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Development and application of wavelet-based algorithms for damage localization in two-dimensional structures

Journal of Building Pathology and Rehabilitation 2025年第1期10卷 1-16页

作者： de Sá, Rafael Alan Gomes, Gilberto Silva, Ramon Graduate Program in Structures and Civil Construction - PECC University of Brasília Brasilia Brazil

Damage detection in civil engineering is crucial for ensuring the safety and maintenance of infrastructure. This study introduces the development and implementation of innovative algorithms based on the Wavelet Transform (WT) for damage detection and localization in two-dimensional structures, integrated with the Boundary Element Method (BEM). The study conducts a detailed multiresolution analysis of displacement data using an academic computational package for modeling, meshing, and data acquisition. Key analyses include evaluating the effectiveness of different wavelet families in damage detection, assessing the impact of varying the Reference Line (RL) resolution from 19 to 9 points, and examining the trade-offs between computational efficiency and accuracy. The algorithms are validated on two beam typologies: fixed-free (cantilever) and fixed–fixed (double-clamped). The results demonstrate high accuracy in damage localization. The findings highlight the advantages of combining WT with BEM for structural monitoring, offering significant improvements over traditional methods. The paper concludes by discussing the potential for applying these techniques to a broader range of structures and damage scenarios, aiming to enhance the reliability and scope of structural health monitoring systems. © The Author(s), under exclusive licence to Springer Nature Switzerland AG 2025.

关键词： BEM Interactive algorithms Multiresolution analysis Structural damage detection Wavelet transform

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Determination of time zero in high strength concrete containing superabsorbent polymer and nano-silica

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Journal of Building Pathology and Rehabilitation 2016年第1期1卷 1-12页

作者： Cunha, T.A. Francinete, P. Manzano, M.A. Aidar, L.A. Borges, J.G. Silva, E.F. Post-Graduate Program in Structures and Civil Construction (PECC/UnB) University of Brasília Brasília Federal District Brazil Civil Engineering Department (ENC/UnB) University of Brasília Brasília Federal District Brazil

The autogenous shrinkage is a phenomenon that occurs due to the appearance of tensile stresses in capillary pores. Inherent in the hydration process, not depending on external interference. In high strength concrete, autogenous shrinkage is most pronounced, due to the refinement of microstructure, the high cement content, presence of mineral addictions and low water/cement ratio, which interfere in the transport of water curing. In this context, Superabsorbent polymers (SAP) stand out for their ability to reduce or eliminate the autogenous shrinkage, because they absorb large amounts of water, which is subsequently released into the matrix, avoiding self-desiccation and the onset of tensile stresses (internal curing). However, studies show that SAP can reduce the mechanical strength, which can be compensated by addiction of Nano-silica (NS). In this paper, the effect of these additions in Time Zero (T₀) was evaluated. T₀ determines the time at which the material starts to behave as a solid, with the development of a rigid mineral skeleton to oppose the volumetric variations that occurs in the paste, which can lead to cracking, compromising esthetics, durability, and structures safety. The ultrasonic pulse velocity test performed the T₀, which measures the velocity of propagation of an ultrasonic wave through the material and is taken as the time when a sudden change occurs at this velocity. Nine blends were made containing SAP and NS, where it was found that SAP addition increases the T₀ (up to 11%), while NS decrease its value (in 55%). © 2016, Springer International Publishing Switzerland.

关键词： High performance concrete High strength concrete Nano-silica Superabsorbent polymer Time zero Ultrasonic pulse velocity

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Application of the principles of lean thinking in the post work construction department

Application of the principles of lean thinking in the post w...

