Reinforced concrete poles are commonly used as street lighting and electrical transmission poles. Typical concrete lighting poles experience very little load due to torsion. The governing design loads are typically bending moments as a result of wind on the arms, fixtures, and the pole itself. The Canadian pole standard, CSA A14-07 relates the helical reinforcing to the torsion capacity of concrete poles. This issue and the spacing of the helical reinforcing elements are investigated. Based on the ultimate transverse loading classification system in the Canadian standard, the code provides a table with empirically derived minimum helical reinforcing amounts that vary depending on: 1) the pole class and 2) distance from the tip of the pole. Research into the minimum helical reinforcing requirements in the Canadian code has determined that the values were chosen empirically based on manufacturer’s testing. The CSA standard recommends two methods for the placement of the helical reinforcing: either all the required helical reinforcing is wound in one direction or an overlapping system is used where half of the required reinforcing is wound in each direction. From a production standpoint, the process of placing and tying this helical steel is time consuming and an improved method of reinforcement is desirable. Whether the double helix method of placement produces stronger poles in torsion than the single helix method is unknown. The objectives of the research are to analyze the Canadian code (CSA A14-07) requirements for minimum helical reinforcement and determine if the Canadian requirements are adequate. The helical reinforcement spacing requirements and the effect of spacing and direction of the helical reinforcing on the torsional capacity of a pole is also analyzed. Double helix and single helix reinforcement methods are compared to determine if there is a difference between the two methods of reinforcement. The Canadian pole standard (CSA A14-07) is analyzed and compared to the American and German standards. It was determined that the complex Canadian code provides more conservative spacing requirements than the American and German codes however the spacing requirements are based on empirical results alone. The rationale behind the Canadian code requirements is unknown. A testing program was developed to analyze the spacing requirements in the CSA A14-07 code. Fourteen specimens were produced with different helical reinforcing amounts: no reinforcement, single and double helical spaced CSA A14-07 designed reinforcement, and single helical specimens with twice the designed spacing values. Two specimens were produced based on the single helical reinforcement spacing. One specimen was produced with helical reinforcement wound in the clockwise direction and another with helical reinforcement in the counter clockwise direction. All specimens were tested under a counter clockwise torsional load. The clockwise specimens demonstrated the response of prestressed concrete poles with effective helical reinforcement whereas the counter clockwise reinforced specimens represented theoretically ineffective reinforcement. Two tip sizes were produced and tested: 165 mm and 210 mm. A sudden, brittle failure was noted for all specimens tested. The helical reinforcement provided no post-cracking ductility. It was determined that the spacing and direction of the helical reinforcement had little effect on the torsional capacity of the pole. Variable and scattered test results were observed. Predictions of the cracking torque based on the ACI 318-05, CSA A23.3-04 and Eurocode 2 all proved to be unconservative. Strut and tie modelling of the prestressing transfer zone suggested that the spacing of the helical steel be 40 mm for the 165 mm specimens and 53 mm for the 210 mm specimens. Based on the results of the strut and tie modelling, it is likely that the variability and scatter in the test results is due to pre-cracking of the specimens. All the 165 mm specimens and the large spaced 210 mm specimens were inadequately reinforced in the transfer zone. The degree of pre-cracking in the specimen likely causes the torsional capacity of the pole to vary. The strut and tie model results suggest that the requirements of the Canadian code can be simplified and rationalized. Similar to the American spacing requirements of 25 mm in the prestressing transfer zone, a spacing of 30 mm to 50 mm is recommended dependent on the pole tip size. Proper concrete mixes, adequate concrete strengths, prestressing levels, and wall thickness should be emphasized in the torsional CSA A14-07 design requirements since all have a large impact on the torsional capacity of prestressed concrete poles. Recommendations and future work are suggested to conclusively determine if direction and spacing have an effect on torsional capacity or to determine the factors causing the scatter in the results. The performance of prestressed concrete poles reinforced using the suggestions presented should also be further investigated. Improving the ability to predict the cracking torque based on the codes or reducing the scatter in the test results should also be studied.

