1、 To recipients of the Construction Handbook for Bridge Temporary Works, First Edition (1995): Instructions Interim revisions have been made to the Construction Handbook for Bridge Temporary Works, First Edition (1995). They have been designed to replace the corresponding pages in the book and are nu
2、mbered accordingly. Underlined copy indicates revisions that were approved in 2007 by the AASHTO Highways Subcommittee on Bridges and Structures. A listing of newly changed and deleted articles is included with these interim revisions as an addendum to the preface of the book. All revised pages also
3、 display a box in the lower outside corner indicating the interim publication year. Any non-technical changes in page appearance will be indicated by this revision box alone to differentiate such changes from those which have been approved by the AASHTO Highways Subcommittee on Bridges and Structure
4、s. To keep your Specifications correct and up-to-date, please replace the appropriate pages in the book with the pages in this packet. ISBN: 978-1-56051-397-1 Publication Code: CHBTW-1-I1 American Association of State Highway and Transportation Officials 444 North Capitol Street, NW Suite 249 Washin
5、gton, 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 applicable law. 1 CHAPTER 1. INTRODUCTION SCOPE This construction handbook has been developed f
6、or use by contractors and construction engineers involved in bridge construction on Federal-aid highway projects. This document may also be of interest to falsework design engineers, and supplements information found in the Guide Design Specification for Bridge Temporary Works.(1)The content is cons
7、truction-oriented, focusing primarily on standards of material quality and means and methods. This handbook contains chapters on falsework, formwork, and temporary retaining structures. For more in-depth discussion on a particular topic, related literature and references are identified. Chapter Two.
8、 Falsework identifies material standards, the assessment and protection of foundations, construction-related topics, loading considerations, and inspection guidelines. Methods for in situ testing of foundations are identified. General guidelines regarding timber construction, proprietary shoring sys
9、tems, cable bracing, bridge deck falsework, and traffic openings are also discussed. Chapter Three. Formwork identifies and describes the various components and formwork types commonly used in bridge construction. Information on load considerations and design nomographs are provided. General guideli
10、nes relating to formwork construction and form maintenance are also discussed. Chapter Four. Temporary Retaining Structures focuses primarily on cofferdams and their application to bridge construction. As indicated by the chapter title, however, general topics relating to a wide range of temporary r
11、etaining structures are also addressed. Specific topics include classification of construction types, relative costs, sealing and buoyancy control, seepage control, and protection. The construction of timber sheet pile cofferdams, soldier pile and wood lagging cofferdams, and steel sheet pile coffer
12、dams is reviewed. Methods of internal bracing and soil and rock anchorage are also discussed. Section properties of standard dressed and rough lumber, bridge deck falsework design examples, recommended thicknesses for wood lagging, and steel sheet pile data are included as appendixes. Definitions an
13、d related publications are identified below. DEFINITIONS For the purpose of this manual, the following definitions apply. These definitions are not intended to be exclusive, but are generally consistent with the common usage of these terms. Falsework Temporary construction work used to support the p
14、ermanent structure until it becomes self-supporting. Falsework would include steel or timber beams, girders, columns piles and foundations, and any proprietary equipment, including modular shoring frames, post shores and adjustable horizontal shoring. Shoring A component of falsework such as horizon
15、tal, vertical, or inclined support members. For the purpose of this document, this term is used interchangeably with falsework. Formwork A temporary structure or mold used to retain the plastic or fluid concrete in its designated shape until it hardens. Formwork must have enough strength to resist t
16、he fluid pressure exerted by plastic concrete and any additional fluid pressure effects generated by vibration. 2008 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.2 Interim 2008 Cofferdam A temporary watert
17、ight enclosure that allows construction of the permanent structure under dry conditions. RELATED PUBLICATIONS California Falsework Manual, California Department of Transportation, Sacramento, CA. Certification Program for Bridge Temporary Works (FHWA-RD-93-033), Federal Highway Administration, Washi
