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Laurie J Cookson - One of the best experts on this subject based on the ideXlab platform.
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A Model for Timber Piles Attacked by Marine Borers
2020Co-Authors: Minh Ngoc Nguyen, Robert H Leicester, Laurie J Cookson, Gf FolienteAbstract:Durability is one of the most important considerations in the use of timber in construction. About 10 years ago, the Forestry and Wood Products Research and Development Corporation (FWPRDC) of Australia initiated a major national project on the design for durability of timber structures. The intention was to develop procedures for assessing the durability of all types of timber construction located anywhere in Australia. A major part of this project was to develop prediction models for the attack of timber by decay fungi, termites, corrosion (for fasteners) and Marine Borers. A project overview has been presented by Foliente et al. (2002). This paper describes the development of the model to predict the strength and service life of timber piles in Marine structures subjected to Marine Borer attack. The base model was primarily developed based on expert pinions and data obtained from extensive tests of nearly 700 small clear specimens of 25 hardwood species and CCA treated pine with 2 levels of preservative. The model was then fully developed so that it can be applied to all coastal zones in Australia, to numerous timber species used in practice, and also to other kinds of treated timber, e.g. creosote-treated timber and double-treated timber, i.e. the timber treated by both CCA and creosote. Reality checks of the model were then carried out with in-service assessment data of some 4500 Marine piles in Australia. Implementations of the model are then addressed and an example is provided.
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Service Life Design for Timber Piles Attacked by Marine Borers
Australian Journal of Structural Engineering, 2015Co-Authors: Minh Ngoc Nguyen, Chihsiang Wang, Laurie J Cookson, Robert H LeicesterAbstract:This paper presents a proposed procedure for the design of timber piles or posts used in Marine structures subjected to Marine Borer attack. It is assumed that the most severe Borer attack, regardless of Borer species, can be represented by a narrow front along the perimeter of the timber pile cross-section within the tidal zone. The parameters chosen for engineering design relate to timber properties, environment parameters and structural configurations. For practical purposes, untreated timber species are grouped into four Marine durability classes, and treated timber sapwood is classified according to the preservative retention. The environment effects are considered in terms of seven coastal zones and three salinity classes of seawater. Using the proposed procedure, the design attack depth and hence the loss of cross-section can be computed, from which the load capacity can be evaluated for a design service life.
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probabilistic procedure for design of untreated timber piles under Marine Borer attack
Reliability Engineering & System Safety, 2008Co-Authors: Minh Ngoc Nguyen, Robert H Leicester, Chihsiang Wang, Laurie J CooksonAbstract:This paper presents a probabilistic design procedure for untreated timber piles under attack of Marine Borers, in which a new probabilistic-based durability factor is derived and introduced into the current Australian engineering design procedure. In evaluating this durability factor, a prediction model of Marine Borer attack on timber piles, which was developed in a national project in Australia is used for modeling the attack progress. Examples of the durability factor computed for untreated timber piles with different diameters or located at different coastal zones are provided.
Simon M. Cragg - One of the best experts on this subject based on the ideXlab platform.
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laboratory screening of thermo mechanically densified and thermally modified timbers for resistance to the Marine Borer limnoria quadripunctata
European Journal of Wood and Wood Products, 2018Co-Authors: Malte Janus, Simon M. Cragg, Christian Brischke, Linda Meyerveltrup, Jorg WehsenerAbstract:Thermo-mechanically densified material of five different wood species (English oak, European ash, European beech, Norway spruce, poplar) was subjected to three different vacuum-heat treatment processes (A 230 °C/20% vacuum; B 230 °C/80% vacuum; C 240 °C/20% vacuum) and tested for its resistance against the Marine Borer Limnoria quadripunctata by comparing their faecal pellet production rates. The three different treatments caused a notable reduction in the feeding rates of up to 66% indicating significantly increased durability against Limnoria if exposed to Marine environment. Neither the treatment temperature nor the application of a higher vacuum affected the faecal pellet production significantly.
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Evaluating the potential of lesser used timber species for Marine construction
2016Co-Authors: John R. Williams, Gervais S. Sawyer, Simon M. Cragg, John Icely, Jonathan Simm, Melanie Meaden, Luisa M. S. BorgesAbstract:Naturally durable species of timber are used as an alternative to preservative-treated timber for Marine structures, but many species have not been evaluated for their potential for use in this environment. EN 275 evaluates Marine Borer resistance and specifies a 5-year test period: too long a period for screening tests to be economically viable. Furthermore, the test does not evaluate abrasion resistance. Novel fast-track screening methods were employed in this study to evaluate the Marine Borer and abrasion resistance of eighteen lesser used timber species. Comparative resistance was assessed by comparing the feeding rates of Marine Borers and abrasion resistance observed in candidate species against greenheart and ekki which were used as benchmark species. A number of lesser used species, originating from South America and West Africa, performed better than the benchmark species in laboratory tests and over an eighteen month exposure period in the sea. A number of species also performed comparatively well in abrasion trials although resistance to abrasion does not necessarily correlate with resistance to attack by Marine Borers.
