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Updating the AASHTO LRFD Movable Highway Bridge Design Specifications (2021)

Chapter: Appendix A Literature Review Details

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Suggested Citation:"Appendix A Literature Review Details." National Academies of Sciences, Engineering, and Medicine. 2021. Updating the AASHTO LRFD Movable Highway Bridge Design Specifications. Washington, DC: The National Academies Press. doi: 10.17226/26395.
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Suggested Citation:"Appendix A Literature Review Details." National Academies of Sciences, Engineering, and Medicine. 2021. Updating the AASHTO LRFD Movable Highway Bridge Design Specifications. Washington, DC: The National Academies Press. doi: 10.17226/26395.
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Suggested Citation:"Appendix A Literature Review Details." National Academies of Sciences, Engineering, and Medicine. 2021. Updating the AASHTO LRFD Movable Highway Bridge Design Specifications. Washington, DC: The National Academies Press. doi: 10.17226/26395.
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Suggested Citation:"Appendix A Literature Review Details." National Academies of Sciences, Engineering, and Medicine. 2021. Updating the AASHTO LRFD Movable Highway Bridge Design Specifications. Washington, DC: The National Academies Press. doi: 10.17226/26395.
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Suggested Citation:"Appendix A Literature Review Details." National Academies of Sciences, Engineering, and Medicine. 2021. Updating the AASHTO LRFD Movable Highway Bridge Design Specifications. Washington, DC: The National Academies Press. doi: 10.17226/26395.
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Suggested Citation:"Appendix A Literature Review Details." National Academies of Sciences, Engineering, and Medicine. 2021. Updating the AASHTO LRFD Movable Highway Bridge Design Specifications. Washington, DC: The National Academies Press. doi: 10.17226/26395.
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Suggested Citation:"Appendix A Literature Review Details." National Academies of Sciences, Engineering, and Medicine. 2021. Updating the AASHTO LRFD Movable Highway Bridge Design Specifications. Washington, DC: The National Academies Press. doi: 10.17226/26395.
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Suggested Citation:"Appendix A Literature Review Details." National Academies of Sciences, Engineering, and Medicine. 2021. Updating the AASHTO LRFD Movable Highway Bridge Design Specifications. Washington, DC: The National Academies Press. doi: 10.17226/26395.
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Suggested Citation:"Appendix A Literature Review Details." National Academies of Sciences, Engineering, and Medicine. 2021. Updating the AASHTO LRFD Movable Highway Bridge Design Specifications. Washington, DC: The National Academies Press. doi: 10.17226/26395.
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Suggested Citation:"Appendix A Literature Review Details." National Academies of Sciences, Engineering, and Medicine. 2021. Updating the AASHTO LRFD Movable Highway Bridge Design Specifications. Washington, DC: The National Academies Press. doi: 10.17226/26395.
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Suggested Citation:"Appendix A Literature Review Details." National Academies of Sciences, Engineering, and Medicine. 2021. Updating the AASHTO LRFD Movable Highway Bridge Design Specifications. Washington, DC: The National Academies Press. doi: 10.17226/26395.
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Suggested Citation:"Appendix A Literature Review Details." National Academies of Sciences, Engineering, and Medicine. 2021. Updating the AASHTO LRFD Movable Highway Bridge Design Specifications. Washington, DC: The National Academies Press. doi: 10.17226/26395.
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Suggested Citation:"Appendix A Literature Review Details." National Academies of Sciences, Engineering, and Medicine. 2021. Updating the AASHTO LRFD Movable Highway Bridge Design Specifications. Washington, DC: The National Academies Press. doi: 10.17226/26395.
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Suggested Citation:"Appendix A Literature Review Details." National Academies of Sciences, Engineering, and Medicine. 2021. Updating the AASHTO LRFD Movable Highway Bridge Design Specifications. Washington, DC: The National Academies Press. doi: 10.17226/26395.
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Suggested Citation:"Appendix A Literature Review Details." National Academies of Sciences, Engineering, and Medicine. 2021. Updating the AASHTO LRFD Movable Highway Bridge Design Specifications. Washington, DC: The National Academies Press. doi: 10.17226/26395.
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Suggested Citation:"Appendix A Literature Review Details." National Academies of Sciences, Engineering, and Medicine. 2021. Updating the AASHTO LRFD Movable Highway Bridge Design Specifications. Washington, DC: The National Academies Press. doi: 10.17226/26395.
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Suggested Citation:"Appendix A Literature Review Details." National Academies of Sciences, Engineering, and Medicine. 2021. Updating the AASHTO LRFD Movable Highway Bridge Design Specifications. Washington, DC: The National Academies Press. doi: 10.17226/26395.
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Suggested Citation:"Appendix A Literature Review Details." National Academies of Sciences, Engineering, and Medicine. 2021. Updating the AASHTO LRFD Movable Highway Bridge Design Specifications. Washington, DC: The National Academies Press. doi: 10.17226/26395.
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Suggested Citation:"Appendix A Literature Review Details." National Academies of Sciences, Engineering, and Medicine. 2021. Updating the AASHTO LRFD Movable Highway Bridge Design Specifications. Washington, DC: The National Academies Press. doi: 10.17226/26395.
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Suggested Citation:"Appendix A Literature Review Details." National Academies of Sciences, Engineering, and Medicine. 2021. Updating the AASHTO LRFD Movable Highway Bridge Design Specifications. Washington, DC: The National Academies Press. doi: 10.17226/26395.
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Suggested Citation:"Appendix A Literature Review Details." National Academies of Sciences, Engineering, and Medicine. 2021. Updating the AASHTO LRFD Movable Highway Bridge Design Specifications. Washington, DC: The National Academies Press. doi: 10.17226/26395.
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Suggested Citation:"Appendix A Literature Review Details." National Academies of Sciences, Engineering, and Medicine. 2021. Updating the AASHTO LRFD Movable Highway Bridge Design Specifications. Washington, DC: The National Academies Press. doi: 10.17226/26395.
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Suggested Citation:"Appendix A Literature Review Details." National Academies of Sciences, Engineering, and Medicine. 2021. Updating the AASHTO LRFD Movable Highway Bridge Design Specifications. Washington, DC: The National Academies Press. doi: 10.17226/26395.
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Suggested Citation:"Appendix A Literature Review Details." National Academies of Sciences, Engineering, and Medicine. 2021. Updating the AASHTO LRFD Movable Highway Bridge Design Specifications. Washington, DC: The National Academies Press. doi: 10.17226/26395.
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Suggested Citation:"Appendix A Literature Review Details." National Academies of Sciences, Engineering, and Medicine. 2021. Updating the AASHTO LRFD Movable Highway Bridge Design Specifications. Washington, DC: The National Academies Press. doi: 10.17226/26395.
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Suggested Citation:"Appendix A Literature Review Details." National Academies of Sciences, Engineering, and Medicine. 2021. Updating the AASHTO LRFD Movable Highway Bridge Design Specifications. Washington, DC: The National Academies Press. doi: 10.17226/26395.
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Suggested Citation:"Appendix A Literature Review Details." National Academies of Sciences, Engineering, and Medicine. 2021. Updating the AASHTO LRFD Movable Highway Bridge Design Specifications. Washington, DC: The National Academies Press. doi: 10.17226/26395.
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Suggested Citation:"Appendix A Literature Review Details." National Academies of Sciences, Engineering, and Medicine. 2021. Updating the AASHTO LRFD Movable Highway Bridge Design Specifications. Washington, DC: The National Academies Press. doi: 10.17226/26395.
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Suggested Citation:"Appendix A Literature Review Details." National Academies of Sciences, Engineering, and Medicine. 2021. Updating the AASHTO LRFD Movable Highway Bridge Design Specifications. Washington, DC: The National Academies Press. doi: 10.17226/26395.
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Suggested Citation:"Appendix A Literature Review Details." National Academies of Sciences, Engineering, and Medicine. 2021. Updating the AASHTO LRFD Movable Highway Bridge Design Specifications. Washington, DC: The National Academies Press. doi: 10.17226/26395.
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Suggested Citation:"Appendix A Literature Review Details." National Academies of Sciences, Engineering, and Medicine. 2021. Updating the AASHTO LRFD Movable Highway Bridge Design Specifications. Washington, DC: The National Academies Press. doi: 10.17226/26395.
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Suggested Citation:"Appendix A Literature Review Details." National Academies of Sciences, Engineering, and Medicine. 2021. Updating the AASHTO LRFD Movable Highway Bridge Design Specifications. Washington, DC: The National Academies Press. doi: 10.17226/26395.
×
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Suggested Citation:"Appendix A Literature Review Details." National Academies of Sciences, Engineering, and Medicine. 2021. Updating the AASHTO LRFD Movable Highway Bridge Design Specifications. Washington, DC: The National Academies Press. doi: 10.17226/26395.
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Suggested Citation:"Appendix A Literature Review Details." National Academies of Sciences, Engineering, and Medicine. 2021. Updating the AASHTO LRFD Movable Highway Bridge Design Specifications. Washington, DC: The National Academies Press. doi: 10.17226/26395.
×
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Suggested Citation:"Appendix A Literature Review Details." National Academies of Sciences, Engineering, and Medicine. 2021. Updating the AASHTO LRFD Movable Highway Bridge Design Specifications. Washington, DC: The National Academies Press. doi: 10.17226/26395.
×
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Suggested Citation:"Appendix A Literature Review Details." National Academies of Sciences, Engineering, and Medicine. 2021. Updating the AASHTO LRFD Movable Highway Bridge Design Specifications. Washington, DC: The National Academies Press. doi: 10.17226/26395.
×
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Suggested Citation:"Appendix A Literature Review Details." National Academies of Sciences, Engineering, and Medicine. 2021. Updating the AASHTO LRFD Movable Highway Bridge Design Specifications. Washington, DC: The National Academies Press. doi: 10.17226/26395.
×
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Suggested Citation:"Appendix A Literature Review Details." National Academies of Sciences, Engineering, and Medicine. 2021. Updating the AASHTO LRFD Movable Highway Bridge Design Specifications. Washington, DC: The National Academies Press. doi: 10.17226/26395.
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Suggested Citation:"Appendix A Literature Review Details." National Academies of Sciences, Engineering, and Medicine. 2021. Updating the AASHTO LRFD Movable Highway Bridge Design Specifications. Washington, DC: The National Academies Press. doi: 10.17226/26395.
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Suggested Citation:"Appendix A Literature Review Details." National Academies of Sciences, Engineering, and Medicine. 2021. Updating the AASHTO LRFD Movable Highway Bridge Design Specifications. Washington, DC: The National Academies Press. doi: 10.17226/26395.
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52 A P P E N D I X A Literature Review Details AASHTO LRFD MHBDS 1. Document Information Document Reviewed: AASHTO LRFD MHBDS Publisher: American Association of State Highway and Transportation Officials Published Date of Document: 2nd Edition, 2007 with interims of 2010 and 2015 Initial Date: 2007 Latest Version: NA (if different from document reviewed) 2. General Description of Document: This specification covers design of movable highway bridges including movable bridge specific structural, machinery, hydraulic and electrical. Design is codified to specified limit states per the AASHTO LRFD Bridge Design Specifications. 3. Applicability to NCHRP 12-112 3.1 Components or Systems Covered: This specification covers design of movable bridge specific structural, machinery, hydraulic and electrical components and systems. 3.2 Reliability-Based Methodology: The specification overall is based on Load and Resistant Factor Design and the theory of reliability. In practice, reliability concepts are only applied to structural design. The requirements for design of machinery are generally limited to an adaptation of ASD. The following statement is made in the Article 1.3, Design Philosophy: "The design of bridge machinery in the United States is based on allowable working stress design, therefore, this specification follows the accepted industry design practice in this regard. As of this writing (2006), reliability-based design at the strength limit state is not possible given the dearth of necessary data.

