User Guide

Included: The results depicted in the tool are selected from a pre-defined list of solutions. The auto feature for timber displays the timber solution with optimal performance on the 4 primary outcomes:

• The weight of the system
• The overall structural depth of the system
• The approximate cost of the structure only
• The approximate embodied carbon of the structure

with equal weighting assigned to each of the 4 metrics.

Material assumptions: The list of material assumptions built into the tool are available below in each material’s section: timber, concrete, steel. 

Excluded: While there are other significant metrics, such as schedule/speed, these are subject to too many external variables which are not possible to allow for in a conceptual tool. These additional metrics should be explored with the project team, together with the findings of this tool. 

Caveats: While the tool utilizes advanced and complex finite element analysis of each structural system, since the tool represents a simplified system, it remains conceptual in nature. Keep in mind that the structural floor systems, and all reported data, are approximate and are to be used for conceptual design and material exploration only. Additional adjustments (positive and negative) on the results provided are possible and could be realized through the design process with a licensed structural engineer.

Printing results: If you would like to save your results, select print from your web browser. For best results, set the scale in the print menu to 50% before printing. Another option is to do a screenshot with your computer’s snipping tool and print the image.

By using this application, the user is agreeing to the Terms and Conditions.

Concept only: Outputs are intended for concept purposes only. A licensed structural engineer on the project is responsible for the final design.

Applicable codes and standards: All calculations are performed based on applicable codes and standards.

• BCBC 2018

• CSA O86-14

• CSA S16-14
• CSA A23.3-14

Typical internal bay, no openings: This tool looks at a typical internal bay away from all edges of the building and does not consider openings. Edge and corner bays may have different configurations based on the final design of the project. Continuity is assumed in vibration and deflection studies.

Vibration performance & assumptions: The solutions provided in the tool have been checked at a preliminary level for vibration performance. However detailed calculations are required, and results may change based on specific case-by-case requirements.

Preliminary vibration calculations are done in accordance with AISC Design Guide 11, Second Edition and WoodWorks U.S. Mass timber Floor Vibration Design Guide.

• For the vibration calculations, it is assumed that the point of excitation (i.e. walking path) and point of evaluation (i.e. location of sensitive equipment) are at least 2 m apart.

• Vibration criteria of a maximum peak acceleration of < 0.5%g is used for all conditions.
• For some timber options denoted with an asterisk, additional vibration analysis is required to validate results. Larger member sizes may be required based on actual conditions.

Partitions: Standard partitions non-susceptible to cracking are considered.

Lateral design: No lateral design considerations are included in the calculations as this tool is intended to look at gravity design of an isolated bay within the structure, and the introduction of lateral considerations would develop an uncontrollable range of variables.

Column design: No column design considerations are included in the calculations as this tool is intended to look at an isolated bay within the structure, and variation in height would develop an uncontrollable range of variables.

Column sizes are approximate and based on bay size only.

Fire Protection: Fire protection for timber systems is assumed to be provided through a gypsum ceiling or other means (i.e. any contribution of the mass timber to fire resistance would be incidental, and would not impact the recommended size/thickness).

Governing cases: The governing cases displayed are based on the highest utilization between strength requirements, deflection/serviceability requirements, vibration requirements, and practical structural sizes.

i.e. for completeness, all solutions are provided, however a 3 m x 3 m concrete system with 200 mm thick slabs is known to not be the most practical structural solution.

Embodied carbon data: Conceptual embodied carbon data provided in this tool is for material life cycle stages A1 to A3 (product stage) with a 60-year service life only, with no consideration of end-of-life/disposal. All embodied carbon estimates calculated using Athena Impact Estimator (third-party software), using the embodied carbon values listed in the table below.

Costing data: Conceptual costing data provided in this tool considers the structural material only, delivered, and placed on site. The costing data does not consider construction methods, shipping, protection, and staging of elements (on-site).

• Quantity take-offs are based on the simple typical bay only and values are provided in unit per square area.
• Concrete pricing includes allowance for formwork and reinforcement.
  • Reinforcement ratios shown are based on conventional rules of thumb for the given structural system and are subject to change upon final design.
• Structural steel and timber pricing includes manufacture, fabrication, supply, delivery to site, and complete installation.
• For more details, refer to Costing Assumptions below.

The pricing process in this tool makes no allowance for the speed of construction—while some systems are assumed to have accelerated construction/erection implications, the quantification of this remains subject to the abilities and methodologies of the contractor, as well as the interaction of the assembly with the balance of the construction methods on the project.

It is, however, extremely important to consider the schedule implications of structural material selection, and the ability to monetize any schedule benefits should be discussed with the project team.

Unit pricing is based on the following assumptions:

Location: Vancouver, British Columbia.

Time of estimate: 2024 in the second quarter.

