Damage to buried pipes under seismic landslide actions has been reported in many post-earthquake reconnaissance. The landslide-pipe problem in the technical literature has been often investigated using simplified analytical methods. However, the analytical methods ignore the real mechanism of pipe response under natural dynamic slope instability. The dynamic slope instability is significantly influenced by its lateral boundary interface (LBI) characteristics. In this study, slope-pipe interaction (SPI) under seismic loading, focusing on the effect of LBI properties, is evaluated by continuum numerical simulation using the SANISAND constitutive model in FLAC3D. The results show that the geometry of the failure mass varies from 2D to 3D by increasing the stiffness at the slope boundaries (from smooth to hard) and the maximum pipe deformation decreases by around 40%. Moreover, the response components of maximum axial stress, bending moment, and shear stress of the pipe occur at the end sections of the buried pipe and near the boundaries of the landslide zone. However, the maximum pipe deflection occurs in the middle section of the pipe. The results of shear force-shear displacement curves demonstrate that the soil-pipe interaction stiffness is variable along the pipe length and can be estimated by a hyperbolic equation.

Shear failures in reinforced concrete structures occur with little or no warning. Reinforced concrete members with shear cracks should be evaluated to ensure safety. Existing evaluation methods have large variability, require time-consuming modeling or expert opinion. This study uses machine learning to investigate correlations of crack width with shear loading, stiffness, and stirrup strain histories. Experimental literature enables the assembly of a database of rectangular reinforced concrete slender beams with crack width measurements for beams with shear reinforcement amounts smaller and larger than the minimum required by ACI 318-19. Measured data include crack widths from 122 beams, load–displacement relationship from 100 beams, and stirrup strains from 46 beams. Gaussian Process Regression is used to correlate crack width and geometric, material and design properties to shear loading, stiffness, and stirrup strain histories. Ten-fold cross validation training shows mean absolute percent errors of 18, 33 and 77% for shear, stiffness, and stirrup strain history predictions. The proposed algorithms can be used to accelerate the evaluation of in-service structures and can be updated upon availability of additional data.

Bridges, as an important part in modern infrastructure networks, suffer from increasingly severe aging issues in recent years. Road agencies and authorities conduct regular inspections for their bridges and identify defects and deteriorations for condition assessment. Such defect information cannot be efficiently used for analysis in the structural domain. This study proposes an Industry Foundation Classes-based method to allow for the transfer from a defective bridge information model to a defect analysis model. The architectural model of bridge is first converted into analytical model and then the impacts of defects on structural properties are quantified with a stiffness reduction coefficient. Case studies are conducted to validate the applicability of the proposed method for defect analysis and a range of coefficients are tested on an illustrative case bridge. The results prove that the proposed method can generate instructive and informative knowledge on the safety and reliability of the entire structure. This study narrows the gap between the empirical condition assessment scheme and the numerical structural analysis scheme for bridge management and manages to make full use of inspection-related information within Building Information Modelling (BIM) environment.

Internal replacement pipe (IRP) is an innovative trenchless technology for the rehabilitation of legacy steel and cast-iron pipelines. This advanced IRP system must be properly designed so that it can safely and effectively restore the service of damaged pipelines. This paper studies the axial behaviour of IRP systems for repairing pipelines with circumferential host-pipe discontinuities under seasonal and extreme levels of temperature change. Analytical solutions along with a total of 270 linear and nonlinear finite element (FE) simulations, validated against experimental results and available closed-form solutions, were used for a parametric study on the effects of geometrical and material properties on axial stresses and deformations of IRP systems subjected to temperature change. Effects of the internal pressure, material and geometric nonlinearities, and different modes of IRP-host pipe unbonding were also investigated. An analytical model was developed for the prediction of temperature change induced loading and response of the IRP system. Using the results obtained from a comprehensive FE-based parametric study, three modification factors were extracted for the application to the developed analytical model in order to accurately predict the maximum axial stress of IRP and the opening of a circumferential host-pipe discontinuity subjected to various levels of temperature change.

This paper presents a framework for estimating the cause of damage to bridge members by combining Structure from Motion (SfM) and Visual Question Answering (VQA) techniques. A VQA model was developed that uses bridge images for dataset creation and outputs the damage or member name and its existence based on the images and questions. In the developed model, the correct answer rate for questions requiring the member or damage name were 67.4 and 68.9%, respectively. The correct answer rate for questions requiring a yes/no answer was 99.1%. Based on the developed model, a damage cause estimation method was proposed. In the proposed method, the damage causes are narrowed down by inputting new questions to the VQA model, which are determined based on the surrounding images obtained via SfM and the results of the VQA model. Subsequently, the proposed method was then applied to an actual bridge and shown to be capable of determining damage and estimating its cause. The proposed method could be used to prevent damage causes from being overlooked, and practitioners could determine inspection focus areas, which could contribute to the improvement of maintenance techniques. In the future, it is expected to contribute to infrastructure diagnosis automation.

