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Cable Fittings that Can Damage the Cable Violate Building Codes

The International Building Code (IBC) requires earthquake protection of non-structural building components and cites the Standards with which compliance is required. The Code referenced Standards are made part of the Building Code. This is done in Section 102.4 of the International Building Code.

Section 2208 of the IBC requires compliance with ASCE 19 for steel cables that are used to satisfy the requirements of the Code. ASCE 19 is the only steel cable Standard that is referenced by the IBC. Section 1613 of the IBC requires earthquake protection of non-structural building components and requires the design and construction in accordance with ASCE 7. ASCE 19 is also the only steel cable Standard that is referenced by the ASCE 7.

Background

Prior to 1996, the only Building Code referenced Standard for steel cables was published by the American Iron and Steel Institute (AISI) with the title Structural Applications of Steel Cables for Buildings. The AISI document dated back to at least 1973 and, among other things, required that the fittings used in cable assemblies develop the minimum breaking strength of the cable itself. This was to insure that the fittings would not damage the cable and make it break early. Contrary to the practice of some, the Standard has never allowed the use of larger safety factors to be used in circumvention of this requirement.

American Society of Civil Engineers (ASCE) took over responsibility for this Standard in 1996 with the publication of ASCE 19-96 Structural Applications of Steel Cables for Buildings. ASCE 19 has also always required that the fittings used in the cable assemblies develop the minimum breaking strength of the cable itself.

The Issue

This is the issue with the fittings. If the cable itself maintains the required minimum breaking strength but the cable assembly breaks early after a fitting is installed in the cable assembly, then the fitting damaged the cable and the damage occurred at the time that the fitting was installed. It then follows that the amount of damage cannot be predicted, because it will vary with the skill and strength of the installer.

“U” shaped cable clips and cable fittings that employ a wedge to keep the cable from slipping are notorious for damaging the cable and/or loosening over time. While I was not on the ASCE 19 Committee when it was done, I can confirm the acceptance of such cable fittings was removed from the 2010 Edition of ASCE 19 and thus they cannot be used to satisfy the requirements of the IBC or ASCE 7 for earthquake sway bracing. ASCE has issued a Formal Interpretation on ASCE 19-10 Section 5.3 with an effective date of May 24, 2012 confirming the prohibition of these types of cable fittings and it can be viewed here http://ascelibrary.org/doi/pdf/10.1061/9780784411247.int.

– Daniel C. Duggan, ASCE 19 Committee Member

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