The Table of Contents for this section is available.
The work covered by this section consists of the construction of steel structures and the steel structure portions of composite structures in conformity with the lines, grades, and dimensions shown on the plans and as specified in these specifications.
The work also includes the furnishing, fabricating, galvanizing, delivering, erecting, and painting of all structural metals. Structural metals shall include structural steels; metallic electrodes; steel forgings and castings; gray iron and malleable iron castings; drain pipes; and any incidental metal construction not otherwise provided for; all in conformity with the plans and in accordance with these specifications.
Before starting work, the Contractor shall inform the Engineer as to the method of erection he proposes to follow.
440-2 MATERIALS AND FABRICATION.
All materials and their fabrication shall meet the requirements of Division 10 referred to below:
Structural steel Section 1072
Steel pipe Article 1074-5
Welded stud shear connectors Article 1072-8
High strength bolts, nuts, and washers Article 1072-7
Preformed bearing pads. Article 1054-2
Anchor bolts Article 1072-6
Bearing plate assemblies Article 1072-5
Zinc rich paint Article 1080-9
Prints of checked structural steel shop drawings and changes thereto, including shipping diagrams, shall be submitted to the Engineer for distribution or for review, comments, acceptance and distribution as follows:
1. Submit 2 sets for review and comments on all steel structures. After review, submit 8 sets for acceptance and distribution.
2. Submit 5 sets for review and comments for all bridges carrying railroad traffic and after review submit 9 sets for acceptance and distribution.
3. Furnish any additional sets requested by the Engineer for his use, review and/or distribution.
Shop drawings will not be checked by the Engineer except to ascertain general compliance with the design and the specifications. All shop drawings shall be thoroughly checked in all respects by the Contractor. Acceptance of shop drawings by the Engineer shall not relieve the Contractor of his responsibility for the correctness of his drawings, or for the fit of all shop and field connections and anchors.
The maximum size of prints for shop drawings shall be 22" x 36" including borders which shall be at least 1 inch at the left edge of the sheet. Shop drawings may be done in any medium provided they are legible and are capable of giving reproducible prints. Upon completion of the project, the Contractor shall furnish to the Engineer one complete set of reproducible shop drawings that represent the as built condition of the structural steel including all accepted changes if any. The size of these drawings shall be 22" X 36" and they shall become property of the Department.
Changes on shop drawings after acceptance and distribution shall be subject to the review and acceptance of the Engineer and he shall be furnished a record of such changes.
440-4 HANDLING AND STORING MATERIALS.
All structural steel shall be moved, handled, and stored, while in the shop or field and while being transported, so that the metal and any coating will not be damaged and will be kept clean and free of all foreign material such as grease, oil, concrete splatter, chalk marks, crayon marks, and dirt. Natural oxidation of the steel shall not be considered foreign matter.
Material to be stored shall be placed on blocking above the ground. It shall be kept clean and properly drained. Girders and beams shall be hauled upright, placed upright, and shored. Long members, such as columns and chords, shall be supported on blocking placed near enough together to prevent injury from deflection.
The falsework shall be properly designed and substantially constructed and maintained for the loads to which it will be subjected. The Contractor, if required, shall prepare and submit 8 sets of falsework drawings to the Engineer for review, comments and acceptance. Acceptance of the Contractor's drawings shall not be considered as relieving the Contractor of any responsibility.
440-6 BEARINGS AND ANCHORAGES.
Steel masonry plates shall be set level in exact position and shall have full and even bearing on the preformed bearing pad.
Anchor bolts shall be accurately set in accordance with the provisions of Subarticle 42014(A).
Location of anchors and setting of bearings shall take into account any variation from mean temperature at time of setting and anticipated lengthening of bottom flange due to dead load after setting, so that at mean temperature and under dead load the bearings shall be in a vertical position and anchor bolts at expansion bearings will center their slots. Mean temperature shall be 60F. unless otherwise stipulated on the plans. Care shall be taken that full and free movement of the superstructure at the movable bearings is not restricted by improper setting or adjustment of bearings or anchor bolts and nuts.
440-7 STRAIGHTENING BENT MATERIAL.
Straightening bent material shall be done in accordance with Article 107212.