Surface transportation systems play a vital role in supporting a region’s functionalities. They are expected to remain operational before and even after a hazardous event (e.g. an earthquake). The importance is evident to estimate the post-disaster performance of traffic systems under a probability-based framework, considering the uncertainties arising from both the hazards and the transportation infrastructure fragilities. This paper proposes an explicit approach for evaluating the performance of transportation systems immediately after an earthquake event. The method estimates the spatial distribution of vehicles in the traffic network in a closed form and thus is relatively efficient compared with traditional methods (e.g. an agent-based method). The applicability of the proposed approach is demonstrated through an application to the post-earthquake performance assessment of the traffic network in Tangshan City, China, a city that suffered catastrophically from the 1976 Tangshan Earthquake. Analytical results show that the proposed method can well reflect both the temporal and the spatial variations of the traffic flow, and thus offers rational support for predicting the post-earthquake traffic scenarios and for optimizing strategies to improve the transportation capability under emergent conditions.

Keyed dry joints are commonly utilised in segmental bridges for shear stress transmission. The aim of this study is to explore the shear behaviour and capacity of large shear key dry joints. The considered parameters included key base height, key number and concrete strength. The key base heights were found to have a significant impact on the failure mode and shear carrying capacity. When the key base height is increased by 100%, the shear carrying capacity of the joint is increased by 156%. Digital image correlation (DIC) and distributed fibre optic sensing (DFOS) technologies revealed the characteristics of load transfer in the large shear key, validated the principle of inclined strut column and observed the changing angle of inclined column with the increase in shear key size. Moreover, due to the shear transfer at the large key teeth, there is a trend of separation in the lower contact surfaces of the joint. Based on these findings, an improved calculation method for the shear strength of large key dry joints was established. The calculation results show more accurate predictions for large key dry joints than available calculation methods developed for smaller keyed dry joints.

Temperature variation causes geometrical irregularity and additional internal loads in railway systems. The geometrical irregularity and additional internal loads can adversely influence the dynamic behaviors of trains, therefore compromising the safety and ride comfort of trains. This paper presents an analytical study on the deformations and internal loads of railways with CRTS I ballastless tracks on an arch bridge. The bridge is located in the Sichuan-Tibet Railway Line within a high-altitude mountainous terrain exposed to significant temperature variations. This research derives analytical formulae to analyze the deformations and internal loads of railways under various temperatures and thermal gradients. The formulae are utilized to evaluate the effects of the stiffness of fasteners and the stiffness of isolation layers of CRTS I ballastless tracks. The results show that temperature changes cause significant vertical deformations and rotations of rails, and reducing the stiffness of fasteners and isolation layers is effective in mitigating rail deformations under the thermal effects.

As critical lifeline systems, transportation network (TN) and electric power network (EPN) are highly susceptible to natural hazards, such as earthquakes during their service life. At the same time, restoration of damaged TN and EPN is essential to support the post-earthquake reconstruction and emergency rescue in affected areas. Restoration strategies were traditionally developed for TN or EPN separately. However, neglecting the potential interconnection between these two networks in the recovery phase may lead to detrimental consequences, as in real-world scenarios, the obtained strategy may be less efficient or even unfeasible given that recovery of one system is usually dependent on the others for service provision. Accordingly, this paper presents a resilience-based framework for post-earthquake restoration of interdependent transportation-electric power networks. In this framework, restoration independencies and functionality dependencies are introduced to represent the interaction between TN and EPN. Then, a bi-level optimization model with the objective of maximizing seismic resilience is established to characterize the network recovery problem. Furthermore, a solution algorithm that incorporates a genetic algorithm and a chromosome validity test operator is designed to obtain the near-optimal solution. Finally, the proposed framework is illustrated through two numerical examples.

The combination of large-diameter steel strands and ultra-high-performance concrete (UHPC) presents a promising opportunity to improve the performance of prestressed concrete structures. However, investigations on the bond between them, which determines important design parameters such as the anchorage length of the strand, are insufficient. This study performs pull-out tests of 18-mm-diameter steel strands embedded in UHPC to investigate the bond property. The test data is analyzed to determine the effects of embedment length, concrete cover depth, and stirrup ratio on the bond property. Based on the analysis, a bilinear bond-slip model is calibrated following the principle of energy equivalence. Moreover, an empirical formula for the maximum bond stress is proposed. According to the obtained bond properties, the anchorage length of the strand is evaluated using the approximate probability method, and the results are comparable with the values given in several design codes.