998 resultados para Civil Guard


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Derailments due to lateral collisions between heavy road vehicles and passenger trains at level crossings (LCs) are serious safety issues. A variety of countermeasures in terms of traffic laws, communication technology and warning devices are used for minimising LC accidents; however, innovative civil infrastructure solution is rare. This paper presents a study of the efficacy of guard rail system (GRS) to minimise the derailment potential of trains laterally collided by heavy road vehicles at LCs. For this purpose, a three-dimensional dynamic model of a passenger train running on a ballasted track fitted with guard rail subject to lateral impact caused by a road truck is formulated. This model is capable of predicting the lateral collision-induced derailments with and without GRS. Based on dynamic simulations, derailment prevention mechanism of the GRS is illustrated. Sensitivities of key parameters of the GRS, such as the flange way width, the installation height and contact friction, to the efficacy of GRS are reported. It is shown that guard rails can enhance derailment safety against lateral impacts at LCs.

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The non-destructive evaluation of the water permeability of concrete structures is a long standing challenge, principally due to the difficulty of achieving a uni-direction flow for computing the water permeability coefficient. The use of a guard ring (GR) was originally proposed for the in situ sorptivity test, but little information can be found for the water permeability test. In this study, the effect of a GR was carefully examined through the flow simulation, which was verified by carrying out experiments. It was observed that the GR can confine the flow near the surface, but cannot achieve a uni-directional flow across the whole depth of flow. To achieve a better performance, it is essential to consider the effects of the size of the inner seal and the GR and the significant interaction between these two. The analysis of the experimental data has indicated that the GR influences the flow for porous concretes, but there is no significant effect for dense concretes. Further investigation, validated using the flow-net theory, has shown a strong correlation between the water permeability coefficients obtained with the GR (K w-GR) and without it (K w-No GR), suggesting that one dimensional flow is not essential for interpreting data for site tests. Another practical issue was that more than 30 % of the tests with GR failed due to the difficulty of achieving a good seal between the inner and the outer chambers. Based on the work reported in this paper, a new water permeability test is proposed.

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Introduction. On October 26, 2014, Tunisia held its second democratic legislative elections. Participation among more than 5 million registered voters was at about 60%, a relatively good turnout for the country, compared to the 52% voters in 2011. Preliminary results for the 33 constituencies (27 within the country and 6 for expatriates) reveal that secular frontrunner Nidaa Tounes (Call of Tunisia) won around 37% percent of votes while moderate Islamist party Ennahdha, winner of the 2011 elections and leader of Tunisia’s post-revolution government, received 27% of votes. Other parties with notable percentages are the Free Patriotic Union (French: UPL) with 4.4% and the leftist party, Popular Front, with 3.7%. Legislative were immediately followed by two round presidential elections the first one held on November 23, the second one after one month. Conversely to what was expected, people were more attracted by presidential elections even though president has notably less prerogatives than the parliament: representing the state, he is mainly responsible for determining the general state policies in the domains of defense, foreign relations and national security (article 76.) This paradox is ascribed to national imaginary more confident in a “Zaïm” (leader) rather than a collective institution such as a parliament. The turnout was at about 64% within the national 27 constituencies. Out of 70 candidates (including 5 female), 27 (with only one female) met the legal requirements to run for the presidency. The result confirms the legislative trend and Beji Caid Essebsi, leader of Nidaa, was proclaimed the third President of Tunisia. He gained 39.46% of the votes at the first round elections. Essebsi was followed by Moncef Marzouki who received an unexpected score (33.43%) at the first round, thanks to the support of Ennahdha audience and to an active and insistent campaign focused on the idea that revolution is threatened by old regime guard “come-back.” Rewarded for his long militant live, the extreme leftist Hamma Hammami in a new look gained 7,8% of the votes while the new comer Slim Riahi received 5,5% despite rumors circulating on his personal reputation. Notably, Kalthoum Kennou gained 0,55% (18.287 votes) but listed eleventh out of 27.

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Reports cover the calendar year unless otherwise noted.

