- 525 - SECTION 708 -- STEEL STRUCTURES
708.01 Description
1.a. This work shall consist of furnishing, fabricating, and erecting all bolted or welded steel structures. They shall be fabricated, constructed, and erected in accordance with the det ails shown in the contract and as required by these Specifications.
b.Construction of the steel supe rstructure for a new steel girder bridge is described by the pay item "St eel Superstructure at Station _____".
c.When the Department widens or repairs a bridge with steel components, the work is described by the pay items "Structural Steel for Superstructure and/or Substructure". These pay items are also found on new bridges when steel components are required to complete the construction. However, when these pay items are used, notes are placed in the contract to describe what steel items are to be cons tructed by the pay item "Structural Steel for Superstructure and/or Substructure".
2.The structural steel fabricat ing plants doing work for the NDOT shall be certified under the AISC Quality Certification Program:
a.Category "SBR" certificatio n is required to fabricate main members of Simple Steel Bridge Structures.
b.Category "CBR" certificatio n is required to fabricate main members of Major Steel Bridges (ot her than rolled beam structures).
c.When a fabricator holds eith er a SBR or CBR certificate, a Certified Welding Inspector must be pres ent during all aspect s of fabrication and painting. The Certified Welding Inspector must follow the specified duties for Quality Control accordin g to AWS DW 1.5 Section 6.0.
d.Category "SBD or SBR" cert ification is required to fabricate secondary members.
e.Sole Plate fabrication for Bearing Devices is allowed without AISC certification.
3.a. All welding and weld qualif ication tests shall conform to the provisions of the current ANSI/AASHTO/AWS D1.5 Bridge Welding Code, referred to as AWS Standard Specifications .
b.The Quality Control personn el must be a Certified Welding Inspector and shall be separate from production. The Quality Control personnel shall be present at all times during fabrication and painting. The Quality Control personnel shall be kn owledgeable of the specification requirements to insure that the fabr ication performance is in conformance with the contract and the current AWS D1.5 Bridge Welding Code book.
4.Field Welding shall require a Wel der Qualification Ce rtification. The certification for the welder performing the work shall be submitted to the Engineer three weeks prior to starting t he welding. The welder shall produce his/her credentials and photo ID at the jobsite.
5.Field welding is prohibited unless specifically shown in the contract.
6.Welder Certification: a. All welders, operators, and tackers shall be competent, trained in the particular arc welding process to be used, experienced in the type of
708.01 Steel Structures
- 526 - welding required, and capable of producing reliable fillet and groove welds in the weld positions for which they are qualified.
b.(1) All welders shall be qualified under AWS Standard Specification criteria.
2.Qualification testing is required. (3) The testing may be done by the Engineer, a private laboratory recognized and accepted by the Engineer, or laboratories of other State Highway Departments. The qualifications of welders, operators, or tackers shall remain in effect indefin itely unless the person is not engaged in the given welding process for more than 6 months or unless there is some specific reason to question the person's ability.
4.A certificate of the welder's qualifications shall be initially submitted to the Engineer. The in itial certificat e shall state:
i.The name of the welder, operator, or tacker. (ii) The name and title of the Engineer that observed the testing. (iii) The arc welding process. (iv) The welding position.
v.The qualification positions. (vi) Whether for groove or fillet weld. (vii) Whether for limited or unlimited plate thickness. (viii) The AWS Electrode and flux or electrode classification. (ix) The date and results of the test and any other pertinent information.
5.Failure to follow described welding procedures while performing the work may be cause for suspending a welder's qualifications in Nebraska.
6.All suspensions may be contested by an appeal to the Engineer.
c.The Contractor shall furnis h a certified statement for each welder, operator, or tacker stating that they have satisfactorily welded with the required processes in the 6-m onth period before the subject work.
d.To arrange Department Qualif ication Testing, the Contractor shall notify the Engineer as to the time and location of the test at least 48 hours in advance of the time the testing will begin so that the Engineer may observe the weld test. e . AWS Standard Specifications weld test procedures shall be used to evaluate the welds made by automatic welding machines. Steel Structures 708.02 - 527 - 708.02 -- Material Requirements
1.Materials shall conform to the requirements in Table 708.01. Table 708.01 Applicable Materials Section Structural Steel ........................................... .1045 Low Strength Bolts, Nuts and Washers ...... .1057 Structural Th readed Fa steners ................... .1057, 1058 Steel Fo rging .............................................. .1048 Cold-Finished Bars and Shafting ................ .1049 Steel Ca stings ............................................ .1050 Gray Iron Castings ...................................... .1051 Malleable Castings ..................................... .1051 Sheet Lead ................................................. .1055 Sheet Al uminum ......................................... .1054 Iron Pi pe ..................................................... .1039 Steel Pipe ................................................... .1040 Welding El ectrodes ..................................... .1047 End Weld ed Studs ...................................... .1046
2.Wherever steel shapes, plates , and miscellaneous steel items are specified, all designations and dimensional requirements shall be understood to be the same as those of the AISC Manual of Steel Construction .
3.Certified Mill Test Reports:
a.The Contractor shall furnish to the Engineer 3 copies of all mill orders or 3 copies of the Certified Mill Test Reports before starting fabrication of material covered by these reports.
b.Before the project is complete, the Certified Mill Test Reports must be provided to the Engineer.
4.The Contractor, through the f abricator, shall furnish to the NDOT Bridge Engineer a cutting list of all material to be used. The list shall include the direction of rolling (only for splice plates, bent plates, flanges, and webs), heat numbers, and fabric ation piece marks.
5.All material shall be stored in such a manner as to prevent rust. Material shall not be stored so as to rest upon the ground or in water, but must be placed on suitable skids or platforms.
6.Threads for all bolts and pins fo r structural steel construction shall conform to the Unified Standard Series UNC - ANSI B1.1, Class 2A for external threads and Class 2B for inte rnal threads, except that pin ends having a diameter of 1.4 inches (35 mm) or more shall be threaded, 1 thread per each 0.16 inch (4 mm) of bolt length.
7.Sheared plates more than 5/8 inch (16 mm) thick which carry calculated stresses shall have the ent ire sheared surface planed, milled, ground, or thermally cut to remove 1/ 4 inch (6 mm) of t he plate along the entire cut.
8.Bolts, nuts, and washers used in the assembly of "weathering" steel shall conform to ASTM A325/A 325M Type 3.
708.02 Steel Structures
- 528 - 9. This Specification covers sw edged anchor bolts, nuts and washers for use on bridge bearing devices:
a.Anchor Bolts
1.Unless specified otherwise in the contract, anchor bolts shall conform to the requirem ents of ASTM A307, Grade A.
2.Coating. The anchor bolts shall be hot-dipped galvanized after fabrication. The galvanizing shal l comply with the requirements of ASTM A153.
