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Corrosion of carbon steel reinforcement is the major cause of premature deterioration of reinforced concrete infrastructures. There is increasing interest in the use of maintenance-free materials such as stainless steel reinforcement in concrete, with inherent durability and resistance to various forms of corrosion and favourable mechanical properties, in particular high ductility and substantial strain hardening. This paper presents the results of the first large-scale testing programme on reinforced concrete columns with duplex EN 1.4462 stainless steel rebars. Three cantilever column specimens were tested, two with EN 1.4462 stainless steel reinforcing bars, subjected to constant compressive axial load plus (i) monotonic loading and (ii) lateral cyclic loading, and one B500 carbon steel reinforced control specimen. In addition, conventional pull-out tests and tensile tests were conducted for a comparative assessment of the bond-slip behaviour and mechanical properties of the reinforcing bars. Numerical modelling simulations were carried out with the open-source finite element analysis platform OpenSees to predict the nonlinear response of stainless steel reinforced concrete columns and the results were compared with the measured experimental performance data. The force–displacement global responses and the dissipated energy evolutions of the tested columns from the experimental and numerical models are presented and compared.

First published online: 22 June 2020, Tensile membrane roofs are considered to have the potential to improve the buildings’ performance due to their lightweight and flexible nature. However, their potential for improving acoustic behaviour has hardly been accurately gauged or demonstrated due to their complexity in both geometric and physical aspects. To address this issue, Carmo’s church in Lisbon—a heritage building that lost the roof during the 1755 earthquake and is nowadays a museum—was selected as case study to analyse the impact of covering high complex volumes in room acoustics by using a conventional and an alternative transparent solution: (i) a single glazing and (ii) a simple and transparent ETFE membrane tensioned in a self-supporting metal structure. This last solution is combined with a retractable cross-vaulted ceiling in a translucent and acoustic absorbent mem brane supported by pneumatic ribs. The acoustic performance for music and speech emission of these two options is compared to each other and to the existing scenario—without roof—through numerical modelling and by considering a set of selected parameters: Reverberation Time, Clarity, Early Decay Time, Speech Transmission Index and Definition (D50). These analyses allowed verifying the potential of membrane solutions to improve the acoustics of high complex volumes., Portuguese Foundation for Science and Technology (FCT - Fundacao para a Ciencia e Tecnologia), Portuguese Ministry of Education and Science (MEC - Ministerio da Educacao e Ciencia) and European Social Fund (ESF) with the reference grant SFRH/BD/104891/2014.roject UID/AUR/04509/2013 funded by FCT and MEC by national funding and FEDER (Fundo Europeu de Desenvolvimento Regional) co-financing under the new PT2020 (Portugal 2020) in a partnership agreement with Lab2PT, School of Architecture/University of Minho, Portugal.Project POCI/01/0145/FEDER/007457 funded by FEDER funds through COMPETE2020 (Programa Operacional Competitividade e Internacionalizacao) in a partnership agreement with CONSTRUCT Institute of R&D in Structures and Construction of Faculty of Engineering/University of Porto, Portugal.

The aim of this study is to deepen the technical and scientific knowledge related to the characterization of granite masonry based on geophysical tests, mechanical techniques, and neural networks. We used a nondestructive test method to characterize traditional stone masonry and further obtained data on the mechanical parameters of the elements. Historic buildings are typically constructed with stone masonry and make up the urban heritage. The maintenance and rehabilitation of historic buildings are crucial for maintaining interest in history, owing to the historical and cultural values of such buildings. The preservation of buildings classified as historical and cultural heritage is of collective interest, as they mark the history of society. Because the research object is considered a traditional structure, the use of destructive test techniques is discouraged. Thus, a mechanical characterization simulation tool using artificial neural networks (ANNs) was developed and applied to traditional granite walls. This database was developed through ground-penetrating radar (GPR) and sonic tests to characterize wall samples built. The walls were analyzed in a controlled environment, and the elastic modulus was used in response to the ANNs. Two case studies representing traditional granite masonry buildings in Portugal were evaluated through nondestructive characterization tests. For the Mancelos church and Miguel Bombarda Street building, ANNs were applied based on the sonic and GPR test results. The feasibility of using ANN simulation tools for characterizing traditional and historic buildings constructed with granite stone masonry was demonstrated.

In slope stability analysis, the high degree of uncertainty associated with design parameters has led to increasing use of reliability-based approaches as a means of evaluating the combined effects of such uncertainties on the structure performance. In this study, the reliability level of geosynthetic-reinforced steep slopes designed according to Eurocode 7 (EC7), without any additional margin of safety, was assessed using the commercially available Slide 6.0 software based on Monte Carlo simulation. To validate the EC7 partial factor design method regarding structural reliability, the estimated reliability indexes were compared with the minimum value recommended by Eurocode 0 (EC0). Additionally, through a probabilistic sensitivity analysis, the effect of variability in design parameters on slope reliability was evaluated and discussed. The results have shown that the geosynthetic-reinforced slopes designed to EC7 specifications exhibit generally an adequate reliability level according to EC0. The soil friction angle and the friction angle of the soil–geosynthetic interface and, secondly, the surcharge load, were found to be the most significant parameters for the reliability of the analysed slopes. For typical coefficients of variation of design parameters, the EC7 partial factor method tends to be conservative in terms of structural reliability. However, in situations of abnormal high variability, the partial factor methodology may lead to unsafe design, and thus reliability analyses should be implemented.

