PROFIS Engineering Diaphragm Design Guide
1.0 OVERVIEW PROFIS ENGINEERING DIAPHRAGM DESIGN MODULE
The PROFIS Engineering Diaphragm Design Module is a new design module introduced in PROFIS Engineering in 2023 for the design of steel deck diaphragms and concrete filled deck attached to steel structures to transfer lateral loads and uplift loads into the main structural systems. The PROFIS Engineering Diaphragm Design Module has been designed to provide a productive solution for structural engineers to perform code compliant designs.
This design guide is intended to supplement the North American Product Technical Guide Volume 1: Direct Fastening Technical Guide. To see the complete information for Steel Deck products and design information, view the complete Technical Guide at www.hilti.com.
2.0 CODES AND APPROVALS
The Diaphragm Design module is based on the following documents and approvals to perform the engineering calculations for the deck diaphragm designs in the software. Engineering calculations can be displayed in the long report documents that are generated in the software.
| Standard | Title |
|---|---|
| AISI S100 | North American Specification for the Design of Cold-Formed Steel Structural Members |
| AISI S310 | North American Standard for the Design of Profiled Steel Diaphragm Panels |
| SDI DDM04 | Steel Deck Institute Diaphragm Design Manual Edition 4 |
| ESR-2776 | Steel Deck Diaphragms attached with Hilti Powder-Actuated Fasteners and Hilti SLC Sidelap Connectors |
| ESR-3693 | Steel Deck Diaphragms attached with S-MD 12x24 x 1 5/8 M or S-RT5+ Frame Fasteners |
| ESR-2197 | Steel Deck and Concrete Filled Diaphragms Attached with Hilti Fasteners |
3.0 STEEL DECK DIAPHRAGM DESIGN AND THEORY
This design guide is intended to supplement the North American Product Technical Guide Volume 1: Direct Fastening Technical Guide. To see the complete information for Steel Deck products and design information, view the complete Technical Guide at www.hilti.com.
3.1 GENERAL DISCUSSION
A steel deck diaphragm is a horizontal assembly that transfers in-plane forces to the lateral force resisting system of a structure. This includes roof, floors, and other membrane systems. 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.
A diagram illustrating a roof deck diaphragm model, showing forces acting on it, labeled as 'PRESSURE' and 'SUCTION', depicts this concept.
Design of steel deck diaphragms can be done using the Steel Deck Institute (SDI) Diaphragm Design Manual (DDM) or American Iron and Steel Institute (AISI) S310. These methods provide the basic equations for determining the strength and stiffness of the diaphragm considering the following parameters:
- Steel Deck Profile Type and Thickness
- Supporting Steel Frame Spacing or Deck Span
- Frame Fastener Type and Spacing (connector for steel deck to steel frame)
- Sidelap Fastener Type and Spacing (connector for steel deck panel edge to edge)
- Safety Factors (ASD) or Resistance Factors (LRFD/LSD) based on load type (wind, seismic, other) and fastening type (mechanical, weld)
ICC Evaluation Services (ICC-ES) recognizes the AISI S310 design methods as acceptable in AC43, "Acceptance Criteria for Steel Deck Roof and Floor Systems". An ICC Evaluation Service Report (ESR) for a product based on ICC-ES AC43 provides recognition for use with the International Building Code (IBC). Hilti deck fasteners are currently listed in the SDI Deck Design Manual Version 04 (DDM04) and have been evaluated in ICC-ES ESR-3693, ESR- 2776 and ESR-2197. Hilti deck fastener performance with decking systems is also documented in ICC-ES ESR-1169, ESR-2635, ESR-2657 and IAPMO ER-0217, ER-2018, and ER-0329. Additional industry research has shown that metal deck systems, bare and filled, provide a high level of ductility and over strength, when tested as part of a horizontal diaphragm. Metal deck fastened to the structure using specially designed Power-actuated fasteners perform especially well in absorbing excess energy in the inelastic range. The Steel Diaphragm Innovation Initiative, www.steeli.org, has compiled a comprehensive report containing a database of small element and full scale static and cyclic tests.
