124 research outputs found
A Review of Trip Planning Systems.
This report reviews current information provision in all modes of transport and assesses the needs for and benefits of trip planning systems. The feasibility of trip planning systems is discussed given the current state of technology and information availability and supply. The review was stimulated by technological developments in telecommunications and information technology which are providing the possibility of a greatly enhanced quality of information to aid trip planning decisions. Amongst the conclusions reached were the following: Current information provision is considered deficient in many respects. Travellers are often unaware of alternative routes or services and many are unable to acquire adequate information from one source especially for multi-modal journeys. In addition, there is a lack of providing real time information where it is required (bus stops and train stations) and of effective interaction of static and real time information. Most of the projects, which integrate static and dynamic data, are single mode systems. Therefore there is a need for an integrated trip planning system which can inform and guide on all aspects of transport. Trip planning systems can provide assistance in trip planning (before and during the journey) using one or a number of modes of travel, taking into account travellers preferences and constraints, and effectively integrating static and dynamic data. Trip planning systems could adversely affect traffic demand as people who become aware of new opportunities might be encouraged to make more journeys. It could also affect travellers choice as a result of over-saturation of information, over-reaction to predictive information, and concentration on the same 'best' routes. However, it can be argued, based on existing evidence, that such a system can benefit travellers, and transport operators as well as the public sector responsible for executing transport policies. Travellers can benefit by obtaining adequate information to help them in making optimal decisions and reducing uncertainty and stress associated with travel. Public transport operators can benefit by making their services known to customers, leading to increased patronage. Public transport authorities can use the supply of information to execute their transport policies and exercise more control over traffic management
Fatigue life of an anchored blind-bolt loaded in tension
This paper investigates and reports on the fatigue behaviour of a novel blind-bolt system termed the Extended Hollo-bolt (EHB). The new blind-bolt is a modified version of the standard Lindapter Hollo-bolt, and its application relates to the construction of bolted, moment-resisting connections between open profile beams and concrete-filled tubular columns. The fatigue behaviour of the system is studied on the basis of constant amplitude loading tests, with a total of 56 experiments being reported. The specimens were subjected to tensile loading for various stress ranges, with the repeated load being selected relative to the design yield stress of the blind-bolt's internal shank. The influence of testing frequency and strength of concrete infill is also examined. An analysis of the results indicates that an increase in the concrete strength can increase the fatigue life of the EHB system. Within the tested range, the failure mode of the EHB under repeated loading was found to be due to internal bolt shank fracture, a mode which is consistent with its monotonic behaviour and also comparable with standard bolt–nut–washer system behaviour. The experimental results (S–N data) were further compared with the Eurocode 3 Part 1-9 guidelines. The fatigue design strength of the anchored EHB blind-bolt is found to be adequately represented by the current specification detail Category 50 that is provided for standard bolting systems
Performance of T-stub to CFT joints using blind bolts with headed anchors
This paper assesses the performance of a newly developed blind bolt, intended for use in constructing bolted moment-resisting connections to concrete-filled tubular steel profiles. A total of ten connection tests are reported, with each configuration having been subjected to a predominantly tensile force in a representation of the tension region of a typical moment connection. The test variables included type of fastener, addition of concrete to the tube, strength of the concrete, spacing among bolts, and bolt class. On the basis of reformability response, the benefits of filling the tubular member with concrete are highlighted. The favorable performance that results from using a relatively, high-grade concrete infill is also highlighted. The addition of a concrete infill to the tube stiffens and strengthens the otherwise relatively
flexible tube walls, enhancing overall connection behavior in terms of stiffness, strength, and ductility. The performance of connections to concrete-filled tubular steel profiles using blind bolts with headed anchors is shown to be suitable for moment-resisting construction
Study on photocatalytic performance of rutile phased TiO2 micro size rods/flowers film towards methyl orange degradation
