Safety assessment method of steel protective structure against large-scale debris flow

2021 ◽  
pp. 204141962110595
Author(s):  
Hiroshi Kokuryo ◽  
Toshiyuki Horiguchi ◽  
Nobutaka Ishikawa
Keyword(s):  
Debris Flow ◽  
Safety Assessment ◽  
Large Scale ◽  
Assessment Method ◽  
Load Level ◽  
Energy Constant ◽  
Level Ii ◽  
Load Carrying ◽  
Torrential Rainfall ◽  
Protective Structures

Recently, steel pipe open type protective structures (steel open dams) have been damaged because of large-scale debris flow resulting from torrential rainfall based on abnormal climate. This article proposes a safety assessment method for the load-carrying capacity of a steel open dam against large-scale debris flow load (level II load) using the energy constant law. First, the safety assessment method of steel open dams is proposed that the ultimate strength must be larger than the required strength against the level II load, which is determined by using the energy constant law. Second, the load-carrying capacities of three types of steel open dams with different structural shapes against the front and eccentric debris flow loadings are investigated by a push-over analysis. Finally, the safety assessments on load-carrying capacities against the front and eccentric debris flow loading are confirmed and the strength reduction by the eccentric loading is examined for three steel open dams.

Failure analysis of steel open dam against an extreme boulder debris flow

2020 ◽  
pp. 204141962097056
Author(s):  
Toshiyuki Horiguchi ◽  
Hiroshi Kokuryo ◽  
Nobutaka Ishikawa
Keyword(s):  
Debris Flow ◽  
Failure Analysis ◽  
Safety Assessment ◽  
Distinct Element ◽  
Rigid Wall ◽  
Reduction Factor ◽  
Second Step ◽  
Uniform Load ◽  
Load Model ◽  
Level Ii

This paper presents a failure analysis for a steel open-type Sabo dam (hereafter, steel open dam) against an extreme boulder debris flow load (hereafter, level II load) by a two-step analysis. The first step analysis is to estimate the level II load against the rigid wall by using the revised distinct element method (DEM). In the second step, the failure mechanism of a steel open dam is examined by using a dynamic elastic plastic analysis, in which the level II load-time relations obtained by the first analysis are multiplied by a reduction factor and then used. For the second step, the effects of the flange joint and dent deformation of the connection between column and beam are considered. Finally, a simple entire uniform load onto the steel open dam is proposed as a level II load model for the safety assessment.

scholarly journals Transient Analysis and Safety Assessment of Turbofan Engine Structures during Bird Ingestion

2020 ◽  
Vol 2020 ◽  
pp. 1-17
Author(s):  
Gang Luo ◽  
Chi Ma ◽  
Wei Chen ◽  
Lulu Liu ◽  
Zhenhua Zhao
Keyword(s):  
Transient Analysis ◽  
Safety Assessment ◽  
Safety Analysis ◽  
Assessment Method ◽  
Dynamic Responses ◽  
Structural Safety ◽  
Turbofan Engine ◽  
Load Carrying ◽  
Large Bird ◽  
Bypass Ratio

The high bypass ratio turbofan engine’s load-carrying structure transient response during bird ingestion was analyzed in accordance with the engine bird ingestion certification regulations, the principles of structural safety assessment were represented, and the structural safety analysis and assessment method of Turbo-Fan engine during bird ingestion were proposed. A high bypass ratio turbofan engine’s FEM was established and verified the rationality when its’ operation. Large bird ingestion into an engine’s procedure was conducted, the dynamic responses of key components on engine’s load-carrying structures during the bird ingestion were discussed, and the safety assessment consequence was obtained. We draw a conclusion that the relevant analysis/simulation data could be submitted to engine certification administration as key documents, the structural safety analysis and assessment method of turbofan engine due to bird ingestion could be applied as analysis and prediction work in the engine bird ingestion certification.

scholarly journals Research Progress of Initial Mechanism on Debris Flow and Related Discrimination Methods: A Review

