Structures

Staff

• Professor Omar Laghrouche
• Professor Dimitri Val
• Professor Malcolm Chrisp
• Associate Professor Demitrios Cotsovos
• Associate Professor George Vasdravellis
• Associate Professor Benny Suryanto
• Assistant Professor Shadi Mohamed

General Information

Our Structures research group has substantial expertise in physical testing, including large-scale testing, and numerical and analytical modelling of structures and their components, particularly concrete, steel and composite steel-concrete structures. Research also encompasses structural dynamics and vibrations, soil-structure interaction, structural reliability and sustainability, structural health monitoring and novel Finite Element (FE) techniques.

Current research topics include: structural typologies for multi-hazard resilience, demountable structural systems for sustainable construction, RC structural response under seismic and high-rate loading, self-centering steel and composite moment resisting frames, reliability-based assessment of existing structures, sustainability of concrete structures, and reliability of structures for offshore renewables.

Members of this group are also involved in Railways Research focusing on the developments required for modern rail networks, which include the need to cope with more traffic, heavier loads and higher speeds. Current research topics in this area include numerical modelling of train-track critical velocities and mitigation strategies, numerical modelling of high-speed train induced ground vibration and propagation, full scale experimental modelling of railway track and geosynthetic reinforcement technologies.

Research has been funded by the UK Research Councils, European Commission and private sector.

Case studies/Recent research projects

LOCORPS: Lowering the Costs of Railways using Preformed Systems

EPSRC funded, Prof. O. Laghrouche

This project aims to evaluate and produce design guidance for two novel embankment replacement systems as a means to potentially reduce the cost of constructing new high-speed railway lines (particularly in urban environments) and improve the overall track behaviour and hence passenger experience.

Steel-concrete composite beams using precast hollow-core slabs and a demountable shear connection mechanism

EPSRC funded, Assoc. Prof. G. Vasdravellis

The project used experimental testing complemented by numerical analyses in order to develop the proposed novel structural system. Experiments were conducted on both the slab-steel section connection system alone, in order to characterise its structural behaviour, and on large-scale composite beams replicating real beams in buildings. The experiments provided evidence on the physical behaviour and the ultimate failure modes of the proposed system, whereas numerical simulations using advanced mathematical models were used to study numerous geometrical configurations and generalise the results of the tests. Based on the results of the tests and the simulations, recommendations for the practical design of the proposed system have been proposed.

Multi-Wavelength Sized Finite Elements for Three Dimensional Elastic Wave Problems

EPSRC funded, Prof. O. Laghrouche

The aim of this research project is to accurately model three dimensional elastic wave problems with fewer finite elements and without refining the mesh at each frequency. The resulting improvement in computational efficiency will enable problems of practical interest to be simulated using computing facilities available in most engineering design offices. Applications include geophysical prospecting and location of hydrocarbon reserves, but also problems involving vibrations caused by roads and railways, elastic waves caused by piling of foundations, earthquake wave propagation and aseismic design.

CBF-EQRES: Novel concentrically braced frame for seismic resilience

EC-Horizon 2020 funded, Assoc. Prof. G. Vasdravellis

The project developed a seismic-resistant steel frame for high seismic resilience. Replaceable energy-dissipative hourglass shape pins made of duplex stainless steel that results in high post-yield stiffness were in series connected to the frame concentric braces. Replaceable fuses were also introduced at the locations of the frame beams where plastic hinges were expected to develop. The project used an integrated experimental-numerical research methodology to evaluate the seismic performance of the proposed configuration.

REUSE: Reusable steel-concrete composite floors

EC-Horizon 2020 funded, Assoc. Prof. G. Vasdravellis

This project proposes a novel way to connect precast concrete slabs with steel sections that offer the advantages of a) off-site fabrication of all components; b) easy and fast installation on the construction site; c) disassembly of the composite floor; and d) direct reuse of all components in new projects. The project uses experimental testing complemented by numerical analyses to develop the proposed novel structural system. Based on the results of the tests and the simulations, recommendations for the practical design of the proposed system will be proposed.

ClimatCon: Climate-resilient pathways for the development of concrete infrastructure: adaptation, mitigation and sustainability

EC-Horizon 2020 funded, Prof. D. Val

To respond to challenges posed by climate change new approaches to sustainable development combining mitigation and adaptation are needed. The development of such approaches was addressed in this project in the context of concrete infrastructure. The project developed a comprehensive method based on an integration of the Life-Cycle Assessment (LCA) and Life-Cycle Cost Analysis (LCCA) techniques for the evaluation of the whole life performance of reinforced concrete (RC) structures subjected to carbonation in conditions of climate change. Both experimental studies and numerical modelling were carried out. The method took into account both adaptation and mitigation measures and due to numerous uncertainties involved in such analysis was based on a probabilistic approach.

Investigating the Actual Capacity of Half-Joints with Theoretically Inadequate Reinforcement Detailing

Funded by Highways England through Balfour Beatty Mot Macdonald Joint Venture, Assoc. Prof. D. Cotsovos, Assoc. Prof. B. Suryanto

The project investigated the performance of half-joints of actual bridge beams using large-scale testing and numerical modelling.

UPP-SUD: Unlocking the Potential of Precast in Sustainable Urban Development

British Council Newton Institutional Links – Ristekdikti funded, Assoc. Prof. B. Suryanto

This project aims to unlock the potential of precast construction in developing countries. More specifically, the project develops a novel lightweight prefabricated sub-assemblage system utilising a damage-tolerant cement composite with locally-sourced low-carbon constituents. Central to the proposed system is the ability of the sub-assemblages to remain within the serviceability limit whilst dissipating forces under major earthquakes. Proof of concept is currently being developed through testing full-scale sub-assemblage prototypes under design-level earthquake.

BOND: Influence of casting position on lap and anchorage strength of embedded steel reinforcement

IStructE and Concrete Centre funded, Assoc. Prof. B. Suryanto

This project aims to develop recommendations for the casting position factor used in the determination of basic bond strength of reinforcement in Eurocode 2. The value of the coefficient, the classification of criteria for good/poor bond conditions, the stiffness of support to the bars, and the consistency of the concrete are considered.

Laboratory/testing facilities

The Heavy Structures laboratory houses the UK’s largest (recently upgraded) laboratory based railway track test facility (GRAFT II). It also offers a range of other testing facilities and equipment. These include: large-scale testing facilities (recently used to test full-scale pre-stressed concrete bridge beams to failure for Highways England), facilities for testing structural components or scaled models of structures under different loading conditions (ranging from static monotonic to high frequency cyclic loading), impact (drop-weight) testing facilities. In addition, it is equipped with state-of-the-art hydraulic actuators for large-scale testing, high capacity self-reacting machines and specialized equipment for material testing.