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Optical fiber sensors have great potential for application in civil construction, especially in the field of structural health monitoring. However, one of the barriers to the diffusion of these sensors is allied to the fact that their implementation is quite expensive, mainly due to the high price of commercial optical interrogators. Therefore, the present work seeks to develop a low-cost optical interrogation system. For this, the present study proposes the development of this system based on the use of tunable filters and edge filters in the monitoring of low and high frequencies, and consequent digital processing of the collected signals through the find_picks algorithm and the Fourier transform. As a result, it was possible to observe the adequate functioning of the tunable filters, with the validation of the system using a FBG, and a previous simulation for the edge filter system with frequencies superior to 100 kHz.

The data acquisition process is an important step in capturing information, especially when it comes to historical heritage documentation, these buildings often have complex structures and little collection, which makes the geometric survey process by the traditional way even more difficult. Currently studies have been conducted using 3D terrestrial laser scanner (TLS) as a capture of geometric information in order to generate point clouds and serve as a basis for analysis, including using BIM and facilitate this documentation process. The paper was developed from a theoretical basis on the subject and application, performing a metric evaluation comparing existing point cloud and 2D surveys, in order to generate a database and propose a method to improve dimensional inspections through point clouds in historic buildings, where it was possible to note some differences in shape and measurement between the two surveys. The study was validated on the metal façade of the José de Alencar Theater.

The objective was to evaluate the influence of Baosteel slag short flow (BSSF) steel slag, a byproduct of a Brazilian steel mill, as a fine aggregate on the properties of fresh state and on the compressive strength of mortars. The experimental work was to characterize the BSSF steel slag and to produce simple mortars (only cement) and mixed mortars (cement and lime), replacing the natural sand with the slag aggregate in 20%, 40%, and 60% by volume. The fresh state tests were specific mass, incorporated air, water retention, and squeeze-flow, while in the hardened state, compressive strength at 28 days was investigated. It was verified that mortars with higher slag contents required greater amounts of water to obtain the spread (consistency) on the flow table, which was fixed at 260±5 mm. The mortars with slag presented higher specific mass since the slag had a higher density than natural sand and less water retention in the case of simple mortars. In addition, it was verified that the mortars with BSSF steel slag presented lower values of maximum displacement in the squeeze-flow test, which negatively affected its workability in the fresh state, besides the properties of mortar adherence. In addition, it was verified through the analysis of variance that the substitution of natural sand by BBSF steel slag did not significantly influence the compression strength of mortars.

Purpose The study aims to identify and evaluate relevant criteria in the proposal and support of public administration policies for preventive maintenance comprised in a conservation approach to built heritage and aligned with local sustainable development of the historic center of the city of Sobral, in Brazil. Design/methodology/approach A novel multicriteria decision model adopting the Bayesian best-worst method is presented and its application and results are described. Though a systematic procedure, criteria were selected in order to protect the tangible and intangible values of cultural heritage, as well as its sustainable development. Then experts evaluate these criteria through an elicitation instrument. Findings The results show that for the decision problem over preventive maintenance, social contribution and historical record of built heritage are more important than its structural vulnerability, while architecture is less relevant. Due to the low restrictions, the subcriterion related to this property has the least influence. The weights can assist in the characterization of measures and policies for the protection of the built cultural heritage. Originality/value The use of a novel decision-making method in cultural heritage is an important initiative, given the frequent use of simple and inefficient methods. The identified and weighted criteria are important data to characterize the scenario and the topic. The results contribute to protection and development of the built heritage, encouraging the implementation of preventive conservation in the historic center, conferring to the public administration valuable information to support and propose initiatives.

This work has as the main aim proposes a novel approach for the detection of voids in ancient masonries based on ultrasonic data collected by indirect measurements. For that, two samples of ancient walls were built and tested in the laboratory. The first wall sample was built with anomalies (voids) distributed along its area, while the second one was built without voids. The wall samples were divided into 12 frames. In each frame 6 time-measures of ultrasonic propagation were performed. The results showed that the ultrasonic data collected by indirect measurements can be used to characterize masonries. Also, the results show that the assembly between Mixed effect and Lowess models for processing ultrasonic data, can be a powerful tool to detect and identify the voids inside the masonries walls, even in anisotropic materials like masonries, if the distribution of the waves and its behavior is understood, it is possible to identify disturbs on the data by anomalies presence, as voids. This work also demonstrates that, for analysis of anisotropic materials, the pattern distribution of ultrasonic waves can be an alternative way to characterize masonries.

