Collaborative Research: Nano-Engineered Superwood for Resilient Foundation Systems

Louisiana State University Agricultural Center, Baton Rouge LA

Investigators

Abstract

Timber piles are a renewable and low-cost foundation system. With the development of steel and concrete piles, the use of timber piles has steadily declined as timber piles have low stiffness and strength, limiting their applications to lightly loaded structures. This project aims to develop a high stiffness and strength, durable, and cost-effective superwood pile foundation system for heavily loaded and resilient civil infrastructure. Recent research on wood-based nanomaterials has led to a high-performance structural material known as superwood, which is desirable for advanced applications in the fields of civil, automotive, aerospace, and manufacturing engineering. This research will use experimental and modeling techniques and life-cycle analysis to engineer and verify the superwood pile foundation system through collaboration between geotechnical and wood composite engineering researchers. The research team will engage underrepresented minority middle and high school students in research of foundation and wood composite engineering via existing Louisiana State University (LSU) outreach programs. The project will also contribute to the training and education of undergraduate and graduate students at LSU. Superwood is a densified wood material produced by partially delignifying natural wood and subsequent densification through hot-pressing. Superwood production is potentially sustainable and cost-effective as it avoids energy-intensive manufacturing processes associated with Portland cement and steel. The strength and elastic modulus of superwood are not only superior to those of natural wood, but could also exceed those of concrete. Superwood also has excellent durability against moisture-induced decay and insects such as termites with minimal strength reduction. The remarkable properties of superwood are expected to enable superwood piles to (1) mitigate the disadvantages of current timber piles (e.g., low structural capacity, vulnerability to damage during hard-driving, and susceptibility to decay) and (2) to exceed the performance of timber and concrete piles for both service and strength limit states. The objectives of this research are to (1) optimize processing conditions for producing superwood piles in relation to their mechanical properties and durability performance including decay and termite resistances, (2) investigate the soil-pile interaction behavior of superwood piles through laboratory experiments, (3) develop numerical models to predict the responses of superwood piles under different soil and loading conditions, and (4) assess the cost and environmental impacts of superwood piles by performing life-cycle analysis. This research will promote further development of superwood in geotechnical engineering, including ground improvements, retaining walls, and support of excavation structures. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.