An innovative strengthening technique is applied for the first time in this study to provide flexural strengthening in two-way reinforced concrete (RC) slabs supported on edge beams. The technique comprises external bonding of textiles on the tension face of RC slabs through the use of polymer-modified cement- based mortars. The textiles used in the experimental campaign comprised fabric meshes made of long stitch-bonded fibre rovings in two orthogonal directions. The specimens measured 2 x 2 m in plan and were supported on hinges at the corners. Three RC slabs strengthened by textile reinforced mortar (TRM) overlays and one control specimen were tested to failure. One specimen received one layer of carbon fibre textile, another one received two, whereas the third specimen was strengthened with three layers of glass fibre textile having the same axial rigidity (in both directions) with the single-layered carbon fibre textile. All specimens failed due to flexural punching. The load-carrying capacity of the strengthened slabs was increased by 26%, 53%, and 20% over that of the control specimen for slabs with one (carbon), two (carbon) and three (glass) textile layers, respectively. The strengthened slabs showed an increase in stiffness and energy absorption. The experimental results are compared with theoretical predictions based on existing models specifically developed for two-way slabs and the performance of the latter is evaluated. Based on the findings of this work the authors conclude that TRM overlays comprise a very promising solution for the strengthening of two-way RC slabs.

Title: Influence of physiotherapist intervention on shoulder muscular imbalance and movement stereotype in users of mechanical wheelchair. Objectives: The aim of the work is to find out to what extent a twelve-week strength training under the professional guidance of a physiotherapist can affect the users of mechanical wheelchairs (paraplegics) and their functional muscle tension in the shoulder area. Methods: This pilot multiple qualitative research took place from January to July 2021. Three paraplegics aged 39 to 46 participated voluntarily in the research. A kinesiological analysis was performed on each proband with an examination of the movement stereotype while riding a mechanical wheelchair. A diagnostic method with a tensiomyograph was performed for individual muscles of the shoulder girdle. Kinesological analysis and muscle measurements were performed before and after the intervention, which took place three times a week. Due to the unfavorable epidemic situation, it was carried out in the form of video transmission at home. The comparative method was used in the comparison section before and after the end of the physiotherapist's intervention during the training cycle of each proband. The obtained results were processed by the TMG 100 software, which meets the requirements for data...

A proposal how to conduct a compression test of reinforced concrete objects with one beam inserted from both sides exposed to a four-point bending. A theoretical proposal of the most appropriate form of reinforcement of the reinforced concrete object including a suggestion how to increase its tensile strength based on the chosen crushing load and the positioning of the beam (static calculation). Presentation of the project, static compression test measurement and all the other necessary measurements (elastic modulus, strenth of the material etc.). Development of a mathematical model with the help of Atena software. Evaluation and comparison of the results in analytical and experimental part of the project. Recommendations for implementation of similar experimental tests.

Die vorliegende Arbeit befasst sich mit der Verbundverankerung des neuen Verstärkungsmaterials textilbewehrter Beton für Stahlbetonbauteile. Der Detailpunkt der Verankerung mit den Mechanis-men der Kraftübertragung von der textilbewehrten Verstärkungsschicht in den Altbeton wurde auf experimentellem Weg an unterschiedlichen Probekörperformen untersucht. Dazu wurden verschie-dene Haftzug-, Filamentgarnauszug- sowie Schubversuche durchgeführt. Nach der Klärung der grundlegenden Phänomene beim Verbundbruchverhalten von Verstärkungs-schichten wurden zugehörige Versagenskriterien näher beleuchtet. Ein mögliches Versagen des inneren Verbundes wurde durch zusätzlich in das Versuchsprogramm