Now showing 1 - 10 of 12
  • Publication
    Dynamic Behaviour of Arches
    (University College Dublin, 2018-06-08)
    Dynamic behaviour of arches • Assessment of bridges for “real” trains • UIC 776 – 1R o Full dynamic analysis, or o Static analysis + dynamic amplification factors • Dynamic amplification factors o Based on simply supported beams o Fundamentally not appropriate for arches o Overally conservative
      127
  • Publication
    Enabling Global Engagement at UCD
    (University College Dublin, 2018-04-18)
    Ireland’s economic success is dependent on its ability to engage flexibly in a global environment. Currently Ireland hosts world or European headquarters for over one thousand multinational companies, including nine of the top ten global ICT companies and fifty percent of the world’s leading financial services firms, and is the second most attractive country globally, after Singapore, for foreign direct investment. Globally operating companies and institutions require globally aware and globally competent graduates – this imperative led to formalising UCD’s thinking in the area of globalisation and the launch of the UCD Global Engagement Strategy for the period 2016 – 2020. UCD’s vision for 2020 is to “bring the best of the world to Ireland and the best of Ireland, including its distinct cultures, to the world” and in so doing UCD, currently Ireland’s most global university, will become a world-leading global university. Five key strategic objectives have been identified: • internationalise the UCD experience ensuring that a global outlook will permeate the daily activities of all staff, students, faculty and alumn. • extend and develop strategic relationships thereby providing opportunities for faculty to partner in collaborative research and education, for students and staff to participate on mobility programmes and for worldwide alumni to engage with each other. • grow our global reputation for excellence in education, research, innovation and impact through coordinated engagement with institutions, government, non-government agencies and industry. • increase the global impact of our scholarship, research and innovation by effectively communicating the impact of our excellence in research and education to our key international audiences. • further develop an enabling environment for UCD’s global activities by internal improving policies and supports that enhance the efficient creation of a culturally diverse environment. Professor Paul Fanning, currently UCD Deputy Vice-President for Global Engagement, will identify some of the challenges arising from this strategy and also some of the measures taken to address them. These measures include the establishment of UCD Global Centres, the establishment of joint institutions and double degree programmes, and the implementation of institution wide policies to support staff and students in achieving our global engagement objectives. It is hoped that sharing these challenges, many of which are, or will be, faced by other international institutions intending to extend their activities more globally, will promote debate, and eventually smoother resolutions of them, to the benefit of all institutions operating in an increasingly global environment.
      117
  • Publication
    Load tests on arches
    (2018-06-08)
    Load Testing • Expensive, disruptive, time consuming • Why? – Improved understanding of structural response of bridge – Verify serviceability load capacity in conjunction with an assessment tool – Validate numerical models – Complex irregular geometries – …….. • Rich source of data & understanding
      116
  • Publication
    Mechanical behaviour and 3D stress analysis of multi-layered wooden beams made with welded-through wood dowels
    This paper presents experimental and numerical investigations on multi-layered timber beams using welded-through wood dowels in place of traditional poly(vinyl acetate) (PVAc)-adhesives (or metallic nails). Four-layer beams were constructed with varying numbers of dowels, in each, and then loaded using four-points bending tests to evaluate the mechanical performance of these beams. The practical difficulties encountered in constructing deeper multi-layer beams are discussed and possible solutions which have been employed for the purpose of this work, and proved successful are presented. In order to investigate thoroughly the full potential of multi-layered beams with a very limited number of experimental studies, a 3D FE model has been presented, validated against experimental results and then used to study some influential parameters. The results showed that a reasonable bending stiffness of multi-layered beams is achievable with a good combination of material and geometric parameters.
      1301Scopus© Citations 72
  • Publication
    The Evolving Dynamic Response of a Four Storey Reinforced Concrete Structure During Construction
    Structures include elements designated as load bearing and non-load bearing. While non-load bearing elements, such as facades and internal partitions, are acknowledged to add mass to the system, the structural stiffness and strength is generally attributed to load bearing elements only. This paper investigates the contribution of non-load bearing elements to the dynamic response of a new structure, the Charles Institute, in the grounds of University College Dublin (UCD) Ireland. The vertical vibration response of the first floor and the lateral response at each floor level were recorded at different construction stages. The evolution of the structural response as well as the generation of a finite element (FE) model is discussed. It was found that the addition of the non-load bearing facades increased the first floor natural frequency from 10.7 Hz to 11.4?Hz, a change of approximately +6.5%. Similarly these external facades resulted in the first sway mode having its frequency increased by 6%. The subsequent addition of internal partitions, mechanical services and furnishings resulted in the floor natural frequency reducing to 9.2 Hz. It is concluded that external facades have the net effect of adding stiffness and the effect of internal partitions and furnishings is to add mass. In the context of finite element modelling of structures there is a significant challenge to represent these non-structural elements correctly so as to enable the generation of truly predictive FE models.
