Bridge Layout Research Articles

Do Chairs Reduce a Navigator’s Mobility? Pilot Study on the Influence of Navigation Bridge Design on Lookout Routines

Abstract Despite technological progress in the maritime industry, navigators are still the final link of the decision-making chain and rely not only on equipment, but also on human senses. Visual observation of the vessel’s surroundings still plays a crucial role in navigation. Four different ships in service were visited to investigate the work of professional navigators and carry out a pilot experiment on real crews to test the methods for future full-scale research. The main objective was to better understand the influence of bridge design on lookout routines of navigators, while the additional goals were to check the presence of navigators in certain parts of the bridge and to determine if it is reasonable to forbid navigators to sit, as the practice is still used on some ships. Considering space limitations and differences in layouts of the wheelhouse, rarely mentioned in this kind of study, the movement of watch-keeping officers was analysed. In total, twenty observations were made to generate the heatmaps of presence during the routine duties. The results of the research indicate that many factors, including bridge design and layout of equipment, might affect lookout routines but it is possible to find similar patterns on the bridges of different shapes and arrangements. The pilot experiment confirms that it is reasonable to carry out a full-scale study, as there is still room for improvement in the area of ergonomic bridge design. Better understanding of modern lookout and movement routines might lead to the development of adequate ergonomic regulations and result in increased work comfort and the well-being of seafarers.

Optimization of heat transfer and friction characteristics of a rotating U-channel with a combination of variable size connecting bridges

Gas turbine blades typically feature a U-shaped or multi-flow snake channel in their mid-chord region, both incorporating a 180° turn. However, the addition of fins and dimple or protrusion turbulent flow structures can result in excessive pressure losses within the flow channel. This study aims to reduce pressure loss and improve flow uniformity by inserting one to three connecting bridges of varying sizes in the gap between the two channels. The suitability of various connecting bridges with different angles and sizes is assessed in both stationary and rotating states through simulations. Subsequently, the cooling efficiency and reduction in resistance performance of different-sized connecting bridge combinations are evaluated. A layout scheme for optimal connecting bridge placement within the U-shaped channel is proposed. Results indicate that the incorporation of a single minimum-size connecting bridge leads to an average 22.6 % decrease in overall flow resistance within the U-shaped channel, and simultaneously yields a 3.5 % increase in the overall thermal performance. When using the recommended connecting bridge angle and layout combinations, the incorporation of connecting bridges leads to an average 46 % and 49.7 % reduction in overall flow resistance within the U-shaped channel in order to counterbalance pressure losses generated by turbulent structures. This effect consequently results in a 6.5 % and 6.6 % increase of the overall thermal performance. This study offers new insights and data-backed evidence that can potentially facilitate the design of high-efficiency and low-resistance cooling methods in the mid-chord region of high-temperature turbine blades.

Nonlinear dynamic behaviour and seismic fragility analysis of irregular multi-span RC bridges

This paper investigates the nonlinear dynamic behaviour and failure probability of multi-span Reinforced Concrete (RC) bridges supported on piers of unequal heights. To this end, a three-dimensional nonlinear finite element model of RC bridges with substructure irregularity is developed. The model is verified against an available experimental data of a large-scale shake table test results of a benchmark irregular two-span RC bridge. Six hypothetical two-span irregular RC bridges with piers varied in height, and various superstructure mass-distribution conditions (equal and unequal) and a regular bridge layout (as a reference) are considered. Through Incremental Dynamic Analyses (IDAs), the seismic performance of selected bridge layouts is investigated at both local and global scales. Finally, the influence of bridge layout on seismic vulnerability of piers of varying heights is analysed. Results show that the unbalanced seismic displacement demand and failure probability of different bents of a multi-span irregular RC bridge significantly depend on the height of piers and their arrangement. Therefore, the typical presumption of shorter piers having a higher failure probability due to their higher seismic force absorption is not always the most possible failure mechanism.

