Hasil untuk "Bridge engineering"

Junjie Gong, Xin Liu, Yuan Gao et al.

Foam lightweight soil (FLS) has emerged as a promising material in geotechnical engineering due to its low density, high load-bearing capacity, and ability to incorporate industrial by-products such as fly ash. It offers significant advantages in mitigating settlement and improving stability for embankments constructed on soft soil foundations. However, the combined influence of key parameters—including layered filling thickness, bulk density, and geogrid reinforcement—on the long-term performance of FLS embankments remains insufficiently understood. This study investigates the settlement behavior and stability of FLS embankments through a combination of field experiments and finite element simulations over a 15-year period. The results indicate that layered filling thicknesses of 500–600 mm achieve the best balance between settlement control and construction feasibility. When the thickness exceeds 800 mm, not only does the uniformity deteriorate, but the settlement also increases. Experimental results showed that a medium bulk density of 6 to 8 kN/m³ is optimal as a balance between strength and settlement behavior. Furthermore, geogrid reinforcement significantly improved stability, with safety factors increasing by up to 1.87 compared to unreinforced sections. The findings provide practical guidelines for the design and construction of FLS embankments, particularly for bridge approaches and soft soil foundations. In addition to improving structural performance, the incorporation of industrial by-products highlights the potential of FLS as a sustainable and cost-effective material for future infrastructure development.

M. V. Gvintovkin

The article examines the problem of the gap between the detailed results of machine learning in the tasks of quality diagnostics in mechanical engineering and the needs of quality management systems in complex, interpretable and standardized reporting. An intelligent system based on synergistic integration of distributed machine learning modules for local diagnostics and large language models for automatic generation of context-dependent reports of the quality management system is proposed. The methodology, system architecture, algorithms of aggregation of diagnostic information, techniques of engineering of proxies for large language model and mechanisms of verification of generated reports are described, including factchecking for minimization of «hallucinations».The results of the pilot testing on typical quality control tasks confirm system performance, high accuracy of machine learning modules components and ability to generate factually accurate, relevant and compliant quality management system reports. The proposed approach allows to effectively bridge the gap between technical diagnosis and management needs of quality management system, automating the process of forming intellectual reporting on quality.

Henry Prastanto, Illah Sailah, Ono Suparno et al.

The characteristics of natural rubber greatly influence the quality of asphalt modified with natural rubber. This research uses natural rubber of the Technical Specified Rubber (TSR) 20 type, which in Indonesia is called Standard Indonesian Rubber (SIR) 20 as the raw material. The sulfur vulcanization material is expected to increase crosslinks so that it can increase the resistance of natural rubber to hot asphalt and can improve the quality of rubberized asphalt. This research was designed by varying the sulfur dosage and vulcanization duration. The sulfur dosage used varies, namely 5; 10; 15; 20 parts per hundreed rubber (phr). The duration of vulcanization time at 140 °C for each dose of sulfur is 0;30;60;90;120 min. The compound or vulcanisate is then mixed into the asphalt at a temperature of 160–170 °C with a dose of 2 % rubber and 98 % asphalt. Based on the research results, it is known that increasing the sulfur dosage and vulcanization time duration produces rubber that is more resistant to oil through testing for solubility and swelling in toluene. The unvulcanized compound dissolves in toluene, while the vulcanizate swelling ratio decreases with increasing sulfur dosage (790 to 482 %). Increasing the sulfur dosage and the duration of vulcanization time produces harder rubber so that the duration of mixing into asphalt increases from 1.5 h to 5.5 h. The addition of sulfur dosage and vulcanization time duration can increase the original Performance Grade (PG) and PG after Rolling Thin Film Oven Test (RTFOT) when compared to original asphalt. Original PG of rubberized asphalt obtained from this research is 69.8 to 90.4 °C compared to original asphalt PG which is only 66.7 °C. PG after RTFOT was obtained between 60.3 to 88.4 °C compared to original asphalt PG which was only 64 °C. This research data can be useful in the design of rubber compounds and vulcanizates which can be selected by considering process engineering, processing machines and economic aspects in the production of rubberized asphalt.

GUO Yongjia, JIN Yong, LUO Chufan et al.

