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Development of digital structural maintenance for federal highway engineering structures – Workshop "Digital structural maintenance including structural inspection" in Bonn in February 2024 This report presents the results of the workshop "Digital building maintenance including structural inspection", which took place in February 2024 in Bonn at the Federal Ministry for Digital and Transport. The aim of the event was to highlight market‐ready solutions related to digitalization and their future developments, as well as to formulate requirements for further developments by users. During individual workshop sessions, participants from industry and administration discussed the challenges, potentials, and next steps for implementation on the topics of structural inspection, non‐destructive testing, and monitoring. The results indicated that the field of building maintenance has significant potential for support through digital technologies. This includes, among other things, the adaptation of relevant regulations, the use of best practice applications, the integration of digital technologies into the maintenance process, support in the development of a data management system, and the training of relevant processes and workflows. [ABSTRACT FROM AUTHOR]

The efficiency and reliability work best in renewable energy systems highly dependent on the wellness of the designing of wind turbine blade. Additive manufacturing, namely 3D printing, opens new possibilities for manufacturing scaled models with complex geometries and advanced materials. This paper brings a significant study on the modal and fatigue life analysis of a wind turbine blade using ANSYS software which is 3D printed with the scale of 1:3.75, and further validated in the experimental view. Fabricated out of 0-degree-oriented carbon-fiber-reinforced PLA, the blade is extensively studied for structural integrity and vibrational response. Geometric and dynamic scaling laws are applied to ensure an accurate representation of full-scale blade behavior in scaled models. Modal analysis in ANSYS Workbench elucidates mode shapes and frequencies, while fatigue life analysis assesses structural durability under realistic loading conditions. Experimental testing employs precision instrumentation, validates numerical predictions, and confirms enhancements in structural integrity achieved through design modifications. The findings underscore the efficacy of additive manufacturing and iterative design optimization in advancing wind energy infrastructure, exemplifying a symbiotic fusion of computational modelling and experimental validation. [ABSTRACT FROM AUTHOR]

Hybrid simulation is an innovative method that combines an analysis model of a structural system with physical tests of one or more substructures. The analysis model is typically a finite element analysis (FEA) model that outputs displacements applied to the physical substructure using a control system operated in displacement control. For stiff specimens, the displacement commands can be so small that the control system has difficulty imposing the command displacements accurately. To do hybrid simulation with a stiff specimen, force control is desirable. Cascade control, which features two layers of closed loop control, is proposed to address this issue. The inner control loop has force control mode that provides accurate control for hybrid tests with stiff specimens. The outer control loop is in displacement control mode for accepting displacement commands from an FEA model. The effectiveness of the cascade control method in conducting hybrid simulation of stiff test specimens was evaluated with three sets of tests. For each set of tests, the results of both cascade control and displacement control methods were compared. The three test cases covered a wide range of variation from specimen size, test equipment, model type (2-D vs. 3-D), experimental element type (beam-column vs. truss), and test speed (slowdown 10 times in Test Case 1 and 2 versus 100 times in Test Case 3). In all cases, cascade control proved to be an effective method for conducting hybrid simulation with a stiff specimen. [ABSTRACT FROM AUTHOR]

The current study shows the application of 3D printing methods for structural testing. The primary goal of the experiments was to facilitate mechanical testing using polyamide 6 (Nylon) augmented with glass fibres, or PA6-GF. The assessment aims to demonstrate the efficacy of 3D printing techniques in preparing structural specimens and determining the material’s suitability for mechanical testing. This approach has the potential to optimize the process, save time, and reduce operational costs, including technician time and workload. the PA6-GF was tested to assess stress-strain curves and ultimate capacity before being employed as a construction material in the structural laboratory. Test results had shown a modulus of elasticity for the PA6-GF in the range of 992 MPa and 2040 MPa and a Poisson’s ratio in the range of 0.34–0.40. The application of 3D printing techniques and PA6-GF were successfully applied to overcome the limitation of commercially available stands to support steel meshes for the construction of a bridge deck to a reduced scale of 1–6. The use of PA6-GF material provided adequate mechanical properties and helped in reducing both construction time and cost on the order of 14 % and 7 %, respectively. These results indicates that this technology is a promising tool to enhance both construction processes and construction quality.

