Software solutions for LVL building systems

Cameron RodgerB.Eng(Civil), MIEAust, MIPENZ, CPENGLVL Business Manager

Agenda• Laminated Veneer Lumber• Material Selection• LVL building design guidelines• Timber engineering design tools - computeIT Suite • Whangarei Dry Mill – a practical design example using

computeIT toolkIT• I-beam purlin design• Box beam design• Solid rafter design• Practical considerations

• Real examples • TCC Floor Design using computeIT for beams

Laminated Veneer Lumber (L.V.L)• CHH Engineered Wood Products range

– Structural LVL – hyONE (E=16.0), hySPAN+ (E=14.0), hySPAN (E=13.2), hyCHORD (E=11.0), hy90(E=9.5), hyJOIST

– Use higher grade LVL for primary structural members– Use i-beams or lower grade LVL for secondary framing

• Features and benefits– Sourced from renewable plantation pine

• Consistent quality raw material availability, carbon storing helping reduce green house gas omissions• Available FSC Certified

– Manufacturing process 3rd party audited• Guaranteed consistent quality

– Peeled veneer eliminating naturally occurring defects• Removes localised stress raisers such as knots, etc.• Veneer tested for stiffness and recipes established for each product

Structural L.V.L• LVL is an engineered material with the

intrinsic benefits of timber

• Suitable for use in fully integrated LVL systems including:– Built up LVL portal frame components– Composite plywood and LVL purlins– LVL wall framing– TCC Floors– Multi-Storey Structural Systems

• Designers can have confidence that the design intent will carry through to the finished structure

LVL - Material selectionLVL ideal material choice due to adaptability in:

– Structural reliability/variability– Production lengths – Limitless (18.3 m

practically)– Sections sawn from nominal 1200 mm billet– Thickness variation

• Ranging from 28 mm to 105 mm– Type of LVL

• Long band• Cross band

– Allows for creation of built up sections• Box Beams • Deep I-beams

Portal Suite - Material selection

• Cross Band LVL– Dimensional Stability.– Reduces tendency of long band veneers to split from

fasteners– Limited stocks readily available, largely a made to order

product

LVL Building design guidelines

• Design methodology and loading– Design criteria based on structure type not material type– Loading in accordance with relevant loading standards– Footing and bracing design similar to steel systems

• Footing sizes an have significant savings in relation to concrete buildings

– Optimal member spans and bay/frame spacings may be different for timber, steel and concrete structural systems

LVL Building design guidelines

• Elastic Structural Analysis (Microstran, Spacegass) differs little to that applied to steel except for structural properties

• No separate consideration of shear deflection required for solid LVL sections– For built up sections adjustments to Poisons ratio required

• A number of options for rigid moment resisting connections– X-banded LVL gussets– Quick connect jointing system– Post tension/pre-stressed structural systems

• Serviceability limits similar to steel and concrete • Effects of creep need to be taken into account for

permanent loads

Design Tools

CHH have produced tools to aid in the design of LVL based systems

• Software based solutions– computeIT for beams

• Now includes TCC Floor Design– computeIT toolkIT

• Rigid moment connection design• Member design (solid and built up sections)• Purlin Design • Girt Design

– Includes Design details, commonly available products and connections

• Alternate commercial product range• Engineering support from experienced consulting

timber design engineers

computeIT Suite

1. Provides LVL Structural solutions for market segments currently limited to EWP’s through engineering design capability/costs

2. Make the design of timber based systems and connections as easy, or easier than steel alternatives

3. Presents proven, cost effective solutions from readily available LVL members

4. Developed by practicing timber design engineers for engineers

5. Interactive design in accordance with regulatory design standards

6. Design modules that aid engineers in the interpretation of timber phenomena

7. Still allows the design engineer to make the decision about the suitability of design

computeIT for beams

An integrated design and analysis package for engineers. Aids engineers in the understanding of

timber design and analysis.Target Market

– All engineers (those not comfortable with ‘black box’ packages) currently using structural analysis

packages and steel solutions– residential & commercial projects

computeIT for beams

• Point of difference– Design & Analysis Package

• Allows for entry of predetermined loads for beam designs for all types of loading for differing beam configurations