3.Threads. Anchor bolts shall be threaded to the length shown on the contract. Threads shall be the Coarse Thread Series as specified in ANSI B1.1 and may be formed by cutting or rolling. The minimum body diameter on products for which no minimum limits are shown in the dimensional tables shall not be less than the minimum pitch diameter of the thread (See ANSI B18.2.1 and ANSI B1.1).
4.Deformations. The depth of the deformation of the swedged anchor bolt shall not be more than 1/8 inch (3 mm) with a radius not less than 1/2 inch (12.5 mm). There shall be no more than one deformation occurring in any plane perpendicular to the shaft of the bolt. There shall be at least one deformation within each 1 inch (25 mm) length of the bolt and the deformations shall be a minimum of 90 degrees out of phase with the adjacent deformation. No cutting is allowed to form deformation. b . N u t s
1.Dimension. Nuts for anchor bolts shall be Heavy Hex nuts as specified in ANSI B18.2.2.
2.Strength. Nuts shall comply with the proof load or Brinell hardness requirements of ASTM A307.
3.Threads. Threads shall be the Coarse Thread series as specified in ANSI B1.1.
4.Coating. The nuts and washers shall be hot-dipped galvanized after fabrication. The galvanizing shall comply with the requirements of ASTM A153.
5.Thread fit. After galvanizing, the thread fit of the bolt-nut combination shall be snug and shall be such that the nuts can be turned on the bolts without the app lication of excessive torque. The Engineer may conduct proof load tests on the bolt-nut combination to check the thread fit.
c.Washers
1.Washers for use with anchor bolts shall be Type A or Type B Regular as specified in ANSI B18.22.1 except that the following tolerances, based on uncoated washers, shall apply:
i.Inside diameter ± 1/16 inch (1.6 mm) (ii) Outside diameter ± 1/18 inch (1.4 mm) (iii) Thickness -0.03, +0.05 inch (-.8 mm, +1.3 mm)
10.Any bolt lots which do not bear the Department inspection tags and markings will not be accepted by the Engineer. Steel Structures 708.03 - 529 - 11. If the fasteners are shipped to the job site directly from the manufacturer, fabricator, or supplier , they must be sampled by State personnel and submitted to the NDOT Materials and Research Division for testing.
12.Prestressed concrete girder structures:
a.All structural steel used in steel diaphragms shall conform to the minimum requirements of ASTM A709/A709M, Grade 36 steel, and shall be galvanized in accordance with ASTM A123.
b.Bolts, nuts, and washers us ed to install and assemble steel diaphragms shall conform to ASTM A325 or ASTM A325M and shall be galvanized in accordance with ASTM A153.
13.Shear connectors shall conform to the requirements of Subsection 708.02 and Section 1046 of the Standard Specifications.
708.03 Construction Methods
1.General Requirements:
a.The Contractor shall assemble and place all structural steel as shown in the contract.
b.All structural steel shall be shaped by methods which will not damage the metal. Metal with sharp kinks or bends shall be rejected.
c.Bent steel shall be shaped using procedures that will not produce fractures or damage. The metal shall not be heated unless approved by the Engineer, in which case the heating shall not be done to a temperature higher than 1150°F (621°C) . After heating, the metal shall be left to cool at ambient air temperatures above 40°F (4°C). Accelerated cooling is not allowed.
d.The work quality and finish shall equal or exceed ANSI, AASHTO, and AWS Standards.
e.Shearing, thermal cutting, and chipping shall be done accurately; and all portions of the work shall be finished neatly.
2.Plans and Working Drawings: a. Plans shall be supplement ed by the Contractor's working drawings provided in accordance with the requirements of Subsection 105.02.
3.Bolt Holes: a. The Contractor shall punch or drill and ream all bolt holes. Material forming parts of a member composed of not more than 5 thicknesses of metal may be punched 1/16 inch (1.5 mm) larger than the nominal diameter of the bolts whenever the thickness of the metal is not greater than 3/4 inch (19 mm) for structur al steel or 5/8 inch (16 mm) for high strength low alloy steel.
b.When there are more than 5 thicknesses of material or when any of the main material is thicker th an 3/4 inch (19 mm) in carbon steel or 5/8 inch (16 mm) in alloy steel, or when required under Paragraph 6. of this Subsection, all the holes shall be subp unched or subdrilled 3/16 inch (5 mm) smaller and, after assembling, reamed 1/ 16 inch (1.5 mm) larger or drilled 1/16 inch (1.5 mm) larger than t he nominal diameter of the bolts.
708.03 Steel Structures
- 530 - 4. Punched Holes: The diameter of the die shall not ex ceed the diameter of the punch by more than 1/16 inch (1.5 mm). If any holes must be enlarged to admit the bolts, they shall be reamed. Holes must be clean cut and without torn or ragged edges. Material with poorly matching holes will be rejected.
5.Accuracy of Hole Group: a. All holes punched full size, subpunched, or subdrilled shall, after assembling (before any reaming is done), allow a cylindrical pin 1/8 inch (3 mm) smaller in diameter th an the nominal size of the punched hole to be entered perpendicular to the face of the member, without drifting, in at least 75% of the contiguous hole s in the same plane. If the requirement is not fulfilled, the badly punched pieces will be rejected. If any hole will not pass a pin 3/16 inch (5 mm) smaller in diameter than the no minal size of the punched hole, this will be cause for rejection.
b.When holes are reamed or dr illed, 85% of the holes in any contiguous group shall, after reaming or drilling, show no offset greater than 1/16 inch (15 mm) between adjacent thicknesses of metal.
c.Having met the foregoing criteria, remaining offsets may be corrected by further reaming to admit bol ts perpendicular to the face of the member.
d.Except where restoration by welding is necessary for structural or other reasons, mislocated holes shall be left open or filled with bolts.
e.Reaming: (1) Reamed or drilled holes shall be cylindrical, perpendicular to the member, and shall comply with Paragraph 3. of this Subsection as to size.
2.Where practical, reamers shall be directed by mechanical means.
3.Burrs on the outside surfaces shall be removed. (4) Reaming and drilling shall be done with twist drills, twist reamers, or sluggers (rotobroach cutters).
5.Connecting parts requiring reamed or drilled holes shall be assembled and securely held while being reamed or drilled and shall be match-marked before disassembling.
f.Tolerances:
1.Holes not more than 1/32 inch (0.75 mm) larger in diameter than the true decimal equivalent of the nominal di ameter that may result from a drill or reamer of the nominal diameter are considered acceptable. The slightly conical hole th at naturally results from punching operations is considered acceptable.
2.The width of slotted holes which are produced by thermal cutting or a combination of drilling or punching and thermal cutting shall generally be not more than 1/32 inch (0.75 mm) greater than the nominal width.