aufgenommene Filamentgar-nauszugsversuche untersucht. Für die Verankerung sind zwei Versagensebenen zu berücksichtigen, die eine getrennte Betrachtung erfordern: der Altbetonuntergrund und die Ebene der textilen Be-wehrung. Mit Hilfe experimenteller Haftzuguntersuchungen wurde ein breit gefächertes Spektrum möglicher Einflussparameter auf die Tragfähigkeit des Verbundes in der Ebene der textilen Bewehrung unter-sucht. Den einzelnen Einflussfaktoren kommt dabei eine unterschiedliche Bedeutung zu. Den aus-schlaggebenden Einfluss auf die Tragfähigkeit des Haftverbundes in der Ebene der textilen Bewehrung liefert die textile Bewehrung selbst. Es wurde ein geeignetes Verfahren zur Ermittlung eines wirksamen Flächenanteiles der textilen Bewehrungsstrukturen entwickelt, welches die Grund-lage für die weiterführenden Betrachtungen zum Verbundversagen durch Delamination in der Ebe-ne der textilen Bewehrung bildet. Das Verbundtragverhalten unter Schubbeanspruchung bildet den Kern der vorliegenden Arbeit. Spezielle Eigenheiten des textilbewehrten Betons werden aufgezeigt und Lösungsvorschläge erar-beitet. Da sich das Verhalten von Verstärkungsschichten aus textilbewehrtem Feinbeton beträcht-lich von bekannten Klebeverbindungen unterscheidet, sind hier völlig neue Wege zu beschreiten. In Zusammenarbeit mit dem Institut für Photogrammetrie und Fernerkundung wurde ein neues, riss-bildorientiertes Messverfahren entwickelt. Anhand eines Beispielversuchs wird diese neu entwi-ckelte Methode vorgestellt und verbleibende Problempunkte diskutiert. Die Ergebnisse dieser Messungen haben gezeigt, dass es mit dem derzeitigen Kenntnisstand nicht möglich ist, für das Verstärkungsmaterial Textilbeton eine Schubspannungs-Schlupf-Beziehung anzugeben. Nach An-sicht der Verfasserin ist die Verwendung einer solchen Modellvorstellung nur für Verstärkungsma-terialien mit linear-elastischem Materialverhalten geeignet. In der vorliegenden Arbeit werden einige alternative Modellvorschläge für die Beschreibung des Verbundverhaltens angegeben. Separate Modellvorschläge für die Verbundtragfähigkeit unter Haft-zugbeanspruchung und unter Schubbeanspruchung wurden zu einer Interaktion zusammengeführt. Diesem wurden weitere alternative Modellvorschläge wie z. B. die Betrachtung als Stabwerk mit veränderlicher Druckstrebenneigung gegenübergestellt.

[pt] É descrito neste trabalho um programa experimental sobre a aderência entre os compósitos com tecido de fibras de carbono e o concreto. Este programa experimental consistiu em ensaios de tração-compressão de corpos-de-prova compostos de dois blocos de concreto (móvel e fixo) colados por tiras de tecido de fibra de carbono coladas nos lados opostos desses blocos. Foram ensaiados nove corpos-de-prova, com três resistências à compressão aos 28 dias de 20,5 MPa, 28,7 MPa e 38,1 MPa e duas larguras do tecido iguais a 50 mm e 100 mm. Todos os corpos-de-prova foram concretados, instrumentados e ensaiados no Laboratório de Estruturas e Materiais da PUC-Rio. O objetivo deste trabalho foi estudar a influência da resistência do concreto e da largura do tecido de fibra de carbono sobre a resistência de aderência do sistema. Os resultados mostraram que a resistência de aderência pode ser considerada independente da resistência do concreto e da largura do tecido. Foi obtido, neste estudo, um valor característico de 1,45 MPa para a resistência de aderência. / [en] An experimental study on the bond between carbon fiber fabric composites and concrete is described in this work. This experimental program consisted of tension-compression tests of specimens with two concrete blocks (movable and fixed) jointed by carbon fiber fabric strips bonded on two opposite sides of these blocks. Nine specimens, with three concrete compressive strength of 20,5MPa , 28,7MPa and 38,1MPa at 28 days and two fabric width of 50 mm and 100 mm, were tested. All specimens had the same geometrical characteristics. All the specimens were cast, instrumented and tested in the Structural and Materials Laboratory at PUC-Rio. The objective of this work was to study the influence of concrete strength and the width of the fabric on the bond strength of the system. The results showed that the ultimate bond strength may be considered independent of concrete strength and of the width of the fabric. A characteristic value of 1.45 MPa was found for the bond strength.

