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Will Hawkins

PhD updates

19/10/18 Project Update

October 18, 2018

My PhD project is now entering its latter stages, and recent work has therefore focused primarily on analysis, writing and publication. Two journal papers have recently been published on the project; the first detailing a strength design methodology for TRC shells and the second describing the design, construction and testing of two quarter-scale specimens:

  • Hawkins, W., Orr, J., Ibell, T., Shepherd, P. 2018. An Analytical Failure Envelope for the Design of Textile Reinforced Concrete Shells. Structures, 15. doi: 10.1016/j.istruc.2018.06.001

  • Hawkins, W., Orr, J., Shepherd, P., Ibell, T. 2018. Design, construction and testing of a low carbon thin-shell concrete flooring system. Structures. (accepted for publication, October 2018).

Work has now begun on writing my PhD thesis, starting with the main bodies of research completed so far and concluding with detailed ‘real-world’ case studies and comparisons with other common floor structures. Preliminary results indicate that the proposed thin-shell floor structures offer significant savings in embodied energy over both concrete and steel floor systems across a range of spans.

The figure shows finite element analysis results showing predicted deformed shape and cracking of shell test specimens

18/04/18 Project Update

April 17, 2018

A novel analytical strength design approach has been developed for textile reinforced concrete (TRC) shells, such as the flooring system being developed in this PhD project. Compared to existing methods, the proposed model significantly reduces physical testing requirements and thus allows faster exploration and optimisation of shell thickness and reinforcement. The model was verified through physical tests and the results written into a journal paper currently under review. For the specimens tested, the proposed method increases the predicted strength by up to a factor of 3.7 compared to existing methods, whilst remaining conservative, and hence its use could lead to significant material savings and new applications for TRC shells.

 

A detailed analysis of the physical tests undertaken on prototype shell floors has also been undertaken. This included the creation of a detailed finite element model, where the nodes and element thicknesses were modified individually to match the measured geometry of the specimen, allowing an assessment of the structural effects of manufacturing errors. This work has been written into a paper to be presented at the 2018 IASS Symposium in Boston, USA. 

 

The results verify the analysis method and provide further evidence of the high structural efficiency of the proposed flooring system. Considerable savings in embodied materials for building structures can now be demonstrated with confidence as the project progresses towards detailed case-studies and practical implementation at full-scale.

19/10/17 Project Update

October 18, 2017

A series of investigations into the performance of various shell geometries were carried out in early 2017. Each tested geometry corresponded to a specific formwork construction method, including timber (constructed from straight elements), fabric (form-found using dynamic relaxation) and CNC milled (free-form). These findings were written into a conference paper and presented at the IASS Symposium 2017 in Hamburg.

A design procedure was established involving parameterisation and automated optimisation of the cross-vault geometry, thus minimising shell thickness, reinforcement requirements and embodied energy. Multiple loadcases and support conditions are considered in the optimisation routine to create a high-performance structure for real-world building applications.

Download the full report via the link below

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