NA to BS EN 1991-2:2003:2008 Edition
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UK National Annex to Eurocode 1. Actions on structures – Traffic loads on bridges
Published By | Publication Date | Number of Pages |
BSI | 2008 | 52 |
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3 | Contents Introduction 1 NA.1 Scope 1 NA.2 Nationally determined parameters 2 NA.3 Decision on the status of informative annexes 45 NA.4 References to non-contradictory complementary information 46 Bibliography 47 Figure NA.1 – Basic longitudinal configuration of SV model vehicles 5 Figure NA.2 – Basic longitudinal configuration of SOV model vehicles 7 Figure NA.3 – Lateral wheel arrangement for trailer axles of all SOV models 9 Figure NA.4 – Typical application of SV or SOV and Load Model 1 loading when the SV or SOV vehicle lies fully within a notional lane 11 Figure NA.5 – Typical application of SV or SOV and Load Model 1 loading when the SV or SOV vehicle straddles two adjacent lanes 11 Figure NA.6 – Vehicle model for abutments and wing walls 22 Figure NA.7 – Effective span calculation 27 Figure NA.8 – Relationships between k(fv) and mode frequencies fv 27 Figure NA.9 – Reduction factor, *, to allow for the unsynchronized combination of pedestrian actions within groups and crowds 28 Figure NA.10 – Response modifiers 31 Figure NA.11 – Lateral lock-in stability boundaries 33 Figure NA.12 – Flow chart for determining whether a dynamic analysis is necessary for “simple” structures 36 Figure NA.13 – Flow chart for determining whether a dynamic analysis is required for “simple” and “complex” structures 38 Figure NA.14 – Limits of bridge natural frequency nO in [Hz] as a function of L in m 40 List of tables Table NA.1 – Adjustment factors !Q and !q for Load Model 1 4 Table NA.2 – Dynamic Amplification Factors for the SV and SOV vehicles 9 Table NA.3 – Assessment of groups of traffic loads (characteristic values of the multi-component action) 14 Table NA.4 – Indicative numbers of heavy goods vehicles expected per year and per lane in the United Kingdom 16 Table NA.5 – Set of equivalent lorries for Fatigue Load Model 4 18 Table NA.6 – Forces due to collision with vehicle restraint systems for determining global effects 20 Table NA.7 – Recommended crowd densities for design 25 Table NA.8 – Parameters to be used in the calculation of pedestrian response 27 Table NA.9 – Recommended values for the site usage factor k1 30 Table NA.10 – Recommended values for the route redundancy factor k2 30 |
4 | Table NA.11 – Recommended values for the structure height factor k3 30 Table NA.12 – Nominal longitudinal loads 34 |
5 | Introduction NA.1 Scope a) the UK decisions for the Nationally Determined Parameters described in the following subclauses of BS EN 1991-2:2003: |
6 | b) the UK decisions on the status of BS EN 1991-2:2003 informative annexes; c) references to non-contradictory complementary information. NA.2 Nationally determined parameters NA.2.1 Complementary conditions [BS EN 1991-2:2003, 1.1 (3)] NA.2.2 Infrequent values of loads [BS EN 1991-2:2003, 2.2 (2) Note 2] NA.2.3 Appropriate protection against collision [BS EN 1991-2:2003, 2.3 (1)] NA.2.4 Impact forces due to boats, ships or aeroplanes [BS EN 1991-2:2003, 2.3 (4)] |