In Sweden, a large share of residential buildings was built more than 50 years ago. Consequently, old materials, poor maintenance, and corrosion can affect the structural performance of these buildings. Additionally, these buildings do not meet the latest energy efficiency and Eurocode regulations. Building retrofits can improve structural strength and resident safety, as well as the energy efficiency of the buildings. Common retrofitting methods are unsustainable in terms of costs, duration, and disruptions to resident’s lives. A sustainable method for structural and energy upgrades is needed in order to retrofit such kind of structures in an efficient way. This master thesis aims to identify an innovative structural and energy retrofitting solution for reinforced concrete buildings that are reaching the end of their service life as well as to provide an environmental impact assessment of this whole process. A multi-family building built in 1972 in Ronneby, Sweden, with reinforced concrete load-bearing walls and slabs was considered as a case study. An integrated retrofitting strategy based on an addition of cross-laminated timber (CLT) panels, insulation, and claddings to the external walls to increase the horizontal load-bearing capacity and energy efficiency of the building was applied in this study. Steel tubes and fiber-reinforced polymers (FRP) are used to increase the load-bearing capacity of the internal load-bearing walls and slab compared to the original ones, mostly for vertical loads. For the structural analysis based on the Eurocode regulations, the software RFEM was used to model and analyze the building before and after retrofitting. In addition to that, dynamic thermal simulation was performed with VIP-Energy software to analyze the service life energy consumption before and after retrofitting of the building. Life cycle assessment following the European standard SS-EN 15978 was used to assess the environmental impacts including global warming potential (GWP), acidification potential (AP), and eutrophication potential (EP). The environmental impact of the existing building was compared with the retrofitted case, during a 50-year service life. The results show that after the retrofitting in the load-bearing walls, the internal shear forces induced by wind loads decreased by 38%. Also, the load-bearing capacity of the slabs was increased by 350% in the critical areas. Regarding GWP, AP and EP all decreased by 30% in the retrofitted case. The results indicate that by retrofitting the building, structural performance and safety increase, and moreover the environmental impact of the building is minimized.

The purpose of this study is to investigate physical education teachers, from the upper secondary school's, view of martial arts teaching in the subject of physical education. The study also examined physical education teachers' views on challenges and self-strengthening elements that are linked to martial arts teaching in the subject of physical education. The study was carried outwith six semi-structured in-depth interviews with physical education teachers from western. The results showed that a large proportion of the teachers had similar views on the suitability of martial arts in school. Their responses were consistent with previous research on the benefits of martial arts lessons for students. Based on self-strengthening elements and challenges with martial arts, the teachers had different points of view. This was due to the different levels of knowledge in the martial arts.

Mitigation of the blast risk associated with terrorist attacks and accidental explosions threatening critical infrastructure has become a topic of great interest in the civil engineering community, both in Canada and abroad. One method of mitigating blast risk is to retrofit vulnerable structures to resist the impulsive effects of blast loading. A comprehensive re-search program has been undertaken to develop fibre reinforced polymer (FRP) retrofit methodologies for structural and non-structural elements, specifically reinforced concrete slabs and walls, subjected to blast loading. The results of this investigation are equally valid for flexure dominant reinforced concrete beams subject to blast effects. The objective of the research program was to generate a large volume of research data for the development of blast-resistant design guidelines for externally bonded FRP retrofit systems. A combined experimental and analytical investigation was performed to achieve the objectives of the program. The experimental program involved the construction and simulated blast testing of a total of thirteen reinforced concrete wall and slab specimens divided into five companion sets. These specimens were subjected to a total of sixty simulated explosions generated at the University of Ottawa Shock Tube Testing Facility. Companion sets were designed to study one- and two-way bending, as well as the performance of specimens with simply-supported and fully-fixed boundary conditions. The majority of the specimens were retrofitted with externally bonded carbon fibre reinforced polymer (CFRP) sheets to improve overall load-deformation characteristics. Specimens within each companion set were subjected to progressively increasing pressure-impulse combinations to study component behaviour from elastic response up to inelastic component failure. The blast performance of companion as-built and retrofitted specimens was quantified in terms of measured load-deformation characteristics, and observed member behaviour throughout all stages of response. The results show that externally bonded FRP retrofits are an effective retrofit technique to improve the blast resistance of reinforced concrete structures, provided that debonding of the composite from the concrete substrate is prevented. The test results also indicate that FRP retrofitted reinforced concrete structures may survive initial inbound displacements, only to failure by moment reversals during the negative displacement phase. The experimental test data was used to verify analytical techniques to model the behaviour of reinforced concrete walls and slabs subjected to blast loading. The force-deformation characteristics of one-way wall strips were established using inelastic sectional and member analyses. The force-deformation characteristics of two-way slab plates were established using commonly accepted design approximations. The response of all specimens was computed by explicit solution of the single degree of freedom dynamic equation of motion. An equivalent static force procedure was used to analyze the response of CFRP retrofitted specimens which remained elastic after testing. The predicted maximum displacements and time-to-maximum displacements were compared against experimental results. The analysis indicates that the modelling procedures accurately describe the response characteristics of both retrofitted and unretrofitted specimens observed during the experiment.

