scholarly journals Bridge failures, forensic structural engineering and recommendations for design of robust structures

2021 ◽  
Vol 73 (07) ◽  
pp. 717-737
Keyword(s):  
Structural Engineering ◽  
Human Factor ◽  
Progressive Collapse ◽  
Real Life ◽  
Design Guidelines ◽  
Structural Failure ◽  
Failure Data ◽  
Sequence Of Events ◽  
Detailed Statistical Analysis ◽  
Bridge Failure

A review of forensic structural engineering, which is a strategy that follows after bridge failure, is presented in the paper. A detailed statistical analysis, and worldwide systematisation of available bridge failure data for the 1966-2020 period, are given. More than six hundred cases of partial or full collapse of bridges are analysed in detail, and causes that have led to their failure are examined. Failure of each of these bridges was in most cases not caused by a single factor, i.e. the main cause was most often just a trigger in the cause-and-effect sequence of events that contributed to such failure. Consequently, in addition to main causes, the influence of human factor, as a precondition leading to failure, is considered in each of the analysed cases. Types of progressive collapse, being a critical structural failure mechanism, are described in the second part of the paper, with an emphasis on bridges. An overview of the theory of structural robustness is also given. Design guidelines and approaches, aimed at preventing catastrophic failure and creating more robust structures, are presented. Methods for achieving robustness in the design of new bridges and in the strengthening of the existing ones are also described, and practical real-life examples are provided.

scholarly journals A Framework for Research in Gamified Mobile Guide Applications using Embodied Conversational Agents (ECAs)

2015 ◽  
Vol 2 (3) ◽  
Author(s):  
Ioannis Doumanis ◽  
Serengul Smith
Keyword(s):  
Real Life ◽  
Design Guidelines ◽  
Location Based Services ◽  
Mobile Technologies ◽  
Conversational Agents ◽  
Cultural Narratives ◽  
Unified Framework ◽  
Research Framework ◽  
Player Experience ◽  
Cognitive Accessibility

Mobile Guides are mobile applications that provide players with local and location-based services (LBS), such as navigation assistance, where and when they need them most. Advances in mobile technologies in recent years have enabled the gamification of these applications, opening up new opportunities to transfer education and culture through game play. However, adding traditional game elements such as PBLs (points, badges, and leaderboards) alone cannot ensure that the intended learning outcomes will be met, as the player’s cognitive resources are shared between the application and the surrounding environment. This distribution of resources prevents players from easily immersing themselves into the educational scenario. Adding artificial conversational characters (ECAs) that simulate the social norms found in real-life human-to-human guide scenarios has the potential to address this problem and improve the player’s experience and learning of cultural narratives [1]. Although significant progress has been made towards creating game-like mobile guides with ECAs ([2], [3]), there is still a lack of a unified framework that enables researchers and practitioners to investigate the potential effects of such applications to players and how to approach the concepts of player experience, cognitive accessibility and usability in this context. This paper presents a theoretically-well supported research framework consisted of four key components: differences in players, different features of the gamified task, aspects of how the ECA looks, sound or behaves and different mobile environments. Furthermore, it provides based on this framework a working definition of what player experience, cognitive accessibility and usability are in the context of game-like mobile guide applications. Finally, a synthesis of the results of six empirical studies conducted within this research framework is discussed and a series of design guidelines for the effective gamification of mobile guide applications using ECAs are presented. Results show that an ECA can positively affect the quality of the player’s experience, but it did not elicit better player retention of cultural narratives and navigation of routes.

Who is Isaiah's Servant? Narrative identity and theological potentiality

2008 ◽  
Vol 61 (2) ◽  
pp. 125-136 ◽  
Author(s):  
Mark Gignilliat
Keyword(s):  
Narrative Identity ◽  
Real Life ◽  
The Self ◽  
Divine Action ◽  
Sequence Of Events ◽  
Unique Member ◽  
Divine Identity ◽  
Over Time

AbstractThe question ‘Who is the Servant?’ is one which remains a debated topic among many interpreters of Isaiah 40–55. This article seeks to address the same question with the aid and perspective of narrative identity. Narrative identity, as explicated by Ricoeur and Frei, is a means of understanding a character within a literary plot, or real life, as displayed in a narrated sequence of events. A person's identity, especially within literature, is the constancy of the self in the tortuous events of a narrated sequence over time. This article seeks to adjudicate the question of the Servant's identity by observing the character of the Servant within the plot of Isaiah 40–55. The conclusion drawn is that the Servant is the unique means of God's reconciliation of both Zion and the nations. Also, the divine action and description of YHWH and the Servant begin to bleed in such a way that the Servant can be described as a unique member of the divine identity.