During the last decades, batch distillation is preferably used with an increasing demand over continuous one, to separate fine chemicals in chemical and petroleum industries, due to its advantages like, flexibility and high product purity. Consequently, packed distillation columns, with newly generated packing materials, are advantageous compared to plate columns because of their smaller holdups, resistivity to corrosive materials and their higher separation efficiencies. Also, in many industrial applications, mathematical models of distillation systems are frequently used in order to design effective control systems, to train operating personnel and to handle fault diagnostics. Thus, the main objective of this study is to develop a mathematical model for a multicomponent batch distillation column, which is used to separate mixtures at low operating pressures, packed with random packing materials. In multicomponent batch packed distillation, operation with optimum reflux ratio profile is important for efficiency to maximize the amount of the distillate with a specified concentration, for a given time. Therefore, it is also aimed to find the optimum reflux ratio profile for the multicomponent batch packed distillation column. A simulation algorithm is written with the aid of MATLAB and FORTRAN programming languages by taking into account pressure drop and variation of physical properties. The selected incremental bed height, &amp / #916 / z, to be used in the simulation program has an effect on the accuracy of the results. This is analyzed and the optimal incremental height is found to be 3.5 cm for a 1.5m bed height. The change in distillate compositions with a given constant reflux ratio is found to be similar with those of previous studies. The simulation code is also used to obtain responses in distillate compositions for different reflux ratios, condenser holdups and reboiler duties and compared with similar studies found from literature and found to be adequate. Finally, experiments are conducted to verify simulation algorithm by using a lab-scale packed distillation column for the separation of a polar mixture of ethanol and water. It is observed that, there is a good agreement between the experimental and simulation results. After the verification of dynamic model, optimum operation policy to maximize product amount is investigated numerically by using capacity factor approach. The column is operated with and without recycling of the holdups of the slop cut tanks, in order to examine the effect of recycling on capacity factor, CAP. It is observed that, recycling of the molar holdups of the slop cut tanks is resulted in a 28% increase in the separation efficiency.

The use of composite steel-concrete columns and beam-columns in many structural systems is increasing globally due to the intrinsic synergy when these materials are designed and detailed together properly. However, limited test data are available to justify the structural system response factors and comprehensive design equations in current design specifications. This research, through the testing of 18 full-scale, slender concrete-filled steel tube (CFT) beam-columns, attempts to address the latter need. The circular and rectangular CFT specimens tested for this research are by far the longest and the most slender full-scale CFT members tested worldwide. These CFT specimens were subjected to a complex load protocol that includes pure compression, uniaxial and biaxial bending combined with compression, pure torsion, and torsion combined with compression. In addition, data from the hydrostatic pressure on the steel tubes due to the fresh concrete at casting was evaluated. The single most important contribution of this research is the clarification of the interaction between strength and stability in slender composite concrete-filled columns and beam-columns. Parallel to the experimental study, advanced computational analyses were carried out to calibrate material and element models that characterize the salient features of the observed CFT response, such as steel local buckling and residual stresses, concrete confinement, stability effects, strength, and stiffness degradation, among others. Based on the observed behavior, simplified guidelines for the computation of the strength and stiffness parameters for CFT columns and beam-columns are proposed for design purposes.

The objective of this research is to evaluate the stiffness and strength demands on flange braces in metal building systems. This objective is accomplished by a targeted study of the effects of various attributes of metal building systems not fully addressed in existing bracing design procedures. Special emphasis is placed on attributes such as unequal brace spacing and stiffness, end brace point flexibility, nonprismatic member geometry, special requirements at knee joints and the specific configuration of combined girt/purlin, flange diagonal, diaphragm and X bracing systems used in metal building construction. A sub-objective of the research is the demonstration of how virtual test simulation via full nonlinear finite element analysis may be applied to solve a structural engineering research problem that would be difficult to address by any other means. When conducted properly, virtual test simulation can serve as a valuable companion to experimental testing since attributes such as residual stresses and critical geometric imperfections can be controlled precisely and with relative ease in virtual test simulation. Both highly simplified and more complex but relatively rigorous procedures are considered, with the ultimate goal being improved economy and safety of flange stability bracing in metal buildings.

