Search

On December 26, 2004 a great earthquake (M-W 9.3) occurred off the western coast of Sumatra triggering a series of tsunami waves that propagated across the Indian Ocean causing damage and life loss in 12 countries. This paper summarizes the observations of lifeline performance, building damage and its distribution, and the social and economic impact of the tsunami made by the Earthquake Engineering Field Investigation Team (EEFIT) in Thailand and Sri Lanka. EEFIT operates under the umbrella of the UK's Institution of Structural Engineers. It is observed that good engineering practice can reduce economic losses, but additional measures are required to reduce risk to life.

This paper proposes a new moment resisting detail for use in earthquake resistant structures. The wedge detail tested in this project is a new design that builds upon the idea of inducing a plastic hinge away from the column face to dissipate the energy that would otherwise yield the connection. The plastic capacity of the beam is locally reduced by decreasing the depth of the web and reforming the flange to the new beam profile. This makes the section more plastic, so reducing the buckling problem suffered by other reduced section joints. Laboratory testing shows that the joint is capable of plastic rotations greater than 0.05 rad without any significant loss of energy dissipation capability, which is far in excess of the requirements for a joint given by the latest standards based on post-Northridge data.

Recently, it has come to light that footbridges may have problems with human induced vibrations if their lateral period of vibration is of the order of 1 s. This has been highlighted by the much-publicized case of the Millennium Footbridge in London. This paper describes a similar problem associated with the historic Cragside Bridge built circa 1875. This bridge is a wonderful historic bridge built in the grounds of Cragside Manor in Northumberland, United Kingdom by the famous Industrialist Lord Armstrong. An investigation of the bridge revealed that it suffered vibration problems resulting from insufficient lateral stiffness. When lightly loaded (approximately six people) the fundamental lateral natural frequency of vibration was 2.6 Hz. This mode was predominantly a lateral mode of vibration. A computer model of the bridge was developed and various loading scenarios were investigated. As the bridge is very lightweight, the computer model showed that the natural frequency could reduce to 1.12 Hz if the bridge was loaded to 4 kPa. Extra stiffening elements were added to the computer and, depending on the superimposed load, the frequency could be increased from 1.12 to 1.57 Hz (for a 4 kPa uniform live load) and increased to 3.67 Hz for an imposed load equivalent to approximately nine people. It is believed that this will help to remedy the problem, but further research is being conducted to reduce the problem further.

A materially non-linear plane-frame model is presented that is capable of analysing high-rise buildings subjected to earthquake forces. The model represents each storey of the building by an assembly of vertical and horizontal beam elements The model introduces yield hinges with ideal plastic properties in a regular plane frame. The displacements are described by the translation (sway) of each floor and the rotation of all beam-column intersections. The mass is only associated with the translations, and thus the analysis can be carried out as a static condensation of the rotations, combined with integration of the dynamic equations for the translations. The dynamic integration is here carried out by use of the Runge-Kutta scheme. This approach allows a building to be modelled by m(n+2) degrees of freedom (where m is the number of storeys and n is the number of bays). The rank of the condensed stiffness matrix is only m. Its construction, which requires the inversion of the rotational, rank m(n+1), stiffness matrix, is required only at time-steps where the pattern of yielding has altered from the previous time-step. This model is particularly attractive for non-linear response history analysis of high-rise buildings as it is efficient, allows each storey to have multiple redundancies, and each connection to be modelled with any suitable moment-rotation relationship. Three verification examples are presented and the results from static push-over analysis are compared with time-history results from the simplified model. The results verify that the model is capable of performing non-linear response history analysis on regular high rise buildings.

The increasing effects of climate change and extreme weather events on the operation of power systems highlight the need for developing effective techniques and models for evaluating the challenges that power systems may have to deal with in the future for maintaining high levels of resilience. Within this context, the aim of the `Resilient Electricity Networks for Great Britain (RESNET)' project is to develop and demonstrate a comprehensive approach to analyse the effects of climate-related changes on the resilience of the Great Britain's electricity system, and to develop tools for quantifying the value of adaptation measures that would enhance its resilience. This paper presents an overview of the key research activities and findings of RESNET project, specifically addressing possible climate change implications related to demand and supply scenarios, component ratings, and impact of extreme weather on system reliability. The final aim is to provide insights on various climate and weather-related challenges that the Great Britain's electricity system might face in the future.

Infrastructure systems are vitally important to our society as they deliver the goods and services that communities require to function. This reliance on infrastructure systems makes any disruption to their functioning liable to result in disproportionate consequences to communities. In this paper we investigate key parameters that exist in real world networks in an attempt to uncover the driving forces of network generation and evolution. We then present a network model that can reproduce networks with several non-trivial properties that are the key signature of real infrastructure networks. By changing the drivers that control evolution of our synthetic networks, the model can potentially help us to better predict what a future infrastructure network may look like, and how resilience it will be to future hazards.