53 The resistance of components and connections is determined, in many cases, on the basis of inelastic behavior, although the force effects are determined by using elastic analysis. This inconsistency is common to most current bridge specifications as a result of incomplete knowledge of inelastic structural action." An exception, where RBM is applied is in the use of L-10 life for bearings. Design of hydraulic systems for movable bridges is based on current practice (NFPA standards for example) at the time of publication and is not reliability based. Similarly, electrical system design follows the practices of standards that were not reliability based at the time such as NEC, IEEE and NEMA. 3.3 Use in NCHRP 12-112: A thorough review of the document was performed, and updates made where appropriate. 4. Key Words and Phrases: See Table 3 TABLE 3 – Key Words and Phrases Key Word Page Comments Availability N Component Failure 6-37 Criticality 3-13 Critical element failure Durability 6-3, 6-13(2), 6-21, 6-25(3), 7-13, A-3, A-8 Surface durability, fatigue, gear design Duty Cycle 7-5, 7-20(2), 8-8, 8-20(2), 8-28(2) Continuous duty / intermittent (hydraulic components) Fail Safe 6-40(2), 7-15, 7-18, 7-19 Failure Frequency N Failure Intensity N Failure Mode 4-2, 4-7, 6-1(2), 6-2, 6-14, 6-15, 7-16, 8-20 FMEA N Failure Modes Effects and Criticality Analysis (FMECA) N Failure Rate N Failure Tolerance N Fatigue Failure 6-4, 6-15, 6-16, 6-17, 6-18, 6-21 Fault Tree N Life (lifetime, B10 life, L10 life) 1-7, 1-8(2), 2-1(definition), 2- 6(3), 6-2(L-10 definition), 6-4, 6- 11(2), 6-23, 6-27, 6-29, 6-32(3), 7-2, 7-12, 7-15, 8-28(2), 8-31, A-7 Design life, design life factor, life factor, expected life, finite life, L- 10 Life, service life Mean Time N Mean Time Between Failures (MTBF) N Mean Time to Failure (MTTF) N Mean Time to Repair (MTTR) N Probability 2-2, 3-2, 3-19, 3-20, 4-1, 4-4, 4-5 Referenced to seismic design, vessel impact

54 TABLE 3 – Key Words and Phrases Key Word Page Comments Probability Risk Assessment N Redundancy 1-1, 1-6(4), 1-8, 1-9, 3-11, 3-14, 4-6, 7-7, 7-10, Reliability, Reliability Factor, Reliability-Based Design 1-1, 1-5, 2-7, 6-2(2), 6-3, 6-4, 6- 12(2), 6-23(3), 6-32, 6-56, 6-61, 8-13, 8-20, A-7(3) Reliability factor used in fatigue design, gear design Yield Failure 6-2, 6-26 ANSI/ABMA 11:2014 Load Ratings and Fatigue Life for Roller Bearings 1. Document Information Document Reviewed: ANSI/ABMA 11:2014 Load Ratings and Fatigue Life for Roller Bearings Publisher: ABMA Published Date of Document: 2014 Initial Date: Revision of ANSI/ABMA 11:1990 Latest Version: 2014 2. General Description of Document: From 1.1, Purpose of Standard: "This standard specifies the method of calculating the basic dynamic load rating of rolling bearings within the size ranges shown in the relevant ANSI/ABMA standards, manufactured from contemporary, commonly used, good quality hardened bearing steel in accordance with good manufacturing practice and basically of conventional design as regards the shape of rolling contact surfaces." "This standard also specifies the method of calculating the basic rating life, which is the life associated with 90% reliability, with commonly used high quality material, good manufacturing quality and with conventional operating conditions. In addition, it specifies the method of calculating adjusted rating life, in which various reliabilities, special bearing properties and specific operating conditions are taken into account by means of life adjustment factors."

55 3. Applicability to NCHRP 12-112 3.1 Components or Systems Covered: Rolling element bearings of the typical sizes and configurations used in bridge machinery systems such as trunnion bearings, drive/gear shaft bearings, and drive and auxiliary system components such as speed reducers. 3.2 Reliability-Based Methodology: The basis of determining bearing ratings in this standard is reliability. Bearing life or basic rating life, is determined as a function of basic dynamic load rating, which is generally limited by fatigue. From Article 1.2, Life Criterion, "In most applications the fatigue life is the maximum useful life of a bearing". Basic Static Load Rating is determined from deformation limits and is applied using a factor of safety (varying from 1.5 to 4). Definitions: Basic Rating Life, L10: The time at which 10% of a bearing population operating under the same conditions will have failed and 90% will have survived. The life is associated with a 10% probability of failure by the time calculated. Adjusted Rating Life, Lna: The rating life obtained by adjustment of the basic rating life for a desired reliability level, and/or special bearing properties, and/or specific operating conditions. Reliability: For a group of apparently identical rolling bearings, operating under the same conditions, the percentage of the group that is expected to attain or exceed a specified life. Basic Static Radial Load Rating C0r: Static radial load which corresponds to a calculated contact stress at the center of the most heavily loaded rolling element/raceway contact of 4,000 MPa (580,000 psi). NOTE: For this contact stress, under static load, a total permanent deformation of rolling element and raceway occurs which is approximately 0.0001 of the rolling element diameter. 3.3 Use in NCHRP 12-112: This standard is appropriate for reference in AASHTO LRFD as a means of establishing reliability of roller bearings. The basic rating life, L10, is a useful parameter for bearings subject primarily to dynamic conditions. Basic Static Load Rating is applicable for bearings subject to static load conditions, such as trunnion bearings. The methodology for rating roller manufactured bearings is standardized for all users. The current approach for use with movable bridges maintains the industry-standard approach (with a few unique modifiers). Integration with the new RBM for machinery was not warranted, as it would likely cause confusion and possible conflict.

56 4. Key Words and Phrases: See Table 4 Table 4 – Key Words and Phrases Key Word Page Comments Availability N Component Failure N Criticality N Cycles to Failure N Durability N Duty Cycle N Fail Safe N Failure Criteria N Failure Definition Variation N Failure Frequency N Failure Intensity N Failure Mode (failure definition) 12, 18 FMEA N Failure Modes Effects and Criticality Analysis (FMECA) N Failure Rate N Failure Tolerance N Fatigue Life 1 (3), 7, 20, 23 Fault Tree N Life (lifetime, B10 life, L10 life, Life Factor) 1, 2, 3, 4, 11, 18, 20, 21, 23 Life adjustment factors, adjusted rating life, basic rating life, rating life Mean Time N Mean Time Between Failures (MTBF) N Mean Time to Failure (MTTF) N Mean Time to Repair (MTTR) N Pitting Life Probability 3, 4, 22 Probability of failure Probability Risk Assessment N Redundancy N Reliability 1, 3, 21 Weibull probability N AGMA 2001-D04 Fundamental Rating Factors and Calculation Methods for Involute Spur and Helical Gear Teeth 1. Document Information Document Reviewed: AGMA 2001-D04 Fundamental Rating Factors and Calculation Methods for Involute Spur and Helical Gear Teeth Publisher: American National Standard / American Gear Manufacturer's Association Published Date of Document: 2004 Initial Date: 1986(draft), 1988(approved) Latest Version: 2004