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20th Conference of the International Group for Lean construction, IGLC 2012

作者： Cupertino, Daniel Vilarinho, Sammea A. Alencar, Leonardo Do Amaral, Tatiana G. Graduate Program in Geotechnic Civil Construction and Structures School of Civil Engineering Federal University of Goiás Brazil Graduate Program in Building Technology and Management School of Civil Engineering Federal University of Goiás Brazil

The increase on the competitiveness, the search on the customer satisfaction, the search by reducing waste in civil construction were facts that helped entrepreneurs and companies to seek new ways of working, being lean construction one of the ways to get that. Studies report that the application of the Lean tools in construction was carried out in an isolated way. This type of application was pointed as a major fact limiting the extent of achievement in implementing Lean principles. The aim of this studies is to identify opportunities to implement the principles of Lean Production in the service department of a construction company in Goiás, proposing routines that try to implement the continuous improvement of its processes, eliminating waste, reducing the Lead Time, allowing it to perform the mapping processes, improving the way records of requests for technical assistance, among others. For data collection it was carried out a semi-structured interview in four construction companies. Through the analysis of the responses, some Lean tools were developed like flowchart mapping of activities, an action plan for preventive maintenance and an application form for technical assistance, focusing on helping small and medium construction building companies to structure a Post Work construction Department ruled on the Lean principles (pull, perfection, value stream). It was concluded pointing out some difficulties in the implementation of lean principles in the department and emphasizing the Lean concepts that can be presented within the activities of the Post Work construction Department.

关键词： Customer satisfaction

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Relative importance of pathologies in the severity of facade degradation

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Journal of Building Pathology and Rehabilitation 2020年第1期5卷 1-10页

作者： Bauer, Elton Piazzarollo, Carla Bozzi de Souza, Jéssica Siqueira dos Santos, Danilo Gonçalves Post-Graduate Program in Structures and Civil Construction Civil and Environmental Engineering Department University of Brasília Campus Universitário Darcy Ribeiro Asa Norte Brasília DF Brazil

The facade is the main protective barrier against the atmospheric agents acting in a building. Many times, as a result of these agents, the facade manifests pathologies that lead to the loss of performance of the external wall claddings. This article aims to establish and score the importance of the pathologies involved in the cement mortars rendering. The probable causes and the influence on the performance decrease over time are analyzed. The methodology is based on the survey and mapping of the pathologies observed in field survey, correlating these pathologies with probable causes and implications for the system performance. Among the active pathologies, cracks had both a higher intensity of occurrence and a greater gravity compared to the others. Some pathologies, such as detachment and efflorescence, although of great importance in the degradation, are little observed in the studied buildings. As a result, is presented a scale of importance of pathologies, which has great application for the development of facade degradation models. © 2020, Springer Nature Switzerland AG.

关键词： Cement mortar Degradation External wall claddings Facades Pathologies

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Study of a hybrid inverted pendulum tuned mass damper behavior using a PID control 11

Study of a hybrid inverted pendulum tuned mass damper behavi...

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11th International Conference on Structural Dynamics, EURODYN 2020

作者： Falcão, Jonas P. Moreno, Ledymar F. de Brito, José L.V. de Morais, Marcus V.G. Avila, Suzana M. Graduate Program in Structures and Civil Construction University of Brasilia Darcy Ribeiro Campus Asa Norte BrasíliaDF 70910-900 Brazil Graduate Program in Engineering Materials Integrity University of Brasilia Campus of Gama Gama DF72444-240 Brazil

ISBN: (纸本)9786188507210

Tuned mass dampers are devices well known in the literature. It is an auxiliary mass system that correctly tuned when connected to the structure vibrates out of phase with it, having the energy transferred to itself and thus reducing the vibration level of the main system. Among the geometries of this type of damper stands out the pendular one. However, recent studies show that inverted pendulum configuration would be more appropriate and efficient. The inverted pendulum problem itself is widely discussed in the literature, but its application as a structural control device acting as a tuned mass damper has not been sufficiently studied. The originally passive control device can be designed to operate in a hybrid manner with the addition of an active controller to the system. This configuration has the advantage of being more robust than passive, which only works well in the design frequency range, and requires lower control forces than purely active control. In this work a hybrid inverted pendulum mass damper (TMD-HIP) is proposed, where in addition to tuning it from the pendulum length and mass, an active control device is added. The active force used is designed as a PID controller with optimized gains. Numerical simulations are performed using the MATLAB computational package and its SIMULINK control toolbox. Several forms of external excitation are considered in the analysis. From the results it appears that the TMD-HIP is a good alternative for reducing excessive vibration. Although it is a preliminary model, it is a basis for studies in this area to evolve to more sophisticated model and full-scale applications. © 2020 European Association for Structural Dynamics. All rights reserved.