Developments in Structural Optimization and Applications to Intelligent Structural Vibration Control

2007 ◽  
pp. 101-121 ◽  
Author(s):  
Faruque Ali ◽  
Ananth Ramaswamy
Keyword(s):  
Vibration Control ◽  
Control Systems ◽  
Intelligent Control ◽  
Structural Control ◽  
Structural Engineering ◽  
Real Life ◽  
Fuzzy Rule ◽  
Structural Vibration ◽  
Rule Base ◽  
The Subject

The chapter introduces developments in intelligent optimal control systems and their applications in structural engineering. It provides a good background on the subject starting with the shortcomings of conventional vibration control techniques and the need for intelligent control systems. Description of a few basic tools required for intelligent control such as evolutionary algorithms, fuzzy rule base, and so forth, is outlined. Examples on vibration control of benchmark building and bridge under seismic excitation are presented to provide better insight on the subject. The chapter provides necessary background for a reader to work in intelligent structural control systems with real-life examples. Current trends in the research area are given and challenges put forward for further research.

scholarly journals Quantification of Dynamic Excitation Potential of Pedestrian Population Crossing Footbridges

2011 ◽  
Vol 18 (4) ◽  
pp. 563-577 ◽  
Author(s):  
Stana Žcaronivanović ◽  
Aleksandar Pavić
Keyword(s):  
Real Life ◽  
Vertical Direction ◽  
Design Guidelines ◽  
Vibration Response ◽  
Step Frequency ◽  
Response Level ◽  
Dynamic Excitation ◽  
Excitation Potential ◽  
Vibration Serviceability ◽  
Single Response

Due to their slenderness, many modern footbridges may vibrate significantly under pedestrian traffic. Consequently, the vibration serviceability of these structures under human-induced dynamic loading is becoming their governing design criterion. Many current vibration serviceability design guidelines, concerned with prediction of the vibration in the vertical direction, estimate a single response level that corresponds to an "average" person crossing the bridge with the step frequency that matches a footbridge natural frequency. However, different pedestrians have different dynamic excitation potential, and therefore could generate significantly different vibration response of the bridge structure. This paper aims to quantify this potential by estimating the range of structural vibrations (in the vertical direction) that could be induced by different individuals and the probability of occurrence of any particular vibration level. This is done by introducing the inter- and intra-subject variability in the walking force modelling. The former term refers to inability of a pedestrian to induce an exactly the same force with each step while the latter refers to different forces (in terms of their magnitude, frequency and crossing speed) induced by different people. Both types of variability are modelled using the appropriate probability density functions. The probability distributions were then implemented into a framework procedure for vibration response prediction under a single person excitation. Instead of a single response value obtained using currently available design guidelines, this new framework yields a range of possible acceleration responses induced by different people and a distribution function for these responses. The acceleration ranges estimated are then compared with experimental data from two real-life footbridges. The substantial differences in the dynamic response induced by different people are obtained in both the numerical and the experimental results presented. These results therefore confirm huge variability in different people's dynamic potential to excite the structure. The proposed approach for quantifying this variability could be used as a sound basis for development of new probability-based vibration serviceability assessment procedures for pedestrian bridges.

On the Estimation of Failure Rates of Multiple Pipeline Systems

2006 ◽  
Author(s):  
F. Caleyo ◽  
L. Alfonso ◽  
J. A. Alca´ntara ◽  
J. M. Hallen ◽  
F. Ferna´ndez Lagos ◽  
...  
Keyword(s):  
Stochastic Model ◽  
Oil And Gas ◽  
Statistical Tests ◽  
Real Life ◽  
Intensity Function ◽  
Model Parameters ◽  
Repairable Systems ◽  
Failure Data ◽  
Pipeline Systems ◽  
Failure Intensity

In this work, the statistical methods for the reliability of repairable systems have been used to produce a methodology capable to estimate the annualized failure rate of a pipeline population from the historical failure data of multiple pipelines systems. The proposed methodology provides point and interval estimators of the parameters of the failure intensity function for two of the most commonly applied stochastic models; the homogeneous Poisson process and the power law process. It also provides statistical tests to assess the adequacy of the stochastic model assumed for each system and to test whether all systems have the same model parameters. In this way, the failure data of multiple pipeline systems are only pooled to produce a generic failure intensity function when all systems follow the same stochastic model. This allows addressing both statistical and tolerance uncertainty adequately. The proposed methodology is outlined and illustrated using real life failure data of multiple oil and gas pipeline systems.

Automation of emergency response management group operation at major pipeline facilities

2020 ◽  
Vol 10 (1) ◽  
pp. 106-114
Author(s):  
Vitaly V. Stepanov ◽  
◽  
Eldar А. Isaev ◽  
Denis I. Stavitsky ◽  
◽  
...  
Keyword(s):  
Information System ◽  
Emergency Response ◽  
Human Factor ◽  
Far East ◽  
Real Life ◽  
Data Retrieval ◽  
Petroleum Products ◽  
Management Group ◽  
Management Groups ◽  
Major Pipeline

