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Reinforcing bars in structural concrete are typically designed to carry axial forces. Nevertheless, due to their bending stiffness, the bars can also carry transverse forces, that are associated with the localized bending mechanism (dowel action) resulting from the relative displacements (or slip) wherever a crack interface or a discontinuity interface (between two concrete parts cast at different times) intercept the bar. Such localized bending induces stress concentrations in both the bars and the concrete. The relative displacement can occur at interfaces either perpendicular to the bar or inclined with respect to its axis. Thanks to steel ductility, the bending stresses in the bars due to dowel action do not impair the sectional capacity at the ultimate limit state. Fatigue verifications, however, require an accurate evaluation of these stresses under imposed transverse displacements or shear forces. As well known, dowel action can be described by means of the traditional unidimensional Winkler's model (beam on an elastic foundation), where the bearing stiffness of the concrete embedment is typically introduced through a couple of parameters, namely the bar diameter and the concrete strength in compression. The actual behavior of a dowel, however, is definitely more complex and for such a reason, improvements are needed for the Winkler's model to introduce other parameters typical of actual structures. Hence, a new formulation is introduced in this study for the bearing stiffness, that is calibrated based on mechanical considerations and measurements with optical fibers. The proposed formulation also accounts for the following parameters: angle between the crack and the bar, concrete‐cover thickness, number of load cycles and the softening effect caused by the local secondary cracks radiating from bar ribs during the pull‐out process. The predictions of the model—implemented with the proposed bearing stiffness—fit fairly well the test results under both monotonic and cyclic loads, in terms of shear force–transverse displacement response and peak stress in the reinforcing bars. [ABSTRACT FROM AUTHOR]

The preservation of the degrading transport infrastructure is vital, as replacing it is impossible in view of limited budgets and environmental impacts. One component in overcoming this challenge is the evaluation of the reliability and the calculation of the remaining service life of existing structures. These structural reliability reassessments allow for the identification and utilization of load‐bearing capacity reserves. The consideration of actual structural characteristics and environmental conditions, various of which can be gathered by means of numerous measurement and inspection techniques, has the potential for more realistic computation results and therefore more economic decisions about the operation as well as maintenance activities. This article attempts to shed light on the potential of nondestructive testing (NDT) methods for updating the input variables in the ultimate limit states during a recalculation. The approach of the NDT‐supported reliability reassessment is demonstrated using a prestressed concrete bridge emphasizing the bending proof in transversal direction. As a result, the semi‐probabilistic, probabilistic and NDT‐based reassessment results are compared and the effects of NDT‐supported structural analysis on the calculated reliability are highlighted. [ABSTRACT FROM AUTHOR]

Structural capacity evaluation is essential to support the safety assessment and decision-making process of existing building structures after disastrous earthquakes. Current post-earthquake evaluation practices rely more on manual on-site inspections, which are labor-intensive and subjective. A simulation-based capacity evaluation could be a desired alternative when numerical models for these buildings are prior-identified and updated using structural health monitoring data. This study proposes a procedure for identifying the capacity curve and assessing the residual capacity of existing structures using seismic monitoring data. The mass-normalized spectral acceleration-displacement (AD format) relation is first defined in a single-degree-of-freedom system. Considering the post-event deterioration of structural capacity, a data-driven reduction factor for the capacity curve is introduced to quantify the potential structural degradation. With the aid of the updated capacity curve, the residual capacity of the earthquake-damaged structure is then predicted via incremental dynamic analysis. The feasibility and accuracy of the proposed method are analyzed via numerical simulations and further validated using a large-scale shaking table test and a real-world instrumented building. Results show that the proposed method could identify the capacity curve of the existing structure from seismic monitoring data and estimate the hysteresis responses with a favorable agreement. It could provide the residual capacity of the target structure and quantify its capacity reduction, which can informatively facilitate the post-earthquake structural safety management. [ABSTRACT FROM AUTHOR]