Any error in the shop fabrication, or deformation resulting from handling and transporting, which prevents the proper assembling and fitting up of parts by more than the moderate use of drift pins or by more than a moderate amount of reaming, chipping, or cutting, shall be immediately reported to the Engineer and corrected in his presence by methods which have been approved by him.
Hammering which will injure or distort the members shall not be done.
The drifting during assembling shall be only such as to bring the parts into position, and not sufficient to enlarge the holes or distort the metal. If any holes must be enlarged to admit the bolts, they shall be reamed or corrected by methods which have been approved by the Engineer. Enlargement of the holes will be limited to 1/16 inch over the nominal size hole called for unless the Engineer gives written approval for larger holes.
Bearing surfaces and surfaces to be in permanent contact shall be cleaned and dry to touch before the members are assembled.
Bolted splices and field connections shall have one half of the holes filled with bolts and cylindrical erection pins (half bolts and half pins) before placing permanent fasteners. For continuous units, all beam and girder splices shall be pinned and bolted and the splices brought to the correct elevations before permanent fastening begins. For bolted connections the fit-up bolts and optional shipping bolts shall be of the same nominal diameter as the permanent fasteners, and cylindrical erection pins shall be 1/32 inch larger. Permanent bolts may be used as fit-up bolts.
Temporary bolts, including but not limited to shipping and fit-up bolts, may be supplied with square or hexagon heads and square or hexagon nuts. Hexagon head temporary bolts and nuts are acceptable provided both the head and nut are painted with a durable yellow paint prior to installation.
Reuse of permanent bolts for final installation will not be permitted unless the nut can be easily turned onto the bolt for the full threaded length by hand and without use of tools.
Erection bolts for field welded joints may be used at the Contractor's option. The erection bolts shall meet the requirements of ASTM A325. These bolts are to be supplemented with clamps as necessary to meet the AWS Specifications. The erection bolts shall be galvanized when the finish paint is applied in the structural steel fabrication shop. Where unpainted ASTM A588 structural steel is used, the erection bolts shall meet the requirements of ASTM A325 for type 3 bolts.
After the connection is field welded, the erection bolt shall be left in place and shall have at least the minimum bolt tension shown in Table 440-1. The holes shall be 3/16 inch larger than the nominal erection bolt diameter.
Field welding shall be done only when called for on the plans or when permitted by the Engineer. Welding shall be done in accordance with Article 107220.
Any primer coat of paint at the location of field welds shall be satisfactorily removed by blast cleaning, flame cleaning, or hand or power tool cleaning just prior to performing the welding. Cleaning shall be sufficient to prevent contamination of the weld by the paint.
440-10 CONNECTIONS USING HIGH STRENGTH BOLTS.
(A) General:
This article covers the assembly of structural joints using plain or galvanized high strength carbon steel bolts with suitable nuts and washers tightened to a high tension. Bolt holes shall conform to the requirements of Article 107218.
Bolts, nuts, and washers shall be protected from moisture during storage and shall show no signs of rust at the time of installation.
Plain bolts, nuts, and washers shall have a thin coat of lubricant at the time of installation.
Beeswax, stick paraffin or a lubricant approved by the Engineer shall be applied to the threads of galvanized bolts just prior to installing the bolts.
Bolt, nut and washer (when required) combinations as installed shall be from the same rotational-capacity lot.
The rotational capacity test described in Section 10727(D4) below shall be performed on each rotational-capacity lot prior to the start of bolt installation. Hardened steel washers are required as part of the test.
(B) Bolted Parts:
The slope of surfaces of bolted parts in contact with the bolt head and nut shall not exceed 1:20 with respect to a plane normal to the bolt axis. Bolted parts shall fit solidly together when assembled and shall not be separated by gaskets or any other interposed compressible material. Contact surfaces, including those adjacent to the bolt heads, nuts, or washers, shall be free of scale, dirt, burrs, oil, lacquer, loose rust, rust inhibitor, other foreign material, and other defects that would prevent solid seating of the parts. Paint shall be removed from the contact surface of bolted connections, on curved girder bridges and beam and girder splices.
(C) Installation:
(1) Bolt Tensions:
Each fastener shall be tightened to provide at least the minimum bolt tension shown in Table 440-1. Non-galvanized fasteners shall be tightened by the turn-of-nut tightening method or if permitted, as provided in Subarticle 44010(C)(4), by use of load indicating bolts. Galvanized fasteners shall be tightened by the turn-of-nut method.