3.2 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:
- 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
Photographs showing small element connection tests, depicting fasteners connecting steel deck to a base steel member, illustrate these tests.
2. Full scale diaphragm system tests (cantilever tests)
Full scale diaphragm system tests are used to determine the strength and stiffness of a larger steel deck diaphragm assembly directly. The data is analyzed and fit in a predictive model to address varying configurations of base steel, steel deck, specific fastener combinations and spans. These tests are conducted in accordance with the following standards:
- ICC-ES AC43 Acceptance Criteria for Steel Deck Roof and Floor Systems
- AISI S907 Cantilever Test Method for Cold-Formed Steel Diaphragms
- ASTM E455 Standard Test Method for Static Load Testing of Framed Floor or Roof Diaphragm Constructions for Buildings
Schematic diagrams illustrating the test frame setup for ICC-ES AC43 diaphragm tests, showing load application points and connections, are provided. A photograph of a large-scale diaphragm test frame setup at the Fastening Systems Research Laboratory (FSRL) in Schaan, Liechtenstein, is also shown, along with a graph plotting load (in kips) against displacement (in inches) for an AC43 deck diaphragm test, showing a typical load-displacement curve.
3.3 DIAPHRAGM SHEAR AND STIFFNESS CALCULATIONS
An extensive independent laboratory test program was conducted investigating the performance of steel deck diaphragms attached with Hilti fasteners. The program test scope consisted of full scale diaphragm system tests conducted in accordance with ICC-ES AC43 and AISI S907, as well as comparative small element lap-joint shear tests conducted in accordance with AISI S905 Test Methods for Mechanically Fastened Cold-Formed Steel Connections. The resulting full scale and small element test data was analyzed and predictive equations were developed for the steel deck diaphragm system strength and stiffness using specific combinations of Hilti fasteners.
The American Iron and Steel Institute (AISI) Standard for the Design of Profiled Steel Diaphragm Panels (S310) method equations are used as the basis for determining the steel deck diaphragm strength and stiffness. Specific Hilti fastener strength and stiffness values and test data correlation adjustment factors were developed to provide 95% or greater accuracy with test results per ICC-ES AC43 requirements.
The resulting design information is documented in The North American Product Technical Guide Volume 1: Direct Fastening Technical Guide and in ICC-ES ESR-2776, ESR-2197, and ESR-3693.
The data in the aforementioned ICC-ES Reports are then used with the equations found in AISI S310 Section D to calculate diaphragm strength (S) and stiffness (G') or flexibility factor (F) for Hilti X-HSN 24, X-ENP-19 L15, S-RT5+, or S-MD 12-14x1-5/8 M HWH5 (RT5) frame fasteners and Hilti Sidelap Connectors (SLC). The PROFIS Engineering Diaphragm module includes the option to perform the calculations based on AISI S310-16 (adopted by reference in the 2018 and 2021 International Building Code); or AISI S310-20 w/S1-22 (Adopted by reference in the 2024 IBC.) The software is also capable of performing AISI S310 calculations for fastening methods not specific to Hilti such as welding, non-proprietary screws, and button punching of deck.
Uplift and combined loading: The nominal uplift resistance for a given frame fastener and fastening pattern is calculated using methods found in the SDI DDM04 and verified against the uplift demand on the system. For combined loading, when an uplift load is specified by the user, equations are applied from AISI S310 Section D to find the tension effect on shear frame fastener strength. This will result on a reduced diaphragm shear capacity based on the tensile uplift effect.