The efficiency of actions of emergency response personnel at major pipeline facilities is a key factor in minimizing accident consequences. In this paper the authors analyze command post exercises aimed at preparing for emergency responses (oil and petroleum products spill) with personnel working at Transneft enterprises. Shortcomings in organizing the operation of emergency response management groups have been identified. The main ones are as follows: lack of proper interaction and the necessary concurrence of actions of management group representatives; no algorithm for preparing reports and hence the failure to meet deadlines for submitting such reports to regulatory authorities. To some extent, these deficiencies have been minimized through the development and implementation of emergency reporting logs in routine practices of management groups. However, many processes have still been highly dependent on the human factor leading to errors, and the emergence and spread of false and contradictory information in the course of emergency response activities. An appropriate automated information system has been designed in order to minimize the effect of the human factor in organizing the work of emergency response management groups. The article presents its model, describing the algorithm of its operation and functionality. The system was introduced into production at Transneft Far East, LLC and was highly effective in terms of quality of document processing, optimizing time spent on report completion and submission, organizing data retrieval, and monitoring emergency response actions. The application of the developed information system has significantly reduced the number of demerits related to organizing the work of emergency response management groups. The system is unique in Russia: it can be used in real-life emergencies or for training personnel to act using the system’s training mode.

Crashworthiness of Aluminum Structures

1999 ◽  
Author(s):  
A. S. Warren ◽  
M. J. Wheeler
Keyword(s):  
Progressive Collapse ◽  
Local Buckling ◽  
Design Guidelines ◽  
Structural Members ◽  
General Rules ◽  
Basic Work ◽  
Work Of Deformation ◽  
Energy Absorbing ◽  
High Level ◽  
Aluminum Material

Abstract There is a growing recognition by the auto makers of the benefits of aluminum for vehicle structures. While there is now no doubt that the structural demands of vehicles can be met with aluminum, it is less well appreciated that such structures can also be designed to provide a high level of crashworthiness. This paper summarizes the basic work that has been carried out to demonstrate and quantify the behavior and energy absorption of aluminum vehicle structures under impact collapse conditions. Aluminum, like steel, collapses under high load conditions by folding and the resulting work of deformation absorbs the vehicle’s kinetic energy. It follows that most of the general rules for designing crashworthy structures in steel, in terms of ensuring progressive collapse, avoiding premature bending failures, and transferring load as the collapse event proceeds, apply equally well to aluminum structures. There are, however, differences from steel due to the greater thickness of aluminum material used. This increases resistance to local buckling, and results in larger volumes of the material becoming involved in the energy absorbing collapse events. There are other material characteristics that have a bearing on developing crashworthy aluminum structures, and the paper covers the more significant material and related design guidelines that should be followed in the development of the main energy absorbing structural members in vehicle structures. Finally, reference is made to results from NHTSA’s NCAP program for appraising the crashworthiness of new vehicles. These have demonstrated in a very practical way the excellent crashworthiness of vehicles with well designed aluminum structures.

Analogies Between Coupled-Mode Gate Vibration and Coupled-Mode Flutter

2017 ◽  
pp. 565-592
Keyword(s):  
Design Guidelines ◽  
Frequency Mode ◽  
Suspension Bridges ◽  
Two Dimensional ◽  
Mode Instability ◽  
Dynamic Design ◽  
Coupled Mode ◽  
Dynamic Excitation ◽  
Bridge Failure ◽  
Tacoma Narrows Bridge

In this chapter the similarities between the Tacoma Narrows Bridge failure in 1940 and the Folsom Dam gate failure in 1995 are examined. In both cases, static design guidelines were followed in the design of the structure under the assumption that large, massive structures would not be susceptible to dynamic excitation. Fundamentals of two-dimensional coupled mode flutter are presented. The frequency mode coalescence that occurs in two-dimensional flutter is noted. It is seen to have some resemblance to the mode-coupling in the coupled-mode instability of Tainter gate. The need for development of dynamic design guidelines for Tainter gates is argued to be parallel to the need for dynamic design guidelines for suspension bridges in the wake of the Tacoma Narrows failure.

On the Estimation of Failure Rates of Multiple Pipeline Systems

2008 ◽  
Vol 130 (2) ◽  
Author(s):  
F. Caleyo ◽  
L. Alfonso ◽  
J. Alcántara ◽  
J. M. Hallen
Keyword(s):  
Stochastic Model ◽  
Oil And Gas ◽  
Statistical Tests ◽  
Real Life ◽  
Intensity Function ◽  
Model Parameters ◽  
Repairable Systems ◽  
Failure Data ◽  
Pipeline Systems ◽  
Failure Intensity

In this work, the statistical methods for the reliability of repairable systems have been used to produce a methodology capable to estimate the annualized failure rate of a pipeline population from the historical failure data of multiple pipeline systems. The proposed methodology provides point and interval estimators of the parameters of the failure intensity function for two of the most commonly applied stochastic models: the homogeneous Poisson process and the power law process. It also provides statistical tests for assessing the adequacy of the stochastic model assumed for each system and testing whether all systems have the same model parameters. In this way, the failure data of multiple pipeline systems are only merged in order to produce a generic failure intensity function when all systems follow the same stochastic model. This allows statistical and tolerance uncertainties to be addressed adequately. The proposed methodology is outlined and illustrated using real-life failure data of oil and gas pipeline systems.

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