关键词： Inverted pendulum

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Influence of slenderness ratio in the modal analysis by analytical formulation 11

Influence of slenderness ratio in the modal analysis by anal...

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11th International Conference on Structural Dynamics, EURODYN 2020

作者： Falcão, Jonas P. Carvalho, Rodolfo A. Ribeiro, Renan R. Moreno, Ledymar F. de Brito, José L.V. Graduate Program in Structures and Civil Construction University of Brasilia Darcy Ribeiro Campus Asa Norte Brasília DF70910-900 Brazil Graduate Program in Engineering Materials Integrity University of Brasilia Campus of Gama Gama DF72444-240 Brazil

ISBN: (纸本)9786188507203

This paper presents a dynamic analysis of a single-storey frame composed by one beam and two columns in order to compare the modal analysis results of a full-continuous analytical formulation, based on the Euler-Bernoulli model, to different simplified discrete models. The four models analyzed, through Maplesoft 2015.1, are: shear frame model, concentrated mass model, and consistent mass model, which are discrete models, and a full-continuous analytical formulation based on the Euler-Bernoulli model. Historically, simple discrete models, such as the shear building model, have been used rather than continuous analytical formulations due to their simplicity and good accuracy in many practical situations. Nevertheless, geometric characteristics of current structures have changed and, consequently, their dynamic behaviour tends to depart from those ideal for many simplified discrete models. The results obtained illustrated the effect of the element’s slenderness and the model type on the first natural frequency obtained with the four different models. The slenderness of 50 represented a benchmark for result analysis, with the concentrated and consistent mass models presenting frequencies similar to the Euler-Bernoulli model when the column slenderness was higher than 50 and the beam slenderness was lesser than 50. Also, the analysis of the first mode shape suggested that this property is not highly influenced by the model type. © 2020 European Association for Structural Dynamics. All rights reserved.

关键词： Natural frequencies

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Facades inspection with infrared thermography: cracks evaluation

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Journal of Building Pathology and Rehabilitation 2016年第1期1卷 1-7页

作者： Elton Bauer Elier Pavón Elias Oliveira Claudio H. F. Pereira Post-Graduate Program in Structures and Civil Construction Civil and Environmental Engineering Department University of Brasília Brasília Brazil Centro das Ciências Exatas e das Tecnologias Post-Graduate Program in Structures and Civil Construction - UnB Universidade Federal do Oeste da Bahia-UnB Barreiras Brazil

Infrared thermography is an evaluation technique that helps to identify anomalies and can provide information on their incidence and severity. The aim of this study is to apply quantitative thermography to study a case of severe cracks in facade analyzing the evolution of temperatures and Delta-T. The temperature evolution was studied over a day. There was sun incidence occurring during part of the day, allowing to calculate and assess the evolution of the associated temperatures. Thermograms were acquired hourly during the study period. The highest temperatures were observed at 12:00 noon, and the larger Delta-T between 10:00 and 12:00. There were differences between the Delta-T profiles among the three regions studied. The best time for analysis is when Delta-T is higher. Cracks with higher Delta-T were considered more degraded, and generalized branched cracks did not allow a comparative conclusion.

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Properties of Concrete Produced with Recycled Concrete Aggregate Treated with Portland Cement, Metakaolin and Nanosilica

SSRN

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SSRN 2022年

作者： Nóbrega, Érica Capuzzo, Valdirene The Graduate Program in Structures and Civil Construction University of Brasilia Federal District Brasília70910-900 Brazil

This research presents the results of different methods of treating recycled concrete aggregates (RCA). The two-stage mixing approach (TSMA) was used to create five concrete mixes containing Portland cement (PC), metakaolin (MK), and nanosilica (NS). Two mixes were used as reference, with and without RCA, and three others containing RCA treated with PC, MK and NS. The percentage of RCA used was 20%. The fresh-state specific mass, compressive strength, tensile strength, elastic modulus, water absorption, chloride migration, and carbonation front were measured. The mechanical properties and durability tests results for the mix containing untreated RCA and RCA treated with PC were similar to the reference mix. The mixes containing MK and MK with NS performed significantly better than the reference mixes. Positive changes occur in the mechanical properties and durability of concretes containing RCA, particularly those containing MK and NS, demonstrating the feasibility of using RCA in structural concrete. © 2022, The Authors. All rights reserved.

