Current State Of Structure Research Articles

Структурный подход к оценке работоспособности системы мониторинга инженерных конструкций вантового моста через Петровский канал в створе автомобильной дороги «Западный скоростной диаметр» в городе Санкт-Петербурге. Часть 2

Purpose: assessing the performance of the monitoring system for engineering structures and assessing the current state of the structures of the cable-stayed bridge across the Petrovsky Canal in the alignment of the Western High-Speed Diameter highway in the city of St. Petersburg due to the occurrence of emergency situations in which accelerometers on the pylons record values exceeding the limit. Methods: statistical data from the databases of the existing system of monitoring engineering structures is used to obtain the results. The tasks, set within the framework of the study, are accomplished by applying the theoretical methods of scientific knowledge: the analytical method, the mathematical statistics theory, induction. Results: the resulting structural approach to assessing the performance of the monitoring system for engineering structures on cable-stayed bridges makes it possible to reduce the number of false alarms of the system and assess the current state of the bridge structure. Within the framework of the III stage of the structural approach, it is proposed to develop a methodology for assessing the performance of the monitoring system for engineering structures with subsequent assessment of the current state of cablestayed bridge structures. Practical significance: the results of the work are important for construction as they expand the understanding of the features of the mechanism of soil freezing.

Структурный подход к оценке работоспособности системы мониторинга инженерных конструкций вантового моста через Петровский канал в створе автомобильной дороги «Западный скоростной диаметр» в г. Санкт-Петербурге. Часть 1

Purpose: assessing the performance of the monitoring system for engineering structures and assessing the current state of the structures of the cable-stayed bridge across the Petrovsky Canal in the alignment of the Western High-Speed Diameter highway in the city of St. Petersburg due to the occurrence of emergency situations in which accelerometers on the pylons record values exceeding the limit. Methods: statistical data from the databases of the existing system of monitoring engineering structures is used to obtain the results. The tasks, set within the framework of the study, are accomplished by applying the theoretical methods of scientific knowledge: the analytical method, the mathematical statistics theory, induction. Results: the resulting structural approach to assessing the performance of the monitoring system for engineering structures on cable-stayed bridges makes it possible to reduce the number of false alarms of the system and assess the current state of the bridge structure. Within the framework of the III stage of the structural approach, it is proposed to develop a methodology for assessing the performance of the monitoring system for engineering structures with subsequent assessment of the current state of cable-stayed bridge structures. Practical significance: the results of the work are important for construction as they expand the understanding of the features of the mechanism of soil freezing.

I-SUM: Integrated Smart Ultrasonic Monitoring

iSUM (Integrated Smart Ultrasonic Monitoring) System is an integrated embedded ultrasonic guided-waves-based system consisting of methodologies and algorithms performed over data obtained by iSUM_ES devices to obtain damage detection, positioning, and characterization . i_SUM_ES device ruled by ISUM_SW performs tests and transmits the collected data to the controller device where it is processed . Through algorithms and AI models developed “ad-hoc” for each field of application, iSUM_APP provides clear, concise, and easily interpretable information of the current state of structures. iSUM System allows structural integrity inspection tests to be carried out by a minimally trained operator. It can also run scheduled tests autonomously and deliver alerts, reports, data raw on-demand or in the case of structural damage detection . This system aims to provide useful information about the most typical damages on engineering structures, reducing the time of inspection, and avoiding systems of complex installation and operation. Moreover, their use is intended to reduce inspection costs during manufacturing and operation, increasing the quality, safety, and durability of the systems composed of the target structures. This paper presents the industry needs that motivate this development, the system architecture, and the applications for which it has been conceived.

Experimental vibration-based output-only damage localization of mechanical systems

Vibration-based Structural Health Monitoring (SHM) is becoming increasingly widespread in a variety of engineering sectors as its variability enables diverse applications. It enables full-time assessment of the status of a structure, allowing for early maintenance and repair to prevent further damage or even failure. The presented study is part of the SPP100+ program, which has the objective of extending the usability of complex structures. This study presents an experimental investigation of the damage localization of mechanical structures while considering varying environmental and operational conditions (EOC). For this, a testing field was designed and applied, enabling one to study the effects of the varying conditions in a comparable way. The research is based on the approach to modify the state projection estimation error (SP2E) method to account for the influence of EOC. The proposed method utilizes output-only system identification and state space parameterization to estimate the current structural state. Stochastic subspace identification (SSI) and H_∞ -estimation are employed to identify the state space model during a learning phase. Subsequently, the SP2E method is applied during the monitoring phase to localize structural alterations. Moreover, an algorithm is introduced to estimate the weighting factors of different environmental and operational conditions. To verify the efficacy of the proposed method, an extensive experimental study is conducted. The numerical analysis successfully demonstrates the applicability of the method for localizing mass perturbation and stiffness degradation under various EOC. This work contributes to proactive maintenance and damage detection for mechanical structures under varying conditions.