Pure rutile titanium dioxide (TiO2) film was fabricated at low temperature of l 50°C by hydrothe1mal method. TiO2 film was developed on Fluorine doped tin oxide (FTO) by using titanium butoxide (TBOT) as a precursor, hydrochloric acid (HCI) and deionized (DI) water. The surface morphology of rutile phased TiO2 films were studied by Field Emission Scanning Electron Microscopy (FESEM). X-ray Diffraction (XRD) was used to analyze the structural prope1ty of the films. EnergyÂdispersive spectroscopy (EDX) was used to verify the elemental property of the films. The photocatalytic degradation of methyl orange (MO) was observed by using UV-vis spectroscopy. The photocatalytic analysis was conducted to compare the ability of rutile phased TiO2 film and P25 film (commercial TiO2). The pH solution was varied from pH 3 to IO to study the favorable pH of TiO2 film. The MO concentration was varied from 5 to 15 ppm to find the limited reaction of TiO2 film. The optimum amount of HCI concentration was 15.88 mol/L while the optimum amount of TiO2 loading was 0.123 mol/L. The optimize reaction time was obtained at 10 hours. No degradation was observed after IO hours. The result shows, 0.123 mol/L TBOT concentration of 1225 nm/ has the highest degradation of MO. The degradation was up to 65.6 % while P25 film was 8.07 % only. MO degradation became insignificant at high concentration. From the experiments, it was found that the rutile phased TiO2 has the higher photocatalytic activity in lower MO concentration and favorable in acidic environment
Evaluation of current practice and associated challenges towards integrated design
The AEC industry is highly interested in effective ICT adoption and deployment, including its utilization within the design process. However, its capabilities have not yet been fully exploited and it is an obvious area for further research. Architects and engineers tend to have some technological support to monitor and evaluate the possible impacts of decisions made throughout the design process. Many aspects are left out of consideration and the entire project is broken up into independent fragments or domains that are combined together at a later, post hoc stage. Impact of separate decisions on each others have to be interpreted on a person-to-person basis between the involved design stakeholders.
This paper attempts to evaluate current design practice and associated challenges towards design integration with advanced technologies, such as BIM, by conducting an online survey targeted at designers and engineers, who are most affected by its emerging issues. The outcomes of this study are presented and analysed, concluding that the current design process fails to meet expectations and needs improvements. It goes further to propose the requirements for an integrated system as a means for an effective solution for the identified problem
Fatigue Life of Extended Hollobolt Connection in Concrete Filled Tube
Studies on the performance of blind bolt connections have been carried out by many researchers. A number of recent studies of new blind bolted connection system have been proposed. The system uses the so called Extended Hollobolt fastener to connect the concrete filled tubular columns. The strength performance of this system has been investigated under both monotonic and cyclic loading. However, the performance of such connections under fatigue loading is still unknown. Therefore, a study to investigate the fatigue performance of Extended Hollobolt was proposed. The main objective of this study is to provide a better understanding of the fatigue life of the proposed blind bolt, consequently provides the design guidance for Extended Hollobolt connection in concrete filled tube. A number of tests were conducted to determine the effect of the frequency and the level of stress range loading on the behaviour of the Extended Hollobolt. The tests were used grade 8.8 bolts subjected to tension. Results show that the frequencies between 0.2 Hz to 5 Hz does affect fatigue life and the stress-range versus fatigue life behaviour of Extended Hollobolt follows the expected pattern of behaviour of standard bolts. The test results of Extended Hollobolt under different stress range then further compared to the normative regulation Eurocode 3. The fatigue life or behaviour of Extended Hollobolt is found to be higher than the theoretical curve of Eurocode 3. Meanwhile, the failure mode of Extended Hollobolt is similar to the standard bolt which is a very positive outcome for blind bolt. However, fatigue life for standard bolt appears to be higher
A component method model for blind-bolts with headed anchors in tension
The successful application of the component-based approach – widely used to model structural joints – requires knowledge of the mechanical properties of the constitutive joint components, including an appropriate assembly procedure to derive the joint properties. This paper presents a component-method model for a structural joint component that is located in the tension zone of blind-bolted connections to concrete-filled tubular steel profiles. The model relates to the response of blind-bolts with headed anchors under monotonic loading, and the blind-bolt is termed the "Extended Hollo-bolt". Experimental data is used to develop the model, with the data being collected in a manner such that constitutive models were characterised for the principal elements which contribute to the global deformability of the connector. The model, based on a system of spring elements, incorporates pre-load and deformation from various parts of the blind-bolt: (i) the internal bolt elongation, (ii) the connector’s expanding sleeves element, and (iii) the connector’s mechanical anchorage element. The characteristics of these elements are determined on the basis of piecewise functions, accounting for basic geometrical and mechanical properties such as the strength of the concrete applied to the tube, the connection clamping length, and the size and class of the blind- bolt’s internal bolt. An assembly process is then detailed to establish the model for the elastic and inelastic behaviour of the component. Comparisons of model predictions with experimental data show that the proposed model can predict with sufficient accuracy the response of the component. The model furthers the development of a full and detailed design method for an original connection technology