57 2. General Description of Document: This standard provides a method by which different gear designs can be theoretically rated and specifies a method for rating the pitting resistance and bending strength of spur and helical involute gear pairs. Detailed discussions of factors influencing gear survival and calculation methods are provided. The standard presents general formulas for rating and pitting resistance and bending strength of spur and helical involute gear teeth. The purpose is to establish a common base for rating various types of gears for differing applications, and encourage uniformity and consistency within the gear industry. Factors included in the standard: Accuracy, manufacturing process, and the latest version has been expanded to include various steel quality grades, and a new rim thickness factor (Kb). Scuffing (scoring) resistance was added as an annex. 3. Applicability to NCHRP 12-112 3.1 Components or Systems Covered: Internal and external spur and helical involute gear teeth operating on a parallel axis 3.2 Reliability-Based Methodology: RBM is the basis of the empirical data used in Annex E (Gear Material Fatigue Life). 3.3 Use in NCHRP 12-112: This standard is appropriate for reference in AASHTO LRFD as a means of establishing reliability of gears. Both open gearing and enclosed gearing (speed reducers) are currently designed based on AGMA standards. AGMA utilizes a Service Factor in design and application requires MHBDS load factors to be unity so that the two standards don’t conflict. Integration with the new RBM for machinery was not warranted, as it would likely cause confusion and possible conflict. 4. Key Words and Phrases: See Table 5 Table 5 - Key Words and Phrases Key Words Page Comments Availability N Component Failure N Criticality N Cycles to Failure 51 Annex E- cycles graphed for different materials Durability N

58 Table 5 - Key Words and Phrases Key Words Page Comments Duty Cycle 12(2) When transmitted load is not uniform, consider peak and intermediate loads Fail Safe N Failure Criteria 37 Used in Figure 17 for pitting resistance Failure Definition Variation 52 Used in Annex E for fatigue lift implications for different material variations Failure Frequency N Failure Intensity N Failure Mode (failure definition) 8 Gear failure is subjective, and covered in AGMA 1010 FMEA N Failure Modes Effects and Criticality Analysis (FMECA) N Failure Rate N Failure Tolerance N Fatigue Life 49(6), 50, 51, 52, 53(3) Annex E provides additional information concerning the assessment of fatigue life for gears Fault Tree N Life (lifetime, B10 life, L10 life, Life Factor) v(2), 4, 6(2), 8, 9, 15, 23, 35, 36, 43, 44, 49 References to fatigue service life, gear service life, bearing service life Mean Time N Mean Time Between Failures (MTBF) N Mean Time to Failure (MTTF) N Mean Time to Repair (MTTR) N Pitting Life 51 Probability 38(2) Statistical distribution of failures used to modify the allowable stresses in material used Probability Risk Assessment N Redundancy N Reliability 5(2), 6, 10, 23, 36, 38(3), 43(2), 44, 52 Page 5 states that allowable stress numbers are based on 10 to the 7th power cycles and 99 percent reliability; standard uses reliability factor for design. Page 38, 43 discusses material reliability.

59 Table 5 - Key Words and Phrases Key Words Page Comments Weibull probability 51 Related to pitting resistance BS 6786-1 Requirements for the Design of Movable Parts of Structures – Part 1: Movable Bridges (Dutch Standard) 1. Document Information Document Reviewed: BS 6786-1 Requirements for the Design of Movable Parts of Structures – Part 1: Movable Bridges. Dutch Standard, Publisher: Royal Netherlands Standardization Institute (NEN) Published Date of Document: August 2017 (machine and supplemental manual translation from Dutch to English) Initial Date: 2001 Latest Version: August 2017 2. General Description of Document: This standard provides technical rules for assessing the structural safety of the mechanical equipment of movable bridges. 3. Applicability to NCHRP 12-112 3.1 Components or Systems Covered: The standard covers machinery and hydraulic systems. Electrical systems are not covered except for motors. 3.2 Reliability-Based Methodology: The standard is based on RBM. In addition to the provisions included in the standard are references to other RBM standards, such as BS EN 1990, Eurocode Basis of Structural Design. However, unlike most other documents reviewed, BS 6786-1 addresses specific requirements for machinery and hydraulic systems for movable bridges. The following are some definitions from Article 1.3, Terms and Definitions: Reliability: possibility that a movable bridge may perform a required function under prescribed conditions for a predetermined time. Non-operable: Part of the planned unavailability due to a wind speed greater than that of the mechanical equipment is designed. NOTE Not included in non-operable foreseeable unavailability for maintenance and unforeseen unavailability due to interference etc. 0 Note that these are copied from a translated version of the document and may contain translation errors.

60 Serviceability limit state: boundary condition relating to the functioning of the structure or parts thereof under conditions over which the compliance usability requirements of this standard no longer like the comfort of people, the appearance of the building, etc. Ultimate limit state: state associated with structural failure or uncontrolled movement of the bridge. There are several concepts covered in this document that represent an expansion of RBM design to specific aspects of movable bridges. These include "Bridge Availability", including the importance of the waterway and nominal bridge clearance, wind design specifically developed for movable bridges including consideration of locality and bridge height and partial factors. Loads that impact the sizing of the prime mover are addressed, including partial factors. In addition, loads used to design drive machinery are addressed for both mechanical and hydraulic systems, including partial factors. The standard lists limit states, load factors and resistance factors for a number of design scenarios. Loads include dead loads (including parameters for variable deck weight), friction, inertia, wind, braking, and vibration (dynamic effects on dead load). Resistance considerations include material factors for various steels, serviceability, strength and fatigue. Gear design follows ISO 6336, an approach similar to AGMA standards. Other components are also addressed such as couplings, wire ropes and bearings. Lists the design life of mechanical equipment and hydraulic cylinders as 50 years, hydraulic units and electrical equipment as 25 years and control systems as 15 years (Page 33). Reliability index is a defined variable, but it is not used in the text to any extent. It may be embedded in some of the formulas that did not translate well. 3.3 Reference Documents: To obtain a better understanding of this document the research team investigated the reference documents listed in the bibliography. Below is a summary of search on relevant documents from the bibliography. “Heron” 1964 Vol. 12 no1, Stevin Laboratory report no. 6-63-8. Document was found here: http://heronjournal.nl/archive.html, and machine translated to English. The document talks about ROTATING CONSTRUCTION PARTS. VDI 223:2003 Verein Deutscher Ingenieure, Systematic Berechnung hochbeanspruchter Schraubenverbindungen. VDI 2230:2003’ is a German specification entitled ‘Systematic calculation of high duty bolted joints’ released in 2003. This is a bilingual version in German and English. A. Vrouwenvelder, P. Waarts, and P. van Stallduien, TNO report B90-342, Nov. 1990, Wind Load on the movable bridges. Available and downloaded from TU Delft Library (https://repository.tudelft.nl/view/tno/uuid:8de31e81-0f75-4dd4-8a49-f88ed0e79a9f/ ) in Dutch, machine translated to English. The document presents research done on the dynamic behavior of movable bridges with horizontal rotation axis under wind load. Two bridges, with regular and irregular motor were considered. The dynamic behavior of a

61 bridge was determined by a simple computer model, where wind loads were randomly simulated, taking into account uncertainties of: a. Hourly average wind speed, V, b. Ambient condition, E, c. The wind pressure coefficient, ct, d. Gust factor, G, Wind load components’ uncertainties were reflected by partial safety factors, γ=X*/Xn (Value of X at design point per nominal value of X). The load components’ statistical distributions and variations are reported in section 3.3 and refer to work done by Strating J. “Partiele veilighidsfactoren voor de TGB 1986”. Protech International BV, Scheidam, August 1985. In section 3.2 of the report, three safety classes are introduced, depending on consequences of collapse. Classes 1-small, 2-mean, 3-big, have reliability indices ranging from 2.3 to 2.6 for dominant wind load in the load combination and from 3.3-3.6 when wind is not a dominant load in the load combination. These values of safety levels correspond with provisions of TGB 1990 – General Section, which is a Dutch equivalent of Eurocode 1990. The combinations of loads consisting of wind load, acceleration, imbalance, braking force during normal operation and stopping were analyzed. 3.4 Target Reliability in NEN 6786 The research team researched the origins of NEN 6786 to better understand the reliability indices of the current version. The following summarizes the findings. 3.4.1 NEN 6786:2001+A1 2002 The release 2001 of NEN 6786 code with a further appendix from 2002, implemented a semi-probabilistic calculation method, with minimum reliability indices (β): - Ultimate Limit State, when Wind Load controls: β=2.6, - Ultimate Limit State, if other loads controls: β=3.6, - Serviceability Limit State: β=0.5. These safety levels were earlier specified in the TNO report B90-342 from 1990 that the code refers to. TNO report B90-342: The reliability indices related to ultimate limit states developed in TNO B90-342 were published in November 1990. This document, available only in Dutch language, is a report of a study of the wind loads on movable bridges and distinguished three safety classes, depending on the consequences of collapse. Collapse consequence classes 1-low, 2-medium, 3-high, had assigned reliability indices ranging from 2.3 to 2.6 for dominant wind load in the load combination and from 3.3 to 3.6 when other loads control. This report also recommends considering