In typical reinforced concrete design, reinforcement is designed to carry axial forces, but it can also resist transversal forces by dowel action. This is usually neglected for simplicity's sake in the design phase, but it can be accounted for either explicitly in mechanical models or implicitly in empirical relationships. Furthermore, there are cases where the connection between various concrete elements explicitly depends on dowel action, as for example, in connections between precast elements or between two concrete parts cast at different times. On the other side, dowel action can have a negative impact on the fatigue resistance of reinforcing bars subjected to cyclic loading, because of the local stress concentrations near interfaces due to relative movements, either in sliding or in opening of cracks not perpendicular to the bar. For the assessment of the remaining capacity of existing structures, improved models of the behavior are needed, including realistic models of the behavior of concrete, steel and their interfaces. The aim of the present paper is to provide a contribution to a better understanding of dowel action by two test series. The first series focused on the behavior of the dowel: the concrete specimens with the embedded bars were placed in a custom‐made test setup and subjected to monotonic or low stress‐level cyclic actions with a longitudinal and a transversal crack opening component, up to developing the full plastic capacity of the dowel and rupture at the peak of catenary action. The measurement system included tracking the displacement field at the surface of the concrete and the strains in the dowel by optical fibers glued on its surface. The latter measurements allow to derive the internal forces in the reinforcing bar and deformed shape of the bar as well as the contact pressure between the bar and the surrounding concrete. The results show a strong dependency on the test variables: diameter of the bar, imposed crack kinematics and angle between the bar and the crack. The second test series looked more closely at the behavior of concrete underneath the bar, in the presence of a point load introduced at various locations into concrete through a reinforcing bar. A comparison of the test results with existing models shows a general good agreement and some aspects that deserve to be improved. [ABSTRACT FROM AUTHOR]

In the evaluation of existing bridges and viaducts, relying solely on a desk study is often inadequate for determining their structural reliability. Performing a proof load test provides valuable field data that offers detailed information about the structural integrity. However, the relation between the magnitude of the load and the structural reliability is not immediately clear. This study addresses the challenges associated with determining the target load and highlights the uncertainties that play a key role. A case study is presented that shows the time-dependent character of the structural reliability and the influence of an informative and a weakly informative prior distribution in a Bayesian context. It is shown how both past traffic loads and a proof load test may contribute to the proven strength of a structure. The described method provides a starting point towards a flexible approach for proof load testing in which structure-specific knowledge levels and requirements are considered. [ABSTRACT FROM AUTHOR]

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Concrete confinement using fiber-reinforced polymers (FRPs) has been vastly used for strengthening of reinforced concrete (RC) columns. The strengthening of RC columns belongs to the realm of existing structures, which has been recognized as distinct from the design of new structures. Code development efforts for the strengthening of RC columns should follow a reliability-based framework similar to the one used in the code development for new structures. In this process, a number of additional issues arise: the mechanical model of FRP confinement representing existing RC columns, the statistical description of the design variables, and the target reliability to be attained. In this study, the reliability levels of 288 axially loaded, FRP-RC short columns of circular cross sections, strengthened according to ACI 440 guidelines, are assessed. Monte Carlo simulation is used in the probabilistic description of column strength and computation of the probability of failure. An FRP confinement model that explicitly accounts for the presence of transversal steel and attendant model errors associated to the estimation of ultimate stress and ultimate strain are used in the computation of the FRP-RC column capacity. The values of the reliability index are in the range of 3.92 to 4.61, satisfying the target reliability suggested for both new and existing structures. The research findings presented herein provide further support for the efforts of ACI Committee 440 in the development of standards related to the FRP strengthening of RC columns. [ABSTRACT FROM AUTHOR]