In this work ultrasonic pulse velocity (UPV) was used to assess the coating mortar adherence of clay bricks masonries. As a contribution to employment of non-destructive tests to historic buildings characterization, this paper has as the main aim to introduces a new methodology for damage identification (especially the presence of cracks) and coating mortar detachments in masonry walls. For that, an experimental setup based on ultrasonic measurements were carried out on the external walls of the Nossa Senhora da Expectacao Church, built in 1709, at Ico, Brazil. The results showed that ultrasonic pulse velocity mapping can be used to identify the adherence and the non-adherence between coating mortar and the masonry. Also, a standard pattern of ultrasonic velocity distribution for masonry was identified. Finally, in this paper a new point of view on UPV interpretation was introduced, namely based on analysis the pattern of waves distribution.

Destructive and non-destructive tests were performed to characterize clay bricks from 18th to 20th century from vernacular historic constructions placed at Ceara State, Brazil. The present work has as the main aim to characterize the physical and mechanical properties of Brazilian historical clay bricks, namely water absorption index, ultrasonic pulse velocity and compressive strength. In general, cases of ancient materials characterization out of Europe zone are rarely reported at the literature. For that, samples from vernacular constructions placed at different regions of the Ceara State were tested. The results point to similarities between the clay bricks analyzed, and an evolution in the quality of the properties analyzed. Additionally, the results of the present paper are good contributions to development of numerical models and as well to the understanding about the loading capacity of historic Brazilian masonries. Also, the results allowed to state a correlation between physical and mechanical characteristics of the Brazilian clay bricks based on ultrasonic pulse velocity and the periods of the bricks manufacturing.

Corrosion is a relevant mechanism of the material decaying. The emergence of cathodes and anodes zones are influenced by electrons transfers. If the cathodes and anodes emerge in different locations of a structure, it can contribute to a generalized corrosion process in an area. Thus, the analyses of the corrosion by punctual measures can be not an assertive way to characterize the extension of the damage. Aggressive agents can accelerate the corrosion evolution, as chlorides and sulphates, for instance. The present work has as the main aim analyses how the corrosion potential mapping can be used to characterize the corrosion evolution over the time in a real structure. For that an electrode with copper sulphate was used to collect the values of corrosion potential in a steel frame structure, placed at Fortaleza, Ceara, Brazil. Measurements were performed through 81 points distributed along the structure, distant 20 cm each other. The values of corrosion potential were monitored for 99 days. The results showed that the non-destructive monitoring of corrosion potential can be a very efficient way to assess the evolution and to quantify the corrosion in a panel over the time.

Structural collapse of civil engineering structures at an early age, as for instance bridges, tunnels and buildings, can present a high impact on economic issues of cities around the world, which emerges the necessity of early corrective maintenance and deep interventions. In this context, recent years, new studies and strategies focused on the durability of reinforced concrete structures have been developed. This case study aims to estimate the residual service life of a newly constructed reinforced concrete structure based on in-situ measurements of concrete cover, performed in 1662 points of columns and slabs to assess the impact of possible divergences between designed and as-built structural elements. Results show that a combination of concrete cover lower than the minimal and water/cement ratio higher than the maximum specified by Brazilian standards resulted in service life under 50 years in 53.8% of the inspected points of columns and 100% of the inspected points of waffle slabs. Even inspected points with concrete cover higher than the minimum requirement of the Brazilian design standard resulted in residual service life under 50 years. In critical points, the estimated residual service life resulted in 9.5 years for columns and 20 years for waffle slabs, which is far below the expected performance for a newly built reinforced concrete structure.

