Stainless Steel Corrugated Web Girders for Composite Road Bridges: Concept Evaluation and Flange Buckling Resistance

Achieving a sustainable bridge design requires careful consideration of economic viability and environmental impact over the entire lifespan of the structure. While stainless steel is recognized for its excellent life cycle performance, its high cost prevents it from being used to a larger extent in bridges. In this thesis work, a new solution is investigated to mitigate this issue. The new solution comprises the use of corrugated webs in stainless steel girders which is expected to result in reduced material consumption and cost. The work in this thesis focuses on two problem areas in this field. First, a study is performed to examine the competitiveness of the new concept in relation to conventional designs of steel-concrete composite road bridges. The second part of the work focuses on the problem of flange buckling in girders with corrugated webs. Previous research has shown that the design models developed\ua0for flange buckling resistance, including the one in EN 1993-1-5, frequently result in unsafe design. Furthermore, these models were developed for carbon steel and have not been updated for stainless steel. To explore the economic and environmental benefits of the new concept, two studies have been conducted. Firstly, three design solutions are examined on a case study bridge with three continuous spans. These design solutions include carbon steel flat web, stainless steel flat web, and stainless steel corrugated web girder bridges. A genetic algorithm is used to optimize each design solution in terms of weight. The three optimal solutions are then assessed in terms of investment costs, life cycle costs (LCC), and environmental life cycle impact. Secondly, two of the considered design solutions, namely carbon steel flat web and stainless-steel corrugated web girders, are employed to conduct multiple parametric studies using a simply supported reference bridge. For both design solutions, the effects of optimization targets on weight, investment cost, life cycle cost, and environmental life cycle impact are initially investigated. Following that, the focus is put on the life cycle cost (LCC) as an optimization target, and the impact of various design input parameters is investigated. These parameters include span length, girder depth, average daily traffic (ADT) with the associated number of heavy vehicles per slow lane (Nobs), and time intervals and expenses for maintenance activities. Furthermore, a sensitivity analysis is conducted to study the influence of the inflation rate and discount rate. The results indicate that the new concept offers considerable potential saving in weight, life cycle costs, and life cycle impacts for both simply supported and continuous bridges. The saving is more apparent with deeper girders, higher ADT, and more intense maintenance activities. Saving is also larger when inflation is high and discount rate is low.After studying the potential of corrugated web girders to reduce costs and environmental impacts in the case of employing stainless steel, a study of the flange buckling behaviour in duplex stainless-steel girders is conducted in this work. A parametric finite element model is developed and validated with tests conducted on beams made of carbon steel. The material is then changed to EN1.4162, and linear buckling analysis (LBA) and geometrically and materially nonlinear analysis with imperfections (GMNIA) are carried out on 410 girders with typical bridge girder dimensions. The results are compared to previously developed models for carbon steel, and a new buckling curve and flange local buckling design procedure for duplex stainless-steel girders with corrugated webs are proposed. The study shows that the new proposed design model generates more accurate estimates of flange buckling resistance than previous proposed models

Vehicle Axle Load Identification Using Extracted Bridge Influence Line via Updated Static Component Technique

Bridge weigh-in-motion or moving force identification systems have been developed to screen the heavy truck or monitor its gross weight and axle loads. Bridge surface roughness has been considered a very sensitive parameter to the identification error. This paper presents the algorithm to accurately identify static axle weights by modifying the identification process to include the measured bridge influence line containing the actual road profile. The existing iterative calculation called the updated static component (USC) technique is also utilized to improve the dynamic axle load accuracy. The extracted influence line is obtained from a low-speed test using a known axle weight truck. Therefore, the characteristics of the road roughness and the measurement noise are included in the bridge responses. The effectiveness of the proposed technique is investigated through the numerical simulation and the experiment using scaled models. The results reveal that the identified axle loads become more accurate than those identified using the USC and the conventional regularized least squares methods. The proposed technique effectively decreases the identification errors of moving axle loads on the rough surface with a high measurement noise level. Moreover, the regularization parameter can be easily assigned with a broader range to achieve accurate identification results

Structural health monitoring of bridges using wireless sensor networks

Structural Health Monitoring, damage detection and localization of bridges using Wireless Sensor Networks (WSN) are studied in this thesis. The continuous monitoring of bridges to detect damage is a very useful tools for preventing unnecessary costly and emergent maintenance. The optimal design aims to maximize the lifetime of the system, the accuracy of the sensed data, and the system reliability, and to minimize the system cost and complexity Finite Element Analysis (FEA) is carried out using LUSAS Bridge Plus software to determine sensor locations and measurement types and effectively minimize the number of sensors, data for transmission, and volume of data for processing. In order to verify the computer simulation outputs and evaluate the proposed optimal design and algorithms, a WSN system mounted on a simple reinforced concrete frame model is employed in the lab. A series of tests are carried out on the reinforced concrete frame mounted on the shaking table in order to simulate the existing extreme loading condition. Experimental methods which are based on modal analysis under ambient vibrational excitation are often employed to detect structural damages of mechanical systems, many of such frequency domain methods as first step use a Fast Fourier Transform estimate of the Power Spectral Density (PSD) associated with the response of the system. In this study it is also shown that higher order statistical estimators such as Spectral Kurtosis (SK) and Sample to Model Ratio (SMR) may be successfully employed to more reliably discriminate the response of the system against the ambient noise and better identify and separate contributions from closely spaced individual modes. Subsequently, the identified modal parameters are used for damage detection and Structural Health Monitoring. To evaluate the preliminary results of the project\u27s prototype and quantify the current bridge response as well as demonstrate the ability of the SHM system to successfully perform on a bridge, the deployment of Wireless Sensor Networks in an existing highway bridge in Qatar is implemented. The proposed technique will eventually be applied to the new stadium that State of Qatar will build in preparation for the 2022 World Cup. This monitoring system will help permanently record the vibration levels reached in all substructures during each event to evaluate the actual health state of the stadiums. This offers the opportunity to detect potentially dangerous situations before they become critical