7 | NA.2.5 Bridges carrying both road and rail traffic [BS EN 1991-2:2003, 3 (5)] NA.2.6 Models for loaded lengths greater than 200 m [BS EN 1991-2:2003, 4.1 (1) Note 2] NA.2.7 Weight restricted bridges [BS EN 1991-2:2003, 4.1 (2)] NA.2.8 Complementary load models [BS EN 1991-2:2003, 4.2.1 (1)] NA.2.9 Models for special vehicles [BS EN 1991-2:2003, 4.2.1 (2)] NA.2.10 Conventional height of kerbs [BS EN 1991-2:2003, 4.2.3 (1)] NA.2.11 Use of Load Model 2 [BS EN 1991-2:2003, 4.3.1 (2) (b)] NA.2.12 Adjustment factors ! for Load Model 1 [BS EN 1991-2:2003, 4.3.2 (3) Notes 1 and 2] |
8 | Table NA.1 Adjustment factors !Q and !q for Load Model 1 NA.2.13 Use of simplified alternative Load Models [BS EN 1991-2:2003, 4.3.2 (6)] NA.2.14 Adjustment factor ” for Load Model 2 [BS EN 1991-2:2003, 4.3.3 (2)] NA.2.15 Wheel contact surface for Load Model 2 [BS EN 1991-2:2003, 4.3.3 (4)] NA.2.16 Load Model 3 (Special Vehicles) [BS EN 1991-2:2003, 4.3.4 (1)] NA.2.16.1 Basic models for STGO vehicles NA.2.16.1.1 SV80 |
9 | NA.2.16.1.2 SV100 NA.2.16.1.3 SV196 Figure NA.1 Basic longitudinal configuration of SV model vehicles |
10 | Figure NA.1 Basic longitudinal configuration of SV model vehicles (continued) |
11 | NA.2.16.2 Basic models for Special Order Vehicles Figure NA.2 Basic longitudinal configuration of SOV model vehicles |
12 | Figure NA.2 Basic longitudinal configuration of SOV model vehicles (continued) |
13 | Figure NA.3 Lateral wheel arrangement for trailer axles of all SOV models NA.2.16.3 Dynamic amplification factors Table NA.2 Dynamic Amplification Factors for the SV and SOV vehicles NA.2.16.4 Application of special vehicle models on the carriageway |
15 | Figure NA.4 Typical application of SV or SOV and Load Model 1 loading when the SV or SOV vehicle lies fully within a notional lane Figure NA.5 Typical application of SV or SOV and Load Model 1 loading when the SV or SOV vehicle straddles two adjacent lanes |
16 | NA.2.17 Upper limit of the braking force on road bridges [BS EN 1991-2:2003, 4.4.1 (2)] NA.2.18 Horizontal forces associated with Load Model 3 [BS EN 1991-2:2003, 4.4.1 (3)] NA.2.18.1 Longitudinal braking and acceleration forces NA.2.18.2 Centrifugal force |
17 | NA.2.19 Horizontal force transmitted by expansion joints or applied to structural members [BS EN 1991-2:2003, 4.4.1 (6)] NA.2.20 Lateral forces on road bridge decks [BS EN 1991-2:2003, 4.4.2 (4)] NA.2.21 Groups of traffic loads [BS EN 1991-2:2003, 4.5.1 Table 4.4a Notes a) and b)] |
18 | Table NA.3 Assessment of groups of traffic loads (characteristic values of the multi-component action) |
19 | NA.2.22 Conditions for use of Fatigue Load Models [BS EN 1991-2:2003, 4.6.1 (2) Note 2c] NA.2.23 Definition of traffic categories and traffic flows [BS EN 1991-2:2003, 4.6.1 (3) Note 1] |
20 | Table NA.4 Indicative numbers of heavy goods vehicles expected per year and per lane in the United Kingdom NA.2.24 Dynamic additional amplification factor due to expansion joints [BS EN 1991-2:2003, 4.6.1 (6)] NA.2.25 Fatigue Load Model 3 [BS EN 1991-2:2003, 4.6.4 (3)] NA.2.26 Fatigue Load Model 4 [BS EN 1991-2:2003, 4.6.1 (2) Note 2(e), 4.6.5 (1) Note 2] |
22 | Table NA.5 Set of equivalent lorries for Fatigue Load Model 4 |
23 | NA.2.27 Fatigue Load Model 5 (based on recorded traffic data) [BS EN 1991-2:2003, 4.6.6 (1)] NA.2.28 Collision forces on piers and other supporting members [BS EN 1991-2:2003, 4.7.2.1 (1)] NA.2.29 Collision forces on decks [BS EN 1991-2:2003, 4.7.2.2 (1) Note 1] NA.2.30 Effects of collision forces on vehicle restraint systems [BS EN 1991-2:2003, 4.7.3.3] NA.2.30.1 [BS EN 1991-2:2003, 4.7.3.3 (1) Note 1] |
