Reinforced concrete slab-column structures are widely used because of their practicality. However, this type of structures can be subject to punching-shear failure in the slab-column connections. Without shear reinforcement, the slab-column connection can undergo brittle punching failure, especially when the structure is subject to lateral loading in seismic zones. The shear bolts are a new type of transverse reinforcement developed for retrofit of existing structures against punching. This research focuses on how the shear bolts can improve the punching-shear capacity and ductility of the existing slab-column connections under vertical service and lateral seismic loads. A set of nine full-scale reinforced concrete slab-column connection specimens were tested under vertical service and cyclic loads. The vertical (gravity) load for each specimen was kept at a constant value throughout the testing. The cyclic lateral drift with increasing intensity was applied to the columns. The specimens were different in number of bolts, concrete strength, number of openings, and level of gravity punching load. Strains in flexural rebars in the slabs, crack widths, lateral loads, and displacements were obtained. The peak lateral load (moment) and its corresponding drift ratio, connection stiffness, crack width, and ductility were compared among different specimens. The testing results show that shear bolts can increase lateral peak load resisting capacity, lateral drift capacity at peak load, and ductility of the slab-column connections. Shear bolts also change the failure mode of the slab-column connections and increase the energy dissipation capacity. The thesis includes also research on the development of guidelines for shear bolt design for concrete slab retrofitting, including the punching shear design method of concrete slab (with shear bolts), dimensions of bolts, spacing, and influence of bolt layout patterns. Suggestions are given for construction of retrofitting method using shear bolts. Recommendations are also presented for future research.

In this thesis, we study the scattering problem of a vertically offset dielectric slab waveguide, using continuous radiation modes. The calculation of radiation modes of an arbitrarily layered waveguide has been thoroughly investigated in the literature. Most approaches were based on launching two incident waves: one from above and one from below, resulting in two transmitted waves and two reflected waves. Radiation modes were obtained by algebraic adjustments of each incident wave¡¦s amplitude and phase. These radiation modes formed standing waves in both the substrates and superstrates. This implies that walls are located an infinite distance far from the first and the last interfaces. In addition to physical conflicts of simultaneous existence of the incident wave and the walls, the derivation details are complicated and non-intuitive. In our thesis, with a given propagation constant for an arbitrarily layered dielectric waveguide, we propose an intuitive method to obtain two independent radiation mode solutions. We also construct a specific procedure to orthogonalize and normalize these two radiation modes. The second part of this thesis is focused on applying these radiation modes into a customized coupled transverse mode integral equation formulation (CTMIE), to the study of vertically offset slab waveguides. CTMIE requires two artificial boundaries placed in the substrate and superstrate. We choose to compute discretized radiation modes with the periodic boundary conditions. Under these circumstances, modes correspond to different spatial frequencies and thereby do not inter-couple. This means the matrix of the overlap integral between these two groups of modes (slightly vertically shifted) are block-diagonally dominated. The off-diagonal elements are two orders of magnitude smaller than the diagonal ones. As a result, when the two artificial boundaries are pushed towards infinity in the CTMIE formulation, we may obtain an exact inverse of the Greene¡¦s matrix without relying on numerical inversion.

Traditionally, destructive methods such as coring are used for the condition assessment of an existing concrete structure. Although these methods may yield valid data about the corresponding concrete section, they are quite expensive and time consuming. More important than these, destructive methods damage the structure being investigated and these points usually become focal points for further deterioration. For all these reasons, only a few samples can be collected from a structure and this results in a poor representation of the complete structure. The impact-echo technique is one of the most suitable non-destructive test methods that may be used on concrete for thickness determination or for investigation of possible delaminations in the internal parts of a concrete structure without damaging the surface. It has been observed that reliable results can be obtained quickly. Unlike pulse-echo tests which are commonly used on steel, testing a heterogeneous material like concrete requires the use of low frequency sound waves as in impact-echo, in order to mitigate the effects of paste-aggregate interfaces or small air voids. This method may be used to locate internal cracks or large air voids existing in concrete. It is known that impact-echo has been used successfully on structures with varying geometries and various purposes such as evaluation of concrete pavements, retaining walls and other reinforced concrete sections. Besides the investigation of the internal state, it may also be used when the other side of the section cannot be reached, as in the case of concrete pavements, in order to find the thickness of the section. This is especially important for quality control and for cost calculations. Research conducted in this thesis study was concentrated on the thickness determination of existing concrete pavement sections, produced in the laboratory with dimensions of 1500 x 2000 mm four and varying thicknesses, and the accuracy associated with these results. In order to correctly determine the sensitivity, several other parameters were investigated and optimum ranges were determined for these to be used while on a field test. Among these factors were the steel impactor size, accuracy related to the data acquisition, distance between the impact point and the transducer and the location of the test point. Finally, the accuracy of the impact-echo method for concrete pavement applications was studied. By observing the large number of data points collected, it was found out that an average error of 1.5% exists for a single impact-echo reading regardless of section thickness, but this value reduces to 0.6% when the average of all test results is used while determining pavement thickness. Results of this study show that the impact-echo technique is reliable and may be used with success for the thickness determination of concrete pavements and for locating internal voids.

