Multi-storey buildings can be subjected to various forms of loading, some of which are of common and frequent nature but others are more extreme and infrequent. The former type includes the self weight of the members and finishes as well as conventional imposed loads such as those due to occupants, furniture, snow, etc. On the other hand, the latter and more severe type of loading can be caused by large explosions, major fires, strong seismic events, or a combination of these effects. Clearly, engineers have to design and construct buildings with appropriate consideration of the different loading conditions that may be experienced by the structure throughout its life cycle. However, the design philosophy can vary significantly depending on the loading under consideration. Whereas a structure is expected to resist conventional loads without suffering any notable damage that can affect its function, the main aim of design against extreme events is to prevent disproportionate collapse and loss of life even at the expense of a substantial repair or replacement cost.This project deals with the performance of building structures under extreme loading conditions, focusing on the ultimate behaviour of floor slabs. The key to preventing disproportionate progressive collapse in a building may largely depend on the ability of floor slabs to deform significantly such that it can carry significant loads through membrane mechanisms rather than conventional bending strength. These membrane mechanisms are vital for the load-carrying capacity in extreme situations such as an unexpected increase in load (e.g. due to the partial collapse of higher floors), increase in actual span (e.g. due to the loss of intermediate supporting elements such as beams or columns) or reduction in the strength in material properties (due to elevated temperature). All of these effects may take place under different, or a combination of, accidental loading scenarios.The main aim of this project is to assess the load-carrying capacity of floor slabs under extreme loading conditions. The research involves an experimental investigation into the performance of reinforced concrete and composite steel/concrete slabs, focusing on the failure condition causing fracture of reinforcement. The tests will examine the influence of important geometric properties, material characteristics and boundary conditions. The experimental results will be used to validate an analytical procedure which can predict the deformation and load levels corresponding to failure. Finally, the findings from the tests and analysis will be used to generate simplified procedures that can be used for the design of floor slabs against extreme loading scenarios. The applicability of the detailed and simplified approaches will also be demonstrated through a number of practical examples. The proposed research will have a direct impact on the safety and competitiveness of the building construction industry in the UK and overseas, consequently leading to a better quality of life through improved structural safety and the efficient use of construction materials.

Soils display strain rate dependant behaviour which has implications for the understanding of a wide range of geotechnical events. However, the current understanding of the results of varying strain rate on soil behaviour are often ignored in design, field studies, laboratory testing and soil mechanics frameworks. Where previous work to understand rate effects has been undertaken it focuses on relatively low strain rates or narrow ranges of strain rates that do not reflect the rates of field events. In addition several field testing techniques rely on the evaluation of rate effects for analysis. These parameters are often derived from costly field studies or specialised laboratory testing. It is the intention through this proposal to examine the behaviour of fine grained soils over a wide range of strain rates whilst varying soil composition. This approach will identify both behaviour at key strain rates and allow understanding of what the main controlling factors are at soil micro structural level. This will be achieved through the use of high speed monotonic triaxial testing with on-sample strain and pore pressure measurement. In parallel the soils will be characterised using simple standardised laboratory testing techniques. The high strain rate testing and standard testing will then be compared to develop a predictive framework which will allow the determination of soil rate potential from standardised laboratory tests without the need for specialised testing or empirical studies. This research study will lead to improved understanding of what soil properties influence rate effect potential and how to quantify them which will be exploitable by academics and industry alike.

Most fire deaths are associated with the remote transport of toxic products produced in hot post-flashover fires, and with carbon monoxide (CO) in particular [S1, S2]. Currently, numerical tools are effective at describing the transport of these toxic products, but incapable of accurately predicting the quantities generated in a fire - thus the source is missing [S2, S3]. In order to extend the scope of fire safety engineering (FSE) methods, and provide more effective tools for practitioners, there is an urgent need for robust and well-validated methodologies which address the problem in its entirety, thus completing the chain and provided a true predictive capability [S3]. This would open the door to a host of new applications, including fire forensics to assist in determining causes of fatalities, supplementing expensive full-scale fires tests, and ultimately in building design, and could transform the application and exploitation of FSE methodologies. It is essential that any such methodology can be effectively exploited by the fire community, so it must be undemanding computationally (so that it can be run on computers typically used by consultants) and must effectively accommodate the specific requirements of real-world fires, i.e. large-scale building scenarios involving a very broad range of lengthscales, and multiple and often complex fuel sources, where significant contributions to toxic products yields may arise both from complex formation processes in the gas phase and directly from the solid-phase, via pyrolysis of combustible boundary materials [S2]. Here an advanced methodology is proposed in which each of these processes can be effectively accommodated, based on the solution of transport equations for each chemical species of interest. The focus of this proposal is on CO prediction, but the method could in future be extended to include other toxic species. The key research question to be addressed is how to most effectively achieve chemical source term closure which is the essential modelling challenge in turbulent combustion systems. Different approaches will be investigated, including a fundamental method based on directly solving the coupled species balance equations using simplified quasi-laminar expressions, and a more sophisticated method which is an extension of the flamelet modelling approach. These predictions will be benchmarked against existing approaches which rely on conventional flamelet representations of toxic product yields and extensions to the simple eddy breakup concept approach, as described in the literature [S4]. The new methods will be validated against relevant experimental data from realistic fire scenarios designed to fully test the generality of the new modelling strategies [S2, S3, S5]. Detailed recommendations will be prepared on exploitation of the methodology, considering the fundamentally competing demands of computational resources and accuracy.References========S1. Babrauskas, V., Levin, B. C., Gann, R. G., Paabo, M., Harris, Jr, R. H., Peacock, R. D. & Yusa, S. (1991) Toxic potency measurement for fire hazard analysis , Special Pub. 827, NIST, Dec 1991S2. Pitts, W.M. (1995) The Global Equivalence Ratio concept and the formation mechanisms of carbon monoxide in enclosure fires , Prog. Energy Combust. Sci., vol. 21, pp. 197-237S3. Purser, D. & Purser, J. (2003) The potential for including fire chemistry and toxicity in fire safety engineering , BRE Client report 202804, 26 Mar 2003S4. Hyde, S.M. & Moss, J.B. (2003) Modeling CO production in vitiated compartment fires , Proc. 7th Int. Symp. Fire Safety Science, pp. 395-406 S5. Smith, D.A., Marshall, N., Shaw, K., & Colwell, S. (2001) Correlating large-scale fire performance with the Single Burning Item test , Proc. 9th Int. Interflam Conf., pp. 531-542

