Article 1 — Description
Repair steel bridge members , such as beams, girders, diaphragms, trusses, and piling.
Article 2 — Materials
Furnish materials in accordance with the following. Epoxy in accordance with DMS -6100 , “Epoxies and Adhesives” Grout in accordance with Item 421, “Hydraulic Cement Concrete” Replacement steel in accordance with Item 442, “Metal for Structures” Paint in accordance with Item 446, “Field Cleaning and Painting Steel”
Article 3 — Equipment
Provide equipment, including restraining equipment when required, capable of indicating the amount of force applied.
Article 4 — General
Repair or replace steel bridge members in accordance with the plans. Submit a plan that includes the repair method, application of heat and restraint, material, temporary bracing or shoring, and equipment. Obtain approval of the plan before beginning work. Field- weld in accordance with Item 448, “Structural Field Welding.” Perform heat straightening using welding personnel certified for unlimited thickness and all positions in accordance with Item 448. Perform shop fabrication in accordance with Item 441, “Steel Structures ,” excluding Section 441.3.1.5., “Qualification of Plants and Personnel.” Coatings on existing steel contain hazardous materials unless otherwise shown on the plans. Remove paint and dispose of steel coated with paint containing hazardous materials in accordance with Article 6.10., “Hazardous Materials.” Only welders certified or working directly under the supervision of a welder certified in accordance with Item 448 may handle torches when applying heat to steel members. Use drills to place holes in steel members. Ensure torches are not used to place holes unless authorized or as shown on the plans. Do not fill holes with weld metal.
4.1 Heat Straightening . Return all distorted members to their original section, tilt, and straightness by heat
straightening. Use approved mechanical devices to restrain the member while applying heat to straighten the distort ed metal. Ensure mechanical forces are not used to straighten or bend the metal. Ensure impact loads , such as hammer blows , are not applied. Repair cracks as shown on the plans before straightening. Repair minor dents, nicks, and gouges by grinding the defect to an acceptable contour and appearance, with all corners rounded to a 1/16- in. radius. Grind so the finished grinding marks run in the direction of the applied stresses. Straighten steel members to the tolerances shown in Table 1. 1014 Table 1 Straightening Tolerances Greatest Cross- Section Dimension Max Cross- Section Displacement Max Departure from Straightness (per foot of length) >36" 0.5" 0.05" 12–36" 0.375" 0.0375" <12" 0.25" 0.025"
4.1.1 Restraining Force. Apply and lock -off load before applying heat when jacks are used. Limit restraining
forces applied before heating to the values shown on the plans or as approved. Ensure the member is not loaded in a manner that causes material to yield without the application of heat.
4.1.2 Heating P rocess. Heat steel and maintain temperature above 700°F while straightening, but no greater than
1,200°F for typical steel grades, and 1,100°F for quenched and tempered, High-Performance Steel 70W, or 100/100W grade steel. Use only multi- flame heating tips unless approved otherwise, and proportion tip size to the thickness of the material. Manipulate heating torches to guard against overheating. When vee or rectangular heat patterns are used, mark the patterns on the steel before heating. Bring steel within the planned temperature as rapidly as possible without overheating. Guard against buckling when heating relatively thin, wide plates. Closely monitor temperatures using temperature- sensitive crayons, pyrometers, or infrared non-co ntact thermometers. Measure the temperature 5– 10 sec. after the heating flame leaves the area to be tested.
4.1.3 Cooling. Use dry compressed air for cooling after the steel has cooled to below 600°F. Ensure the steel is not cooled with water or mist. Allow the steel to cool below 250°F before applying another set of heating patterns.
4.2 Section Replacement. Replace sections of steel members as shown on the plans or as approved. Use steel backing plates in accordance with AASHTO/AWS D1.5 when placing complete joint penetration groove
welds from one side only. Remove backing plates after completing welding operations.
4.3 Bearing Establishment . Repair areas of incomplete bearing between the slab and the beam by epoxy
injection in accordance with Item 780, “Concrete Crack Repair,” or placement of a grout mixture in accordance with Item 421, as directed.
4.4 Painting . Complete repairs before painting. Paint repaired area only, unless otherwise shown on the plans ,
in accordance with Item 446. Ensure remaining paint adjacent to repaired area is tightly adhering to steel before cleaning and painting repaired area. Match the color of the existing appearance coating.
Article 5 — Measurement
This Item will be measured by each repaired member or lump sum for the entire bridge. A member is defined as one of the following individual components: steel beam or girder over the length of one span, unless otherwise shown on the plans; diaphragm and its connecting hardware between adjacent steel beams; truss vertical; truss diagonal; truss sway brace; piling; or other elements shown on the plans. 1015 6. PAYMENT The work performed and materials furnished in accordance with this Item and measured as provided under “Measurement” will be paid for at the unit price bid for “Steel Member Repair” of the component specified when measured by each member, or for “Steel Structure Repair” when measured by lump sum. This price is full compensation for repairing steel bridge members and steel, grout, epoxy, materials, equipment, labor, tools, and incidentals. No additional payment will be made if the Contractor elects to replace a member indicated to be repaired.