1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI British StandardsWB9423_BSI_StandardColCov_noK_AW:BSI FRONT COVERS 5/9/08 12:55 Page 1National Annex to Eurocode 1: Actions on structures Part 1-7: Accidental actionsNA to BS EN 1991-1-7:2006Licensed
2、 Copy: Wang Bin, ISO/EXCHANGE CHINA STANDARDS, 18/03/2009 01:40, Uncontrolled Copy, (c) BSINA to BS EN 1991-1-7:2006 BritiSh StANdArdPublishing and copyright informationthe BSi copyright notice displayed in this document indicates when the document was last issued. BSi 2008iSBN 978 0 580 65468 8iCS
3、91.010.30, 91.080.10, 93.040the following BSi references relate to the work on this standard: Committee reference B/525/1 draft for comment 07/30128330 dCPublication historyFirst published december 2008Amendments issued since publicationDate Text affected Licensed Copy: Wang Bin, ISO/EXCHANGE CHINA
4、STANDARDS, 18/03/2009 01:40, Uncontrolled Copy, (c) BSIBritiSh StANdArd BSI 2008 iNA to BS EN 1991-1-7:2006Contentsintroduction 1NA.1 Scope 1NA.2 Nationally determined Parameters 1NA.3 decision on the status of informative annexes 13NA.4 references to non-contradictory complementary information 14Li
5、st of tablestable NA.1 Equivalent static design forces due to vehicular impact on members supporting bridges over or adjacent to roads 3table NA.2 influence of class of road below bridge 4table NA.3 Minimum traffic flows to be used to determine F2 5table NA.4 influence of speed limit under bridge 5t
6、able NA.5 influence of junctions 6table NA.6 influence of clearance 6table NA.7 Number of columns for each support type 7table NA.8 deck stability 7table NA.9 Equivalent static design forces Fdxdue to impact on superstructures. 9table NA.10 Equivalent static design forces Fdydue to impact on superst
7、ructures. 9Summary of pagesthis document comprises a front cover, an inside front cover, pages i to ii, pages 1 to 14, an inside back cover and a back cover.Licensed Copy: Wang Bin, ISO/EXCHANGE CHINA STANDARDS, 18/03/2009 01:40, Uncontrolled Copy, (c) BSINA to BS EN 1991-1-7:2006ii BSI 2008BritiSh
8、StANdArdThis page deliberately left blankLicensed Copy: Wang Bin, ISO/EXCHANGE CHINA STANDARDS, 18/03/2009 01:40, Uncontrolled Copy, (c) BSIBritiSh StANdArd BSI 2008 1NA to BS EN 1991-1-7:2006National Annex (informative) to BS EN 1991-1-7:2006, Eurocode 1: Actions on structures Part 1-7: Accidental
9、actionsIntroductionthis National Annex has been prepared by BSi Subcommittee B/525/1, Actions (loadings) and basis of design. in the UK it is to be used in conjunction with BS EN 1991-1-7:2006.NOTE This National Annex refers to design values for accidental actions. In the UK National Annexes to BS E
10、N 1990:2002 Annex A1 and Annex A2, the safety factors for accidental actions are equal to 1. Therefore the nominal value and the design value for accidental actions are numerically the same. The nominal values and design values of an action are defined in BS EN 1990:2002 1.5.2.2 and 1.5.3.21 respect
11、ively.NA.1 Scopethis National Annex gives:the UK decisions for the Nationally determined Parameters a) described in the following subclauses of BS EN 1991-1-7:2006:2 (2) 4.3.2 (3) 4.6.1 (3)3.1 (2) 4.4 (1) 4.6.2 (1)3.2 (1) 4.5 (1) 4.6.2 (2)3.3 (2) 4.5.1.2 (1) 4.6.2 (3)3.4 (1) 4.5.1.4 (1) 4.6.2 (4)3.4
12、 (2) 4.5.1.4 (2) 4.6.3 (1)4.1 (1) 4.5.1.4 (3) 4.6.3 (3)4.3.1 (1) 4.5.1.4 (4) 4.6.3 (4)4.3.1 (2) 4.5.1.4 (5) 4.6.3 (5)4.3.1 (3) 4.5.1.5 (1) 5.3 (1)P4.3.2 (1) 4.5.2 (1) A.4 (1)4.3.2 (2) 4.5.2 (4)the UK decisions on the status of BS EN 1991-1-7:2006 informative b) annexes; andreferences to non-contradi
13、ctory complementary information. c) NA.2 Nationally Determined ParametersNA.2.1 Classification of accidental actions BS EN 1991-1-7:2006, 2 (2)All accidental actions are free actions unless otherwise stated in the individual project.NA.2.2 Notional values for identified accidental actions BS EN 1991
