Full Session with Abstracts
Among the four major structural materials, steel, concrete, and masonry have well-established and detailed standards of practice. In contrast, existing standards for wood are mostly product-specific and aimed at manufacturing tolerances and methods. There is no single national standard for quality control of fabrication, workmanship and quality assurance in construction for wood construction in the U.S. despite being by far the most commonly used structural material. Consequently, the precision of wood construction and quality of wood structures are perceived as being lower than those of steel, concrete, and masonry structures. Forensic studies conducted on wood structures further substantiates this perception, more often pointing to poor construction execution or material specification in lieu of a flawed design. Given the vast inventory of wood buildings in the U.S., improving construction practices and longevity for such structures would have significant impact on the sustainability and quality of the United States building infrastructure.
This paper is part of a SEI-funded special project awarded to the SEI Performance of Wood Structures Committee to lead towards the development of a standard of practice for the performance of wood structures. Focus is placed in this paper on the role of damage mechanisms caused by decay fungi, an issue typically not encountered outside of wood construction. This paper reviews the state of the art in research on proliferation rates of common fungal species in the U.S., and patterns of losses in material mechanical properties and subsequent structural performance.
The state of current practices regarding the biodeterioration of structural wood by decay fungi is also assessed, including: (1) the initial identification of deterioration, or conditions of high risk for deterioration, (2) the determination of the severity of deterioration, and (3) measures taken to mitigate initial or further damages to wood members. Case studies regarding biological deterioration are discussed to highlight these processes. Leveraging findings from research, practice, and the case studies, preliminary recommendations are offered for adoption into a standard of practice for wood structures for design, construction, and service. Alongside an overall improvement of wood construction quality, this standard is intended to uphold an extension of building life while minimizing lifetime maintenance costs and potential downtime.