Of the 700 offenders that are released from prison each year, seven in ten will be rearrested. There are a number of barriers face by released offenders that inhibit their successful reentry. These barriers include: mental health illness, limited work experience, lower education, substance abuse, lack of transportation, homelessness and poverty strain of family ties and/or close relationships. This paper explores the impact of social support on recidivism rates through a systematic review of the literature surrounding prosocial support. The implications for social work practice and research are also discussed.

The present work aims at finding suitable mineral-bonded strengthening layers to protect steel-reinforced concrete (RC) structures from impact events. The strengthening layers are applied to the impact-facing side and absorb large parts of the impact energy. In this way, they protect the RC structures from the impact events. The multilayered strengthening layers consist of a cover layer and a damping layer. The cover layers possess a high strength and a high modulus of elasticity. The impactor directly hits the cover layer, which spreads the impact force to larger areas of the damping layer below. The strengths and moduli of elasticity of the damping layers are minor, and they absorb impact energy, converting it into friction, heat, or potential energy. Several materials have been tested as damping layers, including a concrete mixed with waste tire rubber aggregates, two types of lightweight concrete, and two types of infra-lightweight concrete. The cover layers tested include carbon-fiber-reinforced concrete and various short-fiber-reinforced concretes, some of which are reinforced with 3D hybrid pyramidal truss reinforcing structures. At first, the dynamic material properties were determined with the help of a tensile and a compressive split Hopkinson bar. The small-scale experiments serve to investigate the dynamic material behavior. At the same time, they are the basis for an eventual later numerical analysis of the strengthening layers. A numerical analysis enables the variation of the material parameters. Lastly, large-scale tests with RC cuboids that were fully supported were performed. A choice of cover and damping layer materials was compared to unstrengthened RC cuboids. The first set of experiments strived to vary the damping layer to find the most suitable one that absorbs the highest amount of incident energy, thus minimizing the damage to the RC cuboid. Afterward, the best damping layer material was combined with different cover layers to figure out the best cover layer option.:Abstract i Kurzfassung iii List of Symbols xv List of Abbreviations xix 1 Objectives, Working Program, and Structure 1 1.1 Motivation 1 1.2 Overall Objectives 1 1.3 Working Program 1 2 State of the Art and Theoretical Background 3 2.1 Impact on Structural Elements 3 2.1.1 Soft and Hard Impact 3 2.1.2 Failure Modes Under Hard Impact Conditions 3 2.1.3 Large-Scale Impact Experiments 4 2.1.4 Impact Protection Layers 4 2.2 Introduction of Impact Protection Principles 4 2.2.1 Impact Protection in Nature 4 2.2.2 Technical Impact Protection Examples 9 2.2.3 Summary of Impact Protection Principles and Usable Materials 14 2.3 Mineral-Bonded Damping Layer Materials 15 2.3.1 Waste Tire Rubber Concrete 15 2.3.2 All-Lightweight Aggregate Concrete 16 2.3.3 Infra-Lightweight Concrete 17 2.4 Mineral-Bonded Cover Layer Materials 18 2.4.1 Strain-Hardening Cementitous Composites 18 2.4.2 Textile Reinforced Concrete 19 2.4.3 Hybrid-Fiber Reinforced Concrete 19 2.5 Bond Between Different Strengthening Layers 20 3 Materials under Investigation 21 3.1 Specimen Preparation 21 3.2 Damping Layer