Existing performance assessment methods for structures subjected to flow-type loading (i.e., flood, tsunami) rely on assumptions and previous knowledge derived from other hazards, such as earthquakes. However, flow-type induced loads on structures are fundamentally different in nature from seismic action, inducing long-duration non-uniform pressures on inundated components. Flume or wave basin tests on large-scale structural components under fluid loading are limited due to the difficulties in scaling. The present paper proposes a novel quasi-static testing method for performing full-scale tests on masonry infill walls in reinforced concrete (RC) frames subjected to simulated flow-type loading in a structural laboratory setting. The innovative test set up involves the use of an array of 28 pneumatic actuators and a novel testing procedure (i.e. test set-up and load protocols) is developed for simulating quasi-statically flow-type induced loads with increasing flow depth on full-scale building components. The feasibility of the proposed testing method is herein demonstrated on four full-scale masonry infill walls (dimensions 4.2 m x 2.3 m) in RC frames. The tests allow for the out of plane (OOP) performance of masonry infill walls to be assessed under flow-type loading conditions with increasing flow depth. Masonry walls are tested with and without plaster to point out the effect of the latter on the overall capacity of the wall. Original experimental data from flow-type testing are presented and discussed to provide insights into the OOP capacity of infill walls under flow-type loading. Finally, the OOP performance of infill walls under flow-type loading is compared with that of the same specimen previously tested under seismic loading conditions. Results attest the feasibility of the proposed testing method to characterise the structural response of full-scale building components under flow-type loading.

This paper reports on a numerical study focused on the characterization of the masonry and infill material behaviour of stone arch railway bridges. The study is based on experimental data from testing campaigns carried out in materials of two granite stone bridges. The campaigns comprise lab tests on stone masonry samples (blocks and joints) collected from the bridge structure, as well as in-situ flat-jack testing and Menard pressuremeter tests on masonry and infill components, respectively. A strategy was developed resorting to Finite Element (FE) methodologies involving local scale numerical simulation of the joint lab tests (shear tests) and both in-situ tests (Flat-jack and Menard pressuremeter tests), aiming at the calibration and validation of the material parameters to be used in global scale numerical simulations of the bridges' structural behaviour. The joint shear behaviour is simulated using a FE discrete formulation based on contact elements whereas the Flat-jack and Menard pressuremeter testing is simulated using FE continuous homogeneous nonlinear materials based on a Drucker-Prager (D-P) model. The calibration of the D-P model input parameters is performed through a sensitivity analysis followed by an optimization strategy based on a genetic algorithm. The methodology showed the potential to calibrate the material constitutive parameters to be adopted in FE numerical models of this type of bridge.

Precast reinforced concrete building structures are widely used in the Portuguese industrial stock and throughout Europe. Beam-to-column connections are a key component in this type of structure. However, they are also the source of significant damage, as reported in recent earthquakes. Different configurations are common, such as using a dowel, neoprene or just assuming a concrete-to-concrete interface. Both are characterized by a low deformation and strength capacity, presenting a significant vulnerability against seismic actions. Based on this motivation, a novel low-cost and easy-to-apply retrofit connection is herein proposed to reduce this vulnerability. Shear tests were performed to compare the performance of a retrofitted connection with the as-built configuration (i.e. concrete-neoprene interface). The experimental tests showed a good performance of the proposed retrofit solution, emphasizing the importance of this solution in frictional connections to control horizontal displacements. With the use of this solution, it was possible to overcome the resistance obtained in the connections with dowels in the most vulnerable direction, obtaining a 49% increase in the lateral resistance in the most vulnerable direction (loss of support of the beam on the column) concerning that which was verified in the friction-only connection.

This article presents the validation of a non-linear FE numerical model of a multi-span stone arch railway bridge based on experimental tests and under in-service freight trains. Static loading tests allow evaluating the bridge response in terms of vertical displacements in the arches, opening/closure deformations on specific block joints of the arches, and vertical compressive stress variations in the piers. The bridge FE model is developed by combining the potentialities of a global continuous homogeneous model, based on FEM and Drucker-Prager model, and a local modelling approach based on a dedicated non-linear contact model. The freight vehicle modelling is based on a flexible FE approach, and the validation of the dynamic behaviour of the train-bridge system involved the comparison between numerical and experimental responses. All the numerical responses are in very good agreement with the experimental responses. Finally, a simulation of the dynamic behaviour of the train-bridge system is performed for realistic scenarios of freight traffic considering speeds between 40 and 140 km/h.