Labour: Union ICI Labour.

Included:

• Prices for delivery to site and complete installation of structural material only.
• Subcontractor (10%) and prime contractor/CM (15%) general conditions, general requirements, bonding/insurances, and OH+P.
• PST.

Not adjusted for:

• Economy of scale.
• Site-specific restrictions and conditions.
• Construction means and methods/method of installation.

Not included:

• Prices for connections and hardware.
• Contingencies (i.e. design contingency, escalation contingency, owners’ contingency, construction change order contingency, etc.).
• Builders’ risk insurance.
• GST.

Unit pricing/rates:

• Unit pricing is approximate and provided for study/research purposes only and may not reflect bid pricing at the time of tender.
• Concrete unit pricing is derived from historical cost data, RSMeans, and vendor quotes include:
  • concrete supply.
  • Plasticizer for high-strength concrete.
  • Environmental tax.
  • Winter heat premium.
  • Summer ice requirements.
  • overtime / small loads / Saturday / other extras.
• Formwork unit pricing is derived from historical cost data, RSMeans, and vendor quotes include:
  • Formwork.
  • Vertical packing.
  • Concrete placing.
  • Concrete finishing.
  • Concrete accessories.
  • Finished slab restoration.
• Unit rates considered in the tool as of June 19, 2024, are as noted below. The unit rates are subject to change based on market conditions and must be confirmed at time of tender by obtaining multiple bids on a completed design by the project’s licensed structural engineer.
• By providing these unit rates, the tool allows the user to make judgements on the conceptual costing data provided in this tool in discussion with their own trusted quantity surveyors, contractors, and other experts.

Structural systems:

• Cross-laminated timber (CLT) concrete composite panels spanning to glulam beams at column lines (no purlins).
  • For short spans, where composite action is not required a conventional CLT panel with non-composite concrete topping is provided in this solution.
• CLT panels with non-composite concrete topping spanning to glulam purlins supported by glulam girders on column lines.
• CLT concrete composite panels spanning to wide flange steel beams at column lines that are moment connected through the columns (no purlins).
  • For short spans, where composite action is not required a conventional CLT panel with non-composite concrete topping is provided in this solution.
• CLT concrete composite panels spanning to wide flange steel beams at column lines that are not moment connected (no purlins).
  • For short spans, where composite action is not required a conventional CLT panel with non-composite concrete topping is provided in this solution.
• CLT panels with non-composite concrete topping spanning to wide flange steel purlins supported on wide flange steel girders that are moment connected through the columns.
• CLT panels with non-composite concrete topping spanning to wide flange steel purlins supported on wide flange steel girders that are not moment connected.
• Flat Soffit option:
  • CLT concrete composite panels spanning to embedded simply supported wide flange steel beams OR two-way point supported CLT panels.
  • For short spans, where composite action is not required a conventional CLT panel with non-composite concrete topping is provided in this solution.

Materials:

• Glulam and CLT grades are included in the design output for each option.
• Concrete strength – 30 MPa, 25% SCM content.
• Timber-concrete connectors to allow for composite action included in the cost/embodied carbon metrics.

Design considerations:

• CLT panels:
  • Target ultimate limit states utilization ratio of 85% used in design.
  • 3-ply CLT with varied concrete topping considered for all solutions containing purlins.
  • CLT concrete composite panels designed with consideration for 254 mm long perforated steel plate connectors glued into the timber panel using epoxy. Connectors are assumed to be approximately 3 mm thick. Approximate number of connectors considered is 10 per m².
  • Timber panels are assumed to have a maximum length of 13 m.
    • For systems with span <= 6.5 m, the floor panels are assumed to be two-span continuous, equally loaded interior panels with consideration for pattern loading. Otherwise, simple-span panels are considered.
    • For the two-span continuous conditions non-composite CLT is considered, and for simply supported conditions timber concrete composite floor systems are considered.
    • Panels may vary based on supplier and shipping constraints; this will need to be validated as a part of the final design.
    • Panel layout is considered staggered so as to limit the amount of added load on purlins due to continuity of the CLT panels. For the purlin design, the tributary area to the purlin is increased by 12.5% to account for these continuity effects of the CLT panels.
  • Additional Notes for Flat Soffit: Point Supported CLT systems:
    • Custom CLT layup consisting of SPF MSR 1950 Fb-1.7E for the outer layers and SPF No.1/No2 for the inner layers.
    • Panels are 3 m wide, and the lamellas are at least 140 mm wide.
    • Panels are continuous over two bays and are point supported at corners and midspan.
    • Full-scale tests are recommended for point supported CLT panels to confirm the allowable spans shown in this tool.
• Glulam beams:
  • Target ultimate limit states utilization ratio of 85% used in design.
  • Glulam beams are assumed to be 15 m in length, maximum and are simple span between columns:
    • Glulam may vary based on supplier and shipping constraints; this will need to be validated as a part of the final design.
    • A maximum depth to width ratio of 3:1 was considered in the selection of the glulam beam sizes to reflect readily available glulam beam sizes in the marketplace.
    • In some cases, the glulam can be placed in two-span continuous conditions, which would likely increase the overall beam volume by up to 10%. This will need to be validated as a part of the final design.
    • Live load reduction was considered in accordance with NBCC 2015 only for the design of long-spanning glulam beams.
  • Camber:
    • Minimum 15 mm, maximum 50 mm, increments = 5 mm.
    • No camber on beams less than 6 m in length.
    • 80-100% of dead load cambered.
• Columns:
  • Not designed:
    • Sizes are based only on bay size and are used to determine clear spans:
      • 266×265 – 6 m span and less.
      • 342×315 – 6.1 m to 8.0 m span.
      • 456×390 – 8.1 m to 10 m span.
• Deflection criteria:
  • Total bay deflection limit after cambering of Span/180 or 40 mm, whichever is less. Span is measured as corner-to-corner distance diagonally across the bay.
  • Live load deflection limit of Span/360.
  • A creep factor of 2 was used to compute long term deflections.

