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1、AS 5100.72004 AP-G15.7/04 Australian Standard Bridge design Part 7: Rating of existing bridges AS 5100.7 Accessed by TAFE QUEENSLAND INSTITUTES on 19 Dec 2007 This Australian Standard was prepared by Committee BD-090, Bridge Design. It was approved on behalf of the Council of Standards Australia on
2、22 August 2003 and published on 23 April 2004. The following are represented on Committee BD-090: Association of Consulting Engineers Australia Australasian Railway Association Austroads Bureau of Steel Manufacturers of Australia Cement and Concrete Association of Australia Institution of Engineers
3、Australia Queensland University of Technology Steel Reinforcement Institute of Australia University of Western Sydney Keeping Standards up-to-date Standards are living documents which reflect progress in science, technology and systems. To maintain their currency, all Standards are periodically revi
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7、dards, and especially encourage readers to notify us immediately of any apparent inaccuracies or ambiguities. Contact us via email at mailstandards.org.au, or write to the Chief Executive, Standards Australia International Ltd, GPO Box 5420, Sydney, NSW 2001. This Standard was issued in draft form f
8、or comment as DR 00380. Accessed by TAFE QUEENSLAND INSTITUTES on 19 Dec 2007 AS 5100.72004 AP-G15.7/04 Australian Standard Bridge design Part 7: Rating of existing bridges Originated as HB 77.71996. Revised and redesignated as AS 5100.72004. COPYRIGHT Standards Australia International All rights ar
9、e reserved. No part of this work may be reproduced or copied in any form or by any means, electronic or mechanical, including photocopying, without the written permission of the publisher. Published by Standards Australia International Ltd GPO Box 5420, Sydney, NSW 2001, Australia ISBN 0 7337 5500 3
10、 Accessed by TAFE QUEENSLAND INSTITUTES on 19 Dec 2007 AS 5100.72004 2 PREFACE This Standard was prepared by the Standards Australia Committee BD-090, Bridge Design, to supersede HB 77.71996, Australian Bridge Design Code, Section 7: Rating. The AS 5100 series represents a revision of the 1996 HB 77
11、 series, Australian Bridge Design Code, which contained a separate Railway Supplement to Sections 1 to 5, together with new Section 6, Steel and composite construction, and Section 7, Rating. AS 5100 takes the requirements of the Railway Supplement and incorporates them into Parts 1 to 5 of the pres
12、ent series, to form integrated documents covering requirements for both road and rail bridges. In addition, technical material has been updated. This Standard is also designated as AUSTROADS publication AP-G15.7/04. The objectives of AS 5100 are to provide nationally acceptable requirements for (a)
13、the design of road, rail, pedestrian and bicycle-path bridges; (b) the specific application of concrete, steel and composite steel/concrete construction method, which embody principles that may be applied to other materials in association with relevant Standards; and (c) the assessment of the load c
14、apacity of existing bridges. These requirements are based on the principles of structural mechanics and knowledge of material properties, for both the conceptual and detailed design, to achieve acceptable probabilities that the bridge or associated structure being designed will not become unfit for
15、use during its design life. Whereas earlier editions of the Australian Bridge Design Code were essentially administered by the infrastructure owners and applied to their own inventory, an increasing number of bridges are being built under the design-construct-operate principle and being handed over
16、to the relevant statutory authority after several years of operation. This Standard includes clauses intended to facilitate the specification to the designer of the functional requirements of the owner, to ensure the long-term performance and serviceability of the bridge and associated structure. Si
17、gnificant changes have been made to HB 77.71996 following recent research and experience in Australia. Load testing to supplement theoretical assessment of the load capacity of the structure has been included. In line with Standards Australia policy, the words shall and may are used consistently thr
18、oughout this Standard to indicate respectively, a mandatory provision and an acceptable or permissible alternative. Statements expressed in mandatory terms in Notes to Tables are deemed to be requirements of this Standard. The term informative has been used in this Standard to define the application