62 the highest values of reliability indices for collapse consequence class 3, and mainly focuses on the case with wind load controlling. For the serviceability limit state, the report brings up the reliability index of 1.8 from TGB 1990 - General Section, which corresponds to probability of failure of 0.036. Although, the report mentions that taking into consideration the nature of movable bridge operation, higher probability of failure shall be allowed and proposes the reliability index β=0.5, with corresponding probability of failure of 0.3, that was implemented in 2001 release of NEN 6786. 3.4.2 NEN 6786:2017 Current release of NEN 6786 does not provide direct information on the reliability indices incorporated in the provisions of the code, however it clearly exhibits traces of probabilistic-based design approach by distinguishing various limit states and presentation of partial safety factors. A Dutch copy of the standard that was machine translated to English was investigated for the references with more information on the incorporated reliability indices. In ‘normative references’ section, a reference to Eurocode EN 1990 with appropriate Annexes is made. The EN 1990 specifies general rules that apply to all the Eurocodes and sets safety levels that are incorporated throughout all the parts of Eurocodes. For better understanding of Eurocodes, their structure and intercorrelation below section is provided. 3.4.3 About Eurocodes and implementation of Dutch standards to Eurocode format The following text is intended to clarify the structure, function and application of the Eurocodes within member states of European Union (EU). Quotation from http://eurocodes.jrc.ec.europa.eu available on 07/03/2018: “The EN Eurocodes are expected to contribute to the establishment and functioning of the internal market for construction products and engineering services by eliminating the disparities that hinder their free circulation within the Community. Further, they are meant to lead to more uniform levels of safety in construction in Europe. The EN Eurocodes are the reference design codes. After publication of the National Standard transposing the Eurocodes and the National Annexes, all conflicting standards shall be withdrawn. It is mandatory that the Member States accept designs to the EN Eurocodes. The EN Eurocodes apply to structural design of buildings and other civil engineering works including: • geotechnical aspects; • structural fire design; • situations including earthquakes, execution and temporary structures.

63 For the design of special construction works (e.g., nuclear installations, dams, etc.) other provisions than those in the EN Eurocodes might be necessary. The EN Eurocodes cover basis of structural design (EN 1990); actions on structures (EN 1991); the design of concrete (EN 1992), steel (EN 1993), composite steel and concrete (EN1994), timber (EN 1995), masonry (EN 1996) and aluminum (EN 1999) structures; together with geotechnical design (EN 1997); and the design, assessment and retrofitting of structures for earthquake resistance (EN 1998). The EN Eurocodes are reference documents. The Member States of the EU and the European Free Trade Association recognize that EN Eurocodes serve as reference documents for the following purposes: • as a means to prove compliance of building and civil engineering works with the basic requirements of the Construction Products Regulation Construction Products Directive, particularly Basic Requirement 1 "mechanical resistance and stability" and Basic Requirement 2 "Safety in case of fire"; • as a basis for specifying contracts for construction works and related engineering services; • as a framework for drawing up harmonized technical specifications for construction products (ENs and ETAs). 3.4.4 National Implementation of the EN Eurocodes Member states, national authorities in liaison with NSBs and other relevant parties, should design and set-up an appropriate Implementation Plan for the Eurocodes in their country. As part of that plan, national authorities and national standards bodies, when an EN Eurocode Part is made available, should: • translate the Eurocode Part in authorized national languages; • set the Nationally Determined Parameters to be applied on their territory; • publish the National Standard transposing the EN Eurocode and the National Annex, containing the national choice on the NDPs and reference to non- contradictory complementary information, and notify the European Commission; • adapt, as far as necessary, their national provisions so that the EN Eurocode Part can be used on their territory: as a means to prove compliance of construction works with the national requirements for "mechanical resistance and stability" and "resistance to fire" as a basis for specifying contracts for the execution of public construction works and related engineering services; • promote training on the Eurocodes. During the Coexistence Period, both the National Standard transposing the EN Eurocode and any existing national standard can be used. At the end of the

64 Coexistence Period of the last EN Eurocode Part of a Package, the National Standards Bodies should withdraw all conflicting National Standards.” 3.4.5 EN 1990 – Reliability classes (RC) and minimum reliability indices The Eurocode 1990 provides two informative annexes (Annex B and C) that describe ‘Management of Structural Reliability’ and ‘Basis for partial factor design and Reliability Analysis’. In Annex B, three consequences classes (CC1-CC3) are introduced that correspond to three reliability classes (RC1-RC3). See tables following: Table B1 – Definition of consequences classes Table B2 – Recommended minimum values for reliability index β (ultimate limit states) Reliability Class Minimum values for β 1 year reference period 50 years reference period RC3 5,2 4,3 RC2 4,7 3,8 RC1 4,2 3,3 NOTE: A design using EN 1990 with partial factors given in Annex A1 and EN 1991 to EN a999 is considered generally to lead to a structure with a β value greater than 3,8 for a 50 year reference period. Reliability classes for members of the structure above RC3 are not further considered in this annex, since these structures each require individual consideration. The reliability indices shown in table above set minimum safety levels that all member states shall have incorporated in their national standards for the uniformity of safety levels across the member states. Each member state, by appropriate national directives must precisely specify a certain reliability class to be incorporated in their national standards. Consequences Class Description Examples of buildings and civil engineering works CC3 High consequences for loss of human life, or economic, social or environmental consequences very great Grandstands, public buildings where consequences of failure are high (e.g., a concert hall) CC2 Medium consequences for loss of human life, or economic, social or environmental consequences considerable Residential and office buildings, public buildings where consequences of failure are medium (e.g., an office building) CC1 Low consequences for loss of human life, or economic, social or environmental consequences small or negligible Agricultural buildings where people do not normally enter (e.g., storage buildings), greenhouses

65 3.4.6 Richtlijn Ontwerp Kunstweken ROK 1.0 (‘Guideline Design Artworks GDA 1.0’) As clarified in above section, each member state must release appropriate guidelines regarding the implementation of Eurocodes in national practice. A document ‘Richtlijn Ontwerp Kunstwerken ROK 1.0’ (‘Guideline Design Artworks GDA 1.0’) released in 2011 by the Dutch Ministry for Transportation talks about the implementation of Eurocodes in Dutch national practice, development of National Annexes, and relating national codes with Eurocodes. This document was translated to English and thoroughly researched for the traces linking NEN 6876 with EN 1990. Summary of findings, along with quotations is presented below. The date of April 1st, 2012 is specified as an effective date of Eurocodes designation “as standards with which the constructive safety must be demonstrated”. In section 4.4 entitled ‘Application for movable bridges’ under section ‘4. Eurocode – Principles of the structural design’ one can read: “In closed position, the movable bridge must meet the requirements in NEN-EN 1990 + NB (+ associated ROK parts). The movable bridge must meet the same requirements as a corresponding "fixed" bridge including the choice of the effect class. In the limit state "overloading" / "overloading transmission" (mechanical equipment), all loads must be handled in accordance with NEN 6786 and the load combinations must be based on formula 6.10 of the NEN-EN 1990, for consequence class 2 for the own weight with a load factor of 1.30 instead of 1.5 (for other consequence classes see paragraph below). This applies to tables 11, 12, 13, 14, 15 and 17 of NEN 6786. In accordance with NEN-EN-1990 Annex B, Table B3, the load factors for "overloading" / "overloading" (mechanical equipment) in Chapter 8 of NEN 6786 must be multiplied by the factor KFI. The RC class of the mechanical equipment must be equated with the steel superstructure. Explanation: In the NEN-EN 1990 / NB, the values of the load factors, including the factor KFI, are given in Table NB.13 for each consequence class. For the connection of the NEN 6786 to the Eurocode, however, the KFI factors included in Appendix B, Table B3 must still be used at this point. For checking the permanent location of the bridge, reference is made to NEN 6786. The mechanical equipment of movable structures (movable bridges, locks, barges, etc.), including the above-mentioned modifications, must be tested against the NEN 6786 (structural aspects) and NEN 6787 (safety). Mechanical equipment is understood to mean the entirety of drive mechanisms (mechanical and hydraulic), securing devices and other mechanical components, such as pivot points, rope pulleys, guides, raceways and the like.” In the quoted text above a consequence class 2 specified in Dutch version of EN 1990 (NEN-EN 1990) is brought up and clearly specifies a corresponding reliability class RC2 that was used in the 2017 version of NEN 6786 code (NEN 6786:2017).

66 3.4.7 Conclusions In the Table B2 in EN 1990, the reliability index for return period of 50 years for reliability class RC2 is equal to 3.8 and per ‘Richtlijn Ontwerp Kunstwerken ROK 1.0’ this is the value that is incorporated in NEN 6876:2017. It has to be noted, that reliability index of β=3.8 per NEN 6786:2017 introduces higher safety level as opposed to β=3.6 per NEN 6786:2001+A1 2002. 3.5 Use in NCHRP 12-112: This standard is similar in scope to AASHTO Movable, but more closely follows an RBM approach. Detailed review of this document on a system and component level was performed to determine areas that were used as a guide or reference in updating the AASHTO LRFD Movable. Particularly helpful areas included the following: • "Bridge Availability", including the importance of the waterway and nominal bridge clearance • Wind design specifically developed for individual movable bridges including consideration of locality and bridge height • Partial Factors – partial factors presented for dead loads, variable deck weight, wind loads, resistance of sections, resistance of materials, fatigue, sliding resistance, high strength bolts. • Loads that impact the sizing of the prime mover, including partial factors. • Loads used to design drive machinery for both mechanical and hydraulic systems, including partial factors. 4. Key Words and Phrases: See Table 6 Table 6 - Key Words and Phrases Key Word Page Comments Availability 14, 30 References are to what conditions a bridge should be operable (e.g., wind speed) Inherent Availability (Ai) N Operational Availability (AO) N See availability Component Failure (Failed Component) N Criticality N Durability 33, 146 Duty Cycle N Fail Safe N Failure Frequency N Failure Intensity N Failure Mode N