14、-1-7:2006, 3.1 (2) Note 4Values for accidental actions should be as given in BS EN 1991-1-7:2006 and this National Annex.Licensed Copy: Wang Bin, ISO/EXCHANGE CHINA STANDARDS, 18/03/2009 01:40, Uncontrolled Copy, (c) BSINA to BS EN 1991-1-7:20062 BSI 2008BritiSh StANdArdNA.2.3 Level of acceptable ri
15、sk BS EN 1991-1-7:2006, 3.2 (1) Note 3the level of acceptable risk should be determined on a project specific basis. recommendations for acceptable risk levels for road, footway and cycletrack bridges, are contained in Pd 6688-1-7.NA.2.4 Model of accidental action BS EN 1991-1-7:2006, 3.3 (2) Note 1
16、For building structures the recommended model should be used. NA.2.5 Acceptable limit of localised failure BS EN 1991-1-7:2006, 3.3 (2) Note 2For building structures, the indicative limits should be used. See A.4 of BS EN 1991-1-7:2006. NOTE In the Approved Document A to the Building Regulations 200
17、0 1 the area of floor at any storey cannot exceed 15% of the floor area of that storey or 70 m2, whichever is smaller, and does not extend further than the immediate adjacent storeys.NA.2.6 Design approach for limiting the extent of localized failure BS EN 1991-1-7:2006, 3.3 (2) Note 3For the design
18、 of building structures the three approaches given in 3.3 (2) of BS EN 1991-1-7:2006 may be used as appropriate and as specified in Annex A of BS EN 1991-1-7:2006. NA.2.7 Consequence classes BS EN 1991-1-7:2006, 3.4 (1) Note 4For the design of building structures the categorization given in table A.
19、1 of Annex A of BS EN 1991-1-7:2006 should be used.NA.2.8 Design approaches BS EN 1991-1-7:2006, 3.4 (2) NoteFor the design of structures for higher and lower consequence classes, the requirements should be determined for the individual project.NA.2.9 Accidental actions on lightweight structures BS
20、EN 1991-1-7:2006, 4.1 (1) Note 1recommendations for accidental actions on lightweight road structures are given in Pd 6688-1-7.NA.2.10 Impact forces to foundations BS EN 1991-1-7:2006, 4.1 (1) Note 3recommendations for transmission of impact forces to foundations are given in Pd 6688-1-7. Licensed C
21、opy: Wang Bin, ISO/EXCHANGE CHINA STANDARDS, 18/03/2009 01:40, Uncontrolled Copy, (c) BSIBritiSh StANdArd BSI 2008 3NA to BS EN 1991-1-7:2006NA.2.11 Values of vehicle impact forces BS EN 1991-1-7:2006, 4.3.1 (1) Note 1NA.2.11.1 Buildings adjacent to roadsFor buildings adjacent to roads, and in the a
22、bsence of mitigating measures, the indicative equivalent static design force due to vehicular impact given in table 4.1 of BS EN 1991-1-7:2006 may be used, unless the structure is in Consequence Class 3 (CC3). For CC3 buildings the equivalent static design force should be taken from table NA.1 and a
23、pplied in accordance with NA.2.11.2.2.1. Other sub-clauses from NA.2.11.2 are only applicable to road structures. the adjustment factor for buildings should be taken as 1.0.For buildings in CC1 and CC2 see also NA.2.13.NA.2.11.2 Bridges over roadsNA.2.11.2.1 IntroductionFor members supporting struct
24、ures over or adjacent to roads the equivalent static design forces due to vehicular impact should be in accordance with NA.2.11.2.2 to NA.2.11.2.4. Alternatively, where safety barriers are provided, recommendations are given in Pd 6688-1-7.table NA.1 Equivalent static design forces due to vehicular
25、impact on members supporting bridges over or adjacent to roadsForce Fdxin the direction of normal travelForce Fdyperpendicular to the direction of normal travelPoint of application on bridge supportkN kNBridges over Motorways, Trunk and Principal Roads Main component 1500 750 At the most severe poin
