This paper presents an experimental and numerical investigation on the structural response of stainless steel trapezoidally corrugated web girders subjected to patch loading. Four girders were tested to failure, the length and position of the patch load within the corrugation profile were varied to investigate its impact on the ultimate load and failure modes. All four girders were made of lean duplex stainless steel (EN 1.4162/LDX 2101). Initial geometric imperfections were measured using a digital image correlation system. The load-displacement responses and the failure modes were analyzed in detail. In addition, geometrically and materially nonlinear analyses with imperfection included (GMNIA) were also performed. Measured initial imperfections were included in the model. The numerical model was verified against the experimental results. Stress distribution plots were also obtained numerically to further analyze the failure modes and the influence of the strain hardening capacity of stainless steel. Ultimate loads obtained experimentally were also compared with predicted resistances using theoretical models available in the literature. According to the results, neglecting the flange resistance to patch loads according to standard EC3:1-5 leads to a significant underestimation of the capacity of stainless steel and carbon steel corrugated web girders. However, considering the resistance from both the flange and web, the difference between the design model and test results is limited to a safe range of 3-12 % for all four tested girders.

Prestressed concrete offers a range of benefits compared to traditional reinforced concrete, but in some markets the application of post-tensioned structures has seen a decline in recent decades. A critical aspect of post-tensioned structures is the design of anchorage zones. This study introduces and evaluates an experimental method based on Distributed Optical Fibre Sensors (DOFS) to assess the behaviour of post-tensioned anchorage zones. Moreover, the effectiveness of steel fibre reinforced concrete (SFRC) is also compared to various setups using conventional reinforcement systems. The aspects analysed include load-deformation behaviour, initial crack formation, and subsequent crack development. The research, based on six tested samples, shows that the application of DOFS in the presented setup holds great potential. Furthermore, the findings indicate that using exclusively SFRC at a volume fraction of 0.5%, without passive reinforcement is not recommended. However, combining SFRC with standard helical reinforcement around the anchorage block appears sufficient to meet desired structural performance, as evidenced by comparisons to control specimens.

The response of masonry structures to impacts is a topic of significant importance due to its implications in structural integrity and safety. In this paper, the impulsive response of unreinforced brick masonry walls to impacts was investigated through a series of laboratory pendulum tests. Four double-wythe clay brick masonry wall strips were constructed between reinforced concrete slabs and subjected to moderate-velocity impacts. The tests included both point-load and line-load impacts, with a non-rigid support condition for the upper wall support to simulate realistic axial load applications. Measurements included: load cells monitoring the axial load applied to the top of the walls, capturing the arching generated upon impact; high-speed cameras used in conjunction with 3D DIC, to monitor strain rates and crack evolution on the wall surface; and 3D LiDAR scans, to support the documentation of post-test observed damage. The findings offered a comprehensive and detailed analysis of the structural response of brick masonry walls subjected to impacts. By focusing on specific response metrics, the study elucidated the various failure mechanisms generated by the impacts. Additionally, the energy transferred during the impacts was quantified, providing a direct measure of the energy absorption capacity of the walls and its correlation with the observed failures.

Wedge splitting tests were conducted on a granite and a gneiss with similar mineralogy but different microstructure. The basic properties of the two rock types were characterized by petrographic analyses and mechanical tests. The granite specimens were split in one material direction, perpendicular to the rift plane, and the gneiss specimens were split in three different material directions, parallel and perpendicular to the foliation (and along and across a lineation). The effect of having a large blunt versus a sharp notch on the crack initiation was studied in the granite. The wedge splitting tests are unconventional for testing rocks and allowed to study the crack initiation and propagation under mode I loading condition in the quasi-brittle granite and brittle gneiss. The fracture energy and strain energy release rate were calculated. The strain energy release rate for gneiss, when splitting along and across the foliation, was around 45% and 60% of the values for the structurally isotropic granite. The fracture toughness was calculated from the strain energy release rate and was larger than corresponding values obtained from linear elastic fracture mechanics (LEFM). There was an effect on the early cracking stages by using a sharp notch compared with using a large blunt notch on the granite specimens, but the required largest force to split the specimens remained the same for the two notch types. The crack initiation started at a splitting force corresponding to 78% and 90% of the maximum splitting force on the specimens with a sharp notch and a large blunt notch, respectively. The results with a full force-displacement response during the crack propagation obtained for the brittle gneiss are unique. Most fracture mechanics results on rock materials are obtained from standard tests and LEFM and not via the measured strain energy release rate.