Ion sensitive AlGaN/GaN field-effect transistors with monolithically integrated wheatstone bridge for temperature- and drift compensation in enzymatic biosensors

We present a pH-sensitive AlGaN/GaN ion sensitive field-effect transistor (ISFET) with monolithically integrated Wheatstone bridge layout and demonstrate the possibility to identify and to compensate the influence of cross-sensitivities to environmental changes, such as temperature, without the need of an external electronic circuit. Based on this Wheatstone-approach low-drift penicillinase-modified AlGaN/GaN solution-gate field-effect transistors (PenFET) with an ultrathin Al2O3 gate coating were prepared and exhibit improved stability and sensitivity compared to PenFETs with conventional wet chemically oxidized gate surface over a course of 60 days as they yield a denser, more homogeneous enzyme layer on the gate area. Moreover, using the Wheatstone-approach can identify a loss of physisorbed enzymes as the dominant aging mechanism for shorter time-periods and stable operation conditions after a period of 10 days with an extracted average Michaelis constants of (20 ± 4) μM for the immobilized enzyme layer by quantitative evaluation applying a kinetic model.By application of the Wheatstone-approach for acetylcholinesterase-modified AlGaN/GaN solution-gate field-effect transistors (AcFET) as a model, we demonstrate that temperature-induced drift can be differentiated from substrate-induced signals and a substantial loss of immobilized enzymes over the course of 12 days after production can be identified.

Study on Urban Bridge Layout Oriented by Slow-Traffic and Lingering Space - Taking Shanghai Suzhou Creek as an Example

Through the investigation of bridges along Shanghai Suzhou Creek, we find a lot of problems. Firstly, Bridge layout is unreasonable. Secondly, mobiles occupy the main traffic volume. Thirdly, slow-traffic and lingering space isn’t comfortable. This study proposes the bridge planning and design idea oriented by slow-traffic and lingering space. Learning from overseas experiences, we put forward the bridge layout suggestions for Suzhou Creek from three aspects. First is to construct the reasonable distance between slow-traffic and lingering bridges. Second is to build the bridge system suitable for fast and slow-traffic. The last is to connect the cross-river attracted sources and bridges. Based on the above, we propose the bridges layout suggestion plan of Suzhou Creek.

Maritime Usability Study by Analysing Eye Tracking Data

The aim of the Integrated Navigation System (INS) on a ship bridge should be to provide the navigator with added value and aid in the complex task of conducting a safe and efficient passage at high speeds in demanding waters. This article presents a method for analysing eye tracking data to reveal sub-optimal design in the bridge layout and in the software graphical user interface on a maritime navigation display. The analysis of eye tracking data with a focus on scan path events indicates sub-optimal design, and the paper provides suggestions for improvement in design and interfaces. Pros and cons of using Eye Tracking Glasses in a maritime environment are presented. The importance of not affecting the normal behaviour of the navigator by collecting data is stressed, and how the software should provide good visualisation and interpretation of the eye tracking data.

효율적인 어업실습선의 선교 layout을 위한 당직항해사의 업무특성 분석

효율적인 어업실습선의 선교 layout을 위한 당직항해사의 업무특성 분석

The Link between Past and Present: Bicycle and Pedestrian Underslung Girder Bridge over the river Neman in Lithuania/Die Verbindung von Vergangenheit und Gegenwart: eine unterspannte Fahrrad- und Fußgängerbrücke über die Memel in Litauen

This paper presents a recent experience in Lithuania, concerning a bridge characterized by a particular typology, considerably long mid-span and the preservation of the ancient abutments. The advantages of the selected bridge layout are described using the example of the bicycle pedestrian bridge spanning river Neman in Alytus, focusing on the general conception, static calculation and design as well as construction. The underslung girder bridge passes through a nationally important recreation landscape and was required to be designed and constructed with a particular regard to the natural environment as well as historical background.

Hybrid simulation of a multi‐span RC viaduct with plain bars and sliding bearings

SummaryThis paper deals with the seismic response assessment of an old reinforced concrete viaduct and the effectiveness of friction‐based retrofitting systems. Emphasis was laid on an old bridge, not properly designed to resist seismic action, consisting of 12 portal piers that support a 13‐span bay deck for each independent roadway. On the basis of an OpenSEES finite element frame pier model, calibrated in a previous experimental campaign with cyclic displacement on three 1:4 scale frame piers, a more complex experimental activity using hybrid simulation has been devised. The aim of the simulation was twofold: (i) to increase knowledge of non‐linear behavior of reinforced concrete frame piers with plain steel rebars and detailing dating from the late 1950s; and (ii) to study the effectiveness of sliding bearings for seismic response mitigation. Hence, to explore the performance of the as built bridge layout and also of the viaduct retrofitted with friction‐based devices, at both serviceability and ultimate limit state conditions, hybrid simulation tests were carried out. In particular, two frame piers were experimentally controlled with eight‐actuator channels in the as built case while two frame piers and eight sliding bearings were controlled with 18‐actuator channels in the isolated case. The remaining frame piers were part of numerical substructures and were updated offline to accurately track damage evolution. Copyright © 2015 John Wiley & Sons, Ltd.