Abstract Precast Concrete Sandwich Panel (PCSP) is composed of concrete load-bearing panels, thermal insulation panels, and decorative panels, which are assembled through connectors, integrating load-bearing, thermal insulation, and decorative functions. The connector bears the main shear force between the wall panels, and the shear resistance and insulation performance of the connector largely determine the mechanical stability and insulation effect of the wall panels, which is a key component in PCSPs. The current common practice is to cross assemble stainless steel insulation (SSI) connectors and Glass-Fiber-Reinforced Plastic (GFRP) connectors into PCSPs, which can reduce building energy consumption and save resources while meeting strength and insulation requirements. A large-scale pull-out test on a PCSP with intersecting SSI-GFRP connectors was conducted in this paper. The damage process and damage pattern of PCSP were observed and the shear performance of SSI-GFRP connectors was analyzed. Secondly, a numerical analysis model of the test PCSP was built using ABAQUS finite element software and its validity was verified through the test data. In addition, parameters such as connector diameter, connector number ratio and concrete strength were analyzed for their effect on the shear performance of SSI-GFRP connectors and it was found that connector diameter and connector number ratio had a significant effect. Finally, it is found that there are some differences between the classical theory for calculating the shear performance of SSI-GFRP connectors and the actual results. A theoretical correction factor (ζ) is given to improve the accuracy of the calculation of the classical theory, and its influencing factors and changing rules are investigated.

Standard methods for fire resistance testing require large-scale assemblies and are typically conducted on specialized furnaces at considerable cost. This research focused on developing a scaling methodology for a reduced-scale fire resistance test that reduces the size of the test article while maintaining the same thermal and structural response exhibited in the large-scale test. The developed scaling methodology incorporates uniform geometric scaling, Fourier number time scaling, and furnace boundary condition matching. The scaling laws were experimentally validated with fire exposure tests on gypsum wallboard samples at three scales (full-scale, 1/2-scale, and 1/6-scale). In the tests, samples were exposed to a full-scale equivalent of 60-min of ASTM E119 fire curve exposure on a reduced-scale horizontal furnace, and the temperature rise through the thickness profile was measured. Models were created to calculate the modified fire curves for the smaller-scale tests. Experimental results show that on the exposed surface, the 1/2-scale absolute temperature was within 1.7% of full-scale, while the 1/6-scale temperature was within 2.5%. While the time-dependent properties of burning and cracking caused visual differences in these gypsum tests, modeling and temperature measurements demonstrated that the test results were thermally similar. The good similarity of temperatures is achievable in fire exposure tests of non-combustible gypsum wallboard down to 1/6-scale. [ABSTRACT FROM AUTHOR]

The primary aim of the present study is to explore the use, advantages and potential of two advanced data acquisition techniques – 3D scanning and digital image correlation (DIC), in the testing of metallic structures. 3D scanning is a novel method for capturing the full outer geometry of an object. It is being increasingly used in experimental studies for the determination of dimensional parameters and the characterisation of local and global imperfections, examples of which are given and discussed. Digital image correlation (DIC) is a rapidly evolving technology for the full‐field measurement of the displacements and strains over a surface. A brief introduction to DIC and its workflow is firstly provided. Example applications of DIC in various scales of experiments, including material tests, structural element tests and full‐scale structural system tests, are subsequently discussed. These new‐generation data acquisition techniques enable structural researchers to gain a deeper insight into the behaviour of metallic structures in experimental research. [ABSTRACT FROM AUTHOR]