Retrofitting measures for crane runway girders for service life extension For moving goods overhead most industrial companies use bridge cranes which are mostly moved on crane runways. Due to the movement of the bridge crane and the hoisting of loads the crane runway girder and its supporting structures are subjected to cyclic loading. Therefore a verification against fatigue is needed. After expiry of the calculated service life individual and costly concepts are needed for a safe continued use of the crane runway. In the course of the research project NE‐Industriebau the University of Applied Sciences Munich investigated multiple retrofitting and strengthening methods for pre‐damaged existing crane runway girders to effectively and safely extend the service life. Therefore fatigue tests on constructional details that are typical for crane runways were performed with different stages of pre‐damage and strengthening methods i. e. hammer peening, grinding and steel cover plate reinforcements with different application techniques. In this article common measures for a fatigue‐proof strengthening of existing crane runway girders and the previous results of the research project are summarized. [ABSTRACT FROM AUTHOR]

Potentials of direct material testing on existing structures – Strength reserves of a prestressed concrete viaduct Recurring questions regarding the selection of appropriate populations in the context of material testing for reinforced and prestressed concrete bridge, as well as the strength reserves of existing concrete, were investigated through a special case study of a prestressed concrete viaduct with in‐section construction on formwork carriage. In this scope, 141 drill cores were taken from Unterrieden Viaduct, which is to be dismantled, and tested for either compressive strength, splitting tensile strength or Young's modulus. The data sets were statistically analyzed. The results impressively demonstrate the potential of the direct determination of material parameters on existing structures. In particular, the anticipated compressive strength values were surpassed by 40 %, and the characteristic values from material testing even exceed the assumptions based on as built documents by over 100 %. Furthermore, an investigation of potential populations on the superstructure is carried out in order to develop recommendations for future sampling. For this purpose, the sample taken is divided into different potential populations and statistically analyzed. The result shows a very uniform structure with a dispersion well below the normative assumptions. This hardly provides any arguments for subdividing the superstructure into different populations. [ABSTRACT FROM AUTHOR]

The European railway network includes many steel truss girder bridges, often dating back to the end of the nineteenth century. Assessment by the partial factor method according to Eurocodes often reveals insufficient reliability of these bridges. In particular, they fail to satisfy the equilibrium limit state when a strong wind occurs simultaneously with an unloaded train crossing the bridge. To avoid unnecessary structural interventions and expensive traffic restrictions, representative types of these bridges are tested in a wind tunnel to refine the force coefficients of wind pressure for the specific shape of the bridge and selected types of lightweight train. The values of force coefficients based on wind tunnel tests correspond to 70–80% of those provided in EN 1991–1–4. Traffic flow records for the railway line under consideration are then utilised to obtain distributions of weights and heights of lightweight trains. Detailed probabilistic analysis focused on a long-span truss bridge with an intermediate bridge deck demonstrates that the reliability of this bridge is close to the target reliability level when wind tunnel force coefficients are considered along with site-specific free-field wind and railway traffic records. [ABSTRACT FROM AUTHOR]

Assessment and evaluation of the structural condition and structural repair of the Norderelbe railway bridge The structural condition of the centennial Norderelbe railway bridge in Hamburg and the structural safety have been assessed and evaluated. Various non‐destructive inspection methods and extensive structural monitoring measures have been applied to aid the structural evaluation and recalculation, revealing some isolated structural deficits of selected members. The contribution describes the steps towards a safe operation of the structure until the prospective commissioning of a replacement bridge which imply the mentioned inspection and monitoring measures as well as structural repairs and the establishment of a continuous structural monitoring. The extensive structural monitoring revealed insights into the structural behaviour of the tied‐arch bridge which are outlined as well. [ABSTRACT FROM AUTHOR]