24 | Table NA.6 Forces due to collision with vehicle restraint systems for determining global effects NA.2.30.2 [BS EN 1991-2:2003, 4.7.3.3 (1) Note 3] NA.2.30.3 [BS EN 1991-2:2003, 4.7.3.3 (2) Note] NA.2.31 Collision forces on structural members [BS EN 1991-2:2003, 4.7.3.4(1)] |
25 | NA.2.32 Actions on pedestrian parapets [BS EN 1991-2:2003, 4.8 (1) Note 2] NA.2.33 Supporting structures to pedestrian parapets, which are not adequately protected against vehicle collisions [BS EN 1991-2:2003, 4.8 (3)] NA.2.34 Model for vertical loads on backfill behind abutments and wing walls adjacent to bridges [BS EN 1991-2:2003, 4.9.1 (1) Note 1] NA.2.34.1 General NA.2.34.2 Loading from normal traffic |
26 | Figure NA.6 Vehicle model for abutments and wing walls |
27 | NA.2.34.3 Loading from special vehicles NA.2.35 Load models for inspection gangways [BS EN 1991-2:2003, 5.2.3 (2)] NA.2.36 Uniformly distributed load [BS EN 1991-2:2003, 5.3.2.1 (1)] NA.2.37 Concentrated load [BS EN 1991-2:2003, 5.3.2.2 (1)] |
28 | NA.2.38 Service vehicle [BS EN 1991-2:2003, 5.3.2.3 (1) Note 1] NA.2.39 Horizontal force on footbridges [BS EN 1991-2:2003, 5.4 (2)] NA.2.40 General actions for accidental design situations for footbridges [BS EN 1991-2:2003, 5.6.1 (1)] NA.2.41 Collision forces on piers of footbridges [BS EN 1991-2:2003, 5.6.2.1 (1)] NA.2.42 Collision forces on decks of footbridges [BS EN 1991-2:2003, 5.6.2.2 (1)] NA.2.43 Accidental presence of a heavy vehicle [BS EN 1991-2:2003, 5.6.3 (2)] NA.2.44 Dynamic models for pedestrian actions on footbridges [BS EN 1991-2:2003, 5.7 (3)] NA.2.44.1 General a) the determination of the maximum vertical deck acceleration and its comparison with the comfort criteria (as described in NA.2.44.3 to NA.2.44.6), and b) an analysis to determine the likelihood of large synchronized lateral responses (as described in NA.2.44.7). |
29 | NA.2.44.2 Dynamic actions to be considered (1) All bridges should be categorized into bridge classes by their usage to determine the appropriate actions due to pedestrians. Group sizes for each bridge class should be applied as given in Table NA.7. Table NA.7 Recommended crowd densities for design (2) Crowd loading densities to be used in design should be determined for the individual project and be appropriate for the intended bridge usage. Table NA.7 provides recommended values of crowd densities for each bridge class. (3) Depending on the expected bridge usage, it may be determined that jogging cases given in Table NA.7 can be neglected for individual projects. NA.2.44.3 Vertical response calculations (1) It should be demonstrated that the peak vertical deck accelerations determined for the actions described in NA.2.44.4 and NA.2.44.5 are less than the limits defined in NA.2.44.6. (2) In calculating the peak vertical deck accelerations account should be taken of the following. |
30 | NA.2.44.4 Dynamic actions representing the passage of single pedestrians and pedestrian groups (1) The design maximum vertical accelerations that result from single pedestrians or pedestrian groups should be calculated by a… |
31 | Figure NA.7 Effective span calculation Table NA.8 Parameters to be used in the calculation of pedestrian response Figure NA.8 Relationships between k(fv) and mode frequencies fv |