Summary: Data flow testing creates test requirements as definition‐use (DU) associations, where a definition is a program location that assigns a value to a variable and a use is a location where that value is accessed. Data flow testing is expensive, largely because of the number of test requirements. Luckily, many DU‐associations are redundant in the sense that if one test requirement (e.g. node, edge and DU‐association) is covered, other DU‐associations are guaranteed to also be covered. This relationship is called subsumption. Thus, testers can save resources by only covering DU‐associations that are not subsumed by other testing requirements. Although this has the potential to significantly decrease the cost of data flow testing, there are roadblocks to its application. Finding data flow subsumptions correctly and efficiently has been an elusive goal; the savings provided by data flow subsumptions and the cost to find them need to be assessed; and the fault detection ability of a reduced set of DU‐associations and the advantages of data flow testing over node and edge coverage need to be verified. This paper presents novel solutions to these problems. We present algorithms that correctly find data flow subsumptions and are asymptotically less costly than previous algorithms. We present empirical data that show that data flow subsumption is effective at reducing the number of DU‐associations to be tested and can be found at scale. Furthermore, we found that using reduced DU‐associations decreased the fault detection ability by less than 2%, and data flow testing adds testing value beyond node and edge coverage. [ABSTRACT FROM AUTHOR]

Various methods have been developed to produce deck slabs for steel–concrete composite bridges. Usually, the deck slabs are cast with in situ concrete using a formwork carriage, resulting in construction progress of 15 to 25 m of deck slab per week. A new construction method was developed at the Institute of Structural Engineering (TU Wien), which enables the swift erection of the concrete deck slab. This method employs precast deck slab elements with reinforced concrete cross-beams which span in the transverse direction. With this new construction method, producing up to two deck slab sections of 15–25 m per day becomes possible. Further, the performance of novel reinforcement detailing required for the precast deck slab elements is investigated by structural testing. The experiments consist of eight load-bearing tests on four specimens which represent sections of the element during casting and after completion. The investigated parameters in series 1 are the length and spacing of loops, used for protruding longitudinal bars enclosure. In series 2, the enclosure of the shear reinforcement and the height of the cross beams are varied. The results show that the targeted bending capacity could be reached in all tests with no signs of premature failure due to detailing reasons. Based on the experimental results, the feasibility of the new approach is shown and recommendations for detailing are given. [ABSTRACT FROM AUTHOR]

Over the last two decades, the tidal energy industry has laid the groundwork for creating commercially viable tidal power generation projects to strengthen sustainable energy policies around the world. At the end of 2021, the cumulative installation of tidal stream technology that has been deployed in Europe reached 30.2 MW, where the majority of the installations are by small and medium-sized companies. Due to a growing demand among investors related to the global tidal energy industry, the reliability and safety of operational-stage tidal energy systems' components are becoming increasingly important. In this context, companies, universities and research institutes are focusing on conducting large- and small-scale tests of tidal turbine elements to validate their projected design life, and major attention is being given to assessing the structural integrity of turbine blades. This review paper focuses on structural tests that have been reported for axial flow tidal turbine blades manufactured using composite materials around the world, highlighting the testing standards, equipment and instrumentation required. Overall, this review article discusses the state of the art in the structural testing of tidal turbine blades. In addition, it highlights the global concerns and research gaps to ensure the long-term sustainability of axial flow tidal turbine blades. In addition, the information contained in this article will be useful for formulating a smooth and reliable mechanism to enhance the evaluation process of the structural properties of tidal turbine blades in the future. [ABSTRACT FROM AUTHOR]

The construction of market power regulation is one of the critical elements of the current market construction and supervision system construction in China. Firstly， this paper summarizes the detection methods， mitigation measures， and evaluation indicators of overseas electricity market power and compares and analyzes the advantages and disadvantages of structural processes and behavior-influence methods. Then， the problems and challenges faced by China are summarized from the perspective of power supply distribution， power supply mix， network frame power flow， and bidding strategy. The paper analyzes the problems and challenges faced by China’s market power control construction. Furthermore， it points out that China’s market power regulation on the power generation side should take power plants as the primary control object. A regulation system that combines events before and after with emphasis on the behavior-influence method is established. Finally， from the market design and construction perspective， measures to mitigate market power are proposed， and an evaluation index system for market power is given to provide a reference for the construction of market power regulation in China.