A Physics-Data Hybrid Framework to Develop Bridge Digital Twin Model in Structural Health Monitoring

Digital twin aims to create a virtual model for a physical structure by combining measurement data in structural health monitoring. The most important feature is to achieve the physical structure-monitoring data synchronization. For this purpose, a physics-data hybrid framework to develop the bridge digital twin model in structural health monitoring is proposed in the paper. The physical base is firstly formed by the finite element model of the digital representation for the physical bridge that can fully incorporate both structural geometry and structural state. The data base is then built by all measurement data of the monitored bridge. By defining the context that is common to both physical base and data base, the mirror relationship between physical base and data base for the specified context is formulated. To achieve the best matching of the mirror relationship by minimizing process, the digital twin model in terms of the specified context can be developed. In such a way, the proposed framework integrates physical knowledge and data intelligence into one model. A demonstration of a simulated simply supported beam is provided to show how the digital twin model is developed by using proposed physics-data hybrid framework. It is found that the generated digital twin model is consistent with the current structural state of the beam. The presented physics-data hybrid framework helps in clearer understanding of the realization of digital twin model in structural health monitoring, providing a new perspective for smart bridge solutions.

STUDY OF THE INFLUENCE OF THE DYNAMICS OF THE DEVELOPMENT OF EMERGENCY DESTRUCTIONS ON ORGANIZATIONAL AND TECHNOLOGICAL SOLUTIONS FOR THE ELIMINATION OF THEIR CONSEQUENCES

Problem. Accidental destruction of construction objects occurs due to sudden external and internal influences of manmade and natural origin. Domestic gas explosions are the most common among emergency situations that lead to accidental destruction of residential buildings. Among the objects damaged by the explosion of the gasair mixture, a significant share is occupied by largepanel buildings. To develop measures for temporary strengthening and longterm strengthening of emergency structures and parts of the building, it is necessary to have operational information about the dynamics of their deformation state. Modern monitoring methods make it possible to obtain timely, objective information about the dynamics of the development of deformation processes of complex construction objects at all stages of their life cycle. Method. To substantiate the relevance of research, methods of analysis and generalization were applied, empirical research methods were used — instrumental monitoring, generalization of experience, expert surveys, expert assessments, scientific forecasting. On the example of a building that suffered significant damage as a result of an explosion of a gasair mixture, a selection of the optimal and safe method of its partial dismantling was made. Originality. Research using instrumental methods of the dynamics of deformations of the emergency object allowed to determine the optimal variant of the organization of dismantling and restoration works, taking into account the information received by the instrumental monitoring system. Increasing the efficiency and safety of works to eliminate the consequences of accidental destruction of largepanel buildings by choosing the optimal option for organizing emergency measures using modern information monitoring systems is an urgent technical and economic problem. The practical value lies in improving the organization of the dismantling of emergency buildings in conditions of incomplete information about their technical condition. The safety efficiency of emergency and rescue operations has been increased. A minimally justified composition of emergency measures with the use of a monitoring system to obtain information about the current state of structures for the purpose of implementing emergency measures is the most effective option for organizing emergency rescue and dismantling works in the process of restoring an emergency facility damaged by a manmade explosion.

Современное состояние и условия функционирования Усть-Манычских рыбоходных каналов

Purpose: to assess the state and operating conditions of the fish passage channels of the Ust-Manych waterworks on the river Western Manych. Materials and methods. The factual basis for assessing the state and operating conditions of the Ust-Manych fish passage channels was the materials of the author’s survey and field studies performed at the given facility in 2022. The studies were carried out according to generally accepted methods for conducting hydrometric measurements of flow rate parameters and geometric dimensions of channels and network (“canal”) hydraulic structures. Results and discussion. The survey data of structures and elements of two fish passage and spawning channels operating as part of the Ust-Manych waterworks, designated for passing semi-anadromous fish from its tail race to the head race - from the mouth of the river Western Manych to the Ust-Manych flood plain which is a potentially highly productive spawning ground for phytophils (bream, pike perch, carp and ram). The channel hydrometric parameters are given, a description of the structures included in their composition, ensuring the functioning of structures and structural elements or influencing it is given. The characteristics of the water flow on the structures and along the canal tract, as well as on the site of the conjugation of the canal mouth with the river are given. Estimated qualitative and quantitative indicators of the conditions for fish channel functioning are given. Conclusions. The survey data of the current state of structures and structural elements of two fish passage channels arranged around the Ust-Manych waterworks retaining structures were obtained. The hydrometric (flow-rate and geometric) channel parameters are given, and an assessment of the quality of their operating conditions on spawning-migratory fish passage from the river Western Manych to the spawning grounds located in the channel basin of the Ust-Manych waterworks is made.