3.4 DESIGN EXAMPLES
This side-by-side comparison is intended to highlight the benefits of the Hilti full scale test approvals versus the use of standard equations in SDI. The first case uses the Hilti X-HSN 24 and S-SLC 02 Sidelap Fasteners combined in a system as approved under ICC-ES ESR-2776. The second features a similar system using the X-HSN 24 and a #12 drill screw with calculations based on the information found in SDI DDM04. You can see in the Diaphragm shear calculations that the ICC-ESR 2776 values are used with the Hilti Proprietary system rather than the calculated values from SDI DDM 4th Edition for the Frame Fastener and Sidelap Fastener calculations.
Design Example #1: Steel Roof Deck
1 1/2" B-Deck 50 ksi with bar joists at 6' spacing
Nestable deck – 36" panel width
Minimum joist thickness – 0.25"
Design Method – ASD (per AISI S310-20 w/S1-22)
Wind Loads
System Demands:
Diaphragm Shear: Q = 300 plf
Uplift: W = 20 psf
Stiffness G' = 15 kip/in
A diagram shows the system with shear and uplift loads.
| Zone | Deck gauge | Frame fastener pattern | Framer fastener | Sidelap connector | Sidelap connector spacing | Diaphragm shear, Q | Uplift, W | Stiffness, G' | Status |
|---|---|---|---|---|---|---|---|---|---|
| 1 Full Scale Testing | 22 ga | 36/4 | Hilti X-HSN 24 | S-SLC 02 M HWH Sidelap Connector | 24 in o.c. | 355.49 plf | 83.33 psf | 16.59 kip/in | OK |
| 2 SDI Equations | 22 ga | 36/4 | Hilti X-HSN 24 | Hilti #12 Drill Screw | 24 in o.c. | 264.06 plf | 83.33 psf | 16.59 kip/in | Not Recommended |
One or more zones do not meet the design requirements.
Design Checks:
Design Shear: 355.49 plf >= Q = 300.00 plf => OK
Design Uplift: 83.33 psf >= T = 20.00 psf => OK
Shear Stiffness G: 16.59 kip/in >= G' = 15.00 kip/in => OK
Design OK
Design Uplift and Shear-Tension Interaction Calculation for Zone A-1
Nominal uplift resistance:
| Tn,F = Hilti ESR | ICC ESR-2776, Table 10 and 11 | ||||
| Tn = | C (ft) | K | Iv (ft) | Tn,F (lb) | Tn (psf) |
| 3.00 | 3.00 | 6.00 | 1,500 | 250 |
Design uplift resistance:
| Tn,allow = Tn / Ω | Tn (psf) | Ω | Tn,allow (psf) | T (psf) |
| 250 | 3.00 | 83 | 20 |
Tension force per fastener:
| TFF = | C (ft) | K | Iv (ft) | T (psf) | TFF (lb) |
| 3.00 | 3.00 | 6.00 | 20 | 120 |
Roof Deck Construction Handbook
Tension effect on shear frame fastener strength:
QF,red = (1 - TFF / Tn,F) * QF
AISI S310 Eq. D3.1.3-1a
| QF (lb) | TFF (lb) | Tn,F (lb) | Ωup | QF,red (lb) |
| 1,590 | 120 | 1,500 | 3.00 | 1,208 |
Design Checks:
Design Shear: 264.06 plf >= Q = 300.00 plf => Not Recommended
Design Uplift: 83.33 psf >= T = 20.00 psf => OK
Shear Stiffness G: 16.59 kip/in >= G' = 15.00 kip/in => OK
Design Not Recommended
Design Uplift and Shear-Tension Interaction Calculation for Zone A-1
Nominal uplift resistance:
| Tn,F = Hilti ESR | ICC ESR-2776, Table 10 and 11 | ||||
| Tn = | C (ft) | K | Iv (ft) | Tn,F (lb) | Tn (psf) |
| 3.00 | 3.00 | 6.00 | 1,500 | 250 |
Design uplift resistance:
| Tn,allow = Tn / Ω | Tn (psf) | Ω | Tn,allow (psf) | T (psf) |
| 250 | 3.00 | 83 | 20 |
Tension force per fastener:
| TFF = | C (ft) | K | Iv (ft) | T (psf) | TFF (lb) |
| 3.00 | 3.00 | 6.00 | 20 | 120 |
Roof Deck Construction Handbook
Tension effect on shear frame fastener strength:
QF,red = (1 - TFF / Tn,F) * QF
AISI S310 Eq. D3.1.3-1a
| QF (lb) | TFF (lb) | Tn,F (lb) | Ωup | QF,red (lb) |
| 1,489 | 120 | 1,500 | 3.00 | 1,131 |
Design Shear / Stiffness Calculation for Zone A-1
Frame fastener strength:
| QF (lb) | QF,red (lb) | |
|---|---|---|
| ICC ESR-2776, Table 5 | 1,590 | 1,208 |
| SDI DDM, Fourth Edition | 1,489 | 1,131 |
Sidelap connector strength:
| QS (lb) | |
|---|---|
| ICC ESR-2776, Table 5 | 844 |
| AISI S100 Eq. J4.3.1-1 | 636 |
Shear strength calculation:
Formulas for Sne, Sni, Snc, Snp, and Sn are provided, referencing AISI S310 equations.