Materials 22 3.2.1 Waste Tire Rubber Concrete (WTRC) 22 3.2.2 All-Lightweight Aggregate Concrete With Liapor Aggregates (ALWAC-L) 23 3.2.3 All-Lightweight Aggregate Concrete With Ulopor Aggregates (ALWAC-U) 23 3.2.4 Porous Lightweight Concrete (PLC) 23 3.2.5 Infra-Lightweight Concrete (ILC) 23 3.2.6 Comparison of the Damping Layer Materials 24 3.3 Cover Layer Materials 27 3.3.1 Pagel TF10 CARBOrefit With Carbon Textile Reinforcement (P-C) 27 3.3.2 Strain-Hardening Limestone Calcined Clay Cement (SHLC3) 27 3.3.3 Comparison of the Cover Layer Materials 28 3.4 Partially Loaded Areas 30 4 Methodology of Split Hopkinson Bar Experiments 35 4.1 Experimental Setup and Methodology 35 4.1.1 Compressive Split Hopkinson Bar 35 4.1.2 Tensile Split Hopkinson Bar 36 4.1.3 Instrumentation 39 4.2 Evaluation Process 39 4.2.1 Impedance 40 4.2.2 Raw Data Analysis, Filtering, and Time-Shifting of Pulses 41 4.2.3 Stresses and Strains 42 4.2.4 Deformations 50 4.2.5 Forces and Impulses 51 4.2.6 Energy Absorption 52 4.2.7 Fracture Energy 53 4.2.8 Averaging of the Results 54 5 Compressive Split Hopkinson Bar Experiments 57 5.1 Failure Modes 57 5.2 Stresses and Strains 58 5.2.1 Dynamic Compressive Strength 58 5.2.2 DIF 59 5.3 Deformations 60 5.4 Forces and Impulses 61 5.4.1 Relative Transmitted Force 61 5.4.2 Impulse Transmission 63 5.4.3 Reduction of the Pulse Inclination 64 5.5 Energy Absorption 64 5.6 Conclusions 66 6 Tensile Split Hopkinson Bar Experiments 69 6.1 Failure Modes 69 6.2 Stresses and Strains 70 6.2.1 Dynamic Tensile Strength 70 6.2.2 DIF 71 6.3 Deformations 72 6.4 Forces and Impulses 73 6.4.1 Relative Transmitted Force 73 6.4.2 Impulse Transmission 74 6.4.3 Reduction of the Pulse Inclination 75 6.5 Energy Absorption 75 6.6 Fracture Energy 77 6.7 Conclusions 78 7 Methodology of Cuboid Experiments 79 7.1 Experimental Program 79 7.1.1 Specimen Dimensions and Experimental Setup 79 7.1.2 Experimental Scheme 81 7.2 Measurements Taken During the Experiments 83 7.2.1 Light Barriers 84 7.2.2 Resistor 84 7.2.3 Strain Gauges 84 7.2.4 Laser Doppler Vibrometer 85 7.2.5 Accelerometers 85 7.2.6 Load Cells 85 7.2.7 High-Speed Cameras and DIC 85 7.3 Measurements Taken Before and After the Experiments 86 7.3.1 Impactor Indentation 86 7.3.2 Burst Mass 86 7.3.3 Ultrasonic Pulse Velocity Measurements 86 7.3.4 Stimulation 87 7.4 Evaluation Process 88 7.4.1 Fracture and Damage Process 88 7.4.2 Impactor Velocity, Deceleration, Force, Stress, and Stress Rate 88 7.4.3 Impactor Indentation, Strain, and Strain Rate 90 7.4.4 Vertical Cuboid Deformation, Velocity, and Acceleration 92 7.4.5 Lateral Cuboid Deformation, Velocity, and Acceleration 93 7.4.6 Relative Cuboid Elongation in X- and Y-Direction 93 7.4.7 Strain Measurements on the Reinforcement Bars 94 7.4.8 Path and Derivative of the Support Forces 95 7.4.9 Burst Mass 96 7.4.10 Ultrasonic Pulse Velocity Measurements 96 7.4.11 Stimulation 97 7.4.12 Impulse and Momentum Conservation 99 7.4.13 Energy Conservation 100 7.4.14 Estimation of the Eigenfrequency of the Cuboids 101 8 Damping Layer Variation in Cuboid Experiments 103 8.1 Fracture and Damage Process 103 8.2 Impactor Velocity, Deceleration, and Force 105 8.3 Impactor Indentation 108 8.4 Vertical Cuboid Deformation, Velocity, and Acceleration 110 8.5 Lateral Cuboid Deformation, Velocity, and Acceleration 113 8.6 Relative Cuboid Elongation in X- and Y-Direction 115 8.7 Path and Derivative of the Support Forces 118 8.8 Ultrasonic Pulse Velocity Measurements 120 8.9 Stimulation With the Impulse Hammer 121 8.10 Stimulation With the Steel Impactor 124 8.11 Overview Over Forces, Stresses, Strains, and Their Rates 128 8.12 Impulse and Momentum Conservation 133 8.13 Energy Conservation 135 8.14 