High-content SBS-modified asphalt has been widely used in high-grade highway pavement engineering due to its excellent mechanical properties and adaptability to heavy traffic. However, its application is hindered by high energy consumption and poor workability at elevated temperatures, which limits the development of green and efficient construction practices. In this study, on the basis of warm mix technology, a self-developed organic viscosity-reducing warm-mixed additive was incorporated to establish a warm-mixed asphalt mixture system with high-content SBS modification. With SMA-13 as the target gradation, the mixing and compaction workability was evaluated. A self-developed apparatus for mixing workability testing was used to determine the minimum mixing energy consumption as an evaluation indicator of mixing workability. Meanwhile, a gyratory compactor was used to obtain the compaction slope for quantifying compaction workability. The test results show that the representative torque value of the warm-mixed mixture at 155 ℃ is close to that of the conventional mixture at 175 ℃, with a 15.3% reduction in minimum mixing energy consumption. In the compaction test, the warm mix system at 140 ℃ achieves a slightly higher compaction slope compared to the conventional system at 160 ℃. Overall, the results demonstrate that warm mix technology enables a 20 ℃ reduction in construction temperature while significantly improving both mixing and compaction workability.

Tianyou Tao, Peng Deng, Fan Xu et al.

The tropical storm is a severe wind disaster that frequently attacks coastal structures and infrastructure facilities. Accurate wind speed forecasting of tropical storms, based on real-time measured data, has become a critical issue in the engineering community. Utilizing the measured data of typical tropical storms at Sutong Bridge, this study develops a new approach for wind speed forecasting, which integrates multi-step differencing with an artificial neural network-based model. Given the non-stationary nature of tropical storm wind speeds, a multi-step differencing operation is initially applied to the wind speed time series. Subsequently, multi-step predictions of the differenced wind speeds are made for future time points. Finally, an inverse differencing operation is employed to reconstruct the wind speeds to be forecasted. The forecasting errors associated with single-step differencing, multi-step differencing, and no differencing are compared to evaluate their respective performances. To validate the generalizability of the developed approach, it is further used in the wind speed forecasting of another typhoon wind speed dataset. The satisfactory performance demonstrates the effectiveness of the developed approach for multi-step wind speed forecasting of tropical storms.

Tao Ma, Huabo Xiao, Yonghang Yang

The landslide displacement in the Three Gorges Reservoir Area (TGRA) follows a step-like pattern, making the evolutionary stage difficult to predict. An optimized transfer learning model integrating a convolutional neural network (CNN) and bidirectional long short-term memory (BiLSTM) is proposed for predicting the evolutionary stage of displacement. The Bayesian algorithm is used to optimize hyperparameters of the models. The CNN-BiLSTM-Bayesian model first trains a deep learning model based on the source domain (the Baishuihe landslide). Then, transfer learning techniques and parameter fine-tuning are applied to transfer knowledge from the Baishuihe landslide to the target domain (the Bazimen landslide). The results show that the CNN-BiLSTM-Bayesian model is better than other models, such as BiLSTM and gated recurrent unit (GRU). Compared with BiLSTM, the F1-score and area under the curve (AUC) of the proposed model improved by 4.94% and 4.88% for the Baishuihe landslide, respectively. The CNN layer can extract features of data, and the BiLSTM layer can capture temporal information within displacement data. The proposed model not only acquires knowledge from similar landslide cases but also has excellent accuracy despite limited new data. Therefore, the optimized transfer learning model can accurately predict the evolutionary stage and provide a reference for landslide assessment.

Katarzyna Krawczyk, Barbara Pilch-Pitera, Michał Kędzierski et al.

Abstract In this work, silver-free, low-temperature-curing epoxy powder coatings with antimicrobial functionality were developed. The cationic biopolymer ε-polylysine (PLY) in its protonated form, as well as its intercalation and co-intercalation products with aminododecanoic acid (ADA) in montmorillonite (MMT), were employed as environmentally friendly bioactive additives. The powder coatings were formulated using epoxy resin and a highly reactive phenolic curing agent and subsequently applied onto steel substrates. The resulting materials were comprehensively characterized in terms of surface morphology, gloss, hardness, adhesion, and wettability. The coating showed a water contact angle of approximately 85°and an antibacterial reduction exceeding 99% against E. coli and S. aureus under laboratory conditions (ISO 22196). Antimicrobial activity is most likely associated with electrostatic interaction between the cationic PLY and bacterial membranes. Overall, this study suggests a promising and sustainable, silver-free strategy for developing antimicrobial powder coatings that may be suitable for hygiene sensitive environments, pending further long-term and safety evaluation.