18、ngton, DC. Formwork for Concrete (SP-4), Seventh Edition, American Concrete Institute, Detroit, MI. Foundation Construction, A. Brinton Carson, McGraw-Hill, New York, NY. Guide Design Specifications for Bridge Temporary Works (FHWA-RD-93-032), Federal Highway Administration, Washington, DC. See also
19、 AASHTO GSBTW-1 (1995) and GSBTW-1-I1 (2008). Guide Standard Specification for Bridge Temporary Works (FHWA-93-031), Federal Highway Administration, Washington, DC. Handbook of Temporary Structures in Construction, R.T. Ratay, Ed., Second Edition, McGraw-Hill Book Company, New York. Lateral Support
20、Systems and Underpinning, Vols. I, II, III (FHWA-RD-75-128, 129, 130), Federal Highway Administration, Washington, DC. Soil Mechanics, Foundations, and Earth Structures (NAVFAC DM-7), Department of the Navy, Alexandria, VA. Standard Specifications for Highway Bridges, 17th Edition (HB-17), American
21、Association of State Highway and Transportation Officials, Washington, DC. Synthesis of Falsework, Formwork, and Scaffolding for Highway Bridge Structures (FHWA-RD-91-062), Federal Highway Administration, Washington, DC. Temporary Works, J.R. Illingworth, Thomas Telford, London, England. 2008 by the
22、 American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.3 Interim2008 CHAPTER 2. FALSEWORK MATERIALS AND MANUFACTURED COMPONENTS Structural Steel Quality of Steel Steel grades greater than ASTM A 36/A 36M are generally not
23、 recommended for falsework construction unless certified or test samples are taken. The Guide Design Specification for Bridge Temporary Works permits the use of higher working stresses for other grades of steel, provided the grade of steel can be identified. Identification is the contractors respons
24、ibility. If steel properties are unknown and test samples are not taken, steel can generally be assumed to be ASTM A 36/A 36M. For reference, some of the more common steel designations predating ASTM A 36/A 36M are provided in table 1. Table 1. Early ASTM steel specifications.(2)ASTM requirement Dat
25、e Specification Remark Tensile strength, lbf/in2Minimum yield point, lbf/in21924-1931 ASTM A 7 (withdrawn 1967) Structural steel 55,000 to 65,000 T.S. or not less than 30,000 Rivet steel 46,000 to 56,000 T.S. or not less than 25,000 ASTM A 9 (withdrawn 1940) Structural steel 55,000 to 65,000 T.S. or
26、 not less than 30,000 Rivet steel 46,000 to 56,000 T.S. or not less than 25,000 1939-1948 ASTM A 7-A 9 Structural steel 60,000 to 72,000 T.S. or not less than 33,000 1939-1949 ASTM A 141-39 (withdrawn 1967) Rivet steel 52,000 to 62,000 T.S. or not less than 28,000 Conversion: 1,000 lbf/in2Dimensiona
27、l Tolerances Rolling structural shapes and plates involves such factors as roll wear, subsequent roll dressing, temperature variations, etc., which cause the finished product to vary from published profiles. Mill dimensional tolerances are identified in AASHTO M 160M/M 160 (ASTM A 6/A 6M), Standard
28、Specification for General Requirements for Rolled Steel Plates, Shapes, Sheet Piling, and Bars for Structural Use.(3)This information is provided in tables 2 and 3 for general reference. Conditioning of Salvaged Steel AASHTO M 160M/M 160 (ASTM A 6/A 6M) also provides guidelines for the condition of
29、plates, structural shapes, and steel sheet piling, as follows: Plate Conditioning Plates may be conditioned by the manufacturer or processor for the removal of imperfections or depressions on the top and bottom surfaces by grinding, provided the area ground is well faired without abrupt changes in c
30、ontour and the grinding does not reduce the thickness of the plate by: (1) more than 7 percent under the normal thickness for plates ordered to weight per square ft, but in no case more than in (3.2 mm); or (2) below the permissible minimum thickness for plates ordered to thickness in inches or mill
31、imeters. 2008 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.4 Table 2. Permissible variations in cross section for W and HP shapes.(3)A, depth, in B, flange width, in Section nominal size, in Over theoretic
32、al Under theoretical Over theoretical Under theoretical T + T, flanges, out of square, max., in Ea, web off center, max., in C, max., depth at any cross section over theoretical depth, in To 12, incl. 1/8 1/8 1/4 3/16 1/4 3/16 1/4 Over 12 1/8 1/8 1/4 3/16 5/16 3/16 1/4 Notes: (a) Variation of 5/16-i
33、n max. for sections over 426 lb/ft. (b) Conversion: 1 in = 25.4 mm; 1 lb/ft = 1.49 kg/m. Table 3. Permissible variations in camber and sweep.(3)Permissible variation, in Sizes Length Camber Sweep Sizes with flange width equal to or greater than 6 in All 1/8 in x (total length, ft) 10 Sizes with flan
