Structure and Infrastructure Engineering
ISSN / EISSN : 1573-2479 / 1744-8980
Published by: Informa UK Limited (10.1080)
Total articles ≅ 1,637
Latest articles in this journal
Structure and Infrastructure Engineering pp 1-20; https://doi.org/10.1080/15732479.2022.2077379
Impact-induced damage to piles threatens bridge safety. Hence, the impact behaviour of a widely employed type of steel casing composite (SCC) pile needs to be investigated. To improve the understanding of the impact behaviours of SCC piles, pendulum impact tests were conducted on 21 specimens. The effects of the steel casing length, impact mass and velocity, and superstructure mass on the impact responses and failure mode of the piles were systematically investigated. In the absence of the upper mass (during the construction stage of bridges), piles with the optimum steel casing length sustained flexural failure within the wrapped region, whereas the short steel casing led to a more concentrated and brittle failure of the uncased concrete near the casing bottom. Furthermore, with an increase in the impact velocity, failures of piles with short steel casings transferred from bending to bending-shear. However, in the presence of the upper mass (during the service stage), piles with the optimum casing length failed in the cap-pile joint owing to high inertia. By revealing the failure behaviour of SCC piles under different impact conditions, the present study provides insight into the impact design and damage evaluation of SCC piles in practice.
Structure and Infrastructure Engineering pp 1-23; https://doi.org/10.1080/15732479.2022.2074469
As an important part of a bridge, bearings are vulnerable to damage when exposed to various loading and environmental changes during their lifetime, resulting in the necessitating repair or replacement operations. The investigation and maintenance of bearings’ diseases are helpful to prolong their durability. Compared with laboratory research, the field investigation of bearing diseases is more representative due to the realistic working environment. In this paper, the defects of 10,486 bearings in 19 expressway bridges and 8,862 bearings in 5 high-speed railway (HSR) bridges in Eastern China are inspected through manual on-site visual observation and parameter measurement, followed by a large amount of bearing diseases data obtained to perform a statistical analysis for evaluating many aspects, including the classification and the potential causes of the bearing diseases, the service status. Finally, a three-level maintenance strategy for bearings is developed and applied to the replacement of 1,166 bearings in eight expressway bridges and 15 bearings in seven girders of HSR bridges. The results show that most diseases of elastomeric bearings are caused by design defects but for pot or spherical by the problems remaining from bearings installation, and the proposed bridge jacking scheme and bearing replacement technologies are efficient, labour- and material-saving.
Structure and Infrastructure Engineering pp 1-12; https://doi.org/10.1080/15732479.2022.2074468
In this paper, a finite element model of a highway bridge pier subjected to debris flow is established, which comprises a double-column pier, a gully channel, moving fluid and solid particles. By using the arbitrary Lagrangian-Eulerian (ALE) algorithm to calculate the fluid-solid coupling effect, the process of debris flow impacting on the pier is simulated. Based on the ‘two-phase flow’ theory, a simplified equation to calculate the impact force of debris flow containing both fluid and solid phases is proposed, and the variable parameters in the equation are determined through numerical simulation using the established FE model and the field-measured data. By comparing with the historical records of actual debris flows, the effectiveness of the numerical model and the proposed equation is verified. A reliability model of the pier subjected to debris flow is established, and the structural vulnerability is estimated by the MCS method. Using the site-observed data, the failure mode of a highway double-column pier subjected to impact of two-phase debris flow is studied. The critical velocities of debris flow causing the structure to have different modes of damage, and the critical impact height of debris flow on the pier suffering bending and shear failures are determined.
Structure and Infrastructure Engineering pp 1-12; https://doi.org/10.1080/15732479.2022.2069272
Image based-corrosion detection has become a widespread practice for steel structures, but fine-tuning their model parameters is time-consuming. Alternatively, convolutional neural networks (CNNs) can also be trained fast and automatically, but they demand a huge training dataset. In this paper, a corrosion detection approach based on an artificial neural network (ANN) whose training dataset size is less than 0.1% of that of typical CNNs is introduced. The input layer of the proposed ANN consists of textural and color properties. In the present work, different color spaces and textural properties are examined for their impact on the robustness of the ANN. Results reveal that the best color channels can be achieved by combining CIE L*u*v* and YUV color spaces. Moreover, energy is selected as the best texture feature with respect to the ANN robustness. The proposed ANN outperforms an available image processing algorithm from the perspective of both speed and accuracy. In conclusion, this ANN can be used for actual applications after a fast and straightforward training step.
Structure and Infrastructure Engineering pp 1-16; https://doi.org/10.1080/15732479.2022.2063907
Seismic isolation is an effective technology for mitigating the seismic damage to bridges. However, rupture and large cracks of laminated rubber bearings, including lead rubber bearings, have occurred at several bridges during recent earthquakes. Preventing the rupture of seismic isolators by considering uncertainties and variations in the mechanical properties due to ageing deterioration can improve the ductility capacity of the bridge systems when subjected to extreme ground motions. This study presents a time-dependent seismic reliability assessment methodology for isolated bridges that considers long-term ageing deterioration of lead rubber bearings. The effects of capacity hierarchy between the isolator and the column, as well as the ageing deterioration of isolators on the seismic reliability and the predominant ultimate failure mode were clarified. It was found that the effect of ageing deterioration of lead rubber bearings on seismic reliability is relatively smaller than that of the difference in seismic hazards at different sites. Furthermore, the seismic safety of isolated bridges can be significantly improved by setting an adequate capacity hierarchy between the isolator and the column, as it can prevent the rupture of the isolator under extreme ground motions considering the ageing deterioration of the isolator.
