1、Guide Specifications for Design ofPEDESTRIAN BRIDGES First Edition 2008FRPyawhgiHetatSfonoitaicossAnaciremAslaiciffOnoitatropsnarTdna 2008 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.American Association
2、of State Highway and Transportation Officials 444 North Capitol Street, NW Suite 249 Washington, DC 20001 202-624-5800 phone/202-624-5806 fax www.transportation.org 2008 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of appl
3、icable law. Cover photo courtesy of the Georgia Department of Transportation. 2008 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.iii EXECUTIVE COMMITTEE 20072008 Voting Members Officers: President: Pete K.
4、Rahn, Missouri Vice President: Allen Biehler, Pennsylvania Secretary-Treasurer: Carlos Braceras, Utah Regional Representatives: REGION I: David Cole, Maine, One-Year Term Kris Kolluri, New Jersey, Two-Year Term REGION II: Stephanie Kopelousos, Florida, One-Year Term Butch Brown, Mississippi, Two-Yea
5、r Term REGION III: Debra Miller, Kansas, One-Year Term Kirk Steudle, Michigan, Two-Year Term REGION IV: Gary Ridley, Oklahoma, One-Year Term Rhonda Faught, New Mexico, Two-Year Term Nonvoting Members Immediate Past President: Victor M. Mendez, Arizona AASHTO Executive Director: John Horsley, Washing
6、ton, DC 2008 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.iv HIGHWAY SUBCOMMITTEE ON BRIDGES AND STRUCTURES 2007 MALCOLM T. KERLEY, Chair JAMES A. MOORE, Vice Chair M. MYINT LWIN, Federal Highway Administr
7、ation, Secretary FIRAS I. SHEIKH IBRAHIM, Federal Highway Administration, Assistant Secretary ALABAMA, William F. Conway, John F. Black, George H. Connor ALASKA, Richard A. Pratt ARIZONA, Jean A. Nehme ARKANSAS, Phil Brand CALIFORNIA, Kevin Thompson, Susan Hida, Barton Newton COLORADO, Mark A. Leona
8、rd, Michael G. Salamon CONNECTICUT, Gary J. Abramowicz, Julie F. Georges DELAWARE, Jiten K. Soneji, Barry A. Benton DISTRICT OF COLUMBIA, L. Donald Cooney FLORIDA, Alexander Collins, Marcus Ansley, Andre Pavlov GEORGIA, Paul V. Liles, Jr., Brian Summers HAWAII, Paul T. Santo IDAHO, Matthew M. Farrar
9、 ILLINOIS, Ralph E. Anderson, Thomas J. Domagalski INDIANA, Anne M. Rearick IOWA, Norman L. McDonald KANSAS, Kenneth F. Hurst, James J. Brennan, Loren R. Risch KENTUCKY, Allen Frank LOUISIANA, Hossein Ghara, Arthur DAndrea, Paul Fossier MAINE, James E. Tukey, Jeffrey S. Folsom MARYLAND, Earle S. Fre
10、edman, Robert J. Healy MASSACHUSETTS, Alexander K. Bardow MICHIGAN, Steven P. Beck, David Juntunen MINNESOTA, Daniel L. Dorgan, Kevin Western MISSISSIPPI, Mitchell K. Carr, B. Keith Carr MISSOURI, Dennis Heckman, Paul Kelly, Paul Porter MONTANA, Kent M. Barnes NEBRASKA, Lyman D. Freemon, Mark Ahlman
11、, Hussam Fallaha NEVADA, Mark P. Elicegui, Marc Grunert, Todd Stefonowicz NEW HAMPSHIRE, James A. Moore, Mark W. Richardson, David L. Scott NEW JERSEY, Richard W. Dunne NEW MEXICO, Jimmy D. Camp NEW YORK, George A. Christian, Donald F. Dwyer, Arthur P. Yannotti NORTH CAROLINA, Greg R. Perfetti NORTH
12、 DAKOTA, Terrence R. Udland OHIO, Timothy J. Keller, Jawdat Siddiqi OKLAHOMA, Robert J. Rusch, Gregory D. Allen, John A. Schmiedel OREGON, Bruce V. Johnson, Hormoz Seradj PENNSYLVANIA, Thomas P. Macioce, Harold C. Rogers, Jr., Lou Ruzzi PUERTO RICO, Jaime Cabr RHODE ISLAND, David Fish SOUTH CAROLINA
13、, Barry W. Bowers, Jeff Sizemore SOUTH DAKOTA, Kevin Goeden TENNESSEE, Edward P. Wasserman TEXAS, William R. Cox, David P. Hohmann U.S. DOT, M. Myint Lwin, Firas I. Sheikh Ibrahim, Hala Elgaaly UTAH, Richard Miller VERMONT, William Michael Hedges VIRGINIA, Malcolm T. Kerley, Kendal Walus, Prasad L.