The vast majority of existing structures in Croatia, as well as in other European countries, are made of unreinforced masonry. The seemingly ideal building material presents a great challenge for engineers in earthquake-prone zones. Given that structural failure can have significant consequences in terms of loss of human lives as well as financial losses, a comprehensive structural reliability assessment is needed. Old existing masonry structures often do not have design documentation, and even when they do, the initial mechanical properties have almost certainly degraded over time. That is why in situ testing is of great importance, but masonry is also characterized by a large scattering of results. After recent severe earthquakes in Croatia, more than ever, there is a need for a more reliable assessment of existing masonry structures. This paper presents reliability approaches for resistance evaluation of existing masonry in a real case study where basic failure modes of the masonry were observed. First, the data recommended in standards were used, followed by the updated data obtained from the flat-jack test. Finally, the design value method (DVM) and the adjusted partial factor method (APFM) were used. These methods align with Eurocode standards for new structures but are also adaptable for the assessment of existing structures. Differences in the results between the existing and the new version of the standard were observed, as well as an increase in the obtained resistances with an increase in the complexity of the methods used. Also, the influence of in situ testing proved to be an important factor in the analysis. [ABSTRACT FROM AUTHOR]

Rocket NG is a startup with experts in civil engineering, electronics, and network engineering. We offer and operate a self‐developed end‐to‐end IoT system for condition monitoring, condition assessment and predictive maintenance. The system is reliable and ease to apply. In this paper the autonomous monitoring system is discussed regarding security, reliability, ease of use and artificial intelligence on the edge (smart algorithms used on the nodes). Additionally, the importance of an easy installation and an intuitive data representation are on discussion. Five applications will be presented. The first application is a crack monitoring on a cantilever bridge. There, different data acquisition modes will be shown for the assessment of static loads, dynamic loads and temperature induced displacements. The second application shows the crack width opening due to heavy transport. The third application addresses the wetting and drying of chloride contaminated water in a concrete wall beside a motorway. The fourth is a monitoring of a passive cathodic protection system. Finally, a digitalization of an analog legacy Extensometer is shown. [ABSTRACT FROM AUTHOR]

Bridges and tunnels are critical elements of the transport infrastructures network as they have often reached their design service life and are subject to unforeseen effects due to accidental actions, climate change or degradation processes. A thorough assessment process of the existing structures, aimed to support a preventive maintenance approach, is crucial at both European and national level. The assessment of existing concrete structures differs from the design of new assets, as the resisting models given are no longer valid with ongoing deterioration mechanisms. It is recommended to formulate the limit states considering the suspected damage mechanisms, with respect to adjusted target reliability levels in verifications. Existing assets also benefits from the availability of information related to the structural condition and the action effect on structures. As such, the EU Commission opened in 2019 the CSA call "Monitoring and safety of transport infrastructure", granted to the IM‐SAFE project consortium and addressed in this paper, which specifically focuses on the proposal for further amendments to the existing EU standards on reliability assessment considering inspections, monitoring and testing and a new standard for preventive maintenance of transport infrastructure. [ABSTRACT FROM AUTHOR]

In recent years, increased effort has focused on developing traffic load models for the safety verification of existing road bridges. In Switzerland for example, this was achieved by updating the alpha reduction factors in the Traffic Load Model 1 (LM1) for new bridges (analogous to the Eurocode LM1 alpha factors), providing a practica approach. The enveloping of the maximum simulated alpha factors, which were calculated by applying measured vehicles to different traffic scenarios, spans and bridge cross‐section types, resulted in the updated LM1 in the SIA 269/1 Standard for Existing Structures. The model development considered spans in the range of 10‐80 m and applied dynamic amplifications as a function of the gross vehicle weight. One limitation of the current updated LM1 is that, as a very high proportion of existing road bridges have spans of less than 15 m, the load effects in this short‐span range tend to be overly conservative. This paper studies the load effect behaviour in the longitudinal and transverse directions, based on actual traffic from Weigh‐in‐Motion (WIM) data. The study utilises all WIM data recorded in Switzerland over the last 10 years. Results from three new short‐span load models are presented which, together, envelope the extreme load effects. A parametric study is presented which highlights some conservatism in the existing code load models. Finally, a case study project is presented, in which these updated models were used to verify the structural safety of a historic road bridge. [ABSTRACT FROM AUTHOR]