Damage identification using wave damage interaction coefficients predicted by deep neural networks

The ever-increasing demand for efficiency and cost improvements in lightweight structures with guaranteed safety and reliability is leading to the application of a damage-tolerant design philosophy. Here, accurate knowledge of structural health is critical to avoid catastrophic failures. This knowledge can be obtained by using advanced structural health monitoring (SHM) systems. For thin-walled lightweight structures, methods utilizing guided waves generated by piezoelectric transducers are well suited. The interaction between the guided waves and potential damages can be described by so-called wave damage interaction coefficients (WDICs). These WDICs are unique for each damage and depend solely on its characteristics for a given structure. Therefore, the comparison of known WDICs with estimated ones allows drawing conclusions about the current structural state. In this paper, a novel damage identification method for plate-like structures based on a database of such WDICs is presented. Selected damages are simulated numerically with finite elements to generate WDIC patterns. However, these simulations are computationally highly demanding, thus only a very limited number of damage scenarios can be simulated. This study proposes an innovative technique to substantially enhance the resulting WDIC database by using deep neural networks (DNNs). These DNNs enable smart interpolations and allow not only predicting WDICs for previously unseen damages at low computational costs but also the discovery of knowledge about the complex relationship between damage features and WDIC patterns. A comparison to other machine learning algorithms clearly shows the superior performance of the utilized DNNs for interpolating complex WDIC patterns. The proposed damage identification method is verified using advanced time-domain simulations of a large aluminum plate. A statistical analysis of correct identification rates in a common three-sensor setting is employed for assessing the general performance. It is demonstrated that carefully identified DNNs enable to accurately replicate and interpolate complex WDIC patterns. Furthermore, it is shown that these predicted WDICs allow identifying damage characteristics with high confidence.

Energy balance and acoustic emission in titanium Grade 2 under fatigue

This work is devoted to the study of fatigue crack propagation features in titanium Grade 2 in order to develop effective methods for fatigue crack detection and prediction of its propagation rate. Two characteristic stages of heat dissipation are identified during fatigue crack growth. Also the stored energy during fatigue crack propagation is calculated by experimental data of mechanical work and heat dissipation. The stored energy rate is smoother than heat dissipation rate and it slows down when approaching the moment of damage. Cluster analysis of the signal allows us to identify two most probable clusters. The correlation between the acoustic emission energy and heat dissipation was found to be a harbinger of the approaching transition from stable to unstable crack growth. The relation between fatigue crack growth rate and the processes of energy dissipation and acoustic emission can be used in development of intelligent monitoring systems for assessment of current state of structure.

Damage localization of mechanical structures considering environmental and operational conditions based on output-only system identification and [formula omitted]-estimation

In this study the formerly introduced damage localization method state projection estimation error (SP2E) is modified to take varying environmental and operational conditions (EOC) into account. The method is based on output-only system identification and state space parameterization. This contribution introduces the basic concept of the novel method. This method is divided in a learning and a monitoring phase, the current structural state is subsequently identified by a state space model using stochastic subspace identification (SSI) and H∞-estimation. During monitoring phase method SP2E is then applied to localize structural alterations. Finally, to verify the proposed method, a numerical study is conducted. Localizing mass perturbation and stiffness degradation, the applicability of the proposed method has been proven in the context of EOC.

A review on Snake-like Continuum Robots for Medical Surgeries

This paper describes the various applications of Continuum robots in the field of medical science. These robots are biologically inspired by trunks and snakes. They possess the ability to transverse into small and restricted spaces, to manipulate objects in difficult environments and move in curved path. Due to this ability they can be extensively used in medical science as precision is very important in this field. Recently, increasing efforts have been made towards different surgical areas. In this paper recent state if structure, modeling and actuation in snake like robot is provided. Recently, increasing efforts have been made in various surgical interventions. In this paper, current state of structure, modelling and actuation in snake like robot is provided.