3.The thermal cut surface shall be ground smooth. Steel Structures 708.03 - 531 - 6. Drilling, Subpunching, Reaming, and Shop Assembly:
a.(1) Unless otherwise specified, holes in all field connections and field splices of main members of trusses, arches, continuous beams, girders, or rigid frames shall be drilled full size or subpunched (or subdrilled) and reamed, with all members assembled in the shop.
2.If splices are to be drilled full size, one splice plate from each flange or from each web splice may be predrilled full size and the predrilled plate used as a template for drilling the flange or web and opposite splice plates, provided the resulting holes are equal in quality to holes drilled completely or subdrilled (or subpunched) and reamed through the assembled plates.
3.The assembly, including camber, alignment, and accuracy of holes and milled joints, shall be ap proved by the Engineer before reaming of under size holes or drilling of full size holes is commenced.
4.The connecting parts shall be assembled and held securely while being reamed or drilled and shall be match-marked.
5.No parts shall be interchanged. (See Paragraph 8. of this Subsection.)
b.All holes for field end connections of floor beam and stringers shall be subpunched and reamed to a steel templet or reamed while assembled.
c.The Contractor shall clean metal surfaces before assembling. The parts of a member shall be assembled, well pinned, and firmly drawn together with bolts before reaming is commenced. Assembled pieces shall be taken apart, if necessary, for the removal of burrs and shavings produced by the reaming operation. The member s shall be free from twists, bends, and other deformation.
7.Drifting of Holes: The drifting done during assembling shall be only that amount necessary to bring the parts into position and not sufficient to enlarge the holes or distort the metal. If any hole s must be enlarged to admit the bolts, they shall be reamed.
8.Matchmarking: a. Connecting parts assembled in the shop for the purpose of reaming holes in field connections shall be matchmarked by the Contractor, and a diagram showing such marks shall be furnished to the Engineer.
b.Where steel stamping is used , impressions shall be placed on the thicker tension-joint member in transition joints. Impressions shall not be made on tensile-stressed plate members except at field splices. The maximum allowable depth of the impression shall be 0.01 inch (250 µm). Any metal die stamping shall be done using low-stress dies with rounded edges conforming with the requ irements in Table 708.02.
708.03 Steel Structures
- 532 - Table 708.02 Low Stress Die Edges Character Size inches(millimeter) Minimum Character Face Radius inches(micrometer) 1/8 (3) .007 (180) 3/16 (4.5) .008 (212) ¼ (6) .010 (250)
9.Unfinished Turned or Ribbed Bolt Connections (Not applicable to high-strength bolts):
a.The Contractor shall provid e bolted connections as required by the contract.
b.Unless otherwise specified, approved lock washers shall be used on all bolts.
c.Bolts transmitting shear shall be threaded to such a length that not more than one thread will be within the grip of the metal.
d.The bolts shall be of lengths which will extend entirely through their nuts and washers but not more than 1/4 inch (6 mm) beyond them.
e.All bolts shall have hexagonal heads and hexagonal nuts. The diameter of the bolt holes shall be no t more than 1/16 inch (1.5 mm) greater than the diameter of the bolts used unless otherwise shown.
10.Structural Joints Usi ng High Tensile Steel Fasteners:
a.When shown in the contract, high tensile steel bolts shall be used for the fabrication of structural st eel forming rigid joints in installations where the initial tension in the bolt body is depended upon to produce resistance to shear loads through friction at the faying surfaces.
b.Fastener material requirements, as well as manufacturing, testing, documentation, and shipping re quirements, shall be as set forth in Section 1058.
c.Testing:
1.The rotational capacity te st described in Se ction 1058 will also be performed by the NDOT Materials and Tests Division on each rotational capacity lot before bolt installation at the project site or fabricator's plant.
2.This test will be performed by the Department in addition to the rotational capacity testing certifie d by the manufacturer or distributor.
3.If the fasteners are shipped to the job site directly from the manufacturer, fabricator, or supplie r, the Engineer has the option of performing the rotational capacity test a nd verification testing required in Section 1058 at the job site or fabricator's plant.
4.If, however, the bolts have not been pretested in accordance with AASHTO M164 (ASTM A325) by State personnel, they must be sampled by State personnel and submitted to the NDOT Materials and Tests Division for testing.
5.These requirements apply to shop bolts as well as field bolts. Steel Structures 708.03 - 533 - d. Bolted parts shall fit solidly together when assembled. There shall be no compressible material such as gaskets or insulation within the grip. Holes may be punched, subpunched or reamed, or drilled as required by the applicable specifications and shall be of a diameter not more than 1/16 inch (1.5 mm) in excess of the nominal bolt diameter.
e.Faying Surface Preparation:
1.The faying surfaces shall be free of burrs, pits, and other defects that would prevent solid seating of the parts or would interfere with the development of friction between the parts. The Contractor shall clean surfaces that are to be painted in accordance with Subsection 709.03, Paragraph 1.b.
2.If unpainted "weathering" steel is specified, the faying surfaces shall be cleaned as described in Subsection 709.03, Paragraph 4.
f.Bolts: (1) Heavy hex structural bolts and heavy hex nuts shall be required unless other dimensional requirements are stipulated in the contract.
2.Bolts shall be assembled with a hardened washer under the nut, unless otherwise specified.
3.A hardened steel flat washer shall be used when the abutting surface adjacent to the bolt head or nut does not have a slope of more than 1 to 20 with respect to a plane normal to the bolt axis.
4.Where an outer face of t he bolt part has a slope of more than 1 to 20 with respect to a plane normal to the bolt axis, a smooth, hardened steel beveled washer shall be used to compensate for adjoining surfaces not being parallel.
g.Installation:
1.The sequence of tightening the bolts in a connection shall be such that the stiffest or most rest rained area is tightened first, with work progressing toward the free edges.
2.Sufficient bolts shall be installed and brought to a "snug- tight" condition to ensure that all parts of the connection are in full contact.
3.Snug-tight is defined as the tightness attained when an impact wrench begins to impact or when the full effort of a person using a standard 18 inch (450 mm) spud wrench is applied.
4.Snug-tight is more specifically defined as the tightness necessary to produce approximately 15 % (but no more than 50%) of the minimum bolt tension as shown in Table 708.03 (A or B), column (3).
5.This snug-tight tension may be verified using an approved bolt tension calibrator.
6.All remaining bolts shall be installed and tightened to a snug-tight fit.
7.The Engineer may require bolts previously installed to be rechecked for tightness.