Reinforced concrete (RC) protective structures require a large energy absorption capacity if they are to effectively withstand impulse loading due to blast or impact. Such structures may be subjected to both single and repeated impulse loading but there are just a few studies for the latter case. Therefore, in this study, experiments were conducted on RC beams, which were subjected to single or repeated drop-weight impacts. The beam response during impact was studied using a high-speed camera and digital image correlation. To determine the total energy absorption capacity, the impact-loaded beams were subjected to static loading until failure and the results compared to those of statically loaded reference beams. The total energy absorption capacity was of the same order or higher for beams previously subjected to impact loading, with a strong impact resulting in a greater increase. For tests in which the total impact energy was kept constant, repeated impact loading caused increased local damage, whilst decreasing the total energy absorption capacity.

Strategic reuse of disassembled concrete elements in new buildings may be one of the solutions that will support the transition to circular construction. However, there are no EN standards instructing how to tackle quality assurance of concrete elements for reuse. The work on the Swedish standard for the reuse of prefabricated concrete elements was initiated within the national standardisation committee based on multiple experiences from previous and ongoing projects. This paper describes a methodology for material and structure investigations combining non-destructive on-site testing with traditional laboratory tests of samples extracted from the structures. The proposed method divides structures into four types depending on their production technology and according to CE-marking rules: 1) Hollow-core decks, 2) Prefabricated elements with prestressed reinforcement, 3) Prefabricated elements with standard reinforcement 4) In-situ cast concrete elements. The proposed approach was validated on the results from six demonstration projects, where real buildings in Stockholm and Gothenburg (Sweden) were reused or prepared for reuse to different extents. The analysed buildings had different functions (housing, office, parking) and structures (prefabricated elements and in-situ cast concrete), representative of the Swedish building stock. One of the buildings has been already dissembled and the prefabricated hollow-core slabs have been successfully reused for a housing construction.

The development of an innovative rock anchor prototype manufactured using high strength steel sheets produced locally in Sweden is the core of the PROWIND concept. Steel sheets provide a design freedom to easily manufacture complex geometries, which can be advantageous to enhance the shear force transmission in the bond-length segment of the anchor. The underlying challenge of this concept has been to design a solution which meets the design requirements of today and future technological advancements, all while keeping conventional installation practices in mind. The project followed a 4-step development process: (1) concept analysis and modelling, (2) small-scale prototypes testing and (3) large scale lab-validation and lastly (4) field validation. The performance of the developed rock anchor prototype and grouting material was experimentally quantified on both small and large-scale test specimens and also validated in full scale in the field concerning installation process, proof-loading and maintaining the prestress over time. The PROWIND anchors with the end feature with ribbed design have 4-5 times higher load bearing capacity. The experience from the anchor installation proved that the developed grout and anchors are faster and easier to install. The field test in two different geological conditions has proven that the news design is reducing the required anchorage length to just 1 meter. The restressing of anchors is fully possible with the proposed lock-off solution with a nut. All of those contribute to lower costs of installations and possibly longer service-life.

Prestressed concrete structures have numerous advantages over conventionally reinforced concrete, though the usage of post-tensioned structures has declined over the last two decades. An essential design detail in post-tensioned structures is the anchorage zones. In this study an experimental comparison is presented for post-tensioned anchorage zones. The study evaluates the load-deformation response and cracking of three different configurations. In total, six specimens are tested experimentally by subjecting them to centric loading until clear crack formations were observed. The evaluation and comparison of the three different configurations are done by comparing the data obtained from the tests. The results presented in this paper are expected to provide further knowledge to develop and improve the contemporary design approach and construction of bridges.

This dataset contains the results of laboratory quasi-static monotonic four-point bending tests conducted at RISE Research Institutes of Sweden on eleven natural-scale unreinforced brick masonry walls. The walls were spanning vertically between two reinforced concrete slabs and were tested under three different support conditions defined according to the American manual UFC 3-340-02: simply supported, rigid, non-rigid. The influence of these support conditions on the out-of-plane behavior of the walls was studied on elements with varying thickness – single and double wythe – and subjected to different levels of axial compression (or overload). The walls were tested inside of a bi-axial test setup that allowed not only the lateral, out-of-plane force but also the axial, arching action to be measured throughout the tests. Optical full-field displacement measurements were also acquired by two systems of cameras making use of the 2D and 3D Digital Image Correlation (DIC) technique. The data generated from these tests are made here available to support further investigations on masonry structures subjected to extreme lateral, out-of-plane actions. The dataset includes 3 compressed folders, ordered from 01 to 03, along with an auxiliary document describing the content and organization of the dataset. The data presented here are described in the following research article: Godio M, Flansbjer M, Williams Portal N (2023). Single- and double-wythe brick masonry walls subjected to four-point bending tests under different support conditions: simply supported, rigid, non-rigid, Construction and Building Materials To cite this dataset, please refer to the article. The Authors

