Rev. 6-20-96

STRUCTURAL STEEL ASTM A 709 GRADE 50W

711-B-118

The Standard Specifications are revised as follows:

SECTION 711, LINE 334, DELETE AND INSERT AS FOLLOWS:

711.30 Blank Fabricating ASTM A 709M Grade 345W (ASTM A 709 Grade 50W) Steel. This steel shall be left unpainted except as shown on the plans. The finish coat for painted steel shall be in accordance with Federal Color Standard 595a, color No. 30045.

(a) Surface Preparation. A sound uniform surface for the formation of a protective oxide coating on surfaces shall be prepared as described below. The time of surface preparation and the method used shall be at the option of the Contractor, and shall be subject to approval.

1. Hot-Rolled Products. These shall include structural shapes, plates, bars, hot-rolled sheets, and hot-rolled strip. The outside of each facia beam or girder including the bottom of the bottom flange shall be cleaned as set out in the SSPC Surface Preparation Specifications SSPC-SP 10-63T. Contamination from grease, oil, or shop marking shall be avoided. Such surfaces shall be satisfactorily solvent-cleaned.

2. Welded Areas. All exposed welds on facia surfaces shall be prepared by means of power grinding or blast cleaning in accordance with SSPC-SP3-63 or SSPC-SP6-63 to removed welding flux, slag, or spatter.

(b) Fabrication and Handling. Welding shall be in accordance with 711.32.

The fabricator and erector shall handle and store bare steel sections and sub-assemblies so as not to damage them. Scale produced due to welding shall be removed from all exposed surfaces.

Staining by means of concrete, mortar, plaster, oil, paint, grease, food, or other foreign substances shall also be avoided. The use of paints, crayons, or other materials used for identification purposes shall be avoided as they shall be removed during final cleaning of the structure. If the use of such marks is unavoidable, additional cleaning will be required to remove such blemishes. The use of acids to remove scale and stains in the field will not be permitted due to severe pitting which may result from acid concentration at joints and crevices. Storage in transit, in open cars, outside in yards, or on the project site shall be positioned to permit free drainage to avoid moisture pockets which may cause unsightly, uneven weathering.

SECTION 711, LINE 677, DELETE AND INSERT AS FOLLOWS:

711.62 Blank Field Cleaning of ASTM A 709 Grade 345W (ASTM A 709 Grade 50W) Steel. Foreign matter which adheres to steel after it has been blasted, and which inhibits formation of the oxide film shall be removed as soon as practical.

Cleaning of structural steel specified to be left unpainted will not be required except for such cleaning necessary to remove grease, oil, concrete spatter, or foreign matter which affects natural oxidation of the steel. Such cleaning shall be in accordance with SSPC Surface Preparations Specifications SSPC-SP1-63, or SSPC-SP7-63, depending on the severity of the soilage.