708.03 Steel Structures
- 534 - Table 708.03A Bolt Tension ASTM A325 Bolts Used in Slip-Critical and Direct Tension Connections
U.S. Standards
1.(2) (3) (4) Bolt Size Snug-Tight Tension (kips) * Minimum Bolt Tension (kips) +5% Required Installation Tension (kips) 1/2” 2 12 13 5/8” 3 19 20 3/4” 4 28 29 7/8” 6 39 41 1” 8 51 54 1 1/8” 8 56 59 1 1/4” 11 71 75 1 3/8” 13 85 89 1 1/2” 15 103 108 * Minimum tension values shown in column (3) are equal to 70% of the specified tensile load as sh own in ASTM A325 specifications (tested full size with UNC threads loaded in axial tension), rounded to the nearest kip (kN). Table 708.03B Bolt Tension ASTM A325M Bolts Used in Slip-Critical and Direct Tension Connections SI Standards
1.(2) (3) (4) Bolt Size (mm) Snug-Tight Tension (kN) * Minimum Bolt Tension (kN) +5% Required Installation Tension (kN) 16 14 91 96 20 21 142 149 22 26 176 185 24 31 205 215 27 40 267 280 30 49 326 342 36 71 475 499 * Minimum tension values shown in column (3) are equal to 70% of the specified tensile load as sh own in ASTM A325 specifications (tested full size with UNC (metric coarse) threads located in axial tension), rounded to the nearest kip (kN). Steel Structures 708.03 - 535 - h. Bolt Tension Methods: High strength fasteners must be installed using either the turn- of-nut method.
1.Turn-of-Nut Method: (i) The following requirements for installation of fasteners by this method apply in addition to the specifications in the AASHTO Standard Specifications for Highway Br idges, Division II, Section 11, when high-strength bolts are installed in the field or shop. (ii) Bolts shall be inst alled in accordance with AASHTO
Division II — , Section 11, Arti cle 11.5.6.4.4, for turn-o f-nut tightening, using
required hardened steel washers under the turned element (the turned element being the high strength nut, unless otherwise specified). (iii) If the manufacturer's markings on the nuts are raised, the nuts must be installed so that the markings are not in contact with the hardened washer. (iv) During installation, particular care should be exercised so that the required s nug-tight condition is achieved.
v.After all bolts in the connection have been properly snug-tightened (see Paragraph 10.g. of this Subsection), the nuts shall be match-marked by the Contractor or f abricator using paint, crayon, or other approved means in order to provide the Engineer a reference for determining the relative rotation of the parts during final tightening. (vi) The outer face of the nut must be match-marked to the protruding end of the bolt after the joint has been snug-tightened, but before final tightening.
708.03 Steel Structures
- 536 - Table 708.04 Nut Rotation from Snug-Tight Condition Disposition of Outer Faces of Bolted Parts Bolt Length (as measured from underside of head to extreme end of point) Both faces normal to bolt axis One face normal to bolt axis and other face sloped not more than 1:20 (bevel washer not used) Both faces sloped not more than 1:20 from bolt axis (bevel washers not used) Up to and including 4 diameters 1/3 turn 1/2 turn 2/3 turn Over 4 diameters but not exceeding 8 diameters 1/2 turn 2/3 turn 5/6 turn Over 8 diameters but not exceeding 12 diameters 2/3 turn 5/6 turn 1 turn Table Notes:
1.Nut rotation is relative to bolt, regardless of the element (nut or bolt) being turned. For bolts installed by 1/2 turn and less, the tolerance should be plus or minus 30 degrees. For bolts installed by 2/3 turn and more, the tolerance should be plus or minus 45 degrees.
2.No research work has been performed by the Research Council on Riveted and Bolted Structural Join ts to establish the turn-of-nut procedure when bolt lengths exceed 12 diameters. Therefore, the required rotation must be determined by actual tests in a suitable tension device simulating the actual conditions.
3.Applicable only to connections in which all material within grip of the bolt is steel. (vii) The element not being turned must be held stationary with a wrench or other suitable means to ensure that no rotation of the unturned element occurs. (viii) After being properly match-marked, the bolts shall be tensioned by applying the amount of nut rotation as specified in Table 708.04. (ix) If impact wrenches are used for tightening, they shall be of adequate capacity and sufficiently supplied with air to perform the required tightening of each bolt in approximately 10 seconds.
x.When all bolts in the connection are tight, each bolt should provide a tension at least 5% greater than the minimum tension values shown in Table 708.03 (A or B), column (3). (xi) These minimum installation tension values are shown in column (4) of Table 708.03 (A or B).
i.Inspection: (1) Fasteners of appropriately assigned and tested lot numbers shall be assembled together when installed. Steel Structures 708.03 - 537 - (2) Such fasteners shall be protected from dirt and moisture at the job site (in protective storage from the outside elements) in the original containers. These containers or ke gs will be sealed and tagged by Department personnel before shipment.
3.Only as many fasteners as are anticipated to be installed and tightened during a work shift shall be taken from the pr otected storage. Fasteners not used shall be returned to the protective stor age at the end of the shift.
4.Any fasteners not properly stored or handled are subject to rejection by the Engineer.
5.Fasteners shall not be cleane d of lubricant that is required to be present in the as-delivered condition.
6.The Contractor in the fi eld and the bridge fabricator in his/her shop shall provide a certified, ca librated, dial indicator type manual torque wrench and bolt tension measuring device (a Skidmore-Wilhelm calibrator or other acceptable bolt tension indicating device) when high- strength fasteners are being tightened and the Engineer requires a rotational capacity test as required in Section 1058 and/or to verify the tension requirements of Table 708.03 (A or B) for the complete fastener assembly.
7.Calibration of this equipment will be performed by the Department’s Materials and Research Division. Such devices must be submitted to the Department at least 1 week before their use is anticipated.
8.Recalibration of the to rque wrench and tension measuring device will be required at any time which, in the opinion of the Engineer, the equipment is not functioning properly or is out of calibration.
9.Bolts tightened by the turn-of-nut method may be accepted by the Engineer on the basis of a visual inspection of the match- marks.
10.If there is a disagreement or question as to the tension of the installed bolts, the Engineer sha ll require the following procedure to be used:
i.Five bolts of the same brand, grade, diameter, length, and condition as those under inspection shall be placed individually in the calibration device. The samples sele cted must be repr esentative of the fasteners used in the work and should be from the same manufacturer's lot if at all possible. (ii) When the fasteners to be inspected have been installed in the structure for any signif icant length of time as determined by the Engineer and have been exposed to the elements, the samples should be selected from the fasteners in the work. (iii) A hardened steel washer must be used under the nut's faying surface with a minimum of 3, but not more than 5, exposed threads included in the grip portion of the bolt. (iv) Steel shim plates may have to be used as spacers between the washer and the calibrator in order to provide this spacing requirement.
