Research
On-going thesis research investigating navigational complexity in structural design standards perceived by end-users.
What is 'complexity' and how can it be measured? Are smaller standards always preferred? What can we learn about the structure of and navigation through a standard by examining it's network of references?
This paper demonstrates the determination of bamboo joint properties by the process of complete joint testing as permitted and described in ISO 22156 §10.2. The moment resisting behaviour of a bolted fish mouth connection is selected to elaborate upon and demonstrate the entire process of complete joint testing on a simple connection type. The bolted fish mouth joint tested exhibited considerable variation of performance parameters resulting in relatively low characteristic design parameters of yield strength, ultimate strength and rotational stiffness.
Harries, K.A., Rogers, C.W., & Brancaccio, M. (2022) “Bamboo Joint Capacity Determined by ISO 22156 ‘Complete Joint Testing’ Provisions." Adv. in Bamboo Sci. (1). https://doi.org/10.1016/j.bamboo.2022.100003
Bamboo-reinforced concrete is an ill-advised concept. Despite this, many researchers continue to investigate the replacement of steel with bamboo as reinforcement in concrete flexural members. This study provides a side-by-side comparison of the flexural behaviour of plain unreinforced concrete, steel reinforced concrete and two variations of bamboo-reinforced concrete comparable to the steel reinforced beam tested. As expected, the bamboo-reinforced concrete performs marginally better than unreinforced concrete but is entirely unable to approach the performance of under-reinforced steel-reinforced concrete. This paper underscores the fact that bamboo-reinforced concrete is not only ill-advised, but may indeed be structurally dangerous.
Harries, K.A., Rogers, C., & Silva, E. (2022). "Experimental Demonstration of the Poor Structural Performance of Bamboo-Reinforced Concrete Flexural Members." 18th International Conference on Non-conventional Materials and Technologies (NOCMAT 2022). https://doi.org/10.5281/zenodo.6569781
This project investigated practical repair methods using high performance and traditional materials which can be applied to corroded and/or damaged steel girder ends in their in-situ state. Observed corrosion damage follows well known patterns: beam end corrosion is associated with leaking expansion joints and is most prevalent at bottom flange-to-web interfaces where debris accumulates, trapping moisture. Static to failure and tests were conducted with and without one million fatigue cycles for each repair type.
All methods but GFRP performed well, restoring the undamaged strength and stiffness of the steel girder regardless of fatigue conditioning. Recommendation for appropriate means of repairing corrosion damaged beam ends are provided.
Harries, K.A., Mash, J.A. & Rogers, C.W. (2022) Corrosion Repair Strategies for Steel Girder Ends Using High Performance and Traditional Materials. PennDOT Report: FHWA-PA-2022-006-PITT WO 002. http://dx.doi.org/10.13140/RG.2.2.24519.78244
In November 2021, a symposium was held to identify knowledge gaps, and research needs and priorities in the bamboo community. Participants who were asked to complete a post-symposium survey on research gaps, needs and priorities. Both rank-order and open-ended questions were asked covering the broad areas of i) determination of material properties, testing and grading; ii) bamboo connection techniques and technology; iii) bamboo durability and fire performance; and, iv) construction using engineered bamboo. This paper reports the survey and its results. Subsequent discussion identifies priorities for future research that can be leveraged to move the use of bamboo in construction forward.
Harries, K.A., Mofidi, A., Naylor, J.O., Trujillo, D., Lopez, L.F., Gutierrez, M., Sharma, B., & Rogers, C. (2022). "Knowledge Gaps and Research Needs for Bamboo in Construction." 18th International Conference on Non-conventional Materials and Technologies (NOCMAT 2022). https://doi.org/10.5281/zenodo.6569785
The withdrawal capacity – as determined by a modified ASTM D1761 test – of screws embedded in Phyllostachys edulis bamboo culm walls is presented, demonstrating capacities and behaviour suitable for structural load bearing applications. This study considers twelve screw type-size combinations and considers whether these are predrilled or the screws are inserted without predrilling, resulting in 20 screw type-size-predrill combinations. For the better-performing screws, average withdrawal parameters exceeding fax = 40 N/mm2 were achieved; twice that determined for three-ply plywood having comparable thickness. Comparison with a comparable dataset of screw withdrawal tests from Guadua angustifolia Kunth bamboo indicates that the value of fax is likely species-dependent. In order to mitigate splitting upon screw insertion into bamboo, screw diameters generally less than 6 mm were required unless the screws are inserted into predrilled holes. There was no advantage observed to using self-drilling screws.
Harries, K.A. ,Morrill, P., Rogers, C.W., Guass, C., Flower, C., Akinbade, Y., & Trujillo, D. (2019). "Screw withdrawal capacity of full-culm P. edulis bamboo." Construction and Building Materials. (216) https://doi.org/10.1016/j.conbuildmat.2019.05.009