Reinforced concrete (RC) buildings in Nepal are constructed with RC frames and masonry infi ll panels. Thesestructures exhibit a highly non-linear inelastic behavior resulting from the interaction between the panels and frames. Thispaper presents an extensive case study of existing RC buildings in Nepal. Non-linear analyses were performed on structuralmodels of the buildings considered as a bare frame and with masonry infi ll, in order to evaluate the infl uence of infi ll wallson the failure mechanisms. Five three-storey buildings with different structural confi gurations and detailing were selected.The effect of masonry infi ll panels on structural response was delineated by comparing the bare-framed response with theinfi ll response. Seismic performance is evaluated with regard to global strength, stiffness, energy dissipation, inter-storeydrift, and total defl ection of the structure. A parametric analysis of structures with masonry infi ll is also performed. Forthis, the infl uence of different material properties is studied, namely diagonal compressive stress, modulus of elasticity andtensile stress of masonry infi ll panels. Study results show that masonry infi ll increases the global strength and stiffness ofthe structures; it decreases the inter-storey drift and hence the total displacement of the structure. The results quantify theinfl uence of the infi ll panels on structural response and, in particular, the effect of the diagonal compressive strength of themasonry wall.

Friction properties at geotextile interfaces play an important role in the stability of geotextile encapsulated-sand systems in coastal protection. The stabilising action of the frictional force is important to oppose sliding along the contact surface and to prevent deformations, which may lead to structural failures. This paper presents a set of experiments, based on large-scale direct shear tests performed under both cyclic loading and cyclic displacement conditions, examining friction at interfaces between geotextile specimens, sand-filled geosystem elements, and between a sand layer and a sand-filled geosystem element. The results presented here indicate that the friction parameters (i.e., shear strength and friction angle) derived from geotextile specimens are below those obtained for sand-filled elements, which suggests that using the former for the stability analysis is conservative. The tests carried out with a sand layer surface showed that a modification to the shear plane slope is likely to occur – for the sand-filled geosystem element buries into the sand layer. This deformation can result in toe instability, ultimately leading to progressive damage or even collapse of the entire structure.

The aim of this work was to study the behaviour of existing timber trusses in order to improve the knowledge that may support engineers in the definition of more adequate restoration interventions in old buildings, particularly of long-span timber structures, as industrial or monumental constructions. For this purpose, a cyclic load-carrying test was carried out on a full-scale timber planar truss rescued from an old industrial roof structure. Before the tests, an accurate geometrical characterisation was performed and the biological condition of the timber elements was evaluated by non-destructive tests to determine their effective cross-section. The results of the destructive load-carrying test were used to calibrate a numerical model with the aim of assessing the effect of the effective cross-sections of the truss components and the axial stiffness of the joints on the overall response observed during loading. The full-scale test performed proved the importance of this type of testing in assessing the behaviour of existing timber trusses. It is essential to assess the damage of the joints and to model correctly their behaviour so as to numerically reproduce the overall behaviour of timber trusses.

A framework is defined to evaluate the concrete compressive strength in existing buildings and control the uncertainty associated to the survey planning and to the concrete strength randomness. The framework proposes the discretization and disaggregation of the concrete strength in a building into finite populations of elements. Finite population statistics are used to correlate the number of tests performed in each population with the uncertainty about the mean and the coefficient of variation (CoV) of the concrete strength. A method to estimate the CoV of the concrete strength using the CoV of rebound hammer test results is also proposed to overcome the need for a high number of destructive tests. Results show that the proposed approach effectively controls the uncertainty in the estimate of the variability of the concrete strength in a population as well as the uncertainty in the estimate of the mean value of the concrete strength.

Infill masonry (IM) walls are considered to be non-structural elements but, when subjected to earthquakes, they tend to interact with the surrounding RC (reinforced concrete) frames, which can result in different failure modes depending on the combination of the in-plane and out-of-plane behaviour. Therefore, the contribution of IM panels should be considered in the structural response analysis of existing buildings, for which an understanding of the out-of-plane non-linear behaviour of IM walls is of paramount importance in order to develop efficient strengthening solutions to prevent collapse and improve their performance in future earthquakes, and consequently reduce their seismic vulnerability. In order to obtain further knowledge of the out-of-plane response of IM panels, a study of full-scale IM walls was carried out with the realization of three experimental (cyclic and monotonic) out-of-plane tests with and without previous in-plane damage. The experiments, material characterization and the test set-up will be described in this paper as well as presenting and discussing the main test results, namely in terms of hysteretic force–displacement curves, damage evolution, stiffness degradation and energy dissipation.

Bridge damages during the past earthquakes caused several physical and economic impacts to transportation systems. Many of the existing bridges in earthquake prone areas are pre-1990 bridges and were designed with out of date regulation codes. The occurrences of strong motions in different parts of the world show every year the vulnerability of these structures. Nonlinear dynamic time history analyses were conducted to assess the seismic vulnerability of typical pre-1990 bridges. A family of existing concrete bridge representative of the most common bridges in the highway system in Iran is studied. The seismic demand consists in a set of far-field and near-field strong motions to evaluate the likelihood of exceeding the seismic capacity of the mentioned bridges. The peak ground accelerations (PGAs) were scaled and applied incrementally to the 3D models to evaluate the seismic performance of the bridges. The superstructure was assumed to remain elastic and the nonlinear behavior in piers was modeled by assigning plastic hinges in columns. In this study the displacement ductility and the PGA are selected as a seismic performance indicator and intensity measure, respectively. The results show that pre-1990 bridges subjected to near-fault ground motions reach minor and moderate damage states. (c) 2016, The Author(s).

