Deck Design Research Articles

Assessment of static aerodynamic stability bridge with computational and experimental method

The bridge is the connector between two separate places. In order to manufacture the bridge, it needs to be divided into segments. Each certain distance and each segment has a cross-sectional shape in the form of a deck. Long-span bridges require aerodynamic stability due to the wind blow whose speed is varied. In order to obtain a stable design of the bridge deck, there are two complementary methods, namely the method of computation and experimentation. This paper discusses the application of computational methods and experimental for a deck of long spans bridge. The results of the simulation and experiment are in the means of aerodynamic characteristics, i.e. curve of lift, drag and moments coefficient. Aerodynamic stability can be concluded from the results of these methods.

Reliability-based maintenance optimization of corrosion preventive designs under a life cycle perspective

Sustainability is of paramount importance when facing the design of long lasting, maintenance demanding structures. In particular, a sustainable life cycle design for concrete structure exposed to aggressive environments may lead to significant economic savings, and to reduced environmental consequences. The present study evaluates 18 different design alternatives for an existing concrete bridge deck exposed to chlorides, analyzing the economic and environmental impacts associated with each design as a function of the maintenance interval chosen. Results are illustrated in the context of a reliability-based maintenance optimization on both life cycle costs and life cycle environmental impacts. Maintenance optimization results in significant reductions of life cycle impacts if compared to the damage resulting from performing the maintenance actions when the end of the service life of the structure is reached. The use of concrete with 10% silica fume has been shown to be the most effective prevention strategy against corrosion of reinforcement steel in economic terms, reducing the life cycle costs of the original deck design by 76%. From an environmental perspective, maintenance based on the hydrophobic treatment of the concrete deck surface results in the best performance, allowing for a reduction of the impacts associated with the original design by 82.8%.

Influence of Separation Interference Method on Aerodynamic Responses of a Pentagonal Shaped Bridge Deck

Long-span bridges often exhibit vibration under wind action. Various aerodynamic countermeasures have been developed over the years to enhance the aeroelastic responses of the long-span bridge deck and Separation Interference Method (SIM) is one of these. Engineers should have sound knowledge about the flow mechanism of the aerodynamic countermeasures of the bridge deck for further improvement of the aerodynamic responses and better design of the bridge deck. In the present study, a numerical investigation was carried out to disclose the flow mechanism of SIM on a pentagonal bridge deck. Simulation was conducted by using unsteady RANS for a pentagonal bridge deck with and without SIM techniques and their aerodynamic responses were compared. In the first part performance of unsteady RANS was evaluated to predict the dynamic responses for a pentagonal bridge deck. Then, the steady state responses and flow fields were explored for a bridge deck with and without SIM. Later, the dynamic responses such as flutter derivatives and unsteady pressure characteristics were evaluated and compared. It was found that SIM can improve the aerodynamic responses of the bridge deck. The addition of the curb affected the flow field around the bridge deck and the important flow features noticeably. The leading-edge top and bottom surface separations and the trailing-edge bottom surface separation are the most significant flow features to control both the steady state and dynamics responses of the bridge deck.

Bridge Abutment Movement and Approach Settlement — A Case Study and Scenario Analysis

Movement of bridge abutment is a significant issue affecting the overall reliability and safety of the structure. However, despite considerable consequences, potential movement of abutment is usually not considered in design of bridges for serviceability and abutments are generally designed as fixed elements. Theoretical analysis of bridge abutment and deck design provides background knowledge of reactions that should be anticipated and accounted for. Case studies of bridges experiencing movements and rotations show that practical outcomes often deviate from theoretical expectations. The research presented in this paper, aims to develop a better understanding of abutment stability from both a design and maintenance point of view. This paper includes an in-depth case study of the Kanahooka Road Overbridge in New South Wales, Australia. The results of a full bridge inspection leading to identification of multiple serviceability issues caused by movement of abutments are presented. Moreover, a systematic methodology is implemented, to identify potential remedial options for treatment of abutment movement. The knowledge gained through this case study has led to the development of a model for the management of abutment movement.