The effectiveness of a new structural material, namely textilereinforced mortar (TRM), was investigated experimentally in this study as a means of confining old-type reinforced concrete columns with limited capacity due to bar buckling or due to bond failure at lap splice regions. Comparisons with equal stiffness and strength fiber-reinforced polymer (FRP) jackets allow for the evaluation of the effectiveness of TRM versus FRP. Tests were carried out on full scale non-seismically detailed RC columns subjected to cyclic uniaxial flexure under constant axial load. Thirteen cantilever-type specimens with either continuous longitudinal reinforcement (smooth or deformed) or lap splicing of longitudinal bars at the floor level were constructed and tested. Experimental results indicated that TRM jacketing is quite effective as a means of increasing the cyclic deformation capacity of old-type RC columns with poor detailing, by delaying bar buckling and by preventing splitting bond failures in columns with lap spliced bars. Compared with their FRP counterparts, TRM jackets used in this study were found to be equally effective in terms of increasing both the strength and deformation capacity of the retrofitted columns. From the response of specimens tested in this study, it can be concluded that TRM jacketing is an extremely promising solution for the confinement of reinforced concrete columns, including poorly detailed ones with or without lap splices in seismic regions.

<p>The thesis is dealing with mixing processes havingapplication to ground improvement by deep mixing. The mainobjectives of the thesis is to make a contribution to knowledgeof the basic mechanisms in mixing binding agents into soil andimprove the knowledge concerning factors that influence theuniformity of stabilised soil.</p><p>A great part of the work consists of a literature surveywith particular emphasis on literature on the processindustries. This review forms a basis for a profounddescription and discussion of the mixing process and factorsaffecting the process in connection with deep mixingmethods.</p><p>The thesis presents a method for a simple field test for thestudy of influential factors in the mixing process. A number offactors in the installation process of lime-cement columns havebeen studied in two field tests using statistical multifactorexperiment design. The effects of retrieval rate, number ofmixing blades, rotation speed, air pressure in the storagetank, and diameter of the binder outlet on the stabilisationeffect and the coefficient of variation determined byhand-operated penetrometer tests for excavated lime-cementcolumns, were studied.</p><p>The literature review, the description of the mixingprocess, and the results from the field tests provide a morebalanced picture of the mixing process and are expected to beuseful in connection to ground improvement projects and thedevelopment of mixing equipments.</p><p>The concept of sufficient mixture quality, i.e. theinteraction between the mixing process and the mechanicalsystem, is discussed in the last section. By means ofgeostatistical methods, the analysis considers thevolume-variability relationship with reference to strengthproperties. According to the analysis, the design values forstrength properties depends on the mechanical system, the scaleof scrutiny, the spatial correlation structure, and the conceptof safety, i.e. the concept of sufficient mixture quality isproblem specific.</p><p><b>Key words:</b>Deep Mixing, Lime cement columns, Mixingmechanisms, Mixture quality, Field test, ANOVA, Variancereduction.</p>

Thesis (Ph. D.)--Lehigh University, 2003. / In three parts. Includes vita. Includes bibliographical references (leaves 770-775).

This paper explains the relationship and different arguments concerning freedom of speech. It uses Swedish newspaper columns, such as editorial pages, as its main source. The paper is mainly based upon the work of John Stuart Mill and his book On Freedom and Thomas Hobbes work Leviathan. The main focus is to see if there’s any connection between the Swedish newspapers and the theories which in itself is based upon the two works. The method that was used throughout this thesis was a content analysis which means that all of the newspaper articles and columns were analyzed and put into three different categories with category number one being based upon John Stuart Mill and his ideas, and number three being based upon Thomas Hobbes. Number two worked as a middle way and combined both of the theories. In those separate categories they were read and analyzed after arguments. Arguments that were often recurring were the main focus and were also the ones that were used for the final conclusion. The conclusion was based on the articles and the output was that the majority of the articles actually went on the same line as John Stuart Mill and that a few would like to see some kind of restriction on freedom of speech.