Structure and Infrastructure Engineering pp 1-13; https://doi.org/10.1080/15732479.2022.2065687
The durability of reinforced concrete (RC) structures and infrastructure has been the subject of significant attention from the engineering research community in recent years, mainly owing to the deterioration of RC elements due to corrosion of the embedded steel reinforcement. In this context, stainless steel reinforcement can provide an efficient solution to enhance the expected lifetime of concrete structures, reducing the damage due to corrosion of the reinforcement and carbonation and deterioration of the concrete. However, current international design standards for reinforced concrete structures do not include appropriate guidance for stainless steel reinforced concrete (SSRC). In order to investigate the behaviour of stainless steel RC beams, a series of six beam tests was conducted and is discussed herein. The key performance measures for RC beams such as load-deflection response, cracking behaviour and deflections at service load are assessed. The validity and applicability of existing design rules, which were developed for carbon steel RC, are also examined for stainless steel reinforced concrete members. Other recently developed design procedures, based on the Continuous Strength Method and including an accurate material model for the stainless steel bars, are also examined.
Structure and Infrastructure Engineering pp 1-20; https://doi.org/10.1080/15732479.2022.2063908
Bridges constitute an important part of the infrastructure and are subjected to damage and deterioration of materials and support conditions, as well as exposure to adverse environmental conditions. Continuous or repeated monitoring of structural responses may add important information for decision-making regarding their maintenance, repair and reinforcement. The use of these data, in conjunction with techniques of structural reliability for the treatment of the uncertainties, allows a better understanding of the structural behaviour and integrity. Modern Information and Communication Technologies can greatly contribute to the improvement of the maintenance capacity and, consequently, to the reliability of the assets and to their operational availability. New wireless communication technologies, such as 5 G networks, are considered as the enabling technologies of the digital transformation, integrated with the concept of the Internet of Things. High connectivity capacity and intensive automation enable, for example, changes in inspection paradigms and asset maintenance, by transferring the product focus to service platforms, bringing gains to productivity, comfort, operational safety and costs. New predictive maintenance approaches, which make use of a large amount of data available, can improve the efficiency of maintenance processes, producing more accurate and reliable anticipated diagnostics. The Digital Twins incorporate all these tools and allow a real-time view of the evolution of the asset behaviour. This concept applied to a railway bridge is presented and discussed in detail in this paper.
Structure and Infrastructure Engineering pp 1-16; https://doi.org/10.1080/15732479.2022.2063905
In this study, the expansion and deformation of alkali–silica reaction (ASR)-affected concrete structures under natural environment and multiaxial stress state are predicted. The performance of the ASR model proposed in previous research is quantitatively investigated in terms of relative humidity, multiaxial stress, and temperature dependencies based on experimental results. The simulation results indicate that the relative humidity-dependent expansion caused by the ASR can be simulated effectively by slightly modifying the relative humidity threshold in the model. In a simulation focusing on stress dependency, the insufficient consideration of the relationship between compressive stress and ASR gel absorption into pores in the model by previous research resulted in discrepancies between the simulation and experimental results. The performance of the model by previous research in simulating temperature dependency is improved by referring to the relationship between the expansion rate and temperature recorded from specimens exposed to the real environment. An exposure experiment of reinforced concrete (RC) slab on steel girders is simulated using the modified model. The results show that the modified model can reproduce the tendency of three-dimensional deformation of RC slab, while model improvement considering time-dependent and stress-dependent phenomena should be needed for long-term quantitative predictions.
Structure and Infrastructure Engineering pp 1-23; https://doi.org/10.1080/15732479.2022.2063906
Nowadays, with the aging of the bridges and the advancements in technology, load testing has emerged as an effective method to assess existing concrete bridges with missing information, or where analytical methods do not provide an accurate assessment. Two types of load tests are identified: diagnostic load tests and proof load tests. Both rely on field measurements of parameters or structural responses of the bridge during the test. A diagnostic load test measures the response of the bridge so that analytical models can be calibrated and evaluated. In a proof load test, the bridge directly demonstrates that it can carry a certain load. Since large loads are applied, the bridge needs to be carefully monitored. In this case, monitoring the measurements provide a warning to avoid damage. This paper reviews the literature on reported load tests and the measurement techniques used during these tests. It also includes a review of traditional and recently developed sensing technologies. Finally, the measurement requirements for diagnostic and proof load tests are given as well as a flow chart to guide engineers in the selection process of appropriate monitoring and measurement techniques during load tests. This paper can serve engineers during the preparation of a load test.
Structure and Infrastructure Engineering pp 1-15; https://doi.org/10.1080/15732479.2022.2061017
The increase of road freight around the world, alongside limited funding on bridge infrastructure, demands objective and accurate safety assessments for greater loads to achieve better utilization of existing aging bridges. Probability-based bridge assessment (PBBA) is already recommended around the world as a higher-tier assessment beyond current deterministic methods. However, its uptake in international practice lags behind that merited. The promotion of PBBA in practice hinges on four aspects: (i) justification, through proof of concept; (ii) accessibility, through integration into current practice; (iii) effectiveness, through utilizing state-of-the-art tools, and; (iv) familiarity, through clear communication and education. This paper describes a recent Austroads research project that has developed solutions to these aspects to promote the adoption of PBBA in Australia. The experience gained in developing the freely available guideline is described in this paper to support the promotion of PBBA adoption in other countries.