• Design and analysis for both strength and serviceability limit states

– Un-factored loads entered– Factored load cases presented as per AS/NZS 1170.1– Users enter restraint condition– Design in accordance with AS1720– Provides guidance for engineers in relation to timber phenomenon's

» Shear Deflection» Creep» Duration of load

– Importantly, still allows engineer to make the decision about the suitability of the section

computeIT for beams- Now includes EXPAN/STIC technology

Timber Concrete Composite (TCC Floors) providing composite action between concrete and LVL structural

elements. Key Value Proposition

Provide a structurally fit for purpose solution that includes a level of fire resistance and acoustic

attenuation.

computeIT toolkIT

computeIT toolkit is a series of design tools to allow for the quick and easy design of rigid moment

connections, primary and secondary members

Target Market – engineers design commercial and industrial buildings

computeIT toolkIT

Point of difference:– computeIT toolkit provides users with the opportunity to:

• design moment resisting connections with commonly available materials and connectors

• design solid and built up members subject to combined actions, easily considering the effects of alternate restraint options

• Load combinations to AS/NZS 1170, with automatic selection of duration of load factor

• analyse different members to determine cost effective options• design solid and i-beam purlins and girts, including support and restraint

details• create a job specific Engineering Analysis Report including designed

members and connections• Provides guidance for engineers in relation to timber phenomenon's

– Direction of grain– Duration of load

• Review full worked design examples to aid engineers with the adoption of timber engineering

computeIT toolkIT - Now includes EXPAN/STIC technology

Quick Connect moment resisting connection design technology is now included in computeIT toolkIT. 

Key Value PropositionThe quick connect technology uses a threaded rod,

washers and nuts for ease of connection on site through factory fitted LVL sleeves.

computeIT for PORTAL FRAMES – under development

computeIT for PORTAL FRAMES is a fully integrated design, detailing, specification, and takeoff package

for the design of LVL based portal frames

Target Market – engineers designing portal frame systems

- fabricators (costing and fabrication)

www.chhsoftware.com

Whangarei Dry Mill – A practical design example

• A practical engineering approach including:– Use of box and solid sections– I-beam purlin design options– Optimisation of material usage (and

cost) • Fabrication

– Importance of using an experienced fabricator

• Peace of mind• Kit-set delivery

– Large solid section vs lower volume built up section

• Erection methodology– Bay lifts

• Program advantages• OH&S advantages

Whangarei Dry Mill

• Cost effective and structurally efficient design to develop a 12,210 m2 building

• Member selection based on:– Structural integrity, – Material availably, and – Level of fabrication expertise required

• Versatility of LVL allowed development of a frame with:– Built up box beams that have cross banded (x-band) LVL webs

and LVL flanges in high moment regions– 18.2 m long solid 105 mm thick LVL sections in reduced

moment regions, reducing fabrication time and cost.– Off the shelf I-beam purlins at 10 m bays completed the large

manufacturing and storage facility.

Whangarei Dry Mill – Building footprint

Whangarei Dry Mill – Elevations

Two portal frames proposed to share ridge line

Whangarei Dry Mill

Whangarei Dry Mill

Whangarei Dry Mill – Purlin Layout

Whangarei Dry Mill – Purlin Design

1. Reduced spacing– Increased number of components– More on site connections

2. Increase flange size/capacity as required– Typical for large buildings– Eliminates multiple spacing adjustments– Capability to manufacture ‘specifically

designed’ I beams.