Wood has been used in construction has for several millennia; however, global warming has created situations in which the wood needs to be utilized in a more eco-friendly, sustainable, and cost-effective manner. Using wood from trees farmed on wastewater is an ideal option that has been found to be sound for this use. Casuarina glauca wood has been farmed on wastewater for years, making it eco-friendly and cost effective, in addition to being of relatively high strength when compared to soft woods. Hence, within this research, Casuarina glauca wood is used within a hybrid wood-soil system. A scaled model of the structure was constructed and tested structurally until failure in two horizontal planes: the lateral and transverse. The points of weakness in the connections were identified in order to adjust the design, which mainly involved the nails connecting the studs to the upper and lower beams. The adjusted model was constructed including additional X-braces and tested structurally, and was proven to have sufficient strength compared to the wind loads according to the Egyptian Code of Loading. The design was compared to its reinforced concrete alternative to assess its cost-effectiveness and eco-friendliness in terms of the cost per unit area and the carbon emissions per unit area. The system proved to be more cost-effective and eco-friendly when compared to its reinforced concrete counterpart. [ABSTRACT FROM AUTHOR]

Shape-shifting between multiple stable deformation states offers attractive pathways to design adaptive structures. Ideas have been conceptualised in diverse fields, including soft robotics and aerospace engineering. The success of shape-shifting relies on overcoming the energy barrier separating adjacent stable configurations, which necessitates efficient actuation strategies. Recently, multistable mechanical metamaterials have been designed with shape-shifting controlled by an actuator at the local scale, i.e with embedded actuation. This local, embedded actuation creates challenges for quantifying the energy barriers required for shape-shifting. Specifically, the local actuation requires a pair of forces with opposite directions and the direction of the forces must remain constant throughout the entire loading process. Moreover, the loading points must move freely in a direction perpendicular to the loading direction. We present a novel bi-axial test rig for a typical multi-stable lattice metamaterial that accurately determines the energy barrier between stable states by using an embedded actuator and inducing shape-shifting. Our experimental design features two independent actuation systems operating at different length scales: a primary one for a globally applied axial compression of the metamaterial, and a secondary local system for triggering shape-shifting between different stable configurations. Experimental data obtained using this bespoke test rig unveil the metamaterial's response to local, embedded actuation. Excellent agreement with finite element simulations is observed, demonstrating the effectiveness of the test setup in providing measurements of the energy barrier. This work provides a valuable benchmark for measuring energy barriers in multi-stable metamaterials and paves the way for rigorous validation and verification of novel functional metamaterial and structures that leverage shape-shifting mechanisms. • Developed bi-axial rig to quantify energy barriers in shape-shifting metamaterials. • Test rig combines independent local micro & global macro actuation. • Energy barriers between two distinct stable post-buckling modes are measured. • Experimental and numerical results show excellent correlations. [ABSTRACT FROM AUTHOR]

Software testing is the most crucial stage in the software development process. Structural testing, functional testing and models that even support hybrid testing are different software testing techniques. Basic path testing, the most significant structural testing approach, is focused on evaluating software source code. The method emphasizes developing test data inputs to produce all feasible and efficient test paths that connect to all nodes and edges of the graph. The objective is to define the number of independent paths that can define the number of test cases needed to maximize test coverage. It ensured the execution of every statement and condition at least once. A nature-inspired Smell Detection Agent (SDA) algorithm is proposed in this paper to select all paths and prioritize the feasible solution. This algorithm is an optimization algorithm suitable for identifying optimal paths with priority. The concept is derived from the natural behaviour of canines that identified optimal path from source to the destination. The SDA algorithm is based on the evaporation of smell molecules in the form of gas and the perception capability of a smelling agent. The number of linearly independent paths through a programme module is measured by creating a Control Flow Graph of the code, which measures cyclomatic complexity. SDA algorithm gives significant increases in performance while considering the cyclomatic complexity. Complexity analysis of SDA trends to be in the O(E+V log V), while the competitor algorithms have an exponential growth of O(n 2 ). Various experiments were also carried out to emphasis the relevance of the proposed method. Ten different benchmarked applications has been taken for experimental analysis and it was observed to have an increased path coverage of 8% when SDA was used over the traditional methods. Also, the time complexity was reduced by 22%, which shows the powerfulness of the proposed SDA algorithm. [ABSTRACT FROM AUTHOR]

