1、 INSTRUCTIONS AND INFORMATION 2010 INTERIM REVISIONS AASHTO LRFD MOVABLE BRIDGE DESIGN SPECIFICATIONS iiiINSTRUCTIONS AND INFORMATION General AASHTO has issued proposed interim revisions to AASHTO LRFD Movable Bridge Design Specifications, Second Edition (2007). This packet contains the revised page
2、s. They are not designed to replace the corresponding pages in the book but rather to be kept with the book for fast reference. Affected Articles Underlined text indicates revisions that were approved in 2010 by the AASHTO Highways Subcommittee on Bridges and Structures. Strikethrough text indicates
3、 any deletions that were likewise approved by the Subcommittee. A list of affected articles is included below. All interim pages are printed on blue paper to make the changes stand out when inserted in the second edition binder. They also have a page header displaying the section number affected and
4、 the interim publication year. Please note that these pages may also contain nontechnical (e.g. editorial) changes made by AASHTO publications staff; any changes of this type will not be marked in any way so as not to distract the reader from the technical changes. Although not applicable to this es
5、pecially short interim, please note that in response to user concerns, page breaks are now being added within sections between noncontiguous articles. This change makes it an option to insert the changes closer to the affected articles. Table i2010 Changed Article SECTION 8: ELECTRICAL DESIGN 8.6.1.
6、5 2010 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.2010 INTERIM TO THE AASHTO LRFD SECTION 8 MOVABLE HIGHWAY BRIDGE DESIGN SPECIFICATIONS 1SECTION 8: ELECTRICAL DESIGN 8.6.1.5Variable Frequency Speed Cont
7、rol Revise the following Article as follows: In general, Volts-hertz type variable frequency drives should shall not be used for movable bridge drives. C8.6.1.5 Replace the existing commentary with the following: Volts-hertz type variable frequency speed control has seen limited success for speed co
8、ntrol of movable bridges. While these drives are compatible with squirrel cage induction motors, inverter duty motors should be considered for their ability to withstand the higher harmonic voltages that may be produced. Volts-hertz type variable frequency drives have historically lacked the ability
9、 for precise control of torque at low speed. Control of torque under overhauling loads and stall conditions, such as seating, has sometimes been unsuccessful. The exclusion of variable frequency drives in this Article is for volts-hertz type only. Flux vector variable frequency drives are acceptable
10、 as outlined in Article 8.6.1.6. 2010 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.INSTRUCTIONS AND INFORMATION 2011 INTERIM REVISIONS AASHTO LRFD MOVABLE BRIDGE DESIGN SPECIFICATIONS iii INSTRUCTIONS AND
11、INFORMATION General AASHTO has issued proposed interim revisions to AASHTO LRFD Movable Bridge Design Specifications, Second Edition (2007). This packet contains the revised pages. They are not designed to replace the corresponding pages in the book but rather to be kept with the book for fast refer
12、ence. Affected Articles Underlined text indicates revisions that were approved in 2011 by the AASHTO Highways Subcommittee on Bridges and Structures. Strikethrough text indicates any deletions that were likewise approved by the Subcommittee. A list of affected articles is included below. All interim
13、 pages are printed on blue paper to make the changes stand out when inserted in the second edition binder. They also have a page header displaying the section number affected and the interim publication year. Please note that these pages may also contain nontechnical (e.g. editorial) changes made by
14、 AASHTO publications staff; any changes of this type will not be marked in any way so as not to distract the reader from the technical changes. Although not applicable to this especially short interim, please note that in response to user concerns, page breaks are now being added within sections bet
15、ween noncontiguous articles. This change makes it an option to insert the changes closer to the affected articles. Table i2011 Changed Article SECTION 1: GENERAL PROVISIONS C.1.3.3 2011 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a vi
16、olation of applicable law.SECTION 1 2011 INTERIM REVISIONS AASHTO LRFD MOVABLE BRIDGE DESIGN SPECIFICATIONS 1 SECTION 1: GENERAL PROVISIONS Add the following commentary to Article 1.3.3: C1.3.3 The operating system is applicable to mechanical machinery design. 2011 by the American Association of Sta
