Collaborative Research: Nano-Engineered Superwood for Resilient Foundation Systems

木桩是一种可再生和低成本的基础系统。随着钢桩和混凝土桩的发展，木桩的使用稳步下降，因为木桩的刚度和强度较低，限制了其在轻载结构中的应用。该项目旨在为重载和弹性民用基础设施开发一种高刚度和强度、耐用且具有成本效益的超级木桩基础系统。最近对木材基纳米材料的研究已经产生了一种被称为超级木材的高性能结构材料，这对于民用，汽车，航空航天和制造工程领域的高级应用是理想的。这项研究将使用实验和建模技术和生命周期分析，通过岩土工程和木材复合材料工程研究人员之间的合作，设计和验证超级木桩基础系统。研究团队将通过现有的路易斯安那州立大学（LSU）外展计划，吸引代表性不足的少数族裔初中和高中学生参与地基和木材复合材料工程的研究。该项目还将为路易斯安那州立大学本科生和研究生的培训和教育做出贡献。Superwood是一种致密木材材料，通过对天然木材进行部分脱木质素，然后通过热压进行致密化。超级木材生产具有潜在的可持续性和成本效益，因为它避免了与波特兰水泥和钢铁相关的能源密集型制造过程。超级木材的强度和弹性模量不仅上级于天然木材，而且可能超过混凝土。超级木材还具有出色的耐久性，防止潮湿引起的腐烂和昆虫，如白蚁，强度降低最小。超级木材的显著特性预计将使超级木材桩能够（1）减轻当前木材桩的缺点（例如，结构承载力低，在硬打桩过程中易受损坏，易腐烂）和（2）在使用和强度极限状态下超过木材和混凝土桩的性能。本研究的目的是：（1）优化超级木桩的生产工艺条件，以提高超级木桩的力学性能和耐久性能，包括抗腐性和抗白蚁性;（2）通过室内试验研究超级木桩的土-桩相互作用行为;（3）建立数值模型，以预测超级木桩在不同土壤和荷载条件下的响应，及（4）透过生命周期分析，评估超级木桩的成本及环境影响。这项研究将促进超级木材在岩土工程中的进一步发展，包括地面改善，挡土墙和开挖结构的支撑。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

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.