19、 of the appendix to which it applies. An informative appendix is only for information and guidance. Accessed by TAFE QUEENSLAND INSTITUTES on 19 Dec 2007 3 AS 5100.72004 CONTENTS Page 1 SCOPE AND GENERAL .4 2 REFERENCED DOCUMENTS5 3 NOTATION5 4 RATING PHILOSOPHY6 5 ASSESSMENT OF LOAD CAPACITY.8 6 LO
20、AD TESTING 10 7 ASSESSMENT OF THE ACTUAL LOADS 14 8 FATIGUE. 16 APPENDIX A ROAD AND RAIL TRAFFIC DESIGN LOADS FROM PREVIOUS AUSTRALIAN BRIDGE DESIGN CODE, AUSTROADS CODES, ANZRC AND AREA 18 Accessed by TAFE QUEENSLAND INSTITUTES on 19 Dec 2007 AS 5100.72004 4 Standards Australia .au STANDARDS AUSTRA
21、LIA Australian Standard Bridge design Part 7: Rating of existing bridges 1 SCOPE AND GENERAL 1.1 Scope This Standard specifies procedures for rating the safe load capacity of a bridge for its defined remaining service life. The initial rating of a bridge will be its nominal design load, but it may s
22、ubsequently be rated as a result of (a) a requirement for it to carry increased live or other loads; (b) suffering physical damage from actions including vehicle overloading, accidental impact, fire, flood or scour; or (c) deterioration of its components, e.g., by chemical or physical weathering. NO
23、TE: For road and rail traffic design loads from previous Australian Bridge Design Code, Austroads Codes, ANZRC and AREA, see Appendix A. 1.2 General In assessing the load capacity of a bridge, all relevant components of the bridge, including its foundation, shall be considered to ensure that all cri
24、tical components are assessed and that their interactive effect on the overall structure has been taken into account. Whereas this Standard allows for normal uncertainties in the general design of bridges, in the case of a specific existing bridge, by carrying out comprehensive inspections and inves
25、tigations, the factors causing uncertainty can be more precisely defined. As a consequence, the levels of repeatable live loads that are permitted on a bridge may be able to be increased without compromising the safety or service life of the bridge. Conversely, if the condition of the bridge element
26、s has deteriorated or the uncertainty of performance has increased, the load rating may need to be reduced. The methodology used to assess the load capacity of a bridge shall be based on ensuring the same level of risk in the specific case as required for the general case. The capacity of a bridge s
27、hall be assessed using the design procedures specified in other parts of the AS 5100 series and as specified in this Standard for more detailed methods of assessment. A tiered approach involving the use of increasing levels of sophistication or broadened scope may be justified, depending upon the co
28、sts involved and the importance of trying to prove increased load capacity for a specific bridge. The tiered approaches include (i) theoretical analysis based on the design parameters in this Standard taking the condition of the bridge into consideration; (ii) analysis using the results of field inv
29、estigation of material properties, bridge component dimensions, dead and live loads, foundation capacity and the like; (iii) field or laboratory test loading; and (iv) component condition assessment. Accessed by TAFE QUEENSLAND INSTITUTES on 19 Dec 2007 5 AS 5100.72004 .au Standards Australia A brid
30、ge rating shall confirm that the bridge is able to carry its rated capacity, including the impact effects of an appropriate dynamic load allowance. This dynamic load allowance shall be in accordance with this Standard or an appropriate modified value based on measurement, detailed assessment, or con
31、trolled by the imposition of a speed restriction or other methods of control. Where specific measurements so indicate, an increased dynamic load allowance shall be considered. The dynamic load allowance is sensitive to the road profiles on the bridge and its approaches as well as the characteristics
32、, speed and mass of the vehicle(s) inducing the dynamic effects. Rating shall be based on confirmed details of the structure, including design and as constructed records. All assumptions relevant to the rating shall be recorded. NOTES: 1 Unless road approaches to bridges are carefully maintained, ro
33、ad profiles may vary with time, potentially leading to increased dynamic loading on bridges. 2 When making an assessment of a metal structure or component, care should be taken to identify whether the material is cast iron, wrought iron or steel. 2 REFERENCED DOCUMENTS The following documents are re
34、ferred to in this Standard: AS 5100 Bridge design 5100.2 Part 2: Design loads 5100.3 Part 3: Foundations and soil-supporting structures 5100.5 Part 5: Concrete 5100.6 Part 6: Steel and composite construction HB 77.2 Australian Bridge Design CodeDesign loads Austroads Bridge Design Code Highway Bridg
