In the assumptions, it was indicated that a modification in the method of analysis would allow taking into account the variation in pressure. This could be done by assuming that the internal pressure P used in the analysis was the pressure after deformation. During deformation, the mass of the enclosed gas remains constant. Thus, knowing the initial and final volumes and the final pressure, the initial internal pressure could be determined using the appropriate gas law. / Master of Science

Three models are presented which predict frequencies and mode shapes of transverse vibration for a continuous prismatic Bernoulli-Euler beam on elastic supports, subjected to a compressive axial load. The first model, which approximates support stiffnesses by an equivalent elastic foundation, is found to be inaccurate for wave lengths close to the support spacing. A discrete mass model is formulated which accounts for axial load by stability functions which modify the element stiffness matrices. A continuous model is formulated which yields an exact solution for Bernoulli-Euler beam theory. The frequencies predicted by the discrete mass model and continuous model are in excellent agreement. A method of predicting axial compressive load and support stiffness based on measured frequency and phase data is presented which can be used for either the discrete mass model or the continuous model. A frequency reduction factor is derived which accounts for the effects of shear deformation and rotatory inertia. Tests are performed on an eight span beam with compressive axial load. Test results show that the models accurately predict frequencies and mode shapes of vibration. Results indicate that the method formulated can be used to determine compressive axial load and support stiffness. / Master of Science

Inflated fabric is being considered as new structural material at the present time. It can be used in certain applications with the advantage of reducing the weight of structures, it is adaptable as an architectural element of construction; moreover, it may be developed to be one of the most economical, and simple structural materials in the future. A number of experimental investigations of these inflated fabric structures has been studied by research units of airship and fabric companies. However, due to the difficulties of solving such problems by analysis, there is still lack of theoretical methods, even approximate solutions. The purpose of this thesis is to investigate theoretical analysis for finding the relation between the applied load and the deflections, stresses, and also the end shortening of an inflated cylindrical fabric envelope subjected to axial compression, by the energy method. A cylindrical shape is selected because sphere and cylinder are considered more general in use and more easily to be treated than any other geometrical shapes. Also, for the sake of simplicity, a constant internal pressure is assumed in the analysis. The use or large deflection theory for finding the critical buckling loading of thin shells was first advanced by Von Karman and Tsien (reference 6 and 7). Based on their conception; numerous studies concerning the buckling strength under various loadings have been investigated by others subsequently. The strain-displacement relation in their papers is expressed in the following form including terms up to second order: ε_x= ∂u/∂x+(½)(∂w/∂x)² ε_x= ∂v/∂y+(½)(∂w/∂y)²-(w/R) In this thesis, although the idea is applied to develop an analysis by the energy method, the strain-displacement relation is expressed in a different way which will be shown in the following sections. Generally, in avoiding the mathematical difficulty of solving the differential equations obtained from the energy expression, most boundary-value problems in the theory of elasticity may be solved by assuming a solution in the form of a series which satisfies the boundary conditions, then minimizing the energy expression to determine the values of unknown parameters in the assumed solution. In this thesis, instead of using the variational method mentioned above, a graphical method for solving the differential equations is presented. However, owing to the fact that not all of the boundary conditions are specified at one point, the final results have to be obtained. by trial and error. / Master of Science

When a rope quickly transfers from a slack state to a taut state, a snapping action occurs and produces a large tensile force which is known as a snap load. Energy is dissipated during this snap load, and it is proposed to use synthetic fiber ropes as a type of passive earthquake damper in order to take advantage of this phenomenon. This thesis is the second phase of a multi-stage research project whose goal is to investigate and develop what will be known as Snapping-Cable Energy Dissipators (SCEDs). The experimental data that was collected in the Master'­s Thesis of Nicholas Pearson was organized and analyzed as a part of this research in order to evaluate the behavior of the ropes during the snapping action. Additional tests were also conducted for this project under more controlled conditions in order to better understand how the ropes change throughout a sequence of similar snap loadings and also to determine the amount of energy that is dissipated. The data from both projects was then used as input parameters for a mathematical model that was developed to characterize the behavior of the ropes during a snap load. This model will be utilized in subsequent research involving the finite element analysis of the seismic response of structural frames containing SCEDs. / Master of Science

