PhD Studentship: Compressive Behavior of Self-Expanding Concrete-Filled CFRP Tube Columns

Today's urban landscape is defined largely by steel and concrete buildings, bridges and roads, which have started to degrade at an increased rate in the last 30 years due to corrosion of steel, degradation and scour, creep and cracking of concrete. The expenses for concrete building rehabilitation and maintenance are immense: €200B was spent on restoration of concrete structures alone in 2018 (for the EU27 countries). The proposed research addresses these problems by focusing on circular concrete columns, which are critically important structural elements in construction of buildings, parking garages and bridges or piers. In these applications there are many advantages in using precast or in-situ cast concrete filled fibre reinforced polymer (FRP) tube columns using self-compacting concrete (SCC): The columns are – compared to conventional RC columns – lighter in weight, do not need a formwork nor concrete compaction (SCC), and the FRP tube can be designed to (partially or totally) replace the need for a transverse and longitudinal steel reinforcement. In addition, concrete filled carbon FRP (CFRP) tubes (CFFTs) confine the inner concrete core increasing the strength and ductility of the column and its durability in harsh environments. The mechanics of conventional circular FRP-confined concrete columns has been studied by many researchers, who have confirmed that the load carrying capacity, stiffness, and ductility of such elements is similar to circular columns repaired by full wrapping with externally bonded FRP sheets and fabrics. This project will build on the available knowledge and will use a proprietary, highly expansive SCC, which will be restrained after casting by prefabricated CFRP tubes. Researchers at the Swiss Federal Laboratories for Materials Science and Technology (Empa) have successfully developed the highly expansive SCC based on a combination of calcium sulfo-aluminate expansive agent, super absorbent polymers, shrinkage reducing agent, and short PP fibers, and have proven that a self-prestress of high-modulus CFRP is feasible. The use of this SCC in CFFT columns is an ideal application for the expansive concrete in which the FRP tube would protect it from humidity variations hence guaranteeing a stable state and constant internal confinement pressure in the FRP tube. This will be monitored by hoop strain monitoring with the aid of novel embedded distributed fibre optic sensors (DFOS) in the CFRP tube wall. The project will also make use of novel pseudo-ductile hybrid FRP wrap materials, also developed at Empa, thus combining multiple material innovations to develop new types of structural elements with previously unknown performance and mechanics.

Eligibility: 

Minimum entry qualification - an Honours degree at 2:1 or above (or International equivalent) in a relevant science or engineering discipline, possibly supported by an MSc Degree. Ideal candidate must have background in either Civil, Structural or Mechanical Engineering.

Further information on English language requirements for EU/Overseas applicants.

Funding: 

Tuition fees + stipend are available for Home/EU and International students

The candidate will periodically spend time on research visits to EMPA of 2-6 weeks. Additional funding for the programme related costs will be provided by EMPA.

Applications are also welcomed from self-funded students.

Further information and other funding options.

Further Information:

EMPA: www.empa.ch/web/s304

The University of Edinburgh is committed to equality of opportunity and inclusivity for all its staff and students: www.ed.ac.uk/equality-diversity

Principal Supervisor: Professor Luke Bisby

Assistant Supervisor: Prof Giovanni Terrasi

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