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Resistance of modified wood to Marine Borers
International Biodeterioration & Biodegradation, 2015Co-Authors: André Klüppel, Simon M. Cragg, Holger MilitzAbstract:Abstract The resistance of differently modified wood to the common shipworm, Teredo navalis , and the wood boring crustacean, Limnoria quadripunctata , was assessed in a field trial and by means of a short term laboratory assay, respectively. Scots pine ( Pinus sylvestris ) sapwood was treated with TEOS (tetra-ethoxy-ortho-silane) and different thermosetting resins, namely phenol formaldehyde (PF) and methylated melamine formaldehyde (MMF). Additionally, acetylated and untreated Radiata pine ( Pinus radiata ) was included. In the field trial according to EN 275 in the Baltic Sea over a period of six years the specimens were exclusively attacked by T . navalis . For the laboratory assay, matchstick-sized samples cut from spare panels prepared for the field trial were subjected to individuals of L . quadripunctata ; faecal pellet production served as a measure of feeding rate. Treatments that prevented shipworm attack in the field also reduced feeding of L . quadripunctata in the laboratory assay: efficacy of resin treatments was enhanced by parameters that increase the amount of resin in the cell wall (i.e. high WPG and dry curing conditions); acetylation resulted in high resistance; and TEOS treatment was not effective. The results suggest that modification on cell wall level is required to impart Marine Borer resistance.
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laboratory screening of tropical hardwoods for natural resistance to the Marine Borer limnoria quadripunctata the role of leachable and non leachable factors
Holzforschung, 2008Co-Authors: Luisa M. S. Borges, Simon M. Cragg, Julien Bergot, John Williams, Ben Shayler, Gervais SawyerAbstract:The Marine Borer Limnoria ingests essential wood components including the extractives the wood contains. Some extractives may confer Borer resistance on certain timbers. Feeding by Limnoria correlates with the rate of production of faecal pellets. The faecal pellet production rate and mortality on over 40 test timbers and non-resistant Pinus sylvestris sapwood was measured over 15 days. By placing animals in leachate from wood and with wood in flowing seawater, the effects of leachingresistant and water-soluble compounds were measured. Some previously untested timbers affected Limnoria as strongly as timbers reputed for durability in Marine construction. Wood of Minquartia guianensis, Nectandra rubra and Bruguiera gymnorhiza caused high mortality, and pellet production on them was less than 10% of production on P. sylvestris. Suppressed feeding rates, but with no heavy mortality, were observed on known durable species such as Chlorocardium rodiei, Dicorynia guianensis, Lophira alata and Nauclea trillesii, but also on Cynometra ananta, Distemonanthus benthamianus, Enterolobium schomburgkii, Goupia glabra, Hymenaea courabil, Mammea africana, Shorea sp. and Sacoglottis guianensis. Leachate from B. gymnorhiza, G. glabra, H. coubaril, N. rubra and Shorea sp. caused high mortality. These short-term bioassays thus detected clear differences between wood species in their resistance to Limnoria that matched findings from long-term Marine trials, while indicating new species worthy of detailed testing.
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contribution of hardness to the natural resistance of a range of wood species to attack by the Marine Borer limnoria
Holzforschung, 2007Co-Authors: Simon M. Cragg, Cedric Danjon, Hugh MansfieldwilliamsAbstract:This study set out to determine whether wood surface hardness plays a role in determining the resistance to Limnoria attack. The feeding rates of the wood-boring crustacean Limnoria quadripunctata on matchstick-sized samples of a range of timbers were assessed by measuring the production of faecal pellets under forced feeding conditions. Pellet production rates varied significantly between wood species, with production on Lophira alata (ekki) 25-fold lower than that on non-durable Scots pine (Pinus sylvestris) sapwood. The surface hardness of the timbers was measured for air-dry and seawater-soaked samples using a microindentation technique. The force required for a universal testing machine to drive a 150-μm-diameter pin 1.2 mm into the samples was measured. For all wood species, the hardness of seawater-soaked wood was lower than that of air-dry wood. Hardness was found to correlate positively with density. Pellet production rates showed a significant negative correlation with hardness across the range of species used, but if the denser species alone were considered, wood species significantly affected the rate, but hardness did not. In view of these observations, tests on resistance to attack by Limnoria should include a denser, non-durable wood species for comparison, as its hardness would likely be more similar to that of the durable species.