Hysteretic performance of a new blind bolted connection to concrete filled columns under cyclic loading: An experimental investigation
The structural performance and reliability of a new blind-bolting technique is investigated in this study. The new blind-bolt is termed Extended Hollobolt (EHB) and is a modification of the standard Hollobolt. The EHB enhances the tensile resistance and stiffness of the fastener by anchoring it in the concrete infill of a tubular column. This paper reports on an investigation into the cyclic behaviour of end-plate connections to concrete filled tubular (CFT) columns using the EHB. A series of six full-scale connections were tested under quasi-static cyclic loading. The key parameters investigated were amplitude of cyclic loading procedure, bolt grade, tube wall thickness, and concrete grade. The strength, stiffness, rotation capacity and energy dissipation capacity of the connections were evaluated at different load cycles. The EHB provided stable hysteretic behaviour with appropriate level of strength and stiffness, where strength is comparable to that of standard bolt-and-nut fasteners and where rigid behaviour can be achieved. The influence of tube wall thickness and concrete grade on the performance of the connection in terms of strength, stiffness, ductility and failure mode is investigated. It is shown that the required performance can be achieved by controlling the tube wall thickness and concrete strength. The results indicate that the connection can offer energy dissipation capacity and ductility appropriate for its potential use in seismic design. © 2012 Elsevier Ltd
BIM extension for the sustainability appraisal of conceptual steel design
Contemporary advancements in Information Technology and the efforts from various research initiatives in the AEC industry are showing evidence of progress with the emergence of building information mod- elling (BIM). BIM presents the opportunity of electronically modelling and managing the vast amount of information embedded in a building project, from its conception to end-of-life. Researchers have been looking at extensions to expand its scope. Sustainability is one such modelling extension that is in need of development. This is becoming pertinent for the structural engineer as recent design criteria have put great emphasis on the sustainability credentials in addition to the traditional criteria of structural integrity, constructability and cost. With the complexity of designs, there are now needs to provide deci- sion support tools to aid in the assessment of the sustainability credentials of design solutions. Such tools would be most beneficial at the conceptual design stage so that sustainability is built into the design solu- tion starting from its inception. The sustainability of buildings is related to life cycle and is measured using indicator-terms such as life cycle costing, ecological footprint and carbon footprint. This paper proposes a modelling framework combining these three indicators in providing sustainability assessments of alterna- tive design solutions based on the economic and environmental sustainability pillars. It employs the prin- ciples of feature-based modelling to extract construction-specific information from product models for the purposes of sustainability analysis. A prototype system is implemented using .NET and linked to the BIM enabled software, Revit StructuresTM. The system appraises alternative design solutions using multi-crite- ria performance analysis. This work demonstrates that current process and data modelling techniques can be employed to model sustainability related information to inform decisions right from the early stages of structural design. It concludes that the utilized information modelling representations – in the form of a process model, implementation algorithms and object-based instantiations – can capture sustainability related information to inform decisions at the early stages of the structural design process
Dynamic response of a laterally-loaded infinite rigid cylinder embedded in a saturated poroelastic medium
In this paper, an analytical solution for the response of a rigid cylinder embedded in a full-space poroelastic medium subjected to a dynamic lateral load is derived. The problem is idealised as a two-dimensional problem. The solution is obtained using Biot’s theory for acoustic waves. In this solution, the displacements of the solid skeleton and the pore pressure are expressed in terms of three scalar potentials. These potential correspond to the wave velocities of the slow and fast compressional wave and to the shear wave. The governing equation for the dynamic motion is expressed in the frequency domain using Fourier transformation and the potentials are shown to be given by Holmholtz equations
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