Now showing 1 - 10 of 40
  • Publication
    'Outside their Comfort Zone': Diverse and Engaging Approaches for Students Learning through a Different Discipline
    (Access and Lifelong Learning, University College Dublin, 2019-05-29)
    I am an engineer and typically engineering students are assessed using calculation-based exams and written laboratory reports. However, I teach a 5-credit third year module which typically contains 60 architecture students and is compulsory. Simultaneously, these students complete a 20-credit module in studio design involving approximately 30 contact hours per week. The purpose of this module is to provide architecture students with the necessary training in engineering to fulfil requirements at both a professional and accreditation level. Whereas calculation-based exams are commonplace in the assessment of engineering students, using them to assess architecture students does not promote effective learning. It was not uncommon for architecture students to fail the engineering-style exam which suited those with a strong background in maths and physics. They seemed relatively unfamiliar with exams as a form of assessment as most of their submissions are studio portfolios. Exams tend to focus student attention on ‘reproductive thinking’ (Boud and Dochy, 2010). Students often end up cramming last minute, engaging in surface learning rather than the deep learning associated with ‘slow scholarship’ when assessment tasks require substantial involvement over time (Gibbs and Simpson, 2005). An alternative, more inclusive assessment approach was required for this module to improve engagement, to allow equal opportunity to demonstrate learning, to cater for the diversity of students and to reduce the need for individual adaptations for specific students.
      88
  • Publication
    Dynamic Load Allowance
    Chapter 4 provides a good explanation of the current state-of-the-art for the influence of dynamics on bridge traffic loading. It starts with an explanation of the concepts and a review of the various definitions used in the field, such as Dynamic Amplification factor and Impact Factor. It looks at how some of the main codes of practice in the world treat dynamics. A considerable portion of the chapter deals with the statistics of dynamic amplification. It is noted that the biggest dynamic amplifications tend to occur for light vehicle loading events. A statistical approach addresses this issue and provides a more appropriate allowance for dynamics which is called Assessment Dynamic Ratio. The influence of road surface roughness is considered and the implications of a local irregularity or pothole, as sometimes happens near the end joints. A number of field measurement campaigns of dynamic amplification are reported from various countries. These largely support the findings of the numerical studies.
      153
  • Publication
    A Two-Stage Direct Integration Approach to Find The Railway Track Profile Using In-Service Trains
    (Civil Engineering Research Association of Ireland, 2020-08-28) ; ;
    The railway track is an important element in transportation networks. In recent years, drive-by monitoring of railways has become more popular. Using data measured from in-service trains, the railway profile can be found. In previous research, a complex optimiziton method is used to calculate the railway profile. This paper introduces a new two-stage direct integration approach to find the same track profile much more efficiently. The calculated track profile is similar to a ‘true’ profile and can be used to monitor the condition of the track.
      236
  • Publication
    A Numerical Study of the Effect of Wind Barriers on Traffic and the Bridge Deck
    (Civil Engineering Research Association of Ireland, 2020-08-28) ; ;
    Wind actions can have a great impact on both bridges and traffic on bridges. However, structures designed to shelter the traffic from wind can influence the aerodynamic performance of the bridge deck, especially for long-span bridges. This study compares the effect of non-perforated walls and perforated walls used as wind barriers for traffic by conducting Computational Fluid Dynamics (CFD) simulations on three-dimensional geometries of a four-lane bridge deck. Steady-state simulations employ the Reynolds-Averaged Navier Stokes (RANS) method with the k-epsilon turbulence model and all simulations use parallel computing. An open-sourced software OpenFOAM is used.
      197
  • Publication
    Using Instrumented Quarter-Cars for 'Drive By' Bridge Inspection
    This paper investigates the concept of ‘drive by’ bridge inspection, a low cost alternative to Structural Health Monitoring (SHM), involving no sensors on the bridge. The concept may be of particular value after an extreme event, such as an earthquake or a flood, where a rapid indication of bridge condition is needed. Vehicle/bridge dynamic interaction is modelled to test the effectiveness of the approach. Damage is simulated here as a change in the bridge damping ratio. Two quarter cars are simulated crossing the bridge with accelerometers on board. A frequency domain analysis then illustrates changes in the Power Spectral Density of the accelerations as the bridge becomes damaged. The time-lagged difference in the accelerations is found to be effective in detecting damage. Results are compared to those with sensors on the bridge and found to be similar.
