SEISMIC DESIGN SOLUTIONS
Construction solutions for earthquake resistant engineered structures
|Seismic movement is caused by shifts in the earth’s tectonic plates resulting in various levels of surface movement and vibration commonly known as earthquakes. Due to the nature of their movement, earthquakes have the potential to negatively affect the holding capacities of construction products such as concrete anchors, powder actuated fasteners, mechanical and electrical supports as well as the effectiveness of firestop and fire containment systems. |
Therefore, Hilti is pioneering research to extensively test systems for seismic performance in order to support our specifiers and contractors with products capable of withstanding seismic loads. Hilti’s research includes detailed investigation of product performance under simulated earthquake conditions and full-scale system testing. This multi-level approach captures the complexity of fastening system behavior under seismic conditions.
|Post-Installed Seismic Anchor Design |
The International Building Code (IBC) references the anchoring-to-concrete provisions issued by the American Concrete Institute (ACI) in ACI 318 Appendix D Part D.3.3 and ACI 318-14 Chapter 17 Section 17.2.3. This provides methods to calculate the design capacities of anchorages under seismic conditions according to strength design methodology. These provisions apply to structures located in medium-to-high seismic zones (Design Categories C, D, E or F) where the concrete base material shall be assumed to be cracked unless otherwise demonstrated. Similarly, seismic-specific post-installed anchor parameters derived from testing and evaluation per ICC-ES acceptance criteria and ACI test standards are given in ICC-ES Evaluation Reports (ESRs).
To read more on this topic, please visit the Hilti EDucation – Anchors article on Seismic Design
To specify with confidence, view Hilti’s third-party tested and approved products – Approvals & Reports
|Metal Deck Fastening Seismic Design |
Ensuring metal deck panels are securely attached to the supporting structural diaphragm is critically important to the deck’s performance and design shear capacity. Traditionally, arc spot puddle welding has been specified for this application, but there are many limitations to welding roof and floor deck panels. One of the most important factors to consider when designing steel deck diaphragms for cyclical seismic loading conditions is ductility and the system’s ability to dissipate energy during an earthquake.
Hilti’s mechanical powder actuated and screw fastening systems can significantly increase the ductility of the steel deck system as opposed to traditional arc spot puddle welded fastenings. The videos below show a lap-joint shear test comparing a Hilti X-ENP-19 powder actuated deck frame fastener on the left vs a 5/8” diameter arc spot puddle weld on the right, both in 20 gauge steel deck. The graph in the lower right-hand corner plots shear vs displacement where it can clearly be seen that the Hilti fastener’s ductility is far superior compared to the puddle weld.
Hilti Deck Fasteners vs Puddle Weld (Single)
Hilti Deck Fasteners vs Puddle Welds (Double)
Hilti’s X-HSN 24 frame fastener is designed for fastening steel deck to bar joists while the X-ENP-19 frame fastener has the strength to fasten deck to thicker structural beams. Both are approved for design in seismic zones.