708.03 Steel Structures
- 538 - (v) Bolts must first be brought to a snug-tight tension as shown in Table 708.03 (A or B). (vi) Match-marks are then applied for the purpose of rotational referencing from snug-tight. (vii) Each of the 5 bolts shall then be tightened in the calibration device, beyond snug-tight, by any convenient means to the minimum tension specified for its size as shown in Table 708.03 (A or B), column (3). (viii) Tightening from the initial snug-tight condition must not produce greater nut rotation t han that allowed in Table 708.05. (ix) The inspecting wrench shall then be applied to each of the 5 tightened bolts and the torque necessary to turn the nut 5 degrees [1 inch (25 mm) in a 12 inch (300 mm) radius] in the tightening direction shall be determined.
x.From a practical standpoint, this is the torque necessary to just start rotation of the nut. Record all 5 torque determinations. (xi) The job inspection torque shall be taken as the average of the 3 remaining values after rejecting the high and low values. (xii) This job inspection torque is to be used in the manner specified as follows:
a.Bolts represented by the sample described in Paragraphs 10.i.(10)(x), and (xi) of this Subsection which have been tightened in the structure shall be in spected by applying the inspecting wrench with the accompanying job inspecting torque to a minimum of 10% of the bolts, but not less than 2 bolts, se lected at random in each connection.
b.If no nut is turned by this application of the job inspection torque, the connection shall be accepted as properly tightened. If any nut is turned by the application of job inspection torque, this torque shall be applied to all bolts in the connection, and all bolts whose nut is turned by the job inspection torque shall be tightened and reinspected; or, alternatively, the fabricator or Contract or may retighten all of the bolts in the connection and then resubmit the conn ection for the specified inspection. Table 708.05 Maximum Nut Rotation from Snug-Tight Bolt Length Rotation 4 diameters or less 1/2 turn Greater than 4 but not exce eding 8 diameters 3/4 turn Greater than 8 diameters but not exceeding 12 1 turn
11.The Engineer will monitor the fastener conditions in order to detect any change in the level of lubrication or accumulation of dirt or other detrimental fastener conditi ons. At any time during the erection process when the Engineer suspects t here may have been a change in the lubrication or fastener conditions, he/she may require the Contractor to run a rotational capacity test as well as veri fication testing as indicated in these Specifications.
12.Bolts tightened in-place, then removed, shall be discarded and not reused. Steel Structures 708.03 - 539 - 11. Bearing Surfaces and Abutting Joints:
a.Bearing surfaces shall conf orm to the ANSI B46.1, Surface Texture in Table 708.06. Table 708.06 Surface Texture Surface Texture Steel slab s ..................................................................... 2000 Heavy plates in cont act with s hoes ................................ 1000 Flame cut surfaces of members carrying calculated stress .............................................................................1000 Flame cut surfaces of members not carrying calculated stress ............................................................2000 Mill ends of compre ssion mem bers ................................ 500 Bridge rollers a nd rockers .............................................. 250 Pins and pi nholes ........................................................... 125 Sliding bear ings ............................................................. 125
b.Caps and base plates of colu mns, the sole plates of girders and trusses, and other steel components shall fit as required by AWS when assembled. The plates, if warped or deformed, shall be hot-straightened, planed, or otherwise treated to secure an accurate, uniform contact as approved by the Engineer. Correspondingly, the surfaces of base and sole plates which are to come in contact with concrete shall be rough finished and be free from warps or other deformations.
c.Abutting ends of compression members shall, after the members have been fastened, be accurately faced to secure an even bearing when assembled in the structure. (Applicable to truss bridge only.)
d.The contract shall state which ends of tension members at splices shall be faced to provide an even bearing. Where joints are not faced, the opening shall not exceed 1/4 inch (6 mm).
12.Pins and Rollers: a. Pins and rollers shall be accurately manufactured to the contract dimensions and shall be smooth, straight, and free from flaws. The final surface shall be produced by a finishing cut and shall conform to the requirements of Paragraph 11. of this Subsection.
b.Pins and rollers more than 9 inches (225 mm) in diameter shall be forged and annealed. Pins and rollers 9 inches (225 mm) or less in diameter may be either forged and an nealed or cold-finished carbon-steel shafting.
c.Pinholes shall be bored tr ue to detailed dimensions, smooth and straight, at right angles with the axis of the member, and parallel with each other. A finishing cut shall always be made.
d.The diameter of the pinhole s hall not exceed that of the pin by more than 1/50 inch (0.5 mm) for pins 5 inches (125 mm) or less in diameter, or by 1/32 inch (0.75 mm) for larger pins.
708.03 Steel Structures
- 540 - e. The Contractor shall provi de 2 pilot nuts and 2 driving nuts for each size of pin.
13.Thermal Cutting:
a.Structural steel may be thermally cut provided a smooth surface is attained by the use of a mechanical guide. Thermal cutting by hand shall be done only where approved by the Engineer; and the surface shall be made smooth by planing, chipping, or grinding according to ANSI B46.1 Surface Texture.
b.Cuts shall not go beyond the described limit lines. c. Reentrant cuts shall be f illeted to a radius of not less than 1/2 inch (13 mm). Thermal cut surfaces shall meet the ANSI surface roughness rating of 500 micro inches, except members carrying no calculated stress shall meet a rating of 2,000 micro inches.
d.Thermal cut surfaces of me mbers carrying calculated stress shall have their corners rounded to a 1/16 inch (1.5 mm) radius by grinding after thermal cutting.
14.Bent Plates: a. Cold-bent load-carrying rolled-steel plates shall conform to the following:
1.They shall be bent at right angles to the direction of rolling.
2.Cold bending shall be such that no cracking of the plate occurs. Minimum bending radii, measured to the concave face of the metal, are given in Table 708.07. Table 708.07 Minimum Bending Radii Thickness in Inches (millimeters) [t] Up to ¼ (6 mm) Over ¼ to ½ (6 mm to 12 mm) Over ½ to 1 (12 mm to 25 mm) Bending radii for all grades of structural steel 2t 3t 5t
3.If a shorter radius is ess ential, the plates shall be bent hot. Hot bent plates shall conform to the r equirements of Paragraph 14.a. of this Subsection.
4.Before bending, the corners of the plate shall be rounded to a radius of 1/16 inch (1.5 m) throug hout that portion of the plate at which the bending is to occur.
5.Allowance for the springback of Grades 100 and 100W steels should be about 3 times that for Grade 36 steel. For break press forming, the lower die span should be at least 16 times the plate thickness. Multiple hits are advisable. Steel Structures 708.03 - 541 - b. If a radius shorter than the minimum specified for cold bending is essential, the plates shall be bent hot at a temperature not greater than 1,200°F (649°C), except for Grades 70W, 100, and 100W. If Grades 100 and 100W steel plates are to be bent a nd are heated to a temperature greater than 1,100°F (593°C), and if Grade 70W pl ates are heated to a temperature greater than 1,050°F (565°C), they must be requenched and tempered in accordance with the producing mill's standard practices.
15.Fabrication of Steel Girders: a. Welding Procedure: (1) The Contractor shall submit shop drawings for girders and a proposed Welding Procedure Specif ication (WPS) to the Engineer for review before any fabricati on is started. The WPS is maintained on file in the Department.
2.The fabricator may su bmit a WPS directly to the Department’s Bridge Engineer.
