Heat Straightening Rolled Shapes

Avent, R. Richard; Mukai, David; Robinson, P.

doi:10.1061/(asce)0733-9445(2000)126:7(755)

Cited by 12 publications

(5 citation statements)

References 6 publications

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“…This figure shows that after each damage-repair cycle, the flexural stiffness of the beam decreases and it resistance (strength) increases for larger displacements. This behavior is influenced by the residual stresses produced by the damage and heat straightening repair processes (3,4). The portions of the flanges subjected to high residual stresses undergo yielding at lower loads, which results in reduced flexural stiffness.…”

Section: Damage and Repair Behaviormentioning

confidence: 99%

“…Significant research has been conducted on the heat straightening repair of steel girder bridges. Researchers have conducted experimental investigations to determine the deformations and residual stresses produced by heat straightening (4)(5)(6)8). The results from these studies were used to develop empirical equations and guidelines for conducting heat straightening in the field (2).…”

Section: Introductionmentioning

confidence: 99%

“…Heating is applied by using oxygen-fuel torches, maintaining the steel surface temperature below 650°C (1,200°F) for mild steels and 595°C (1,100°F) for quenched and tempered steels (2,3). Combinations of vee, strip, and spot heats are used to repair the damaged composite steel girders, where vee heats are used to repair the out-of-plane deformations of the flange, strip heats are used to repair the web, and spot heats are used to repair the local buckles and dents (2)(3)(4). Several heating cycles are applied until the residual deformations reach within tolerance levels and the damage is repaired.…”

mentioning

confidence: 99%

“…Significant research has been conducted on the heat-straightening repair of damaged steel shapes (4)(5)(6) and the effects of damage and repair on steel beams (6)(7)(8). On the basis of this research, heatstraightening repair guidelines have been developed by Shanafelt and Horn (9) and Avent and Mukai (2).…”

mentioning

confidence: 99%

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Effects of Multiple Damage-Heat Straightening Repairs on Steel Beams

Kowalkowski¹,

Varma

2007

Transportation Research Record

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Experimental investigations were conducted to evaluate the effects of multiple cycles of damage followed by heat straightening repair on the structural properties and fracture toughness of steel bridge beams. Six W24×76 (or equivalent) beam specimens made from A7, A588, or A36 steel (two beam specimens of each steel type) were subjected to three cycles of damage followed by heat straightening repair. In each cycle, the beam specimens were damaged statically in weak axis bending and were repaired with several half-depth vee heats and an external restraining force. Material specimens were machined from the flanges of the damaged-repaired beam specimens and tested according to ASTM standards. The material test results indicated that multiple damage-repair cycles did not have a significant influence on the elastic modulus, ultimate stress, and surface hardness of the steels. Multiple damage-repair cycles generally increase the yield stress and reduce the ductility of the steels. The Charpy V-notch fracture toughness of A7 and A36 steel beams repaired with maximum heating temperature (Tmax) equal to 650°C was lower than the fracture toughness of the corresponding undamaged steels. The CVN fracture toughness of A588 steel beams repaired with Tmax equal to 650°C and the A36 steel beam repaired with Tmax equal to 760°C was higher than the fracture toughness of the corresponding undamaged steels. Material specimens that were removed from locations closer to the flange-web interface consistently had lower fracture toughness and ductility.

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Section: Damage and Repair Behaviormentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Effects of Multiple Damage-Heat Straightening Repairs on Steel Beams

Kowalkowski¹,

Varma

2007

Transportation Research Record

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“…Prior research has focused mostly on developing efficient heat straightening repair techniques and demonstrating their effective use in the field (4)(5)(6)(7). Limited research has been conducted to evaluate the effects of heat straightening on the structural properties of repaired steel (8,9).…”

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confidence: 99%

Experimental Investigations of the Effects of Multiple Heat Straightening Repair on the Structural Properties of Bridge Steels

Kowalkowski

Varma

2005

Transportation Research Record

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The effects of multiple damage-heat straightening repair cycles (i.e., multiple cycles of damage followed by heat straightening repair) on the fundamental structural properties of typical bridge steels ASTM A36, A588, and A7 were evaluated. The damage and repair parameters considered in the study are the damage strain (ed), the restraining stress (sr), and the number of multiple damage-repair cycles (Nr). The effects of these parameters on the following structural properties were evaluated: elastic modulus, yield stress, ultimate stress, percent elongation, surface hardness, and fracture toughness. Seventy-five laboratory-scale specimens made from A36, A588, or A7 steel were subjected to multiple damage-repair cycles, and their effects on the structural properties were evaluated. The results indicate that multiple damage-repair cycles have a small influence (±15%) on the elastic modulus, yield stress, and ultimate stress. However, the percent elongation and fracture toughness of the damaged-repaired steel are influenced significantly. On the basis of reductions in the percent elongation and fracture toughness, it is recommended that A7 and A36 steel be limited to three damage-heat straightening repair cycles. A588 steel can be subjected to five damage-heat straightening repair cycles.

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