Your search resulted in 17 documents.
Some experiences with attack of microorganisms on wooden constructions supporting foundations of houses and bridges
1997 - IRG/WP 97-10232
Reconstructions of bridges and public buildings or damage of houses during the construction of subway lines in Berlin have led to a number of inspections of wooden foundations, mostly pine or spruce piles, representing service lives of between ca. 70 and 140 years. In all cases bacterial attack was found both in wood submerged in ground water and in surface water. The extent of deterioration diffe...
M Grinda
Severe decay damages of bridges made of ekki (Lophira alata) wood known as a durable species
2000 - IRG/WP 00-10383
Bridges made of ekki (azobe, bongossi, Lophira alata Banks et Gaertn.) timbers were severely decayed only 10 years after the construction possibly caused from no maintenance for the periods. The reason of no maintenance is due to the misunderstandings on wood durability against wood-decaying fungi. Some civil-engineers and architectures understand "durable species" means "absolutely decay-durable ...
S Doi, T Sasaki, Y Iijima
Recent development in North American industrial wood preservation plants
1988 - IRG/WP 3467
After remaining static for many years there have been a number of changes in plant design and treating cycles in recent years. This has been particularly true in the USA where few restrictions are placed on plant treating cycles by specifications; since only results type specifications are used. It is also important to realize that the AWPA Specifications for Southern Yellow Pine only call for tre...
J F Bridges
Monitoring a Timber Bridge in Norway
2004 - IRG/WP 04-40282
We have instrumented three different timber bridges in Norway for the Norwegian Public Roads Administration. The goal was to learn more about the properties of timber bridges. We have instrumented Evenstad Bridge, Daleråsen Bridge and the last year Flisa Bridge. All bridges are have creosoted glulam trusses and creosoted stress laminated deck. Evenstad and Flisa have an asphalt deck on top, while...
F G Evans
Quasi-in-situ durability tests on oak timber bridges
2013 - IRG/WP 13-20510
This study aims on developing a method for determination of wood durability on samples taken from real structures in service. Therefore quasi-in-situ durability tests have been conducted exemplarily on timber bridges made from English oak (Quercus robur L.). Drilling cores were found to be a feasible alternative to standard specimens for laboratory durability tests against pure cultures of Basidio...
C Brischke, C J Behnen, M-T Lenz, K Brandt, E Melcher
Durability and Wood Protection for Historic Covered Bridges in the United States
2014 - IRG/WP 14-10829
A majority of the covered wooden bridges in United States were built in the mid -1800’s. These structures represent a unique cultural and technological heritage from that era. Over time, these bridges have been deteriorated by microorganisms and insects or damaged by acts of vandalism and arson. The National Historic Covered Bridge Preservation (NHCBP) Program sponsored by the Federal Highway Ad...
V W Yang, C A Clausen
Laboratory investigation of fire protection coatings for creosote-treated timber railroad bridges
2014 - IRG/WP 14-30639
As the incidence of timber railroad bridge fires increases, so has the need to develop protective measures to reduce the risk from accidental ignitions primarily caused by hot metal objects. Of the six barrier treatments evaluated in the laboratory for their ability to protect timbers from fires sourced with ignition from hot metal objects only one intumescent coating provided adequate fire prote...
C A Clausen, R H White, J P Wacker, S T Lebow, M A Dietenberger, S L Zelinka, N M Stark
CreoSub – New protection technology to substitute creosote in railway sleepers, timber bridges, and utility poles
2014 - IRG/WP 14-30644
Creosote oil is one of the oldest industrially used wood preservatives. Due to its toxic profile, the European Commission has restricted the use of creosote specific applications, but it is highly controversial within the European Commission. Its approval for use after 2018 is very questionable and may depend on derived research results until then, i.e., the viability of alternatives developed to ...