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If necessary because of bolt entering and wrench operation clearances, tightening may be done by turning the bolt while the nut is prevented from rotating. Impact wrenches, if used, shall be of adequate capacity and sufficiently supplied with air to perform the required tightening of each bolt in approximately 10 seconds.
(2) Washers:
All fasteners shall have a hardened washer under the element (nut or bolt head) turned in tightening. Galvanized washers shall be used when galvanized nuts and bolts are required. As an exception to the above, special washer requirements for oversize, short-slotted, and long-slotted holes shall be in accordance with Subarticle 107218(H).
Where an outer face of the bolted parts has a slope of more than 1:20 with respect to a plane normal to the bolt axis, a smooth beveled washer shall be used to compensate for the lack of parallelism.
(3) Turn-of-Nut Tightening:
When the turn-of-nut method is used to provide the required bolt tension, there shall first be enough bolts brought to a "snug tight" condition to ensure that the parts of the joint are brought into full contact with each other. Snug tight is defined as the tightness attained by a few impacts of an impact wrench or the full effort of a man using an ordinary spud wrench. Following this initial operation, bolts shall be placed in any remaining holes in the connection and brought to snug tightness. After all bolts in a connection have been brought to snug tightness, each nut, bolt shank, and the structural base metal shall be match marked with a line of white ink or paint that is not water soluble. Additionally, the structural base metal shall be marked to indicate the applicable amount of nut rotation specified in Table 4402. All bolts in the joint shall then be tightened additionally by the applicable amount of nut rotation specified in Table 440-2 with tightening progressing systematically from the most rigid part of the joint to its free edges. During this operation there shall be no rotation of the part not turned by the wrench. To ensure compliance with this article, the match mark on the bolt shank and the initial mark on the structural base metal shall remain aligned. Additionally, the match mark on the nut and the mark representing the specified amount of nut rotation shall be aligned after tightening.
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a Applicable to coarse thread heavy hex structural bolts of all sizes and lengths up to 12 diameters, and heavy hex semi-finished nuts. Nut rotation is relative to the 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.
b When bolt lengths exceed 12 diameters, the required rotation must be determined by actual tests in a suitable tension device simulating the actual conditions.
(4) Load Indicating Bolts:
Tightening by use of a load indicating bolt system is permitted provided it can be demonstrated by an accurate direct measurement procedure that the bolt has been tightened in accordance with Table 4401. Tightening shall be by methods and procedures approved by the Engineer.
(5) Galvanized High Strength Bolts:
Galvanized high strength bolts shall be used in all bolted connections for painted structural steel except for beam and girder splices, cover plate retrofits, or diaphragms and cross-frames on curved girder bridges, unless otherwise noted on the plans.
Galvanized high strength bolts shall be installed with sufficient care so that shop painted surfaces will not be scarred or otherwise damaged.
Galvanized surfaces that are abraded or damaged shall be repaired by thoroughly wire brushing the damaged area and removing all loose and cracked coating, after which the cleaned area shall be given 2 coats of natural color zinc rich paint.
(D) Inspection:
The Engineer shall be given full opportunity to observe installation of bolts to determine that the selected tightening procedure is properly used. The Engineer will determine that bolts are properly tightened and in the case of direct tension indicator bolts that the correct indication of tension has been achieved. Where the turn-of-nut method is used, each bolt will be inspected visually for the correct relationship between the match marks on the nut and the bolt shank. Bolts installed by the turn-of-nut method may reach tensions above the value given in Table 4401 but this will not be cause for rejection. After bolts have been properly tightened, the end of the bolt shall be flush with or extended beyond the outer face of the nut.
Painting shall not begin in the area of tightened bolts until after bolt inspection is completed.