Dimensioning of the Required Damping Layer Thickness Depending on the Loading Velocity 136 8.15 Conclusions 137 9 Cover Layer Variation in Cuboid Experiments 139 9.1 Fracture and Damage Process 139 9.2 Impactor Velocity, Deceleration, and Force 141 9.3 Impactor Indentation 144 9.4 Vertical Cuboid Deformation, Velocity, and Acceleration 145 9.5 Lateral Cuboid Deformation, Velocity, and Acceleration 147 9.6 Relative Cuboid Elongation in X- and Y-Direction 149 9.7 Path and Derivative of the Support Forces 150 9.8 Ultrasonic Pulse Velocity Measurements 152 9.9 Stimulation With the Impulse Hammer 153 9.10 Stimulation With the Steel Impactor 155 9.11 Overview Over Forces, Stresses, Strains, and Their Rates 157 9.12 Impulse and Momentum Conservation 162 9.13 Energy Conservation 163 9.14 Conclusions 164 10 Conclusions of the Cuboid Experiments 167 10.1 Main Findings 167 10.2 Most Relevant Sensor Positions and Measurements 167 10.2.1 Digital Image Correlation (DIC) of the Impactor 167 10.2.2 Lateral Acceleration 167 10.2.3 Digital Image Correlation (DIC) of the RC Cuboid 168 10.2.4 Ultrasonic Pulse Velocity (UPV) Measurements 168 10.2.5 Stimulation With the Impulse Hammer and the Steel Impactor 168 10.3 Suggested Improvements to the Setup 168 10.3.1 High-Speed Cameras (HSC) 168 10.3.2 Acceleration Sensors 169 10.3.3 Support Forces 169 10.3.4 Strain Gauges 169 10.3.5 Temperature Sensors 169 10.4 Comparison of the Material Behavior in Compressive SHB and Cuboid Experiments 169 10.4.1 Scattering of Measured Values 169 10.4.2 Failure Modes 170 10.4.3 Loading and Strain Rates 170 10.4.4 Influences of Inertia 170 10.4.5 Forces and Stresses 171 10.4.6 Energy Absorption 171 11 Summary and Conclusions 173 11.1 Compressive SHB Experiments 173 11.2 Tensile SHB Experiments 173 11.3 Damping Layer Variation in Cuboid Experiments 174 11.4 Cover Layer Variation in Cuboid Experiments 174 11.5 Conclusions 175 12 Outlook 177 12.1 Split Hopkinson Bar Testing 177 12.2 Strengthening Procedure 177 12.3 Large-Scale Impact Testing 177 12.4 Design 178 Bibliography 179 List of Figures 193 List of Tables 199 / Die vorliegende Arbeit beschäftigt sich mit der Verstärkung von Stahlbetonbauteilen gegen Impaktbeanspruchungen. Es wurden mineralisch gebundene Verstärkungsschichten entwickelt, die auf der impaktzugewandten Seite aufgebracht wurden und große Teile der Impaktenergie umwandelten, um somit die darunterliegenden Bauteile zu schützen. Die Verstärkungsschichten sind mehrlagig aufgebaut und die Materialien werden in Deck- und Dämpfungsschichten unterschieden. Dabei sind die Deckschichtmaterialien solche, die eine große Festigkeit und Steifigkeit besitzen. Sie werden direkt durch den Impaktor getroffen und sollen die Impaktlast auf einen größeren Bereich der darunterliegenden Dämpfungsschichten verteilen. Die Dämpfungsschichten sind weniger fest und steif und sollen die Impaktenergie in Reibungs-, Wärme- und innere Energie umwandeln. Als Dämpfungsschichtmaterialien wurden ein Beton mit Altgummizuschlägen, zwei unterschiedliche Leichtbetone und zwei Infraleichtbetone geprüft. Unter den geprüften Deckschichtmaterialien befanden sich ein Carbonbeton und unterschiedliche Mischungen mit Kurzfaserbetonen, die teilweise auch mit hybriden 3D Bewehrungsstrukturen bewehrt wurden. Zunächst wurden die Materialen unter dynamischer Druck- und Zugbelastung im Split-Hopkinson-Bar geprüft. Diese kleinteiligen Versuche sollen dem Verständnis des dynamischen Materialverhaltens dienen und bilden gleichzeitig die Grundlage für eine mögliche spätere numerische Analyse der Verstärkungsschichtmaterialien, die gleichzeitig die Variation der Materialeigenschaften von Verstärkungsschichten erlaubt. Anschließend wurden die unterschiedlichen