Modelling, Test and Practice of Steel Structures

This reprint provides an international forum for the presentation and discussion of the latest developments in structural-steel research and its applications. The topics of this reprint include the modelling, testing and practice of steel structures and steel-based composite structures. A total of 17 high-quality, original papers dealing with all aspects of steel-structures research, including modelling, testing, and construction research on material properties, components, assemblages, connection, and structural behaviors, are included for publication

Behavior of Metallic and Composite Structures (Second Volume)

Various types of metallic and composite structures are used in modern engineering practice. For aerospace, car industry, and civil engineering applications, the most important are thin-walled structures made of di erent types of metallic alloys, brous composites, laminates, and multifunctional materials with a more complicated geometry of reinforcement including nanoparticles or nano bres. The current applications in modern engineering require analysis of structures of various properties, shapes, and sizes (e.g., aircraft wings) including structural hybrid joints, subjected to di erent types of loadings, including quasi-static, dynamic, cyclic, thermal, impact, penetration, etc.The advanced metallic and composite structures should satisfy multiple structural functions during operating conditions. Structural functions include mechanical properties such as strength, sti ness, damage resistance, fracture toughness, and damping. Non-structural functions include electrical and thermal conductivities, sensing, actuation, energy harvesting, self-healing capability, electromagnetic shielding, etc.The aim of this SI is to understand the basic principles of damage growth and fracture processes in advanced metallic and composite structures that also include structural joints. Presently, it is widely recognized that important macroscopic properties, such as macroscopic sti ness and strength, are governed by processes that occur at one to several scales below the level of observation. A thorough understanding of how these processes influence the reduction of sti ffness and strength forms the key to the design of improved innovative structural elements and the analysis of existing ones

Heuristic Optimization of a New Type of Prestressed Arched Truss

[EN] This paper represents new approaches for calculating, designing, and optimizing prestressed arched trusses with a tie member. Structural systems with long spans, such as trusses, beams, frames, etc., are subjected to a considerable/substantial risk of losing load-carrying capacity because of the different types of loads used. Some traditional design methods define the values of prestressing force in the tie member and internal forces in the truss elements to avoid this load capacity loss. However, the accuracy and limits of the determination of the forces are not necessarily known. The authors offer a new type of prestressed arched truss and some new approaches in the design and calculation process to solve these disadvantages. The study¿s main objectives were to design an innovative and new geometric form of prestressed arched truss, which allows the development of high-value prestressing force, to optimize a new truss for reducing self-weight, increasing load-carrying capacity compared to its analogs. The force, stiffness matrix, and simulated annealing methods were used during the study. A new advance to the optimization of prestressed arched truss suggested by the authors reduces the self-weight and improves the load capacity of the truss by 8¿17%, depending on the span.This research was funded by the Erasmus Mundus Action 2 Project Electra: Enhancing Learning in ENPI Countries through Clean Technologies and Research related Activities (project: ELEC1400294), Erasmus+ program InnoCENS-Enhancing innovation competences and entrepreneurial skills in engineering education (project: 573965-EPP-1-2016-1-SE-EPPKA2-CBHE-JP). Grant PID2020-117056RB-I00 funded by MCIN/AEI/ 10.13039/501100011033 and by ERDF A way of making Europe.Partskhaladze, G.; Alcalá-González, J.; Medzmariashvili, E.; Chavleshvili, G.; Surguladze, B.; Yepes, V. (2022). Heuristic Optimization of a New Type of Prestressed Arched Truss. Materials. 15(22):1-20. https://doi.org/10.3390/ma15228144120152

Influence of Span to depth ratio in designing concrete bridges

The influence of the span-to-depth ratio in designing concrete bridges is a critical aspect of bridge engineering. This study focuses on investigating the span-to-depth ratios of reinforced concrete bridges and post-tensioned concrete bridges. The main objective of the research is to establish a new basis for determining the height of the bridge deck based on selected span lengths for three-span simply supported reinforced and post-tensioned plate bridges. Nine bridge models with varying mid-span lengths ranging from 8 to 40m are analyzed to examine the relationship between the mid-span length and plate thickness. These models cover a range of mid-span to plate thickness ratios from 17.77 to 34.28. The side spans is set to 0.3 times the total bridge length (L), and the mid-span is set to 0.4 times the total bridge length (L). The transition point from reinforced to post-tensioned concrete is identified, and the optimal span-to-depth ratio for reinforced concrete bridges is determined. The bridge models are analyzed using the Sofistik software and its Teddy programming language (CADINP), considering design requirements for ultimate limit state (ULS) and serviceability limit state (SLS). The research adopts a parameterized approach, utilizing code in Sofistik to automatically generate bridge models based on input parameters, such as bridge length and depth. This parameterization allows for efficient and automated generation of loads and actions, dynamically adjusted whenever new structural parameters are inputted. As a result, comprehensive analysis of various load and action scenarios can be performed, specifically tailored to the specific bridge length. This approach enables a thorough exploration of the bridge's behavior under different loading conditions, leading to a more informed and optimized design. The analysis reveals that the ULS governs the design for bridge models 8, 12, and 16, while the SLS governs the design for bridge model 20. For post-tensioned bridge models, the SLS governs the design for all of them. The findings demonstrate that the required cross-section height of a bridge varies with the span length. Specifically, the transition from reinforced to post-tensioned concrete occurs at a bridge length of 60m or when the middle span length is 24m. Additionally, the deflection control meets the requirements specified by EC2 and N400, ensuring the structural functionality of the bridges