3.The WPS shall include the following:
i.Joint description or preparation. (ii) Welding process and type of welding equipment. (iii) Base-metal material specifications. (iv) Welding position. (v) Amperage, voltage, and travel speed. (vi) Type current, polarity, and electrical stickout. (vii) Electrode or electrode-flux classification and manufacturer. (viii) Gas shielding type and flow rate. (ix) Preheat and other heating requirements.
x.Procedure Qualification Record (PQR) used to derive the WPS. (xi) Other data to fully describe the WPS. b. The Contractor shall complete the following work before welding webs to flanges:
1.Butt splices in the flanges and webs shall be welded and radiographed by the fabricator befor e being approved by the Engineer. The maximum number of weld repairs is three.
2.The tee joint shall be freed from carbon, rust, pits, dirt, scale, moisture, and other deleterious material.
3.An external source of heat or force shall be applied to bend the flanges of irregular shaped gird ers. After the heat or the force is removed, the flange shall fit the contour of the web. If heat is used, it shall be limited to a steel temperature of 1, 150°F (621°C). After heating, the metal shall be left to cool at ambient air temperatures above 41°F (5°C) and the velocity of the air shall not exceed 5 mph (8 km/h) throughout the cooling period. Accelerated cooling is not allowed.
708.03 Steel Structures
- 542 - c. (1) The girder material shall be held securely in position during welding, and the welding sequence shall be such as to minimize internal stresses and distortion.
2.Heating and cooling shall be controlled to produce a product within the dimensional tolerances specified.
d.All fillet or groove welds connecting flange plates to web plates shall be made with a submerged-arc automatic welder. Other welds may be made with an automatic, semi-automatic, or manual welder.
e.Unauthorized welds are pr ohibited. The Engineer's written permission is required before producing any temporary or permanent welds not shown in the contract or allowed in the specifications.
f.All repairs must be Pre-Approved and must have a Welding Procedure and a final report submitted.
g.Preassembly:
1.In the shop, preassembly of field connections for steel girders is required to verify the geometry of the completed structure and prepare field joints. The details and methods of preassembly of field connections shall be consistent with the erection plan and blocking diagrams prepared by the Contractor and approved by the Engineer.
2.Camber and blocking tolerances shall be according to AWS Standard Specifications, Section 3.5. 1.3. The span length is the length of girder between the end support and a field splice or between field splices.
3.Only minor weld repairs shall be allowed following preassembly of field connections. Girders placed while checking preassembly of field connections shall have the following items completed: ( i ) W e l d i n g . (ii) Cambering. (iii) Curving. (iv) Straightening.
v.Flattening of bearing surfaces. (vi) Flange Tilt (4) (i) Preassembly of field connections shall consist of 3 or more contiguous girders accurately adjusted for line and camber. Successive segments shall consist of at least 1 girder from the previous assembly plus 2 or more girders at the advancing end. (ii) The Department will approve a 2-girder laydown if the fabricator's shop is too small to handle the 3-girder laydown.
16.Heat Curved Girders: a. Rolled beams and plate gird ers which are manufactured to a specified yield point of 50,000 psi (345 MPa) or less may be heat curved in accordance with the Standard Specific ations when so indicated in the contract. Steel Structures 708.03 - 543 - b. Heating:
1.Heating Procedures are required for the following: (i) Camber Correction (ii) Horizontal Curving of Beams and Girders (iii) Correcting of flange tilt (iv) Web Flatness Correction (2) (i) Beams and girders may be curved by either continuous or V-Type heating as approved by the Engineer. (ii) For the continuous method, a strip along the edge of the top and bottom flanges shall be heat ed simultaneously; the strip shall be of sufficient width and temperature to obtain the required curvature. (iii) For the V-Type heating, the top and bottom flanges shall be heated in truncated triangular or wedge-shaped areas having their base along the flange edge and spaced at regular intervals along each flange. The spacing and temperature shall be as required to obtain the required curvature, and heating shall progress along the top and bottom flanges at approximately the same rate. (iv) For the V-Type heat ing, the apex of the truncated triangular area applied to the inside fl ange surface shall terminate just before the junction of the web and the flange is reached. To avoid unnecessary web distortion, special care shall be taken when heating the inside flange surfaces (the surfaces that intersect the web) so that heat is not applied directly to the web.
v.When the radius of cu rvature is 1,000 feet (305 m) or more, the apex of the truncated tria ngular heating pattern applied to the outside flange surface shall extend to t he juncture of the flange and web. (vi) When the radius of curvature is less than 1,000 feet (305 m), the apex of the truncated tr iangular heating pattern applied to the outside flange surface shall extend past the web for a distance equal to 20% of the flange width or 3 inches (75 mm), whichever is less. (vii) The truncated triangular pattern shall have an included angle of approximately 15 to 30 degrees, but the base of the triangle shall not exceed 10 inches (250 mm). (viii) Variations in the patterns described above may be made with the approval of the Engineer.
3.For both types of heating, the flange edges to be heated are those that will be on the inside of the horizontal curve after cooling. Heating both inside and outside flange surfaces is only mandatory when the flange thickness is 1 1/4 inches (32 mm) or greater, in which case, the 2 surfaces shall be heated concurrently . The maximum temperature shall be 1,150°F (621°C).
c.The girder shall not be artificially cooled, cooled below 41°F, nor shall the velocity of the air exceed 5 mph (8 km/h) throughout the cooling period.
708.03 Steel Structures
- 544 - d. Heating Position:
1.The girder may be heat-curved with the web in either a vertical or a horizontal position.
2.When curved in the vertical position, the girder must be braced or supported so t hat the tendency of the gird er to deflect laterally during the heat-curving process will not ca use the girder to overturn or be damaged.
3.When curved in the horizon tal position, the girder must be supported near its ends and at intermedi ate points, if required, to obtain a uniform curvature. The bending stress in the flanges due to the dead weight of the girder must not exceed the usual allowable design stress.
4.When the girder is positioned horizontally for heating, intermediate safety catch blocks must be maintained at the midlength of the girder within 2 inches (50 mm) of the flanges at all times during the heating process to guard against a sudden sag due to plastic flange buckling.
e.The girder shall be heat-curve d in the fabrication shop before it is painted. The heat-curving operation may be conducted either before or after all the required welding of tr ansverse intermediate stiffeners is completed.
1.However, unless provisions are made for girder shrinkage, connection plates and bearing stiffeners shall be located and attached after heat curving.
2.If longitudinal stiffeners are required, they shall be heat- curved or thermal-cut separately and then welded to the curved girder.
3.When cover plates are to be attached to rolled beams, they may be attached befor e heat curving if the tota l thickness of one flange and cover plate is less than 2 1/2 inches (64 mm) and the radius of curvature is greater than 1,000 feet (305 m).
