Deck Design Research Articles

Artificial Neural Network and Kriging Surrogate Model for Embodied Energy Optimization of Prestressed Slab Bridges

The main objective of this study is to assess and contrast the efficacy of distinct spatial prediction methods in a simulation aimed at optimizing the embodied energy during the construction of prestressed slab bridge decks. A literature review and cross-sectional analysis have identified crucial design parameters that directly affect the design and construction of bridge decks. This analysis determines the critical design variables to improve the deck’s energy efficiency, providing practical guidance for engineers and professionals in the field. The methods analyzed in this study are ordinary Kriging and a multilayer perceptron neural network. The methodology involves analyzing the predictive performance of both models through error analysis and assessing their ability to identify local optima on the response surface. The results show that both models generally overestimate the observed values. The Kriging model with second-order polynomials yields a 4% relative error at the local optimum, while the neural network achieves lower root mean square errors (RMSEs). Neither the Kriging model nor the neural network provides precise predictions but point to promising solution regions. Optimizing the response surface to find a local minimum is crucial. High slenderness ratios (around 1/28) and 40 MPa concrete grade are recommended to improve energy efficiency.

Vibrational analysis of polyurethane-sandwiched bridge decks with variable skew angles

Bridge decks are the surface of bridges that carry the weight of the vehicles and pedestrians crossing over them. The design of bridge decks varies depending on the span, traffic volume, and material availability. But nowadays, the need for a sustainable approach is required. So, use of a sustainable material for construction and retrofitting purposes is the need of the hour. In the present study, a novel synthetic material polyurethane has been used in bridges. The study deals with the variation in skew angles to determine the response of the bridge deck. The response of natural frequencies on the bridge deck due to the variation in skewness and thickness of steel are analysed under simply supported and clamped boundary conditions. Further, the bridge deck is sandwiched using steel and polyurethane having different thicknesses, and the responses are recorded. Afterwards, a bridge deck is modelled using polyurethane as a special case, to pursue sustainability and justify the RRR (reduce, reuse, and recycle) concept of waste management. A comparative study is also performed between the isotropic steel deck and sandwiched deck by varying the skewness. The skew angle is varied from 0° to 60° with a difference of 10°, i.e., 0°, 10°, 20°, 30°, 40°, 50°, and 60°. The frequencies of the isotropic steel and sandwiched decks are increasing when the skewness is increased. Also, the decks may be modelled in a way to enhances the vibration behaviour by sandwiching the existing steel decks. The free vibration frequencies of the sandwiched decks are comparable to the steel deck of similar thickness, which shows the use of polyurethane as the core material does not affect the vibrational characteristics of the deck, while at the same time reducing the cost significantly. The research lays the groundwork for the creation of engineering recommendations that practitioners can use.

Visual Attention Distribution of Pilot Flying vs. Pilot Monitoring During Different Flight Phases

With the continuous maturation of technology and the deepening of human-centered design philosophy, eye tracking technology has gradually been applied in research studies for the optimization of flight deck design in commercial aviation. While these studies have focused solely on Pilot Flying (PF), without considering the visual attention distribution of Pilot Monitoring (PM). The purpose of this study was to analyze and compare the visual attention distribution of PF and PM during different flight phases, providing more comprehensive guidance and optimization suggestion to the flight deck design in commercial aviation. This study was conducted in the A320 full-motion flight simulator, with eye tracking technology recording eye movements of PF and PM in the same flight crew simultaneously. The result showed significant differences in three eye movement metrics between PF and PM, not only throughout the whole common manual circuit but also within specific flight phases. Additionally, the results indicated that in certain flight phases, PF and PM exhibited statistically significant correlations in certain eye movement metrics for specific areas of the flight deck. However, in most other instances, no statistically significant correlations were observed between the eye movement metrics of PF and PM. Therefore, the future design of flight decks may benefit from considering differentiation between PF and PM sides in certain flight phases or areas. Additionally, it can be beneficial to make dynamic adjustments to the current flight deck display and control interface while maintaining the existing layout design.