17、te Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.2012 INTERIM REVISIONS AASHTO LRFD INSTRUCTIONS AND INFORMATION MOVABLE BRIDGE DESIGN SPECIFICATIONS iiiINSTRUCTIONS AND INFORMATION General AASHTO has issued interim revisions to AASHTO LRFD Mo
18、vable Bridge Design Specifications, Second Edition (2007). This packet contains the revised pages. They are not designed to replace the corresponding pages in the book but rather to be kept with the book for quick reference. Affected Articles Underlined text indicates revisions that were approved in
19、 2012 by the AASHTO Highways Subcommittee on Bridges and Structures. Strikethrough text indicates any deletions that were likewise approved by the Subcommittee. A list of affected articles is included below. All interim pages are printed on blue paper to make the changes stand out when inserted in t
20、he second edition binder. They also have a page header displaying the section number affected and the interim publication year. Please note that these pages may also contain nontechnical (e.g. editorial) changes made by AASHTO publications staff; any changes of this type will not be marked in any wa
21、y so as not to distract the reader from the technical changes. Please note that in response to user concerns, page breaks are now being added within sections between noncontigu-ous articles. This change makes it an option to insert the changes closer to the affected articles. Table i2012 Changed Art
22、icles SECTION 6: MECHANICAL DESIGN 6.6.3.2 6.8.1.5.1 2012 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.2012 INTERIM REVISIONS AASHTO LRFD SECTION 6 MOVABLE BRIDGE DESIGN SPECIFICATIONS 1SECTION 6: MECHANIC
23、AL DESIGN 6.6.3.2Endurance Limit Equation 6.6.3.2-3 should be modified as follows: For D 0.3 in., CD= (D / 7.6 ) (3.342D)0.113 2012 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.2012 INTERIM REVISIONS AASHT
24、O LRFD SECTION 6 MOVABLE BRIDGE DESIGN SPECIFICATIONS 36.8.1.5.1Locking Devices Add the following commentary to Article 6.8.1.5.1: C6.8.1.5.1 The following interim guidance may be applied to the structural design of lock bars that are of uniform cross section and free of stress raisers: Design for S
25、trength I or II, or both; Service II; and Fatigue I or II limit states per the requirements of the AASHTO LRFD Bridge Design Specifications; Utilize twice the normal vehicular dynamic load allowance (IM) as per the requirements of the AASHTO LRFD Bridge Design Specifications Article 3.6.2 for nondec
26、k joint components and consider the full stress range (stress reversal) caused by passage of the design truck from one side of the center lock to the other for fatigue design; The receiver components or guideways for the lock bars shall be designed based on these Specifications. Additional research
27、is anticipated in the future for the span lock bar and receiver components, investigating revisions to the factors of safety and load factors. 2012 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.2014 INTERIM
28、 REVISIONS AASHTO LRFD INSTRUCTIONS AND INFORMATION MOVABLE BRIDGE DESIGN SPECIFICATIONS iiiINSTRUCTIONS AND INFORMATION General AASHTO has issued interim revisions to AASHTO LRFD Movable Bridge Design Specifications, Second Edition (2007). This packet contains the revised pages. They are not design
29、ed to replace the corresponding pages in the book but rather to be kept with the book for quick reference. Affected Articles Underlined text indicates revisions that were approved in 2013 by the AASHTO Highways Subcommittee on Bridges and Structures. Strikethrough text indicates any deletions that w
30、ere likewise approved by the Subcommittee. A list of affected articles is included below. Please note: starting with this ballot year, the subcommittee has asked that their interims be dated the calendar year after the ballot year for consistency, even though some smaller interims, like this one, ma
31、y be released in the same calendar year. All interim pages are printed on pink paper to make the changes stand out when inserted in the second edition binder. They also have a page header displaying the section number affected and the interim publication year. Please note that these pages may also c
32、ontain nontechnical (e.g. editorial) changes made by AASHTO publications staff; any changes of this type will not be marked in any way so as not to distract the reader from the technical changes. Please note that in response to user concerns, page breaks are now being added within sections between n