Chunjiang Yu, Tao Li, Weiyu Dou et al.

The method addresses the challenges of non-steady conditions at an early age by combining wavelet filtering and empirical mode decomposition (EMD) to separate strain components arising from shrinkage, expansive agent compensation, temperature variations, construction disturbances, and live loads. The approach incorporates construction logs as external constraints to ensure accurate correspondence between signal features and physical events. Scientifically, this study addresses the fundamental problem of identifying and quantifying multi-source strain components under transient and non-steady construction conditions, which remains a major challenge in the field of structural monitoring. Field monitoring was conducted on typical cast-in-place concrete components: a full-width bridge deck in the negative moment region. The results show that both structural types exhibit a distinct shrinkage–recovery process at an early age but differ in amplitude distribution, recovery rate, and restraint characteristics. During the construction procedure stage, the cast-in-place segment in the negative moment region was sensitive to prestressing and adjacent segment construction. Under variable loads, the former showed higher live load sensitivity, while the latter exhibited more pronounced temperature-driven responses. Total strain decomposition revealed that temperature and dead load were the primary long-term components in the structure, with differing proportional contributions. Representative strain variations observed in the field ranged from 10 to 50 µε during early-age shrinkage–expansion cycles to 80–100 µε reductions during prestressing operations, quantitatively illustrating the evolution characteristics captured by the proposed method. This approach demonstrates the method’s capability to reveal transient stress mechanisms that conventional steady-state analyses cannot capture, providing a reliable basis for strain monitoring, disturbance identification, and performance evaluation during construction, as well as for long-term prediction and optimization of operation–maintenance strategies.

D. Gao, Z. Deng, Wenhan Yang et al.

Abstract Two vortex-induced vibration (VIV) events of the main girder of long-span bridges successively happened on the Yingwuzhou suspension bridge and Humen suspension bridge in China, 2020, and drew public attention. Especially for the Humen suspension bridge, the amplitude of VIV was so notable that the traffic was closed for 10 days. Generally, VIV is sensitive to the structural and ambient issues and large-amplitude VIV is unacceptable for engineering structures as it could result in potential fatigue failure of some key joint components. Therefore, it is of great significance to explore the excitation mechanism of VIV and develop effective methods to mitigate excessive vibration of main-girders. From the perspective of vortex dynamics, we present a selective review of recent progress on the mechanism of VIV occurred in long-span bridges and aerodynamic countermeasures to attenuate the VIV amplitude. Notwithstanding the VIV mechanism of girders has not been thoroughly clarified, it is generally accepted that VIV rises from the unsteady vortex shedding from the main girder. Besides, the flow control methods, which are proposed to manipulate the surrounding flow patterns around the girder, are also focused in this review. Some perspectives are finally presented for future studies in fluid–structure interaction and aerodynamic vibration mitigation of long-span bridges.

Q. Han, Zhenyue Jia, Kun Xu et al.

Abstract Seismic resilient structures with low structural damage and self-centering behavior after an earthquake are focus issues of current earthquake engineering. Unbonded pretensioned rocking columns offer advantages for accelerated bridge construction in seismic regions, which utilize column-uplifting mechanisms, high strength post-tensioning, and replaceable energy dissipation devices to enhance seismic performance and resilience. The experiment of three 1:3 scale unbonded, post-tensioned rocking bridge bents with different types of external replaceable energy dissipation devices subjected to quasi-static loading protocols, were carried out according to practical engineering demand in high-intensity earthquake regions. An improved analytical model was proposed for predicting the force-displacement relationship of the post-tensioned rocking bridge bent systems considering the neutral axis depth. Minimal physical damage was observed for the post-tensioned rocking bridge bent systems, which exhibit good energy dissipation and self-centering behavior. Especially, the external replaceable buckling-restrained plates dissipaters can be easily replaced if severely damaged subjected to higher than expected ground motions. The satisfactory analytical and experimental comparisons are presented as a validation of the reliability for the high-performance seismic-resistant bridge bent systems and the modelling techniques in this study.