Development of Alignment-Based Parametric Data Exchange Schema for Bridge Geometry

The benefits of using building information modeling to integrate the project delivery process by exchange of project data between industry stakeholders stimulate the bridge industry to develop bridge information modeling. However, the existing data exchange methods, formats, and standards that are used by the building industry cannot be directly borrowed and used “as is” for bridge projects. Bridge projects involve specific definitions of structural geometry (e.g., roadway alignment–driven bridge layout) or definitions of bridge member geometry that are not usually used in building projects (e.g., camber data for steel plate girders). These bridge-oriented geometries cannot be described by using current building-oriented data exchange formats. Because bridge geometry depends on the geometry of the roadway carried by the bridge, it is beneficial to define a bridge as a parametric model that can be manipulated by modifying a manageably small number of independent parameters (e.g., station and skew). However, the existing data exchange standards do not support the exchange of parametric geometry. To overcome these technical limitations, this paper presents a software-neutral schema for the exchange of alignment-driven bridge-oriented parametric geometry data using eXtensible Markup Language. The application of this formalism is then illustrated via three high-priority use cases that occur during the steel bridge life cycle.

Effect of a Time Dependent Concrete Modulus of Elasticity on Prestress Losses in Bridge Girders

Prestress losses assumed for bridge girder design and deflection analyses are dependent on the concrete modulus of elasticity (MOE). Most design specifications, such as the American Association of State Highways and Transportation Officials (AASHTO) bridge specifications, contain a constant value for the MOE based on the unit weight of concrete and the concrete compressive strength at 28 days. It has been shown in the past that that the concrete MOE varies with the age of concrete. The purpose of this study was to evaluate the effect of a time-dependent and variable MOE on the prestress losses assumed for bridge girder design. For this purpose, three different variable MOE models from the literature were investigated: Dischinger (Der Bauingenieur 47/48(20):563–572, 1939a; Der Bauingenieur 5/6(20):53–63, 1939b; Der Bauingenieur, 21/22(20):286–437, 1939c), American Concrete Institute (ACI) 209 (Tech. Rep. ACI 209R-92, 1992) and CEB-FIP (CEB-FIP Model Code, 2010). A typical bridge layout for the Dallas, Texas, USA, area was assumed herein. A prestressed concrete beam design and analysis program from the Texas Department of Transportation (TxDOT) was utilized to determine the prestress losses. The values of the time dependent MOE and also specific prestress losses from each model were compared. The MOE predictions based on the ACI and the CEB-FIP models were close to each other; in long-term, they approach the constant AASHTO value. Dischinger’s model provides for higher MOE values. The elastic shortening and the long term losses from the variable MOE models are lower than that using a constant MOE up to deck casting time. In long term, the variable MOE-based losses approach that from the constant MOE predictions. The Dischinger model would result in more conservative girder design while the ACI and the CEB-FIP models would result in designs more consistent with the AASHTO approach.

링크분석에 의한 우리나라 근해대형트롤선의 선교 레이아웃 개선에 관한 기초연구

The purpose of this study is to obtain a basic data on layout of the trawlers` bridge equipment. The task activities of bridge workers involved in the navigation and fishing operation were analyzed by link analysis methods. The results are as follows. It was found that the movement pattern and frequency of bridge workers are different accordance with the bridge work (navigation, casting net, towing net and hauling net). The central workstation of movement of the bridge workers was a radar workstation, a steering workstation and a trawl winch workstation in the bridge work. But the radar did not show up as the center of movement during the hauling net. Workstations related deeply to the central workstations of the movement on the bridge were as below. Radar workstation was related to a GPS plotter, a microphone location for external communication with VHF and MF/HF equipment and a steering in the case of the navigation, the steering, the GPS plotter and the net monitor in the case of the fishing operation. Steering workstation was related deeply to the GPS plotter, the radar in the case of the navigation, a speed controller, the GPS plotter, a fish finder, the net monitor and the microphone location in the case of the fishing operation. Trawl winch workstation showed deep relation with the GPS plotter and the speed control during the fishing operation. Through this study, it was found that Workstations related deeply to the central workstation of the movement of the bridge workers in accordance with the bridge work. The results of this study might be utilized as the basic data on the bridge layout to minimize the fatigue degree due to a physical movement of the bridge workers.