Design and Optimization for Ship Structure Based on Knowledge-Based Engineering

It is always pursued that the excellent ship structure is rapidly designed and modified on the premise of ensuring security in ship engineering. In this paper, design and optimization method for ship structure based on knowledge-based engineering is put forward. Combining knowledge-based engineering with parametric technology, the knowledge base of ship structure design is established and three-dimensional rapid optimal design is achieved. During the design, positions of ship structure components are driven by positional parameters. Scantlings of ship structural components are obtained by mother ships knowledge base and Non-Uniform Rational B-Splines interpolation, according to rules requirements. Main structures are optimized by quantum-behaved genetic algorithm. Examples show that this method achieves knowledge accumulation and reuse, provides design results inspection, and realizes the obtainment of reliable ship structure. 1. Introduction The ship design quality and efficiency affect ship development cycle. As ship design is a complicated process with many laborintensive activities, how to develop and modify the ship structure rapidly is a major problem for ship designers (Yang et al. 2012). Traditional ship structural design focuses on dealing with data. It is a kind of interactive graphics operation, and the results that designers work out describe only visual shape and size of ship structure, while related knowledge including design idea, expertise, parent ships information, and rules are not reflected. Obviously, it is not convenient for designers to modify and check the design model (Zhao & Kong 2005). To solve this problem, knowledge-based engineering (KBE) method is applied on ship design to integrate design methods, rules, and expertise experience into design process. Based on the related knowledge, system can automatically offer the high-qualified design model rapidly after designers input parameters and requirements. Currently, KBE is well developed in vehicle and machinery (Jin et al. 2006). However, because of the variety and complication of ship design, application of KBE on ship industry is still at the beginning. University of Rostock in Germany planned the knowledge-based system for ship modeling in research programs, which could obtain design criteria and provide tools from the knowledge base (Zimmermann & Bronsart 2007). Park identified that the expert system can significantly improve the efficiency and quality of the ship design, and integrated design knowledge into design system and achieved a highly flexible design environment (Park & Storch 2002). Lee applied KBE to the general arrangement of the engine room, making full use of engineering knowledge data (Lee & Yeun 2006). Wu proposed knowledge-based modeling for ship overall design to achieve information storage and retrieval (Wu & Shaw 2011). Chen applied KBE on ship deck design (Chen et al. 2010). Cui used KBE on midship section structural design (Cui et al. 2012). Cai developed a midship section design system based on AutoCAD, subdivided transverse section into several modules, and obtained the min-area midship section (Cai et al. 1997).

Field measurement and practical design of a lightweight composite bridge deck

Ultrahigh-performance concrete (UHPC) layers play an important role in steel-UHPC lightweight composite bridge decks. To characterize the contribution of the UHPC layer to these decks, field measurements were conducted, and the strain responses of various detail categories were measured for orthotropic steel decks with and without UHPC layers. The results show that the UHPC layer influences the stress range of the various detail categories significantly. ANSYS software was also applied to model the lightweight composite bridge deck, and a transient analysis was performed to investigate the influence of the vehicle speeds. Finally, the influence surfaces of the detail categories were introduced to determine the variation of the stress range, and a simple method was proposed to design the UHPC layer.

Flexible decision analysis procedures for optimizing the sustainability of ageing infrastructure under climate change

Currently, there is significant interest in ensuring the sustainability and serviceability of infrastructure systems in the context of climate change. Indeed, a large proportion of existing structures already are in an advanced state of deterioration, thus affecting the sustainability and usefulness of these structures, and highlighting the need for better planning and decision analysis tools. Such tools would benefit from improved models to predict the residual life of structures, to estimate benefits derived from infrastructures, to account for uncertainties associated with physical and financial processes, and to provide more flexibility in decision-making strategies. These concepts are investigated through application of a risk-based decision-making model for reinforced concrete bridge decks in Montreal to estimate the optimal timing for deck repairs. A probabilistic deterioration model is used to predict the residual life of concrete decks as a function of exposure to de-icing salts using historical data and predictions from climate change scenarios. Historical data are used to validate model assumptions by comparing predicted condition states to observations from periodic inspections, while the climate scenarios are used to evaluate the impact of climate change on deterioration rates assuming that current deck design and de-icing salt management strategies are not modified. In this instance, the optimal timing for the first major repair is influenced by the uncertainty involved with climate change predictions and the future availability of funds, while ensuring the safety of users and the required level of service. The proposed framework, based on a cost-benefit analysis, is applicable to any infrastructure project.