| A | D (in) | l (ft) | Iv (ft) | N (ft-1) | nd | ne | np | ns | QF (lb) | t (in) | W (in) | wt(in) | (xe)2/W2 | (xp)2/W2 | B | Snc (plf) | Sne (plf) | Sni (plf) | Snp (plf) | Sn (plf) | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | 1.470 | 18.00 | 6.00 | 1.000 | 1.000 | 9.000 | 2 | 9.000 | 1,208 | 0.0295 | 36.000 | 6.000 | 0.556 | 0.556 | 10.731 | 619 | 962 | 692 | 2,417 | 711 | |
| 0.698 | 0.786 | 528 |
Design shear strength:
| Sn,allow = Sn / Ω | Sn (plf) | Ω | Sn,allow (plf) |
| 711 | 2.00 | 355 | |
| 528 | 2.00 | 264 |
Check for buckling:
Formulas for Snb and Snb,allow are provided, referencing AISI S310-20 (Eq. D2.1-1).
| d (in) | I (in4/ft) | Iv (ft) | s (in) | t (in) | Snb (plf) | Ω | Snb,allow | |
|---|---|---|---|---|---|---|---|---|
| 3.000 | 0.178 | 6.00 | 8.189 | 0.0295 | 3,955 | 2.00 | 1,978 | |
| 6.000 | 0.178 | 6.00 | 8.189 | 0.0295 | 3,955 | 2.00 | 1,978 |
Governing:
Sn,gov = Min (Sn,allow, Snb,allow) ≥ Q
| Sn,allow (plf) | Snb,allow (plf) | Sn,gov (plf) | Q (plf) |
|---|---|---|---|
| 355 | 1,978 | 355 | 300 |
| 264 | 1,978 | 264 | 300 |
Frame fastener flexibility:
| SF | t (in) | SF (in/kip) | |
|---|---|---|---|
| Hilti ESR | 0.0073 | ICC ESR-2776, Table 6 | |
| 1.25 / (1000-√t) | 0.0295 | 0.0073 | AISI S310-20 Section D5.2 |
Sidelap connector flexibility:
| SS | t (in) | SS (in/kip) | |
|---|---|---|---|
| Hilti ESR | 0.0175 | ICC ESR-2776, Table 6 | |
| 3 / (1000-√t) | 0.0295 | 0.0175 | AISI S310-20-Section D5.2 |
Shear Stiffness / Flexibility Factor Calculation:
Formulas for G' and F are provided, referencing AISI S310-20 Eq. D5.1.1-1.