The infrastructure of ASFiNAG is mainly built from reinforced and prestressed concrete, which despite all regular maintenance measures, is subject to ageing and degradation. The major degradation process is chloride attack, followed by carbonation, which both lead to corrosion of the reinforcing steel. A new method, which represents a significant improvement on previous assessments, is used in this paper to analyze chlorides in concrete. The paper also introduces a new concept for the durability assessment by using objective indicators, like chloride content, electrical resistivity, and corrosion potential. For objectivity and a reliable determination of the condition state, an overall performance index derived from the condition indices using an analytic hierarchy process (AHP) is adapted. The model is applied to excellent and dense data from a monitoring system and investigations taken from reinforced concrete components beside a motorway. [ABSTRACT FROM AUTHOR]

The progressive increase in loads and frequency of trains traversing over aging railway infrastructure can lead to large lateral forces and displacements that could potentially cause derailment and problems related to safety. Reliance only on design thresholds for safety assessment of existing bridges can lead to conservative evaluations, unnecessary replacements, and increased maintenance costs. However, there is a lack of data on lateral behavior of existing railroad infrastructure. This article examines the recommended lateral load and displacement specified in codes. It specifically analyzes the responses of railroad bridges under revenue service traffic, using field-collected data. The goal is to establish a contextual understanding of how modeling, field data, and the code relate to each other. First, this paper presents an investigation of measured lateral forces of existing railroad bridges using different instrumentation techniques such as truck performance detector, track loading vehicle, and linear variable differential transducers (LVDTs). Second, a series of lateral displacement field monitoring data of three railroad steel bridges using the LVDT and the time history analysis of two railroad timber bridges under train load events with different speed and axle load using laser are presented. Time history responses of railroad bridges under train load provide an objective qualification to evaluate their current condition. Finally, the data help to identify maximum lateral displacement, train speed, symmetry of bridge response associated with the construction, the number of cars, and freight versus passenger different responses. These measurements are recommended to be used for field evaluations of bridge lateral responses under traffic. This study focuses on lateral load and displacement in railroad bridges. The authors suggest using field monitoring data to ensure the safe operation of existing railroad bridges, because the design code's conservative values may not be sufficient. To assess lateral load, the authors recommend using a pair of forces rather than a single concentrated lateral force. For lateral displacement assessment, the authors suggest the use of a field monitoring technique with LVDT or sensors. This approach enables the creation of a displacement time history that includes train speed and symmetrical movement data. The practical application of this method may be limited by budget, bridge access under revenue service traffic, and safety restrictions for sensor location. Additionally, the amount of data that can be collected depends on the number and location of sensors. Sensor placement must be guided by prior engineering knowledge of the bridge. Finally, data collection may be time-consuming, which may be cost-ineffective and render the whole exercise difficult. In summary, this study proposes a field monitoring approach for lateral load and displacement assessment that requires a careful consideration of practical limitations. [ABSTRACT FROM AUTHOR]

Steel structures are second most numerous in the stock of existing buildings. In contrast to dominating concrete buildings, they are typically lightweight and are more sensitive to alterations in use or loads. While the sustainability principles require to maintain and keep using these structures, structural assessments often indicate insufficient reliability and need for replacements. The submitted contribution shows that the most important reliability considerations affecting the sustainability of existing steel structures consist of specifying (1) appropriate target reliability level, (2) verification methods, and (3) intervention procedures. The study focuses on the first two aspects. (1) Optimum target reliability can be specified by probabilistic optimisation considering sustainability aspects including structural costs, and expected consequences of replacement and of possible failure. It is shown that lower reliability levels might be considered for the assessment of existing structures than for the design of new structures, with benefits for sustainability in construction. Regarding (2), the most efficient verification methods are based on advanced probabilistic approaches. It is demonstrated that sustainability may be significantly affected by the selection of assessment methods. Advanced reliability approaches commonly reduce assessment requirements by 10–15 %. Sustainability indicators are mostly related to the key aspects (1) and (2). Using the advanced methods may bring a significantly positive contribution to sustainability, particularly when an upgrade of the existing structure is associated with high economic cost and significant environmental impact.