33、oncontiguous articles. This change makes it an option to insert the changes closer to the affected articles. Table i2012 Changed Articles SECTION 6: MECHANICAL DESIGN 6.6.3.2 6.7.4.2 6.7.5.1 6.7.5.2.2 6.7.5.2.3 6.7.5.2.4 6.7.7.2.4 6.7.10.1 6.8.3.3.4 6.8.3.3.6 6.8.3.4.2 2013 by the American Associati
34、on of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.2014 INTERIM REVISIONS AASHTO LRFD SECTION 6 MOVABLE BRIDGE DESIGN SPECIFICATIONS 1SECTION 6: MECHANICAL DESIGN 6.6.3.2Endurance Limit Equation 6.6.3.2-4 should be modified as follows:
35、 ( )bSutCa=1000butSCa= 2013 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.2014 INTERIM REVISIONS AASHTO LRFD SECTION 6 MOVABLE BRIDGE DESIGN SPECIFICATIONS 36.7.4.2Shaft Length and Deformation Modify the s
36、econd bullet as follows: Where less twist is desirable, as in shafts driving end-lifting devices(0.006) (0.00667) 2013 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.2014 INTERIM REVISIONS AASHTO LRFD SECTI
37、ON 6 MOVABLE BRIDGE DESIGN SPECIFICATIONS 56.7.5Design of Open Spur Gearing 6.7.5.1General Revise paragraphs 5 and 6 as follows: For full depth spur gear teeth, the addendum shall be the inverse of the diametral pitch (equal to the tooth module), the dedendum shall be 1.250 divided by the diametral
38、pitch (1.157 times the module), and the circular pitch shall be divided by the diametral pitch ( times the tooth module). The face width of a spur gear should be not less than 8/Pd, nor more than 14Pd14/Pd(not less than 8, nor more than 14, times the tooth module). Revise the second bullet list as f
39、ollows: for pinions other than motor pinions, transmitting power for moving the span3.14 in. in.1 for motor pinions.4.19 in. in.1 for main rack teeth2.09 in. in.1 2013 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applic
40、able law.2014 INTERIM REVISIONS AASHTO LRFD SECTION 6 MOVABLE BRIDGE DESIGN SPECIFICATIONS 76.7.5.2.2Design for the Fatigue Limit State Modify the second to last bullet as follows: 1.00 for 99 percent reliability 1.25 for 99.9 percent reliability 6.7.5.2.3Surface Durability and WearDesign Equations
41、In paragraph 2, make the following change: The factored surface durability resistance, Ftaz(N) Wtac(lb), of the spur gear teeth based on pitting resistance 2013 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable la
42、w.2014 INTERIM REVISIONS AASHTO LRFD SECTION 6 MOVABLE BRIDGE DESIGN SPECIFICATIONS 96.7.5.2.4Yield Failure at Intermittent Overload Modify where list item as follows: Kf = stress correction factor = 1 (dim) 2013 by the American Association of State Highway and Transportation Officials. All rights r
43、eserved. Duplication is a violation of applicable law.2014 INTERIM REVISIONS AASHTO LRFD SECTION 6 MOVABLE BRIDGE DESIGN SPECIFICATIONS 116.7.7.2.4Sizing of Large Rolling Element Bearings Modify the second where list as follows: Xo= a static axial radial load factor (dim) Yo= a static radial axial l
44、oad factor (dim) 2013 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.2014 INTERIM REVISIONS AASHTO LRFD SECTION 6 MOVABLE BRIDGE DESIGN SPECIFICATIONS 136.7.10Keys and Keyways 6.7.10.1General In Table C6.7.
45、10.1-1, modify rows 12 and 13 as follows: 4 1/25 1/21 1/2 1 1/211/4 11/45 1/26 1/232 1 1/2 11/2 11/2 2013 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.2014 INTERIM REVISIONS AASHTO LRFD SECTION 6 MOVABLE
46、BRIDGE DESIGN SPECIFICATIONS 156.8.3.3.4Wire Rope Stresses In the commentary, move the paragraph that follows across from “Po” in the where list: When determining Pofor counterweight ropes, only inertial loads are effective. 2013 by the American Association of State Highway and Transportation Offici
47、als. All rights reserved. Duplication is a violation of applicable law.2014 INTERIM REVISIONS AASHTO LRFD SECTION 6 MOVABLE BRIDGE DESIGN SPECIFICATIONS 176.8.3.3.6Wire Rope Tensile Strengths In the commentary, modify the last paragraph as follows: ER(psi) Percent of Ultimate Load 10.8 106(74 500) 0
48、20 12 106(83 000) 2165 2013 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.2014 INTERIM REVISIONS AASHTO LRFD SECTION 6 MOVABLE BRIDGE DESIGN SPECIFICATIONS 196.8.3.4.2Counterweight Sheaves In the last para
49、graph, modify the last sentence as follows: The distance center-to-center of grooves shall be at least 6.5 mm 0.25 in. more than the diameter of the rope. 2013 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.2015 INTERIM REVISIONS AASHTO LRFD INSTRUCTIONS AND INFORMATION MOVABLE BRIDGE DESIGN SPECIFICATI
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