1、 AASHTO TITLE CHBTW 95 = 0639804 0033532 OLA AASHTO TITLE CHBTW 95 Ob39804 0033533 T54 I American Association of State Highway and Transportation Officials Executive Committtee 1994-1995 Voting Members Officers: President: Wayne Shackelford, Georgia Vice President: Bill Burnett, Texas Secretary/Trea
2、surer: Clyde E. Pyers, Maryland Regional Representatives: Region I Patrick Garahan, Vermont Region II Ben Watts, Florida Region III Darre1 Rensink, Iowa Region IV Larry Bonine, Arizona Non-Voting Members Executive Director: Francis B. Francois, Washington, D.C. 11 AASHTO TITLE CHBTW 75 Ob37804 00315
3、34 770 AASHTO Highway Subcommittee on Bridges and Structures 1995 JAMES E. SIEBELS, COLORADO, Chairman G. CHARLES LEWIS, GEORGIA, Vice Chairman STANLEY GORDON, FEDERAL HIGHWAY ADMINISTRATION, Secretary ALABAMA, William F. Conway ALASKA, Steve Bradford, Ray Shumway ARIZONA, William R. Bruesch, F. Dan
4、iel Davis ARKANSAS, Dale F. Loe CALIFORNIA, James E. Roberts COLORADO, A.J. Siccardi CONNECTICUT, Gordon Barton DELAWARE, Chao H. Hu D.C., Gary A. Burch, Charles F. Williams, Jacob Patnaik FLORIDA, Jerry Potter GEORGIA, Paul Liles HAWAII, Donald C. Ornellas IDAHO, L. Scott Stokes ILLINOIS, Ralph E.
5、Anderson INDIANA, John J. White IOWA, William A. Lundquist KANSAS, Kenneth F. Hurst KENTUCKY, Richard Sutherland LOUISIANA, Wayne Aymond MAINE, Larry L. Roberts, James E. Tuley MARYLAND, Earle S. Freedman MASSACHUSETTS, Joseph P. Gill MICHIGAN, Sudhakar Kulkarni MINNESOTA, Donald J. Flemming MISSISS
6、IPPI, Wilbur F. Massey MISSOURI, Allen F. Laffoon MONTANA, William S. Fullerton NEBRASKA, Lyman D. Freemon NEVADA, Floyd I. Marcucci NEW HAMPSHIRE, James A. Moore NEW JERSEY, Robert Pege NEW MEXICO, Martin A. Garnick NEW YORK, Michael J. Cuddy, Amn Shirole NORTH CAROLINA, John L. Smith NORTH DAKOTA,
7、 Steven J. Miller OHIO, B. David Hanhilammi OKLAHOMA, Veldo M. Goins OREGON, Terry J. Shike PENNSYLVANIA, Mahendra G. Pate1 PUERTO RICO, Jose L. Melendez, Hector Camacho RHODE ISLAND, Kazem Farhournand SOUTH CAROLINA, Rocque L. Kneece SOUTH DAKOTA, John C. Cole TENNESSEE, Ed Wasserman TEXAS, Charles
8、 C. Terry U.S. DOT, Stanley Gordon (FHWA), Nick E. Mpars UTAH, David L. Christensen VERMONT, Warren B. Tripp VIRGINIA, Malcolm T. Kerley WASHINGTON, M. Myint Lwin WEST VIRGINIA, James Sothen WISCONSIN, Stanley W. Woods WYOMING, David H. Pope ALBERTA, Dilip K. Dasmohapatra MANITOBA, W. Saltzberg NORT
9、HERN MARIANA ISLANDS, NEW BRUNSWICK, G.A. Rushton NEWFOUNDLAND, Peter Lester NORTHWEST TERRITORIES, Jivko Jivkov NOVA SCOTIA, C.Y.S. Nguan ONTARIO, Ranjit S. Reel SASKATCHEWAN, Lome J. Hamblin ENGLAND, Philip J. Andrews MASS. METRO. DIST. COMM., David Lenhardt N.J. TURNPIKE AUTHORITY, Wallace R. Gra
10、nt PORT AUTHORITY OF NY Robert G. Lukas, Ground Engineering Consultants, Inc.; Alan D. Fisher, Cianbro Corporation: Mark K. Kaler, Dayton-Superior Corporation: Harry B. Lancelot, Richmond Screw Anchor Company; Donald F. Meinheit and Raymond H.R. Tide. iv AASHTO TITLE CHBTW 95 Ob39804 003L53b 7b3 Cha
11、pter TABLE OF CONTENTS Page 1 . INTRODUCTION . . 1 SCOPE 1 DEFINITIONS 1 RELATED PUBLICATIONS 2 2 . FALSEWORK . . 3 MATERIALS AND MANUFACTURED COMPONENTS 3 Structural Steel 3 Timber . 7 Manufactured Components 10 FOUNDATIONS . 12 Shallow Foundations . 12 Protection of the Foundation Area . 14 CONSTR
12、UCTION 19 General . 19 TimberConstruction . 19 Vertical Shoring Systems . 21 Cable Bracing 24 Bridge Deck Falsework . 25 Loads During Falsework Erection . 30 Concrete Placement . 30 Load Redistribution 30 DeepFoundations . 13 Traffic Openings 27 LOADING 30 OtherConditions 32 INSPECTION . 32 Vertical