This paper presents an overview of the developments performed at the European Laboratory for Structural Assessment (ELSA) of the Joint Research Centre of European Commission concerning the new generation of servo-hydraulic real-time digital controller/acquisition system adopted in large scale experiments. The hardware architecture is based on EtherCAT® modules that guarantee a versatile and modular system easily adaptable to changing requirements (a typical situation experienced at ELSA with custom adapted non-standardized large scale structural experiments). Other fundamental features of this system are that all the analog signals are digitalized in the proximity of the transducers reducing noise-to-signal ratio (a great advantage for Pseudo-dynamic tests but in general for all experimentation), and all the different slave controllers communicate at each time sampling through a deterministic robust digital bus. In addition to the increasing computer performances, the developed simplified software architecture does offer a substantial improvement of control quality in terms of speed, safety, and accuracy compared with conventional/commercial systems. [ABSTRACT FROM AUTHOR]

Model transformation testing has become crucial as model‐driven engineering has raised the abstraction level for developing software systems. Transformation is written to transform models from one level of abstraction to another, for example, model to model or model to code. A major challenge in testing the transformation is the creation of test models, such that (i) they conform to the source meta‐model (i.e., multiplicities and Object Constraint Language [OCL] constraints on meta‐model) and (ii) they provide coverage of the complete transformation (solving branch conditions for traversing all paths). Manual creation of test models requires a lot of time and effort. Still, the validity of the developed test models cannot be ensured. This paper aims to solve the above challenges using an automated search‐based strategy. The proposed approach is two‐stepped. First, valid test models are generated by solving source meta‐model constraints. Second, the generated models are evolved for achieving the structural coverage of the transformation by solving the branch conditions. A toolset model transformation testing environment (MOTTER) is developed to automate the search‐based solution. The proposed work is empirically evaluated on two case studies using four search algorithms. The result reflects that it successfully generates valid test models for achieving desired structural coverage with high performance on both the case studies. [ABSTRACT FROM AUTHOR]

In life service, the wind turbine blades are subjected to compound loading: torsion, bending, and traction, all these resulting in the occurrence of normal and tangential stresses. At some points, the equivalent stresses, due to overlapping effects provided by normal and shear stresses, can have high values, close to those for which the structure can reach to the failure point. If the effects of erosion and clashes with foreign bodies are added, the structure of the blade may lose its integrity. Considering both the complex shape of the blade and internal structure used, the mechanical behavior of the blade, such as the rigidity and resistance along the length of the blade, are usually determined with some uncertainty. This paper presents the results obtained in the non-destructive tests at static torsion of a scalable wind turbine blade. The objective of the paper was to determine the variation of the equivalent stress in the most stressed points of the blade, in relation to the torques applied. To determine the points with the highest stress, a finite element analysis was performed on the scalable wind turbine blade. Electrotensiometric transducers were mounted at different points of the blade, determining the main stresses in the respective points, as well as their variation during the torsion test, by subsequent calculations. The determinations were performed by applying the torque in both senses, in relation to the blade axis, thus concluding the values of the equivalent stress in the two cases. [ABSTRACT FROM AUTHOR]