Slender structures are elegant aesthetically. The insufficiency in knowledge of the real resistance to buckling of very slender reinforced concrete columns leads to an exaggeration of the sizes of the columns. _The examples of concrete compression members cited and constructed in Industry on a global basis suggest that very slender columns have inherent safety both from the point of view of the ultimate strength and stability. The strengths of columns given. by the British codes would seem to be exceeded by many of the long slender reinforced concrete columns and struts which have been used Internationally. Both the theoretical and the experimental short term investigations have been carried out to establish the behaviour of hinged, very slender reinforced concrete columns at various stages'of axial loading. Forty three very slender reinforced concrete columns of two different square cross sections with two sizes of longitudinal reinforcements with lateral ties were cast. Slenderness rates, L A, were varied from 30 to 79. Special factors were obtained to relate the actual modulus of elasticity of concrete in columns at buckling failure to a knowledge of the initial modulus of elasticity of concrete in control cylinder specimens. Both theoretical and experimental graphs of load against moment, made dimensionless for critical sections of columns have been obtained. Dimensionless load-moment interaction diagrams using material failure as the criterion have been superimposed on these graphs to show considerable inherent material strength of the tested columns near buckling collapse failures. A theory using the fundamental approach has, been developed to predict the deflected shape and moments along the, heights of the columns at various stages of loading. The proposed theory predicts with good correlations the experimental deflections and moments of any loading stages of the columns. The theory has been used to obtain the required variables, to arrive at the initial predicted design loads of the investigated columns. Good correlations of the moments derived from observed strains have also been obtained. The developed theory predicts satisfactorily the buckling collapse loads of the columns. Although the theory has been derived for axially I loaded very slender reinforced concrete-columns, it seems to accept satisfactorily eccentricities of up to about 10 mm. This was confirmed after extensive comparisons of the theoretical buckling collapse loads with the applicable tests of other authors. Creep In the columns investigated was discovered to be one of the major factors for serious consideration. This was conclusively revealed from the observations on the last two very long term creep tests on columns. The actual safe sustained loads for these very slender columns of slenderness ratios, L/H, between 40 and 79 seem to be between 33% and 19% of the short term buckling collapse loads. The reduced modulus approach to predict the safe long term sustained loads seems to give reasonable values for L/H ratios of 40 and 50. The recommendations given for the proposed design of very slender reinforced concrete columns seem to be adequate and simple to use in practice. They are further simplified by the derivation of two equations for the reduction factors, R, for the slenderness ratios between 36 and 40 and between 40 and 79 respectively. The investigation has proved that very slender reinforced concrete columns are very dangerous structural members, as they tend to have violent buckling failures. Nevertheless, It must be prudent not to design against disaster at any cost. This Investigation seemed to have enhanced considerably knowledge of the design of very slender reinforced concrete columns.

Terrorism has been an international threat to high occupancy civilian structures, government buildings, and military installations for many years. Statistical data from past terrorist attacks show that transportation infrastructure has been widely targeted, and a bombing of an ordinary highway bridge is a realistic scenario. Recent threats to bridges in the U.S. confirm this concern and have caught the attention of the bridge engineering community. Given that many ordinary highway bridges in the United States support critical emergency evacuation routes, military transportation plans, and vital economic corridors, the loss of a key bridge could result in severe national security, economic, and socioeconomic consequences. Therefore, in this research, a simplified procedure is developed to predict blast loads on bridge columns, and an understanding of the mechanisms that cause damage and ultimately failure of blast-loaded reinforced concrete bridge columns is advanced. To that end, computational fluid dynamics models are constructed and validated using experimental data. These numerical models are used to characterize the structural loads experienced by square and circular bridge columns subjected to blast loads, which is followed by the formulation of a simplified load prediction procedure. Additionally, nonlinear, three-dimensional, dynamic finite element models of blast-loaded reinforced concrete bridge columns are developed and validated using qualitative and quantitative data from recent experimental tests. The results of these analyses illustrate the fact that circular columns cannot be assumed to experience less base shear demand than a square column simply because they experience less net resultant impulse. Furthermore, the column response models developed in this research are used to identify and explain the mechanisms that lead to the spalling of side cover concrete off blast-loaded reinforced concrete members observed in recent experimental tests. Therefore, the results of this research advance the understanding of the structural loads on and the resulting response of reinforced concrete bridge columns subjected to blast loads, and as such these contributions to the structural engineering community enhance the security of the U.S. transportation infrastructure. / text