Design
Load transfer errors from roof to ground at lintel & floor levels
Sometimes when transferring a load from one level to another in a timber frame, the vertical passage of the load is lost at a lower level.
Maintenance
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Safety
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Structural hardwood
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MGP pine
Availability of MGP pine
MGP pine is available in a range of standard sizes. This article gives the availability of these.
Properties of Machine Graded Pine
Most Radiata Pine sold in Australia for structural use is now machine graded into stress grades. This article lists the grades with their working stresses and other structural information.
Adhesives
Introduction to adhesives
Adhesives are substances which hold materials together by surface attachment.
Adhesive Classifications
The correct adhesive has to be used to achieve the required bond durability, longevity, strength and rigidity.
Construction Adhesives
Adhesives that are required to resist a significant loading are called structural adhesives.
Thermosetting Adhesives
Epoxy resins, casein and an extensive range of formaldehyde based products are all thermosetting adhesives.
Thermoplastic Adhesives
Thermoplastics soften as temperature is increased, so they tend to creep under load. The bond is considered non-durable when exposed to moisture.
Affect of timber species on adhesive bond
Several species-dependant characteristics of timber can affect the performance of adhesives.
Choice of adhesive
There are several factors to consider when selecting adhesives.
Factors Affecting the Adhesive Bond - Moisture Content
Timber moisture content is a critical factor in adhesive performance.
Factors Affecting the Adhesive Bond - Surface Quality and Treatments
Condition of the timber surface affects adhesion.
Factors Affecting the Adhesive Bond - Adhesive Spread
Insufficient adhesive results in bond failure due to lack of glue solids, while excess adhesive can cause low bond strength.
Factors Affecting the Adhesive Bond - Assembly Time
The time taken during gluing is crucial to the bond development.
Factors Affecting the Adhesive Bond - Formulation and Ambient Temperature
Ambient temperature affects the rate of cure and dry-out.
Factors Affecting the Adhesive Bond - Adhesive Mix
To obtain satisfactory adhesive performance, it is essential that the components be thoroughly mixed in the correct proportions.
Factors Affecting the Adhesive Bond - Pressure and Temperature
Pressure must be applied to bring the surfaces into intimate contact during bonding. The curing process is also dependent on temperature.
Glulam
Introduction to Glue Laminated Timber
Glue Laminated Timber, or glulam, is a structural material manufactured by gluing timber laminates together to produce large sizes and long lengths.
Manufacture and quality control of glue laminated timber
In order to produce laminated members longer than the original length of the laminates, the laminates must be end-jointed to make up the length of the final member.
Timber species for glue laminated timber
Glued laminated timber is available in a range of both hardwood and softwood species.
Shapes of Glue Laminated Timber
Glue laminated timber can be produced straight or curved. For most columns, straight timber is used. Camber is often built into beams to reduce the visual effect of deflection under load.
Fire Resistance of Glued Laminated Timber
Timber is classed as a "combustible" material in AS 1530 Part 1. However, it can be included as a fire rated component or structure using the process set out in AS1530 Part 4.
Strength and stiffness of glued laminated timber
The strength of laminated timber is more consistent than that of individually stress graded timber, as the distribution of strength reducing characteristics such as knots, splits, slope of grain and material density minimises strength deviation between laminated components.
Adhesives for Glue Laminated Timber
Structural glue laminated timber is made from three main types of adhesives.
Nail plated products
Nailplate Joined Structural Timber - Introduction and Product Types
Larger size and longer length timber products can be produced from short lengths of smaller sized timber by edge-jointing and butt-jointing using nailplates
Nailplate Joined Timber - Applications
Nailplate joined timber beams are "engineered" products. While some beams are designed for multiple uses, they are usually constructed for a particular application.
Nailplate Joined Timber – Structural Properties and Appearance
The allowable spans of nailplated joined beams are equivalent to those of solid timber in many cases. However the structural properties are different so a joined beam is not necessarily a substitute for solid timber.
Nailplate Joined Timber - Handling and Storage
Handling of joined beams requires care to ensure that nailplates are not damaged or dislodged.
Pre-Fabricated Trusses - Handling, Storage and Erection
Pre-fabricated trusses are easily damaged if handled carelessly in a horizontal position.
Pre-Fabricated Trusses - Introduction, Types and Applications
Pre-fabricated timber trusses consist of chords and webs, usually held together by toothed metal nailplates.
Pre-Fabricated Trusses - Specification
Several factors need to be included in the specification of trusses.
Wood panels
Reconstituted Wood Panels - Introduction
Reconstituted wood panels are products made from wood particles bonded together to produce a flat sheet.
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