Experimental and numerical study on honeycomb T-beam bridge deck

The inefficiency in the construction of intermediate diaphragms for T-beam bridges (referred to as conventional T-beam), has long been a significant research concern. This study focuses on a novel bridge deck design (referred to as honeycomb T-beam), which effectively eliminates the need for intermediate diaphragms, thus enhancing construction efficiency. Segment models of both conventional T-beam and honeycomb T-beam were designed and fabricated, and their transverse mechanical performance was compared through transverse static tests. Additionally, numerical simulations using ABAQUS were conducted and validated with experimental data. Based on the numerical model of honeycomb T-beam, crack width calculation and reinforcement optimization were performed. The main conclusions are as follows: (1) The design of honeycomb T-beam allows for less reinforcement, making it more economical while ensuring that the bearing capacity reaches the same level. (2) Honeycomb T-beam exhibits superior durability and bearing capacity, with a failure mode that is more ductile. (3) The results of numerical simulation highly coincide with experimental results. Besides, this paper proposes and validates a practical method for crack width calculation. (4) Parametric analysis show that increasing the reinforcement area at right inner hole of honeycomb T-beam by 10% can enhance the bearing capacity by 18%. Based on this, design suggestions are made for honeycomb T-beams and other perforated structures.

Fatigue behavior and damage mechanism of steel plate-UHPC composite bridge deck subjected to negative bending moment

In order to investigate the fatigue behavior and failure mechanism of steel plate-UHPC composite bridge deck under hogging moment, a total of four full-scale specimens with two class of reinforcement ratio (Three specimens with reinforcement ratio of 1.58 %, 1.69 %, 1.86 %, respectively, which called longitudinal specimen. One specimen with reinforcement ratio of 0.89 %, which called transverse specimen.) were designed and tested under fatigue loading. Test results reveal that when the fatigue loading ratio was 0.25 with maximum load of 0.8 times of the static cracking load, taking the crack width of 0.10 mm as the fatigue failure criterion, the fatigue life of longitudinal specimen over 16 million cycles. However, the fatigue life of transverse specimen was only 9.08 million cycles. The longitudinal reinforcement restricts the propagation of fatigue cracks along the depth of the UHPC slab, and tensile fracture of the steel fibers occurred in the region between the top layer of longitudinal reinforcement and the UHPC surface. The fatigue damage mechanism resulting from fatigue degradation of the UHPC layer in the tension zone is identified. In addition, The fatigue design of the steel plate-UHPC composite bridge deck should be controlled by the durability rather than the strength. The established tensile S-N curve with 0.05 mm critical UHPC crack width could be used evaluate the fatigue cracking resistance of composite bridge deck.

The Impact of Various Cockpit Display Interfaces on Novice Pilots' Mental Workload and Situational Awareness: A Comparative Study.

Future airspace is expected to become more congested with additional in-service cargo and commercial flights. Pilots will face additional burdens in such an environment, given the increasing number of factors that they must simultaneously consider while completing their work activities. Therefore, care and attention must be paid to the mental workload (MWL) experienced by operating pilots. If left unaddressed, a state of mental overload could affect the pilot's ability to complete his or her work activities in a safe and correct manner. This study examines the impact of two different cockpit display interfaces (CDIs), the Steam Gauge panel and the G1000 Glass panel, on novice pilots' MWL and situational awareness (SA) in a flight simulator-based setting. A combination of objective (EEG and HRV) and subjective (NASA-TLX) assessments is used to assess novice pilots' cognitive states during this study. Our results indicate that the gauge design of the CDI affects novice pilots' SA and MWL, with the G1000 Glass panel being more effective in reducing the MWL and improving SA compared with the Steam Gauge panel. The results of this study have implications for the design of future flight deck interfaces and the training of future pilots.

Future flight deck design: Developing an innovative touchscreen inceptor combined with the primary flight display

The touchscreen has the potential to optimize the space usage and efficiency of the flight deck. Currently, touchscreens can combine the input and output functions of different systems. However, it does not yet serve as an inceptor to replace the sidestick or control column for aircraft manoeuvres. This study aims to examine the potential of a touchscreen as a flight inceptor compared with a traditional sidestick and gamepad. This research recruited 72 participants who interacted with three inceptors for both an instrument landing with disturbance and without disturbance using the Future System Simulator. The findings demonstrated that pilot performance, system usability and pilots’ situation awareness of touchscreen inceptors were significantly inferior to those of traditional sidesticks and gamepads. Compared to the sidestick and gamepad, the touchscreen provided a poorer situation awareness with the highest supply and demand. In addition, the performance of all inceptors was significantly influenced by disturbance. There is still a long way to go for certification of a touchscreen as an inceptor on the future flight deck. This research showed that even though the touchscreen inceptor scored the lowest on both SUS and SART, the majority of pilots agreed that the touchscreen inceptor provided a better attentional supply in challenging disturbance circumstances, providing proof of concept for its possible inclusion in flight deck design. There is a potential that the emerging touchscreen as an inceptor may develop further along with human-system integration flight deck design.