Cork is a natural material that has always been associated to mankind having huge potential and many uses. The cork industry worldwide consumes more than 280,000 t of cork a year. However, about 20% to 30% of the raw cork received at the processing units is rejected, mainly as cork dust. Finding useful applications for the rejected cork may have important economic and environmental implications. Trying to combine the advanced technology of self-compacting concrete and use of this waste from the cork industry, this study concerns the possibility of using cork powder as a substitute for fines in mixtures of self-compacting concrete. An experimental program was carried out to assess the behavior of this material in the mixture and define properties in terms of strength and durability of self-compacting concrete containing cork powder. It was found that it is possible to use an abundant waste material from the cork industry, cork powder, as fines in Self Compacting Concrete resulting in a good strength level (C 30/37) and suitable durability for common applications. Keywords: Cork waste, Self-compacting concrete, Mortar, Fines, Durability

A study on the time development of local scour around a complex pier was developed using a small-scale model embedded in a sediment bed. A total of 15 laboratorial tests were performed at the Hydraulics Laboratory of the Faculty of Engineering of the University of Porto. The duration of each experiment was previously established to progressively characterize the scour cavity. After each experiment, the flume was gradually emptied to facilitate the application of close-range photogrammetry. The scour depth values resulting from the application of photogrammetry at the pile cap front agree well with the values obtained experimentally. The temporal development of the scour cavity is presented and discussed. Empirical formulas for the scour cavity time development and for the relation of scour depths to scour cavity volumes were obtained. The obtained three-dimensional models can also be used for calibration and validation of numerical models.

This research evaluates which is the most cost-efficient rainwater harvesting (RWH) system in a new commercial building located in the north of Portugal, in Braga. Based on the economic analysis, the cost-efficiency of the presented RWH strategies may be considered for the case studied. The results of this research indicate that RWH scenarios proposed are cost-efficient. Considering a 10 % discount rate, the water price charge in the municipally of Braga and the cost of the infrastructures would be enough to make RWH cost-efficient for this option. At this discount rate, the payback period ranges from 2 to 6 years and the internal rate of return would range from 23 to 76 %. If a discount rate of 5 % were considered, the payback periods would be reduced by approximately 1 year.

Purpose – Infrared thermography is increasingly being used to diagnose pathologies in buildings, such as façade defects. The purpose of this paper is to assess the results reproducibility and the equipment influence on the measurements. To do so, it was defined as case study the assessment of rendering delamination. Design/methodology/approach – Two infrared cameras of different makers were used to detect the presence of defects deliberately created in specimens. The tests were done in the laboratory with a heat source. The defects were detected through a temperature gradient between the zones with and without defect. Findings – With this thermographic imaging, it was possible to identify the defects in the specimen both qualitatively and quantitatively. The results were found to be reproducible in the three cycles performed. The influence of the equipment on the results was of little significance for the quantitative assessment criterion “temperature difference between zones with and without defect”, but for the criterion “absolute surface temperature”, the difference in the results yielded by the two cameras was around 1.8°C. Originality/value – The results suggest that there is reproducibility of the measurements, considering both the qualitative and quantitative approach, when assessing delamination, irrespective of the maker of the equipment used. The influence of the equipment on the results depends on the quantitative assessment criterion used.

As the oil refining industries continue to grow, the production of waste catalysts generated in that process is expected to also increase. It would be of great value both economically and ecologically if these wastes could be reused as an addition in self-compacting concrete (SCC). This paper uses statistical factorial design approach, namely a central composite design, to conduct a proper experimental plan to design SCC mortar mixtures incorporating spent equilibrium catalyst (ECat), a waste generated by the oil-refinery industry. The mathematical empirical models derived (which were also experimentally validated) revealed the influence of mixture design parameters, and their coupled effects, on the mortars’ properties namely, deformability, viscosity, compressive strength, resistivity and ultrasonic pulse velocity. A numerical optimization technique was applied to the derived models to select the best mixture, which maximizes simultaneously durability and eco-efficiency and minimize cost, while maintaining self-compactability. The current study revealed that ECat can be successfully applied in SCC mortars, as a high volume cement replacement material (up to V E c a t / V p = 19.7%) due to its high pozzolanic activity. Nevertheless, for powder-type SCCs, cement/ECat blends must be combined with other finer additions to complete the powders distribution curve increasing the viscosity and stability of paste phase, in the fresh state.

Summary Considerable efforts have been made towards the development of robust and fully automated vibration-based monitoring systems with the goal of extracting relevant information regarding the dynamic behaviour and health condition of the monitored structure. Satisfactory results have been obtained in this scientific domain by combining accurate measurement systems and fully automated output-only modal identification techniques. In this context, the main objective of this contribution is to demonstrate in a full-scale case study that with the application of sophisticated algorithms for the automatic tracking of modal parameters, it is possible to detect very small structural changes. Apart from describing the main features and capabilities of the autonomous monitoring system implemented to assess the structural condition of a peculiar football stadium suspension roof, this paper also outlines the main results obtained over the course of 4 years of monitoring carried out to assess the dynamic behaviour and the health condition of the roof structure. The routines developed for the online processing of the continuously collected acceleration time series include state-of-the-art processing techniques, such as automated modal identification based on cluster analysis and principal components analyses combined with control charts for removal of environmental or operational effects and detection of structural changes, together with some innovative features in the context of continuous dynamic monitoring, such as the quantification of the uncertainties associated with each modal estimate and the estimation of the contribution of each mode to the measured structural response.

This paper describes an extensive experimental investigation conducted on the Braga Stadium suspension roof combining recent developments in terms of sensors, data communicating systems, computational power and automated output-only modal identification algorithms. The continuous monitoring program established around this outstanding structure has allowed the continuous measurement of wind, temperature and acceleration. The variation of such quantities during a period of 8 months has been investigated, with the purpose of obtaining a characterisation of the wind action based on field tests, establishing correlations with the structural response and finally analysing the influence of wind and temperature on the variation of modal parameters.