Both when designing new and when evaluating existing structures, methods of analysis must be based on established engineering theory and practice. Also, the general principles of structural reliability regarding the treatment of uncertainties when verifying the established requirements apply to both, design and assessment. Taking further into account that new or existing civil engineering works are usually unique, either because they are prototypes or because they are exposed to specific conditions, from an engineering point of view, structural analysis and verification must be carried out, both in the design and in the assessment, under case-specific conditions according to the same principles. However, important differences exist between assessment and design, for example regarding the state of information and its updating through different types of information, the structural condition, reliability requirements, verification methods or decision options. Such differences, which are briefly summarized in the contribution, can often lead to a high level of conservatism when using design-oriented methods for assessment purposes. There is therefore a need to develop a generally recognized, coherent and harmonized set of rules for the assessment of existing structures. The CEN Technical Specification for assessment and retrofitting partially closes this gap, but only establishes principles on assessmentspecific reliability aspects. The consistent application of these generic assessment rules in practice requires further assumptions, or even case-specific developments. Practical applications are therefore of paramount importance in identifying relevant issues to consider in the future development of assessment methods and codes.

The Bangkok MRT Orange Line East Project consists of 6 km long twin tunnels and seven stations. The tunnel alignment runs along one of the most congested road corridors of the city. Due to adverse conditions of limited road right of way, obstructions from existing structures such as buildings, infrastructure, tunnels, and other utilities, the design and construction of the tunnel require careful consideration and implementation of excavation works to limit excessive ground movements and mitigate the potential impacts on existing structures. This article presents the concepts and procedures in detail on assessing the impact on each type of adjacent structure due to tunnel construction which contribute to the successful completion of the MRT Orange Line Project. Additionally, some mitigation measures for critical cases are highlighted. [ABSTRACT FROM AUTHOR]

Digitalization of waterway infrastructure – from maintenance of existing structures to ideas of new constructions The planning of new construction, renovation, expansion and repair of traffic water structures almost always involves very old structures. In the context of digitization and infraBIM, as‐built models are an important starting point. A structure information model, which is often to be considered in a holistic sectional view of waterways with partial models, serves as the basis for further maintenance and new construction planning. BIM planning, which is still relatively untested in hydraulic engineering compared to building engineering and bridge construction, faces the challenge of predominantly unique structures. In addition, the interfaces between civil engineering structures and integrated mechanical engineering represent important areas of integral planning. The article provides an overview of the various digitalization approaches in structural hydraulic engineering based on practical examples and focuses on special features and best practices. [ABSTRACT FROM AUTHOR]

The acquisition and appropriate processing of relevant information about the considered system remains a major challenge in assessment of existing structures. Both the values and the validity of computed results such as failure probabilities essentially depend on the quantity and quality of the incorporated knowledge. One source of information are onsite measurements of structural or material characteristics to be modeled as basic variables in reliability assessment. The explicit use of (quantitative) measurement results in assessment requires the quantification of the quality of the measured information, i.e., the uncertainty associated with the information acquisition and processing. This uncertainty can be referred to as measurement uncertainty. Another crucial aspect is to ensure the comparability of the measurement results.This contribution attempts to outline the necessity and the advantages of measurement uncertainty calculations in modeling of measurement data-based random variables to be included in reliability assessment. It is shown, how measured data representing time-invariant characteristics, in this case non-destructively measured inner geometrical dimensions, can be transferred into measurement results that are both comparable and quality-evaluated. The calculations are based on the rules provided in the guide to the expression of uncertainty in measurement (GUM). The GUM-framework is internationally accepted in metrology and can serve as starting point for the appropriate processing of measured data to be used in assessment. In conclusion, the effects of incorporating the non-destructively measured data into reliability analysis are presented using a prestressed concrete bridge as case-study.