3. Increase number of lateral restraints

Solution : Mixture of reduced spacing and increased flange size provides optimum design solution

Purlins within proximity of building edge subject to localised pressure & require:

I-beam Purlin DesignRegion Within ‘a’ from

windward edgeWithin ‘h’ from windward edge

Span 10000-193 = 9807 10000-105 = 9895

Spacing (max) 1380 1600

Roof Mass

Roof sheeting mass

6.5 kg/m2 6.5 kg/m2

Miscellaneous 2.0 kg/m2 2.0 kg/m2

Wind Loading

weff -1.74 kN/m/m# -1.10 kN/m/m#

R* -8.36 kN/m# -5.45 kN/m#

weff +0.85 kN/m/m# +0.85 kN/m/m#

R* +4.25 kN/m# +4.25 kN/m##Loads/Design action effects per metre load width

Whangarei Dry Mill – Portal Frame Design

• Points of contraflexure define component length & splice locations

• Sections developed relative to suitability to resist required design actions– Bending, Axial and Shear forces– Relative stiffness controls moment distribution

Whangarei Dry Mill – Portal Frame Design

• Reduced rigidity draws less moment to sections • Ease of in-situ splice with box sections• Ease of fabrication• Section kept to depth to breadth ratio of 10 • Flybraces provide lateral restraint

Solid 1050x105 LVL section chosen for lower moment region

Whangarei Dry Mill – Portal Frame Design

Box sections chosen for higher moment regions• Hollow section optimises material usage• Provide increased lateral stability• Webs protrude for ease of splicing• Remnant from R2 used as flange

Whangarei Dry Mill – Box Beam Design

Critical Design Actions – R3

Load Case

M*kNm

N*c

kNN*t

kNV*kN

1.35G -259.0 34.9 46.7

0.9G+Wu 541.0 -114.0 100.0

1.2G+Wu -589.0 103.0 122.0Note: Flybraces at purlins both sides of C4

Design Action

Lay

mmLax

mm

Bending (+ve)

1600

Bending (-ve)

7020

Compression

1600 24750

Whangarei Dry Mill - Splice Design

Critical Design Action Effect – 1.2G+1.5Q (over 200 m2 area)M*=150.0 kNm N*c=56.6 kN V*=51.9 kN

Whangarei Dry Mill – Practical considerationUse full width of billet:

• Remnant from 1050x105 solid rafter used as flanges in box beams

• Remnant from 1050x42 2 x-band webs used as side wall girts

Design and detailing – general tips

Some important considerations in design/detailing:• For webs and slender sections use x-banded LVL• Use billet multiples and standard sections where

applicable• Always include fastener spacing and length• Detail components to be fixed during fabrication• Seal/paint all primary/main frame members to limit

moisture uptake• Any lamination of components should include a glue

‘sealant’ to prevent moisture ingress• Spray paint nail patterns on members in the factory• Pre-drill holes where applicable

Design and detailing – general tips

Some important considerations in design/detailing:• Any factory fitted gusset connections to be glue

nailed • If using bay lifts, consider stresses applied during

construction at joints• Always include bracketry under supply of fabrication

contract• Detail brackets to allow for timber tolerances• Use proprietary brackets where applicable • Always add moisture barriers to column/mullion base

connections• Box sections can limit the surfaces available to the

effects of fire • Use an experienced fabricator

Multi-storey building framing

Merritt Building

Merritt Building

Blockhouse Bay Indoor Tennis Centre

MOTAT Aviation Hall

MOTAT Aviation Hall

Diocesan School Pool

hySPAN portal frame in QLD, Australia

McCormick Centre for the Environment – Renmark, SA

Doweled moment joints with steel fin plates

32 m clear span Composting facility, 10 m bays

Mt Eden Normal School – TCC Floors

Mt Eden Normal School – TCC Floors

Thank you

Contact: CHH Woodproducts enquiriesaus@chhwoodproducts.com.au

Web: www.chhwoodproducts.com.auwww.chhsoftware.com

Phone: 1800 808 131