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O Sistema Nacional de Proteção Civil tem vindo a registar alterações significativas nos últimos dez anos, desde a reestruturação que sofreu em 2006. No mesmo ano, deu-se a criação do Grupo de Intervenção de Proteção e Socorro, aumentando as competências e atribuições da Guarda Nacional Republicana. Com a maturação deste suprassistema, vários sistemas foram implementados para responder às necessidades, designadamente o Sistema Integrado de Operações de Proteção e Socorro, materializado pelo Dispositivo Integrado de Operações de Proteção e Socorro, bem como o aperfeiçoamento do Sistema de Gestão de Operações. Neste sistema, a Guarda insere-se num conjunto de agentes e entidades que concorrem para o mesmo fim, a proteção e socorro. Desta forma, esta investigação tem como objetivos analisar e avaliar o relacionamento entre a Guarda e os diversos agentes de proteção civil no espetro da proteção e socorro, salientando as potencialidades e as vulnerabilidades existentes no Sistema Nacional de Proteção Civil, bem como expor a relevância e a imprescindibilidade da Guarda. A presente investigação regeu-se por uma metodologia de caráter qualitativa, através da realização de inquéritos por entrevista a representantes de agentes e entidades de proteção civil e a elementos da estrutura operacional da Autoridade Nacional de Proteção Civil. Os resultados permitem concluir que, os sistemas implementados facilitam a coordenação e articulação, potenciando a existência de um bom relacionamento entre a Guarda e os agentes de proteção civil, e aumentando, desta forma, a sua eficiência. No entanto, verificam-se falhas a nível institucional, pois, o Sistema Integrado de Operações de Proteção e Socorro abrange entidades de vários Ministérios e entidades não estatais. Estas últimas constituem-se como agentes de proteção civil e assumem uma responsabilização diminuta quando existe atribuição de comando. Constatam-se também falhas no que diz respeito a normas, protocolos e procedimentos, nas relações interpessoais, falta de formação e desconhecimento das missões respeitantes a cada agente interveniente no sistema.

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An earlier CRC-CI project on ‘automatic estimating’ (AE) has shown the key benefit of model-based design methodologies in building design and construction to be the provision of timely quantitative cost evaluations. Furthermore, using AE during design improves design options, and results in improved design turn-around times, better design quality and/or lower costs. However, AEs for civil engineering structures do not exist; and research partners in the CRC-CI expressed interest in exploring the development of such a process. This document reports on these investigations. The central objective of the study was to evaluate the benefits and costs of developing an AE for concrete civil engineering works. By studying existing documents and through interviews with design engineers, contractors and estimators, we have established that current civil engineering practices (mainly roads/bridges) do not use model-based planning/design. Drawings are executed in 2D and only completed at the end of lengthy planning/design project management lifecycle stages. We have also determined that estimating plays two important, but different roles. The first is part of project management (which we have called macro level estimating). Estimating in this domain sets project budgets, controls quality delivery and contains costs. The second role is estimating during planning/design (micro level estimating). The difference between the two roles is that the former is performed at the end of various lifecycle stages, whereas the latter is performed at any suitable time during planning/design.

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This paper aims to develop the methodology and strategy for concurrent finite element modeling of civil infrastructures at the different scale levels for the purposes of analyses of structural deteriorating. The modeling strategy and method were investigated to develop the concurrent multi-scale model of structural behavior (CMSM-of-SB) in which the global structural behavior and nonlinear damage features of local details in a large complicated structure could be concurrently analyzed in order to meet the needs of structural-state evaluation as well as structural deteriorating. In the proposed method, the “large-scale” modeling is adopted for the global structure with linear responses between stress and strain and the “small-scale” modeling is available for nonlinear damage analyses of the local welded details. A longitudinal truss in steel bridge decks was selected as a case to study how a CMSM-of-SB was developed. The reduced-scale specimen of the longitudinal truss was studied in the laboratory to measure its dynamic and static behavior in global truss and local welded details, while the multi-scale models using constraint equations and substructuring were developed for numerical simulation. The comparison of dynamic and static response between the calculated results by different models indicated that the proposed multi-scale model was found to be the most efficient and accurate. The verification of the model with results from the tested truss under the specific loading showed that, responses at the material scale in the vicinity of local details as well as structural global behaviors could be obtained and fit well with the measured results. The proposed concurrent multi-scale modeling strategy and implementation procedures were applied to Runyang cable-stayed bridge (RYCB) and the CMSM-of-SB of the bridge deck system was accordingly constructed as a practical application.

