A concrete beam is rarely subjected to pure torsion loading. However, in many design applications a beam is subjected to torsional loads in addition to bending and shear loading. The American Concrete Institute has developed a specification for the design of beams subjected to torsion. These specifications are found in ACI 318-83. In this research report, a computer program is presented, using these specifications, which will aid engineers in the design of reinforcement for concrete beams subjected to torsional loading. The provisions of the ACI 318-83 specification and their implementation into the computer program are presented. A sample problem is solved to compare the results of normal hand calculations to the results of the computer program. A listing of the computer program, written in Microsoft's GW BASIC, is provided. The designer enters information pertaining to the beams cross sectional properties, material properties and loading conditions. The program computes the concrete and reinforcement strength requirements and determines the amount of reinforcement required. The stirrup spacing and longitudinal reinforcement required are then determined and output to the designer.

Four rectangular, isotropically reinforced concrete slabs were constructed and loaded until collapse. All slabs were fixed on three edges with the fourth edge free. Three slabs contained openings at various locations while the fourth remained solid. The magnitudes of deflections were measured during loading and the final yield pattern and ultimate load were compared to those predicted by simple and advanced yield-line theory. An analytical computer program was developed and is presented for quick evaluation of the ultimate load and collapse mode of many types of uniformly loaded slabs by simple yield-line theory. Short specialized programs were also formulated to analyze the experimental slabs, considering the presence of simple corner levers and edge loads around the openings. This resulted in more accurate theoretical predictions and produced estimates of the percent difference between simple and advanced theory predictions. Analysis of the results showed excellent agreement between the advanced theory predictions and the experimental results. / M.S.

Generalized moment-curvature relations of reinforced concrete members for various cases have been developed. For a limited range of parameters, graphs have been prepared. With these graphs, and within the range of the parameters given, is possible to solve statically indeterminate structures of reinforced concrete with accuracy taking account of the effects of creep in the concrete. / Master of Science

The idea of tilt-up construction started in America in the early I900’s. In the beginning, this technique was mainly used on structures such as industrial warehouses and factories. However, recent developments and improvements in tilt-up construction technique and accessories have enabled this building method to be applied to many architecturally appealing offices and residential structures. There are many details the design-build team must consider to ensure the success of a tilt-up project. The floor slab must be designed for panel casting and to withstand the loading of the mobile crane which will be used to lift the panel. The crane capacity affects the panel size and weight. Proper curing and bondbreaker application are very important to reduce bonding and to ensure clear cleavage between concrete surfaces. Changing rigging configuration consumes expensive crane time and must be reduced to minimum possible. The availability of ground-release quick connect/disconnect tilt—up hardware improves workers safety and speeds up the erection process substantially. Although the stress analysis of simple wall panels during erection can be done by hand, panels with more complicated geometry or with openings, are more efficiently analysed with a computer. Many manufacturers have technical services to help in the design of insert layout so that the concrete will not be over stressed when the panel is tilted into position. After the panel is plumbed, it is braced temporarily before the final connection is made. For in-place loading there are now design aids available which ease the design process. When properly designed and built, tilt—up has proved to be a fast, efficient, and economical building construction technique. / Master of Science

During the initial phase of the investigation, four methods were selected for investigation from a review of literature sources,the specific ion probe, spectrophotometer, digital titrator, and Quantab titrator strips. The initial results from the laboratory testing procedure and evaluation based on cost, speed, accuracy, and level of expertise required indicated the specific ion probe was more suitable for use in the field when compared to the remaining methods selected. Effects of cement content and reaction temperature on the results obtained for the specific ion probe were also investigated. Results of the tests for the effects of cement content were somewhat inconclusive, but indicated more variability in the results as the amount of chloride present in the specimens increased. However, correlation between the increase in variability and i cement content was not indicated. The specific ion probe is affected by differences in temperature and the appropriate correction factor for the variation was determined. Field validation of the procedure was undertaken to substantiate the findings from the laboratory investigation. This was accomplished by subjecting the specific ion probe to testing specimens from bridges located in different exposure groups within the United States. Four bridges were tested for chloride content in Pennsylvania. Following this initial phase, three bridges were tested in Virginia, Florida, and Wisconsin respectively. An analysis of the variability in the effective diffusion constant for the bridges tested was also performed to determine any relationships which exist between different exposure groups and to determine effects of time. / Master of Science