32 | Figure NA.9 Reduction factor, *, to allow for the unsynchronized combination of pedestrian actions within groups and crowds NA.2.44.5 Steady state modelling of pedestrians in crowded conditions (1) The design maximum vertical accelerations that result from pedestrians in crowded conditions may be calculated by assuming t… |
33 | (2) In order to obtain the most unfavourable effect this loading should be applied over all relevant areas of the footbridge dec… (3) Understanding of the dynamic response of structures in crowded conditions is still evolving and there is evidence to suggest… NA.2.44.6 Recommended serviceability limits for use in design (1) The maximum vertical acceleration calculated from the above actions should be less than the design acceleration limit given by: |
34 | Table NA.9 Recommended values for the site usage factor k1 Table NA.10 Recommended values for the route redundancy factor k2 Table NA.11 Recommended values for the structure height factor k3 |
35 | Figure NA.10 Response modifiers (2) k4 may be assigned a value of between 0.8 and 1.2 to reflect other conditions that may affect the users’ perception towards … (3) For some types of bridges (for example bridges in remote locations), less onerous design limits may be applied, where a suit… NA.2.44.7 The avoidance of unstable lateral responses due to crowd loading (1) Structures should be designed to avoid unintended unstable lateral responses. (2) If there are no significant lateral modes with frequencies below 1.5 Hz it may be assumed that unstable lateral responses will not occur. (3) For all other situations, it should be demonstrated that unstable lateral responses due to crowd loading will not occur, using the following method. |
37 | Figure NA.11 Lateral lock-in stability boundaries NA.2.45 Alternative load models for railway bridges [BS EN 1991-2:2003, 6.1 (2)] NA.2.45.1 Actions for non-public footpaths |
38 | NA.2.45.2 Actions due to traction and braking Table NA.12 Nominal longitudinal loads |
39 | NA.2.46 Other types of railways [BS EN 1991-2:2003, 6.1 (3)P] NA.2.47 Temporary bridges [BS EN 1991-2:2003, 6.1 (7)] NA.2.48 Values of a factor [BS EN 1991-2:2003, 6.3.2 (3)P] NA.2.49 Choice of lines for heavy rail traffic [BS EN 1991-2:2003, 6.3.3 (4)P] NA.2.50 Alternative requirements for a dynamic analysis [BS EN 1991-2:2003, 6.4.4 (1)] |
40 | Figure NA.12 Flow chart for determining whether a dynamic analysis is necessary for “simple” structures |
42 | Figure NA.13 Flow chart for determining whether a dynamic analysis is required for “simple” and “complex” structures |
44 | Figure NA.14 Limits of bridge natural frequency n0 in Hz as a function of L in m |
45 | NA.2.51 Choice of dynamic factor [BS EN 1991-2:2003, 6.4.5.2 (3)P] NA.2.52 Alternative values of determinant length [BS EN 1991-2:2003, 6.4.5.3 (1) Table 6.2] NA.2.53 Determinant length of transverse cantilevers [BS EN 1991-2:2003, 6.4.5.3, Note a, Table 6.2] NA.2.54 Additional requirements for the application of HSLM [BS EN 1991-2:2003, 6.4.6.1.1 (6), Table 6.4] NA.2.55 Loading and methodology for dynamic analysis [BS EN 1991-2:2003, 6.4.6.1.1 (7)] NA.2.56 Additional load cases depending upon number of tracks [BS EN 1991-2:2003, 6.4.6.1.2 (3), Table 6.5, Note a)] NA.2.57 Values of damping [BS EN 1991-2:2003, 6.4.6.3.1 (3) Table 6.6] |
