SECTION 13135 - PREFABRICATED PIPE BRIDGE(s) PART 1 - GENERAL 1.01 Scope A. The Contractor is responsible for all engineering design, detailing, fabricating, installation including foundations for the pipe bridge(s). All components and anchor bolts shall be provided by the fabricator/supplier. The design and detailing shall conform to the Applicable Codes and Standards listed in the section 2 of this document and shall comply with structural drawings/plans and this document. B. Pipe bridge(s) and its attachments shall be fully fabricated by a qualified supplier as outlined in this document. C. Pipe bridge supplier/fabricator shall be responsible for the delivery of all bridge materials including anchor bolts and foundation requirements. Contractor shall construct foundations using the supplier s requirements. D. These specifications are for fully engineered, pre-fabricated pipe bridges(s) of steel construction and shall be regarded as minimum standards for design and construction. E. Fabricator/supplier must meet or exceed all the following specifications. F. The pipe bridge manufacturer shall have been in the design and fabrication of steel bridge or support structures for a minimum of five (5) years. 1.02 Suppliers Documentation to ensure supplier/fabricator shall be in compliance with these specifications must be provided and shall include the following minimum criteria to be considered: Representative Design Calculations Representative Drawings Splicing and Erection Procedures Warranty Information Inspection and Maintenance Procedures Welder Qualifications PART 2 - APPLICABLE CODES AND STANDARDS A. Governing Codes and Standards 1. Bridge(s) shall be designed in accordance with the American Institute of Steel Construction, latest edition 2. Kentucky Building Code, latest edition B. Reference Codes and Standards 1. AASHTO Guide Specifications for the Design of Pedestrian Bridges 2. American Welding Society, Structural Welding Code, D1.1, latest edition C. Truss Design Option Truss design shall maintain the overall dimensions and clearances shown on the plans. Design shall accommodate the proposed utility lines to be attached including weight of contents. PART 3 - GENERAL FEATURES OF DESIGN A. Span Bridge span(s) are variable and are as shown on the plans. A minimum clearance of 18'-0 shall be maintained over roadways or drives. Location of other overhead or adjacent power lines or structures shall be verified to maintain code mandated clearances and avoidance of conflicts. 13135-1
B. W idth Inside clear width of the bridge shall be as shown on the plans. C. Bridge Type 1. Bridge(s) shall be a simple supported, multiple span steel truss, as defined in the structural drawings and this specification, or similar in look and function. Style must be approved in accordance with section 1.1 of this specification. 2. Bridge(s) shall be fabricated and delivered as continuous and pre-assembled structures unless mid-span splices are required for shipping purposes. 3. Bridge(s) shall be designed utilizing lateral and transverse bracing to resist deflection and twisting and increase stability without impeding the ability to attach utility conduits. D. Slope Bridge(s) shall be designed for abutments and/or piers constructed at the same elevation as indicated in the structural drawings/plans. E. Bearing Pads Bridge shall include bearing pads, which shall allow the bridge to expand and contract as needed without binding, in accordance with section 5.3 of this document. F. Bolted Slices Bolted splice design shall be in accordance with Section J3 of the Manual of Steel Construction. Splices shall be designed for the actual load in the member. PART 4 - ENGINEERING 4.01 Design Loads A. Dead Load The bridge shall be designed considering its own dead load including structure and fully loaded attached utility lines. In addition, ice loads shall be considered. B. Point Load The pipe bridge shall be designed for an occasional 1,000 lb point loading. C. Wind Loads 1. Horizontal Wind Load The bridge shall be designed for a horizontal wind load of 90 mph, applied to the full vertical projected area of the bridge as if enclosed, at right angles to the longitudinal axis of the structure. Wind loads shall be proportionally distributed across all exposed primary member surfaces including chords, vertical posts, and truss diagonals on the windward side. Fatigue effects shall be considered for all load combinations incorporating wind loads, where n=100,000 cycles. 2. Overturning Wind Load The effect of forces tending to overturn the structure shall be calculated assuming that the wind direction is at right angles to the longitudinal axis of the structure. In addition, an upward force shall be applied at the windward quarter point of the transverse superstructure width. This force shall be 20 pounds per square foot of projected surface area including pipes. D. Top Chord/Rail Load The top chord, top rail, and vertical posts shall be designed for a simultaneous vertical and horizontal load of 50 pounds per linear foot or a 200 pound point load, whichever is greater, positioned to produce the maximum load effect. 13135-2
4.02 Design Limitations A. Deflection The vertical deflection of the main truss due to any load combination shall not exceed L/500, where L is the length of the unsupported span. The horizontal deflection of the structure due to any load combination shall not exceed L/500, where L is the length of the unsupported span. B. Allowable Stresses All allowable stresses for steel shall be determined in accordance with the AISC Manual of Steel Construction related to design requirements and allowable stresses. C. Frame Stability The buckling load factor for the bridge structure shall be no less than 4 for any combination of applied loads, to ensure adequate overall stability and stiffness. D. Vibration The fundamental frequency of the unloaded bridge shall be no less than 3.0 Hz to avoid the first harmonic. E. Drain Holes W hen the collection of water inside a structural tube is a possibility, the tube shall be provided with a drain hole at its lowest point to let water out. 4.03 Analysis All analysis and results necessary to determine the structural adequacy of the catwalk