LEED V4 AND STRUCTURAL STEEL

A brief mention of newer LEED v4 credit opportunities reveals that five points can be awarded for the reuse of a historic or abandoned building, and that two to four points can be applied for using materials from an existing building in a new building. In addition, the LEED v4 credit relating to Life Cycle Impact Reduction provides points for reducing the environmental impacts of construction.

However, no credit is provided for the upgrading or expansion of an existing building, which unfortunately is a lost opportunity for structural steel. While it is believed that the reuse of existing foundations would qualify under this credit as “reused” material, simply expanding an existing building or upgrading the facade system for greater energy efficiency would not.

Taking a potentially different approach, some of the experts at the American Institute of Steel Construction suggest that there may be a backdoor to gain credit from the expansion/rehabilitation of an existing structure in that it could be compared to a completely new structure as an alternative in the whole building life-cycle credit section; it would easily meet the criteria of showing environmental improvement in several environmental impact categories strictly on the reduction in material requirements.

AMERICAN INSTITUTE OF STEEL CONSTRUCTION TESTING FOR EXISTING STRUCTURAL STEEL MEMBERS

Offering some guidelines for existing structural steel member testing, the American Institute of Steel Construction relates the following:

• Tensile Properties — Tensile properties of members shall be considered in evaluation by structural analysis or load tests. Such properties shall include the yield stress, tensile strength, and percent elongation. Where available, certified material test reports or certified reports of tests made by the fabricator or a testing laboratory in accordance with ASTM A6/A6M or ASTM A568/A568M, as applicable, shall be permitted for this purpose. Otherwise, tensile tests shall be conducted in accordance with ASTM A370 from samples cut from components of the structure.
• Chemical Composition — Where welding is anticipated for repair or modification of existing structures, the chemical composition of the steel shall be determined for use in preparing a welding procedure specification. Where available, results from certified material test reports or certified reports of tests made by the fabricator or a testing laboratory, in accordance with ASTM procedures, shall be permitted for this purpose. Otherwise, analyses shall be conducted in accordance with ASTM A751 from the samples used to determine tensile properties or from samples taken from the same locations.
• Base Metal Notch Toughness — Where welded tension splices in heavy shapes and plates are critical to the performance of the structure, the Charpy V-notch toughness shall be determined. If the notch toughness so determined does not meet the provisions, the engineer of record shall determine if remedial actions are required.
• Weld Metal — Where structural performance is dependent on existing welded connections, representative samples of weld metal shall be obtained. Chemical analysis and mechanical tests shall be made to characterize the weld metal. A determination shall be made of the magnitude and consequences of imperfections.
• Bolts and Rivets — Representative samples of bolts shall be inspected to determine markings and classifications. Where bolts cannot be properly identified visually, representative samples shall be removed and tested to determine tensile strength in accordance with ASTM F606 or ASTM F606M and the bolt classified accordingly. Alternatively, the assumption that the bolts are ASTM A307 shall be permitted. Rivets shall be assumed to be ASTM A502, Grade 1, unless a higher grade is established through documentation or testing.