13、Take-up . 32 General . 32 Inspection During Concrete Placement . 33 Inspection After Concrete Placement 33 3 . FORMWORK . 35 INTRODUCTION . 35 FORM COMPONENTS 35 Sheathing . 36 Structural Supports 40 Form Accessories . 43 LOADS . 47 FORMWORKTYPES . 49 Job-Built Formwork 50 Modular Formwork 50 Stay-i
14、n-Place Formwork . 51 Gang Forms 51 Plate Girder Forms 53 FORM MAINTENANCE 56 CONSTRUCTION 54 V Chapter AASHTO TITLE CHBTW 95 W 0639804 0033537 LTT TABLE OF CONTENTS (Continued) Page 4 . TEMPORARY RETAINING STRUCTURES 59 CLASSIFICATIONS 59 INTRODUCTION . 59 Woodsheeting . 62 SoldierPiles . 62 Steel
15、Sheet Piles 66 Tangent Piles . 67 SELECTION OF COFFERDAM SCHEME 68 RELATIVECOSTS . 70 SELECTION OF SUPPORT METHOD . 70 SEALING AND BUOYANCY CONTROL . 71 SEEPAGE CONTROL 72 PROTECTION 75 CONSTRUCTION 76 . Timber Sheet Pile Cofferdam . 76 Soldier PileAiVood Lagging Cofferdam 77 Steel Sheet Pile Coffer
16、dam 78 Soiland Rock Anchors . 80 Internal Bracing 83 . APPENDIX A . SECTION PROPERTIES OF STANDARD DRESSED (S4S) AND ROUGH SAWN LUMBER 89 APPENDIX B . FALSEWORK AND FORMWORK DESIGN EXAMPLES 91 APPENDIX C . RECOMMENDED THICKNESSES OF WOOD LAGGING 113 APPENDIX D . STEEL SHEET PILE DATA 115 REFERENCES
17、. 121 vi AASHTO TITLE CHETW 95 W Ob39804 0031538 536 Figure No . LIST OF FIGURES Page 1 . 2 . Acceptable and unacceptable weld profiles 7 Shapes in which knots appear in various structurai members and methods of measuremen t. 9 3 . Determination of combined slope of grain . 9 4 . Frame and braced to
18、wer buckling modes 11 5 . 6 . Adjustable horizontal shoring beams spanning between bridge piers and temporary timber bents 11 Adjustable overhang bracket for precast concrete stringer . 12 7 . Analysis of plate bearing tests 15 8 . Analysis of pile loading tests 16 9 . Washout under sill support 17
19、10 . Sole plate and bracing details for falsework supported on a sloped surface . 17 11 . Timber cross-bracing between longitudinal stringers 20 12 . Cantilevered ledger beam at temporary pile bent . 20 13 . Examples of plan bracing of modular frames . 22 14 . 15 . 16 . Bracing detail for screw leg
20、supporting a sloped soffit . 23 Typical installation of wire rope clip 25 Bridgedeck falsework . 26 17 . Traffcopenings . 28 18 . Deformation of spans subject to post-tensioning . 31 19 . Formworkcomponents . 35 20 . Plywood sheathing for horizontal formwork 36 21 . Form ties 45 22 . Coil tiesystem
21、. 23 . Exterior and interior formwork hangers . 47 24 . 25 . Distribution of concrete pressure with form height 48 Lateral pressure of concrete on formwork 49 vii AASHTO TITLE CHBTW 95 m Ob39804 0033539 472 m LIST OF FIGURES (Continued) Figure No . Page 26 . Job-buiit formwork . 50 27 . Assembled ga
22、ng form . . 52 Gang form for wali construction 52 28 . 29 . 30 . Plate girder form spanning between two supports 53 Plate girder forms used to fom a bridge pier . 54 31 . Vibration of concrete 55 32 . Installation of wedges . 55 33 . Coilboltassembly 56 34 . Typicalcofferdams . 60 35 . Internally br
23、aced cofferdam systems . 60 36 . Self-supporting and externally anchored cofferdam systems . 61 37 . Types of timber sheet piling . 63 38 . Louver effect for woad lagging . 64 39 . Steel soldier piles 64 40 . 41 . Concrete in-fill between soldier piles . 65 Wood lagging to front flange 65 42 . Typic
24、al steel sheet-piling sections . 66 43 . 44 . Typical pile arrangements . 67 Peneiration of sheeting required to prevent piping in isotropic sand 73 45 . Penetration of sheeting required to prevent piping in stratified sand 74 46 . Wood sheeting systems 76 47 . Soldier pile retained with soil anchor
25、s 78 48 . 49 . 50 . 51 . Sheet pile riving procedure . 79 Sheet pile installation 84 Typical framing arrangements 86 Typical connection for inclined brace and horizontal wale 87 viii AASHTO TITLE CHBTW 75 = Ob37804 003L540 194 LIST OF FIGURES (Continued) Figure No . Page 52 . 53 . Typical wale and a
