Why seismic consideration important to designers?

Seismic strength checks are required for connections involving both structural and non-structural elements. Structural connections INTEGRITY are vital to ensure safety under seismic loading component especially for buildings whose integrity is of vital importance for civil protection.​ Seismic loading induces extreme load conditions in fastenings much above concrete cracks.

During an earthquake, the anchors will need to cope with:​



With the launch and introduction of NSCP 7th edition in relation to ACI 318-14.  We can now calculate/ assess anchors on its suitability in seismic condition​. It now offers full coverage in designing post installed anchoring with the inclusion of qualification for SEISMIC SUITABILITY​.



And with that, We can actually determine the design resistance of a fastener  in concrete considering seismic condition The designer may now perform the Concrete Capacity Design Method according to ACI 318-14 Chapter 17 where the anchor‘s design resistances are derived from the ICC Evaluation Service Reports of the relevant anchor. The design steel strength in tension is already given in the ESR relevant design table. The design concrete breakout strength in tension is identical in getting design strength of anchor in static but multiplied by 0.75 reduction factor to consider seismic. Likewise, design pullout/bond strength in tension is also identical in the getting the design strength of anchor in static but then again multiplied by a reduction factor of 0.75 to consider seismic. 

There is actually no provision for ductile failure of the anchor element in shear. Since Connection governed by failure of the fixture, and we know Connections are usually designed for non ductile failure modes. The design concrete breakout strength and design pryout strength in shear is also identical in getting the design strength of anchor in static. We do not apply reduction factor of 0.75 for that matter.