67 Table 6 - Key Words and Phrases Key Word Page Comments FMEA N Failure Model N Failure Modes Effects and Criticality Analysis (FMECA) N Failure Rate N Failure Tolerance N Fault Tree N Life (lifetime, B10 life, L10 life, life cycle) 7, 8, 30, 32(3), 33(4), 66, 75, 123(6), 148(2), 159, 16092), 161, 164, 166, 169(2), 187, 191 Design life, design service life, bearing life Mean Time N Mean Time Between Failures (MTBF) N Mean Time to Failure (MTTF) N Mean Time to Repair (MTTR) N Probability N Probability Risk Assessment N Redundancy N Reliability 13, 22, 30, 77, 154(2) Reliability Index is a defined variable (Page 22) Reliability Centered Maintenance (RCM) N BS EN 1090-2: Execution of Steel Structures and Aluminum Structures, Part 2: Technical Requirements of Steel Structures 1. Document Information Document Reviewed: BS EN 1090-2: Execution of steel structures and aluminum structures Part 2: Technical requirements of steel structures Publisher: British Standard published under the authority of the Standards Policy and Strategy Committee Published Date of Document: 2008 Initial Date: 2008 Latest Version: NA (if different from document reviewed)

68 2. General Description of Document: This standard provides technical requirements for fabrication and erection of steel structures. The standard is in conformance with the reliability principles defined in EN 1990:2002 Eurocode – Basis of structural design. The approach defines Execution Classes as a means of differentiating levels of reliability. Execution Classes are determined as a function of Consequence Classes and Hazards. Consequence Classes are established for three levels of consequence (very great, considerable, or small or negligible) for loss of human life, or economic, social or environmental consequences. Hazards are established for service categories and production categories. 3. Applicability to NCHRP 12-112 3.1 Components or Systems Covered: The standard covers steel structures, specifically buildings, bridges including plated or latticed components. 3.2 Reliability-Based Methodology: The standard is founded on RBM although the terminology is different, following Eurocode. 3.3 Use in NCHRP 12-112: The standard offered little information relevant to the project, primarily in the form of understanding the Eurocode approach to reliability-based design. No information specific to movable bridge machinery or electrical systems was provided. 4. Key Words and Phrases: See Table 7 Table 7 - Key Words and Phrases Key Word Page Comments Availability 71 Component Failure N Criticality N Durability 10, 63,75, 79(2) Duty Cycle N Fail Safe N Failure Frequency N Failure Intensity N Failure Mode N FMEA N Failure Modes Effects and Criticality Analysis (FMECA) N Failure Rate N Failure Tolerance N

69 Table 7 - Key Words and Phrases Key Word Page Comments Fault Tree N Life (lifetime, B10 life, L10 life) 24, 35, 80(3), 81, 101, 102, 172, 173, 175, 180, 181 Mostly related to coating protection systems; design life for structures Mean Time N Mean Time Between Failures (MTBF) N Mean Time to Failure (MTTF) N Mean Time to Repair (MTTR) N Probability N Probability Risk Assessment N Redundancy N Reliability Forward (2), 11, 111(2) Related to Execution Classes Canadian Highway Bridge Design Code CSA S6-14 with emphasis on Section 13 – Movable Bridges 1. Document Information Document Reviewed: CSA S6-14 Canadian Highway Bridge Design Code, Chapter 13 Movable Bridges Publisher: CSA Group Published Date of Document: 2014 Initial Date: 2006 (as CSA S6) Latest Version: NA (if different from document reviewed) 2. General Description of Document: This standard establishes requirements for design, evaluation and rehabilitation of fixed and movable bridges. For this review, only the provisions of Chapter 13, Movable Bridges were examined in detail. 3. Applicability to NCHRP 12-112 3.1 Components or Systems Covered: Chapter 13 specifies requirements for conventional movable highway bridge (bascule, including rolling lift, swing, and vertical lift) and the components common to them. There are

70 sections covering materials, structural analysis and design, mechanical systems, hydraulic systems and electrical systems. 3.2 Reliability-Based Methodology: RBM is not explicitly discussed, however, the standard does cover use of reliability as a factor in fatigue design. B10 service life per ABMA is noted for anti-friction bearings and L10 life for rolling element bearings in speed reducers. References are made to other standards which may include RBM, such as AGMA, ABMA, and IEEE. Redundancy in electrical power systems is mentioned regarding use of internal combustion engineers as prime movers for hydraulic systems for emergency operation (13.8.8). Redundancy of hydraulic pumps is required unless a backup system is provided for emergencies (13.8.14.2). 3.3 Use in NCHRP 12-112: The standard offered limited information relative to the project. 4. Key Words and Phrases: See Table 8 Table 8 - Key Words and Phrases Key Word Page Comments Availability 27(2), 400 No use is related to RBM Component Failure N Criticality N Durability Chapter 13 Movable Bridges - 572, 578, 579, 586 Duty Cycle 606, 646(2), 658 Fail Safe 614 Failure Frequency N Failure Intensity N Failure Mode 638 FMEA N Failure Modes Effects and Criticality Analysis (FMECA) N Failure Rate N Failure Tolerance N Fault Tree N Life (lifetime, B10 life, L10 life) 571, 590, 623, 625 Mean Time N Mean Time Between Failures (MTBF) N Mean Time to Failure (MTTF) N Mean Time to Repair (MTTR) N

71 Table 8 - Key Words and Phrases Key Word Page Comments Probability N Probability Risk Assessment N Redundancy 641, 643 Reliability 571, 586, 592, 608, 631 CMMA 70: Specifications for Top Running Bridge and Gantry Type Multiple Girder Electric Overhead Traveling Cranes 1. Document Information Document Reviewed: CMMA 70: Specifications for Top Running Bridge & Gantry Type Multiple Girder Electric Overhead Traveling Cranes Publisher: Crane Manufacturers Association of America, Inc. Published Date of Document: 2004 Initial Date: 2000 Latest Version: 2004 2. General Description of Document: These specifications cover top running and gantry type multiple girder electric traveling cranes. The specifications include guidelines for structural, mechanical and electrical systems and components. The specification outlines six different classes of cranes. The classes range from Class A (Standby or Infrequent Service) to Class F (Continuous Severe Service). 3. Applicability to NCHRP 12-112 3.1 Components or Systems Covered: The components or systems covered include: structural components associated with the crane, load blocks, overload limit devices, hoisting ropes, sheaves, drums, gearing, bearings, brakes, bridge drives, shafting, couplings, wheels, bumpers, stops, motors, brakes, controllers, resisters, protective features, limit switches. 3.2 Reliability-Based Methodology: A crane service class and mean effective load factor range can be determined based on load class and load cycles. In general, the guidelines apply factors to the load and loading conditions and strength design is based on allowable stresses and or endurance strengths.

72 3.3 Use in NCHRP 12-112: The specifications contained a vast amount of information related to cranes. However, the specifications applied to top running and gantry type multiple girder electric traveling cranes, which are not common on movable bridges. 4. Key Words and Phrases: See Table 9 Table 9 - Key Words and Phrases Key Word Page Comments Availability N Component Failure N Criticality N Durability 8, 33 (3), 37(4),38(7), 47, 49(3), 85 Is used to determine a level of service. Load factors are used to determine the durability of components. Used in AGMA calculations. Used for wheel sizing and material selection. A mean effective load is used in durability calculations to account for maximum and minimum loads. Duty Cycle 56, 59, 60, 61, 67, 86 The duty cycle listed in the specifications is used for motor and control selection. Fail Safe 84 The following definition is provided in the specifications: "A provision designed to automatically stop or safely control any motion in which a malfunction occurs." Failure Frequency N Failure Intensity N Failure Mode N FMEA N Failure Modes Effects and Criticality Analysis (FMECA) N Failure Rate N Failure Tolerance N Fault Tree N Life (lifetime, B10 life, L10 life) N Mean Time N Mean Time Between Failures (MTBF) N Mean Time to Failure (MTTF) N Mean Time to Repair (MTTR) N

73 Table 9 - Key Words and Phrases Key Word Page Comments Probability 10(2) Load probability and load spectrum are used to determine a mean load effective factor. Probability Risk Assessment N Redundancy N Reliability 11 Reliability is based on class of the crane, with Class F being the highest. DIN 19704 Hydraulic Steel Structures, Part 1: Design Analysis (1998) 1. Document Information Document Reviewed: DIN 19704 Hydraulic Steel Structures, Part 1: Design Analysis Publisher: German Institute for Standardization (DIN) Published Date of Document: May, 1998 Initial Date: 1958 Latest Version: Nov. 2014 (currently not available in English language translation) 2. General Description of Document: This standard provides specifications for design of hydraulic steel structures (flood gates, navigation gates) including structural steelwork, mechanical and electrical equipment. The document is also commonly used for movable bridge design in Germany. 3. Applicability to NCHRP 12-112 3.1 Components or Systems Covered: The standard covers steel structures, machinery, and hydraulic drives. 3.2 Reliability-Based Methodology: The standard is not based on RBM although there is mention of design life and/or service life, specifically for fatigue of steel structures, gearing and bearings. 3.3 Use in NCHRP 12-112: There was little application to NCHRP 12-112.