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This paper is a continuation of the paper titled “Concurrent multi-scale modeling of civil infrastructure for analyses on structural deteriorating—Part I: Modeling methodology and strategy” with the emphasis on model updating and verification for the developed concurrent multi-scale model. The sensitivity-based parameter updating method was applied and some important issues such as selection of reference data and model parameters, and model updating procedures on the multi-scale model were investigated based on the sensitivity analysis of the selected model parameters. The experimental modal data as well as static response in terms of component nominal stresses and hot-spot stresses at the concerned locations were used for dynamic response- and static response-oriented model updating, respectively. The updated multi-scale model was further verified to act as the baseline model which is assumed to be finite-element model closest to the real situation of the structure available for the subsequent arbitrary numerical simulation. The comparison of dynamic and static responses between the calculated results by the final model and measured data indicated the updating and verification methods applied in this paper are reliable and accurate for the multi-scale model of frame-like structure. The general procedures of multi-scale model updating and verification were finally proposed for nonlinear physical-based modeling of large civil infrastructure, and it was applied to the model verification of a long-span bridge as an actual engineering practice of the proposed procedures.

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After many years of development BIM (Building Information Modelling) is starting to achieve significant penetration into the building sector of the construction industry. This paper describes the current status of BIM and the drivers that are motivating the change from 2D CAD to BIM within the building sector. The paper then discusses what the implications of the technology underlying BIM may be for the civil construction sector of the construction industry. A project carried out by the Cooperative Research Centre for Construction Innovation is used as an example of this technology as well as several international examples.

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Unmanned Aerial Vehicles (UAVs) are emerging as an ideal platform for a wide range of civil applications such as disaster monitoring, atmospheric observation and outback delivery. However, the operation of UAVs is currently restricted to specially segregated regions of airspace outside of the National Airspace System (NAS). Mission Flight Planning (MFP) is an integral part of UAV operation that addresses some of the requirements (such as safety and the rules of the air) of integrating UAVs in the NAS. Automated MFP is a key enabler for a number of UAV operating scenarios as it aids in increasing the level of onboard autonomy. For example, onboard MFP is required to ensure continued conformance with the NAS integration requirements when there is an outage in the communications link. MFP is a motion planning task concerned with finding a path between a designated start waypoint and goal waypoint. This path is described with a sequence of 4 Dimensional (4D) waypoints (three spatial and one time dimension) or equivalently with a sequence of trajectory segments (or tracks). It is necessary to consider the time dimension as the UAV operates in a dynamic environment. Existing methods for generic motion planning, UAV motion planning and general vehicle motion planning cannot adequately address the requirements of MFP. The flight plan needs to optimise for multiple decision objectives including mission safety objectives, the rules of the air and mission efficiency objectives. Online (in-flight) replanning capability is needed as the UAV operates in a large, dynamic and uncertain outdoor environment. This thesis derives a multi-objective 4D search algorithm entitled Multi- Step A* (MSA*) based on the seminal A* search algorithm. MSA* is proven to find the optimal (least cost) path given a variable successor operator (which enables arbitrary track angle and track velocity resolution). Furthermore, it is shown to be of comparable complexity to multi-objective, vector neighbourhood based A* (Vector A*, an extension of A*). A variable successor operator enables the imposition of a multi-resolution lattice structure on the search space (which results in fewer search nodes). Unlike cell decomposition based methods, soundness is guaranteed with multi-resolution MSA*. MSA* is demonstrated through Monte Carlo simulations to be computationally efficient. It is shown that multi-resolution, lattice based MSA* finds paths of equivalent cost (less than 0.5% difference) to Vector A* (the benchmark) in a third of the computation time (on average). This is the first contribution of the research. The second contribution is the discovery of the additive consistency property for planning with multiple decision objectives. Additive consistency ensures that the planner is not biased (which results in a suboptimal path) by ensuring that the cost of traversing a track using one step equals that of traversing the same track using multiple steps. MSA* mitigates uncertainty through online replanning, Multi-Criteria Decision Making (MCDM) and tolerance. Each trajectory segment is modeled with a cell sequence that completely encloses the trajectory segment. The tolerance, measured as the minimum distance between the track and cell boundaries, is the third major contribution. Even though MSA* is demonstrated for UAV MFP, it is extensible to other 4D vehicle motion planning applications. Finally, the research proposes a self-scheduling replanning architecture for MFP. This architecture replicates the decision strategies of human experts to meet the time constraints of online replanning. Based on a feedback loop, the proposed architecture switches between fast, near-optimal planning and optimal planning to minimise the need for hold manoeuvres. The derived MFP framework is original and shown, through extensive verification and validation, to satisfy the requirements of UAV MFP. As MFP is an enabling factor for operation of UAVs in the NAS, the presented work is both original and significant.