Eight roughness configurations in Clemson boundary layer wind tunnel are presented. For these configurations, flow parameters such as turbulent intensities, integral length scales, large- and small- scale turbulence, and spectra of velocity components of the wind are obtained and studied to the simulated turbulence. At the same time, new analyzing tools, orthogonal wavelet techniques, are applied to provide additional information in time domain. This makes it possible to study the intermittency event, one important characteristic associated with pressure peak activities in turbulence. Three parameters, scale energy, intermittency factor and intermittency energy are defined. Variation of these quantities as a result of different configuration is discussed. Finally, the corresponding variations in measured pressure peaks in relation with the variations of configuration as well as with the intermittency parameters are investigated. The work here is of important significance for future wind tunnel and field data comparison, and this could help to find the best simulation among all configurations. / Master of Science

This paper is an extension of various projects that the writer has been associated with at Chance Vought Aircraft, Incorporated.

Résumé : Afin de contribuer dans la réponse latérale des pieux sous sollicitations latérales et notamment prendre en compte des plusieurs paramètres en relation avec les pieux (matériau, diamètre, rigidité, inclinaison) et le sol (nature, rigidité), des analyses numériques en différences finies 2D et 3D ont été réalisées en considérant des pieux chargés latéralement et ancrés dans des sols sableux, argileux et même sableux-argileux. Des modèles numériques simulés avec les codes en différences finies FLAC pour l’analyse 2D et FLAC[indice supérieur 3D] pour l’analyse 3D ont été inspirés des modèles de pieux réduits et en vraie grandeur, faisant l’objet de publications. Des enregistrements du déplacement latéral ou/et de la capacité latérale ou/et du moment fléchissant des pieux considérés ont été pris lors de ces essais. Ces modèles numériques ont été validés à travers diverses comparaisons entre les mesures, les calculs de FLAC et/ou FLAC3D et dans des cas les calculs d’autres méthodes utilisées dans la pratique. Une comparaison entre l’analyse 2D et l’analyse 3D de la réponse latérale d’un pieu rigide chargé latéralement dans un sol cohérent, a été réalisée dans le but de connaître les limites de l’analyse 2D et la possibilité de corréler ses résultats à ceux de l’analyse 3D. L’influence de la charge verticale sur la réponse latérale (capacité latérale et moment fléchissant maximal) d’un pieu en béton, chargé latéralement dans des sols sableux et argileux, a été étudiée avec une analyse numérique 3D. Il a été démontré que pour le cas des sols sableux, la charge verticale n’a pas un effet considérable sur la réponse latérale des pieux soumis à des charges latérales. Par contre, la charge verticale conduit à une diminution significative de la capacité latérale des pieux dans des sols argileux. Il est également constaté que l'influence des charges verticales sur la réponse latérale du pieu installé dans une argile surconsolidée avec une résistance au cisaillement non drainée proportionnelle à la profondeur et un OCR variant de 1,5 à 4,0 est très différent de celle correspondante à une résistance au cisaillement non drainée constante quelle que soit la valeur d’OCR. Des analyses 3D ont été, également, effectuées pour étudier la réponse latérale de pieux inclinés et chargés latéralement. La capacité latérale des pieux inclinés dans les sols sableux est considérablement augmentée avec l’augmentation de la valeur de l’inclinaison du pieu correspondante à la direction opposée à la direction de la charge latérale, et la densité du sable. Mais lorsque la direction de l’inclinaison du pieu et la même que celle correspondante à la charge latérale, cette capacité latérale est légèrement à modérément augmentée tout dépendamment de la valeur et le signe de l'angle ainsi que de la densité du sable. L’influence de l’angle d’inclinaison associé avec la charge verticale sur la capacité latérale de pieux inclinés est aussi très importante pour les sols sableux. Pour les sols argileux, l'influence de l'angle d’inclinaison sur la capacité latérale dépend seulement de l'angle d’inclinaison. En effet, la capacité latérale est modérément augmentée. Par contre, L'effet combiné de l’angle et la charge verticale est assez important. // Abstract : This thesis pertains to numerical analyses conducted primarily to evaluate the lateral response of piles and the contribution of several parameters related to piles (e.g., material, diameter, stiffness, inclination) and the soil (e.g., type, rigidity). Numerical finite differences analysis in 2D and 3D have been performed modelizing laterally loaded piles in sandy, clayey, and even sandy-clayey soils. Numerical models, simulated with finite difference codes FLAC for analysis in 2D and FLAC[superscript 3D] for 3D analysis, were inspired from experimental laboratory and full scale models available in literature. Measurements of lateral deflection and/or lateral capacity and/or bending moment of tested piles were recorded during these tests. These numerical models have been validated through comparison between the various measurements, predictions with FLAC and/or FLAC3D and for some cases the calculations with other methods used in practice. Comparison between 2D and 3D analyses of the response of laterally loaded rigid piles in cohesive soils, was performed in order to investigate the 2D analysis limitations and the possibility of correlating the 2D results with those of 3D analysis. A series of 3D finite differences analyses is also conducted to evaluate the influence of vertical loads on the lateral response of pile foundations. Numerical results have shown that the lateral resistance of the piles does not appear to vary considerably with the vertical load in sandy soil especially at loosest stat. However, vertical load leads to a significant decrease in lateral capacity of piles in homogeneous and inhomogeneous clay layers. It is also found that the influence of vertical loads on the lateral response of pile installed in over-consolidated clay with undrained strength proportional to depth and different OCR in the range of 1.5 to 4.0 is quite different from that with constant undrained strength regardless the adopted OCR value. The 3D finite difference analyses have been, also, carried out to investigate the lateral response of battered piles. The lateral capacity of the battered piles in sandy soils is considerably increased when the value of pile inclination corresponding to the opposite direction of the lateral load increases and when the sand density increases. But in the case of pile inclination corresponding to the same direction of the lateral load, the lateral capacity is slightly increased regardless to the adopted value of batter angle and the sand density. In clayey soil, it was found that the influence of the batter angle on the lateral capacity of piles depends only on the batter angle and not on the clay rigidity. For the case of pile inclination corresponding to the opposite direction of the lateral load, the lateral capacity is moderately increased and for the other case of inclination, the effects are not significant. The influence of both batter angle and vertical load on lateral capacity of battered pile in clayey soils is moderately pronounced.