Comparison of anthropometry of Brazilian and US Military population for flight deck design

A valid anthropometric dataset is essential to optimize the design of personal equipment and aircrafts. Until recently there were no anthropometric data available for the Brazilian Air Force (FAB) pilot population, and hence international military data have often been used in Defense procurement specifications. Currently, the Brazilian Aeronautical Industry is designing military aircraft using legacy U.S. military anthropometric data. Some accommodation problems have been identified among FAB pilots, highlighting the necessity to investigate this possible issue.The anthropometric data of the six critical body measurements indicative of cockpit design from the U.S military legacy databases were compared one at a time to the FAB corresponding anthropometric data in three ways: F-test, t-test, and 5th - 95th percentile limits. This study aimed to verify whether the U.S. Military Personnel legacy databases are applicable to the Brazilian pilot population for aircraft cockpit design purpose.Brazilian pilots were significantly (p < 0.05) different in body size when compared to the U.S. military personnel in legacy databases. The dimension that differ the most was Thumbtip Reach, demonstrating a difference in body proportion beyond that illustrated by the difference in body size.The reported anthropometric analyses can be used as relevant consideration in product, workplaces, and system design. The U.S. legacy databases were considered inappropriate for ergonomic cockpit design for the Brazilian Air Force pilots.Relevance to industry: When designing complex workplaces, systems, and personal protective devices, designers and ergonomists should use anthropometric data from a sample population that represents the body size variation expected in the target population. The anthropometric comparisons presented in this study are useful to design an ergonomic flight deck layout for both genders.

Influence of the welding process on the residual welding stresses in an orthotropic steel bridge deck

An orthotropic steel bridge deck consists out of a number of longitudinal and transverse stiffeners. These stiffeners are welded to the deck plate which cause residual stresses to be present near the vicinity of this connection. In addition, the welding operation causes multiple fatigue problems across the bridge deck which lead to the formation of fatigue cracks. For an accurate fatigue design of an orthotropic bridge deck, the residual stresses should also be taken into account to determine the effect of these stresses with respect to the load-induced stresses. Tensile residual stresses should be avoided since they tend to open fatigue cracks which results in a shorter fatigue life. The welding of the longitudinal stiffener to the bridge deck plate is simulated with finite element modelling. The effect of the size of the tack welds, the welding current and the welding speed on the residual stresses is determined. These different welding sequences are modelled in order to minimize tensile residual stresses near the weld connection. The welding configuration which leads to smaller tensile residual stresses will result in an orthotropic steel bridge deck with a longer fatigue lifetime.

Anesthesia Medication Handling Needs a New Vision.

Anesthesia Medication Handling Needs a New Vision.

Shear lag effects on wide U-section pre-stressed concrete light rail bridges

Recently, U-section decks have been more and more used in metro and light rail bridges as an innovative concept in bridge deck design and a successful alternative to conventional box girders because of their potential advantages. U-section may be viewed as a single vent box girder eliminating the top slab connecting the webs, with the moving vehicles travelling on the lower deck. U-section bridges thus solve many problems like limited vertical clearance underneath the bridge lowest point, besides providing built-in noise barriers. Beam theory in mechanics assumes that plane section remains plane after bending, but it was found that shearing forces produce shear deformations and the plane section does not remain plane. This phenomenon leads to distortion of the cross section. For a box or a U section, this distortion makes the central part of the slab lagging behind those parts closer to the webs and this is known as shear lag effect. A sample real-world double-track U-section metro bridge is modelled in this paper using a commercial finite element analysis program and is analysed under various loading conditions and for different geometric variations. The three-dimensional finite element analysis is used to demonstrate variations in the transverse bending moments in the deck as well as variations in the longitudinal normal stresses induced in the cross section along the U-girder\'s span thus capturing warping and shear lag effects which are then compared to the stresses calculated using conventional beam theory. This comparison is performed not only to locate the distortion, warping and shear lag effects typically induced in U-section bridges but also to assess the main parameters influencing them the most.