The theoretical stability analysis of mold level control system for slab continuous casting machine is presented in this thesis. In the procedure of analyzing the stability of the mold level control system, the PLC program written for the control system is studied first in order to obtain the mathematical model of a PID controller. Then the mathematical models of servo-amplifier, servo-valve, electro hydraulic system to the output of mold level are established. A simulative control system using Matlab software is constructed in accordance with these mathematical models so that not only the results of stability analysis can be verified but also the dynamic response of controlled system can be studied. Finally, the effects of some potential disturbance on system¡¦s dynamics, stability, and control accuracy are also analyzed.

The objective of this study uses the plasticity theory of the slab method and the numerical analysis of the finite difference method to construct a mathematical model. And a computer program will be developed to evaluate the quality of the tubes formed by hydraulic expansion. Considering sticking and sliding modes, a mathematical model is proposed to predict the forming pressure needed to hydroform a circular tube into square and rectangular cross-sections and the thickness distribution of the product. In the sticking friction mode, it is assumed that the elements after contact with the die do not move or slide. Whereas, in the sliding friction mode, the element in contact with the die will continue to deform with the stress variation in the subsequent forming process. A series of FE simulations on tube expansion by a commercial FE code¡§DEFORM¡¨have been carried out. In addition, the experiment employing aluminum alloy AA 6063 that has been annealed to proceed the hydraulic expansion experiment. The comparisons between analysis and the result of forming pressure, corner radius and thickness distribution by experiment are verified the validity of this mathematical model. The effects of the forming parameters such as the die geometry, the material property of the tube, friction coefficient between the die and tube, etc., upon the expansion results, such as the forming pressure, corner radius, the tube contact distance with the die, thickness distribution after expansion, etc., are systematically discussed.

Engineers proposed the idea that arching action present may be present in bridge deck cantilever slab overhangs, stiffened along their longitudinal free edge via a traffic barrier, subjected to a wheel load. The experimental research program consisted of the design, construction, and static as well as fatigue destructive testing of a full-scale innovative bridge deck slab complete with two traffic barrier walls. The observed experimental data provided extremely interesting findings that indicated a very strong presence of arching action in edge-stiffened cantilever slab overhangs subjected to static and fatigue wheel loads. Deflection profiles indicated curvatures that contradict classical flexural behavior. Large tensile strain magnitudes on the bottom reinforcing mat in all cantilever test locations as well as cracking patterns dictate behavior typical to arching action. Top transverse strains measured did not agree with flexural theory and patterns confirmed earlier research finding that the quantity of top transverse reinforcement may be reduced. Compressive strains measured on the top surface of the cantilever contradicted flexural theory and confirmed the presence of arching action. Punching shear modes of failure observed in all test locations also strengthened the argument for the presence of arching action. Theoretical and analytical modeling techniques were able to validate and confirm the experimental test results. Based on experimental research findings and analytical modeling researchers were able to confirm a major presence of arching action in edge-stiffened cantilever slab overhangs subjected to static and fatigue wheel loads. Recommendations include a proposed reduction in top transverse reinforcement provided in the adjacent internal panel due to the presence arching action that could contribute to a significant initial capital cost savings. Based on the research findings, the report also suggests potential provisions to design codes that take into account the presence of arching action. Further research and theoretical modeling is still required to better understand the presence of arching action in edge-stiffened cantilever slab overhangs. Additional testing and a demonstration project complete with civionics and structural health monitoring will aid engineers in the implementation of the break-through findings highlighted in this study. / February 2016

The objective of this research program is to further evaluate the performance and constructability of reinforced concrete (RC) column-steel beam-slab systems (RCS) for use in low- to mid-rise space frame buildings located in regions of high wind loads and/or moderate seismicity. To better understand these systems, two full scale RCS cruciform specimens were tested under bidirectional quasi-static reversed cyclic loading. The experimental portion of this research program included the construction and testing of two full-scale cruciform specimens with identical overall dimensions but with different joint detailing. The two joint details evaluated were joint cover plates and face bearing plates with localized transverse ties. The construction process was recorded in detail and related to actual field construction practices. The specimens were tested experimentally in quasi-static reversed cyclic loading in both orthogonal loading directions while a constant axial force was applied to the column, to simulate the wind loads in a subassembly of a prototype building. To compliment the experimental work, nonlinear analyses were performed to evaluate the specimen strength and hysteretic degradation parameters for RCS systems. In addition, current recommendations in the literature on the design of RCS joints were used to estimate specimen joint strength and were compared with the experimental findings.