Heritage constructions (HC) presents cultural, historical and architectural remarks of a community. This way, maintenance and rehabilitation of HC is an effort each time necessary for keep these structures in safety and in good state of conservation for the future generations. The materials characterization can be a key for that. To characterize the materials of a HC can allow to collect information to support the decision on what conservation strategy to follow, as well give information on the constructive techniques employed and its originality. This work has as the main aim to investigate the physical and chemical characteristic of the mortars and clay bricks samples of the Nosso Senhor do Bonfim Church, placed at Aracati downtown, in the Ceara State, Northeast of Brazil. The church was built in XVIII century and the main facade presents the so-called as “barroco sertanejo”, an architectonic style influenced by Portuguese baroque. A Portuguese heritage from the Brazil colonial period. The results showed the existence of two different mortars layers covering the church walls, where in the most superficial layer cement presence was detected. Information on the original mortar composition was collect, as well clay bricks physical and mechanical properties. This information can be useful for materials and strategy selection in future interventions on the Nosso Senhor do Bonfim Church and contributes to fill the gap of information on luso-brazilian historic construction.

In this work, ultrasonic tests were carried out on the external walls of the Nossa Senhora do Rosario dos Pretos Church, an ancient masonry structure from XVIII century, placed at Aracati, Brazil. The main aim of this research is to characterize the ultrasonic velocities of the external walls of the church and identify the heterogeneity of the masonries; to assist furthers maintenance measures, as well to collect quantitative data about the state of conservation of the church. Ultrasonic results are, in general, difficult to analyze, especially due to the variability of the measures way. This way, a methodology to collecting the measures of indirect ultrasonic measurements was developed and it is presented in this paper. This methodology consists in a frame-by-frame comparative analysis of contour maps, obtained from systematic measures of ultrasonic pulse. The method allows the application of indirect ultrasonic measures to characterize clay bricks panels, as well allows the repeatability of further measures in the same points. The results show that ultrasonic tests can be applied for characterize walls homogeneity, offering useful information to control the maintenance or retrofitting measures.

Bond-slip is an important interaction between steel and concrete in reinforced concrete (RC) structures and other civil engineering constructions. It is essential to understand and to characterize, at local level, this stress transference mechanism. In particular its behavior for monotonic and cyclic demands, the parameters that influence this mechanism, and how it is affected by different deterioration factors. Therefore, characterizing and monitoring the bond-slip mechanism is essential for the safety assessment of RC structures, more specifically determining the reinforcing bars slippage inside the concrete, and therefore the stress and strain distribution in RC members. In this work, two optical fiber sensors are presented, based on silica and polymer fiber Bragg gratings (FBGs), which were implanted inside a concrete block specimen and subjected to a pull-out test. After 6 days of curing, the pull-out test was recorded and the displacement incurred during the test was also monitored with a traditional electric sensor; for comparison with the data acquired with the two optical sensors. The results obtained confirm the viability and advantages of the optical sensors, evidenced by their higher resolution and far lower dimensions (allowing them to be embedded into the concrete) when compared with their electronic counterparts. The straightforward implementation and use of the optical sensors show very promising results when used in civil engineering structures.

In this work, ultrasonic tests were carried out on the external walls of the Nossa Senhora do Rosario dos Pretos Church, an ancient masonry structure from the 18th century placed at Aracati, Brasil. The main aim of this research was to characterize the ultrasonic velocities of the external walls of the church, in view of further maintenance measures, as well to collect quantitative data on the state of conservation of the church. Fort that purpose, a methodology based on indirect ultrasonic measurements was developed and is presented in this paper. The results show that ultrasonic tests can be applied for characterizing wall homogeneity, offering useful information for control of maintenance or retrofitting measures.

Recent advances on sensing and data communication systems have allowed the optimization of the structural health monitoring systems, as well their employment for long-distance remote monitoring of civil structures. Moreover, structural health monitoring techniques can be particularly interesting for heritage constructions assessment, because they allow a real-time analysis of the structural properties, and the collected data can be used as support of safety maintenance. This work describes the strategies employed for structural health monitoring of a damaged historic structure from the XVI century, namely the Foz Coa Church (in Portugal), beside the results of 1-year monitoring of the displacements observed on the structural elements of the church. Additionally, the influence of the temperature and relative humidity were studied. Removing the environmental influences from the observed displacements in the structural elements allowed to conclude that these are not motived by the damage progression, instead they are related with influence of environmental parameters.