U Hundhausen, K-C Mahnert, A Gellerich, H Militz
Creosote leaching from timber bridges in Norway – a practical classification approach
2016 - IRG/WP 16-40744
Creosote is widely used as a wood preservative for highway timber bridges in Norway. However, excessive creosote leaching at various highway timber bridge sites leads to a bad reputation for the use of creosote treated timber constructions and the use of wood in general. Macro- and micro anatomical factors such as amount of heartwood, annual ring width, annual ring orientation, ray- height and com...
A Treu, K Zimmer
Comparative Durability of Timber Bridges in the USA
2017 - IRG/WP 17-20615
As engineers begin to utilize life-cycle-cost design approaches for timber bridges, there is a necessity for more reliable data about their durability and expected service life. This paper summarizes a comprehensive effort to assess the current condition of more than one hundred timber highway bridge superstructures throughout the United States. This national study was jointly administered by the ...
J P Wacker, B K Brashaw
Evaluation of timber bridges with special consideration of detail design
2017 - IRG/WP 17-40781
Since 1997 the use of wood in bridge construction has been increasingly criticized by the Hamburg federal state authority supposedly because of shortened service life due to decay. With regard to wood research, however, it is often suggested that use of timber is suitable for weathered structures as long as constructive protection measures will be observed. In order to unravel the reasons for the ...
K Robbers, J Fromm, E Melcher
Prefacricated modular wooden bridges
2017 - IRG/WP 17-40785
The bridge consists of simple, identical pre-fabricated triangular wooden panels joined top and bottom to make up trusses. These trusses are in turn joined together side by side in pairs and are braced to one another to create a girder construction. The deck is carried on top of the trusses, an arrangement which has several advantages for such an uncomplicated structure. It is built up on site, af...
L Jayanetti
Solid Timber Bridges – Latest Developments
2017 - IRG/WP 17-40788
The technology of gluing in wood construction has evolved considerably in recent years. This has been shown especially in timber bridges that Glulam is now the main building material. A further development is the so-called block gluing, which provides a good basis for supporting structures. Numerous bridges, especially in central Europe, appeal by unique design and monolithic and solid construction. These structures base on two main developments: block lamination of glulam and the composite of timber and concrete to one structural system.
F Miebach
The potential and the challenges of acetylated wood in timber bridges - experiences from an ongoing project
2017 - IRG/WP 17-40792
Acetylated wood is known to be a durable and dimensional stable alternative for high performance materials, and has high potential for exterior timber structures. Research has shown that acetylated wood can be effectively bonded by various adhesive types. However, one of the most common used adhesives for timber constructions, Melamine Urea Formaldehyde (MUF), shows a high degree of delamination o...
A Treu, R Bredesen, F Bongers
Performance of Norway spruce bridge in North-West Spain after 12 years exposure
2017 - IRG/WP 17-40796
Across Europe is very common to find bridges build in sawn and glue-laminated wood. Most of these bridges used softwood wood species such as: fir, spruce, larch and pine.
In Spain wooden bridges, became more and more popular since nineties, when sawn and glue-laminated wood were utilized for building exterior wooden structures in overall Spain.
This material, sawn and glue-laminated wood, are ma...
D Lorenzo, J Fernández-Golfín, M Touza, M Guaita, A Lozano, J Benito
A summary of history and use of timber bridges in New Zealand
2017 - IRG/WP 17-40801
Wooden bridges have been an important part of road and rail networks in New Zealand. While wooden structures have largely been replaced by concrete and steel on major arteries they still have a place where lightweight, easily assembled structures are needed. These timber bridges may also be a cheaper alternative to other materials in roads which carry relatively low traffic loads. In the last ten ...
D Page, T Singh
Review on protection of timber bridges in Norway and other countries
2017 - IRG/WP 17-40809
Wood plays a major role in design and construction of modern bridges in Norway. Typical elements of those bridges are double impregnated glued laminated members, stress laminated timber decks, slotted-in steel plates, metal cladding of the surfaces of loadbearing members, and cross girders made of steel. Selected examples of timber bridges in Norway are presented. This review paper gives an overvi...
K-C Mahnert, U Hundhausen