A Study of Semi­ridged and Non­Linear Behaviour of Nailed Joints in Timber Portal Frames

SYNOPSIS In this paper a study is made of the semi-rigid and non-linear behaviour of nailed knee joints in timber frames. A numerical analysis is applied to the non-linear deformation of the joints. The solution is derived using the stiffness method of analysis in which the rotation of each nailed joint is modelled by a series of piece-wise linear relationships, based on the load-deformation characteristics of nailed joints laterally loaded in single shear. The stiffness matrix is corrected at each step, to allow for joint flexibility; and the short-term non-linear deformation of frames, up to ultimate load, is calculated. Experimental verification is made using knee joint specimens and 6 m span timber portals with nailed plywood knee joints. The test results confirm the applicability of the analysis

Influence of test procedure on timber wall racking performance.

In the UK, the design procedure for calculating the racking strength of timber-framed walls is based on the rules in Eurocode 5 and given in PD 6693-1. Currently, the PD method does not include a procedure for calculating racking strength using the results from wall panel racking tests to BS EN 594. Under the Building Regulations (England and Wales), BS 5268-6.1:1996, which was superseded by Eurocode 5, can still be used and this standard includes a calculation method using test results from BS EN 594:1996. As BS EN 594:2011 uses a revised test procedure, it has been found that the results are no longer compatible with the BS 5268-6.1 design procedure. This paper describes an extensive experimental programme investigating the compatibility and suitability of the test method in BS EN 594:2011 with the racking design method in BS 5268-6.1:1996. The test results have been analysed and compared, and appropriate recommendations are made

Structural timber design.

Structural Timber Design is a comprehensive textbook that provides students of building and civil engineering courses with a wealth of information and in–depth guidance on design methods to the recently revised BS 5268 : Part 2 and the proposed Eurocode 5. It is also an invaluable reference source and design aid for practising engineers and architects. The text provides a step–by–step approach to the design of all the most commonly used timber elements and connections (illustrated by detailed work examples), and encourages the use of computers to carry out design calculations. I t covers the characteristics of timber; a review of BS 5268: Part 2 and its requirements; the design of beams and columns of solid, glued laminated and composite sections and mechanical and glued timber connections. The book also reviews the proposed Eurocode 5 and its limit states requirements, including the design of flexural and axially loaded members and connections

Performance of structural insulated panels

Structural insulated panels (SIPs) are gradually gaining popularity as an alternative construction material for residential and light commercial buildings in the UK. They show marked advantages in strength, thermal performance and speed of installation when compared with the traditional timber frame method of construction. While many types of composite panel building systems have been developed, panels made from a thick layer of foam (often expanded polystyrene) sandwiched between two layers of oriented strand board (OSB) or plywood are usually referred to as SIPs. They were developed in North America and although they have experienced wide-scale utilisation around the world, the concept is still relatively unknown in the UK. This paper details part of a comprehensive research study on SIPs at Napier University and deals with their performance under combined bending and axial compression and the effects of medium-term loading on panel integrity for use as load-bearing walls and columns. The results have illustrated that SIPs perform as an effective composite material possessing considerable strength and stiffness necessary to sustain required design loads

Structural timber design.

Structural Timber Design is a comprehensive textbook that provides students of building and civil engineering courses with a wealth of information and in–depth guidance on design methods to the recently revised BS 5268 : Part 2 and the proposed Eurocode 5. It is also an invaluable reference source and design aid for practising engineers and architects. The text provides a step–by–step approach to the design of all the most commonly used timber elements and connections (illustrated by detailed work examples), and encourages the use of computers to carry out design calculations. I t covers the characteristics of timber; a review of BS 5268: Part 2 and its requirements; the design of beams and columns of solid, glued laminated and composite sections and mechanical and glued timber connections. The book also reviews the proposed Eurocode 5 and its limit states requirements, including the design of flexural and axially loaded members and connections

Permeability of stressed concrete: Steady‐state method of measuring permeability of hardened concrete studies in relation to the change in structure of concrete under various short‐term stress levels

Abdy Kermani of the Structural Research Group at the Department of Civil Engineering, Napier Polytechnic of Edinburgh, found that permeability increases with increase in applied stress level depending on the type of the mix and the magnitude of the applied pressure. He also found that additives, which affect the composition, strength and propagation of micro cracks in concrete, can also have a significant influence on permeability

A Study of Semi-Rigid and Nonlinear Behaviour Of Nailed Joints in Timber Portal Frames

In this paper a study is made of the semi-rigid and non-linear behaviour of nailed knee joints in timber frames. A numerical analysis is applied to the non-linear deformation of the joints. The solution is derived using the stiffness method of analysis in which the rotation of each nailed joint is modelled by a series of piece-wise linear relationships, based on the load-deformation characteristics of nailed joints laterally loaded in single shear. The stiffness matrix is corrected at each step, to allow for joint flexibility; and the short-term non-linear deformation of frames, up to ultimate load, is calculated. Experimental verification is made using knee joint specimens and 6 m span timber portals with nailed plywood knee joints. The test results confirm the applicability of the analysis

EC5 - Deformation and creep of timber structures

With timber or wood-based structures, deformation rather than strength behaviour will commonly be the limiting factor in design and as such, a lack of understanding of design requirements may lead to under or over-designed timber members and connections. BS EN 1995-1-1:2004 is the Eurocode dealing with the design rules for buildings supported by timber structures, but the requirements for deriving structural deformations at different limit states are not always clearly presented or indeed defined. This paper aims to give guidance to the users of the Eurocode on the determination of instantaneous and creep deformations at the serviceability limit states and proposes a method for deriving deformations at the ultimate limit states, should this be required

Racking Performance of Structural Insulated Panels

Formed from a thick layer of polystyrene foam sandwiched between two layers of oriented strand board, structural insulated panels (SIPs) are a viable alternative to traditional wood stud shear walls. Developed in North America, SIPs satisfy building performance criteria while being both sustainable and cost effective. This paper details a comprehensive experimental and parametric study at Napier University examining the structural performance of shear walls constructed of SIPs under the action of both racking loads and combined bending and axial compression. The effects of size and position of openings, for doors and windows, were examined and compared to designs carried out in accordance with BS 5268 and Eurocode 5. The study has demonstrated that SIPs perform as an effective composite material possessing the strength and stiffness necessary to sustain required design loads