DEVELOPMENT OF NEW CONCRETE SPAN STRUCTURES FOR SMALL AND MEDIUM RAILWAY BRIDGES

Purpose. Improving of construction of reinforced concrete span structures for small and medium railway bridges. Methodology. To achieve the aim, modern designs have been considered and international experience of designing of reinforced concrete span structures has been analyzed. Findings. The research of actual normative documents, the current state of structures and technologies in the field of construction and major repair of small and medium span structures has been carried out. The improved construction of reinforced concrete span structures, which avoids the main problems that appear during the operation in structures of the existing construction has been developed. Originality. The new concept of external reinforcement of concrete span structures has been proposed. Reinforcement and formwork drawings of reinforced concrete span structures of railway bridges has been improved. Practical value. The proposed solutions allow to solve a number of problems that related to the production and exploitation of reinforced concrete span structures of railway bridges.

Application of Acoustic Emission Method and Impact Echo Method to Structural Rehabilitation

The paper is concerned with the technical aspects of the appraisal and retrofitting process of fire damaged reinforced concrete structures. The assessment of fire damaged structures is carried out along lines similar to those of the appraisal of existing structures. In practice, constructions are most often assessed by destructive tests in-situ and on core bore specimens. In addition to destructive tests, damaged structures are also assessed by non-destructive ones. The present paper shows the use of non-destructive methods of measurement using the acoustic-emission and impact-echo methods. Acoustic emission provides valuable data on the structural integrity of a material. This method has a significant potential to be used for in-situ monitoring and evaluation of the current state of structures. An impact-echo method is based on impact-generated stress waves that propagate through concrete and are reflected by internal flaws and external surfaces. Impact-echo can be used to determine the location and extent of flaws such as crack delamination, voids, honeycombing and deboning in plain, reinforced, and post-tensioned concrete structures. The paper presents a possible rehabilitation plan based on the potential results obtained by these non-destructive methods.

Evaluation of Restoration Project and Current Structural State of Mohamed Ali Mosque in Citadel, Cairo

Abstract This paper is aimed at achieving a better understanding of the original state before the restoration project in 1931 and the current structural state of the great Mosque of Mohamed Ali in citadel Cairo, Egypt. A 3-D finite element model for the whole Mosque was constructed for these purposes. Elastic analysis under static and lateral earthquake loads was conducted to verify the efficiency of the main covering domes restoration project in 1931 and to specify the positions of the critical stresses. The accurate and detailed information that was collected during the restoration project in 1931 concerning the structure of the Mosque was used as database for identifying the geometrical and structural properties of the model. The results provide insight to the structural behavior of the Mosque and the current state of stresses. The study also verifies the main causes for the valuable restoration project in 1931, where the stone domes and semi-domes covering the Mosque were replaced by reinforced concrete one . Also, the places of the Mosque that need more sophisticated analysis could be identified.

Tracking modal parameters from building seismic response data using recursive subspace identification algorithm

SummaryTracking modal parameters and estimating the current structural state of a building from seismic response measurements, particularly during strong earthquake excitations, can provide useful information for building safety assessment and the adaptive control of a structure. Therefore, online or recursive identification techniques need to be developed and implemented for building seismic response monitoring. This paper develops and examines different methods to track modal parameters from building seismic response data. The methods include recursive data‐driven subspace identification (RSI‐DATA) using Givens rotation algorithm, and RSI‐DATA using Bona fide algorithm. The question on how well the results of RSI‐DATA reflect the real condition is investigated and verified with a bilinear SDOF simulation study. Time‐varying modal parameters of a four‐story reinforced concrete school building are identified based on a series of earthquake excitations, including several seismic events, large and small. Discussions on the different methods' ability to track the time‐varying modal parameters are presented. The variation of the identified building modal frequencies and damping ratios from a series of event‐by‐event seismic responses, particularly before and after retrofitting of the building is also discussed. Copyright © 2017 John Wiley & Sons, Ltd.

Damage assessment and analysis of steel plate for different loading conditions

Damage is an undesired physical change formed in the structure that adversely affects its current or future performance. Damage is determined by comparing the current state of structure with its expected service state at that particular period. The process of detecting the damages and analysing its adverse effects on a structure becomes very crucial from the safety aspects. Thus Detection of damage in its early stage is essential. Hence structural health monitoring plays a major role in the field of damage assessment and rehabilitation of structures. The present study is intended on the analysis of damage of steel gusset plate in truss using MATlab software. The concept of Finite Element Method has been used to analyse the damaged plate. Two types of damages are considered in the present study i.e. damage due to corrosion and damage due to crack in a plate.