YUAN Dong, XIAO Kun

Objective  With the relocation of major national strategic plans to western China, railway construction has gradually focused on the complex and dangerous mountainous regions of Yunnan, Sichuan, and Xizang Provinces, where the proportion of tunnels along the railway is very high. When a tunnel passes through a water-rich fault fracture zone, the rock mass in front of the palm face is prone to hydraulic fracturing and damage under high osmotic pressure, leading to disasters such as rock collapse and water inrush.   Methods  The wing crack model is introduced to fully account for the initiation and propagation of secondary wing cracks in water-saturated fractures, as well as the impact of excavation disturbances. The effective tensile stress and rock bridge size between intermittent fractures in the rock are revised. The tensile-shear failure mechanism of the water-insulating rock mass in front of the tunnel face is analyzed, and the critical water pressure for hydraulic fracturing of the water-insulating rock mass is derived. The minimum safety thickness for the tunnel face against water inrush in the proximity of a fault fracture zone is proposed.   Results  The theoretical formulas indicate that the anti-splitting thickness of the water-insulating rock mass is related to factors such as tunnel section size, fault water pressure, excavation disturbance, in-situ stress, rock mass strength, crack size, and fracture parameters. Through analysis of the sensitivity of the different influencing factors, it is found that the anti-splitting thickness of the rock mass increases with the increase of the tunnel section size, the fault water pressure, and the excavation disturbance factor, but decreases with the increase of the vertical tunnel stress and the rock mass strength. At the same time, the excavation disturbance damage has the most significant impact on the calculated anti-splitting thickness of the rock mass.   Conclusion  In practical engineering, there are certain empirical judgments and errors in obtaining excavation disturbance factors via rock integrity assessment and rock wave velocity testing. Therefore, this method requires accurate acquisition of the damage conditions of the rock mass in front of the tunnel face. Various assessment methods can be used for comparison and selection, and a conservative approach can be adopted by using a larger value for the excavation disturbance factor.   Significance  Finally, taking a tunnel in western Sichuan near the Yalahe fault as an example and considering the actual engineering disturbance and fault water pressure, the minimum safety thickness of the rock wall at the tunnel face is calculated to verify the engineering applicability of the proposed method. This research can effectively guide on-site risk prediction and plan formulation; it provides a theoretical basis for the prevention and control of water inrush in tunnels crossing water-rich fault fracture zones.

Jun Yang, Jingchen Leng, Jianting Zhou et al.

Abstract Bridge widening involves phased construction of adjacent structures to maintain uninterrupted traffic flow. This process exposes freshly placed longitudinal joints between staged deck constructions to vehicle-induced vibrations, potentially compromising their mechanical integrity. This study investigates the flexural behavior of ultra-high-performance concrete (UHPC) longitudinal joints under such vibrations through model tests. To simulate actual site conditions, we developed a novel vibration test setup that replicates the dynamic environment experienced by these joints during construction. Micro- and meso-scale tests were conducted to examine the flexural behavior of longitudinal joints following vibration exposure. Results revealed that vibration amplitude significantly influences fiber orientation and flexural strength of ultra-high-performance concrete (UHPC) wet joint specimens. Low-amplitude vibrations (3 Hz at 1 mm and 3 mm) enhanced fiber orientation, increasing flexural strength by 11.5% to 19.8% and ultimate load capacity by 17% compared to non-vibrated specimens. Conversely, high-amplitude vibrations (3 Hz at 5 mm) adversely affected fiber orientation, decreasing flexural strength by 23.9% and ultimate load capacity by 19% relative to non-vibrated specimens.

Jianping Song, Baojun Li, Lingcai Kong et al.

As one of the most innovative cement-based materials, ultra-high performance concrete (UHPC), with excellent durability and mechanical properties, has been widely used in strengthening existing bridges. In this study, in-situ four-point bending tests were carried out to investigate the flexural behavior of precast reinforced concrete (RC) hollow slab beams in service for 15 years strengthened with UHPC. Among them, three hollow slab beams were strengthened with UHPC, and the interface treatment was chiseling, planting rebars, and a combination of chiseling and planting rebars, respectively. The remaining one without any strengthening treatment was used as the control specimen. To evaluate the enhancement effect of different interface treatments on UHPC-strengthened beams, the cracking load, ultimate load, crack development and failure modes of UHPC-strengthened beams were analyzed. Results indicated that the stiffness, deflection capacity and flexural capacity of UHPC-strengthened beams was significantly improved. Meanwhile, the stiffness of UHPC-strengthened beams in the pre-damage stage was increased by 49%–94%, when compared with the unstrengthened beam. Correspondingly, the ultimate flexural capacity was increased by 29%–38%. The interface chiseling treatment was more favorable to enhance the deformation capacity of UHPC-strengthened beams. The interface planting rebar treatment was more favorable to enhancing the ductility of UHPC-strengthened beams. The crack development was effectively suppressed by the interface chiseling and planting rebars together. This contributes to a higher load capacity reserve for UHPC-strengthened beams. The bearing capacity under serviceability limit state of the UHPC-strengthened beams was increased by 1.25, 2, and 2.5 times through the interface treatments of chiseling, planting rebars, and a combination of both, respectively.

