Product Technical Guide Supplement for Seismic Bracing per NFPA 13 April 2020

April 2020

HILTI MECHANICAL ANCHORS AND CAST-IN ANCHORS FOR SEISMIC

BRACING IN ACCORDANCE WITH NFPA 13

Hilti post-installed mechanical anchors and single point cast-in-place anchors are common, cost effective methods for attaching

both structural and non-structural elements to concrete base materials. Non-structural elements, such as fire sprinkler pipes;

electrical conduit and cable trays; heating, ventilation and air conditioning (HVAC) equipment and ductwork are especially suited for

Hilti anchoring systems.

For fire sprinkler pipe applications, Hilti anchors have been effectively used for many years to support the gravity loaded hangers as

well as the sway bracing for resisting the lateral and vertical motion resulting from seismic loads.

Seismic hinge with Hilti anchor

Figure 1 — Typical sprinkler pipe hanger with seismic sway

While Hilti anchors can be designed and installed to support gravity loads of the pipe through the attachment of the hanger to the

concrete, this document will focus on the design of the anchorage to attach the sway brace assembly to the concrete structure.

Contact Hilti for more information related to Hilti anchors to support the vertical pipe hanger.

In a seismic event the earthquake forces are resisted by the transverse and longitudinal sway bracing and the sway braces will

transfer the loads through a fastener that is attached to the concrete. In general, the capacity of the fastener in concrete is dictated

by a design per ACI 318-14 Chapter 17, and the design of the sway brace components is dictated by NFPA 13-16 Section 9.3.5.

Note: For simplicity, this document will reference the 2016 NFPA-13 document sections.

This document will not cover the design of the components of the pipe support hangers or sway bracing. Rather, this document will

provide the maximum horizontal load that can be applied to the sway brace, F

, based on the Hilti fastener type and embedment

depth, fastener load capacity, the concrete strength and configuration, the sway brace to fastener connector (seismic hinge)

geometry, and the brace angle. See Figure 2 on the following page. F

does not consider the adequacy of the seismic hinge or

other components of the sway bracing or vertical hanger. The design engineer of record must ensure all of these components are

suitable for the application and design loads.

This document is a supplement to the Hilti North American Product Technical Guide, Volume 2, Anchor Fastening Technical

Guide, Edition 19 (PTG Ed. 19). Please refer to the publication in its entirety, which is available at www.hilti.com or www.hilti.ca, for

complete details including data development, product specifications, general suitability, installation, corrosion and spacing and

edge distance guidelines, for the Hilti anchoring systems noted within.

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