34、ge width less than 6 in All 1/8 in x (total length, ft) 10 1/8 in x (total length, ft) 5 4 1/8 in x (total length, ft) with 3/8 in max. 10 Certain sections with a flange width approx. equal to depth and specified on order as columnsaOver 45 ft 3/8 in + 1/8 in x (total length, ft - 45) 10 Notes: (a)
35、Applies only to: W 8 x 31 and heavier, W 10 x 49 and heavier, W 12 x 65 and heavier, W 14 x 90 and heavier. If other sections are specified on the order as columns, the tolerance will be subject to negotiation with the manufacturer. (b) Conversion: 1 in = 25.4 mm; 1 ft = 0.305 m. 2008 by the America
36、n Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.5 Interim2008 Imperfections on the top and bottom surfaces of plates may be removed by chipping, grinding, or arc-air gouging and then by depositing weld metal subject to the
37、 following limiting conditions: The chipped, ground, or gouged area shall not exceed 2 percent of the area of the surface being conditioned. After removal of any imperfections in preparation for welding, the thickness of the plate at any location must not be reduced by more than 30 percent of the no
38、minal thickness of the plate. (AASHTO M 160M/M 160 (ASTM A 6/A 6M) restricts the reduction in thickness to a 20 percent maximum.) The edges of plates may be conditioned by the manufacturer or processor to remove injurious imperfections by grinding, chipping, or arc-air gouging and welding. Prior to
39、welding, the depth of depression, measured from the plate edge inward, shall be limited to the thickness of the plate, with a maximum depth of 1 in (25.4 mm). Structural Shapes and Steel Sheet Piling Conditioning These products may be conditioned by the manufacturer for the removal of injurious impe
40、rfections or surface depressions by grinding, or chipping and grinding, provided the area ground is well faired without abrupt changes in contour and the depression does not extend below the rolled surface by more than: (1) 1/32 in (0.8 mm) for material less than 3/8 in (9.5 mm) in thickness; (2) 1/
41、16 in (1.6 mm) for material 3/8 to 2 in (9.5 to 50.8 mm) inclusive in thickness; or (3) 1/8 in (3.2 mm) for material over 2 in (50.8 mm) in thickness. Imperfections that are greater in depth than the limits previously listed may be removed and then weld metal deposited subject to the following limit
42、ing conditions: The total area of the chipped or ground surface of any piece prior to welding shall not exceed 2 percent of the total surface area of that piece. The reduction in thickness of material resulting from removal of imperfections prior to welding shall not exceed 30 percent of the nominal
43、 thickness at the location of the imperfection, nor shall the depth of depression prior to welding exceed 1 in (32 mm) in any case except as follows: The toes of angles, beams, channels, and zees and the stems and toes of tees may be conditioned by grinding, chipping, or arc-air gouging and welding.
44、 Prior to welding, the depth of depression, measured from the toe inward, shall be limited to the thickness of the material at the base of the depression, with a maximum depth limit of 2 percent of the total surface area. Welding Most of the ASTM-specification construction steels can be welded witho
45、ut special precautions or procedures. The weld electrode should have properties matching those of the base metal. When properties are comparable, the deposited weld metal is referred to as “matching” weld metal. See AWS D1.1/D1.1M(4)for requirements. Table 4 provides matching weld metal for many of
46、the common ASTM-designated structural steels. In general, welding of unidentified structural steel is not recommended unless weldability is determined. Most of the readily available structural steels are suitable for welding. Welding procedures can be based on specified steel chemistry because most
47、mill lots are usually below the maximum specified limits. Table 5 shows the ideal chemistry for carbon steels. 2008 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.6 Interim 2008 Table 4. Matching filler meta
48、l requirements.(4)Welding Processa,bGroup Base metal steel specificationcSubmerged metal arc welding (SMAW) Submerged arc welding (SAW) Gas metal arc welding (GMAW) Flux cored arc welding (FCAW) I ASTM A 36, A 53 Grade B, A 500, A 501, A 529, A 570 Grades 40, 45, and 50 A 709 Grade 36 AWS A5.1 or A5
49、.5 E60XX or E70XX AWS A5.17 or A5.23 F6X or F7X-EXXX AWS A5.18 ER70S-X AWS A5.20 E5XT-X and E7XT-X (except -2, -3, -10, -GS) II ASTM A 242,dA 572 Grades 42 and 50 A 588 A 709 Grades 50 and 50W AWS A5.1 OR A5.5 E70XXeAWS A5.17 or A5.23 F7X-EXXX AWS A5.18 ER70S-X AWS A5.20 E7XT-X (except -2, -3, -10, -GS) III ASTM A 572, Grades 60 and 65 AWS A5.5 E80XXeAWS A5.23 F8X-EXXXfAWS A5.28 ER80SfAWS A5.29 E8XTfIV ASTM A 514 (over 2 in thick), A 709 Grades 100 and 100W
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