4.For other rolled beams with cover plates, the beams must be heat-curved before the co ver plates are attached. Cover plates must be either heat-curved or thermal-cut separately and then welded to the curved beam.
f.Girders shall be cambered before heat curving. Camber for rolled beams may be obtained by heat-cambering methods approved by the Engineer. For plate girders, the web shall be cut to the described camber with suitable allowance for shrinkage due to cutting, welding, and heat curving.
g.Tolerance Checking: (1) Horizontal curvature and vertical camber shall not be measured for final acceptance before al l welding and heating operations are completed and the flanges have cool ed to the ambient air temperature.
2.Horizontal curvature shall be measured with the girder blocked with the web in a normal, vertical position.
3.Vertical camber may be measured in an unloaded position. Steel Structures 708.03 - 545 - h. Moderate deviations from sp ecified camber may be corrected by carefully supervised heating subject to the approval of the Engineer.
i.The bearing ends of bearing stiffeners shall be flush and square with the web and shall be connected to the bottom with a full penetration weld. As an alternate, the stiffener shall be ground to bear and attached with fillet welds. Grind to bear shall mean that at least 75% of the area under the stiffener is in contact with the flange. Contact is defined as being such that a 0.001 inch gage will not pass between the stiffener and the flange.
17.Welding: a. The Contractor shall perform all preapproved welding using the following processes; shielded metal-arc, submerged arc, gas metal-arc, or flux cored arc process.
b.Steel Backing: (1) Welds made with the use of steel backing shall have the weld metal thoroughly fused with the backing.
2.Steel backing shall be continuous for the full length of the weld with run-off plates in place. All necessary joints in the steel backing shall have complete joint penetration welds in butt joints.
3.Steel backing of welds t hat are transverse to the direction of computed stress shall be removed, and the joints shall be ground or finished smooth. Steel backing of welds that are parallel to the direction of stress or are not subject to comput ed stress need not be removed, unless specified by the Engineer or shown in the contract. Where the steel backing of longitudinal welds is externally attached to the base metal by welding, such welding shall be continuous for the length of the backing.
c.When back gouging is required, the surface to be welded shall be cleaned of all spatter and ground smooth.
d.Run-off Plates:
1.Run-off plates shall be similar to the plate being welded and be sized to provide a reasonable run-off length and allow adequate heat dissipation.
2.Run-off plates shall be removed when the weld has cooled. The edges of the weld shall be ground smooth and flush with the edges of abutting parts.
e.Tack welds shall not be made outside of the weld area. f. Preheat and interpass temperature shall be sufficient to prevent weld cracking. The minimum preheat and interpass temperature shall be in accordance with AWS Standard Specifications.
g.The Contractor shall match filler metal to base metal in accordance with the AWS Standard Specifications.
h.Aluminum welding shall be done in accordance with the requirements of Section 418.
18.End Welded Studs: Stud welding shall be accomplished in accordance with the AWS D1.5 Standard Specifications Section 7.
708.03 Steel Structures
- 546 - 19. Drip Plates: When drip plates are required on the exterior girders the weld material shall stop 1/2 inch from the end of the drip plat e and 1/2 inch from the edge of the girder. The edges are required to be filled as shown in the contract with a clear colored, 100% silicone product from the Department’s Approved Products List.
20.Steel Diaphragms: a. Flatness or deflection of st eel diaphragms and separators after bending shall not exceed half the thickness of the material being bent.
b.The item "Steel Diaphragms" shall include furnishing and installation of all cross frames, bent plate separators, ang les, plates, bolts, and other incidentals necessary to complete the installation of the diaphragms as shown in the contract.
c.For prestressed concrete gir der structures, all structural steel used in steel diaphragms shall conf orm to the minimum requirements of ASTM A709/A709M, Grade 36 steel, and shall be galvanized in accordance with ASTM A123.
d.Bolts, nuts, and washers shall conform to ASTM A325/A325M and shall be galvanized in accordance with ASTM A153.
21.Shop and Field Inspection: a. The Contractor shall give the Engineer 30 days advanced notice of shop work and provide a copy of the anticipated production schedule. The Engineer will schedule a Prefabrication Meeting at the fabrication shop to review the applic able codes and specifications and the production schedule. The Engineer shall be notified three working days (Saturdays, Sundays, and Holidays are ex cluded) before actual fabrication start time so inspection can be scheduled.
b.The Contractor shall perform inspection and testing at least to the extent specified in the current AWS D1.5 Standard Specifications and additionally as necessary to assure conformance with the requirements of the contract.
c.The Contractor shall facilit ate the inspection of material and work quality in the shop, and the E ngineer shall be allowed free access to the plant.
1.The Contractor shall have the fabricator of main members for structural steel bridges provide an office area for the exclusive use of the Department inspectors assigned to the fabrication plant. The office shall be accessible during all fabrication operations. Parking shall be provided nearby.
2.The office facility shall have a floor area of approximately 110 square feet (10 m 2). It shall be weatherproo f, insulated, lighted, and secured. An office key shall be furnished to each assigned inspector.
3.The office shall be equipped with 115 volt, 60 cycle A/C electrical outlets, telephone with direct outside line and intra-plant capabilities, and a heating-cooling-ventila tion system which circulates clean smoke-free air and will maintain an ambient air temperature of 72°F (22°C). Steel Structures 708.03 - 547 - (4) The office shall be furnished with an office desk [approximately 30 inches (750 mm) x 60 inches (1500 mm)] with drawers, a swivel chair, and a locking storage cabinet.
d.When structural steel is fa bricated outside of Nebraska, the Engineer may elect to make complete inspections of all fabricated work after delivery to the site.
22.Cleaning, Painting and Storage of Material a. Cleaning and Painting of all final structural members with the exception of Cross Frames and Diaphr agms/Separartors shall conform to Section 709.
b.Storage of all final stru ctural members shall conform to Section 106.04.
c.All bearing devices while on the job site must be protected from the elements of weather. Devices sh all either be stored in a job trailer or properly covered with tarps until the devices are put into place. Devices with sole plates and fabric pads require final field inspection by the Bridge Fabrication Manager and approved prior to installation.
23.Marking and Shipping: a. Each structural member shall be scribed or paint marked for identification. An erection drawing shall be furnished showing identification marks.
b.When the weight of a member exceeds 3 tons (3 Mg), then the weight shall be marked on the member.
c.Bolts of one length and di ameter and loose nuts and washers of each size shall be packed separately.
d.Pins, small parts, and small packages of bolts, washers, and nuts shall be shipped in boxes, crates, k egs, or barrels of convenient sizes. An inventory list with a complete description of each item shall be plainly marked on the outside of each shipping container.
e.The loading, transporting, unl oading, and storing of all material shall be conducted so that the material is kept clean and is not damaged.
24.Field Assembly: a. Methods: (1) The Contractor shall request the Engineer's approval of the proposed assembly methods at least 2 NDOT work days before starting the work.
2.Work shall not begin until the Engineer's approval has been obtained.