Rainwater may penetrate through the cladding, enter the wall assembly, and cause damage to the façade components and interior finishes, which are moisture sensitive, most of the time. In the current paper, the performance assessment of a skylight with a full-scale mock-up has been evaluated. The mock-up was erected for an actual project to verify the acceptance criteria for the skylight's technical, functional, and architectural details. The test was conducted at the Aluminum Technology Auxiliary Ind. (ALUTEC) facility in the Industrial Zone, Doha, Qatar. The fabricated full-scale mock-up has a rectangular plane configuration of 6.625 m (length) by 3.315 m (width) that belongs to a skylight measuring 36 m by 18 m. The ASTM E283, ASTM E331, and ASTM E330 standards were followed during the experiment. Air infiltration/exfiltration, static water penetration, structural performance, post-structural static water penetration, and structural proof loading tests were performed in an airtight chamber. After recording the residual displacements, the test findings for all the make-up components, namely steel tubes, glass, and aluminum sandwich panels, were determined and found within acceptable limits. [ABSTRACT FROM AUTHOR]

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The repair of underwater concrete structures is usually difficult work, requiring specialized materials and installation systems. This paper presents a carbon-textile-reinforced concrete (TRC) grouting system for underwater repair of concrete structures. One multi-purpose grout and two types of underwater grouts were considered in this study, and the bond performance between the substrate and grout was evaluated by a bi-surface shear test with cubic specimens. The bond strength of the repair material is greatly affected by the casting and curing conditions. When the multi-purpose grout is used, the average bond strength of the specimens cast and cured in dry conditions is only 22% of the specimens cast and cured in underwater conditions. On the other hand, the maximum difference in bond strength is, at most, 15.8% when non-dispersive, anti-washout grouts are used. Two types of installation methods were proposed and four full-scale RC slab specimens were repaired with the TRC grouting method, two for each installation method. Regardless of the installation method, the load levels that causes concrete cracking, steel yield, and the failure of specimens repaired with the TRC grouting system are at least 37.5%, 16.6%, and 21.7% greater than those of the unrepaired specimen, respectively. The test results further indicate that the influence of the grouting materials on the ultimate load-carrying capacity of the specimens repaired with the TRC grouting system is insignificant, and the maximum difference is, at most, 4%. [ABSTRACT FROM AUTHOR]

Canada faces a severe housing crisis, coupled with an aging and underutilized building stock. This issue is exacerbated in Eastern provinces like Québec and Ontario, where old unreinforced masonry (URM) buildings are prevalent and vulnerable to natural hazards such as earthquakes, floods, and soil settlements, therefore making their rehabilitation and repurpose projects particularly challenging. To address these issues and facilitate code-compliant building reuse and conversion into housing, this study presents a low-cost and sustainable timber retrofit cladding system for improving the structural response of URM buildings typical of Eastern Canada. The proposed design, devised to accommodate an energy layer as well to improve thermal performance, is tailored to the region's cold climate, low-to-moderate seismicity, and flood/soil settlement patterns, utilizing locally available construction practices and materials. In this paper, which focuses on quantifying mechanical performance alone, full-scale experimental testing of URM walls retrofitted with the proposed timber retrofit solution was conducted under in-plane diagonal compression. The results demonstrate that our novel design effectively delays brittle diagonal shear failures and transitions to more desirable mixed shear sliding mechanisms, significantly enhancing displacement capacity and post-cracking loadbearing performance to achieve ASCE 41–23 life safety (LS) thresholds. In addition to preliminary experimental and numerical data showing the potential for increasing URM thermal performance by over five times using biogenic insulation, the adopted retrofit solution enhances the maximum ultimate displacement of as-built walls under diagonal compression by 68 times on average, and recover 75.9 % of their loadbearing capacity on average after the first relevant was observed. Numerical simulations of tested walls is also conducted based on the Distinct Element Method (DEM), showing satisfactory agreement with experimental studies. Findings support the potential for broader application of our retrofit in the rehabilitation of Canada's existing URM buildings, offering a practical solution to increase housing supply while minimizing environmental impact. • A low-cost modular timber structural-energy retrofit is proposed for URM buildings. • In-plane diagonal compression tests are conducted for (un)retrofitted URM walls. • The proposed cladding retrofit system alters the failure mode from brittle to ductile. • Retrofitted walls retain a substantial loadbearing capacity after initial cracking. • This research addresses housing crisis and code-compliant building reuse in Canada. [ABSTRACT FROM AUTHOR]

