Steel Deck Fastening Systems
1.1 Steel Deck Fastener Design and Selection
1.1.2 Steel Deck Diaphragm Design and Theory
1.1.2.1 General Discussion
A steel deck diaphragm is a horizontal assembly that resists
wind, seismic and other lateral forces. A diaphragm can
be modeled as a horizontal beam with interconnected floor
and roof deck units that act as the beam web. Intermediate
joists or beams act as web stiffeners and perimeter beams or
reinforcement on the diaphragm perimeter act as the beam
flanges. Figure 1, based on graphics from the Steel Deck
Institute (SDI) Diaphragm Design Manual, depicts a roof deck
diaphragm model.
Design of steel deck diaphragms has traditionally been
done using the Steel Deck Institute (SDI) Diaphragm Design
Manual or Technical Manual (TM) 5-809-10 Seismic Design
for Buildings, Departments of the Army, Navy and Air Force
(Tri-Services Design Manual). Both methods provide the basic
equations for determining the strength and stiffness of the
diaphragm considering the following parameters:
1. Steel Deck Profile Type and Thickness
2. Supporting Steel Frame Spacing or Deck Span
3. Frame Fastener Type and Spacing (connector for steel
deck to steel frame)
4. Sidelap Fastener Type and Spacing (connector for steel
deck panel edge to edge)
5. Safety Factors (ASD) or Resistance Factors (LRFD/LSD)
based on load type (wind, seismic, other) and fastening
type (mechanical, weld)
ICC Evaluation Services recognizes both design methods
as acceptable in AC43, Acceptance Criteria for Steel
Deck Roof and Floor Systems. An ICC Evaluation Service
Report (ESR) based on ICC-ES AC43 provides recognition
for use with the IBC. Hilti deck fasteners are currently listed
in the SDI DDM03 and Appendix VI, VII and VIII and were
evaluated in ICC-ES ESR-3592, ESR-2776 and ESR-2197.
Hilti deck fastener performance with proprietary sidelap
clinching systems is also documented in ESR-1735P,
ESR-1116, ESR-1169, ESR-1414 and ESR-2408. Additional
industry research on quasi-static and seismic/cyclic load
performance of diaphragms is ongoing. Other system
approvals and evaluation reports are pending.
Figure 1: Diaphragm Model
1.1.2.2 Fastener Test Programs
Many small element and full scale test programs have
been conducted using Hilti deck fasteners to evaluate their
performance.
1. Small Element Connection Tests
Small element connection tests are used to determine
fastener pullout, pullover and lap-joint shear strength and
stiffness with sheet steel and base steel representative of
typical construction. The data is analyzed and used in a
predictive model to calculate the performance of the larger
steel deck diaphragm assembly or system. These tests are
conducted in accordance with the following standards, and
shown in Figure 2.
• AISI S905 Test Methods for Mechanically Fastened Cold-
Formed Steel Connections
• ASTM E1190 Standard Test Methods for Strength of
Power-Actuated Fasteners Installed In Structural Members
• ICC-ES AC70 Acceptance Criteria for Fasteners Power
Driven Into Concrete, Steel and Masonry Elements
• ICC-ES AC118 Acceptance Criteria for Tapping Screw
Fasteners
4 Hilti, Inc. (US) 1-800-879-8000 | www.us.hilti.com I en español 1-800-879-5000 I Hilti (Canada) Corp. 1-800-363-4458 I www.hilti.ca I PTG Decking Supplement 2014