关键词： Portland cement

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Wind-driven rain incidence parameters obtained by hygrothermal simulation

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Journal of Building Pathology and Rehabilitation 2016年第1期1卷 1-7页

作者： Nascimento, M.L.M. Bauer, E. de Souza, J.S. Zanoni, V.A.G. Post-Graduate Program in Structures and Civil Construction Civil and Environmental Engineering Department University of Brasília Campus Universitário Darcy Ribeiro Asa Norte Brasília 70910-900 DF Brazil Faculty of Architecture and Urbanism University of Brasília Campus Universitário Darcy Ribeiro Asa Norte Brasília 70910-900 DF Brazil

The association of rain and wind composes wind-driven rain (WDR), and its incidence may be crucial to the emergence of anomalies on the facades of buildings. Moisture from the WDR can influence the humidification and drying process, therefore the durability and hygrothermal performance are conditioned by the amount of incident water. The quantification of WDR can be an indispensable tool for understanding its related phenomena and the service life of buildings. The most widely used methods of quantification are the semi-empirical, with theoretical basis, but coefficients partially determined from measurements. These methods may take into account the building exposure conditions related to the envelope, solar orientation, height of the building, and other parameters. In this context, in order to contribute to the studies on quantification of WDR, the purpose of this paper is to apply hygrothermal simulation software WUFI^® on quantification of WDR focusing on buildings degradation of Brasília-Brazil. For the simulation it was used a Typical Meteorological Year file with the wind and precipitation measurement data indispensable for simulation. The quantification of incidence of WDR considered the orientations North, Northeast, East, Southeast, South, Southwest, West, and Northwest. The use of semi-empirical WUFI^® quantification method allowed finding the highest values and consequently critical orientations North, Northwest, and Northeast, moreover, this results showed the relation with the degradation of facades in these orientations. WUFI proved to be an easy, fast and efficient method of WDR quantification, without hiding seasonal weather effects. © 2016, Springer International Publishing Switzerland.

关键词： Degradation Facade Hygrothermal simulation Wind-driven rain

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Study of damage distribution and intensity in regions of the facade

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Journal of Building Pathology and Rehabilitation 2016年第1期1卷 1-9页

作者： de Souza, Jessica S. Bauer, Elton Nascimento, Matheus L. M. Capuzzo, Valdirene M. S. Zanoni, Vanda A. G. Post-Graduate Program in Structures and Civil Construction Civil and Environmental Engineering Department University of Brasília Campus Universitário Darcy Ribeiro Asa Norte Brasília 70910-900 DF Brazil Faculty of Architecture and Urbanism University of Brasília Campus Universitário Darcy Ribeiro Asa Norte Brasília 70910-900 DF Brazil

The ceramic coating systems applied to building facades have relevant aesthetic value and protection functions. The architectural and environmental conditions can greatly influence the degradation process of the facades, which may pose risks and compromise the durability and service life of the building and its components. The degradation process of facades changes according to the region where it takes place. To this end, the present study aims to determine damage intensity and distribution in the different regions of the facade. This study investigated the facades of three buildings that are part of the Materials Testing Laboratory (LEM) database of the Universidade de Brasilia. The degradation was quantified using a methodology proposed by Silva (2014) to generate a degradation index expressed in m². After the quantification of damages, few indexes associated with the percentage of degraded area, applied to the facade regions, are presented. These weighted indexes allowed to standardize the values observed in each region. Obtaining these indices is fundamental to the study of degradation. The results show that for a comparative analysis between the regions, the observed values should be corrected for the proportionality of the area of each region in relation to the total area of the facade. It was also noted that the continuous walls are the most affected regions, but they do not always present the highest damage intensity. © 2016, Springer International Publishing Switzerland.

关键词： Damage distribution Degradation Degradation index Facades Pathology

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