Summary Background Hand eczema (HE) is a multifactorial disease, comprising different aetiological conditions and different morphologies. There are two aetiologically distinct groups of HE recognised: exogenous, such as contact dermatitis (allergic and/or irritant HE) and endogenous, such as the classic hyperkeratotic HE. Differences in the skin barrier properties of these two conditions could theoretically be expected. Aim To examine whether differences exist in the lipid profile and the susceptibility of the stratum corneum (SC) in patients with allergic/irritant HE and those with hyperkeratotic HE. Methods Using cyanoacrylate, SC samples were taken from 23 patients with allergic/irritant HE and 15 with hyperkeratotic HE for lipid analysis by high-performance thin-layer chromatography (HPTLC). Samples were also taken from adjacent, unaffected skin. Severity of HE was assessed by the Hand Eczema Severity Index (HECSI), and skin barrier susceptibility was assessed by measuring transepidermal water loss (TEWL) after a 24-hour patch test with sodium lauryl sulfate (SLS). Results No statistically significant difference was found between groups for the lipid analysis or for skin susceptibility to SLS. We found a significantly higher HECSI score for hyperkeratotic HE compared with irritant or allergic HE (P = 0.02). Conclusions There appears to be no difference in skin barrier between allergic/irritant HE (exogenous eczema) and hyperkeratotic HE (endogenous eczema) with regard to SC lipids or susceptibility to SLS.

A simplified procedure, which is a modification of the shear beam model, has been developed and applied to treat the seismic analysis of asymmetric buildings. This three dimensional procedure accounts for torsional coupling and the bending rotations at beam–column junctions and it can be used with a personal computer to give fast and reasonably accurate results, which compare well with those from comprehensive finite element analysis. This procedure will therefore be useful for preliminary seismic analysis and design of buildings.

This paper describes the observations made by a reconnaissance team following the 22nd February 2011, Mw 6.3, Christchurch, New Zealand earthquake (GNS Science, 2011). The team comprised of members of the UK based Earthquake Engineering Field Investigation Team who spent 5 days collecting observations on damage resulting from the earthquake. Although the magnitude of this earthquake was not particularly high (Mw 6.3), the shallow focus and close proximity resulted in locally very high ground motions, widespread damage and 182 fatalities. The earthquake is also particularly notable for the widespread liquefaction it caused, landslides and rockfalls in the hills south of Christchurch, and the significant damage suffered by unreinforced masonry and historic structures. Over wide areas of central Christchurch, recorded accelerations were in excess of those required by the current New Zealand seismic loadings standard (NZS1170.5:2004: Standards New Zealand 2004) and therefore the earthquake presented a valuable opportunity to assess performance of modern buildings under code-level ground acceleration.

Air traffic networks are essential to today’s global society. They are the fastest means of transporting physical goods and people and are a major contributor to the globalisation of the world’s economy. This increasing reliance requires these networks to have high resilience; however, previous events show that they can be susceptible to natural hazards. We assess two strategies to improve the resilience of air traffic networks and show an adaptive reconfiguration strategy is superior to a permanent re-routing solution. We find that, if traffic networks have fixed air routes, the geographical location of airports leaves them vulnerable to spatial hazard.

As our climate continues to respond to anthropogenic forcing, the magnitude and frequency of individual weather events and the intensity of the weather extremes associated with these, re -mains highly uncertain. This is a particular concern for our infrastructure networks, as increasing storm-related damage to these vital lifelines has significant consequences for our communities. Effective first response is hence becoming an increasingly important part of the management of infrastructure systems. Here, we propose a novel and rational framework for 'consequence forecasting' that enables probabilistic, pre-event decision-making for first responders to effec-tively target resources prior to an extreme weather event and thus reduce the societal conse-quences. Our method is unique in that it minimises model bias by using the same numerical weather prediction model for both fault attribution and fault prediction. Our framework can predict failure rates that are within 50% of the true value for more than 50% of the events considered, some 24 h in advance, therefore demonstrating that it can be an important part of increasing societal climate resilience by reducing reinstatement times.

The 2010 eruption of the Eyjafjallajokull volcano had a devastating effect on the European air traffic network, preventing air travel throughout most of Europe for 6 days (Oroian in ProEnvironment 3:5–8, 2010). The severity of the disruption was surprising as previous research suggests that this type of network should be tolerant to random hazard (Albert et al. in Nature 406(6794):378–382, 2000; Strogatz in Nature 410(6825):268–276, 2001). The source of this hazard tolerance lies in the degree distribution of the network which, for many real-world networks, has been shown to follow a power law (Albert et al. in Nature 401(6749):130–131, 1999; Albert et al. in Nature 406(6794):378–382, 2000). In this paper, we demonstrate that the ash cloud was unexpectedly disruptive because it was spatially coherent rather than uniformly random. We analyse the spatial dependence in air traffic networks and demonstrate how the combination of their geographical distribution and their network architectures jeopardises their inherent hazard tolerance.