74 4. Key Words and Phrases: See Table 10 Table 10 - Key Words and Phrases Key Word Page Comments Availability N Component Failure N Criticality N Durability N Duty Cycle N Fail Safe N Failure Frequency N Failure Intensity N Failure Mode N FMEA N Failure Modes Effects and Criticality Analysis (FMECA) N Failure Rate N Failure Tolerance N Fault Tree N Life (lifetime, B10 life, L10 life) 5, 13, 19(2), 22(4), 23, 25 References to fatigue service life, gear service life, bearing service life Mean Time N Mean Time Between Failures (MTBF) N Mean Time to Failure (MTTF) N Mean Time to Repair (MTTR) N Probability N Probability Risk Assessment N Redundancy Reliability 11, 18 DIN 19704-1 Hydraulic Steel Structures, Part 1: Design Analysis (2014) 1. Document Information Document Reviewed: DIN 19704-1 Hydraulic Steel Structures, Part 1: Design Analysis Publisher: German Institute for Standardization (DIN) Published Date of Document: November 2014 (machine translated from German to English) Initial Date: 1958

75 Latest Version: November 2014 2. General Description of Document: This standard provides specifications for design of hydraulic steel structures (flood gates, navigation gates) including structural steelwork, mechanical and electrical equipment. The document is also commonly used for movable bridge design in Germany. 3. Applicability to NCHRP 12-112 3.1 Components or Systems Covered: The standard covers steel structures, machinery, and hydraulic drives. 3.2 Reliability-Based Methodology: With regards to structural design this standard follows RBM through reference to DIN EN 1990 (Eurocode). With regards to machinery, the use of RBM is less clear. There is mention of design life and/or service life, specifically for fatigue of steel structures, gearing and bearings. Design service life is specified for several elements, including 35 years for gear drives, electrical equipment and machine parts. Some of the referenced standards, such as those for gearing were published in 1987 and are unlikely to be based on RBM. Other referenced standards, such as those for roller bearings are newer and may be RBM based. The limited scope of review did not allow for detailed review of these references. Service life of ball screw and planetary roller screws are required to be based on a reliability factor fr=1. There are referenced to other standards regarding rating and life, such as DIN ISO 281, Rolling bearings - Dynamic load ratings and rating life and DIN ISO 3408-5, Ball screws - Part 5: Static and dynamic axial load ratings and operational lifetime. 3.3 Use in NCHRP 12-112: This specification included design service life for several elements that are used in movable bridges. Article 10:14 addressed factors for using manufacturer ratings for spherical plain bearings, an element not defined in the current AASHTO LRFD Movable. Both of these topics were found to be beyond the scope of the current project but are recommended for future research in Chapter 4 herein. 4. Key Words and Phrases: See Table 11 Table 11 - Key Words and Phrases Key Word Page Comments Availability N Inherent Availability (Ai) N Operational Availability (Ao) N

76 Table 11 - Key Words and Phrases Key Word Page Comments Component Failure (Failed Component) N Criticality N Durability N Duty Cycle 49(2) Fail Safe N Failure Frequency N Failure Intensity N Failure Mode N FMEA N Failure Model N Failure Modes Effects and Criticality Analysis (FMECA) N Failure Rate N Failure Tolerance N Fault Tree N Life (lifetime, B10 life, L10 life, life cycle) 23, 32(2), 36(2), 38, 39(3), 41, 46, 47 References to fatigue service life, gear service life, bearing service life Mean Time N Mean Time Between Failures (MTBF) N Mean Time to Failure (MTTF) N Mean Time to Repair (MTTR) N Probability 19 Probability Risk Assessment N Redundancy N Reliability 36 Reliability factor for ball screws and planetary roller screws Reliability Centered Maintenance (RCM) N F.E.M. 1.001: Rules for the Design of Hoisting Appliances 1. Document Information Document Reviewed: F.E.M. 1.001: Rules for the Design of Hoisting Appliances Publisher: Federation Europeenne de la Manutention Published Date of Document: 1998 Initial Date: 1962 Latest Version: 3rd Edition

77 2. General Description of Document: The document contains rules developed for application to the design of lifting appliances or part of lifting appliances. The purpose of the rules is to determine the loads and combinations of loads when designing hoisting appliances and for designing the components and the systems associated with them. They are also used to establish strength and stability conditions. 3. Applicability to NCHRP 12-112 3.1 Components or Systems Covered: The components and systems covered include the structural, mechanical and electrical components and systems associated with lifting appliances. The mechanical components and systems similar too movable bridges include: wire ropes, drums, sheaves, shafts, bearings, gearing, wheels and rail. The electrical components and systems similar too movable bridges include: power, control, wiring, motors, limit switches and safety devices. 3.2 Reliability-Based Methodology: The rules use a class of utilization and a load spectrum classification to classify mechanisms as a whole in one of eight groups. The groups include M1 through M8. • Class of Utilization for a mechanism is based on the duration of use. • Load Spectrum for a mechanism is based on the magnitude of loads acting during is duration of use. In general, the guidelines apply factors to the load and loading conditions and strength design is based on allowable stresses with associated safety coefficient for the case of loading and or the fatigue & endurance strengths. 3.3 Use in NCHRP 12-112: The document contained a detailed discussion of the factor of safety for wire ropes. Included was the “class of utilization and load spectrum” method of evaluation. This methodology is quite different than the RBM ultimately used. However, because wire rope selection remains mostly isolated, it is recommended (in Chapter 4 herein), that this should be a topic of future research. 4. Key Words and Phrases: See Table 12 Table 12 - Key Words and Phrases Key Word Page Comments Availability N Component Failure N

78 Table 12 - Key Words and Phrases Key Word Page Comments Criticality N Durability N Duty Cycle 5-9 The overload factor for a particular duty cycle can be calculated as a function of active periods, idle periods and the thermal time constant. Fail Safe N Failure Frequency N Failure Intensity N Failure Mode N FMEA N Failure Modes Effects and Criticality Analysis (FMECA) N Failure Rate N Failure Tolerance N Fault Tree N Life (lifetime, B10 life, L10 life) Intro 1-4, TOC 4-1, 4-14(3), 4-15, 4-20, 4- 23, 4-33(5), 4- 34(4), 4-36(2), 4-37(3), 4- 38(2), 7-23 Used to define how long on average a system or components will last under certain conditions. Mean Time N Mean Time Between Failures (MTBF) N Mean Time to Failure (MTTF) N Mean Time to Repair (MTTR) N Probability 2-32, 2-36, 3- 3, 3-27, 4-7 Used to determine if and or amount the calculated stress is exceeded by applying an amplifying coefficient. Used as a % of if a part or materials will survive Probability Risk Assessment N Redundancy N Reliability 5-12, 5-13, 9- 23 Term used as a topic of consideration of if a system is performing consistently well. The rules also reference: 1986, "General Principle on Reliability for Structures".

79 352 IEEE Guide for General Principles of Reliability Analysis of Nuclear Power Generating Systems and Other Nuclear Facilities 1. Document Information Document Reviewed: 352 IEEE Guide for General Principles of Reliability Analysis of Nuclear Power Generating Systems and Other Nuclear Facilities Publisher: Institute of Electronics Engineers, Inc. (IEEE) Published Date of Document: Dec. 7, 2016 Initial Date: 1987 Latest Version: IEEE Std 352-2016 2. General Description of Document: This document contains general reliability and availability analysis methods that can be applied to the electrical elements of structures, systems, and components in nuclear power generating stations and other nuclear facilities. It provides quantitative principles for analysis of the effects of component failures on safety system reliability. Chapter 3 provides a list of definitions, including some less common in other standards such as human error probability, steady-state availability, transient availability, and wearout period. Chapter 4 has a discussion on the human factor. C1.6, Spare parts acquisition, discusses minimizing downtime by having spare parts available. 3. Applicability to NCHRP 12-112 3.1 Components or Systems Covered: Focus of document is on electrical equipment, systems and components. The definitions and description of how RBM is applied to electrical systems of nuclear facilities may provide a basis for or guidance for movable bridges. The use of FMEA is presented and may be of application in AASHTO. 3.2 Reliability-Based Methodology: The document and contents are RBM. Reliability is addressed in both qualitative analysis and quantitative analysis.

80 3.3 Use in NCHRP 12-112: There was not much information in this standard relative to movable bridges that was not covered in IEEE 493-2007. One item that underwent a more detail look is the FMEA ranking scales, a severity ranking scale as a means of differentiating the significance of failure. Some basic concepts of the FMEA approach were utilized by Auburn in developing the RBM with data mined from the owner surveys. 4. Key Words and Phrases: See Table 13 Table 13 - Key Words and Phrases Key Word Page Comments Availability 2(2), 8(2), 10(2), 11(2), 12, 13(4), 14(8), 15(2), 17(3), 18(2), 19(2), 20, 23, 34, 40(2), 42(6), 43(7), 54(3), 55(4), 57, 59(3), 60(7), 61(4), 62(2), 63(3), 64(2), 65(6), 73, 75, 76(3), 84, 86(2), 92(2), 93, 99(6), 101, 104(3), 105(3), 125, 131(2), 135, 141 Inherent Availability (Ai) N Operational Availability (Ao) N Component Failure (Failed Component) 12, 18, 20, 31, 33, 34, 52, 54, 55(2), 59, 61, 63, 73, 76(3), 78(2), 86(2), 87, 91, 98(2), 105(4), 124(2), 126, 127, 136, 140 Criticality 17, 23, 102 Durability N Duty Cycle N Fail Safe 20 Failure Frequency N Failure Intensity N Failure Mode 9(9), 11(2), 15(2), 16(4), 17(4), 18(2), 19(2), 20(4), 22(2), 23(12), 24(5) 32, 33, 38(4), 74(2), 78(5), 79(2), 80(4), 87, 102(2), 104, 105(7), 107(7), 108(4), 109(3), 110(10), 111(4), 112(5), 113(2), 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124(20), 125(2), 126(2), 127,