26、t between 0.75 m and 1.5 m above carriageway level residual component 750 375 At the most severe point between 1 m and 3 m above carriageway levelBridges over other roads where speed limit 45 mph (72 kph): e.g. Other Rural RoadsMain component 1125 565 At the most severe point between 0.75 m and 1.5
27、m above carriageway level residual component 565 265 At the most severe point between 1 m and 3 m above carriageway levelBridges over other roads where speed limit 26m 0,2Clearance C is measured from the centre of the nearest running lane ordinarily used by hGVs to the front face of the support. hen
28、ce, on a motorway, the hard shoulder is included in the clearance for supports adjacent to the left hand lane and, for supports in the central reservation, the right hand lane is included in the clearance if hGV travel is legally prohibited from that lane. Note that if a carriageway is only used in
29、maintenance situations or any part of the carriageway (for example the hard shoulder) is only opened to normal traffic for a specific period, such as at times of peak traffic flow, it should not be considered as a running lane for the purposes of calculating F5. the value of C should be determined b
30、y multiplying the horizontal distance in metres by 0,6 if the ground level at the face of the support is lower than the centre of the nearest running lane by more than 10% of the clearance, and by 1,6 if the ground level at the face of the support is higher than the centre of the nearest running lan
31、e by more than 10% of the clearance. Additionally, the value of C should also be determined by multiplying the horizontal distance by 0,6 if the support is alongside a road that has a gradient greater than 4% downhill and by 1,6 if the support is alongside a road that has a gradient greater than 4%
32、uphill. Licensed Copy: Wang Bin, ISO/EXCHANGE CHINA STANDARDS, 18/03/2009 01:40, Uncontrolled Copy, (c) BSIBritiSh StANdArd BSI 2008 7NA to BS EN 1991-1-7:2006NA.2.11.2.3.9 Factor for number of columns F6table NA.7 Number of columns for each support typeType of support F6Single columni) 2,0two colum
33、nsii) 1,5three columnsiii) 1,0Four or more columnsiv) 0,5risk of collapse of the bridge following partial failure of a support is significantly reduced if the number of columns provided is more than one (note that the use of longitudinally divided decks can increase the value of F6). Leaf piers (sup
34、ports that have a length along the carriageway similar to the width of the main structure above ignoring edge cantilevers) are to be treated as single columns. the relatively high value of F6for leaf piers will usually be counteracted by their relatively high impact resistance. NA.2.11.2.3.10 Factor
35、 for stability of deck F7table NA.8 Deck stabilityForm of Deck F7Continuous spans:i) With sufficient strength over the piers a) to prevent bridge collapse after impact: verified by quantitative assessmentWith sufficient strength over the piers b) to prevent bridge collapse after impact: assessment b
36、y engineering judgementWithout sufficient strength over the c) piers to prevent bridge collapse after impact1,0 1,52,0Simply supported spans, including spans iv) supported on cantilevers2,0NA.2.11.2.3.11 Consequence factor for road bridges F8F8= (1 200 + AAdtunder 0,006 + AAdtover 0,2)/6 300Values o
37、f AAdt should be calculated in a similar manner to that used in deriving F2. however, in this case AAdtoverincludes all traffic in the stream or streams that use the part of the bridge deck structure that might collapse following failure of the support, and AAdtunderalso includes all traffic in the
