights up to 2,5 m; for greater retained heights, an additional 100 mm of weld should be provided for every additional 1 m of retained height, up to a maximum of 500 mm (applies to retained heights above 6,5 m) Provision of this weld permits the bB coefficients to be increased by +0,1, 0,15 or 0,2 respectively for highly unfavourable, unfavourable and favourable conditions (to a maximum value of 1,0); and the bD coefficients likewise by +0,15, 0,2 or 0,25 (to a maximum value of 1,0) NOTE 4 The enhancement of b values by additional methods may be considered by the designer subject to demonstration, by calculation, testing or by other means, that the appropriate degree of shear force transmission will take place to justify higher coefficients than those values obtained from this table and notes NOTE 5 The bB and bD coefficients for the entire pile should be selected according to the most unfavourable conditions that apply NOTE 6 Highly unfavourable conditions are: • retaining substantial depths of free water; • significant presence of very low strength fine soil or very loose coarse soil (as defined in BS EN ISO 14688-1) below formation; • artificial loosening by pre-augering in fine soil below final excavation level (unless it can be demonstrated by testing or other means, that the pre-augered soil offers friction equivalent to or better than that of a low strength fine soil or loose coarse soil, in which case better conditions may be assumed); • artificial loosening of fine soil by water jetting at a rate exceeding 240 L/min (see Annex D.2 of BS EN 12063:1999); or • artificial loosening of coarse soil by water jetting at a rate exceeding 480 litres per minute (see Annex D.2 of BS EN 12063:1999) NOTE 7 Unfavourable conditions are: • significant presence of low strength fine soil or loose coarse soil (as defined in BS EN ISO 14688-1) below formation; • artificial loosening by pre-augering in coarse soil below final excavation level (unless it can be demonstrated by testing or other means, that the pre-augered soil offers friction equivalent to or better than that of a medium dense soil, in which case better conditions may be assumed); or • artificial loosening of fine soil by water jetting at a rate between 60 L/min and 240 L/min (see Annex D.2 of BS EN 12063:1999) or when coarse soil has been artificially loosened at a rate between 240 L/min and 480 L/min NOTE 8 Favourable conditions may be assumed if none of the highly unfavourable or unfavourable conditions apply ã â The British Standards Institution 2012 NATIONAL ANNEX NA+A1:2012 to BS EN 1993-5:2007 Bibliography Standards publications For dated references, only the edition cited applies For undated references, the latest edition of the referenced document (including any amendments) applies BS EN 1993-1-1, Eurocode 3 – Design of steel structures – Part 1-1: General rules and rules for building BS EN 1993-1-8:2005, Eurocode 3 – Design of steel structures – Part 1-8: Design of joints BS EN 12063:1999, Execution of special geotechnical work – Sheet pile walls BS EN 12699:2001, Execution of special geotechnical work – Displacement piles BS EN ISO 14688-1, Geotechnical investigation and testing – Identification and classification of soil – Part 1: Identification and description NA to BS EN 1993-1-1, UK National Annex to Eurocode 3 – Design of steel structures – Part 1-1: General rules and rules for building PD 6695-5, Background paper to the UK National Annex to BS EN 1993-5 1) Other publications [1] The Piling Handbook 8th edition, Arcelor www.sheet-piling.arcelor.com [2] Corus, A corrosion protection guide for steel bearing piles in temperate climates www.corusgroup.com [3] CIRIA document C634, Management of Accelerated Low Water Corrosion in Steel Maritime Structures www.ciria.org 1) In preparation © The British Standards Institution 2012 • NA+A1:2012 to BS EN 1993-5:2007 ã â The British Standards Institution 2012 NATIONAL ANNEX This page deliberately left blank This page deliberately left blank NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW British Standards Institution (BSI) BSI is the national body responsible for preparing British Standards and other standards-related publications, information and services BSI is incorporated by Royal Charter British Standards and other standardization products are published by BSI Standards Limited About us Revisions We bring together business, industry, government, consumers, innovators and others to shape their combined experience and expertise into standards -based solutions Our British Standards and other publications are updated by amendment or revision The knowledge embodied in our standards has been 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