| D (in) | d (in) | E (ksi) | I (in) | s (in) | t (in) | W (in) | K1 (in-1) | G' (kip/in) | F (in/kip) |
|---|---|---|---|---|---|---|---|---|---|
| 10,314.600 | 6.000 | 29,500.000 | 216.000 | 8.189 | 0.0295 | 36.000 | 0.0274 | 16.5924 | 0.0603 |
| 10,314.600 | 6.000 | 29,500.000 | 216.000 | 8.189 | 0.0295 | 36.000 | 0.0274 | 16.5924 | 0.0603 |
4.0 CONCRETE FILLED DIAPHRAGM DESIGN AND THEORY
4.1 GENERAL OVERVIEW
Design equations for calculating steel deck diaphragm strength (S) and stiffness (G') or flexibility factor (F) with Hilti X-HSN 24, X-ENP-19 L15 or S-MD 12-24x1-5/8 M HWH5 (RT5) frame fasteners and Hilti Sidelap Connectors (SLC) are utilized in the software. In the calculation report ("Long Report"), the equation numbers correspond to the equation numbers provided in AISI S310.
4.2 DIAPHRAGM SHEAR AND STIFFNESS CALCULATIONS
For concrete filled diaphragms, the equations of AISI S310 Section D4 are used to determine the shear capacity of the diaphragm. The options to complete calculations using AISI S310-16, or AISI S310-20 w/S1-22 are included. Similar to roof deck calculations, users may select a design method from Allowable Stress Design (ASD), Load Resistance Factor Design (LRFD), or Limit States Design (LSD) for these calculations. Uplift is not taken into account for concrete filled diaphragms due to the effect of the concrete weight.
The software features multiple concrete types that users may select when modeling including:
- Lightweight insulation concrete without board in fill
- Lightweight insulation concrete with board in fill
- Structural lightweight concrete
- Structural normalweight concrete
- Structural sand-lightweight concrete
4.3 DESIGN EXAMPLES
Design Example #1: Structural Normal Weight Concrete-filled Deck 3000 psi Normal Weight Concrete
4 inches of concrete fill over the top of a composite deck
2 x12 with bar joists at 6' spacing
Nestable deck – 36" panel width
Minimum joist thickness – 0.25"
Design Method – ASD (per AISI S310-20 w/S1-22)
Wind Loads
Loads:
Diaphragm Shear: Q = 300 plf
Stiffness G' = 15 kip
A diagram shows the system with shear and uplift loads.
| Zone | Deck gauge | Frame fastener pattern | Framer fastener | Sidelap connector | Sidelap connector spacing | Diaphragm shear, Q | Uplift, W | Stiffness, G' | Status |
|---|---|---|---|---|---|---|---|---|---|
| 1 Zone | 22 ga | 36/4 | S-RT5+ Screw | S-SLC 02 M HWH Sidelap Connector | 24 in o.c. | 5498.59 plf | 0.00 psf | 3898.95 kip/in | OK |
Design Shear / Stiffness Calculation for Zone A-1
Frame fastener strength:
QF = 2.7 * t1 * d * Fu1
AISI S100 Eq. J4.3.1-4
| d (psf) | Fu1 (ksi) | t1 (in) | QF (lb) |
| 0.228 | 45 | 0.0295 | 817 |
Sidelap connector strength:
QS = 4.2 * (t3 * d) * Fu1
AISI S100 Eq. J4.3.1-1
| d (in) | Fu1 (ksi) | t (in) | QS (lb) |
| 0.211 | 45 | 0.0295 | 440 |
Shear strength calculation:
Formulas for Sn are provided, referencing AISI S310-20 Eq. D4.1.1-1 through D4.1.1-4 and ACI 318-19- Eq. 19.2.2.1.a.
| b (in) | d (in) | E (psi) | f'c (psi) | s (in) | wc (lb/ft2) | LW | Ec (psi) | nsc | r (in) | tc (in) | ta (in) | Sn (plf) |
| 12.000 | 12.000 | 29,500,000.000 | 3,000 | 14.472 | 145.0 | 1.00 | 3,155,924.251 | 9.347 | 0.0295 | 5.2286 | 5.0000 | 10,997 |
Design shear strength:
| Sn,allow = Sn / Ω | Sn (plf) | Ω | Sn,allow (plf) |
| 10,997 | 2.00 | 5,499 |
Frame fastener flexibility:
| SF | t (in) | SF (in/kip) |
| 1.25 / (1000-√t) | 0.0295 |
Sidelap connector flexibility:
| SS | t (in) | SS (in/kip) |
| 3 / (1000-√t) | 0.0295 | 0.0175 |
Perimeter fasteners calculation:
Formulas for N and ne are provided, referencing AISI S310-16 equations.