Road safety research, in particular road and traffic safety evaluation research, is highly applied and carried out mostly to help reducing the number of road accidents and the injuries resulting from them. This subject has been continuously studied, and in developed countries road safety is improved in a way that, more and more, new measures have less visible impact. Although measures are usually taken directly in the source, which makes all the sense, it is possible to reduce the accident impact if improvements are made "a posteriori"; this is, improving the emergency system to minimize the socioeconomic impact of the accident. In order to study accidents impact it is necessary to merge two different datasets - police and hospital. This process is known as data linkage and besides a manual linkage process there are three main numerical methodologies: deterministic record linkage, fuzzy matching and probabilistic record linkage. Because these types of datasets are usually protected by anonymity, unique identifiers are not possible to achieve, thus the probabilistic record linkage is usually the chosen method. This paper presents a concept for an algorithm based on the databases' demographics. By analyzing the various demographic fields it is possible for the algorithm to calculate individual weights that depend on the occurrence of each fields' values among a specific dataset. The demographics are based on the case of Gaia's city road record accidents. (C) 2014 The Authors. Published by Elsevier B.V.

The influence of the infill masonry walls in the structural response of reinforced concrete (RC) structures when subjected to earthquakes is not considered in Nepal National Building code and Indian Standard code. Field observations carried out after the 25th April Gorkha earthquake in Nepal reinforce the importance of the infill walls, namely, through the significant increasing of the structural stiffness and by the possibility of introducing unexpected mechanisms that can cause extensive damages or even the collapse of the structure. This article focuses on the study of an existing bare frame, representative of the Nepalese RC buildings, which was modeled and calibrated with data results collected from ambient vibration tests. Initially, a parametric study was conducted with the aim of evaluating the influence of parameters, such as concrete strength and elasticity modulus, slab thickness, and columns cross section in the natural frequencies of the building. The influence of the infill masonry walls in the structural response was evaluated through the modeling of three different numerical models with different disposition of the infill panels from the calibrated existing structure. The seismic vulnerability assessment was performed through non-linear static pushover and dynamic analysis. The results will be presented and discussed in terms of base maximum inter-storey drifts and maximum base shear.

Ancient buildings in historical town centers can be protected by Cultural Heritage legislation, thus implying that any rehabilitation must respect their main architectural features. These concerns also apply to Modern and Contemporary buildings, in particular if they are important examples of architectural styles from those periods. These extra problems, or motivations, add to the inherent structural delicacy of ancient building restoration that requires detailed knowledge of the building foundations, characteristics and materials, modification history, infrastructure mapping, current pathologies, etc., all relevant information for an informed rehabilitation project. Such knowledge is seldom available before the actual rehabilitation works begin, and the usual invasive preliminary surveys are frequently expensive, time-consuming and likely significantly alter/damage the building's main features or structural integrity. Hence, the current demand for indirect, non-invasive, reliable and high resolution imagery techniques able to produce relevant information at the early stages of a rehabilitation project. The present work demonstrates that Ground Penetrating Radar (GPR or Georadar) surveys can provide a priori knowledge on the structure, construction techniques, materials, history and pathologies in a classified Modern Age building. It is also shown that the use of GPR on these projects requires carefully designed surveys, taking into account the known information, spatial constraints, environmental noise, nature and dimensions of the expected targets and suitable data processing sequences. Thus, if properly applied, GPR produces high-resolution results crucial for sound engineering/architectural interventions aiming to restore and renovate Modern and Contemporary buildings, with (1) focus on the overall quality of the end-result, (2) no damage inflicted to the existing structure, (3) respect of the building's historical coherence and architectural elements and characteristics, that is, its Cultural Heritage value. Most of the findings and applications discussed in this work can be seen as an approximation to model studies, so that, relevant information can be drawn from the different investigated situations. Therefore, owing to the nature and the range of the problems encountered in this case study, it is also expected that the presented GPR data and interpretation will provide important clues and guidance in the planning and investigation of similar projects and problems.

Adobe construction was very common in Aveiro district, Portugal, until the middle of the 20th century. At present, there are still many adobe buildings in use, a significant percentage of which have social, cultural, and architectural value. Many of these buildings, however, are in a poor state of conservation. The existing problems are partially the result of a lack of knowledge about the materials and building systems traditionally used. To contribute to this knowledge, a visual and dimensional inspection of the facade walls of twenty one adobe buildings located in Anadia, Murtosa, and Aveiro municipalities, in Aveiro district, was conducted. This article presents a description and analysis of the construction details, common defects, and state of conservation of the facade walls studied. This work aims to contribute with preliminary information that may help support the preservation and rehabilitation of existing adobe buildings.

The fundamental frequency of a structure enables better assessment of its seismic demand for an efficient design and planning of its maintenance and retrofit strategy. The frequency is independent of the type of external loads, however, depends on structural stiffness, mass, damping and boundary conditions. In the case of slender masonry structures such as towers, minarets chimneys, and pagoda temples, it is influenced by mass and stiffness distribution, connection to adjacent structures, material properties, aspect ratio and slenderness ratio. In this present article, the data collected from various literature reviews on the slender masonry structures regarding dynamic, geometrical, and mechanical characteristics have been correlated to identify the major parameters influencing the fundamental frequency of such structures. The database has been used for developing an empirical formulation for predicting the fundamental frequency of such structures. The comparison between the experimental fundamental frequencies and the estimated fundamental frequencies are carried out in order to define reliability and accuracy of these empirical formulae.

This work describes the development and implementation of a structural health monitoring system on a stress-ribbon footbridge. In a first part, it characterises the implemented continuous dynamic monitoring system and the application of automated operational modal analysis to analyse the variation of modal properties estimates along several years. A correlation analysis is then conducted showing that environmental and operational factors (e.g. temperature and pedestrian traffic) induce significant nonlinear effects on the modal frequency estimates, which may mask subtle early damage. Taking into account linear relations between frequency estimates of different modes, the linear Principal Component Analysis (PCA) is applied to remove those effects. Novelty analysis of the residual errors of PCA is used to build a statistical damage indicator for long term structural health monitoring. Finally, the efficiency of the described damage detection methodology is evidenced by simulating some realistic damage scenarios based on an experimentally validated finite element model and observing the clear deviation of the damage indicator. It is demonstrated that such a dynamic monitoring system can serve as an effective tool for long term bridge health monitoring.