    Scopus© Citations 14  529
  • Publication
    Factors affecting traffic-generated vibrations on structures and the masonry minaret of Little Hagia Sophia
    Increasingly buildings and their occupants are negatively impacted by traffic–induced vibrations. The continuous application of vibrations is particularly detrimental for historic masonry buildings and for very modern structures constructed of strong and light materials. Population and land development trends indicate greater proximity of traffic flow near buildings in coming years. This paper outlines the factors influencing the frequency content and the magnitude of vibrations on nearby structures in an attempt to enable local communities and their designers to be more proactive in vibration mitigation. Using these described factors, the paper assesses the effects of traffic-induced vibrations on a portion of a monumental masonry building: the minaret of Little Hagia Sophia Mosque (former Byzantine Church of the Saints Sergius and Bacchus) based on adjacent railway field measurements.
      912
  • Publication
    Masonry Arch Bridges: Analysis Tools for Assessment - Finite Element Methods
    (University College Dublin, 2018-06-08)
    Finite element modelling of engineering structures works well when: • Geometry is well defined • Material properties (linear and nonlinear regimes) are well defined and understood • Loading and boundary conditions are clearly defined • All of the above are challenging in respect of stone or masonry arch bridges
      85
  • Publication
    Testing and long-term monitoring of a curved concrete box girder bridge
    apital investment in national infrastructure is significant. The need to maintain and protect critical infrastructure links has led in recent years to significant developments in the area of structural health monitoring. The objective is to track a structure’s long-term performance, typically using sensors, and to successively compare the most recently measured responses with prior response history. During construction of the West Street On-Ramp, a curved concrete box girder bridge, located in the city of Anaheim (California), eleven accelerometers were permanently installed on its bridge deck. The associated data acquisition system was configured to record once a specified threshold acceleration response was exceeded; during the period 2002–2010 a total of 1350 datasets including six earthquakes, for each of the eleven sensors, were acquired. This automatically acquired data was supplemented, during the summer of 2009, with responses measured during controlled vehicle tests. Six accelerometers were additionally installed on the frame of the weighed test vehicle. This paper presents the findings of the analyses of these measured data sets and serves to inform owners and managers as to the potential feedback from their instrumentation investment. All response histories were analyzed using frequency domain techniques for system identification. Extraction of the modal characteristics revealed a continuous reduction, of approximately 5%, in the first three natural frequencies over the period of the study. The measured responses from the vehicle sensors are discussed in the context of identifying the potential for bridge frequency measurement using instrumented vehicles.
      530Scopus© Citations 71
  • Publication
    Experimental study of timber-to-timber composite beam using welded-through wood dowels
    This paper presents exploratory research related to novel full-scale multi-layered timber beams with composite action achieved with welded-through wood dowels. Different multi-layer beam designs, where the timber layers were interconnected with welded wood dowels providing interlayer shear resistance, were tested in bending with different dowel densities. The main originality of this study is the achievement of dowel welds through greater depths of sections than has previously proved possible. The practical difficulties encountered in constructing deeper multi-layer beams, and the successful solutions arrived at, are discussed. The significance of the research reported is the demonstrated ability to produce multilayered timber sections which are structurally efficient and do not require non timber based joining agents such as nails or adhesive.
      1331Scopus© Citations 47
  • Publication
    Investigation of the Rail-Induced Vibrations on a Masonry Historical Building
    Increasingly historic masonry buildings are subjected to higher levels of traffic and rail vibrations due to urbanization and population growth. Deterioration and destabilisation of these buildings may result, especially if they were previously damaged (e.g. earthquakes or settlement problems). To better understand building response, vibration measurements were conducted on the Little Hagia Sophia Mosque, located adjacent to Istanbul’s Sirkeci-Halkali railway line. Transport-induced vibrations were recorded at several points on the ground and building. Attenuation characteristics in the ground and amplification features on the building were examined. Peak particle velocities often exceeded previously established thresholds for human perception and in some cases for structural damage. These are evaluated with respect to the building’s condition.
      816Scopus© Citations 7