Finite Element Analysis of Ship Deck Sandwich Panel

Recently various types of sandwich panel are applied for constructing bridge and ship structures. Sandwich panel is material that consists of lightweight core material and two metal faceplates. The application of sandwich panel in ship structures makes the structure less-complex and ship’s selfweight lighter because of the reduction of secondary stiffeners. This paper discusses sandwich panel that was fabricated using synthetic resin core material and two steel faceplates. This study is aimed to analyze stresses developed in the sandwich panel of 750 GT Ro-Ro ship car deck structure when it was subjected to the deck design load. The finite element analysis was carried out to obtain the stress distribution and maximum deformation on the car deck structures. The stress of the ship car deck constructed using conventional steel structure, i.e. steel plate and stiffener, was compared with the stress of the deck that was built using sandwich panel.

FEATURES OF DESIGN OF TIED-ARCH BRIDGES WITH FLEXIBLE INCLINED SUSPENSION HANGERS

Purpose. Investigation and analysis of the hanger arrangement and the structural stability of a Network arch bridge – a tied-arch bridge with inclined hangers that cross each other at least twice. It is also necessary to make a comparative analysis with other types of hanger arrangements. Methodology. The authors in their research investigated a large number of parameters to determine their influence in the force distribution in the arch. Eventually they determined optimal values for all parameters. These optimal values allowed developing a design guide that leads to optimal arch design. When solving this problem, the authors used three-dimensional finite element models and the objective was to determine the most suitable solution for a road bridge, with a span of 100 meters, consisting of two inclined steel arches, located on a road with two traffic lanes, subjected to medium traffic. The virtual prototype of the model is performed by finite element simulator Midas Civil. Findings. In this study, for the bridge deck, a concrete tie appears to be the best solution considering the structural behavior of network arches, but economic advantages caused by easier erection may lead to steel or a composite bridge deck as better alternatives. Design requirements and local conditions of each particular bridge project will decide the most economic deck design.Originality. To ensure passenger comfort and the stability and continuity of the track, deformations of bridges are constricted. A network arch is a stiff structure with small deflections and therefore suitable to comply with such demands even for high speed railway traffic. A network arch bridge with a concrete tie usually saves more than half the steel required for tied arches with vertical hangers and concrete ties. Practical value. Following the study design advice given in this article leads to savings of about 60 % of structural steel compared with conventional tied arch bridges with vertical hangers.

Load Distribution Factors for Composite Multicell Box Girder Bridges

Cellular steel section composite with a concrete deck is one of the most suitable superstructures in resisting torsional and warping effects induced by highway loading. This type of structure has inherently created new design problems for engineers in estimating its load distribution when subjected to moving vehicles. Indian Codes of Practice does not provide any specific guidelines for the design of straight composite concrete deck–steel multi-cell bridges. To meet the practical requirements arising during the design process, a simple design method is needed for straight composite multi-cell bridges in the form of load distribution factors for moment and shear. This work presents load distribution characteristics of straight composite multi-cell box girder bridges under IRC trains of loads.