The analysis of slender reinforced concrete box-girder webs, in bridge decks, must be carried out considering the effects of in-plane shear and transverse (out-of-plane) bending. In the case of structures subjected to important cyclic loads, such as railway bridge decks, fatigue must also be taken into account. This paper presents a numerical methodology for fatigue analysis of reinforced concrete girder webs, considering the combined effects of in-plane shear and transverse bending. Fatigue lives are calculated by using the damage accumulation method, which makes it possible to analyse variable amplitude stress histories due to real traffic. The main specificity of the proposed methodology lies in the algorithm for calculation of stress histories in the stirrups and in the web concrete. This algorithm is validated through the comparison with experimental results reported in the bibliography, which demonstrates that the proposed approach provides results on the safe side. The interest and practical consequences of employing this methodology in fatigue analyses of new structures are illustrated through the application to a real case study.

The geometrical track degradation is characterized by the evolution over time (or tonnage) of several parameters such as the longitudinal level, the alignment, the gauge, the twist and the cross level. Dynamic track inspections allow monitoring the track geometrical quality which is essential to ensure track availability and reliability, passenger safety and comfort and also energy efficiency. The track geometrical quality is guaranteed by performing condition-based maintenance and renewal actions during the life of the track and for that it is crucial to understand the geometrical track degradation process. In this paper, a stochastic model for characterizing the geometrical track degradation process over time is presented. The Portuguese railway Northern Line is adopted as a case-study and a statistic analysis is performed for different vehicle speed groups, in accordance with CEN [1] . The new contribution of this research is that the Dagum distribution, usually adopted for representing the income distribution, may represent the geometrical track degradation process in terms of the longitudinal level.

The transportation planning process is considered to be the initial step to incorporate the safety analyses of a transport system. Recently, tools have been created for this incorporation, although the vast majority has been applied at an area level. Despite the capacity of these tools to provide safety information, they are unable to identify hazardous locales in the network. The primary objective of this article was to develop a tool based on accident prediction models, which enable the forecasting of the highest accident-risk entities (i.e., nodes or links) using the information available as well as meeting the main issues that are decided at the planning level. Analyzing the influence of macrolevel road design variables on accident risk was the second objective, providing knowledge for planners and decision makers. To accomplish these objectives, generalized linear modeling techniques were employed to develop models for nodes and links using data from Porto, Portugal. The result analysis demonstrates that the additional macrolevel variables are statistically significant and improves the model. Thus, the results lead to a general conclusion that the proposed models are the suitable tool because they embody the balance between the needs and constraints inherent to the planning level. © 2013 Copyright Taylor and Francis Group, LLC.

Although there is a considerable number of freight traffic assignment models available, they still tend to lag behind their passenger counterparts in terms of maturity of their scientific knowledge. In order to contribute to the improvement of this state of affairs, the authors developed an innovative traffic assignment model, intended to model large networks with a strategic level of planning, which considers both road and rail transport modes and is not very demanding in terms of data. The model applies two different assignment techniques for the two types of cargo considered, with its main innovative feature being the fact that it takes into account both capacity constraints and a variable perception of costs by users, while being much simpler and lighter than a stochastic user equilibrium model. The simultaneous consideration of both of those factors distinguishes it from the traditionally used traffic assignment techniques, namely all or nothing, equilibrium or stochastic (multi-flow) techniques, none of which considers those factors simultaneously.

An optimization model for a rail freight network was developed as a support tool for planning and policy decisions involved in the improvement of rail networks on a regional and national level. The model was based on a strategic traffic assignment model, which was designed to model macronetworks with a high aggregation level, and was exclusively designed for freight traffic. The model contemplates road and rail transport modes and considers two types of cargo: intermodal cargo, which is generally transported in containers and is easily interchanged between different modes at intermodal terminals, and general cargo, which represents all the remaining cargo. The optimization process was based on a local search heuristic that delivers good solutions in a reasonable computing time. The quality of each network improvement solution was assessed on the basis of the reductions in total generalized costs and carbon dioxide emissions. This optimization model for a freight network is innovative because it is not limited: both the improvement of existing links and the construction of new ones are allowed, and the model does not have a limit on the number or variety of possibilities for network improvement. The adaptability to different conditions was emphasized when the model was applied to two networks under different investment scenarios because the model delivered considerably different solutions adapted to the conditions of each scenario.

The most efficient strategy to ensure long-term road network safety is to integrate safety analysis into the planning process of a network or a corridor. Safety planning decision-support tool outcomes should be reliable and realistic, taking into account the main characteristics of this particular level, which is characterized by scant and generalized data. However, the tools developed and presented in previous studies are based on models with a quantitative response. To develop a more suitable tool while maintaining a measure assessment character, this work presents a qualitative response model whose outcome is the risk of occurring three degrees of hazards: low, medium, and high. In this study, an ordered probit model was applied to an urban road network using Porto city data. Hazard categories were defined using accident frequency to reflect a measure of the safety of the road network studied. The developed model provides a safety risk analysis considering road data that are easy to gather or estimate at the planning level. In addition, an analysis of hypothetical scenarios for two sample segments is presented to illustrate an application of the categorical model in typifying an accident risk analysis at a planning level. © 2012 Copyright Taylor and Francis Group, LLC.

The approach to spot speed prediction in two-lane highways followed in this study aims to evaluate the effects of a comprehensive set of speed factors, with a special focus on the geometric characteristics of the road segment to which the element belongs. Two flexible models were developed for different types of roads based on a stochastic frontier formulation in which the maximum operating speed is estimated as a function of road geometrics, and the one-sided disturbance accounts for diversity in driving behavior and vehicle characteristics, allowing the estimation of any percentile speed. The models are applicable to horizontal curves and tangents and consider both on-site characteristics and aggregated variables characterizing the road segment. The results show a clear influence of segment features on different percentile spot speeds, revealing that recent driving experience and expectations about the quality of the geometric design influence the way a driver approaches a specific road element. Additionally, this study contributes to addressing some of the limitations of existing speed models identified in the literature.