Structural design and lifecycle analysis of an orthotropic steel deck bascule bridge

This study presents the structural design and lifecycle analysis of an orthotropic steel deck (OSD) bascule bridge in Viareggio (Italy), considering various operational states and constraints. The analysis varied the bridge’s opening angle in 15-degree increments from 0 to 90 degrees, using two steel grades, S355 and S450, by comparing hydraulic or electro-mechanically driven activation mechanisms. The findings reveal that as the static model transitions from pinned-pinned to cantilevered when the bridge is opened, the structural demand for bending moment and shear force increases, with a maximum of nearly 15°–30°. At the same time, axial forces shift from tensile to compressive. Structural design has been carried out using higher grade steel (S450), which has led to a 17.17% mass reduction, cost savings of 3.4%, and a notable decrease in CO2 emissions by 16%. This proves that despite using higher-grade steel characterized by more significant CO2 emissions, the mass reduction associated with the refined design leads to an overall lower environmental footprint. This fact underscores the importance of selecting proper steel grades for steel to achieve an optimal trade-off between CO2 emissions and mass reduction.

A Real-Time Measurement Model of Attention-Allocation Level and Its Application in Simulated SPO Task

Most human-caused flight accidents can be attributed to a pilot’s attention deficit and monitoring errors. Accordingly, pilots’ attention allocation is strongly related to their task performance. This study is aimed at analyzing pilots’ fixation characteristics and attention-allocation levels. First, we proposed a model for measuring attention-allocation level based on the salience, effort, expectancy, and value (SEEV) model. Second, a low-fidelity single-pilot operation (SPO) cockpit environment was constructed, and 20 pilots were recruited for an experiment to compare their fixation characteristics between SPO and double-pilot operation (DPO) scenarios. The results showed slight differences in the attention levels allocated by SPO and DPO pilots under a scenario of one-engine failure. It concluded that Human-centered flight deck design can enhance a pilot’s attention allocation level. These findings can be used to optimize future flight deck designing and flight training for improving pilot’s task performance.

Study on biaxial bending fatigue performance of Engineered Cementitious Composites (ECC)

Structural components such as bridge deck, highway pavement and thin-walled roof dome often are subjected to the biaxial and even multi-axis stress state due to the external load. Also, the fatigue effect cannot be ignored due to the moving vehicle load in the design of these structures. If engineering cementitious composites (ECC) is used in the above traditional concrete structures, their performance, such as easy cracking and short service life can be greatly improved. However, the biaxial bending fatigue performance of ECC should be analyzed in detail. At present, the biaxial bending test methods of cement-based materials include biaxial bending test (BFT) and centrally loaded round panel test (RPT). This study used both RPT and BFT test methods to analyze the biaxial fatigue performance of ECC and used four-point bending test (4PBT) uniaxial fatigue test as a reference. The stress levels S were set as 0.5, 0.6 and 0.7. The uniaxial and biaxial bending fatigue failure procedures of ECC were analyzed by plotting the three-stage deflection development curve, the fatigue damage and strain relationship curve based on the linear cumulative fatigue damage theory, and the S–N curve. The fatigue life of ECC biaxial bending specimens was greater than that of uniaxial bending specimens. At S = 0.5, the fatigue life: BFT > RPT. At S = 0.6, the fatigue life of BFT and RPT specimens was close. At S = 0.7, the fatigue life: BFT < RPT. With increasing stress level, the fatigue life of BFT specimen decreases more than that of RPT specimen. The lognormal distribution model and Weibull distribution model were used to fit the uniaxial and biaxial bending fatigue life of ECC, respsectively. Using the double logarithmic fatigue equation, fatigue life under the failure probability PF of 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 was derived. The survival rate represents the level of safety reservation, which could provide reference and basis for the design of ECC bridge deck and highway pavement with different safety reservation requirements.