Dämpfungs- und Deckschichtmaterialien in einem größeren Probenmaßstab untersucht. Die Probekörper, die unverstärkt sowie unterschiedlich verstärkt untersucht wurden, waren vollflächig gelagerte Stahlbetonquader. Zunächst wurde das Dämpfungsschichtmaterial variiert, um die Dämpfungsschicht zu finden, die am meisten Energie umwandeln und somit die Schädigung der Stahlbetonquader am effizientesten reduzieren kann. Diese wurde danach unter unterschiedlichen Deckschichten kombiniert, um das geeignetste Deckschichtmaterial zu ermitteln.:Abstract i Kurzfassung iii List of Symbols xv List of Abbreviations xix 1 Objectives, Working Program, and Structure 1 1.1 Motivation 1 1.2 Overall Objectives 1 1.3 Working Program 1 2 State of the Art and Theoretical Background 3 2.1 Impact on Structural Elements 3 2.1.1 Soft and Hard Impact 3 2.1.2 Failure Modes Under Hard Impact Conditions 3 2.1.3 Large-Scale Impact Experiments 4 2.1.4 Impact Protection Layers 4 2.2 Introduction of Impact Protection Principles 4 2.2.1 Impact Protection in Nature 4 2.2.2 Technical Impact Protection Examples 9 2.2.3 Summary of Impact Protection Principles and Usable Materials 14 2.3 Mineral-Bonded Damping Layer Materials 15 2.3.1 Waste Tire Rubber Concrete 15 2.3.2 All-Lightweight Aggregate Concrete 16 2.3.3 Infra-Lightweight Concrete 17 2.4 Mineral-Bonded Cover Layer Materials 18 2.4.1 Strain-Hardening Cementitous Composites 18 2.4.2 Textile Reinforced Concrete 19 2.4.3 Hybrid-Fiber Reinforced Concrete 19 2.5 Bond Between Different Strengthening Layers 20 3 Materials under Investigation 21 3.1 Specimen Preparation 21 3.2 Damping Layer Materials 22 3.2.1 Waste Tire Rubber Concrete (WTRC) 22 3.2.2 All-Lightweight Aggregate Concrete With Liapor Aggregates (ALWAC-L) 23 3.2.3 All-Lightweight Aggregate Concrete With Ulopor Aggregates (ALWAC-U) 23 3.2.4 Porous Lightweight Concrete (PLC) 23 3.2.5 Infra-Lightweight Concrete (ILC) 23 3.2.6 Comparison of the Damping Layer Materials 24 3.3 Cover Layer Materials 27 3.3.1 Pagel TF10 CARBOrefit With Carbon Textile Reinforcement (P-C) 27 3.3.2 Strain-Hardening Limestone Calcined Clay Cement (SHLC3) 27 3.3.3 Comparison of the Cover Layer Materials 28 3.4 Partially Loaded Areas 30 4 Methodology of Split Hopkinson Bar Experiments 35 4.1 Experimental Setup and Methodology 35 4.1.1 Compressive Split Hopkinson Bar 35 4.1.2 Tensile Split Hopkinson Bar 36 4.1.3 Instrumentation 39 4.2 Evaluation Process 39 4.2.1 Impedance 40 4.2.2 Raw Data Analysis, Filtering, and Time-Shifting of Pulses 41 4.2.3 Stresses and Strains 42 4.2.4 Deformations 50 4.2.5 Forces and Impulses 51 4.2.6 Energy Absorption 52 4.2.7 Fracture Energy 53 4.2.8 Averaging of the Results 54 5 Compressive Split Hopkinson Bar Experiments 57 5.1 Failure Modes 57 5.2 Stresses and Strains 58 5.2.1 Dynamic Compressive Strength 58 5.2.2 DIF 59 5.3 Deformations 60 5.4 Forces and Impulses 61 5.4.1 Relative Transmitted Force 61 5.4.2 Impulse Transmission 63 5.4.3 Reduction of the Pulse Inclination 64 5.5 Energy Absorption 64 5.6 Conclusions 66 6 Tensile Split Hopkinson Bar Experiments 69 6.1 Failure Modes 69 6.2 Stresses and Strains 70 6.2.1 Dynamic Tensile Strength 70 6.2.2 DIF 71 6.3 Deformations 72 6.4 Forces and Impulses 73 6.4.1 Relative Transmitted Force 73 6.4.2 Impulse Transmission 74 6.4.3 Reduction of the Pulse Inclination 75 6.5 Energy Absorption 75 6.6 Fracture Energy 77 6.7 Conclusions 78 7 Methodology of Cuboid Experiments 79 7.1 Experimental Program 79 7.1.1 Specimen Dimensions and Experimental Setup 79 7.1.2 Experimental Scheme 81 7.2 Measurements Taken During the Experiments 83 7.2.1 Light Barriers 84 7.2.2 Resistor 84 7.2.3 Strain Gauges 84 7.2.4 Laser Doppler Vibrometer 85 7.2.5 Accelerometers 85 