Minh Ngoc Nguyen - One of the best experts on this subject based on the ideXlab platform.
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A Model for Timber Piles Attacked by Marine Borers
2020Co-Authors: Minh Ngoc Nguyen, Robert H Leicester, Laurie J Cookson, Gf FolienteAbstract:Durability is one of the most important considerations in the use of timber in construction. About 10 years ago, the Forestry and Wood Products Research and Development Corporation (FWPRDC) of Australia initiated a major national project on the design for durability of timber structures. The intention was to develop procedures for assessing the durability of all types of timber construction located anywhere in Australia. A major part of this project was to develop prediction models for the attack of timber by decay fungi, termites, corrosion (for fasteners) and Marine Borers. A project overview has been presented by Foliente et al. (2002). This paper describes the development of the model to predict the strength and service life of timber piles in Marine structures subjected to Marine Borer attack. The base model was primarily developed based on expert pinions and data obtained from extensive tests of nearly 700 small clear specimens of 25 hardwood species and CCA treated pine with 2 levels of preservative. The model was then fully developed so that it can be applied to all coastal zones in Australia, to numerous timber species used in practice, and also to other kinds of treated timber, e.g. creosote-treated timber and double-treated timber, i.e. the timber treated by both CCA and creosote. Reality checks of the model were then carried out with in-service assessment data of some 4500 Marine piles in Australia. Implementations of the model are then addressed and an example is provided.
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Service Life Design for Timber Piles Attacked by Marine Borers
Australian Journal of Structural Engineering, 2015Co-Authors: Minh Ngoc Nguyen, Chihsiang Wang, Laurie J Cookson, Robert H LeicesterAbstract:This paper presents a proposed procedure for the design of timber piles or posts used in Marine structures subjected to Marine Borer attack. It is assumed that the most severe Borer attack, regardless of Borer species, can be represented by a narrow front along the perimeter of the timber pile cross-section within the tidal zone. The parameters chosen for engineering design relate to timber properties, environment parameters and structural configurations. For practical purposes, untreated timber species are grouped into four Marine durability classes, and treated timber sapwood is classified according to the preservative retention. The environment effects are considered in terms of seven coastal zones and three salinity classes of seawater. Using the proposed procedure, the design attack depth and hence the loss of cross-section can be computed, from which the load capacity can be evaluated for a design service life.
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probabilistic procedure for design of untreated timber piles under Marine Borer attack
Reliability Engineering & System Safety, 2008Co-Authors: Minh Ngoc Nguyen, Robert H Leicester, Chihsiang Wang, Laurie J CooksonAbstract:This paper presents a probabilistic design procedure for untreated timber piles under attack of Marine Borers, in which a new probabilistic-based durability factor is derived and introduced into the current Australian engineering design procedure. In evaluating this durability factor, a prediction model of Marine Borer attack on timber piles, which was developed in a national project in Australia is used for modeling the attack progress. Examples of the durability factor computed for untreated timber piles with different diameters or located at different coastal zones are provided.
A G Gopalakrishna Pillai - One of the best experts on this subject based on the ideXlab platform.
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Resistance of preservative treated rubber wood (Hevea brasiliensis) to Marine Borers
Holz als Roh- und Werkstoff, 2004Co-Authors: Leela Edwin, A G Gopalakrishna PillaiAbstract:Die Anfälligkeit von Gummibaumholz gegen den Angriff von Bohrmuscheln begrenzt seine Verwendung für die Seefahrt. In dieser Studie werden drei Typen von Bioziden ausgewählt, nämlich Kupfer-Kreosot, Arsen-Kreosot und eine zweifache Schutzbehandlung mit Kupfer-Chrom-Arsen und Kreosot. Die entsprechenden Schutzwirkungen gegen biologischen Abbau wurden ermittelt und verglichen. Die behandelten Platten wurden im Hafen von Conchin zur Prüfung ausgesetzt. Das Ausmaß der Schädigung durch Bohrmuscheln wurde visuell, mittels Röntgenaufnahmen sowie durch Prüfen der mechanischen Festigkeit bestimmt. Die unbehandelten Proben waren innerhalb von sechs Monaten zerstört, während die Schutzbehandlung den biologischen Abbau im Meer verhinderte. Das wurde bestätigt durch radiographische Untersuchungen und Drucktests bei maximaler Last. Die Lebensdauer dieses billigen und leicht erhältlichen Schnittholzes kann soweit erhöht werden, dass die Anforderungen des kleinen Wirtschaftssektors der Fischerei erfüllt werden. The susceptibility of rubber ( Hevea brasiliensis ) wood to Marine Borer attack limits its use for Marine purposes. In the present study three types of biocides viz. copper creosote, arsenical creosote and a dual preservative treatment with copper- chrome- arsenic and creosote were selected for comparing their relative efficacy in preventing biodeterioration. The treated panels were exposed at the test site in Cochin harbour. The extent of internal damage through Marine Borer attack was assessed through visual observations, X-ray photographs and mechanical strength testing. The untreated test panels were destroyed within six months whereas it was found that preservative treatment prevented biodeterioration under Marine conditions. This was confirmed by radiographic studies and comparison of compressive stress at maximum force. The service life of this cheaply and easily available timber can be increased to meet the growing demand of timber in the small-scale fisheries sector.