09.04: Fatigue behaviour of the closed rib to deck and crossbeam joint in a newly designed orthotropic bridge deck

ABSTRACTOrthotropic decks are widely used in large span and movable steel bridges and the design is dominated by fatigue resistance. Closed rib to deck welded joints in the orthotropic decks are sensitive to fatigue loads and a number of fatigue cracks are reported in bridge inspections. For the design of new bridge decks, thicker deck plates are proposed for reducing stresses in fatigue sensitive locations like the conjunction of the deck plate, rib and crossbeam. Compared to the joints in span, the variation of stress at the crossbeam is larger due to the high stress concentration near the weld root. In this study, fatigue tests are carried out on a full‐scale orthotropic deck segment to study the initiation and propagation of fatigue cracks in the deck plate. Trapezoidal stiffeners are welded to a 20 mm thick deck plate and different welding methods are used in manufacturing the specimen. Various load levels are applied on the deck plate by hydraulic jacks. The strain gauges are attached both at the top and bottom of the deck plate in the vicinity of the expected crack paths. The strain history and distribution of strain ranges at the characteristic sections are analysed. An ultrasonic method, time‐of‐flight diffraction, is used to inspect the sizes of the cracks after testing. Comparison of the number of cycles that corresponds to a crack propagation is given in the hot spot S‐N curve figure. With a failure criterion of 10% strain range deviation, the fatigue strength scatter of the 20 mm thick deck plate is similar to that of the 12 mm deck.

21.02: Strengthening of orthotropic steel decks using UHPC: UHPC‐concrete instead of asphalt layer for additional at least 50 years in service

ABSTRACTOrthotropic steel bridge decks for slender and long spanned girder bridges were frequently built in the 60ties and 70ties of the last century in Europe. In the design of such bridge decks only the ultimate load carrying capacity was considered, without fatigue aspects. Due to the dramatic increase of heavy traffic in the European road network, sometimes the calculated remaining fatigue life is exhausted, after only 50 years of service life.In the paper the relevant results of a research project are presented, with the challenging aim to increase the service life of such orthotropic bridge decks to at least 50 years after strengthening. The research activities were based on a very slender orthotropic deck, with a slenderness of elr/tdp = 36 for the deck plate. Two significant details for fatigue of such a representative bridge deck have been analysed. Detail D1 represents the welded connection of the longitudinal rib to the deck plate and Detail D2 is the welded connection of the longitudinal rib to the cross girder. Extensive numerical studies were done for the strengthening solution with an UHPC‐concrete layer. First the present remaining service life was calculated using a finite element model of the steel deck. The beneficial effect of the asphalt layer is considered by an increased wheel contact area. The current fatigue load model FLM‐4 from the Eurocode with 5 lorry types and 3 different axle types was executed and the gross weight of each lorry type was adapted to weigh in motion measurements at an Austrian highway bridge. For determining the stress reduction factors in the details D1 and D2 after strengthening the finite element model had to be extended with the UHPC‐concrete layer. The concrete cracking was conservatively considered with an effective Young modulus Ec,eff = Ec/4. For both details at least 50 years in service can be guaranteed with an UHPC‐pavement that has a thickness of 80mm. Based on these studies full scale tests on an orthotropic deck specimen were done, including overload effects (increased axle loads) and severe temperature effects (simulation of a cold rain event on a very hot summer day) to stimulate concrete cracking. The full scale tests together with the numerical studies showed very good results with regard to the remaining fatigue life. Therefore in the near future a prototype application on an Austrian highway bridge is intended.

00.06: Advances and development needs in the structural design of steel box girders for major bridges

ABSTRACTMajor cable‐supported bridges with a span exceeding 600m would not normally be feasible without a steel box girder to carry the traffic load. These box girders generally comprise a structural steel deck plate stiffened longitudinally by open or closed ribs and transversely by diaphragms. The stiffened deck plate supports the local wheel load and distributes it to the diaphragms from where it is transferred into the box girder. The stiffening ribs also increase the total cross‐sectional steel area and thereby contribute to the overall bending capacity of the box girder and finally, the stiffeners increase the resistance of the plate to buckling.This type of deck structure is generally called an “orthotropic bridge deck” due to the orthogonal nature of the stiffened deck plate and was first developed and utilised in 1950. The orthotropic steel deck is considerably lighter than a concrete slab in a composite girder and therefore makes longer span bridges possible, by reducing the self‐weight forces that would otherwise dominate. The self‐weight of the girder is a key driver in major bridge designs since it must be carried by all other bridge components, such as cables, towers, anchorages and foundations. The orthotropic steel girder is usually a fully closed box girder with all stiffening ribs placed inside the girder giving a smooth outer surface that is easy to paint and maintain. The interior of the closed box is often dehumidified without being painted giving an environmentally‐friendly fabrication that is safe to operate and maintain.However, the orthotropic steel deck is highly prone to fatigue meaning that the number of passing lorries, their axle/wheel configuration and total vehicle weight have a significant impact on the bridge deck design and fatigue life. The orthotropic deck therefore has higher fabrication costs when compared to conventional steel structures due to the high‐quality steel manufacturing and welding procedures that are necessary to achieve the required fatigue performance.The overall layout of an orthotropic bridge deck is basically unchanged since the 1960s, however the detailing has been refined considerably to a level where it is now seems difficult to improve it much further. However, the introduction of new materials e.g. sandwich steel deck structures in combination with new welding or gluing techniques could push box girder designs to new heights.