7.2.6 Load Cells 85 7.2.7 High-Speed Cameras and DIC 85 7.3 Measurements Taken Before and After the Experiments 86 7.3.1 Impactor Indentation 86 7.3.2 Burst Mass 86 7.3.3 Ultrasonic Pulse Velocity Measurements 86 7.3.4 Stimulation 87 7.4 Evaluation Process 88 7.4.1 Fracture and Damage Process 88 7.4.2 Impactor Velocity, Deceleration, Force, Stress, and Stress Rate 88 7.4.3 Impactor Indentation, Strain, and Strain Rate 90 7.4.4 Vertical Cuboid Deformation, Velocity, and Acceleration 92 7.4.5 Lateral Cuboid Deformation, Velocity, and Acceleration 93 7.4.6 Relative Cuboid Elongation in X- and Y-Direction 93 7.4.7 Strain Measurements on the Reinforcement Bars 94 7.4.8 Path and Derivative of the Support Forces 95 7.4.9 Burst Mass 96 7.4.10 Ultrasonic Pulse Velocity Measurements 96 7.4.11 Stimulation 97 7.4.12 Impulse and Momentum Conservation 99 7.4.13 Energy Conservation 100 7.4.14 Estimation of the Eigenfrequency of the Cuboids 101 8 Damping Layer Variation in Cuboid Experiments 103 8.1 Fracture and Damage Process 103 8.2 Impactor Velocity, Deceleration, and Force 105 8.3 Impactor Indentation 108 8.4 Vertical Cuboid Deformation, Velocity, and Acceleration 110 8.5 Lateral Cuboid Deformation, Velocity, and Acceleration 113 8.6 Relative Cuboid Elongation in X- and Y-Direction 115 8.7 Path and Derivative of the Support Forces 118 8.8 Ultrasonic Pulse Velocity Measurements 120 8.9 Stimulation With the Impulse Hammer 121 8.10 Stimulation With the Steel Impactor 124 8.11 Overview Over Forces, Stresses, Strains, and Their Rates 128 8.12 Impulse and Momentum Conservation 133 8.13 Energy Conservation 135 8.14 Dimensioning of the Required Damping Layer Thickness Depending on the Loading Velocity 136 8.15 Conclusions 137 9 Cover Layer Variation in Cuboid Experiments 139 9.1 Fracture and Damage Process 139 9.2 Impactor Velocity, Deceleration, and Force 141 9.3 Impactor Indentation 144 9.4 Vertical Cuboid Deformation, Velocity, and Acceleration 145 9.5 Lateral Cuboid Deformation, Velocity, and Acceleration 147 9.6 Relative Cuboid Elongation in X- and Y-Direction 149 9.7 Path and Derivative of the Support Forces 150 9.8 Ultrasonic Pulse Velocity Measurements 152 9.9 Stimulation With the Impulse Hammer 153 9.10 Stimulation With the Steel Impactor 155 9.11 Overview Over Forces, Stresses, Strains, and Their Rates 157 9.12 Impulse and Momentum Conservation 162 9.13 Energy Conservation 163 9.14 Conclusions 164 10 Conclusions of the Cuboid Experiments 167 10.1 Main Findings 167 10.2 Most Relevant Sensor Positions and Measurements 167 10.2.1 Digital Image Correlation (DIC) of the Impactor 167 10.2.2 Lateral Acceleration 167 10.2.3 Digital Image Correlation (DIC) of the RC Cuboid 168 10.2.4 Ultrasonic Pulse Velocity (UPV) Measurements 168 10.2.5 Stimulation With the Impulse Hammer and the Steel Impactor 168 10.3 Suggested Improvements to the Setup 168 10.3.1 High-Speed Cameras (HSC) 168 10.3.2 Acceleration Sensors 169 10.3.3 Support Forces 169 10.3.4 Strain Gauges 169 10.3.5 Temperature Sensors 169 10.4 Comparison of the Material Behavior in Compressive SHB and Cuboid Experiments 169 10.4.1 Scattering of Measured Values 169 10.4.2 Failure Modes 170 10.4.3 Loading and Strain Rates 170 10.4.4 Influences of Inertia 170 10.4.5 Forces and Stresses 171 10.4.6 Energy Absorption 171 11 Summary and Conclusions 173 11.1 Compressive SHB Experiments 173 11.2 Tensile SHB Experiments 173 11.3 Damping Layer Variation in Cuboid Experiments 174 11.4 Cover Layer Variation in Cuboid Experiments 174 11.5 Conclusions 175 12 Outlook 177 12.1 Split Hopkinson Bar Testing 177 12.2 Strengthening Procedure 177 12.3 Large-Scale Impact Testing 177 12.4 Design 178 Bibliography 179 List of Figures 193 List of Tables 199