As construction of the nation’s interstate highway system nears completion, the emphasis must now be focussed on the rehabilitation of many of the older sections of the system which have undergone damage or deterioration. The efficiency and effectiveness of the concrete removal operation will profoundly affect the outcome of the bridge rehabilitation. Pneumatic breakers, milling machines, and hydro-demolition are three concrete removal technologies utilized to remove concrete that has experienced various levels of damage or deterioration. A general examination of the three technologies is presented in the following five areas: the equipment, the work, production, cost, and quality. The information was primarily obtained through interviews and discussions with persons involved in bridge rehabilitation: contractors, State Highway Agency personnel, and equipment manufacturers and distributors. It is anticipated that the information presented will enable persons involved in the bridge rehabilitation industry to more effectively utilize the technologies discussed. / Master of Science

No description available.

Thesis (MEng)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: The construction industry is a competitive market and contractors need to keep up-to-date with new construction methods and technologies. Project teams in South Africa are required to make decisions during the early stages of construction projects. These decisions often need to be made in a short time period, and include the decision between various construction methods, such as the decision between in-situ concrete construction and hybrid concrete construction. Hybrid concrete construction is a combination of pre-fabricated concrete and cast in-situ concrete to obtain the supreme benefits of their different construction qualities. This method of construction is ultimately used to achieve faster, and occasionally, more cost effective construction. Hybrid concrete construction, today, is a well-known term in the construction industry and is widely used in the UK and other developed countries. However, the use thereof is limited in South Africa, and in-situ concrete construction remains the conventional method of construction. Possible reasons for the limited use of hybrid concrete construction are investigated in this study. With the intent of improving the construction industry of South Africa, guidelines are provided to assist project teams in a decision between in-situ concrete construction and hybrid concrete construction. The decision between construction methods is based on many factors, such as project time, cost, quality, safety, environmental performance, socio-economic aspects (labour) and client satisfaction. Project time and cost are, however, the most important of these factors. It is stated that the structure of a building represents typically only 10 % of the construction cost, however, the choice of construction method and material can have significant effects on the cost of other elements throughout the life cycle of construction projects. It is therefore important to measure the whole life cycle cost when deciding between construction methods, such as in-situ concrete construction and hybrid concrete construction. The aim of this study is to identify and investigate the factors that influence project time and cost, throughout the life cycle of construction projects, and to provide a framework that can assist project teams in their decision between in-situ concrete construction and hybrid concrete construction in South Africa. The decision between these two construction methods is influenced by a vast number of variables that may be difficult to quantify. The framework therefore consists of qualitative information that can assist project teams in their decision. The framework provided in this study includes the factors that have an influence on the time and cost for a decision between in-situ concrete construction and hybrid concrete construction. These factors are identified for the three primary phases in the life cycle of construction projects. These phases are the design phase, the construction phase and the maintenance phase. / AFRIKAANSE OPSOMMING: Die konstruksiebedryf is 'n kompiterende mark en kontrakteurs moet op datum bly met nuwe konstruksie metodes en tegnologieë. In Suid-Afrika word daar van projek spanne vereis om vinnige