Influence of chloride-induced corrosion on the traffic vulnerability of simply supported Italian PC bridges: a preliminary study

In Italy, a large part of road bridges was built after the Second World War, mainly with Reinforced Concrete (RC) or Prestressed Concrete (PC) simply supported decks. Most of the bridges currently in service have been designed with outdated codes and could be inadequate to modern heavy traffic loads. Furthermore, their structural performance decrease over time due to ageing effects, like steel corrosion.Bridges are often exposed to chlorides from de-icing salts or marine environment; chloride diffusion in concrete can induce pitting corrosion of steel reinforcing, decreasing the structural resistance of bridge elements. As part of a broader study on the structural risk of existing bridges with respect to traffic loads, it is certainly of interest to investigate the influence of chloride-induced corrosion on the risk itself.In this preliminary study, four sets of simply supported decks made of precast PC beams and a cast in-situ RC slab were designed according to outdated Italian codes relating to different construction periods (60s, 70s, 80s, and 90s); each set is composed by bridges with different span, width, number of main girders and transverse diaphragms. The deck design took into account only the bending failure of the main girders, in order to determine the minimum amount of strands and steel reinforcements required. The vulnerability to traffic loads is evaluated with respect to the bending moment resistance of the main girders. Monte Carlo simulations were performed to evaluate the decrease over time of the resisting bending moment of the main girders, taking into account literature models for estimating the time to corrosion and corrosion propagation both in strands and in steel reinforcements.

An evolutionary approach to developing supporting software for the design of card deck-based mathematical didactic games

Didactic card games have demonstrated their efficacy in engaging Generation Z students in diverse course materials in the field of natural sciences. However, the absence of suitable tools poses a significant obstacle to the creation of card decks which include complex formulas. In this paper, we introduce a JavaScript-based web application that simplifies and accelerates the design process by providing support for LaTeX that enables the integration of scientific equations onto the cards. The proposed software aims to encourage educators to participate in card deck design, with the ultimate goal of contributing to the broader adoption of scientific card games.

Shaping bridge decks for VIV mitigation: A wind tunnel data-driven adaptive surrogate-based optimization method

Vortex-induced vibration (VIV) of deck girders frequently drives the wind-resistant design of wind-sensitive bridges from the preliminary to final design stages. Shaping bridge decks is a proven strategy to mitigate VIV. While significant shape modifications are commonly restricted to preliminary design stages, only minor medications are possible at advanced design stages, typically involving adding flow modifiers or changing the shape and location of existing appendages. These mitigation strategies have been implemented in the last decades by carrying out expensive wind tunnel campaigns and following heuristic design rules. This paper proposes an experimental data-driven adaptive surrogate-based optimization approach to systematically identify optimum deck shapes that minimizes the economic cost of the bridge while fulfilling the VIV project specifications. The methodology is conceived to carry out simultaneously the general and detailed shape design of the final deck configuration by harnessing a sequential sampling plan aiming at reducing the sectional model construction costs. The proposed holistic design framework is successfully applied to a real application case involving 26 wind tunnel tests of 1.8-meter wide sectional models to figure out the optimal gap distance and location of maintenance tracks of a twin-box deck equipped with all the appendages included in the final deck design.

Materials, Structure, and construction of a low-shrinkage UHPC overlay on concrete bridge deck

As ultra-high performance concrete (UHPC) has superior mechanical and durability properties, it is a promising solution to apply a thin layer of UHPC on top of normal concrete bridge decks to extend the service life and enhance the structure integrity. However, the large autogenous shrinkage characteristics of UHPC is still an issue, and there is a lack of research focus on the structural design and stress analysis of the concrete bridge deck and UHPC overlay system. Thus, this study first designs and evaluates a new low-shrinkage UHPC mixture internally cured with a high-strength, high-abrasion resistant, and porous aggregate (calcined bauxite, CB), and the optical mixture design is validated by testing the fresh, mechanical, autogenous shrinkage, abrasion, and impact properties of the UHPCs. Second, the outdoor UHPC overlay-NC composite slab experiments and the numerical modeling are carried out to analyze the shrinkage performance of the UHPC, debonding potential of the overlay layer, stress and strains development in the system. Then, the significant influencing factors and the key measures to assure the UHPC-NC interface bonding properties are obtained, including proposing a grouped L-shape steel rebar arrangement for strengthening the interface. Finally, the applicability of the new low-shrinkage UHPC mixture as overlay materials on a real concrete bridge deck is demonstrated. Based on these, the engineering design scheme and the construction recommendations of an environmentally-cured low-shrinkage UHPC overlay on concrete bridge deck is given. The utilization of UHPC overlay on concrete bridge decks offers a novel paving system that substantially enhances strength, abrasion resistance, and durability.