In this paper, the shear strength of corrugated web girders made of EN 1.4162/LDX 2101 stainless steel is investigated. Four full-scale trapezoidal corrugated web girders were tested under shear. Before conducting the tests, DIC was used to measure the real geometric imperfections in the web panels. Complementary finite element analysis studies were conducted to assess the sensitivity of the shear strength to initial imperfections. The experimental results indicated that all the tested girders with a local slenderness ratio of & lambda; = 0.7 attained the shear yield strength, which was then followed by strain hardening in the material at a level that was 8-18% higher than the yield strength. This implies that the Eurocode's limit of & lambda; = 0.25 to attain the plastic shear strength in corrugated webs can be quite conservative for stainless steel. According to the findings of the imperfection sensitivity studies, an initial geometric imperfection based on the first eigen buckling mode and with a maximum amplitude of amax/200, where amax is the maximum corrugation fold length, yielded ultimate strength within 3% of the test results. When the amplitude was increased to hw/200, where hw is the web height, the ultimate strength was estimated to be 25% lower on average than in the experiments. In three of the studied girders, initial imperfections with other forms than the first buckling mode were found to be more critical. Further, it was found that regardless of mode number, mode shapes that are more extended over the web panel result in a higher degradation of the ultimate shear strength.

Unreinforced brick masonry makes up today a significant piece of the European built environment, including not only residential buildings but also strategically important structures that are not designed to withstand blasts and impacts. Yet, it is difficult to accurately estimate the response of these structures and the extent of damage they sustain during such extreme loading conditions. This paper presents the implementation and discusses the results of laboratory impact tests conducted on natural-scale double-wythe unreinforced brick masonry walls, a typology that is frequently found in Northern Europe. The walls were spanning vertically between two reinforced concrete slabs and were subjected to low-velocity drop-weight pendulum tests in which they were repeatedly hit until the opening of a breach in the centre of the wall. The tests were instrumented with both hard-wired and optical measurements, the latter consisting of high-speed cameras and digital image correlation techniques, to face the difficulty of observing cracks and determining the deflections of the walls with adequate accuracy at the time of the impact. Investigated in these tests were the out-of-plane response of the walls and their capacity to resist the impacts. The axial load applied on the top of the walls was varied for two wall configurations and monitored throughout the tests to study the effect of arching on the failure mechanism produced and number of repeated hits needed to open the breach. Of interest was also the evidence of cracking, more specifically the way it initiated on the undamaged walls and next propagated upon consecutive hits. The data generated from these tests are made available to support further investigations on masonry structures subjected to extreme actions.

A recent research project investigating the structural safety of self‐supporting glass components aims to contribute to the development of future guidelines for architectural glazing applications. A specific task within the project was concerned with extending the current knowledge about the effect of impact loading and related testing methods regarding the safety of glass structures. The method described in the paper combines high‐speed 3D‐DIC and FEA to gain a deeper understanding of the dynamic structural response of self‐supporting glass balustrade components, which in turn can enhance product development and user safety.

Masonry walls are bulky and heavy and have therefore the potential to act naturally as a protective system to blasts. Yet, they are known to have a limited flexural and torsional capacity, particularly when unreinforced. When exposed to shockwaves, they experience out-of-plane failure mechanisms which may affect the overall stability of the building and engender flying debris inside the building. The out-of-plane response of unreinforced masonry walls to blasts depends on many factors characterizing both the wall and blast action, making any sort of prediction difficult. In this context, experimental tests and numerical models become key tools that can be used to study the wall's response on a case-by-case basis. This review covers the major experimental and numerical approaches to assess the out-of-plane response of unreinforced masonry walls subjected to blasts. A methodological appraisal is used for the test methods, focusing on the preparation of the test items and test setup, the boundary conditions and failure mechanisms investigated, as well as the commonly employed measurement techniques. The survey on the modelling approaches includes key topics such as level of detail and cost, and reports strategies to model the wall and blast scenario. The review provides a thematic analysis of the available literature, aimed to assist the analyst in selecting a suitable tool for the investigation of masonry in the field of blast engineering. Furthermore, the findings presented herein can support amendments of existing codes and guidelines pertaining to the design of protective masonry structures.