46 | NA.2.58 Alternative density values of materials [BS EN 1991-2:2003, 6.4.6.3.2 (3)] NA.2.59 Enhanced Young’s modulus [BS EN 1991-2:2003, 6.4.6.3.3 (3) Note 1] NA.2.60 Other material properties [BS EN 1991-2:2003, 6.4.6.3.3 (3) Note 2] NA.2.61 Reduction of peak response at resonance taking account of additional damping due to vehicle/bridge interaction [BS EN 1991-2:2003, 6.4.6.4 (4)] NA.2.62 Allowance for track defects and vehicle imperfections [BS EN 1991-2:2003, 6.4.6.4 (5)] NA.2.63 Increased height of centre of gravity for centrifugal forces [BS EN 1991-2:2003, 6.5.1 (2)] NA.2.64 Actions due to braking for loaded lengths greater than 300 m [BS EN 1991-2:2003, 6.5.3 (5)] NA.2.65 Alternative requirements for the application of traction and braking forces [BS EN 1991-2:2003, 6.5.3 (9)] |
47 | NA.2.66 Combined response of structure and track, requirements for non-ballasted track [BS EN 1991-2:2003, 6.5.4.1 (5)] NA.2.67 Alternative requirements for temperature range [BS EN 1991-2:2003, 6.5.4.3 (2) Notes 1 and 2] NA.2.68 Longitudinal shear resistance between track and bridge deck [BS EN 1991-2:2003, 6.5.4.4 (2) Note 1] NA.2.69 Alternative design criteria [BS EN 1991-2:2003, 6.5.4.5] NA.2.70 Minimum value of track radius [BS EN 1991-2:2003, 6.5.4.5.1 (2)] NA.2.71 Alternative calculation methods [BS EN 1991-2:2003, 6.5.4.6] NA.2.72 Alternative criteria for simplified calculation methods [BS EN 1991-2:2003, 6.5.4.6.1 (1)] NA.2.73 Longitudinal plastic shear resistance between track and bridge deck [BS EN 1991-2:2003, 6.5.4.6.1 (4)] NA.2.74 Aerodynamic actions, alternative values [BS EN 1991-2:2003, 6.6.1 (3)] |
48 | NA.2.75 Derailment of rail traffic, additional requirements [BS EN 1991-2:2003, 6.7.1 (2)P] NA.2.76 Derailment of rail traffic, measures for structural elements situated above the level of the rails and requirements to retain a derailed train on the structure [BS EN 1991-2:2003, 6.7.1 (8)P Note 1] NA.2.77 Other actions [BS EN 1991-2:2003, 6.7.3 (1)P Note] NA.2.78 Number of tracks loaded when checking drainage and structural clearances [BS EN 1991-2:2003, 6.8.1 (11)P Table 6.10] NA.2.79 Assessment of groups of loads [BS EN 1991-2:2003, 6.8.2 (2)] NA.2.80 Frequent values of multi-component actions [BS EN 1991-2:2003, 6.8.3.1 (1)] |
49 | NA.2.81 Quasi-permanent values of multi-component actions [BS EN 1991-2:2003, 6.8.3.2 (1)] NA.2.82 Fatigue load models, structural life [BS EN 1991-2:2003, 6.9 (6)] NA.2.83 Fatigue load models, specific traffic [BS EN 1991-2:2003, 6.9 (7)] NA.2.84 Dynamic factor [BS EN 1991-2:2003, Annex C (3)P] NA.2.85 Method of dynamic analysis [BS EN 1991-2:2003, Annex C (3)P] NA.2.86 Partial safety factor for fatigue loading [BS EN 1991-2:2003, Annex D2 (2)] NA.3 Decision on the status of informative annexes NA.3.1 Load Model 3: Models of special vehicles [BS EN 1991-2:2003, Annex A] NA.3.2 Fatigue life assessment for road bridges: Assessment method based on recorded traffic [BS EN 1991-2:2003, Annex B] |
50 | NA.3.3 Limits of validity of Load Model HSLM [BS EN 1991-2:2003, Annex E] NA.3.4 Criteria to be satisfied if a dynamic analysis is not required [BS EN 1991-2:2003, Annex F] NA.3.5 Combined responses [BS EN 1991-2:2003, Annex G] NA.3.6 Load Models for rail traffic loads [BS EN 1991-2:2003, Annex H] NA.4 References to non-contradictory complementary information |
51 | Bibliography |