Kinase Crystal Miner: A Powerful Approach to Repurposing 3D Hinge Binding Fragments and Its Application to Finding Novel Bruton Tyrosine Kinase Inhibitors

Protein kinases represent an important target class for drug discovery because of their role in signaling pathways involved in disease areas such as oncology and immunology. A key element of many ATP-competitive kinase inhibitors is their hinge-binding motif. Here, we describe Kinase Crystal Miner (KCM)-a new approach developed at Boehringer Ingelheim (BI) that harvests the existing crystallographic information on kinase-inhibitor co-crystal structures from internal and external databases. About 1000 unique three-dimensional kinase inhibitor hinge binding motifs have been extracted from structures covering more than 180 different protein kinases. These hinge binding motifs along with their attachment vectors have been combined in the KCM for the purpose of scaffold hopping, kinase screening deck design, and interactive structure-based design. Prospective scaffold hopping using the KCM identified two potent and selective Bruton tyrosine kinase (BTK) inhibitors with hinge binding fragments novel to BTK.

Biocomposite Bridge

Biocomposite materials are becoming more interesting to use in infrastructural projects due to their biodegradable, renewable, recyclable and sustainable properties. With a relatively low density, it is an interesting building material regarding a bridge deck. When designing with biocomposite the following factors are important to consider: material design, fibre treatment, coating and manufacturing technique. A PLA-Bamboo biocomposite was applied to an existing design of a bridge deck made out of synthetic composite. Due to its randomly oriented fibres and its equally designed lamellae, the cross section was considered homogeneous and the stresses were calculated according to ‘Hooke’s law’. The unity checks were performed according to ‘CUR 96’ with an own devised material factor of 5,69. This factor was calculated in this study for biocomposites with untreated fibres. The calculations showed that the original material (synthetic composite) was not directly replaceable by the PLA-Bamboo biocomposite. An alternative design of the deck (deck height of 1 meter and doubled thicknesses of the skins and web plates, 40- and 10 mm) showed better results. This design complied for the unity checks for strength.

Coupled Fatigue-Corrosion Failure Analysis and Performance Assessment of RC Bridge Deck Slabs

Coupled fatigue and corrosion is more detrimental for RC bridge deck slabs than either fatigue or corrosion separately. The main objectives of this study are to obtain a greater understanding of the deterioration mechanisms and failure modes of RC bridge deck slabs subjected to coupled fatigue and corrosion. Analysis of the joint interaction between chloride-induced steel corrosion and fatigue cracking of concrete is presented. Moreover, the effects of fatigue cracking on the chloride diffusion process and the influences of internal forces redistribution caused steel corrosion on the reinforcement-fatigue stress range were studied. On the basis of the coupled fatigue-corrosion damage mechanism, two fracture-failure modes of concrete bridge decks were proposed and the corresponding limit state functions were deduced. Finally, the performance assessment of an illustrative example shows that the coupled fatigue-corrosion effects obviously reduced the fatigue life of RC bridge deck slabs. It was concluded that the effects of coupled fatigue and corrosion should not be neglected in the fatigue safety design of RC bridge decks.