Overview: Methods of Crack Damage Detection Based on Modal Analysis

Introduced the history of development of crack damage detection technology and summarized the current state of damage detection technique based on modal analysis. Finite element method is the main method for mechanical structure modal analysis at present. Many researchers studied a single crack or multiple cracks impact on different structure’s dynamic characteristics, however, these studies only limited to the current state of structures with damage. Considering damage extending when mechanical structure being on work, a new method combines modal analysis and theory of damage extend is proposed to analysis the extending trend of damage, which make it easy to assess remaining life of mechanical structures and make structures that meeting design life can still being on work before they lose their effectiveness, this can save lots of costs

PZT Network and Phased Array Lamb Wave Based SHM Systems

With the application of newer materials, such as composite materials, and growing complexity and capacity of current aircraft structures, reliably and completely assess the condition of the total structures in real time is then of growing and utmost importance. PZT Network and Phased Array, Lamb wave based Structural Health Monitoring (SHM) systems were developed to be applied to thin panels. The selection of transducers, their size and selected locations for their installation are described. The development and selection of the signal generation and data acquisition systems is also presented in detail. The requirements conducing to the development and selection of these systems are laid and particularly the selection of the actuation signal applied is justified. The development of a damage detection algorithm based in the comparison of the current structural state to a reference state is described, to detect damage reflected Lamb waves. Such method was implemented in software and integrated in the SHM system developed. Subsequently the detection algorithm, based in discrete signals correlation, was further improved by incorporating statistical methods. For phased arrays, a novel damage location algorithm is presented based on the individual sensors response. A visualization method based concurrently in the statistical methods developed and superposition of the different results obtained from a test set was implemented. These tests conducted to the successful and repeatable detection of 1mm damages in a multiple damaged plate with great confidence. Finally, a brief comparison and a hybrid system implementation is presented.

Numerical characterization of the structural behaviour of the Basilica of Pilar in Zaragoza (Spain). Part 1: Global and local models

The Basilica of Pilar, located in the city of Zaragoza, is one of the most famous Spanish temples. Several domes of this church contain frescoes painted by Francisco de Goya, which have suffered damages in the past decades due to various pathologies. The frescoes of the Regina Martirum dome are being restored at the present time. In this paper, we present a set of structural models of the entire temple and local models of the Regina Martirum dome by discussing and comparing the obtained results. The main objective of the research was to identify the current structural state of the church, its safety level and the relationship between the structural behaviour and the damages observed. The behaviour of the main material used in the construction, brick masonry, was simulated first with linear elastic isotropic models and later with several non-linear isotropic models including brittle behaviour in tension and plastic behaviour in compression. In addition, we consider the historical construction and the reinforcement works added to the structure in its history, with the purpose of testing the finite element models by reproducing the pathologies described from the beginning of the current Baroque construction.

The 2004–2005 Etna eruption: Implications for flank deformation and structural behaviour of the volcano

The development of the 2004–2005 eruption at Etna (Italy) is investigated by means of field surveys to define the current structural state of the volcano. In 2004–2005, a fracture swarm, associated with three effusive vents, propagated downslope from the SE summit crater towards the SE. Such a scenario is commonly observed at Etna, as a pressure increase within the central conduits induces the lateral propagation of most of the dikes downslope. Nevertheless, some unusual features of this eruption (slower propagation of fractures, lack of explosive activity and seismicity, oblique shear along the fractures) suggest a more complex triggering mechanism. A detailed review of the recent activity at Etna enables us to better define this possible mechanism. In fact, the NW–SE-trending fractures formed in 2004–2005 constitute the southeastern continuation of a N–S-trending fracture system which started to develop in early 1998 to the east of the summit craters. The overall 1998–2005 deformation pattern therefore forms an arcuate feature, whose geometry and kinematics are consistent with the head of a shallow flank deformation on the E summit of Etna. Similar deformation patterns have also been observed in analogue models of deforming volcanic cones. In this framework, the 2004–2005 eruption was possibly induced by a dike resulting from the intersection of this incipient fracture system with the SE Crater. A significant acceleration of this flank deformation may be induced by any magmatic involvement. The central conduit of the volcano is presently open, constantly buffering any increase in magmatic pressure and any hazardous consequence can be expected to be limited. A more hazardous scenario may be considered with a partial or total closing of the central conduit. In this case, magmatic overpressure within the central conduit may enhance the collapse of the upper eastern flank, triggering an explosive eruption associated with a landslide reaching the eastern lower slope of the volcano.