Advances in the development of sensors, data processing systems, and numerical models have motivated the implementation of structural health monitoring (SHM) specially focused on the assessment of structural safety. Thus, this work presents a literature review about SHM platforms, especially from 1993 to 2015. In this way, a short history review about the recent advances on SHM, mainly related with dynamic monitoring, was summarized, and a benchmark and the main guidelines related with SHM platforms were also included in this review. Some case studies are also described here. Special attention was given to SHM platforms, and a method for their classification (an extension of Rytter’s method) is presented. In addition, experiences related with heritage constructions, specially focused on maintenance, were included in this work. In the final section, some observations are made about the new prospects for SHM. The recent advances on SHM platforms contributed to the development of adaptive systems and to the cost reduction of the monitoring systems implementation, allowing the increase of its application in real structures. However, the monitoring systems should be implemented, optimizing all the available sensing technologies.

The sustainable rehabilitation of an historical construction can only be achieved if there is adequate knowledge about its state of conservation. To obtain such knowledge, reliable structural survey and diagnosis procedures need to be employed. An overall definition of the more important technical procedures that need to be considered is addressed to provide general guidelines for the structural survey and diagnosis of historical constructions. A more detailed description of some of the methods is then also performed. Several case studies are then presented to illustrate these approaches, emphasizing the importance of the technical inspection and survey data in the rehabilitation actions that were developed in each case study.

Optical systems are recognized to be an important tool for structural health monitoring, especially for real time safety assessment, due to simplified system configuration and low cost when compared to regular systems, namely electrical systems. This work aims to present a case study on structural health monitoring focused on reliability assessment and applying data collected by a simplified optical sensing system. This way, an elevated reinforced concrete water reservoir was instrumented with a bi-axial optical accelerometer and monitored since January 2014. Taking into account acceleration data, the natural frequencies and relative displacements were estimated. The reliability analysis was performed based on generalized extreme values distribution (GEV) and the results were employed to build a forecast of the reliability of the water elevated reservoir for the next 100 years. The results showed that the optical system combined with GEV analysis, implemented in this experimental work, can provide adequate data for structural reliability assessment. RESUMO Sistemas óticos são reconhecidos como uma importante ferramenta para a monitorização estrutural, especialmente para avaliação da segurança em tempo real, devido a configuração simplificada e o baixo custo destes sistemas quando comparado com sistemas usuais, nomeadamente sistemas elétricos. Este trabalho tem por objetivo apresentar um caso de estudo sobre monitorização estrutural focado na avaliação da fiabilidade através da utilização de um sistema sensorial ótico simplificado. Dessa forma, um reservatório elevado de água de concreto armado foi instrumentado com um acelerómetro ótico biaxial e monitorado desde janeiro de 2014. Tendo em conta os dados de aceleração, as frequências naturais e os deslocamentos relativos foram calculados. Neste trabalho, a análise de fiabilidade é realizada baseada na distribuição de valores extremos e os resultados obtidos são ainda utilizados para a predição sobre a segurança estrutural do reservatório de água para os próximos 100 anos. Os resultados mostraram que o sistema ótico de monitorização implementado neste trabalho combinado com a análise por distribuição dos valores extremos pode fornecer dados adequados para a avaliação da fiabilidade estrutural.

Geosynthetic-reinforced load transfer platforms are commonly used in constructions over column-reinforced soft soils and correspond to modifications of conventional granular load transfer platforms that utilise only the arching effect of the granular soil to transfer the loads onto the columns. Both a single geosynthetic layer and several geosynthetic layers can be used to reinforce the granular soil of a platform. Most of the studies published in the literature address the use of single geosynthetic-reinforced platforms, while there is a lack of studies on multilayer geosynthetic-reinforced platforms. In the present study, to help overcome that lack, a jet-grout column-reinforced soft soil foundation with a platform that incorporates five geosynthetic layers is analysed. A parametric study is also performed in order to analyse the influence of four key factors. A numerical code based on the finite element method is used, incorporating a fully coupled analysis and soil constitutive relations simulated by the p-q-θ critical state model. The study mainly shows that a larger number of geosynthetic layers within the platform brings about better geotechnical behaviour of the column-reinforced soft soil foundation in terms of the settlement and the load transfer onto the columns.

Exterior insulation and finish systems (EIFSs) are common in Europe nowadays. These systems bring thermal benefits, in addition to being cheap and easy to apply, but there are often serious problems with biological growth, causing cladding defacement. The physical phenomenon causing EIFS defacement is known, and mathematical models simulating its performance have been developed. However, no simple process exists to evaluate the risk of EIFS surface humidification (which contributes to surface defacement) that might be used by designers and by the building industry. This paper presents a methodology to assess EIFS surface humidification based on the definition of indices that combine the effect of surface condensation, wind-driven rain, and the drying process, three of the most prevalent parameters influencing surface moisture content. The proposed indices were calculated using data collected during a 1-year in situ test campaign, which provided information about the exterior climate conditions and the surface temperature and wind-driven rain on four EIFS-covered facades facing the cardinal directions. The indices were compared with the results of the surface moisture measured simultaneously, which allowed the methodology to be validated. This paper also presents an example of the practical use of this methodology using a definition of hazard classes of surface humidification of EIFS-covered facades located in Portuguese territory.

Reinforced concrete frames infilled with masonry panels without proper seismic design can protect or potentiate the risk of structures when subject to earthquakes. This paper presents two case studies of existing reinforced concrete buildings with masonry infill panels located in Portugal in different seismic zones according with the EuroCode 8. The RC buildings were studied with and without the infill panels using non-linear dynamic analysis, comparing the different seismic response in terms of global storey displacements, inter-storey drifts, storey shear and ductility demands in the columns. The results show that in one building it is safe and conservative not to take the panels into account, however in the case with irregular infill distribution in elevation the results are significantly different and the presence of the infills plays and important role.