81 Table 13 - Key Words and Phrases Key Word Page Comments 128, 129(3), 130, 131(2), 133, 135 FMEA 9(9), 11(2), 15, 16(2), 17(5), 20(6), 21(3), 22, 23(12), 24(9), 25, 30(4), 32, 33(2), 34(4), 38(3), 105(2), 107(10), 108(2), 109(2), 110(2), 111(3), 112(2), 113, 124(2), 125, 126, 127 Failure Model 86 Failure Modes Effects and Criticality Analysis (FMECA) N Failure Rate 2, 10(2), 13(3), 14, 17(2), 19, 20, 23(2), 39, 40(2), 41(7), 42(3), 43, 54, 55, 58, 60(3), 61, 62(2), 64(6), 65(2), 66, 67(5), 68, 70(5), 72, 74(6), 77(2), 78(6), 79(2), 83(8), 84, 86, 89(3), 91, 92, 93, 98(2), 100(5), 107, 108(3), 111, 131, 133, 135, 136(3), 138, 139, 141, 143, 144(5), 145(2), 146, 149 Failure Tolerance N Fault Tree 9(7), 11, 16(2), 20, 24, 25(3), 27, 28(5), 29, 30(6), 31, 32(6), 33(3), 34, 35, 39(8), 50, 54(3), 57(2), 59(2) 87(17), 88(10), 92(2), 101, 102, 103, 105, 127(2), 131(9), 132, 133(2), 134, 140(2), 141, 147 Life (lifetime, B10 life, L10 life, life cycle) 12(2), 13, 17, 19, 38, 41(2), 65, 66, 67(2), 68(4), 69, 73, 74, 80, 81, 83, 98, 100, 101, 102, 111 Mean Time 10, 11(3), 13(2), 14, 15(3), 64, 148, 150, 152, 153 Mean Time Between Failures (MTBF) 2, 13, 15, 64, 68 Mean Time to Failure (MTTF) 2, 13, 15, 59(5), 68 Mean Time to Repair (MTTR) 2, 10, 11(3), 14, 15, 54, 55(3), 59(3), 64(5), 148(2), 150(2), 152, 153 Probability 8, 10, 13(2), 14(6), 15, 17, 18(2), 19, 23(2), 25, 28(2) 30,

82 Table 13 - Key Words and Phrases Key Word Page Comments 34(3), 39(2), 40(4), 41(3), 42(5), 43, 44, 45(4), 46(4), 48, 49, 50(3), 51, 53, 54(3), 55(3), 56(2), 57(5), 58(4), 59, 63(3), 65(4), 66(10), 67(3), 70(3), 71(5), 72(3), 81(2), 82, 83(2), 84, 85(3), 86(3), 87(3), 88(7), 89(7), 90(3), 91, 92(6), 93(6), 94(9), 95, 98(2), 101(2) 110, 111(2), 112, 124(2), 128, 131(3), 133(3), 138, 139(2), 140(6), 141(6), 142(3) Probability Risk Assessment N Redundancy 18(2), 20, 25, 34(2), 111, 128(2) Reliability Title Sheet, 1, 2(2), 6(2), 8(5), 9(7), 10(6), 11(3), 12(6), 13, 14, 15(9), 16(7), 17(13), 18(9), 19(15), 20(6), 21, 24, 25, 31(4), 32(3), 33(2), 34, 36, 37, 40(7), 41(3), 42(2), 43(3), 44, 45(2), 50, 54(5), 57(5), 58(2), 59(2), 61(3), 62(2), 63(5), 64(3), 65(3), 67, 68, 70, 71, 72, 73(6), 74(6), 75(9), 76(8), 77, 78(5), 79, 80(2), 83(2), 84(9), 85(3), 86(14), 87, 88(2), 89(2), 91(3), 92(4), 93(3), 94(5), 98(4), 100(3), 101(10), 102(12), 103(6), 104(7), 105(4), 107, 124(2), 127, 131(2), 135(2), 136(2), 137, 138, 139(7), 140(3), 141(3), 142, 144 Reliability Centered Maintenance (RCM) N 493 IEEE Recommended Practice for the Design of Reliable Industrial and Commercial Power Systems 1. Document Information Document Reviewed: 493 IEEE Recommended Practice for the Design of Reliable Industrial and Commercial Power Systems Publisher: Institute of Electronics Engineers, Inc. (IEEE)

83 Published Date of Document: Feb. 7, 2007 Initial Date: 1997 Latest Version: IEEE Std 493-2007 2. General Description of Document: This document presents the fundamentals of reliability analysis applied to the planning and design of industrial and commercial electric power distribution systems. Several new reliability concepts [i.e., inherent availability (Ai) and operational availability (Ai)] are introduced. Chapter 2 provides the theoretical background for the reliability analysis used in other chapters. Chapter 2 includes a detailed list of definitions and formulas. Chapter 3 provides a description of how to make quantitative reliability and availability predictions for proposed new and existing configurations of industrial power distribution systems. Numerical examples are presented using various methodologies to quantify the reliability of the single-line diagram of the Gold Book Standard Network. Reliability- cost/reliability-worth methodology is presented. Chapter 7 discusses the susceptibility of automated equipment to voltage sags. Chapter 8 presents a reliability block diagram methodology to conduct a probability/reliability study of a 7 × 24 continuous power facility. Chapter 10 summarizes the reliability data collected from equipment reliability surveys and a data collection program over a period of 35 years or more. 3. Applicability to NCHRP 12-112 3.1 Components or Systems Covered: Power supply, including emergency and standby. 3.2 Reliability-Based Methodology: The specification is reliability based. 3.3 Use in NCHRP 12-112: With regard to electrical systems, this document offered the most potential. It included data tables summarizing 35-years of reliability data for electrical systems. Relative to movable bridges, the data included transformers, motors, circuit breakers, motor starters, generators, disconnect switches, and cable. HVAC component reliability data is also presented, including accumulators, switches, UPS, and valves. Ultimately, our RBM approach steered away from considering “absolute reliability” due to the multitude of environmental and usage variables in movable bridges.

84 4. Key Words and Phrases: See Table 14 Table 14 - Key Words and Phrases Key Word Page Comments Availability TOC ix(5), TOC x(2), TOC xi, 2(2), 3(4), 7(4), 8, 9(2), 10(2), 12(2), 13(9), 14(15), 15(5), 16, 18, 21(3), 22(3), 23(3), 24, 25, 26, 27(7), 28(2), 29, 30(2), 32(2), 33(2), 34, 36, 37, 41(3), 45, 47, 50, 53, 57, 60, 62(2), 63(10), 64(7), 65(2), 67(4), 78(2), 84, 85, 86, 91(2), 92, 94, 101, 105(3), 109, 110, 111, 112, 119(2), 121, 130, 162, 179, 180, 181(2), 182(2), 183(14), 184(3), 185(2), 194(2), 196(7), 197, 198, 213(2), 214(6), 215(2), 221, 222, 223(4), 224, 261(2), 284, 288, 294, 299, 301, 302, 363, 364, 365(4), 366, 367(3), 368(2), 369 Inherent Availability (Ai) 2, 7(2), 8, 9(2), 10, 13(2), 14(6), 38, 39, 40, 43, 44, 45, 47, 48(2), 49, 51, 52, 55, 56, 58, 60, 61, 83(2), 84, 183(2), 194(2), 195(3), 196(4), 197, 215, 225, 365, 366 Operational Availability (Ao) 2, 8, 9(2), 10, 13, 14(2), 196(4), 197(4), 215, 365, 367 Component Failure (Failed Component) 8, 13, 18, 26, 29, 31, 33, 68, 97, 101, 111, 270, 272(3), 273(7), 274(2), 275, 276, 277(2), 279, 294(4) Criticality 78, 116(3), 121, 366 Durability N Duty Cycle 107, 278 Fail Safe 97 Failure Frequency N Failure Intensity N Failure Mode 10, 16(2), 18(2), 237, 35(6), 36(2), 78, 79, 96, 113, 115, 116(3), 178, 182, 283, 285(2), 286(2), 287, 300(3), 366 FMEA 10, 96, 113, 115, 116(3)

85 Table 14 - Key Words and Phrases Key Word Page Comments Failure Modes Effects and Criticality Analysis (FMECA) 78, 116(4), 366 Failure Rate 7(2), 9(2), 10, 13, 15(2), 17, 18(3), 20(6), 21(3), 29, 31, 33(7), 34, 35, 37(2), 38, 39, 40(2), 41, 43, 44, 45(2), 46(3), 47, 48(2), 49(3), 51, 52, 53(3), 55, 56, 57, 58(2), 59, 60(2), 61(2), 63(8), 64(4), 65, 67, 69(2), 70, 72, 76, 77, 79(2), 81, 82, 83(2), 84, 85, 88, 91, 95, 98, 101, 106(3), 107, 111, 114(2), 116, 150, 153, 181, 184(5), 185(4), 195, 200(6), 213, 215(3), 216, 219(2), 220(2), 221(2), 259(5), 260(5), 261(2), 262(3), 263(6), 269(6), 270(4), 271(8), 278(10), 279(3), 280, 281(2), 282(3), 283(2), 284, 285(2), 288, 293(2), 294(6), 297(8), 298(2), 300(4), 366 Failure Tolerance N Fault Tree 23, 113 Life (lifetime, B10 life, L10 life, life cycle) 13, 15, 18(3), 26(2), 27, 67, 71, 103, 107, 111(2), 112(2), 113(2), 119(2), 120, 127(3), 200(2), 263, 279, 365 Mean Time 2, 8(7), 9(4), 10(4), 14(2), 63, 70, 183(2), 366(10) Mean Time Between Failures (MTBF) TOC ix, 8, 9(4), 10, 14(6), 15(5), 16, 18(2), 27, 70, 183(2), 194(2), 195(2), 196, 366(2) Mean Time to Failure (MTTF) 8(2), 10, 20, 21, 366(2) Mean Time to Repair (MTTR) 2(2), 8, 9(3), 10, 14(5), 15(3), 16, 63, 81, 82, 183, 194(2), 195(2), 196, 366(2) Probability Abstract iv, TOC ix (2), 1, 2, 3, 4, 7(2), 8(2), 10, 11, 12(5), 13(2), 16(11), 17, 21(5), 25(4), 29, 70, 71, 89, 93, 96, 101, 102, 104, 111(3), 112, 114(3), 133, 143(2), 144, 151, 152, 171, 180, 194(3), 195(5),