besluite gedurende vroeë stadiums van 'n projek te neem. Hierdie besluite moet dikwels in 'n kort tydperk geneem word, en sluit die besluit tussen verskillende konstruksie metodes in, byvoorbeeld die besluit tussen in-situ en hibriede beton konstruksie. Hibriede beton konstruksie (HBK) is 'n kombinasie van in-situ en voorafvervaardigde beton elemente. HBK word in die algemeen gebruik om te baat uit 'n vinniger konstruksie tydperk, en kan soms ook ‘n meer koste-effektiewe metode van konstruksie wees. HBK word gesien as 'n bekende term in die konstruksiebedryf en word veral toegepas in ontwikkelde lande soos die VSA, Japan en Engeland. Die toepassing daarvan in Suid-Afrika is egter beperk. In Suid-Afrika word in-situ beton konstruksie nog steeds die meeste gebruik en staan dus bekend as die mees algemene metode van konstruksie. Hierdie studie ondersoek moontlike redes vir die beperkte gebruik van HBK in Suid-Afrika. Met die oog op 'n verbeterde konstruksiebedryf in Suid-Afrika, word rigylyne voorsien, wat projek spanne kan gebruik vir 'n besluit tussen in-situ en hibriede beton konstruksie. Daar is verskeie faktore wat 'n rol speel in die besluit tussen twee konstruksie metodes. Hierdie faktore sluit in, die tyd, koste, kwaliteit, veilighed, omgewings impak, sosio-ekonomiese aspekte (soos arbeid) en kliënt tevredenheid, van 'n projek. Tyd en koste is egter die belangrikste van hierdie faktore. Die metode waarvolgens 'n struktuur gebou word kan 'n beduidende uitwerking op die koste van ander elemente in die lewensiklus van 'n konstruksie projek hê. Dit is gevolglik belangrik om die hele lewensiklus koste in ag te neem wanneer daar besluit moet word tussen verskeie konstruksie metodes, soos in-situ en hibriede beton konstruksie. Die doel van hierdie studie is gevolglik om die faktore wat 'n invloed het op die tyd en lewensiklus koste van konstruksie projekte te identifiesieer. Hierdie faktore word dan gebruik om 'n raamwerk voor te stel. Projek spanne kan hierdie raamwerk gebruik as 'n riglyn om te besluit tussen in-situ en hibriede beton konstruksie. Die besluit tussen hierdie twee konstruksie metodes is afhanklik van 'n groot aantal veranderlikes, wat moeilik is om te kwantifiseer. Die raamwerk bestaan dus uit kwalitatiewe inligting wat projek spanne kan gebruik om 'n ingeligte besluit te neem oor in-situ en hibriede beton konstruksie. Die raamwerk wat in hierdie studie voorgestel word sluit dus die faktore in wat 'n invloed het op die tyd en koste vir 'n besluit tussen in-situ en hibriede beton konstruksie. Hierdie faktore is geïdentifiseer vir die drie primêre fases in die lewensiklus van 'n konstruksie projek. Hierdie fases is die ontwerp fase, die konstruksie fase en die onderhoud fase.

Western Palm Beach County, FL is characterized by thick deposits organic soils at shallow depths. Because of their high void ratio and compressibility, these soils undergo large primary consolidation followed by extended periods of secondary compression causing excessive premature structural distress. Although soil stabilization has been largely used with remarkable results in soft, expansive and non-organic soils, limited research and practice exist in the implementation with highly organic soils. The main motivation of this research was to investigate the effects of cement stabilization on the compressibility behavior of organic rich soils, and develop mix design criteria for optimum cement contents necessary to induce the desired engineering behavior. This optimized mix design may provide guidelines for Deep Mixing Methods in organic soils. / by Juan Ramirez. / Thesis (M.S.C.S.)--Florida Atlantic University, 2009. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2009. Mode of access: World Wide Web.

The diploma thesis deals with construction technological project of shopping centre Breda & Weinstein in Opava. The thesis handles technological prescriptions of cast-in-place reinforced concrete constructions and ventilated facade made of large format precast elements with graphical surface. There is machine assembly, design of site equipment, control and test plan and computation of time of formwork dismantle for the realization of reinforced concrete constructions. There is also time and financial plan, itemized budget with bill of quantities and construction schedule for earthwork, building foundations and cast-in-place constructions.