In addition to inspecting for match mark relationship with the turn-of-nut method, the following inspection procedure shall be used unless a more extensive or different inspection procedure is required by the plans or special provisions:
Either the Engineer or the Contractor in the presence of the Engineer, at the Engineer's option, shall use an inspection wrench which shall be furnished by the Contractor and which shall be a torque wrench, calibrated as follows:
At least once each working day, 3 calibration sample bolts of the same grade, size, representative length, and conditions as those under inspection shall be placed individually in a tension indicating calibration device furnished by the Contractor. The tension indicating calibration device shall have been certified by the Materials and Tests Unit, within 6 calendar months prior to testing the bolts under inspection, to be in good working order and to provide accuracy within plus or minus 10 percent for the range of loads between 25,000 and 40,000 pounds. There shall be a washer under the part turned in tightening each bolt if washers are so used in the structure. If no washer is used the material abutting the part turned shall be the same as that used in the structure.
Each calibration sample bolt shall be tightened in the calibration device by any convenient means to an initial condition equal to 15 percent of the required tension and then to the minimum tension specified for its size in Table 440-1. The inspecting wrench then shall be applied to the tightened bolt and the torque necessary to turn the nut or head 5 degrees (approximately 1 inch at 12 inch radius) in tightening direction shall be determined. The average torque measured in the tests of 3 bolts shall be taken as the job inspecting torque.
Bolts, represented by the calibration sample bolts, which have been tightened in the structure shall be inspected by applying, in the tightening direction with the inspection wrench, the job inspecting torque to 10 percent of the bolts, but not less than 2 bolts, selected at random in each connection. If no nut or bolt head is turned by this application of the job inspecting torque, the connection will be accepted as properly tightened. If any nut or bolt head is turned by the application of the job inspecting torque, this torque shall be applied to all bolts in the connection, and all bolts whose nut or head is turned by the job inspecting torque shall be tightened and reinspected, or alternatively, the Fabricator or Erector, at his option, may retighten all the bolts in the connection and then resubmit the connection for the specified inspection.
All cleaning and painting of iron and steel surfaces shall be in accordance with the provisions of Section 442.
Galvanized surfaces which have been abraded or damaged shall be repaired in accordance with Article 10766.
440-12 SURFACE PREPARATION AND PROTECTION OF UNPAINTED STRUCTURAL STEEL.
All structural steel which is to remain in the unpainted condition in the completed structure shall be shop cleaned after fabrication in accordance with Subarticle 442-8(B), except that contact surfaces and 1 inch beyond in the plane of contact of high strength bolted joints shall be near white blast cleaned in accordance with Subarticle 442-8(A). Contact surface condition shall be in accordance with Subarticle 440-10(B) at the time bolts are installed.
In addition to the above cleaning requirements, on all bridges except stream crossings, the outside surfaces of exterior girders (web, bottom of top flange, top and bottom of bottomflange and outside edge of bottom flange) shall be given a near white blast cleaning (SSPC-SP10) in the fabrication shop.
The structural steel shall be protected during concreting and any other operations that are likely to be particularly hazardous with respect to soiling the steel. Any foreign matter which gets on the steel is to be removed as soon as possible by either solvent cleaning, hand tool cleaning, power tool cleaning, blast cleaning, or a combination thereof, as necessary to restore the surfaces to the specified condition.
Structural steel will be paid for at the contract lump sum price for "Approximately _____________Pounds Structural Steel". The approximate quantity shown in the contract pay item is an estimate based on the computed weight of the structural steel necessary to complete the work. No measurement for payment will be made for this pay item, and no adjustment in the contract lump sum price will be made for any variation from the approximate quantity shown except for revisions in the plans which affect the quantity of structural steel necessary to complete the work.
When revisions in the plans have been made which affect the quantities of structural steel, adjustments in compensation will be made by supplemental agreement.
When the contract includes the item of "Painting of Structural Steel", all work of painting except for shop painting will be paid for as provided in Article 44213 and payment for shop painting will be included in the contract lump sum price for "Approximately __________Pounds Structural Steel". When the contract does not include the item of "Painting of Structural Steel", payment at the contract lump sum price for "Approximately __________Pounds Structural Steel" will be full compensation for both shop and field painting.
The above prices and payments will be full compensation for all work covered by this section including but not limited to furnishing, fabricating, galvanizing, delivering, placing, erecting, cleaning, shop painting, and field painting structural metals and all other materials; furnishing, erecting, and removing falsework; setting bearings and anchorages; welding; and assembling all structural joints.
Payment will be made under:
Approximately _____________Pounds Structural Steel Lump Sum