Han Li, Shengze Tian, Xinzhi Dang

Unbonded steel-mesh-reinforced rubber bearings (USRBs) have been proposed as an alternative isolation bearing for small-to-medium-span highway bridges. It replaces the steel plate reinforcement of common unbonded laminated rubber bearings (ULNR) with special steel wire meshes, resulting in improved lateral properties and seismic performance. However, the impact of this novel steel wire mesh reinforcement on the ultimate compression capacity of USRB has not been studied. To this end, theoretical and experimental analysis of the ultimate compression capacity of USRBs were carried out. The closed-form analytical solution of the ultimate compression capacity of USRBs was derived from a simplified USRB model employing elasticity theory. A parametric study was conducted considering the geometric and material properties. Ultimate compression tests were conducted on 19 USRB specimens to further calibrate the analytical solution, considering the influence of the number of reinforcement layers. An efficient solution for USRBs’ ultimate compression capacity was obtained via multilinear regression of the calibrated analytical results. The efficient solution can simplify the estimation of USRBs’ ultimate compression capacity while maintaining the same accuracy as the calibrated solution. Based on the efficient solution, the design process of a USRB with a specific ultimate compression capacity was illustrated.

Renwei Zhang, Liqun Zheng, Hai Zhong et al.

Investigating the seismic behavior of precast concrete bridge piers is crucial in the design process due to the complex stress distribution in the connecting components. To demonstrate the seismic behavior of precast concrete bridge piers with hybrid joint connections, three bridge piers were designed with a scaling ratio of 1:8 and then tested under low cyclic loading conditions. The tests involved varying shapes of steel tube connection keys as parameters. This study involved examining failure modes and crack development, as well as analyzing the hysteretic performance, deformation capacity, energy dissipation, and stiffness degradation of the specimens. Furthermore, a finite element model was developed using ABAQUS, and the validity of the modeling approach suggested in this study was confirmed through tests. The results indicate that the precast piers exhibit reduced concrete damage at the joints. The enhanced strength of the joints is attributed to the incorporation of steel tube connection keys. The circular steel tube connection key integrated into the precast bridge pier offers a superior bearing capacity, energy dissipation, and stiffness degradation compared to the cross-shaped steel tube connection key. The presence of the built-in circular steel tube connection key in the precast bridge pier suggests that it complies with the seismic structural measures and is consistent with the design principle of “strong joint and weak member”.

Yongshun Xu, Ming Chi, Heap-Yih Chong et al.

Building information modeling (BIM) and blockchain applications have introduced significant benefits to the architecture, engineering, construction, and operation (AECO) industry in recent years. Although publications on BIM and blockchain integration have been increasing, no systematic examination of the present status and managerial implications of integrated BIM and blockchain has been conducted. To bridge this gap, this paper conducts a state-of-the-art review of the development of integrated BIM and blockchain in a built environment. A combination of qualitative and quantitative methods was adopted to synthesize and analyze the research evidence. The results revealed five key managerial implica­tions of BIM integration with blockchain at the project level: design and collaboration, financial management, construction management, information management, and integration management (with other cutting-edge technologies). Challenges and opportunities are outlined and articulated from both technological and managerial perspectives, such as stakeholder management, impact assessment, real-time project management, information redundancy, and incompatibility.