The definition of damage states for structural and non-structural elements is necessary to support the seismic vulnerability analyses and identify the most vulnerable elements that need to be retrofitted. The studies on masonry infill walls focused on multiple experimental studies to characterize their in-plane and/or out-of-plane (OOP) behaviour. Some codes have already proposed damage states for masonry infill walls only under in-plane loadings. Also, the study of the normalized energy dissipation and the hysteretic viscous damping when subjected to OOP loadings were not explored. It is recognized that the OOP behaviour of masonry infill walls is still nowadays a topic needing further investigations. This work's main objective is to propose a damage index for infill walls under pure OOP seismic loadings. A detailed analysis of the damage observed in masonry infill walls tested under pure OOP loadings was performed. The damage observed in masonry infill walls made with different masonry units, with and without openings, is carefully detailed. After that, a pilot damage index model is proposed for masonry infill walls made of hollow clay horizontal brick units.

The collapse of the Cypress Street Viaduct during the 1989 Loma Prieta earthquake raised awareness to the seismic design and detailing of the connections between cap beams and columns. Current standards require a considerable amount of transverse reinforcement inside the joints, leading to reinforcement congestion and constructability problems. Moreover, some design rules are rather unclear and the link to the flow of forces in the joint is sometimes lost. However, a clear understanding of the forces flow is essential for the design of new structural systems. This work belongs to a broader research project in which pre-cast solutions of railway viaducts are being developed. Besides the specific requirements of railway bridges, the viaducts shall be able to withstand the seismic excitation of southern Europe. In the solution being considered, the superstructure is bearing-supported and rests on a two-column bent. In order to make it feasible for pre-fabrication and simple assembly on-site, the reinforcement layout at the joint must be optimized without compromising the transmission of forces generated inside the joint during a seismic event. The beam-column joints were designed resorting to strut-and-tie models that enabled the understanding of the force transfer mechanisms within the joints when subjected to the forces from the seismic load combination. The optimized solution was achieved through a superposition of models, which leads to a statically undetermined problem. Detailed 3D nonlinear numerical analyses in the DIANA FEA software are developed to confirm the adequacy of the reinforcement layout. An experimental campaign is being planned to assess the structural performance of the designed solution under cyclic loading.

This paper focuses on the experience of the Rehabilitation Nucleus of the Construction Institute (NR-IC), integrated in the Faculty of Engineering of the University of Porto (FEUP) in the analysis, inspection, and diagnosis of structures with ancient defensive walls existing in Portugal. Aiming at promoting careful and heritage-respecting rehabilitation interventions, in line with the recommendations of ICOMOS (International Council on Monuments and Sites), the NR-IC has participated in several conservation and requalification projects. The development and implementation of a consolidated and holistic methodology of inspection and diagnosis aims to intervene in these historic structures by respecting their authenticity and integrity. In this context, this paper addresses two cases studies in different contexts and state of conservation: the Penedono Castle, in the countryside, and the Peniche Fortress in the sea shore.

The article presents the results of a testing campaign that was carried out to validate the effect of ETICS and seismic plus energy retrofitting techniques on the flexural strength of full-scale masonry brick walls. The study highlights the importance of retrofitting techniques that can improve the energy efficiency and seismic safety of existing buildings, a growing global concern. Based on this motivation, a testing campaign was carried out to validate the effect of ETICS and seismic plus energy retrofitting to improve the flexural strength of full-scale masonry brick walls. For this, nine full-scale specimens were built where three were built without retrofitting, three with ETICS and the remaining three retrofitted with a combined retrofitting technique. Each test involved applying OOP quasi-static uniform load simultaneously at the top and bottom of each wall to reach the collapse. Also, the accuracy of prediction models for non-retrofitted and retrofitted walls will be assessed. The results indicate that retrofitting techniques can significantly improve the flexural strength of masonry brick walls, with combined retrofitting techniques showing promising results for seismic strengthening. The strength and deformation capacity improved high than 200%.