Reinforced Concrete Box Culverts (RCBCs) are an integral part of the national and international transportation infrastructure. The National Bridge Inventory Standards (NBIS) requires that all bridges, which include culverts with spans ≥ 20 ft. (6.1 m), be load rated for safe load carrying capacity in accordance with the AASHTO Manual for Bridge Evaluation (MBE). In Kentucky, the Transportation Cabinet manages more than 15,500 bridges, of which almost 1,400 are bridge size culverts. Of the 1241 bridge size RCBCs that were being evaluated in Kentucky between 2015 and 2018, 846 were 2-cell culverts (or 68%). The objective in this study is to evaluate 2-cell RCBCs using the finite element (FE) method and to propose dead load and live load demand equations that can be used to determine the capacity demand ratio (C/D) and the load rating. The results indicate that the maximum dead load forces (positive and negative moments, and shear) vary linearly with respect to an increase in fill height, while the variation is bi-linear for the maximum live load forces. The proposed equations are derived in terms of the clear span and fill height. The results also indicated that, for fill heights greater than 10 ft (3 m), the maximum live load positive bending moments are less than 10% of their dead load counterparts. The primary advantage of the proposed equations lies in their simple formulation when analyzing and designing 2-cell culverts, which in turn alleviates the need to conduct a detailed finite element analysis to determine the maximum forces in 2-cell RCBCs.

