This Second Edition of Technical Digest 12 is another addition to the series of Steel Joist Institute publications designed to give the reader information regarding the application and usage of steel joists and joist girders. Technical Digest 12 concerns itself with the evaluation of existing steel joists and joist girders to carry additional loads not accounted for in their original design. The technical digest also addresses situations where the configuration and/or the original geometry of the steel joists or joist girders need to be modified in the field.

The latest updates to Technical Digest 12 include:

• Bearing seat analysis and reinforcement; consider adding stiffeners.
• Cold formed chord sections (historical); how to modify, strengthen.
• Analysis of rusting chords; how to measure damage/strength.
• Establishing load capacity of under-length joist; one with load not shown in the table.
• Shoring.
• Use of intermediate supports at bottom chord; shorten the span.
• Reinforcement of double round chord member.
• Removal or relocation of bridging.
• Analysis of fire-damaged joist.
• Updated investigation form.
• Proper field measurements.
• Recommendation on determining yield strength.
• Evaluating an overloaded joist.
• Evaluating change in uplift requirements.