2021 ◽  
Vol 9 ◽  
Author(s):  
Jun Du ◽  
Zhong-jie Fan ◽  
Wen-tao Xu ◽  
Lin-yao Dong
Keyword(s):  
Debris Flow ◽  
Large Scale ◽  
Numerical Models ◽  
Soil Mass ◽  
Assessment Method ◽  
Research Progress ◽  
Two Phase ◽  
Indicator Method ◽  
Technical Limitation ◽  
Debris Flow Initiation

The initial of debris flow can be classified into two types based on their triggering positions, that is, debris flow from slope and debris flow from gully or channel. For the former, great progress has been achieved on the mechanisms of soil failure and liquefaction. The framework established by a series of theories or laws, such as the Mohr–Coulomb criteria, the unsaturated soil mechanics, and the critical state of soil mass, has been used widely in industry and research. However, the details and discrimination basis for the transformation process from landslide into debris flow still need to be further clarified. Relatively, debris flow from gully or channel is more complex due to its various mass sources and the diversity of processes. Nevertheless, through a great number of case studies and experimental statistics, people have gradually recognized the influential rule and critical condition of factors from landform, hydrology, and other aspects on debris flow initiation. Furthermore, based on the theories of granular flow, continuum mechanics, and rheological law, some typical event-based scenarios can also be reproduced by different single-/two-phase depth integral/average numerical models. However, some key knowledge on mechanism and application level is still insufficient, such as the erosion and entrainment mechanism of materials from different sources, the boundary tractions and materials exchange, as well as the selection of prediction indicators. Three current discriminated methodologies for debris flow initiation, that is, the safety factor method, the rainfall indicator method, and the comprehensive assessment method, were summarized in this article. Considering the technical limitation of each methodology, it is believed that the establishment or improvement of a unified, stable, and open-access database system for event registration and query, as well as the development of large-scale and high-precision rainfall monitoring, is still regarded as the important aspect of debris flow prevention in the future. In addition, as an economic and efficiency means for obtaining information on potential threats and real-time hazard messages, the multielement method for debris flow is recommended as a long-term reference.

A Novel Safety Assessment Method based on Fault Dependent Matrix

2019 ◽  
Vol 15 (9) ◽  
pp. 2392 ◽  
Author(s):  
Dong Haiyong ◽  
Gu Qingfan ◽  
Wang Guoqing ◽  
Zhai Zhengjun ◽  
Lu Yanhong
Keyword(s):  
Safety Assessment ◽  
Assessment Method

scholarly journals Deformation Inspection and Safety Assessment Method of Buried Flexible Pipeline in Service

2021 ◽  
Vol 1043 (4) ◽  
pp. 042043
Author(s):  
Zhu Xinmin ◽  
Feng Shaokong ◽  
Huang Tao ◽  
Shang Feng ◽  
Yang Lufei
Keyword(s):  
Safety Assessment ◽  
Assessment Method

scholarly journals Development and Validation of a Post-Earthquake Safety Assessment System for High-Rise Buildings Using Acceleration Measurements

Mathematics ◽  
2021 ◽  
Vol 9 (15) ◽  
pp. 1758
Author(s):  
Koji Tsuchimoto ◽  
Yasutaka Narazaki ◽  
Billie F. Spencer
Keyword(s):  
Safety Assessment ◽  
Large Scale ◽  
Model Updating ◽  
Safety Evaluation ◽  
Assessment System ◽  
Shaking Table ◽  
Structural Safety ◽  
High Rise ◽  
Steel Building ◽  
Earthquake Safety