Over the last two decades, the tidal energy industry has laid the groundwork for creating commercially viable tidal power generation projects to strengthen sustainable energy policies around the world. At the end of 2021, the cumulative installation of tidal stream technology that has been deployed in Europe reached 30.2 MW, where the majority of the installations are by small and medium-sized companies. Due to a growing demand among investors related to the global tidal energy industry, the reliability and safety of operational-stage tidal energy systems’ components are becoming increasingly important. In this context, companies, universities and research institutes are focusing on conducting large- and small-scale tests of tidal turbine elements to validate their projected design life, and major attention is being given to assessing the structural integrity of turbine blades. This review paper focuses on structural tests that have been reported for axial flow tidal turbine blades manufactured using composite materials around the world, highlighting the testing standards, equipment and instrumentation required. Overall, this review article discusses the state of the art in the structural testing of tidal turbine blades. In addition, it highlights the global concerns and research gaps to ensure the long-term sustainability of axial flow tidal turbine blades. In addition, the information contained in this article will be useful for formulating a smooth and reliable mechanism to enhance the evaluation process of the structural properties of tidal turbine blades in the future.

The certification of aircraft structures specifies various loads, possibly combined, to be considered to demonstrate its strength. In general, structural testing up to static failure is performed using proportional loading. In this study, the effects of loading with combinations of tension-shear-pressure are studied on large notched composite specimens. The VERTEX test rig is used. The Safe Life Domain method is proposed to validate whole domains of loading combination by means of a single envelope test. Envelope validation tests are implemented on tension-shear loadings with and without pressure, based on numerical predictions of the specimen failure and of the bench behaviour. Buckling mode variability and its impact on failure is considered, to show possible path-dependency of failure and thus highlight an ignored complexity of structure failure. Therefore, the numerous proportional tests needed for compliance demonstration can be reduced thanks to a few envelope tests instead. [ABSTRACT FROM AUTHOR]

This paper presents a new textile-reinforced concrete (TRC) installation method for strengthening structurally deficient or damaged reinforced concrete (RC) structures with grouting. In this study, cementitious grout was used as a matrix for the TRC system. TRC coupon specimens with different lap-splice lengths were tested under tension to determine the minimum textile lap-splice length. The minimum lap-splice length of the sand-coated textile was evaluated as 150 mm. The performance of the TRC-strengthened RC slabs with the proposed installation method. The lap-spliced textile was experimentally validated by a flexural failure test. Five RC slabs were strengthened by one ply of sand-coated carbon textile grid with and without the lap-splicing and 20 mm-thick cementitious grout and were tested in flexure. Among the TRC-strengthened RC slab specimens, two specimens were re-strengthened RC slabs with the TRC system. The TRC strengthened slab, for which the lap-splice length of the textile was 50% smaller than the minimum lap-splice length, failed at the load level of steel yield. On the other hand, the ultimate load-carrying capacity of the RC slabs strengthened by the TRC system with textile lap-splicing decreased by at least 6% relative to that without textile lap-splicing. Furthermore, the results of a flexural test for the TRC re-strengthened slabs indicate that the ultimate load-carrying capacity of the TRC re-strengthened slabs is almost the same as that of an undamaged slab strengthened with the TRC system. [ABSTRACT FROM AUTHOR]

Recently, new materials have been developed in the field of bridge design, one of which is FRP composite. To investigate this topic, the Polish National Centre for Research and Development has founded a research project, whose objectives are to develop, manufacture and test a typical FRP bridge superstructures. Two innovative ideas of FRP composite girder-deck structural systems for small and medium span bridges have been proposed. This paper describes the demonstrative bridges and presents the research results on their development and deployment. The finite element analysis and design procedure, structural evaluation in the laboratory and some results of the proof tests carried out on both bridge systems have been briefly presented.