38、traffic stream or streams whose passage will be obstructed following the collapse. NOTE Where the bridge over can be split into separate decks for each carriageway, the AADToverover will be for one traffic stream. in cases where many pedestrians are expected to use the footway(s) at frequent interva
39、ls, for example for access to major public assembly facilities such as schools, sport stadiums, and public transportation facilities, the value of F8should be increased by adding a value of 5. Licensed Copy: Wang Bin, ISO/EXCHANGE CHINA STANDARDS, 18/03/2009 01:40, Uncontrolled Copy, (c) BSINA to BS
40、 EN 1991-1-7:20068 BSI 2008BritiSh StANdArdNA.2.11.2.4 Adjustment factor Fa for Table NA.1NA.2.11.2.4.1 the adjustment factor Fashould be applied to the values in table NA.1 for all classes of roads but should not be applied to the minimum robustness requirement. the threshold values, used to determ
41、ine whether the risk to the piers is high, normal or low, Taand Tbas described below are defined for the individual project. Unless otherwise specified for the individual project, the values for Taand Tbmay be taken as 2,4 and 0,5 respectively. NA.2.11.2.4.2 if the risk-ranking factor Rdeis greater
42、than Ta(i.e. the risk is high), the adjustment factor Fashould be taken as 2. NA.2.11.2.4.3 if the risk-ranking factor Rdeis less than or equal to Taand more than or equal to Tb(i.e. the risk is normal), the adjustment factor Fashould be taken as 1. NA.2.11.2.4.4 if the risk-ranking factor Rdeis les
43、s than Tb(i.e. the risk is low), the adjustment factor Fashould be taken as 0,5. NA.2.12 Impact force as a function of lateral distance s from traffic lanes BS EN 1991-1-7:2006, 4.3.1 (1) Note 2For buildings where the distance s of the centre-line of the nearest trafficked lane to the structural mem
44、ber is H10m, the equivalent static design force due to vehicle impact need not be considered. See also NA.2.13. For road bridges, the procedure described in NA 2.11.2.3 should be followed. NA.2.13 Structures for which vehicular collision need not be considered BS EN 1991-1-7:2006, 4.3.1 (1) Note 3Ve
45、hicle collision need not be considered for buildings in CC1 and CC2 provided that the design advice in BS EN 1991-17:2006 Annex A is applied. recommendations for ramps and stairs of footbridges are given in Pd 6688-1-7. Vehicle collisions for bridge supports need not be considered where, on the basi
46、s of judgement or experience, the structure is considered to have sufficient mass to withstand the effects of collision for global design purposes. NA.2.14 Rules for Fdxand FdyBS EN 1991-1-7:2006, 4.3.1 (2) Notethe recommended approach should be used. NA.2.15 Conditions of impact BS EN 1991-1-7:2006
47、, 4.3.1 (3) NoteFor buildings, except those in CC3, the recommended values should be used. For CC3 buildings and road bridges, the recommended values should be used for the application area. the point of application for impact forces on bridge supports is given in table NA.1. Licensed Copy: Wang Bin
48、, ISO/EXCHANGE CHINA STANDARDS, 18/03/2009 01:40, Uncontrolled Copy, (c) BSIBritiSh StANdArd BSI 2008 9NA to BS EN 1991-1-7:2006NA.2.16 Clearances and protection measures and design values BS EN 1991-1-7:2006, 4.3.2 (1) Note 1For buildings, where vehicle impact needs to be considered in the absence
49、of mitigating measures, the equivalent static design force due to vehicular impact given in table 4.2 of BS EN 1991-1-7:2006 may be used, unless the structure is in Consequences Class 3. For CC3 the equivalent static design force should be taken from table NA.9. For road bridges, the equivalent static design forces due to vehicular impact on the superstructure are given in table NA.9 and table NA.10.table NA.9 Equivalent static design fo