Flight Deck Simulation of Complex Clearance Information Entry During Relative Spacing Arrival Operations

Interval management (IM) uses Automatic Dependent Surveillance–Broadcast to provide greater air traffic system throughput and efficiency by improving inter-aircraft spacing precision. The IM Dependent Staggered Approach (DSA) application enables aircraft within a pair to achieve a spacing objective when arriving to parallel, dependently scheduled runways. These operations may require lengthier or more complex IM clearance communications that, coupled with manual entry of ownship route information and forecast winds, can result in a more challenging setup task than has been previously examined. An experiment with 16 pilots was conducted to examine the flight crew acceptability, feasibility, and technical assumptions related to conducting IM DSA operations in a metering environment with voice communications. Results show flight crew errors during entry of the clearance elements into the Cockpit Display of Traffic Information traffic display, especially with a long and highly complex IM clearance. The manual entry of ownship route and forecast wind information also appeared to increase the complexity of the entry task and the potential for errors. Recommendations are made to the Federal Aviation Administration and equipment manufacturers regarding IM communications and the design of related flight deck displays to avoid entry errors and, when they occur, indicate the source to pilots.

Experimental study on optimization of continuous steel box girder bridge deck

ABSTRACT In order to accurately optimize the structural parameters of steel bridge deck(OSD), an optimal design method of continuous steel box girder bridge deck based on response surface method is proposed. Optimization design process includes full scale model test, finite element analysis, response surface function fitting and design parameter optimization. The orthotropic steel bridge deck’s deck thickness, stiffener thickness, diaphragm thickness, stiffener height, and diaphragm opening form are chosen as independent variables, and the internal forces of important structural components discovered are used as dependent variables. Design-Expert software created a five-factor, three-level response surface test. A multivariate quadratic response surface regression model between structural parameters and target response values was developed after the objective function and constraint criteria were identified. Numerical theory’s variance analysis was used to find the best combination, and Design Expert software was used to confirm it to make sure the design value was accurate. The findings indicate that optimized structural parameters are trustworthy because the difference between the predicted value and the theoretical value is less than 5%. An orthotropic steel bridge deck’s structural parameters can be optimized using the response surface approach. It serves as a reference for subsequent steel bridge deck design and construction.

Study on Shear Resistance and Structural Performance of Corrugated Steel–Concrete Composite Deck

This study looks into a new composite bridge deck structure that employs a corrugated steel plate as the base. The goal is to address the shortcomings of traditional deck-bearing capacity, stiffness, and stress performance. Specifically, this study investigates the shear performance and slip characteristics of this structure. To achieve this, the study analyzes the shear behavior and slip tendencies of the composite bridge deck. The study focuses on the role of shear studs and PBL (Perfobond Leiste) perforated steel plates as essential components for shear connections. The shear performance of the composite deck is analyzed based on the structure of shear connection keys such as shear studs and PBL perforated steel plates. The advantages of composite decks in terms of stiffness, self-weight, load-bearing capacity, shear resistance, slip resistance, etc., are discussed to provide a theoretical reference for practical engineering applications. The shear resistance of shear stud shear keys is investigated through shear push-out experiments, and the shear resistance of shear studs is investigated through finite element simulations based on the ABAQUS 2020 finite element software. The results showed that the shear load capacity of the shear studs increased with the increase in the height-to-diameter ratio for different diameters of the shear studs, and the range of increases was from 2% to 23%. However, when the diameter of the shear stud exceeded 22 mm, the ultimate shear capacity of the shear stud increased with the increase in the height-to-diameter ratio, and the magnitude of the increase slowed down. For the actual design of the composite deck, it is recommended to maintain a shear stud height-to-diameter ratio within the range of 9 to 12. When using a composite deck with a PBL open-hole steel plate, the maximum longitudinal slip at the plate end and within the span is only 0.28 mm and 0.0158 mm, respectively. These values are 31% and 36% lower than those of the composite deck with a peg shear key. Additionally, the vertical peeling within the span of the PBL open-hole steel plate is merely 0.46 mm, showing a 21% reduction compared to that of the shear studs. It can be seen that the PBL perforated steel plates are more effective than the shear studs in resisting slip and peel.