Heritage constructions presents high significance and importance for society. As way of contribution for the preservation of the heritage constructions, this paper presents a study on the dynamic behavior of a heritage construction, part of the historic center of Sobral city, located at the north region of Ceará State, namely the Nossa Senhora das Dores Church, a church from the beginning of the 19th century, built in clay brick walls. In this study, ambient vibration tests were performed aiming to obtainment of the natural frequencies of the building focusing the calibration of the numerical model and, from it, proceeding with modal analysis by Finite Element Method (FEM) with recurrence to software Ansys®. The results allowed the analysis of the structural dynamic behavior taking into account natural frequencies, modal shapes and directional displacements. Resumo As construções históricas possuem elevado significado e importância para a sociedade. Como contribuição à preservação do patrimônio histórico, o presente trabalho apresenta um estudo sobre o comportamento dinâmico de uma edificação histórica, inserida no âmbito do patrimônio histórico da cidade de Sobral, localizada na região norte do estado do Ceará, nomeadamente Igreja de Nossa Senhora das Dores, uma capela do início Século XIX, construída em alvenaria de tijolos maciços. Neste estudo foi realizado o ensaio de vibração ambiental com objetivo de obter as frequências naturais da edificação com foco à calibração do modelo numérico e, a partir dele, com recurso ao software Ansys®, realizar a caracterização modal via Método dos Elementos Finitos (MEF). Os resultados obtidos permitiram analisar o comportamento dinâmico da estrutura, no que se refere à obtenção das frequências naturais, modos de vibração e deslocamentos direcionais.

Water elevated reservoirs are commonly designed for drinking water storage in small communities. Usually they comprise prefabricated steel structures of elevated tanks, especially due to fast assembly of the component parts once parts of the structure just need to be connected. That one was the construction system used in small communities in the State of Tocantins, Brazil. However, weld joint failures have caused degradation and damage occurrence in the water elevated reservoir components welded by Shielded Metal Arc Welding (SMAW) process that uses a flux-coated electrode to form the weld. In this work, an investigation was carried out in order to analyze the existence of pathologies in the welded joints in the water elevated reservoir located in Tocantins. Following, the components were tested to tensile strength (NBR 6892-1: 2013) in plates equal to those used in water elevated reservoirs and with joints welded intentionally with the same identified pathology. The damages found by visual analysis were related to fast cooling, slag inclusions, high and low welding amperage and moist welding electrodes. Concerning the tensile strength test, joint welded with low welding amperage and joint welded with moist welding electrodes presented more damages, results that evidenced the importance of the quality control of the weld in this construction system.

Some features as workability, high durability and low cost of production have contributed for reinforced concrete (RC) be largely used worldwide. However, environmental actions and the natural material decaying are the most common processes that contribute for the loss of the physical-mechanical properties of the RC structures. When the bond between the concrete and the reinforcing rebar are affected, the results can be extremely dramatic and unpredicted. In this work, an optical fiber device for the monitoring of the bond-slip of old RC structures, where less intrusive techniques need to be considered, is proposed and tested. The sensor developed is based on the fiber Bragg grating (FBG) technology, inscribed in silica optical fiber. A pull-out test was carried out in a RC specimen, following the recommendations of the Annex D of the EN 10080. The results showed that the bond-slip optical sensors are capable to measure micro-displacements, with lower intrusiveness. Therefore, they can be used for monitoring the bond-slip of old RC structures as way of to collect information, essential to assist the owners to adopt cost effective, efficient and safer maintenance measures.

The Ceara State, northeast of Brazil, has an acknowledged stock of heritage buildings located in the cities of Aracati, Sobral, Ico and Vicosa do Ceara. These Luso-Brazilian historical buildings are masonry structures dating from the 18th, 19th and 20th centuries and are important historical cultural assets. This way, the present paper has as the main aim to assess the structural vulnerability of facades of Ceara heritage constructions, namely the historic cities of Aracati and Sobral. This paper lists the recurrent and major damages of building facades and spatially maps the structural vulnerability results. For this purpose, a novel structural vulnerability assessment of the facades, focused on typical historical Brazilian masonries is presented. The procedure is based on the assessment of qualitative and quantitative parameters derived from the analysis and treatment of general information on the structure, such as geometrical characteristics, construction technology and material properties. The results show that information on the structural vulnerability of heritage buildings can be a relevant tool to support the design intervention plans as well to identify the critical situations in need of urgent conservation/retrofitting. This paper is a precursor to dynamic analysis in Brazilian historical centers.