Earthquakes which recently occurred in highly populated regions show that existing buildings constructed without appropriate seismic resisting characteristics may constitute as an important source of risk and may cause economical loses and casualties. It is recognized the progress of the knowledge in earthquake engineering in the last decades. In this paper, two 6 irregular storey buildings were studied consisting of frame structures, representative of the common practice in Portugal, i.e. designed without considering earthquake actions. Push-over and non-linear time history analyses were done, with non-linear 3-D models in longitudinal and transverse directions. The building responses were analyzed in two different levels: global and local. For the global response analyses: max displacement, inter-storey drift (IS drift), floor rotation for each storey and base shear were compared. For local response four columns were chosen and the variation of axial load in terms of base shear and drift as well as the biaxial demand was considered. The result shows that most variation of axial load happens in corner, facade-X, facade-Y and centre column respectively. It is noteworthy that by increasing the initial axial load the biaxial demand decreases. The seismic vulnerability was analyzed for earthquake of different return periods, and the seismic demands were compared with limit proposed in international codes and conclusion are drafted in terms of safety. The vulnerability assessment based on seismic codes clearly shows that the building 2 presented a better performance with low inter-storey drifts. The main goal of this study is considering the application and methodology for the seismic assessment of existent real buildings. In fact this is an important topic, to understand the seismic vulnerability of certain particularities in existing buildings to assure that the common observation can be applied for a prototype building, especially irregular ones. Also one of the major observations in this study is the comprehension of the effect and importance of biaxial loading in columns and the influence of the axial load variation, relating the position of the columns in plan and in height.

Using realistic constitutive models for artificially cemented soils is advantageous in design. However, the price of that increased realism is often a more elaborate model, which is difficult to calibrate. A database of high quality triaxial tests on compacted cemented silty sand is used to calibrate and validate a generalized critical state bonded soil model. The exercise highlights the staged calibration procedure that is convenient in this kind of application. The calibration results have shown a direct relation between added yield strength and a well-established soil–cement mixture ratio, which facilitates the application of the model in design. It is shown that such relation can be also deduced from the analysis of unconfined compressive strength tests.

This article presents a field experimental campaign carried out on an existing one-story stone masonry building, aiming at characterizing the out-of-plane behavior of its walls. A bidirectional test set-up based on a self-equilibrated airbag system was developed and used on three similar masonry walls under distinct conditions: original, retrofitted, and strengthened. The results obtained and the main advantages and shortcomings found in the test set-up are discussed. Finally, some of the most popular retrofitting and/or strengthening techniques applied during the 1998 Azores reconstruction process are critically analyzed, aiming at suggesting quantifications for future interventions on existing unreinforced masonry buildings.

New material safety factors (CF mat ) are proposed to characterize material strength in existing buildings. These safety factors are developed in order to be compatible with seismic safety assessment procedures defined by current standards such as Eurocode 8 Part 3. The general theory behind the development of the CF mat safety factors considers the uncertainty associated to the number of surveyed structural elements and the inherent variability of the material strength under analysis. The CF mat safety factors are developed using a finite population approach where the material properties in a building are discretized by considering one value per element. The proposed theory is used to define specific CF mat values and survey plans for the concrete compressive strength and for the reinforcing steel yield strength.

The paper describes two dynamic monitoring systems installed in lively footbridges with the purpose of characterizing the dynamic behavior and response of these structures and possibly detecting damage at early stages. Some monitoring results illustrate the capabilities of the presently existing technology.

In recent years environmental sustainability has demanded a progressive increase of waste recycling in general and waste value-added utilisation in the construction industry in particular. As regards the application of construction and demolition wastes (C&DW) in geotechnical works, it has been noticed that the use of recycled aggregates is found mostly in road construction. Value-added utilisation of C&DW in geosynthetic-reinforced structures is almost an unexplored field. This paper presents the results of physical, mechanical and environmental characterisation of recycled C&DW, as well as the direct shear behaviour of three recycled C&DW–geosynthetic interfaces. The C&DW material was collected from a recycling plant and came from the demolition of single-family houses and the cleaning of land with illegal deposits of C&DW. Two geogrids and one geocomposite reinforcement (high- strength geotextile) were used to assess the behaviour of C&DW–geosynthetic interfaces. The environmental characterisation of the C&DW, carried out through leaching tests, did not show environmental concerns. Direct shear test results have demonstrated that properly selected and compacted C&DW can exhibit shear strength similar to natural soils. The coefficients of interaction achieved for C&DW–geosynthetic interfaces compare well with those reported in the literature for soil–geosynthetic interfaces under similar conditions, which supports the feasibility of using these recycled materials as backfill in geosynthetic-reinforced structures.

INTRODUCTION: The most common measurement for road accidents relies in police reports; however, there is a high portion of underreporting and misclassification, mainly concerning elderly causalities, urban accidents, slightly injured, users of two-wheeled vehicles, and car occupants. METHODS: In order to assess these issues, road accidents occurring in the Porto Metropolitan Area, Portugal, covering a 6-year period (2006-2011) were analyzed based on police and hospital datasets. By linking hospital data with police data, it is possible to evaluate the misclassification of the victims' severity by the police regarding the maximum abbreviated injury scale (MAIS) classification. Additionally, considering that 29% of the victims recorded by hospitals were not reported by the police, which is in line with the reality of other EU countries, underreporting is further investigated. Thus, we used econometric and statistics tools to measure the correlation between different available data to identify possible causes of underreporting and misclassification. In this sense, factors contributing to the misclassification of casualties by the police are identified using a univariate analysis. On the basis of the linked police-hospital data, and considering those factors and the police classification, a probabilistic model was developed to estimate a MAIS-based classification for all individuals included in the police accident records. RESULTS: The results of misclassification indicate a significant over-classification of severe injury by the police. Additionally, a systematic police underreporting phenomenon of around 30% was found. CONCLUSIONS and Practical Applications: Finally, comparing estimated results and actual data, we were able to produce non-fatality adjustment coefficients to estimate the total casualties taking into account the underreporting and misclassification phenomena and to compare them with the Portuguese and European realities.Copyright © 2016 Elsevier Ltd and National Safety Council. All rights reserved. Language: en