86 Table 14 - Key Words and Phrases Key Word Page Comments 196, 200, 201(3), 202(3), 203, 204(5), 205(3), 206(4), 213, 215, 300, 365(2), 367(2), 368 Probability Risk Assessment N Redundancy 14, 20, 21(3), 22(3), 61, 111, 112, 119(2), 125, 127, 180, 183(2), 184, 187(2), 188(6), 189, 193, 194(2), 195(2), 197(2), 367(2) Reliability i, Abstract iv(10), Intro v(7), vi(5), TOC ix(7), TOC x(3), TOC xi(5), 1(10), 2(10), 3(12), 4(10), 5(5), 7(12), 8(5), 9(2), 10(2), 11, 12(7), 13(5), 15, 16(4), 18(2), 20(10), 21(6), 22(2), 23(3), 24, 25, 27(2), 28(6), 29(23), 30(6), 31(13), 32(6), 33(5), 34(3), 35(4), 36, 37, 40, 41(3), 45, 47, 50, 53, 57, 60, 62(5), 63(12), 64(14), 65(3), 67(5), 72, 73, 76, 77, 78(8), 79(6), 81(3), 82(5), 83(4), 84(5), 85(7), 86(12), 87(9), 88(7), 89(7), 90(7), 91(3), 93(6), 94, 95(6), 96(2), 97(4), 98(3), 99(3), 100(2), 101(2), 102, 103, 104(2), 105(3), 110(3), 111(5), 112(19), 113, 116(2), 117, 118, 119(5), 121(2), 123(2), 124(2), 125(2), 126, 128(3), 129(4), 130(2), 131(2), 134, 144(2), 172, 173, 174(3), 175, 179, 180, 181(2), 182(7), 183(9), 184(7), 185(3), 189(2), 193, 194(5), 195(6), 196(2), 197, 198, 199(7), 201(2), 203, 205, 207, 209(3), 212(2), 213(11), 214(3), 215(7), 216(3), 217, 219, 221(4), 223(4), 224, 225(4), 227, 229, 231, 233, 235, 237, 239, 241, 243, 245, 247, 249, 251, 253, 255, 257, 259(4), 261(5), 263, 265, 267, 269(3),

87 Table 14 - Key Words and Phrases Key Word Page Comments 270, 271, 273, 275, 277, 278(2), 279, 281, 282(2), 283(6), 284(4), 285(3), 287, 288, 289, 291, 293(2), 294(2), 295, 297(5), 299(9), 300(6), 301(11), 302(5), 303, 304, 305(6), 306, 363(13), 364, 366(4), 367(7), 368(12), 369 Reliability Centered Maintenance (RCM) TOC x (2), 10, 110(2), 111(12), 112(10), 113(18), 114(3), 115(5), 116(3), 368 NEN 6787 The Design of Movable Bridges – Safety Dutch Standard 1. Document Information Document Reviewed: NEN 6787 The Design of Movable Bridges – Safety. Dutch Standard, Publisher: Royal Netherlands Standardization Institute (NEN) Published Date of Document: July 2003 (machine translated from Dutch to English) Initial Date: 2001 Latest Version: 2003 2. General Description of Document: This Dutch standard replaces BS 6786: 1998 in part and is specifically designed for the safety of movable bridges. The standard covers only the risks that characterize movable bridges. 3. Applicability to NCHRP 12-112 3.1 Components or Systems Covered: The standard covers movable bridge safety considerations. 3.2 Reliability-Based Methodology: The document does not use RBM. The document presents information on the consequences of various modes of failure on movable bridge safety. 3.3 Use in NCHRP 12-112:

88 This standard focused primarily on “OHSA-type” safety and hazard identifications. There was little application of this standard regarding RBM design. 4. Key Words and Phrases: See Table 15 Table 15 - Key Words and Phrases Key Word Page Comments Availability N Inherent Availability (Ai) N Operational Availability (AO) N Component Failure (Failed Component) N Criticality N Durability 33, 146 Duty Cycle N Fail Safe 22 The term "fail safe" is not used, but the principle is discussed Failure Frequency N Failure Intensity N Failure Mode N FMEA N Failure Model N Failure Modes Effects and Criticality Analysis (FMECA) N Failure Rate N Failure Tolerance N Fault Tree N Life (lifetime, B10 life, L10 life, life cycle) N Mean Time N Mean Time Between Failures (MTBF) N Mean Time to Failure (MTTF) N Mean Time to Repair (MTTR) N Probability N Probability Risk Assessment N Redundancy N Reliability N Reliability Centered Maintenance (RCM) N

89 NFPA T2.12.11-2-2007, Hydraulic Fluid Power Components – Assessment of Reliability Testing 1. Document Information Document Reviewed: NFPA T2.12.11-2-2007, Hydraulic fluid power components - Assessment of reliability by testing Publisher: NFPA Published Date of Document: NFPA Initial Date: Feb. 22, 2007 Latest Version: NA (if different from document reviewed) 2. General Description of Document: This standard establishes testing methods and procedures for determining the reliability of typical hydraulic system components, including the most common major components used in movable bridge applications. Focus is on BX life and Mean Time to Failure with establishment of component specific threshold levels. System reliability is not specifically addressed. The standard notes the following as guidelines for the expected reliability statements resulting from following the established procedures: "The Bi life of (component) has been substantiation-tested to demonstrate a minimum life of at least ti (cycles, hours, distance) at a confidence level of (C), based on a zero failure Weibayes method." "If the test is successful, the reliability can be stated as follows: The Bj life of (component) has been substantiation-tested to demonstrate a minimum life of at least tj (cycles, hours, distance) at a confidence level of (C), based on a zero/one failure WeiBayes method." "Reliability of hydraulic components tested and assessed in accordance with NFPA/T2.12.11-2-2007, Hydraulic fluid power components – Assessment of reliability by testing." Pump and motor testing specifies reliability rating class definitions that could be referenced by AASHTO. Only pumps and motors in closed circuits are currently addressed. Hydraulic valves covered in the standard are direction control valves, pressure control valves and fluid control valves. 3. Applicability to NCHRP 12-112 3.1 Components or Systems Covered: Hydraulic system components – accumulators, cylinders, filters, pumps, motors & valves.

90 3.2 Reliability-Based Methodology: RBM is not explicitly discussed, however, the focus of the standard is on component reliability which is an important element of RBM. 3.3 Use in NCHRP 12-112: This standard established testing methods and procedures for determining the reliability of typical hydraulic system components, including the most common major components used in movable bridge applications. The defined failure thresholds for various components were also helpful. Discussions with major hydraulic system suppliers indicated that, although they performed similar testing, they did not use this standard. Ultimately, our RBM approach steered away from considering “absolute reliability” due to abundant environmental and usage variables in movable bridges. 4. Key Words and Phrases: See Table 16 Table 16 - Key Words and Phrases Key Word Page Comments Availability N Component Failure 3 Criticality N Durability N Duty Cycle 6, 40, 42 Fail Safe N Failure Frequency N Failure Intensity N Failure Mode Introduction, 4, 6, 46(2), 48(2), 49 FMEA Introduction Failure Modes Effects and Criticality Analysis (FMECA) N Failure Rate N Failure Tolerance N Fault Tree N Life (lifetime, B10 life, L10 life) Introduction (3), 3(3), 4, 5(2), 8(5), 10(2), 11(2), 13(4), 16(5), 17(5), 18(4), 19(5), 20(4), 25, 35(3), 40(4), 41(2), 42(2), 47(5) Mean Time N Mean Time Between Failures (MTBF) 4 Mean Time to Failure (MTTF) 3, 4 Mean Time to Repair (MTTR) N Probability 3, 4(2), 5, 18

91 Table 16 - Key Words and Phrases Key Word Page Comments Probability Risk Assessment N Redundancy N Reliability Title, Introduction (9), 1(5), 3(3), 4(5), 5(5), 6(9), 7, 8(4), 9(3), 10(4), 11, 18, 21, 27, 28, 32, 34, 35, 36, 38(3), 39(7), 40(4), 44(3), 46(4)

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There are approximately 1,000 movable highway bridges in the U.S. inventory.

The TRB National Cooperative Highway Research Program's NCHRP Web-Only Document 314: Updating the AASHTO LRFD Movable Highway Bridge Design Specifications allows bridge owners the option of employing site-specific conditions to develop the design wind speed and provides other general updates to previous research from 2000 that reflects changes in design practice and other standards.

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