Assessment of the influence of human activities on recent, current, and future global and regional climate conditions and extremes has advanced sufficiently to provide a reasonable measure of its impact across the globe. The lack of concurrent adaptation of the design base for load bearing structures results mainly from the absence of a clear signal that climate change will have a significant effect on the climate actions that are accounted for in the structural design basis. The recent IPCC assessment of the physical science basis of climate change reports significant advances in observing and projecting changes in weather and climate extremes due to human influences. This provides an opportunity to reassess projections of future climate action conditions. Whilst the IPCC assessment confirms previous indications that, for example extreme wind will respond moderately globally, improvements in understanding and projecting changes show that trends will be overshadowed by uncertainties. The implication is that the design base will need to account for increasing uncertainties as climate actions are projected into the future, over the service life of existing structures, as well as those designed to current standards. The design base consequently in advance need to reflect continuous changes of existing structures.

Two test series were examined using nondestructive measuring methods by six independent laboratories before determining their compressive strength. The nondestructive test methods used were the rebound hammer and ultrasonic pulse velocity measurement. Two types of geometries were investigated: drilled cores and cubes. The measurement procedure for each of these datasets is conditioned to the geometry and is therefore different.The first series consists of 20 drilled cores (approximately diameter/height = 10 cm/20 cm) from the 55-year-old Lahntal Viaduct near Limburg, Germany. After preparation in the first laboratory, the lateral surface of the drilled cores was tested with the rebound hammer using a given pattern. Every laboratory tested every drilled core at different locations. Ultrasonic measurements in transmission were performed repeatedly at predefined points on the flat surfaces of the specimen.The second series consisted of 25 newly manufactured concrete cubes of a mix with a target concrete strength class of C30/37. The edge length was 15 cm. Each laboratory received five specimens of this test series. Thus, contrary to the first series, each specimen was tested by only one laboratory. Two side faces of each cube were tested with the rebound hammer. In addition, ultrasonic measurements were performed by one laboratory. The time of flight was measured between the tested side faces of the rebound hammer at different positions.For both series, rebound hammers were used to determine the R-value as well as the Q-value. The rebound hammer models within the laboratories were always the same, while they differed between the laboratories. The ultrasonic measurements took place with different measurement systems and couplants. Finally, both specimen series were tested destructively for compressive strength.The dataset contains the raw data summarized in tabular form. In addition, relevant calculated data are included in some cases. For the ultrasonic measurements, the time of flight has already been converted into the ultrasonic velocity. Besides, in addition to the raw data of the compressive strength test (force, weight, and geometry values), the calculated compressive strengths and densities are also provided.

The safety assessment of existing structures in areas with a relevant seismic hazard is one of the major topics for engineers since many existing reinforced concrete structures have been realized disregarding seismic design with minimal details with respect to present practice. In this context, seismic assessment is a primary issue in order to identify the best retrofitting solution with the aim of enhancing the efficiency of existing buildings. In recent years, with the aim to enhance the seismic behavior of reinforced concrete (RC) structures (with particular care to existing ones), the system of seismic isolation adopting friction pendulum (FPS) devices proved to be among the most diffuse and effective solutions. The purpose of this paper is to explore the effectiveness of the refurbishment using FPS with single concavity devices on the performance of one irregular existing RC building placed in a highly seismic area of central Italy. First, the geometric and material characteristics of the building have been determined within the approach based on the "knowledge levels". Second, a suitable numerical model based on a fiber-modeling approach has been established using SAP2000, including relevant mechanical non-linearities. Then, a set of 21 natural seismic inputs, inclusive of 3 accelerations over vertical and horizontal directions, was adopted with the aim of performing non-linear (NL) dynamic simulations. The NL dynamic simulations have been performed considering the structural system, both inclusive and not inclusive of the FPS isolator devices. The influence of the actual distribution of infill masonry panels on the overall behavior of the structure has also been evaluated in both of the cases mentioned above. Finally, the outcomes deriving from the NL dynamic simulations were helpful in assessing the advantages of the intervention of retrofitting to improve the seismic performance of the building, highlighting the influence of masonry infills. [ABSTRACT FROM AUTHOR]