Research on Fairway Condition for Safety Navigation in Bridge Waters

Bridge construction can promote economic development, but if the bridge layout is unreasonable, it would hinder ship’s safety navigation in the bridge area. There is little reference for fairway width design about curved bridge channel in inland river navigation standards of China. The fairway conditions for ship safety navigation in bridge waters were discussed in this paper, and the mentioned determination methods for fairway dimension in bridge waters in this paper can provide some reference to solve other channel design problem.

Simulation Analysis of ECDIS’ Route Exchange Funcionality Impact on Navigation Safety

Abstract Modern Integrated Navigation Systems (INS) integrate information obtained from various sensors and functions. Processed data are presented on the computer display generally with the aim to increase navigator’s situation awareness and to reduce his/her workload. The investigations described in the paper were carried out to assess the advantages of the new functionality of the test INS (e-Navigation enhanced Integrated Navigation System ee-INS), developed in the EU financed EfficienSea Project, that looks and works like a standard ECDIS. This new functionality implements ‘Exchange of Intended Route’ service. The experiment was conducted in a full mission ship simulator environment with 20 experienced mariners. The bridge layout without ECDIS ‘Exchange of Intended Route’ functionality, and bridge layout with this functionality implemented, was applied in research and its results enabled to carry out their comparison. The navigators’ workload was measured by NASA-TLX method. Navigators’ situation awareness in respect to other ship’s state and the final passing distance were utilized to evaluate safety of navigation process.

Close Framework CAD System Development on Airport Project

Close framework structure becomes recently a competitive solution for taxiway bridges. Due to no pile foundation construction, it has short duration and significant economic benefits. The development of close framework CAD system adopts Visual Basic and bases on secondary development interface in AutoCAD VBA to draw construction plans, such as structure diagram, bridge layout, prestressed tendons and ordinary reinforced chart. Another feature is the automatic generation of materials amount Excel tables and model for finite element analysis. The main program code of graphic object realization and deign parameters import are described. For the unique professional characteristic in airport project, the software system has a considerable engineering prospect.

Corrections to “Piezoresistive Strain Sensors and Multiplexed Arrays Using Assemblies of Single-Crystalline Silicon Nanoribbons on Plastic Substrates” [Nov 11 4074-4078

The above titled paper (ibid., vol. 58, no. 11, pp. 4074-4078), contains two errors, both relating to nomenclature associated with the Wheatstone bridge layout of the sensors. The corrections are presented here.

Design and Construction of the Perschling Bridge, Austria

This paper presents a recent experience from Austria, concerning a bridge characterized by a particular shape of the abutments and considerable slenderness, and by a casting of the superstructure performed in two steps. A durable and low-maintenance structure could be achieved because of the reduction of high-maintenance elements like sealing and pavements. The advantages of the selected bridge layout are described using the example of the Perschling Bridge in Austria focusing on the general bridge conception, static calculation, design as well as construction.

Topology optimization of continuum structures with different tensile and compressive properties in bridge layout design

In order to solve elasticity problems with dual extension/compression modulus this paper presents a technique that employ Heaviside function to describe the nonlinear relationship of stress and mat...

An application of Bayesian networks for the optimization of a bridge layout

Advantages in the adoption of integrated systems on a ship's bridge are quantified with respect to a more traditional bridge layout. The study is performed by modelling the causation factor for a ship-to-ship collision scenario. The assessment is provided in terms of the probability distribution of the time required to the officer on the watch (OOW) to complete a foreseen procedure aimed at avoiding a collision with another ship. The time needed to identify and agree the evasive manoeuvre with the second ship is evaluated for the two layouts, considering also a probabilistic occurrence of disturbances distracting and delaying the OOW during the procedure. Bayesian networks are employed to model the scenario. A general increment of the reactivity of the OOW in the integrated bridge is seen, represented by a shorter time to complete the procedure and by a reduced probability of being interrupted. The overall effect is an increase in the time available to put into practice the manoeuvre itself and, eventually, to avoid the collision.

Thrust and Guide Devices for Launched Bridges

Incremental launching is a competitive construction method for medium-span (40–65 m) prestressed concrete bridges. It does not constrain the length and width of the superstructure, and bridges longer than 1 km and wider than 20 m have been successfully launched. This method is hardly constrained by the bridge layout, as varying plan curvatures can be solved by shifting launch supports and varying vertical curvatures by shimming the bottom edges of the superstructure. The launch of a prestressed concrete bridge involves enormous forces and requires the guide and control of big volumes. The devices used for this purpose are described along with their design criteria and optimum fields of utilization, and several suggestions derived from many years of launching practice are given.