To decrease development costs of aeronautical composite structures, industrials and academic researchers are turning to “virtual testing” methods. To help achieve this objective, a new methodology has been developed at the Institut Clément Ader. It is based on a complex loading test rig for technological specimens (more representative than the usual level of coupons) and the Discrete Ply Model (DPM), a model allowing the main damage occurring in composite structures to be simulated. This research focuses on the combined loading of CFRP plates after impact. In a previous work, plates were experimentally impacted and loaded after the impact in the VERTEX test rig and a methodology to transfer boundary conditions to the numerical model was validated using a simple model without damage. In the work presented here, the DPM was used to simulate both the impact and the complex loading after impact tests. Numerical results and experimental results showed satisfactory correlation. The research undertaken demonstrates that the impact damage has very little influence when the tests are performed at larger scales than coupons. It is therefore paramount to use a pyramidal approach to design and test composite structures, in order to avoid oversizing.

Experimental demonstration and performance evaluation on a shape-adaptive carbon composite full-scale hydrofoil manufactured using automated fibre placement (AFP) are presented in this paper. The experimental responses of the hydrofoil are validated with the finite element analysis (FEA) tools. The static performance of the hydrofoil was investigated using quasi-static cantilever load, whereas the dynamic response was studied using experimental modal analysis (EMA) to assess the structural quality of the manufactured hydrofoil. The variation between predicted and experimental modal and bending stiffness was found to be within 20%. Structural strains were also monitored using a network of distributed fibre optic sensors on the surface as well as embedded in conjunction with a network of strain gauges. The outcomes from this work demonstrates a framework of numerical analysis and experimental validation techniques using multiple sensors, which will pave the way towards further demonstrating the structural adequacy and performance of such hydrofoil, made of automated techniques and embedded with optical fibre sensor systems.

This paper investigates the problem of prime and test paths generation, which is an important problem in ensuring path coverage in software testing. Most existing methods for prime/test paths generation have little success in generating the set of all prime/test paths of structurally complex programs with high Npath complexity. This paper puts forward two novel methods for the generation of prime and test paths of highly complex programs, namely a vertex-based algorithm and a compositional method. The proposed vertex-based method enables a time-efficient approach for the generation of all prime paths, and the compositional method provides a highly time and space-efficient method for the generation of prime and test paths in cyclic control flow graphs with extremely large Npath complexity. We also implement the proposed algorithms as a software toolset for the generation of prime and test paths. Our experimental results on a set of complex programs indicate that the proposed approaches significantly outperform existing methods, especially for large and structurally complex programs.

Experimental testing has been considered as one of the most straightforward approaches to realize the structural behavior for earthquake engineering studies. Recently, novel and advanced experimental techniques, which combine numerical simulation with experimental testing, have been developed and applied to structural testing practically. However, researchers have to take the risk of damaging specimens or facilities during the process of developing and validating new experimental methods. In view of this, a small-scale structural laboratory has been designed and constructed in order to verify the effectiveness of newly developed experimental technique before it is applied to large-scale testing for safety concerns in this paper. Two orthogonal steel reaction walls and one steel T-slotted reaction floor are designed and analyzed. Accordingly, a large variety of experimental setups can be completed by installing servo-hydraulic actuators and fixtures depending on different research purposes. Meanwhile, a state-of-the-art digital controller and multiple real-time computation machines are allocated. The integration of hardware and software interfaces provides the feasibility and flexibility of developing novel experimental methods that used to be difficult to complete in conventional structural laboratories. A simple experimental demonstration is presented which utilizes part of the hardware and software in the small-scale structural laboratory. Finally, experimental layouts of future potential development and application are addressed and discussed, providing the practitioners with valuable reference for experimental earthquake engineering. [ABSTRACT FROM AUTHOR]