Precast structures are more common in zones not affected by earthquakes or affected by lowto moderate-intensity earthquakes; the application of precast structures in zones of higher seismic intensity is unusual due to the seismic performance uncertainty of these structures.Concerning precast bridges, special attention needs to be paid on the column to cap-beam connections, as well as the methods to anchor the column longitudinal bars into the cap beam or foundation.The constructability of these joints often becomes unworkable due to the high reinforcement concentration that current standards require.Moreover, some design rules are rather unclear and the link to the flow of forces in the joint is sometimes lost.In this paper, to ensure a clear understanding of the forces flow, strut-and-tie concepts were applied to design a column-to-cap-beam joint region of a viaduct located in southern Europe.In addition, different ductility classes were considered.Emphasis was given to nonlinear numerical models developed to validate the strut-and-tie models as well as to evaluate the two ductility scenarios performed.As a modeling strategy, a rotating smeared crack approach was considered; also, constitutive models with fracture energy were considered to simulate the concrete mechanical behavior.Numerical results will be further validated through an experimental campaign planned to assess the structural performance of the designed solution.

The masonry infill walls are often used in the envelopes of reinforced concrete buildings for different purposes, but a large part of them was built before the enforcement of modern seismic and/or energy codes. Due to that, the envelope of the reinforced concrete buildings is responsible for the energy consumption needed for indoor heating and cooling. At the same time, recent earthquakes proved that the infill walls located at the envelope are quite vulnerable under OOP seismic loadings resulting in extensive damage or collapse. The existing standards only provide slight provisions for designing new infill walls and do not combine their energy and seismic performance. Based on that, this research work aims to present a novel holistic performance assessment approach for masonry infill walls. This novel approach aims to classify each wall according to its seismic plus energy performance, allowing to identify which type of retrofitting is needed. A global overview of the international standards concerning the seismic design and assessment of masonry infill walls is performed. Also, the maximum and recommended U-values for external walls indicated by the national code of each European Union country are compared. After that, the new performance assessment methodology is presented and discussed. Finally, a pilot application is performed by carrying out the performance assessment of the infill walls of three buildings (with different numbers of storeys) located in different seismic-climate zones in Portugal. Several types of walls are studied according to their retrofitting type, i.e. non-retrofitted or with independent energy or seismic retrofitting or with combined seismic plus energy retrofitting. It was found that this performance assessment methodology provides important information to support future wall retrofitting. Combined seismic plus energy retrofitting is often needed in the different seismic-climate zones of the Portuguese territory.

For the non-destructive characterization of structures composed of granite stone masonry (heterogeneous materials), in this case of double sheet, one of the most suitable test options is the use of sonic tests. Through these sonic tests, it is possible to estimate the propagation velocities of the P, R and S waves. With these velocity values, it is possible to estimate the elastic parameters that characterize the material. Data acquisition requires special attention because during these tests there are factors that may significantly influence the signal, such as the possible recording of two momentary impacts of the hammer, bad coupling of the recording transducers and environmental noise, which can compromise the quality of the signals, and the literature this topic was not suficciently adressed. It is noteworthy that the estimation of the propagation time of waves and their propagation trajectories are not trivial, since it has great complexity in obtaining the value of the wave's arrival time being its automation a non-strait forward and not reliable process that should be carried out by an experienced user, especially for granite masonries. It is also necessary to identify which types of waves are being measured and represented by these signals, whether P, R or S. However, the identification of waves depends on the intrinsic characteristics of each one of them and on the type of test configuration to be performed. Thus, this work aims to present the advances obtained in the use of sonic tests, considering different configurations, in order to assist in the characterization of structures composed of granite stone masonry. In addition, to proposing new sonic data analysis and processing methodologies to improve the accuracy and reliability of the results obtained in this type of non-destructive test. For this, 8 samples of double sheet granite masonry walls were built in a controlled environment and sonic tests (direct, indirect and unconventional configuration) were performed to characterize these traditional masonries. The results of sonic tests are promising and novel, especially considering that the applicability of these tests on masonry walls is a research area that is not yet sufficiently consolidated, in addition to the difficulties inherent in the fact that the materials are not homogeneous and isotropic. The results showed great variations due to the heterogeneity of the panels. The velocity variation from for the first receiver was higher (1584 m/s) than the other receivers because the first trajectory has less interference from the vertical joints along the wave trajectory. For both tests (direct and indirect), a sensitivity study on the variation of these velocities as a function of the djdT ratio was presented to quantify the estimated velocity for these paths. As expected, the higher this relationship, the lower the velocity values, due to interference from wave attenuation in the horizontal joints. The non-conventional sonic tests proposed in this paper for adequate conditions to obtain the S waves by changing the position and orientation of the receivers and in the direction of impacts (with the aid of an 90 degrees angle fixed to the structure) was adequated demonstrated: it is concluded that the waves interpreted as S reached mean velocity of 1500 m/s, without joint interference. To corroborate the results obtained by the sonic tests, ultrasonic tests were also carried out. The tests confirmed the wave propagation velocity values in the crossblock around 3700 m/s, and with the presence of a joint in the trajectory, the velocities are around 1000 m/ s.