The presence of discrete cracks in a cementitious matrix, often formed as a result of thermal effects and plastic shrinkage during concrete hydration, contributes to deterioration processes such as freeze-thaw action, chloride ingress and carbonation. The independent or sometimes concurrent actions of these processes are partly responsible for reducing the service life of structures, resulting in extensive repair and maintenance regimes which are costing the UK approximately £40 billion per annum. Capillary flow, driven primarily by surface tension, is frequently noted as one of the primary transport mechanisms by which aggressive agents from the environment ingress concrete. Conversely, capillary flow also plays a role in the ability of a concrete to self-heal and recent developments in self-healing technology which mimic biological materials have the potential to dramatically improve the performance and durability of cementitious materials. Self healing cementitious materials containing artificial flow networks which release autogenic (natural) and autonomic (artificial) healing agents upon damage have shown clear evidence of successful healing, characterised by recovery and enhancement of the materials' mechanical and durability properties. Despite this, the interaction of the healing agent with the macro-cracks and micro-cracks in the cementitious matrix has not been investigated and therefore the healing potential of the material cannot be predicted. A number of studies have demonstrated that experimentally observed capillary flow of water and other liquids does not conform to that predicted by standard Lucas-Washburn theory. It is therefore hypothesised that the capillary rise response of healing agents, particularly those with changing viscosity and surface tension, in discrete cracks in cementitious materials will exhibit similar non-conformance. As such, this research proposal concerns the characterisation of the capillary flow characteristics of healing agents in macro-cracks and micro-cracks representative of those formed as a result of predictable material damage occurring during the early life of a structure. This is achieved through experimental investigation of the flow characteristic of the healing agents, including the time-viscosity and time-surface tension relationships and the interaction between the healing agent and the capillary wall during capillary flow. Typical discrete crack widths between 0.05mm and 0.3mm will be formed in cementitious materials and the capillary rise of the healing agent will be captured using a high speed digital camera. The research aims to deliver 2D and 3D numerical models of the flow of healing agents in discrete cracks in cementitious materials including the inflow/outflow to and from the micro-cracked region surrounding the macro-crack, validated by experimental data. The ultimate aim of this field of work is the ability to predict the extent and rate of healing agent movement hence design and produce self-healing cementitious materials with greatly enhanced longevity.

The ability for communities to "bounce back" from major disasters is essential for poverty alleviation and economic development. Termed "disaster resilience", this process is of particular importance in China as rapid economic expansion and urbanization has increased Chinese susceptibility to a number of major disasters, including the 2008 Wenchuan Earthquake. Earthquake-induced landslides represent a particular challenge to resilience as increased rates of landslide hazard may persist for many decades. The proposed research seeks to understand what controls this persistent landslide hazard and the processes that cause landslides to jeopardise recovery. To understand the recovery process and how it affects resilience, we will investigate the role of "social vulnerability" in modifying the response to earthquakes and their related hazards. We will assess the underlying drivers of social vulnerability and the spatio-temporal differences across Sichuan province. We will combine our estimates of landslide hazard and social vulnerability across the decade after the Wenchuan Earthquake, investigating both the spatial patterns of risk and how these change with time. To achieve these goals, we will focus our work on the areas affected by the Wenchuan Earthquake, where the Chengdu Institute of Technology-State Key Laboratory of Geohazard Prevention and Geoenvironment Protection has created an incredibly large dataset of landslide hazards since the earthquake. In collaboration with landslide scientists and social scientists at Cardiff University's Sustainable Places Research Institute, we will expand this dataset in two ways; (1) increasing the resolution of landslide hazard mapping to understand the relative role of aftershocks and rainfall in controlling hazard, and (2) using local census data to understand social vulnerability and how the interaction between social vulnerability and landslide hazards has changed in space and through time. The unprecedented detail of our data will enable us to develop a new probabilistic landslide hazard model that incorporates landslides caused by both aftershocks and rainfall events that can be applied across earthquake-prone China and perhaps even globally. Field data collected as part of this effort will help to constrain threshold values and so help support the construction of a landslide early warning system for Sichan. Finally, we will model the resilience of the built environment and key infrastructure through state of the art machine learning algorithms. As evidence of our commitment to improve the welfare of earthquake-prone China through better planning for disasters we will engage with an extensive network of governmental and non-governmental institutions. From the first day of the grant we will engage with organisations with interests in both science and policy to achieve this goal. We will also model resilience under different demographic and policy scenarios, using this as a tool to understand and communicate the challenges of building resilient communities.