In the Middle East region and many countries in the world, older reinforced concrete (RC) columns are deemed to be weak in seismic resistance because of their low amount of reinforcement, low grades of concrete, and large spacing between the transverse reinforcement. The capacity of older RC columns that are also slender is further reduced due to the secondary moments. Appropriate retrofit techniques can improve the capacity and behavior of concrete members. In this study, externally bonded Carbon Fiber Reinforced Polymer (CFRP) retrofit technique was implemented to improve the behavior of RC columns tested under constant axial load and cyclic lateral load. The study included physical testing of five half-scale slender RC columns, with shear span to depth ratio of 7. Three specimens represented columns in a 2-story, and two specimens represented columns in a 4-story building. All specimens had identical cross sections, reinforcement detail, and concrete strength. Two specimens were control, two specimens were retrofit with CFRP in the lateral direction, and one specimen retrofit in the longitudinal and lateral directions. A computer model was created to predict the lateral load-displacement relations. The experimental results show improvement in the retrofit specimens in strength, ductility, and energy dissipation. The effect of retrofitting technique applied to two full-scale prototype RC buildings, a 2-story and a 4-story building located in two cities in Iraq, Baghdad, and Erbil, was determined using SAP2000.

Hidromazgų taurų būklę, ilgaamžiškumą lemia juos veikiantys poveikiai ir apkrovos, susidarantys veikiant klimato sąlygoms, agresyviai aplinkai bei kitiems įvairiems veiksniams. Tyrimų tikslas – įvertinti Lietuvos tvenkiniuose susidarančias ledo apkrovas ir jų įtaką taurų gelžbetoninėms konstrukcijoms. Šiam tikslui pasiekti buvo atlikta literatūros analizė, siekiant nustatyti ledo apkrovų tipus. 2007 – 2010 m. mokslinių ekspedicijų metu natūriniais tyrimais įvertinta 10 hidromazgų taurų gelžbetoninių konstrukcijų būklė pagal STR.1.12.03:2006. Remiantis literatūros ir natūrinių tyrimų rezultatų analize, nustatyta, kad hidromazgų taurų gelžbetoninės konstrukcijos labiausiai ardomos dėl ledo poveikio. Detalesniam tyrinėjimui parinkti 6 hidromazgų taurai, kurių pažaidos leidžia teigti, kad taurų paviršinis betoninis sluoksnis buvo suardytas veikiant ledo apkrovoms. Darbe ledo poveikis analizuotas vertinant: 1) judančiųjų ledo laukų poveikio jėgą atskirai stovinčiai atramai; 2) sustojusiojo ledo lauko, atsirėmusio į statinį ir veikiamo tėkmės ir vėjo, poveikio jėgą; 3) jėgą, susidarančią atramai prarėžiant ledokamšą; 4) jėgą susidarančią dėl ledokamšos atsirėmimo į statinį statmenai jo frontui; 5) jėgą, kuria atrama pjauna ledogrūdą. Nustatyta, kad tvenkinių ledo apkrovos labiausiai priklauso nuo tauro pločio – didėjant tauro pločiui bendruoju atveju ir ledo apkrovos didėja. / Technical state of hydroschemes, durability leads to them acting and the effects of load resulting from operation of weather conditions, aggressive environment, and other various factors. The aim of this work - to evaluate ice loads formed in the ponds of Lithuania and their impact on the reinforced concrete piers structures. The state of 10 reinforced concrete structures were evaluated by field investigations in accordance with STR.1.12.03: 2006 during the scientific expeditions in 2007 - 2010. On the basis of literature analysis and field investigations it was found that piers in hydroschemes suffer most from the ice impacts. More detailed investigation were selected 6 hydroschemes, in witcth were noticed the deterioration and it is posssibillity of concrete covering layer breaking due the impacts of ice loads. The ice loads were analyzed in this work: 1) the force of moving ice fields in contact with single pier; 2) the force of standing ice field, in the impact due wind and water drag forces; 3) the force from ice jam cutting by pier; 4) the force of ice jam in the perpendicular contact with stucture front, 5) the force, which is cutting support of the ice plug. It was found that the pond ice load is dependent on ice thickness - increases the overall thickness of the ice and the ice load increases. 5) the force from breakup jam cutting by pier.