Fatigue verification of orthotropic bridge decks with the hot‐spot method – Background to TS 1993‐1‐901

AbstractThe design of orthotropic bridge decks (OBD) is driven by fatigue. The Eurocode on fatigue of steel structures – prEN 1993‐1‐9:2023 – provides fatigue resistance (S‐N) curves for relevant details in OBD. These curves are to be used with the far field (nominal) stress. However, due to the complex geometry and loading of OBD, the nominal stress is not well defined for many details. In addition, cracks have been found in practice in OBD at locations for which S‐N curves are not provided. In order to overcome these issues, experimental and numerical studies are carried out on the use of local stresses (hot‐spot stresses where possible) for the fatigue design of OBD. The different stress extraction method also implies the use of different S‐N curves. A large number of fatigue tests carried out in the past have been re‐evaluated to determine the hot‐spot stress S‐N curves. Additional fatigue tests have been carried out for details lacking data. The study has resulted in a guideline to design OBD for fatigue with the hot‐spot stress method. This guideline, TS 1993‐1‐901:2023, will be published as a Technical Specification (TS) to the standard prEN 1993‐1‐9:2023.This paper provides a short background to the newly created TS. It demonstrates the derivation of S‐N curves based on available tests for a number of details. It highlights fatigue relevant details that are missing in prEN 1993‐1‐9:2023 and that are added to TS 1993‐1‐901. It explains how to evaluate cracks starting from the root of the weld, for which the hot‐spot stress method is traditionally not applicable. Finally, the paper demonstrates how the method can be applied in the fatigue design, including the application of the load in finite element models.

Experimental Investigation on Fatigue Improvement of Orthotropic Steel Bridge Deck Using Steel Fiber Reinforced Concrete

AbstractThe high-performance topping concrete overlay would significantly reduce the fatigue stresses at susceptible details of orthotropic steel deck (OSD) and effectively improve the fatigue performance. Full-scale fatigue tests and numerical simulations were carried out to quantify the effects of steel fiber reinforced concrete (SFRC) topping pavement in reducing the OSD fatigue stresses based on a practical bridge design. Fatigue stress of the OSD critical details was measured from tests and cracking was observed in the SFRC overlay. Both an innovative pre-pump-pulse Brillouin optical time domain analysis (PPP-BOTDA) distributed optical fiber sensor and strain gauges were also used to measure the stress at OSD fatigue-prone details, including the crossbeam cut-out, rib-to-deck weld, rib-to-crossbeam weld and splice of U-rib. The corresponding three-dimensional (3-D) finite element model was then established and verified by the test results, and used to conduct a parametric study to obtain a quantitative expression of fatigue stress reduction factor, in terms of relative elastic modulus and thickness of overlay and steel deck plate. The proposed quantitative model of the fatigue stress reduction effect can guide the cost-effective design of composite bridge deck.

A New design of deployable pedestrian bridge deck based on origami theory

As one of the basic civil engineering structures, bridges greatly impact people’s daily life. However, many bridge accidents are caused by boat crashes because of the driver’s carelessness or other climatic and hydrological factors. Besides, some pedestrian bridges are not frequently used and thus make a waste of water space. This design will overcome the challenge and tackle the problem successfully based on the origami and kirigami theory by using a connector composed of a slider and a revolute joint. The bridge can be folded up and down via a particular folding method. The basic structure units have two degrees of freedom (DOF). The whole mechanism can be folded and unfolded by sliding and rotating the connector. According to the structural folding position analysis results shown in the diagrams, the new deployable bridge deck structure design can validly tackle the problems of clearance limitation under the bridge via the special-designed cross-section of the bridge deck. I hope the design model will be widely applied in the river-crossing bridge and bring convenience to all pedestrians and boat drivers.