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Resistance of preservative treated rubber wood (Hevea brasiliensis) to Marine Borers
European Journal of Wood and Wood Products, 2004Co-Authors: Leela Edwin, A G Gopalakrishna PillaiAbstract:The susceptibility of rubber (Hevea brasiliensis) wood to Marine Borer attack limits its use for Marine purposes. In the present study three types of biocides viz. copper creosote, arsenical creosote and a dual preservative treatment with copper- chrome- arsenic and creosote were selected for comparing their relative efficacy in preventing biodeterioration. The treated panels were exposed at the test site in Cochin harbour. The extent of internal damage through Marine Borer attack was assessed through visual observations, X-ray photographs and mechanical strength testing. The untreated test panels were destroyed within six months whereas it was found that preservative treatment prevented biodeterioration under Marine conditions. This was confirmed by radiographic studies and comparison of compressive stress at maximum force. The service life of this cheaply and easily available timber can be increased to meet the growing demand of timber in the small-scale fisheries sector.
Robert H Leicester - One of the best experts on this subject based on the ideXlab platform.
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A Model for Timber Piles Attacked by Marine Borers
2020Co-Authors: Minh Ngoc Nguyen, Robert H Leicester, Laurie J Cookson, Gf FolienteAbstract:Durability is one of the most important considerations in the use of timber in construction. About 10 years ago, the Forestry and Wood Products Research and Development Corporation (FWPRDC) of Australia initiated a major national project on the design for durability of timber structures. The intention was to develop procedures for assessing the durability of all types of timber construction located anywhere in Australia. A major part of this project was to develop prediction models for the attack of timber by decay fungi, termites, corrosion (for fasteners) and Marine Borers. A project overview has been presented by Foliente et al. (2002). This paper describes the development of the model to predict the strength and service life of timber piles in Marine structures subjected to Marine Borer attack. The base model was primarily developed based on expert pinions and data obtained from extensive tests of nearly 700 small clear specimens of 25 hardwood species and CCA treated pine with 2 levels of preservative. The model was then fully developed so that it can be applied to all coastal zones in Australia, to numerous timber species used in practice, and also to other kinds of treated timber, e.g. creosote-treated timber and double-treated timber, i.e. the timber treated by both CCA and creosote. Reality checks of the model were then carried out with in-service assessment data of some 4500 Marine piles in Australia. Implementations of the model are then addressed and an example is provided.
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Service Life Design for Timber Piles Attacked by Marine Borers
Australian Journal of Structural Engineering, 2015Co-Authors: Minh Ngoc Nguyen, Chihsiang Wang, Laurie J Cookson, Robert H LeicesterAbstract:This paper presents a proposed procedure for the design of timber piles or posts used in Marine structures subjected to Marine Borer attack. It is assumed that the most severe Borer attack, regardless of Borer species, can be represented by a narrow front along the perimeter of the timber pile cross-section within the tidal zone. The parameters chosen for engineering design relate to timber properties, environment parameters and structural configurations. For practical purposes, untreated timber species are grouped into four Marine durability classes, and treated timber sapwood is classified according to the preservative retention. The environment effects are considered in terms of seven coastal zones and three salinity classes of seawater. Using the proposed procedure, the design attack depth and hence the loss of cross-section can be computed, from which the load capacity can be evaluated for a design service life.
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probabilistic procedure for design of untreated timber piles under Marine Borer attack
Reliability Engineering & System Safety, 2008Co-Authors: Minh Ngoc Nguyen, Robert H Leicester, Chihsiang Wang, Laurie J CooksonAbstract:This paper presents a probabilistic design procedure for untreated timber piles under attack of Marine Borers, in which a new probabilistic-based durability factor is derived and introduced into the current Australian engineering design procedure. In evaluating this durability factor, a prediction model of Marine Borer attack on timber piles, which was developed in a national project in Australia is used for modeling the attack progress. Examples of the durability factor computed for untreated timber piles with different diameters or located at different coastal zones are provided.