3.Approval of these methods does not relieve the Contractor of responsibility for performing the work safely in accordance with the contract.
b.The Contractor's preparati on of bearing areas shall include:
1.Contractor shall contact the Department’s Bridge Office a minimum of two weeks prior to installation of Bearing Plates for final inspection.
708.03 Steel Structures
- 548 - (2) Column bases and bearing devices shall have full and uniform bearing upon the substructure concrete. Bearing plates or pads shall not be placed upon bridge seat areas of piers or abutments which are deformed, irregular, or improperly finished.
3.The bearing devices and the bases of columns shall be rigidly and permanently located to t he correct alignment and elevations.
4.A 1/8 inch (3 mm) thick lead sheet shall be placed between all steel and concrete at all areas where a bearing load is transferred. For example, a 1/8 inch (3 mm) lead sheet is required under all pot bearings and special bearings.
5.Anchor bolts shall be cast in the concrete as shown in the contract.
c.The Contractor's methods and equipment used to assemble the structure shall not damage the members. Damaged members shall be rejected.
d.The Contractor shall adjust the structure to its correct grade, alignment, and elevations and confirm splices are properly aligned before installing bolts. The correct camber and relative elevations shall be established before ti ghtening the bolts.
e.The Contractor shall blo ck those girder segments assembled on the ground according to the camber and blocking diagram before bolted field splices are tightened.
f.Plates, angles, and other shapes shall be straightened by methods that will not produce fracture or other damage. Metal shall not be heated unless allowed by the Engin eer. If the Contractor uses heat, a proposal for its use shall be provided. The proposal shall include methods of heating, cooling, and ot her pertinent details.
g.After straightening a bend or buckle, the surface of the metal shall be carefully inspected for evidence of fracture.
h.Corrections: (1) Minor corrections involving reaming, cutting, and chipping are expected. However, any error in the shop fabrication or deformation resulting from handling and transpo rtation which prevents the proper assembling and fitting of parts by the moderate use of drift pins or by a limited reaming, chipping, or cutting shall be reported immediately to the Engineer.
2.Correction using approved methods shall be made in the Engineer's presence.
3.The Contractor shall be re sponsible for all misfits, errors, and damage and shall make the necessary corrections and replacements.
25.Falsework: Falsework shall be designed, constr ucted, and removed as described in Subsection 704.03, Paragraphs 5. and 7.
26.Installation of shear connectors shall be in accordance with ANSI/AASHTO/AWS Bridge Welding Code. Steel Structures 708.05 - 549 - 708.04 -- Method of Measurement
1.a. "Steel Superstructure at St ation _____" is measured as a lump sum.
b.Structural steel for subs tructures and superstructures is measured by the pound (kilogram).
c.Steel diaphragms are measured by the each.
d.Payment quantities are shown in the contract.
2.a. "Steel Superstructure at Station _____", "Structural Steel for Superstructure", and "Structural Steel for Substructure" shall include all structural steel and miscellaneous me tals, except railing and handrails, necessary for the construction as shown in the contract.
b.The weight of structural steel shall be computed by the Department on the basis of the di mensions shown in the contract.
c.In the computation of quantit ies, no deductions will be made for copes, cuts, and open holes, except that in cases of gusset plates, tapered plates, and irregular shaped plates such as the webs and cover plates of tapered columns and the webs of cu rved plate girders, skewed bearing plates, and shim plates, the actual sizes as assembled in the completed structure shall be measured for payment. In the case of rolled plates which have been beveled by milling, payment will be made on the basis of full maximum thick ness throughout.
d.The weight of paint or weld metal on structural steel will not be included in the quantities.
708.05 Basis of Payment
1.P a y I t e m P a y U n i t Steel Superstructure at Station ______ Lump Sum (LS) Structural Steel for Substructure Pound (lb) [ K i l o g r a m ( k g ) ] Structural Steel for Superstructure Pound (lb) [ K i l o g r a m ( k g ) ] Steel Diaphragm Each (ea) 2. Direct payment for arc weldin g and prequalification testing, including all labor, equipment, materials, tools, and incidentals shall not be made but shall be considered subsidiary to the relevant items for which the contract provides direct payment.
3.The cost of furnishing and maintaining an inspection office will not be paid directly, but shall be considered subsidiary to the relevant items for which direct payment will be made.
4.All bolts and fasteners, including anchor and swedge bolts for bearing devices, shall not be paid for directly but shall be considered subsidiary to the various structural steel and steel diaphragm pay items.
5.Payment is full compensation for all work described in this Section. - 550 - SECTION 709 -- PAINTING
709.01 Description
1.The Contractor sha ll prepare the surfaces to be painted, furnish the paint, apply the paint, protect the paint, and dry the paint.
709.02 Material Requirements
1.The Contractor shall furnish a paint system listed on the Department’s Approved Products List or as specified in the contract.
2.The Contractor shall furnish t he paint manufacturer's certification that the paint complies with the paint system specified. T he Contractor shall submit the certification at least 14 days prior to starting the painting.
3.The Contractor shall furnish the Engineer with a complete set of the paint manufacturer’s product data s heets and application procedures. The Contractor shall submit the data sheets and applicat ion procedures at least 14 days prior to starting the painting.
709.03 Construction Methods
1.The Contractor shall pain t structural steel as follows:
a.General: (1) All painting shall be done in strict compliance with the paint manufacturer's recomm endations and the contract.
2.All new structural steel work shall be painted with the system specified in the contract.
3.The exposed surfaces of the steel bearing piles, steel sheet piles, steel pile shells, and stee l pile enclosures above finished ground line or stream bed shall be cleaned and painted with a prime coat. The final coat is not required.
4.All miscellaneous steel, tie rods, armor angles, nose angles, and extrusions for strip seals, except surfaces against which plastic concrete is to be placed, shall be cleaned and painted with a prime coat. The final coat is not required.
5.Weathering steel shall not be painted.
6.Galvanized surfaces shall not be painted.
b.Surface Preparation: (1) All steel surfaces to be painted shall be blast-cleaned to a near-white condition in accordance with The Society for Protective Coatings standard SSPC-SP10. The pictorial refere nce standards contained in SSPC- VIS 1, which correspond to specificat ion SSPC-SP10, may be used to aid the evaluation of t he surface cleaning.
2.The abrasives used shall be clean, dry, sand; steel grit; or iron, steel, or synthetic shot and sh all be of a gradation which produces acceptable results. When shot is used fo r blasting, it must contain sufficient grit to produce a sharp, angular, anchor pattern. If there is not a manufacture’s recommendation, the typica l profile height shall be 2 to 2 1/2 mils (50 to 63 µm). The blasting surfac e profile height shall be in accordance with manufacturer’s recommendations.
Source: Nebraska Standard Specifications for Highway Construction, 2017 Edition. Pages 559–583 of 1,048.