| L (ft) | Sn (plf) | QF (lb) | ne | N | |
| 18.00 | 10,997 | 817 | 242.5 | 3.0 | 13.5 |
Note: When shear studs are included, the perimeter fastener spacing may not be relevant. Shear studs are assumed to transfer the diaphragm shear forces to the vertical lateral force resisting elements. The engineer should check the shear studs to determine if there is sufficient capacity for diaphragm forces in addition to composite beam action.
Shear stiffness / flexibility factor calculation:
Formulas for G' and F are provided, referencing AISI S310-20 Section D5.4.
| d (in) | dc (in) | E (psi) | f'c (psi) | I (in) | np | ns | s (in) | SF (in/kip) | SS (in/kip) | t (in) | W (in) | K1 (in-1) | G' (kip/in) | F (in/kip) |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 12.000 | 4.000 | 29,500,000.000 | 3,000 | 216.000 | 2 | 9.000 | 14.472 | 0.0073 | 0.0175 | 0.0295 | 36.000 | 0.0274 | 3,898.9531 | 0.0003 |
5.0 DESIGN OPTIMIZATION AND ALTERNATE SOLUTIONS
The Diaphragm Design Module offers several ways to find cost effective productive solutions to deck diaphragm design problems through design optimization solutions offered in the software. The design optimization feature selects a system based on the total cost of the installed system and offers the most efficient solution based on the loads entered for the design. The end user can allow the software to optimize all parameters against the system demand to get the most optimized result. However, some parameters can be set by other conditions, for example the deck gauge may already be selected to account for snow or dead loads. Therefore the software allows the user to pre-select existing parameters and optimize the system for the remaining parameters. The optimization takes into account the number and cost of the fasteners, the cost of the deck material, the speed of the installation, and returns the most cost-effective system for your project.
You do not need to do a design using the optimization function; however, you may not be using the most cost-effective system for your designs. If you would like to review alternative solutions, you can select the "Other Solutions" button at the bottom of the Zones panel. This allows you to compare alternative solutions to the selected solution whether you have optimized or selected a solution to see other solutions that work for your loads. You can select up to three solutions to be included in the summary table included in the report.
A screenshot of the PROFIS Engineering software interface displaying design parameters and results for diaphragm analysis is shown.
6.0 DEFLECTION CALCULATION
The Diaphragm Design module allows the user to perform a simple deflection calculation of the deck diaphragm using provisions of the SDI Deck Design Manual (DDM 04). The following are the details of different parameters used in Deflection Calculation in the Diaphragm Design Module.
6.1 DEFINITIONS
Angle Area A: The cross-sectional area of the perimeter angle or beam and is used to calculate the Moment of Inertia, I, for a chord steel member.
Wwind: The resulting wind load acting on the area in force per unit length (lb/ft). When the Wwind is defined, the corresponding Flange and Web deflections due to wind load will be calculated.
Wseismic: The resulting seismic load acting on the area in force per unit length (lb/ft). When the Wseismic is defined, the corresponding Flange and Web deflections due to seismic load will be calculated.
6.2 CALCULATIONS
The deck diaphragm deflection (ΔT) is made up of two components, flexural and web deflection. The flexural deflection (ΔF term) is for the perimeter steel beam flange or diaphragm chords, based on classical beam deflection equations. The web deflection (Δw term) is due to the deflection of the steel deck diaphragm itself and is based on the diaphragm shear (q) and the diaphragm shear stiffness (G').
