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Bacterial Deteriorations of Wooden Pile Foundations due to Permanent Soil and Water Contact
Abstract:
Many structures resting on pile foundations, which are surrounded by water in the soil for decades or centuries. In the context of status explorations or assessments questions arise concerning their conservation status and their durability. The paper presents the results of extensive in situ studies and laboratory tests, which were performed on older wooden pile foundations of port facilities, bridges and building foundations in the framework of planning of maintenance measures. In the focus of this work are studies on the biotic attack to the woods and its effect on the density and strength characteristics of the piles. Inter alia, the investigations have revealed that the wood under the said anaerobic conditions suffers deterioration due to bacterial attack, rarely by higher fungi. As discovered by microscopic investigations on thin sections, the bacterial attack appears as a partial degradation in the individual wood cells, especially in the middle lamella of the late wood cells and the dots. As indicated by the results of the of the density and strength test results, the bacterial attack is - compared to fungal attack - a very slow but steady process. It causes also strength reduction of the woods and losses of the load bearing capacity of the structures, and has to be taken into account in the static assessments.
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Pages:
153-160
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Online since:
April 2014
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