824 Steel Member Thickness, t (in.) Orifice Size W 3 W 4 W 5 W 7 W 8 t > 7/8 * * multi ple torches, rosebud, or multi ple orifice ti ps may be used.
729.09 Suspension of Work 140
If adverse weather conditions such as rain, snow, or hail arise, or anything else causing unexpected or sudden cooling of the heated members, the Engineer may order the suspension of work. If a suspension of work is ordered, the Contractor shall immediately cease applying heat to the steel members. The suspension of work will only apply while adverse weather conditions exist at the project location. The Contractor shall not recommence work until directed by the Engineer.
729.10 Heat Application and Heat Patterns
The Contractor shall identify, by meas urements, all yield zones and yield lines prior to starting heat straightening. The temp erature of the steel member within a heat 150 pattern during any heat straightening cycle shall be between the minimum and maximum temperature values for the respective type of steel shown in the table below. Temperature, °F Type of Steel Shown on the Plans (ASTM Classification Shown) Minimum Maximum 850 950 A709, grade HPS 100W 900 1,000 A709, grade 70W; A709, grade HPS 50W; A709, grade HPS 70W; A852; A913 950 1,050 A514 1,100 1,200 A7; A36; A242; A373; A440; A441; A529; A572; A588; A709, grades 36, 50, 50S, and 50W; A992 Temperatures outside the limits specified above will be cause for rejection and replacement of the steel member. The Contractor shall provide and use one or more of the following devices to verify temperatures during heat straightening: 160
a.Contact pyrometer
b.Infrared non-contact thermometer. The contact pyrometer shall be calibrated daily with temperature crayons prior to use. The infrared non-contact thermometer shall be calibrated every 12 months. 729.09 825 Documentation showing the last date of calibration for the infrared non-contact thermometer shall be provided to the Engineer before use. Heat application shall not be performed unless at least one of the devices listed above is being used to verify the temperature of the steel member. Heat patte rns and sequences shall be selected to match the type of damage and cross-section shape. 170 Heat shall be applied within an included angle of 15 to 55°, but limited to a base width of 12 in. A sufficient number of heat patterns shall be used to eliminate chording effects, where chording effects are define d as straightening small portions of the damaged steel member. Each heat pattern shall be heated in a single pass. The entire heat pattern shall not be reheated until the steel member has cooled below 250 qF. Only cooling with clean, dry air will be allowed. Cooling with compressed air will only be allowed after the steel member has cooled naturally to 600 qF. When the steel member thickness exceeds 1 in., two torches shall be used simultaneously to heat both sides of the heat pattern. The torches shall be located one above the other throughout the 180 heating process. The number, location, and sequence of the areas to be heated shall be marked on the steel members. The following heat patterns shall be used:
a.edge heats
b.line heats (c) spot heats
d.strip heats
e.vee heats. 190 Heat pattern boundaries shall be marked with soapstone. In no case shall heat be applied to undamaged portions of the steel member. When using vee heats, the heat pattern shall be located on the convex side of the steel member. The heat pattern edges shall not overlap and shall be greater than the width of the bottom flange element apart. The apex of the vee should be truncated to an approximate 1 in. width at the junction of the web and flange with the boundaries extending to the edge of th e flange. Once the desired temp erature of the steel member has been obtained, heating shall progress in a serpentine motion from the apex of the 200 vee toward the base of the vee in a single pass.
729.11 Application of Restraining Forces
Restraining forces shall not be app lied without acceptable force measurement systems in place. Force measurement devices shall be calibrated every 12 months. Jacks or come-alongs, not exceeding 25 t capacity, may be used to put steel members into limited compression as a means of mechanically augmenting the heat straightening process. The load shall be applied prior to the application of heat. The load shall not be increased during the heat cycle. Afte r the steel member has been subjected to several heat cycles and has cooled to below 250°F, the load may be 210 adjusted to compensa te for the effects of the heat cycles. 729.11 826 Any section of the steel member that b ecomes distorted, cracked, or permanently deformed due to methods of handling, supporting, loading, or by any other means shall be replaced or repaired as determined by the Engineer.
729.12 Tolerances
The steel member shall be straighten ed to within the following tolerances: Criteria Tolerance Horizontal Sweep 3/8 in. per every 20 ft of length Horizontal Sweep at the point of impact 3/8 in. per every 5 ft of length, or 1/2 in. per every 8 ft of length Vertical Deflection 1/4 in. maximum Deflection of Web (out of plane of web) 1/4 in. maximum in both the vertical and hori zontal direction Tolerances shall be achieved before cros s frames, diaphragms, or any other lateral restraint devices are attached. In no case shall the steel member be forced into position and then welded or bolted to the cross frames or diaphragms to hold the steel member in position. 729.13 Post-Heat Straightening Inspection Following the completion of steel member straightening, the straightened steel member shall be inspected by the Engineer and the Contractor. The inspection shall be performed using the same methods and procedures used in the pre-heat straightening inspection, including performing NDT. 230
729.14 Epoxy Injection
If the top flange of the steel member has pulled away from and is no longer in contact with the concrete bridge deck, the resultant void shall be completely filled by epoxy injection in accordance with 727 after completion of all of the steel member straightening and repairs.
729.15 Painting
Upon completion and acceptance of the h eat straightened steel members, the Contractor shall clean, prime, and paint th e steel members. Surface preparation shall 240 be in accordance with 729.07. The paint system shall be in accordance with 619.09(b). Painting shall be in accordance with 619.10. All exposed surfaces on heat-straightened steel members shall be fully painted from th e edge of the nearest splice plate or steel member end outside the heat straightened area to the nearest splice plate or steel member end on the other side of the heat st raightened area. The color of the top coat shall be a similar color to match the color of the existing bridge. 729.16 Method of Measurement Heat straightening, grinding, drilling crack-arrest holes, NDT testing, and other incidentals will not be measured for payment. 250 729.12 New structural steel and drilled holes for installation of bolts will be measured in accordance with 711.72.
729.17 Basis of Payment
New structural steel and drilled holes for installation of bolts will be paid for in accordance with 711.73. The accepted heat straightened steel members will be paid for at the contract lump sum price for straighten steel member. 260 Payment will be made under: Pay Item Pay Unit Symbol Straighten St eel Member ........................................................... LS The cost for all material, labor, equipm ent, and incidentals for the inspection of the steel members, the temperature verifica tion devices, calibration of the temperature verification devices, grinding, and drilling crack-arrest holes if shown on the plans or 270 directed by the Engineer, shall be included in the cost of straighten steel member. The cost for all NDT activities, including but not limited to all material, equipment, and labor necessary to clean the test areas, perform and interpret NDT, and preparation of all NDT reports shall be included in the cost of straighten steel member. The cost for all materials, labor, eq uipment, and incidentals necessary for disconnecting, supporting, or adjusting the steel members or secondary steel members, jacks or other augmenting devices, the for ce measurement system, and calibration of the force measurement system sh all be included in the cost of straighten steel member. 280 The cost for all materials, labor, equipment, and incidentals required for existing coating removal, preparing, priming, and painting of the steel members shall be included in the cost of straighten steel member. If the Engineer deems it necessary for the Contractor to perform epoxy injection as outlined above, this extra work will be paid for in accordance with 109.05. If, as a result of the Contractor’s methods used in the prosecution of the work, the integrity of the steel member has been co mpromised as determined by the Engineer, 290 all costs to remedy the situation up to and including replacing of the steel members and all costs associated with replacing the steel members shall be at no additional cost to the Department.
Source: Indiana Standard Specifications, 2024 Edition. Pages 841–845 of 1,248.