Formulas for ΔT, Δf, and Δw are provided, referencing SDI DDM, Fourth Edition.
where:
- w = entered value from deflection calculation window (wwind or wseismic)
- L = length of diaphragm, perpendicular to the loading direction
- I = moment of inertia of the chord element
- E = is the Young's modulus for steel
- b = width of diaphragm area, parallel to the loading direction
- G' = diaphragm shear stiffness
6.3 DESIGN EXAMPLE
Using the Design Example #1 from the Steel Deck Design examples, see below for the corresponding deflection calculations. The building is assumed to be 500 feet long by 400 feet wide with a L2x2x1/4 perimeter angle (A=0.944 in2). Design loads are 200 plf for wind and 300 plf for seismic. The Zone 2 has been adjusted to use a 12 inch sidelap spacing to allow the design to work for the loads. All other parameters have been maintained.
A screenshot of the PROFIS Engineering software's DEFLECTION CALCULATION interface is shown, detailing area properties and calculated deflections for wind and seismic loads.
Deflections for Design Example #1:
Formulas for Δf and Δw are provided, referencing SDI DDM, Fourth Edition.
| A (in2) | b (ft) | E (ksi) | G' (kip/in) | l (ft) | I (in4) |
|---|---|---|---|---|---|
| 0.944 | 400.0 | 29,500.000 | 16.5924 | 500.0 | 10,874,880.000 |
Deflections (Wind)
| W (plf) | Δf (in) | Δw (in) | Δw + Δf (in) |
| 200 | 0.8767 | 0.9417 | 1.8184 |
Deflections (Seismic)
| W (plf) | Δf (in) | Δw (in) | Δw + Δf (in) |
| 300 | 1.3150 | 1.4125 | 2.7276 |
7.0 FASTENER ESTIMATION
The fastener estimation feature estimates the number of frame and sidelap fasteners needed for the project based on the design parameters for the project.
Frame Fastener Estimation:
The number of frame fasteners is calculated using a formula involving zone area, fastener pattern values (Nffpf), span, and perimeter fastener spacing. Frame fastenings per lineal foot of support member, Nffpf, is calculated based on deck type and fastener pattern.
A table provides sample values for Nffpf for various frame fastening patterns and deck types.
Sample Calculation:
Known: B-Deck, 36/7 pattern (NFFPF = 2) • 4 ft span, 12-inch PFS. A calculation example is shown.
To account for waste, the following equation is used: Total fasteners required = (1 + %waste) * Number of frame fasteners without waste.
A diagram illustrates the diaphragm zone perimeter.
Sidelap Fastener Estimation:
The number of sidelap fasteners is calculated based on whether "number of sidelaps connections" or "sidelap connection spacing" design settings are used. Formulas are provided for both scenarios, incorporating zone area, span, spacing, and waste percentage.
7.1 DESIGN EXAMPLE
Using the same design example from Steel Roof Deck Design Example #1 and the Deflection calculation example in Section 6.3, a fastener estimation has been performed. The zone area for each has been estimated as 100,000 square feet with a perimeter fastener spacing of 6".
A screenshot of the FASTENER ESTIMATION interface is shown, displaying estimated counts for frame and sidelap fasteners for "Full Scale Testing" and "SDI Equations" scenarios.
“Because these counts are only estimated based on the information provided and assumed contingency, the quantities are not guaranteed to be sufficient. Actual requirements will need to be verified onsite to ensure proper quantities are purchased.”
8.0 SPECIFICATION TEXT
PROFIS Engineering provides tools to support structural engineers in creating more accurate design documents such as specification text generated by the software. The Diaphragm Design Module also includes a user-friendly tool to help the user quickly transfer designs to CAD or BIM.
After completing your designs, use the export icon to open the specification text window. This will generate a table of all your designs for each area and zone in a convenient table format for you to quickly export. Select copy to clipboard and you will be able to import the table quickly into your design files to create an attachment schedule or notes to complete your design documents.
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