14、Nallapaneni, Julius F. J. Volgyi, Jr. WASHINGTON, Jugesh Kapur, Tony M. Allen, Bijan Khaleghi WEST VIRGINIA, Gregory Bailey, James D. Shook WISCONSIN, Scot Becker, Beth A. Cannestra, Finn Hubbard WYOMING, Gregg C. Fredrick, Keith R. Fulton ALBERTA, Tom Loo NEW BRUNSWICK, Doug Noble NOVA SCOTIA, Mark
15、 Pertus ONTARIO, Bala Tharmabala SASKATCHEWAN, Howard Yea GOLDEN GATE BRIDGE, Kary H. Witt N.J. TURNPIKE AUTHORITY, Richard J. Raczynski N.Y. STATE BRIDGE AUTHORITY, William J. Moreau PENN. TURNPIKE COMMISSION, Gary L. Graham SURFACE DEPLOYMENT AND DISTRIBUTION COMMAND TRANSPORTATION ENGINEERING AGE
16、NCY, Robert D. Franz U.S. ARMY CORPS OF ENGINEERSDEPARTMENT OF THE ARMY, Paul C. T. Tan U.S. COAST GUARD, Nick E. Mpras, Jacob Patnaik U.S. DEPARTMENT OF AGRICULTUREFOREST SERVICE, John R. Kattell 2008 by the American Association of State Highway and Transportation Officials.All rights reserved. Dup
17、lication is a violation of applicable law.TABLE OF CONTENTS v SPECIFICATIONS 1INTRODUCTION 1.1GENERAL.1-1 2DESIGN LOADS 2.1LIVE LOADS.2-1 2.1.1Pedestrian Live Load 2-1 2.1.2Vehicle Load.2-1 2.2WIND LOADS .2-1 2.3COMBINATION OF LOADS 2-1 3DESIGN DETAILS 3.1DEFLECTION 3-1 3.2VIBRATIONS 3-1 3.3ALLOWABL
18、E STRESSES3-1 3.3.1Allowable Stress Limitations3-1 3.3.2Fatigue Provisions.3-1 3.4MINIMUM THICKNESS OF FRP.3-1 3.5CONNECTIONS .3-1 3.6HALF-THROUGH TRUSS SPANS3-1 3.6.1Lateral Force.3-1 3.6.2Top Chords .3-2 3.6.3Sustained Snow Loads3-2 COMMENTARY C1INTRODUCTION C1.1GENERAL . C-1 C2DESIGN LOADS C-1 C2
19、.1LIVE LOADS . C-1 C2.1.1Pedestrian Live Load. C-1 C2.1.2Vehicle Load . C-1 C2.2WIND LOADS . C-1 C2.3COMBINATION OF LOADS. C-1 C3DESIGN DETAILS. C-2 C3.1DEFLECTION. C-2 C3.2VIBRATIONS. C-2 C3.3ALLOWABLE STRESSES C-3 C3.3.2Fatigue Provisions. C-3 C3.4MINIMUM THICKNESS OF FRP . C-3 C3.5CONNECTIONS C-3
20、 C3.6HALF-THROUGH TRUSS SPANS C-3 C3.6.1Lateral Force . C-3 C3.6.2Top Chords C-3 C3.6.3Sustained Snow Loads C-3 REFERENCES R-1 2008 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.SECTION 1 INTRODUCTION 1-1 1
21、.1GENERAL These Guide Specifications shall apply to fiber reinforced polymer (FRP) composite bridges intended to carry primarily pedestrian and/or bicycle traffic. Unless amended herein, the existing provisions of the AASHTO Standard Specifications for Highway Bridges, 17th Edition, shall apply when
22、 using these Guide Specifications, in conjunction with the guidelines in the references. (See References.) 2008 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.SECTION 2 DESIGN LOADS 2-1 2.1LIVE LOADS 2.1.1Pe
23、destrian Live Load Main Members: Main supporting members, including girders, trusses, and arches of the bridge walkway area shall be designed for a pedestrian live load of 85 psf (4.07 kPa). The pedestrian live load shall be applied to those areas of the walkway so as to produce maximum stress in th
24、e member being designed. Secondary Members: Bridge decks and supporting floor systems, including secondary stringers, floorbeams, and their connections to main supporting members, shall be designed for a live load of 85 psf (4.07 kPa). 2.1.2Vehicle Load Pedestrian/bicycle bridges should be designed
25、for an occasional single maintenance vehicle load, provided vehicular access is not physically prevented. A specified vehicle configuration determined by the Operating Agency may be used for this design vehicle. If an Agency design vehicle is not specified, the following loads conforming to the AASH