26、nchor rod details 88 Slab falsework with overhang bracket 92 54 . Load-deflection curve for steel overhang bracket 98 55 . Needle beam for slab overhang 101 56 . Pier cap on friction collar 105 57 . 58 . 59 . Normal interlock swing is at least 10“ on arch web and straight web shapes . 116 Steel shee
27、t piling interlocks in the normal position 117 Steel sheet piling interlocks in the reverse position (not recommended) 117 AASHTO TITLE CHBTW 95 Ob39404 003l154L O20 LIST OF TABLES Table No . Page 1 . Early ASTM steel specifications . 3 2 . Permissible variations in cross section for W and HP shapes
28、 . 4 3 . Permissible variations in camber and sweep . 4 4 . Matching filler metal requirements 6 5 . Referred analysis of carbon steel for good weldability 6 6 . Fahework depth and span relationship 29 7 . Grade-use guide for Plyform sheathing 37 8 . Formulas for stress and deflection calculations f
29、or plywood . 38 9 . Section properties for Plyform Class I and Class II. and Structural I Plyform . 39 10 . Design stresses for Plyform . 39 11 . Formulas for safe support spacings of joists and ledgers 41 12 . Beam formulas 42 13 . Typical equipment for construction of tiebacks 81 14 . Section prop
30、erties of standard dressed (S4S) lumber 89 15 . Section properties of rough sawn lumber 90 16 . Recommended thickness of wood lagging for various soil types . 113 17 . Standard sheet piling (cuca 1972) 118 18 . H-pileproperties 119 X AASHTO AC1 AISC AIS1 AITC ANSI APA ASCE ASTM AWS BOCA FHWA NAVFAC
31、NDS NFPA OSHA UBC in ft Ibf m N kg AASHTO TITLE CHBTW 95 W Ob39804 0031542 Tb7 D ABBREVIATIONS American Association of State Highway and Transportation Officials American Concrete Institute American Institute of Steel Construction American Iron and Steel Institute American Institute of Timber Constr
32、uction American National Standards Institute American Plywood Association American Society of Civil Engineers American Society for Testing and Materials American Welding Society Building Officials or (2) below the permissible minimum thickness for plates ordered to thickness in inches or millimeters
33、. 3 AASHTO TITLE CHBTW 95 m Ob39804 0033547 549 m Section nominal size, in To 12, incl. over 12 T T A, depth, in B, flange width, in T + T, E, C, ma, depth at flanges, out web off any cms scction over Under over Under of square, center, over theordical theoretical theoretical theoretical theoretical
34、 max., in max., in depth, in 1 I8 1 I8 114 3/16 114 3/16 114 118 1/8 1 I4 3/16 5/16 3/16 114 T Certain sections with a flange width approx. equal to depth and specified on order as COlUmIIs 4 1/8 in x (total length ft) wib 3/8 in max. 10 over 45 ft 3/8 in + 1/8 in x - - (total length, ft - 45) - 10
35、W SHAPES I HOIi20“lll rui1.n CHANNELS ANGLES Table 3. Permissible variations in camber and Sizes Permissible variation, in Length Camber I sweep Sizes with flange width quai to or greater than 6 in All (total length, ft) 10 1/8 in x Sizes with flange width less than 6 in All (total length, ft) 1 1/8
36、 in x (total length, ft) 1/8 in x 10 5 4 AASHTO TITLE CHBTW 95 Ob39804 0033548 485 Imperfections on the top and bottom surfaces of plates may be removed by chipping, grinding, or arc (2) 1/16 in (1.6 mm), for material 318 to 2 in (9.5 to 50.8 mm) inclusive in thickness; or (3) 118 in (3.2 mm) for ma
37、terial 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 foliowing limiting conditions: The total area of the chipped or ground surface of any piece prior to welding shall not exceed