After a major seismic event, structural safety inspections by qualified experts are required prior to reoccupying a building and resuming operation. Such manual inspections are generally performed by teams of two or more experts and are time consuming, labor intensive, subjective in nature, and potentially put the lives of the inspectors in danger. The authors reported previously on the system for a rapid post-earthquake safety assessment of buildings using sparse acceleration data. The proposed framework was demonstrated using simulation of a five-story steel building modeled with three-dimensional nonlinear analysis subjected to historical earthquakes. The results confirmed the potential of the proposed approach for rapid safety evaluation of buildings after seismic events. However, experimental validation on large-scale structures is required prior to field implementation. Moreover, an extension to the assessment of high-rise buildings, such as those commonly used for residences and offices in modern cities, is needed. To this end, a 1/3-scale 18-story experimental steel building tested on the shaking table at E-Defense in Japan is considered. The importance of online model updating of the linear building model used to calculate the Damage Sensitive Features (DSFs) during the operation is also discussed. Experimental results confirm the efficacy of the proposed approach for rapid post-earthquake safety evaluation for high-rise buildings. Finally, a cost-benefit analysis with respect to the number of sensors used is presented.

An Online Quantified Safety Assessment Method for Train Service State Based on Safety Region Estimation and Hybrid Intelligence Technologies

2015 ◽  
Vol 25 (03) ◽  
pp. 493-511
Author(s):  
Yong Qin ◽  
Shan Yu ◽  
Yuan Zhang ◽  
Limin Jia ◽  
Xiaoqing Cheng
Keyword(s):  
Safety Assessment ◽  
Safety Analysis ◽  
Assessment Method ◽  
Rolling Bearings ◽  
Safety Risk ◽  
Hybrid Intelligence ◽  
Local Mean ◽  
Interval Type ◽  
Service State

Facing the important issues of safety analysis and assessment for the train service state, an online quantified safety assessment method based on the safety region estimation and hybrid intelligence technologies was proposed in this paper. First, the previous researches on the safety analysis and assessment were briefly reviewed for the train itself and its key equipment, and the existential problems were further pointed out. Then, using the safety monitoring data and the safety region estimation theory, a new online safety assessment method with data-driven was put forward, which was followed by a detailed description of the concrete implementation steps including the EMD (Local Mean Decomposition) and EM (Energy Moment) based safety risk evaluation index selection, Interval Type 2 Fuzzy C-Means (IT2FCM) clustering based safety region boundary calculation modeling and safety risk grading. Finally, in order to verify its performance through experiments, the above method was applied in analyzing and evaluating service states of the rolling bearings, the key equipment of the train, on the basis of mass field data. The experimental results indicate that this method is valid.

scholarly journals Assessment of the Deterioration State of Post-Installed Bonded Anchors Using Ultrasonic

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2077
Author(s):  
Oliver Zeman ◽  
Michael Schwenn ◽  
Martin Granig ◽  
Konrad Bergmeister
Keyword(s):  
Maximum Load ◽  
Assessment Method ◽  
Load Level ◽  
Experimental Investigations ◽  
Load History ◽  
Anchor System ◽  
Ultrasonic Methods ◽  
Building Maintenance ◽  
History Of ◽  
Set Up

The assessment of already installed anchorages for a possible exceeding of the service load level is a question that is gaining more and more importance, especially in building maintenance. Bonded anchors are of particular interest here, as the detection of a capacity reduction or load exceedance can cause damage to the concrete-bonded mortar behavior. This article investigates the extent to which ultrasonic methods can be used to make a prediction about the condition of anchorages in concrete and about their load history. A promising innovative assessment method has been developed. The challenges in carrying out the experimental investigations are the arrangement of the transducers, the design of the test set-up and the applicability of direct, indirect or semidirect ultrasonic transmission. The experimental investigations carried out on a test concrete mix and a bonded anchor system show that damage to the concrete structure can be detected by means of ultrasound. The results indicate the formation of cracks and therefore a weakening of the response determined by means of direct, indirect and semidirect ultrasonic transmission. However, for application under non-laboratory conditions and on anchors with unknown load history, the calibration with a reference anchor and the identification of the maximum load is required. This enables a referencing of the other loaded anchors to the unloaded conditions and allows an estimation of the load history of individual anchors.

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