Structural systems:

• Conventionally reinforced concrete flat plate with stud rails; OR
• Conventionally reinforced concrete flat slab with drop panels.

Materials:

• Concrete strength – 35 MPa, GU cement, 25% SCM content.
• CSA G30.18 Grade 400W reinforcing steel.
• ASTM A1044 Grade 350 MPa stud rails.

Design considerations:

• Concrete slab with or without drop panels:
  • Thickness of slab selected to meet punching shear and deflection requirements with consideration for a reasonable level of punching shear reinforcement as noted below.
  • 12 x DECON Studrails with 5 x 12.7 mm spaced at = 150 mm, (OAH = 200 mm).
  • Drop panels are all assumed to be standard size (1/3 of span length).
  • Stud rail designs are conceptual only and are based on interior. columns only. Edge and corner column stud rail design will differ.
  • Target ultimate limit states utilization ratio of 85% used in design.
• Columns:
  • Not designed:
    • Sizes are based only on bay size and are used to determine clear spans.
      • 400×400 – 6 m span and less.
      • 500×500 – 6.1 m to 8.0 m span.
      • 600×600 – 8.1 m to 10 m span.
• Deflection criteria:
  • Total deflection limit after cambering of Span/240 or 40 mm, whichever is less:
    • Span is measured as corner-to-corner distance diagonally across the bay.
  • Live load deflection limit of Span/360.
  • Long term incremental deflection limit of Span/360:
    • Sustained live load is assumed to be 30%.
    • Partitions and other finishes susceptible to cracking are assumed to be installed 1 month after removal of shoring/re-shoring.
• Camber:
  • 15 mm for slabs spans > 7 m and 25 mm for slab spans > 9 m
    • No camber on slab spans less than 7 m in length.

Structural Systems:

• Concrete on steel deck spanning to open web steel joists (OWSJ) supported on wide flange beams.

Materials:

• Concrete strength – 30 MPa, 25% SCM content.
• CSA G40.21 Grade 350W Structural steel for joists and beams.
• ASTM A653/653M Grade 230W Steel deck.
• CSA G30.18 Grade 400W Reinforcing steel.

Design considerations:

• Steel deck:
  • Beam spacing is determined for the concrete on steel deck profile shown, assuming a sheet metal deck thickness of 0.91 mm.
  • Deck is assumed to be laid in triple span.
  • The concrete over steel deck thickness is set by the fire rating requirements for the sector.
  • Un-shored deck construction.
• Steel beams:
  • Target ultimate limit states utilization ratio of 85% used in design.
  • A non-load restricted assembly is used for design.
  • Beam sizes considered are based on the optimal beam sizes provided in the CISC Handbook for Steel Construction:
    • Thus, solutions may exist making use of heavier but shallower beams.
    • Beams are set below joist shoe and so no composite action with the concrete is considered.
• Steel joists:
  • Optimal depth selected based on factored loading (strength) from load tables.
  • Vibration limits met by increasing the area of the chords, while maintaining the joist depth.
• Camber:
  • Minimum 15 mm, maximum 50 mm, increments 5 mm.
  • No camber on beams less than 6 m in length.
  • 80-100% of dead load cambered.
• Steel columns:
  • Not designed:
    • Sizes are used to complete 3D graphics provided.
      • W250x73 for all bay sizes.
• Deflection criteria:
  • Total deflection limit after cambering of Span/240 or 40 mm, whichever is less:
    • Span is measured as corner-to-corner distance diagonally across the bay.
  • Live load deflection limit of Span/360.