26、TO Standard H-Truck shall be used. In all cases, a single truck positioned to produce the maximum load effect shall be used: Clear deck width from 6 ft to 10 ft: 10,000 lb (44.48 kN) (H-5 Truck) Clear deck width over 10 ft: 20,000 lb (88.96 kN) (H-10 Truck)The maintenance vehicle live load shall not
27、 be placed in combination with the pedestrian live load. A vehicle impact allowance is not required. 2.2WIND LOADS A wind load of the following intensity shall be applied horizontally at right angles to the longitudinal axis of the structure. The wind load shall be applied to the projected vertical
28、area of all superstructure elements, including exposed truss members on the leeward truss. For Trusses and Arches: 75 psf (3.59 kPa) For Girders and Beams: 50 psf (2.39 kPa) For open truss bridges, where wind can readily pass through the trusses, bridges may be designed for a minimum horizontal load
29、 of 35 psf (1.68 kPa) on the full vertical projected area of the bridge, as if enclosed. A wind overturning force shall be applied according to Article 3.15.3 of the Standard Specifications for Highway Bridges. 2.3COMBINATION OF LOADS The load combinations, i.e., allowable stress percentages for ser
30、vice load design and load factors for load factor design as specified in Table 3.22.1A of the Standard Specifications for Highway Bridges, shall be used with the following modifications: Wind on Live Load (WL) shall equal zero. Longitudinal Force (LF) shall equal zero. 2008 by the American Associati
31、on of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.SECTION 3 DESIGN DETAILS 3-1 3.1DEFLECTION Members shall be designed so that the deflection due to the service pedestrian live load does not exceed 1/500of the length of the span. The d
32、eflection of cantilever arms due to the service pedestrian live load shall be limited to 1/500of the cantilever arm. The horizontal deflection due to lateral wind load shall not exceed 1/500of the length of the span. 3.2VIBRATIONS The fundamental frequency of the pedestrian bridge (in the vertical d
33、irection) without live load shall be greater than 5 Hz to avoid any issues associated with the first and second harmonics. If the second harmonic is a concern, a dynamic computer analysis should be performed. The fundamental frequency of the pedestrian bridge (in the horizontal direction) without li
34、ve load shall be greater than 3 Hz to avoid any issues due to side to side motion involving the first and second harmonics. The fundamental frequencies of the pedestrian bridge in the vertical and horizontal directions shall be different to avoid potential adverse effects associated with the combine
35、d effects from the first and second harmonics in these directions. 3.3ALLOWABLE STRESSES 3.3.1Allowable Stress Limitations Allowable stress values shall be limited to 25 percent of ultimate stress values computed in accordance with ASTM D 7290-06. 3.3.2Fatigue Provisions Standard fatigue provisions
36、do not apply to FRP composite pedestrian bridge live load stresses, as heavy pedestrian loads are infrequent and FRP composite pedestrian bridge design is generally governed by deflection criteria. Wind load concerns are also governed by deflection criteria. 3.4MINIMUM THICKNESS OF FRP Minimum thick
37、ness of closed structural tubular members shall be 0.25 in. (6.4 mm). Minimum thickness of open structural members shall be 0.375 in. (9.6 mm). Minimum thickness of plate connections shall be 0.375 in. (9.6 mm). 3.5CONNECTIONS Bolted connections shall be used for all main and secondary members. Conn