The renovation and refurbishment of existing envelopes of existing RC buildings are usually performed, focusing only on improving their structural or thermal energy characteristics. However, international concern about the sustainability and resilience of existing building structures demands the rethinking of retrofitting techniques that tackle both aspects simultaneously, making the envelopes more energy efficient and seismic safer. Based on this motivation, a testing campaign was carried out to validate the efficiency of novel seismic plus energy retrofitting techniques. Five full-scale specimens were built, three of them with seismic plus energy retrofitting and two of them with solutions developed to improve each case. The five specimens were subjected to pure OOP quasi-static loadings until reached the collapse or partial collapse. The results of the retrofitted walls were compared with a reference specimen (i.e. non-retrofitted) to assess the efficiency of each solution. From the results, it was observed that the novel combined retrofitting can improve the thermal transmittance of the wall by around 70%, and the strength and deformation capacity by up to 125% and 340%, respectively.

The definition of damage states for structural and non-structural elements is necessary to support the seismic vulnerability analyses and identify the most vulnerable elements that need to be retrofitted. The studies related to masonry infill walls focused on multiple experimental studies to characterize their in-plane and/or out-of-plane (OOP) behaviour. Some codes have already proposed damage states for masonry infill walls only under in-plane loadings. Also, the study of the normalized energy dissipation and the hysteretic viscous damping when subjected to OOP loadings were not explored. It is recognized that the OOP behaviour of masonry infill walls is still nowadays a topic needing further investigations. The main objective of this work is to propose damage index for infill walls under to pure OOP seismic loadings. For that, a detailed analysis of the damage observed in masonry infill walls tested under pure OOP loadings was performed. The damage observed in masonry infill walls made with different masonry units, with and without openings, is carefully detailed. After that, a pilot damage index model is proposed for masonry infill walls made of hollow clay horizontal brick units. The third objective of this work was the assessment and discussion of their normalized energy dissipation capacity and their hysteretic viscous damping. Some analytical formulations were proposed to estimate these parameters. A database containing thirteen OOP tests performed by three different authors was used to achieve these goals.

Seismic hazard assessment in several sites worldwide depends on two or more seismic sources. Many countries affected by subduction zones have strong motions earthquakes originated in at least two important seismic sources. In Mexico, interplate earthquakes (subduction process) have epicenters located in the Pacific coast with hypocenter depths less than 45 km and intraplate earthquakes (intermediate-depth earthquakes) normally have epicenters inside the continent with depth hypocenters greater than 45 km. Both seismic sources can potentially produce events with magnitudes Mw greater than 8.0 and, therefore, generate severe damage to the country's infrastructure. The design process of the bridges in Mexico is based on the chapter of Seismic Design of the Manual of Civil Structures of the Federal Electricity Commission. The standard allows to reduce the spectral ordinates of the design spectra by ductility and overstrength. It establishes an overstrength factor of 1.5 to reduce the design spectra, value not well supported by the Manual. This study evaluates the effect of the seismic source and methodology used to compute overstrength factors of common typologies of reinforced concrete bridges. The seismic capacity of the bridges was calculated with nonlinear static analysis and nonlinear time history analysis. The results showed that the importance of the seismic source on the overstrength factors depends on the seismic location of the bridges and, in general terms, nonlinear static analysis overestimates the bridges overstrength.

The poor out-of-plane behaviour of masonry infill-walls (MIW) in recent earthquakes, resulted in several casualties and economic losses. The main objective of this work is to present an experimental campaign comprised of four out-of-plane tests of full-scale MIW with the main goal to assess the possible effect of the previous damage, workmanship and test setup in the MIW out-of-plane behaviour. From the results, it was observed that the existence of the prior damage reduced the out-of-plane strength and energy dissipation of about 30% and 70%, respectively. The workmanship can introduce variations in the MIW response from 10% to 30%.