A. Neves, I. González, J. Leander et al.

As civil engineering structures are growing in dimension and longevity, there is an associated increase in concern regarding the maintenance of such structures. Bridges, in particular, are critical links in today’s transportation networks and hence fundamental for the development of society. In this context, the demand for novel damage detection techniques and reliable structural health monitoring systems is currently high. This paper presents a model-free damage detection approach based on machine learning techniques. The method is applied to data on the structural condition of a fictitious railway bridge gathered in a numerical experiment using a three-dimensional finite element model. Data are collected from the dynamic response of the structure, which is simulated in the course of the passage of a train, considering the bridge in healthy and two different damaged scenarios. In the first stage of the proposed method, artificial neural networks are trained with an unsupervised learning approach with input data composed of accelerations gathered on the healthy bridge. Based on the acceleration values at previous instants in time, the networks are able to predict future accelerations. In the second stage, the prediction errors of each network are statistically characterized by a Gaussian process that supports the choice of a damage detection threshold. Subsequent to this, by comparing damage indices with said threshold, it is possible to discriminate between different structural conditions, namely between healthy and damaged. From here and for each damage case scenario, receiver operating characteristic curves that illustrate the trade-off between true and false positives can be obtained. Lastly, based on the Bayes’ Theorem, a simplified method for the calculation of the expected total cost of the proposed strategy, as a function of the chosen threshold, is suggested.

Yanhai Yang, Liang Yue, Ye Yang et al.

The road performance decay law of EACRM under freeze-thaw cycles was studied using laboratory tests on the macroscopic scale in order to comprehensively analyze the serious performance damage mechanism of emulsified asphalt cold recycled mixture (EACRM) in cold regions during the service period. The surface cracking behavior, internal void evolution characteristics, and asphalt mortar morphology damage of EACRM under freeze-thaw cycles were studied by means of digital speckle, industrial CT, and scanning electron microscope (SEM) on the mesoscopic and microscopic scale. The results show that along with the increase in the number of freeze-thaw cycles, the road performance of EACRM decreases significantly. The surface of EACRM obviously cracks, and the width and number of main cracks increase significantly. The fatigue times of the maximum horizontal strain in the whole field gradually decrease. Air voids and the average volume of meso-void visibly increase. The microcracks of cement-emulsified asphalt mortar constantly emerge at the interface. The serious damage of the “three-dimensional network structure” is the fundamental reason for the performance decay of EACRM in cold regions. The performance damage of EACRM in cold regions is aggravated by water seeping into voids from cracks. Eventually, EACRM shows serious freeze-thaw inflicted damage.

Zhi-Xuan Ren, Xiao-Xiong Zeng, Yi-Wen Han et al.

In consideration of the thermodynamic pressure and volume, we present a short and direct derivation of Hawking radiation as a tunneling process for the charged particles. Using Parikh's Semi-classical tunneling method and Lagrangian analysis on the action, we provide the geodesic equation of the massive particles via tunneling from the Anit-de Sitter (AdS) black hole. Special attention is given to calculating the imaginary part before and after particles via the horizon as the pressure and volume are considered. The result shows that the emission rates are always related to the change of Bekenstein-Hawking entropy and the exact spectrum is not precisely thermal, which are consistent with the case without pressure and volume.

Run SHI, Jiayu LI, Minghao CHEN et al.

Restricted by the surface smoothness and topography, it is impossible for some high-speed railways on mountainous regions to avoid parts of rockfall development sections, posing great safety challenges to construction projects and railway operations. In light of that, this paper laid its focus on the rockfall situated by the entrance of Xinghuayu Tunnel along the proposed Jinan-Zaozhuang Railway project, and leveraged the power of drone-captured 3D aerial photography to perform digital geological survey and mapping so as to accurately identify the development characteristics, scale, as well as modes of deformation and failure of said rockfall. Next, by cross-referencing the results of 3DEC numerical simulation with those from analytic hierarchy process (AHP), color-coded maps highlighting the scope of influence and danger levels of potential rockfalls induced were obtained. Using said maps, zone-by-zone hazard and risk assessment were then performed, based on which corresponding prevention and control measures were put forward. The findings show that among the 12 dangerous rock belts identified from the drone-captured 3D aerial photography model, only Belt No. 5 would threaten the safety of the tunnel entrance and bridge abutments, for which the combination of anti-rockfall passive protective netting and an open-cut tunnel structure was recommended as a comprehensive solution. By virtue of the solution’s effectiveness, this study can offer reliable references for not only zone-by-zone hazard and risk assessment for rockfalls, but also railway route selection and disaster prevention and mitigation.