38、ections shall be adequately designed for forces and load transfer mechanisms to mitigate possible failure modes. Galvanized or stainless steel bolts approved by the Operating Agency shall be used. Nonstructural members can be bolted or screwed. 3.6HALF-THROUGH TRUSS SPANS 3.6.1Lateral Force The vert
39、ical truss members of the floorbeams and their connections in half-through truss spans shall be proportioned to resist a lateral force applied at the top of the truss verticals that is not less than 0.01/K times the average design compressive force in the two adjacent top chord members where K is th
40、e design effective length factor for the individual top chord 2008 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.3-2 GUIDE SPECIFICATIONS FOR DESIGN OF FRP PEDESTRIAN BRIDGES members supported between the t
41、russ verticals. In no case shall the value for 0.01/K be less than 0.003 when determining the minimum lateral force, regardless of the K-value used to determine the compressive capacity of the top chord. This lateral force shall be applied concurrently with these members primary forces. End posts sh
42、all be designed as a simple cantilever to carry its applied axial load combined with a lateral load of 1.0 percent of the axial load, applied at the upper end. 3.6.2Top Chords The top chord shall be considered as a column with elastic lateral supports at the panel points. The critical buckling force
43、 of the column so determined shall be based on using not less than two times the maximum design group loading in any panel in the top chord.1Maximum design group loading is based on the design loads (not sustained) specified in Section 2Design Loads in these Specifications. 3.6.3Sustained Snow Loads
44、 For sustained snow loads (duration of load a minimum of 3 days) greater than 65 psf (3.11 kPa), the critical buckling force of the column so determined shall be based on using not less than three times the maximum design group loading in any panel in the top chord. This increased factor will accoun
45、t for any adverse viscoelastic behavior (creep buckling) that potentially could occur in the bridge system. 1For a discussion of half-through truss designs, refer to Galambos, T. V., Guide to Stability Design Criteria for Metal Structures, Fourth Edition, 1988, New York: John Wiley and Sons, Inc., p
46、p. 515529. 2008 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.COMMENTARY C-1 C1INTRODUCTION C1.1GENERAL These Guide Specifications are intended to apply to pedestrian and pedestrian/bicycle bridges that are
47、 part of highway facilities and to provide standards that ensure structural safety and durability comparable to highway bridges designed in conformance with the AASHTO Standard Specifications for Highway Bridges, 17th Edition. These Guide Specifications apply to all bridge types but specifically to
48、fiber reinforced polymer (FRP) composite construction materials. The term “primarily pedestrian and/or bicycle traffic” implies that the bridge does not carry a public highway or vehicular roadway. A bridge designed by these Specifications could allow the passage of an occasional maintenance or serv
49、ice vehicle. These Specifications allow the use of the methodologies provided in the AASHTO Standard Specifications for Highway Bridges, 17th Edition, in conjunction with the References. Service Load Design Approach can be used for particular applications where vehicle loading conditions are restricted to an H-5 truck. For a discussion of the Service Load Design Approach for FRP Composite Pedestrian Bridges, see Wallace (1999). C2DESIGN LOADS C2.1LIVE LOADS C2.1.1Pedestrian Live Load The 85 psf (4.07 kPa)