Current post-earthquake assessment relies on manual inspections to assess the safety conditions of existing buildings. Such field inspection in a building-to-building manner remains challenging as it is labor-intensive and relatively inefficient, which may affect the associated post-earthquake management plan and the economic loss. A simulation-based rapid performance evaluation of buildings is, therefore, needed. This study proposes a seismic performance evaluation framework for the frame structures with the aid of local ground-motion measurements, prior-event field testing, and time-history analysis. The linear behavior of the SDOF model is calibrated by the dynamic properties determined from dynamic tests under ambient vibration. When an earthquake happens, the peak spectral displacement of the building is estimated using the calibrated SDOF model via a time-history analysis. The feasibility and accuracy of the proposed method are validated using the data and inspection results collected from the Van Nuys hotel under Whitter, Landers, BigBear, and Northridge earthquakes. Results reveal that the proposed method can estimate the peak displacement with a favorable agreement. The proposed method is further applied to assess the conditions of thirty-five frame structures under earthquakes those happened from January 2019 to April 2022, in Gongxian city, Sichuan province. [ABSTRACT FROM AUTHOR]

In the recent years, Digital Image Correlation (DIC) was applied with very promising results to monitor cracks in reinforced concrete structures. However, current DIC measurements present some limitations to characterize the existing crack (already present in the reference image) and for long-term monitoring due to the principles of the correlation algorithm. This paper presents two techniques to complement DIC in these two cases. The first one is based on direct detection using existing algorithms. The second one is based on the detection of markers fixed around the crack. Their relative position in different images is used to compute the crack displacement that occurred between the inspections. A conventional DIC set-up can be used for this technique. Simplified and refined methods are proposed to quantify the measurement uncertainty and to determine the number and position of markers. Both techniques are validated in laboratory conditions and in-situ in an existing concrete bridge. The combination of the two presented techniques with conventional DIC is promising and could be of interest for applications with complicated crack patterns where a detailed understanding of the crack kinematics is required. • A direct detection technique is validated to characterize existing cracks in reinforced concrete structures. • A marker-based technique is proposed for long term monitoring of cracks in existing concrete structures. • The techniques are validated in laboratory conditions and in an existing prestressed concrete bridge. • Limits of applicability and recommendations are provided for both techniques based on the performed validation tests. [ABSTRACT FROM AUTHOR]

The vast majority of existing structures in Croatia, as well as in other European countries, are made of unreinforced masonry. The seemingly ideal building material presents a great challenge for engineers in earthquake-prone zones. Given that structural failure can have significant consequences in terms of loss of human lives as well as financial losses, a comprehensive structural reliability assessment is needed. Old existing masonry structures often do not have design documentation, and even when they do, the initial mechanical properties have almost certainly degraded over time. That is why in situ testing is of great importance, but masonry is also characterized by a large scattering of results. After recent severe earthquakes in Croatia, more than ever, there is a need for a more reliable assessment of existing masonry structures. This paper presents reliability approaches for resistance evaluation of existing masonry in a real case study where basic failure modes of the masonry were observed. First, the data recommended in standards were used, followed by the updated data obtained from the flat-jack test. Finally, the design value method (DVM) and the adjusted partial factor method (APFM) were used. These methods align with Eurocode standards for new structures but are also adaptable for the assessment of existing structures. Differences in the results between the existing and the new version of the standard were observed, as well as an increase in the obtained resistances with an increase in the complexity of the methods used. Also, the influence of in situ testing proved to be an important factor in the analysis.