      323
  • Publication
    Using instrumented vehicles to detect damage in bridges
    (Faculty of Engineering, University of Porto, 2012-07-22) ; ; ;
    Bridge structures are subject to continuous degradation due to the environment, ageing and excess loading. Monitoring of bridges is a key part of any maintenance strategy as it can give early warning if a bridge is becoming unsafe. This paper will theoretically assess the ability of a vehicle fitted with accelerometers on its axles to detect changes in damping of bridges, which may be the result of damage. Two vehicle models are used in this investigation. The first is a two degree-of-freedom quarter-car and the second is a four degree-of-freedom halfcar. The bridge is modelled as a simply supported beam and the interaction between the vehicle and the bridge is a coupled dynamic interaction algorithm. Both smooth and rough road profiles are used in the simulation and results indicate that changes in bridge damping can be detected by the vehicle models for a range of vehicle velocities and bridge spans.
      767
  • Publication
    Allowing for a rocking datum in the analysis of drive-by bridge inspections
    'Drive-By' damage detection is the concept of using sensors on a passing vehicle to detect damage in a bridge. At highway speeds, the vehicle spends a short amount of time on the bridge: it may not even go through a full cycle of vibration, resulting in only a partial signal of the bridge motion being detected. Given that the spectral resolution of standard signal processing techniques depends on the length of data in the signal, they cannot be used to identify the bridge frequency accurately. In addition, the nonlinear and non-stationary nature of the vehicle-bridge interaction system poses challenges. The aim of this study is to model a 'drive-by' bridge inspection approach using a beam in free vibration. An optimisation approach is proposed in numerical simulations as an alternative to standard signal processing techniques to overcome the challenges of short signals and the nonlinear nature of the drive-by system.
      190
  • Publication
    An Overview of Arup Computational Fluid Dynamics Projects
    In recent years, end users have become more concerned with the human experience and the personal comfort of the individual is becoming more important in the design of the built environment. Computational Fluid Dynamics (CFD) is a tool that permits assessment of personal comfort. CFD is a stream of fluid mechanics that utilises numerical methods to analyse and solve problems involving fluid flows. The fundamental basis for these problems are the Navier-Stokes equations. While research applications of CFD are developing, as it the use of CFD in the aerospace industry, the use of CFD in Civil Engineering applications is currently at the cutting edge. Arup have recently developed a team to work on such projects and some of these will be presented in this paper. The paper will discuss the research question of each project, the methodology adopted in developing the models, the results of the simulations and some lessons learned going forward. Based on the projects done to date, it can be concluded that CFD has been shown to be a powerful tool that adds valuable information to fluid flow problems.
      251
  • Publication
    A Direct Integration Approach to Drive-by Damage Monitoring of Railway Tracks
    Railway tracks can be monitored by visual inspection or, more recently, indirectly using inertial sensors installed in a passing vehicle. Defects in the track such as depressions in the profile or points of low stiffness (e.g. hanging sleepers) interact dynamically with passing vehicles and can be detected with accelerometers and gyrometers. This can be achieved using special purpose track recording vehicles or through instrumentation of regular trains in service. It has been shown in previous research that an optimisation procedure can be applied to back-calculate track profiles from vehicle-mounted sensor data. This involves finding the profile that gives a best fit to the measured data. In this paper, a new direct integration approach is introduced to find the same track profile in a fraction of the computing time. The Newmark-Beta method is used. Compared with the profile calculated using the optimisation algorithm, the results are similar. However, direct integration is much more efficient than optimisation and allows the calculation to be completed in a fraction of the time. The calculated track profile can be used to estimate points of low stiffness.
      169
  • Publication
    The analysis of short signal segments and its application to Drive-by bridge inspection
    (Seventh Sense Research Group, 2015-05) ;
    ‘Drive-By’ damage detection is the concept of using sensors on a passing vehicle to detect damage in a bridge. At highway speeds, the vehicle spends a short amount of time on the bridge: it may not even go through a full oscillation, resulting in only a partial signal of the bridge motion being detected. Given that the spectral resolution of standard signal processing techniques depends on the length of data in the signal, they cannot be used to identify the bridge frequency accurately. In addition, the nonlinear and non-stationary nature of the vehicle-bridge interaction system poses challenges. An optimisation approach is proposed here as an alternative to standard signal processing techniques to overcome the challenges of short signals and the nonlinear nature of the drive-by system. Signal pollution due to the road profile is overcome using time-shifted bridge curvatures, a novel damage indicator.
      107