35、e Design Specification NAASRA 3 NOTATION The symbols used in this Standard are listed in Table 3. Where non-dimensional ratios are involved, both the numerator and denominator are expressed in identical units. The units for length and stress in all expressions or equations are to be taken as millime
36、tres (mm) and megapascals (MPa) respectively, unless specifically noted otherwise. Accessed by TAFE QUEENSLAND INSTITUTES on 19 Dec 2007 AS 5100.72004 6 Standards Australia .au TABLE 3 NOTATION Symbols Description Clause reference ALF accompanying lane factor 4.2 kadjustment factor taking into accou
37、nt any distress level reached during load testing 6.4.3 LRrated load 4.2, 6.4.3 LRVnominated rating vehicle 4.1 MTF multiple track factor 4.2 PLmax. maximum applied test load 6.4.3 RFrating factor 4.2 Rucalculated ultimate capacity 4.2 rmmodification ratio Table 7.3 * g Sload effects due to dead loa
38、d 4.2 * gs S load effects due to superimposed dead load 4.2 * L S load effects due to the live load used for the assessment 4.2 * p S load effects due to parasitic effects of prestress 4.2 * s S load effects due to differential settlement 4.2 * t S load effects due to differential temperature 4.2 dy
39、namic load allowance 4.2 HL dynamic load allowance for a heavy load platform or other specific loads 7.1 g load factor for dead load Table 7.3 gsload factor for superimposed dead load Table 7.3 L live load factor 6.4.3 LRAload factor for specific loads Table 7.3 capacity reduction factor 4.2 4 RATIN
40、G PHILOSOPHY 4.1 General The concept of rating is based on the limit states design principle that the assessed minimum strength capacity of the bridge shall be greater than the assessed maximum load applied. Both serviceability and ultimate limit state capacities shall be considered. Rating relates
41、primarily to the live load condition, including dynamic effects. The procedure shall be to rate the available live load capacity of the bridge compared with the effects of a nominated rating vehicle (LRV), that is (a) the SM1600 loading for general capacity rating; (b) a specific live load configura
42、tion for general access vehicles, for example, a legal limit loading; or (c) a specific live load configuration for restricted access vehicles, for example, an indivisible heavy loading operating under nominated conditions. 4.2 Rating equation The rating of a bridge is carried out by comparing the f
43、actored live load effects of the nominated rating vehicle with the factored strength of the bridge after subtracting the Accessed by TAFE QUEENSLAND INSTITUTES on 19 Dec 2007 7 AS 5100.72004 .au Standards Australia strength capacities required to meet the factored dead and superimposed dead load eff
44、ects and parasitic, differential temperature and differential settlement effects. The ability of a bridge to carry repeated general access live loads is assessed as a proportion of a nominated general access rating vehicle. Similarly, the ability of a bridge to carry a specific vehicle for a single
45、pass or a small number of passes is assessed as a proportion of a nominated restricted access vehicle, operating under nominated conditions, e.g., speed restriction, location on bridge deck. The rating procedure is carried out for all strength checks, e.g., moment, shear and the like, at all potenti
46、ally critical sections, with the lowest rating factor determined being the rating factor for the bridge. For the purpose of rating, the general strength equation for bridges is expressed as follows: ()()+1 * LL * t * s * p * gsgs * ggu WSRFSSSSSR. . . 4.2(1) The general equation to determine the rat
47、ing factor (RF) for bridges is therefore () () * LL * t * s * p * gsgs * ggu 1SW SSSSSR RF + + . . . 4.2(2) i.e., vehicleratingnominatedofeffectsloadLive effectsloadliveforcapacitybridgeAvailable =RF . . . 4.2(3) Therefore the rated load (LR) can be expressed as follows: () RVR LRFL=. . . 4.2(4) whe
48、re = capacity reduction factor Ru = calculated ultimate capacity g= load factor for dead load * g S= load effects due to dead load gs= load factor for the superimposed dead load * gs S= load effects due to superimposed dead load * p S= load effects due to parasitic effects or prestress * s S= load e
49、ffects due to differential settlement * t S= load effects due to differential temperature L= load factor for live load RF= rating factor * L S= load effects due to the live load used for the assessment W= a factor representing (a) MTF for railway traffic bridges, that is, the multiple track factor determined in accordance with AS 5100.2; and (b) ALF for road traffic bridges, that is, the accompanying lane factor determined i