A simplified risk assessment framework specifically developed for built immovable cultural heritage assets is proposed. The framework addresses all the components in a risk analysis and can be used as a screening procedure for the preliminary assessment of a large number of assets with limited resources. Furthermore, the framework can also be used to identify cultural heritage assets that require a more refined and resource demanding risk evaluation. The proposed risk analysis framework falls into the category of qualitative methods and is based on an existing approach developed for the vulnerability assessment of critical infrastructures. The qualitative risk analysis of the proposed methodology is based on a set of structured assessment flowcharts that address the main components of a risk analysis: the likelihood of the hazard, the vulnerability of the asset to the hazard, the consequences of the hazard, the loss of value of the asset and the capacity to recover from the event. To illustrate the applicability of the proposed methodology, an application example is also presented for the case of seismic risk.

Masonry is a structural material that presents a quite complex behaviour that depends on the mechanical and geometrical characteristics of the units, the mortar and the link between these two elements. In particular, the characterization of the shear behaviour of masonry elements involves proper experimental campaigns that make these analyses particularly expensive. The main objective of this paper is to present a case study on the characterization of the shear behaviour of masonry through a methodology that merges a small number of laboratory tests with computer simulations. The methodology is applied to a new masonry system that has recently been developed in Portugal, and involves a FEM numerical approach based on micro3D modelling of masonry samples using nonlinear behaviour models that are calibrated through a small number of laboratory tests. As a result, the characterization of the masonry shear behaviour trough this methodology allowed simulating, with reasonably accuracy, a large set of expensive laboratory tests using numerical tools calibrated with small experimental resources.

Performance-based earthquake engineering methodologies often require a probabilistic model of structural demand. Since observations masking the probability distribution of the majority of the data are frequently found, robust estimation methods are proposed to estimate the probabilistic model parameters (i.e., central value and dispersion). The performance of thirty-three robust dispersion estimators is evaluated, for different sample sizes, using the chord rotation, curvature, shear force, and inter-story drift demands obtained after analyzing five reinforced concrete structures under real earthquake records scaled to several intensities. Based on the results, combinations involving dispersion and central value (defined in a companion article) estimators are proposed.

Speed choice is strongly influenced by geometric road features. In this work, the influence of lane and shoulder widths on free-flow speed was studied with the driving simulator DriS at the University of Porto in Porto, Portugal. To evaluate how speed was influenced by the cross section, this study investigated the possible influence of the order of magnitude of the practiced speeds on the effects of variations in lane and shoulder widths. Two types of roads with different base speeds were considered. The roads were presented to drivers on a driving simulator. The validity of the data obtained in the simulator was confirmed through a comparative analysis of the registered speeds in the real environments for the equivalent simulator conditions at six points of control. The lane and shoulder widths from which the free-flow speed was no longer conditioned by the dimensions of the road's cross section were obtained, as well as the reduction in speed associated with smaller widths. Contrary to what was suggested by the Highway Capacity Manual 2010, the individual effects of variations in lane and shoulder widths were not cumulative; greater impacts on free-flow speed were obtained by their simultaneous variation.

In developed countries, the building sector is responsible for a very significant share of the total energy consumption. School buildings, because they are places where children are educated and learn to become active members of the society, should be a good example of an efficient use of energy and water. In this study, data of the energy and water consumption of 23 Portuguese schools and their main building characteristics and properties were gathered. This information was normalized to homogenize the data set and then analyzed using advanced clustering techniques. The results show a significant variability in the consumption of different schools, even with similar characteristics, suggesting that the user behavior plays an important role in their efficiency. The complete linkage and Ward's clustering methods were applied, both produced three clusters, and reference values for electricity and water consumption were defined. (C) 2014 American Society of Civil Engineers.

Masonry structures can be considered as the simplest type of structures concerning its assemblage but, at the same time, it is one of the most complex construction materials in terms of mechanical properties and correct behaviour assessment. In this context, the work herein presented aims at describing an experimental testing campaign recently carried out in order to characterize the out-of-plane behaviour of traditional masonry constructions. Taking advantage of the existence of a traditional two-storey masonry building abandoned after the 1998 Azores earthquake, several in-situ tests were defined and performed with the application of quasi-static cyclic loads at the building top level in the out-of-plane direction. In addition, the efficiency of retrofitting and/or strengthening techniques applied during the 1998 Azores reconstruction process was also experimentally evaluated. Finally, an overall discussion of these techniques is presented, resorting also to previous tests' results carried out by the same authors, aiming at inferring and suggesting quantifications of strengthening techniques' contributions for future interventions on existing buildings. For this purpose, simple analytical mechanical approaches were adopted in order to provide numerical estimates of strength that were found in good agreement with the experimental results. (c) 2011 Springer Science+Business Media B.V.

The paper describes a study to characterize intentional human dynamic loads (vandal loads) and their induced effects on a footbridge. A numerical model to characterize the dynamic behavior of the footbridge has been developed, is experimentally validated, and is used to numerically simulate the response induced by groups of pedestrians synchronized at critical bridge frequencies. The vandal load associated with a single pedestrian is characterized and compared with definitions in the literature. The response is then calculated considering the measured load and compared with the measured response to the excitation induced by a single pedestrian or a group with varying dimensions. The definition of a general load model for vandal excitation, including a tentative definition for synchronization is discussed.