shall be reported. The following analyses are required: A. Stress and Deflection Analysis shall be completed to determine that all bridge members, critical connections, and bridge configurations are sufficient to adequately resist the possible load combinations B. Frame Stability Buckling analysis shall be completed to determine that the bridge frame is adequately stable and sufficient to resist forces causing it to buckle. C. Frequency Frequency analysis shall be completed to determine that the catwalk frame is sufficient to avoid resonance due to frequencies likely encountered under normal use and when utility lines are empty. PART 5 - MATERIALS 5.01 Structural Members All primary structural members are to be ASTM A36 or A572. Tubular sections to be ASTM A500 Tube steel minimum thickness ¼ Steel shapes minimum thickness 5/16" Stainless Steel U-Bolts ASTM A 276 Chromium-Nickel Grade, min. yield 30,000 psi Steel Bolts, Nuts, Screws and Washers, High Strength ASTM A325 or A490 Structural Steel Welding Electrodes E70 or E80 Series 5.02 Bearing Pads All bearing pads shall be 1/8 thick UHMW adequately dimensioned to provide support to the structure over the full travel resulting from expansion and contraction. 13135-3
5.03 Anchor Bolts Anchor bolt assemblies shall be designed and supplied by the manufacturer in accordance with ASTM A 687. They shall be hot dip galvanized per ASTM A153. Washers shall conform to ASTM F436. PART 6 - FABRICATION & QUALITY ASSURANCE 6.01 Welding All members shall be welded using filler metal in accordance with AWS A5.28 for the GMAW process. W elding and weld procedure qualifications tests shall conform to AW S D1.1. 6.02 Quality Requirements All welds shall be inspected by the fabricator to verify the reliability of production as follows: (a) Visual inspection of all welds, proof testing of welds, and sufficient destructive testing of weld samples fabricated during the production welding. (b) Poor welding workmanship noted by visual inspection will be sufficient cause for rejection. 6.03 CW I Welding Inspector Requirements Each bridge shall be inspected by a Certified Welding Inspector that is qualified under the AWS QC-1 program. This inspection shall include as a minimum requirement the following: review of shop drawings, weld procedures, welder qualifications, and weld testing reports, visual inspection of welds and verification of overall dimensions and geometry of the bridge. A report shall be produced indicating the above items were reviewed and shall be signed and sealed by the CW I signifying compliance with AW S D1.1 codes. 6.04 Welder Qualifications Before starting fabrication of structural steel, all welders shall be qualified in accordance with the latest edition of ANSI/AW S D1.1 Structural W elding Code. W elders shall have a minimum of 6 months experience in welding bridge structures. Requalification may be required any time there is specific reason to question the welder's ability. 6.05 Bridge shall be sandblasted in accordance with SSPC SPC-6 Commercial Blast Cleaning. The bridge will then be painted with an epoxy primer followed by an Aliphatic Urethane Gloss Enamel topcoat. Bridge shall be supplied paint for touch-up after field erection. Primer to be Devoe, Devguard 4160, multipurpose tank and structural primer and finish coat to be Devoe, DTM Urethane - Alkyd Gloss Enamel (3.0 mils dry) or approved equal. PART 7 - SUBMITTALS AND WARRANTY INFORMATION 7.01 Fabrication drawings Fabrication drawings and calculations shall be prepared and submitted for review after receipt of the order. Submittal drawings shall be unique drawings to this project, prepared to illustrate the specific portion of the bridge(s) being fabricated. All relative design information such as member size, material specification, dimensions, and required critical welds shall be clearly shown on the drawings. Drawings shall have cross referenced details and sheet numbers. All drawings shall be stamped, and signed by a Professional Engineer registered in the state of Kentucky. At minimum the following criteria must be included for approval: All Relevant bridge Dimensions Bridge Cross sections Sufficient Detailing Member Cross sections 13135-4
General Notes indicating material specifications and design loads W eld Details Detail of Bolted Splices (if applicable) Foundation Design Signature and Seal of PE licensed in accordance with this specification 7.02 Calculations & Results Structural analysis results and calculations shall be prepared and submitted for review after receipt of the order. All analysis and results necessary to determine the structural adequacy of the bridge shall be shown. 7.03 W arranty The bridge supplier shall warrant the completed structure(s) to be free of design, material and workmanship defects for a period of 10 years from the date of delivery. PART 8 - DELIVERY AND ERECTION 8.01 Owner Information The owner will provide all necessary information about the site and soil conditions. Soil tests shall be procured by the owner. Foundations shall be designed for a soil bearing capacity of 3,500 psf. The engineering design and construction of the bridge abutments, piers and/or footing shall be by the bridge supplier. The Contractor shall install the anchor bolts in accordance with the supplier s anchor bolt spacing dimensions. All grounding and lightning protection shall be the responsibility of the Contractors and shall comply with 2008 National Electrical Code, Chapter 250. 8.02 Care A. Contractor shall take precautions to avoid scarring or marring steel surfaces. Any such damage causing objectionable appearance or contributing to weakness of the structure will be cause for rejection. B. Contractor to remove all milling irregularities. C. Tubing shall be seamless, clean, smooth and free from defects. D. Field check all dimensions before fabrication. 8.03 W eld Quality Regardless of the method of inspection, the acceptance or rejection of welds shall be determined by the following conditions: A. Cracks in welds or adjacent base metal are not acceptable. B. Excess porosity is not acceptable. C. Lack of fusion, incomplete penetration or oxide inclusions are acceptable only if small and well dispersed. End of Section 13135-5