38、 The reduction in thickness of the material resulting from removal of imperfections prior to 2 percent of the total surface area of that piece. O welding shall not exceed 30 percent of the nominal thickness at the location of the imperfection, nor shall the depth of depression prior to welding excee
39、d 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. Pnor to welding, the depth of depression, measured from the toe inward, shall be limited to the thickn
40、ess of the material at the base of the depression, with a maximum depth limit of 2 percent of the total surfa area. Welding - Most of the ASTM-specification construction steels can be welded without special precautions or procedures. The weld electrode should have properties matching those of the ba
41、se metal. When properties are comparable, the deposited weld metal is referred to as “matching” weld metal. Table 4 provides matching weld metal for many of the common ASTM-designated structural steels. In general, welding of unidentified structural steel is not recommended unless weldability is det
42、ermined. Most of the readily available structurai steels are suitable for welding. Welding procedures can be bas 1 ft = 0.305 m. Ergure 5. Adjustable horizontai shoring beams spanning between bridge piers and temporary timber bents. 11 AASHTO TITLE CHBTW 95 Ob39804 003355.5 bL5 Slotled 2x6 To - - Cl
43、ear Cad Rod Based on “A” = 9w” O 25 50 75 1 125 Deflection (in) at outboard End of Bracket Conversion: 1 in = 25.4 mm; 1 lbf = 4.45 N Figure 6. Adjustable overhang bracket for precast concrete stringer.” FOUNDATIONS Foundations for falsework are generally temporary in nature. Depending upon the site
44、 conditions, foundation support is most easily provided by simple spread footings unless pile foundations are required. The objective of this section is to familiarize the field engineer with available methods of onsite testing. Field monitoring should also include all site features likely to influe
45、nce foundation behavior. Shallow Foundations Falsework foundations are designed to limit the stress levels in the soil to provide an adequate factor of safety against bearing capacity failure and to limit settlement. The design soil pressures may be selected on the basis of measured or assumed prope
46、rties of the foundation soils that were determined from a site investigation. The construction engineer should familiarize himself with the site investigation data and assumptions used in the design of the foundations to confm that the site soil and design assumptions are consistent with the conditi
47、ons in the field. In many instances, there wili be no doubt as to the adequacy and uniformity of the soil or rock supporting the falsework to receive the applied loads safely. In cases of variable strata, or where any doubt exists concerning the adequacy of the soil or rock, or the general stability
48、 of the site, additional investigation involving in situ tests, test pits, proof-rolling, and/or load tests should be undertaken to obtain sufficient information to ensure the safety of the foundations of the falsework. In Situ Testing - In situ tests can provide sufficient information for confirmat
49、ion of foundation design. In cohesive soils, a hand penetrometer can be used to estimate the unconfined compressive strength of the deposit. Tests should be made at various locations within the bearing area and compared to the results of the previous site investigation and/or the designers assumed value of unconfined compressive strength. In granular 12 AASHTO TITLE CHBTW 95 0639804 0033556 551 soils, field verification of soil strength and compressibility is more difficult. Simple tests include a dynamic cone penetration test where the num