Recycled concrete aggregate (RCA) was processed from reinforced concrete edge beams sourced from a demolished bridge. This material replaced different ratios of coarse aggregate in a benchmark concrete. The tensile behavior of the developed concrete mixes was characterized via monotonic and cyclic uniaxial tensile tests performed on notched cylinders. Such tensile tests allow for the quantification of the fracture energy and softening behavior of the concrete. Moreover, acoustic emission (AE) measurements were conducted in conjunction with the cyclic tests to characterize e.g. micro-crack initiation and development, as well as crack localization. The tensile behavior of the various materials was found to be similar with minimal variation in the results. However, the softening behavior suggests that the RCA materials are slightly more brittle compared to both the mother and benchmark materials. The corresponding AE measurements also indicated similarities between the micro-crack initiation and development for these mixes. It can be constituted that if the concrete used to produce RCA is of high quality and from one source, the resulting RAC will have adequate tensile properties with minimal variation, despite the aggregate replacement ratio.

Reinforced concrete structures are often damaged by corrosion, which affects the interaction between reinforcement bars and concrete. Earlier studies mostly applied artificial corrosion to test the bond between deformed bars and concrete. However, there is a lack of knowledge on the effects of natural corrosion on plain bars. In this paper, 20 beams with naturally corroded plain bars and varying amount of damage were taken from an 80-year-old bridge and tested in three-point bending. All but three of the specimens anchored the yield force of the bars after the opening of one or two major bending cracks. At large deflections, the load-carrying mechanism changed from beam to arch action. Eventually, end-slip of the reinforcement bars was observed. The bars were extracted, cleaned, three-dimensionally scanned, and tested in tension. The average bond strength in the unyielded zone was found to be equal to 7.39 MPa, with a standard deviation of 3.33 MPa. The casting position was identified as an important factor: when uncorroded, bottom-cast bars had a higher bond strength than that of top-cast bars. However, they were more prone to splitting cracks and, consequently, loss of bond strength for small corrosion levels. Top-cast bars had increasing bond strength with increasing corrosion levels, owing to the absence of external cracks. These differences were likely related to a denser concrete surrounding the bottom-cast bars. The remaining bond capacity in the yielded zones was evaluated to be approximately 1.0 MPa.

The Swedish Nuclear Fuel and Waste Management Company developed a method for the final disposal of canisters for spent nuclear fuel in tunnels at depths of about 500 meters. The concept for closure of the deposition tunnels is based on a bentonite seal supported by a spherical concrete dome structure. In order to fulfil the requirements specific to the repository concept, a special mix of low-pH self-compacting concrete was developed. A series of large-scale castings and laboratory tests were conducted to gain experience on this low-pH concrete mix, in conjunction with the full-scale demonstration test of an unreinforced concrete dome plug in the underground hard rock laboratory in Aspo, Sweden. The laboratory tests aimed at studying the creep properties under high sustained compressive stresses of the low-pH concrete mix, its shrinkage properties and the properties of the rock-concrete interface. This paper provides an overview of these tests and analyses the latest results of the recently completed creep tests, which include 6 years of measurements. These results allow to improve understanding of the structural behaviour of the concrete plug and to assess the effects of the very high pressure acting on the plug on its deformations, cracking and water tightness.

A new methodology based on monitoring of crack propagation during small-scale mechanical tests on sawn rock prisms under tension has been developed. The methodology includes a combination of differ ...

The work carried out within Task 2 Experimental work of the AForsk funded project Structural safety of glass components is presented in this report. The main goal of this project was to improve t ...

As a part of the SESBE (Smart Elements for Sustainable Building Envelopes) project, non-load bearing sandwich elements were developed with Textile Reinforced Reactive Powder Concrete (TRRPC) for outer and inner facings, Foam Concrete (FC) for the insulating core and Glass Fiber Reinforced Polymer (GFRP) continuous connectors. The structural performance of the developed elements was verified at various levels by means of a thorough experimental program coupled with numerical analysis. Experiments were conducted on individual materials (i.e., tensile and compressive tests), composites (i.e., uniaxial tensile, flexural and pull-out tests), as well as components (i.e., local anchorage failure, shear, flexural and wind loading tests). The experimentally yielded material properties were used as input for the developed models to verify the findings of various component tests and to allow for further material development. In this paper, the component tests related to local anchorage failure and wind loading are presented and coupled to a structural model of the sandwich element. The validated structural model provided a greater understanding of the physical mechanisms governing the element’s structural behavior and its structural performance under various dead and wind load cases. Lastly, the performance of the sandwich elements, in terms of composite action, was shown to be greatly correlated to the properties of the GFRP connectors, such as stiffness and strength.