Husgrunder stödjer hela hus och ska vara stadiga nog för att ta upp husets vikt och bära byggnaden i många år utan att drabbas av problem orsakade av bland annat fukt och tjäle. Det finns tre grundkonstruktionstyper som tas upp i detta arbete. Dessa är: platta på mark, krypgrund och plintgrund. Syftet med arbetet är att undersöka konstruktion och funktion för de tre grundkonstruktionerna. Arbetet redovisar också vilka grunder som är förekommande vid nybyggnation av småhus i Örebro län, samt hur olika aktörer inom byggbranschen motiverar sina val med avseende på risken för fuktrelaterade problem. Inom detta examensarbete redovisas resultat från intervjuer med ett antal olika byggnadsaktörer som bygger med olika typer av grundkonstruktioner. Information har samlats in genom intervjuer med sakkunniga samt egen teorifördjupning i litteratur för grundkonstruktioner. Utifrån syftet med arbetet har teorin och resultaten från intervjuerna sammanställts. Platta på mark med underliggande isolering är den grundkonstruktion som framförallt väljs vid val av grundkonstruktion för nybyggnationer av småhus i Örebro län. Aktörerna upplever att denna konstruktion har många fördelar i jämförelse med de andra konstruktionerna: krypgrund och plintgrund. / Foundations support entire houses and are required to be adequately well-built to carry a building’s mass for many years without facing problems due to environmental impacts such as moisture and frost. This work covers three basic types of foundations; concrete slab, crawl space and block foundation. The aim of this work is to investigate the construction methods of the foundations mentioned above, which are used within the construction of single-family homes in the city of Örebro, Sweden. Additionally, the basis of selection of these foundations by various construction companies in respect to risk of moisture-related problems is examined. Information about the foundations is collected from scholarly literature as well as qualitative interviews with seven construction companies’ experts. Ultimately, this study found that concrete slab with underlying insulation is more commonly used within the construction of single-family homes in Örebro than the other alternatives. Operators find that this foundation has many advantages in comparison with the other foundation techniques.

This research investigates prefabricated light-gauge steel and concrete panels using reliable and commercially viable shear connectors. An analytical and experimental investigation was undertaken to study the flexural behaviour of light-gauge steel and concrete composite panels under uniform pressure. Normalweight and lightweight concrete panels were fabricated by embedding 16-gauge 41 mm x 203 mm steel channel sections (running parallel to each other) to a depth of 38 mm into a 64 mm thick concrete slab. Push-out tests were also conducted to evaluate the efficiency of three types of shear connection mechanism; natural surface bonding, predrilled holes, and punched holes. Only two types of shear connectors (predrilled holes and punched holes) were used in the full-scale panel specimens. Results show that the predrilled holes and punched holes provide full shear transfer between the steel and concrete. The ultimate load carrying capacity of the lightweight concrete panels exhibited similar behaviour to the normalweight concrete panels. All the panels exhibited good load carrying capacity and ductility, and satisfied the serviceability limit state of deflection. Thus, the proposed panels present a potential for a commercially viable composite floor system for building construction utilizing a maximum span of 2330 mm.

Šiame darbe projektuojamas statybinių medžiagų centras, Šiauliuose, Metalistų gatvėje, su prekybinėmis patalpomis, sandėliu bei buitinėmis – adminitracinėmis patalpomis. Aprašomas sklypo planas, pastato patalpų išplanavimas, kontrukciniai sprendimai bei inžineriniai tinklai. Suprojektuota 18 m metalinė santvara SN-18, parinkta 5,6 m ilgio dvitėjo profilio sija SI-5.6, suprojektuota 5,94 m ilgio gelžbetoninė perdangos plokštė PP 594-120-22. Sudaryta perdangų montavimo technologin÷ kortelė, perdangų montavimui parinktas automobilinis kranas. Sudaryti pagrindinių konstrukcijų darbų kiekių žiniaraščiai ir pagal juos sudaryta lokalinė sąmata. Paskaičiuoti administracinių – buitinių patalpų šilumos laidumo koeficientai, šilumos nuostoliai. Pagal šiuos apskaičiuotus duomenis parinkti šildymo prietaisai. / In this work, there is a centre of building materials that is being designed in Siauliai, Metalistu Street. It consists of trading rooms, warehouse and domestic – administrative rooms. Description of the plan of the plot, layout of rooms, construction decisions and engineering networks. Designed 18 m metallic truss SN-18, selected 5,6 m length HEA-beam SI-5.6, designed 5,94 m length reinforced floor slab PP 594-120-22. Made out of floors installation technological card, for floors installing selected truck crane. Formed sheets of quantity of main constructial workings and accordingly formed local estimation. calculated administrative – domestic rooms heat-transferring coefficient, heat ranges. According to the calculated data, heating devices were chosen.