School of Planning Architecture and Civil Engineering
David Keir Building, Stranmillis Rd, BT9 5AG, Belfast
Room OG 312.A
Tel (+44) (0) 28 9097 4027
MEng Civil Engineering, Queen’s University Belfast, Graduated June 2012
ICE QUEST Undergraduate Scholarship - 2008
Glued-in Rod Moment Connections in Low-Grade Timber
PhD project Description
Glued-in rods present a sustainable, aesthetically pleasing alternative to the cumbersome conventional steel moment connections that are often encountered in timber construction. The majority of research done in this area to date comprises steel rods glued-in to glued laminated (glulam) elements with lamellae of a high strength class timber. This research will investigate the use of locally sourced Irish Sitka Spruce which has a fast growth time but relatively poor strength and is of a low classification, typically C16. However, low transportation costs relative to imported timber means that Irish Sitka Spruce can be a very cost-effective building material if its full potential is utilised.
As well as alternative timber types, rod materials other than steel are being investigated, namely Fibre Reinforced Polymers (FRPs). FRPs are composite materials made of a polymer matrix reinforced with different fibres. They are more corrosion-resistant than steel and so they will have a longer service life, with less maintenance and monitoring required. Even the weakest FRP is stronger in tension than steel and they are all much lighter, meaning that an equally strong joint can be formed with less material required. Despite its significant cost effectiveness compared to CFRP and its greater tensile strength compared to GFRP, BFRP has only been touched upon in the literature. BFRP has a Young’s modulus closer to timber than steel and the aforementioned FRPs. It is also a much lower cost material compared to the other FRPs. These advantages coupled with limited current application have resulted in BFRP being selected for use in this research.
Glued-in rods have great potential in a wide range of both new build and restoration projects. Successful renovation has been carried out in roof and floor beams in buildings subject to decay. With regards to new build, five areas have been identified where glued-in rods may be used for connections: frame corner, beam-post connection, beam-beam joint, supports and hinged joints. The eventual application of the glued-in rods studied in this research is a frame corner in a Portal Frame system.
Dr Danny McPolin - Prof. Su Taylor
R. Steiger, E. Serrano, M. Stepinac, V. Rajcic, C. O’Neill, D. McPolin, R. Widmann, Strengthening of timber structures with glued-in rods, Construction and Building Materials, Available online 20 April 2015, ISSN 0950-0618, http://dx.doi.org/10.1016/j.conbuildmat.2015.03.097
Finalist: IStructE Young Researchers’ Conference, Poster Competition, 14th April 2014, IStructE Headquarters, London, UK
CERAI 2014. “Influence of embedded length of BFRP rods bonded parallel to the grain of low grade timber by pullout-bending tests”, O’Neill, C., McPolin, D., Taylor, S.E., and Harte, A.; 28-29 August 2014, Belfast
CERAI 2014. “Irish Timber – Characterisation, Potential and Innovation”, Harte, A., McPolin, D., Sikora, K., O'Neill, C. and O'Ceallaigh, C.; 28-29 August 2014, Belfast
COST FP1004 Early Stage Researcher conference, May 2014, Prague, Czech Republic
COST FP1101. Presentation on initial outline of project at working group meeting, September 2013, Trento, Italy
Timber; Composites; Glued-in rods (GiR), Timber repair, Timber connections