In existing Reinforced Concrete (RC) buildings, the out-of-plane (OOP) collapse of masonry infills can be a significant issue for resulting damage and life safety in case of earthquake. Quite recently, research works from the literature have studied possible strengthening strategies to reduce the vulnerability of the infill panels due to OOP loading. Among these techniques, the use of Textile Reinforced Mortars (TRM) as an innovative reinforcing plater has rapidly become very popular, due to its good compromise between costs of intervention and effectiveness, along with its durability properties. Nevertheless, still quite few studies exist on this topic to experimentally prove the TRM effectiveness on masonry infills, above all in case of pre-existing in-plane (IP) damage. Even fewer studies in the literature are currently devoted to the prediction of the OOP strength of TRM-strengthened infills, despite the necessity to quantify the beneficial effect of the strengthening solution in a force-based safety check. This work shows the experimental outcomes of four full-scale infilled frames under OOP loading, with or without a TRM-based strengthening technique and with or without previous IP damage. First, a look insight the effect on dynamic properties of the TRM strengthening strategy is reported and commented. Then, the (cyclic) IP and (half-cyclic) OOP pseudo-static testing results are shown and compared to each other to analyze the effect of the IP damage on the OOP response with and without strengthening. Lastly, the very few predictive proposals for OOP strength of TRM-strengthened specimens have been analyzed, based on a dedicated collected database, to lastly provide some suggestions for future design tools for TRM applications on infills.

Aiming at promoting careful and heritage-respecting rehabilitation interventions, in line with the recommendations of ICOMOS (International Council on Monuments and Sites), the Rehabilitation Nucleus of the Construction Institute (NR-IC), integrated in the Faculty of Engineering of the University of Porto (FEUP), has participated in several conservation and requalification projects. The development and implementation of a consolidated and holistic methodology of inspection and diagnosis aims to intervene in these historic structures by respecting their authenticity and integrity. This paper focused on the NR-IC experience in the analysis, inspection, and diagnosis of structures with ancient defensive walls existing in Portugal’s border, while addressing several practical cases in different contexts and state of conservation. These structures have lost their original defense function, assuming nowadays a symbolic character of historical memory. In some cases, these structures were maintained, although in other cases they were abandoned, having reached the present time quite degraded. In this context, this paper focuses on three cases studies: the Cross-border Fortresses on the river Minho (Portugal-Spain border), the Guimarães Castle, cradle of the Portuguese nationality; and the Peniche Fortress representing maritime defensive structures. The wall’s structural system is characterized as well as the distinct inspection and diagnoses approaches recommended for each structure. Particularly, the systematization, recording, and processing of information is described and commented during the inspection phase, taking into account the large size of most of the structures involved.

Currently, the upgrade of existing reinforced concrete (RC) buildings focuses only on energy retrofitting measures due to the current policies promoted in the scope of the European Green Deal. However, the structural deficiencies are not eliminated, leaving the building seriously unsafe despite the investment, particularly in seismic-prone regions. Moreover, the envelopes of existing RC buildings are responsible for their energy efficiency and seismic performance, but these two performance indicators are not usually correlated. They are frequently analyzed independently from each other. Based on this motivation, this research aimed to perform a holistic performance assessment of five different types of masonry infill walls (i.e., two non-strengthened walls, two walls with seismic strengthening, and one wall with energy strengthening). This performance assessment was performed in a three-step procedure: (i) energy performance assessment by analyzing the heat transfer coefficient of each wall type; (ii) seismic performance assessment by analyzing the out-of-plane seismic vulnerability; (iii) cost–benefit performance assessment. Therefore, a global analysis was performed, in which the different performance indicators (structural and energy) were evaluated. In addition, a state-of-the-art review regarding strengthening techniques (independent structural strengthening, independent energy strengthening, and combined structural plus energy strengthening) is provided. From this study, it was observed that the use of the external thermal insulation composite system reduced the heat transfer coefficient by about 77%. However, it reduced the wall strength capacity by about 9%. On the other hand, the use of textile-reinforced mortar improved the strength and deformation capacity by about 50% and 236%, but it did not sufficiently reduce the heat transfer coefficient. There is a need to combine both techniques to simultaneously improve the energy and structural energy performance parameters.