Ductility requirements for masonry anchors in high seismic areas
Ductility requirements for masonry anchors in high seismic areas
(OP)
Are there any code provision that require ductile failure modes for cast-in anchors in CMU in high seismic areas? For example with concrete, ACI appendix D clearly outlines the requirement that ductile failure modes must govern anchorage design in SDC C or higher structures or that you can alternatively increase the loads with the overstrength factor. Are there any such code provisions for applying overstrength factors in the design of anchors in CMU for SDC C or higher structures?
Section 14.4.7.6 of ASCE 7-05 states to add the following to section 3.1.6 of ACI 530/TMS 402: Anchorage assemblies connecting masonry elements that are part of the seismic force-resisting system to diaphragms and chords shall be designed so that the strength of the anchor is governed by steel tensile or shear yielding. Alternatively, the anchorage assembly is permitted to be designed so that it is governed by masonry breakout or anchor pullout provided that the anchorage assembly is designed to resist not less than 2.5 times the factored forced transmitted by the assembly.
I'm confused by this section because section 1613 of IBC 2006 excludes chapter 14 of ASCE 7-05.
Section 14.4.7.6 of ASCE 7-05 states to add the following to section 3.1.6 of ACI 530/TMS 402: Anchorage assemblies connecting masonry elements that are part of the seismic force-resisting system to diaphragms and chords shall be designed so that the strength of the anchor is governed by steel tensile or shear yielding. Alternatively, the anchorage assembly is permitted to be designed so that it is governed by masonry breakout or anchor pullout provided that the anchorage assembly is designed to resist not less than 2.5 times the factored forced transmitted by the assembly.
I'm confused by this section because section 1613 of IBC 2006 excludes chapter 14 of ASCE 7-05.
Talk To Other Members
RE: Ductility requirements for masonry anchors in high seismic areas
I will suggest you to look ASCE 7-16 and provide more info. regarding your specific case .
Copy and paste of relevant clause for Non bld structures;
15.4.9.2 Anchors in Masonry.
Anchors in masonry used for nonbuilding structure anchorage shall be designed in accordance with TMS 402. Anchors shall be designed to be governed by the tensile or shear strength of a ductile steel element.
EXCEPTION: Anchors shall be permitted to be designed so that either:
a. the attachment that the anchor is connecting to the structure undergoes ductile yielding at a load level corresponding to
anchor forces not greater than the design strength of the anchor, or
b. the anchors shall be designed to resist the load combinations in accordance with Section 12.4.3 including Ω0 as
given in Tables 15.4-1 and 15.4-2.