Master of Science / Department of Architectural Engineering / Bill Zhang / In structural engineering, it can be challenging to incorporate a sustainable design without sacrificing structural integrity. However, flat plate voided slabs are an interesting alternative to standard flat plate concrete slab systems due to the reduction in concrete and the recycled plastic void formers that are located inside the slab. This research is necessary because an increased use of voided slabs in concrete structures would help fight climate change by reducing the CO₂ emissions caused from cement production. This report will discuss the advantages and disadvantages of implementing plastic void formers into solid flat plate slabs and examine a parametric study comparing voided flat plate slabs to solid flat plate slabs. The design of the voided slabs follows the CRSI Design Guide for Voided Concrete Slabs while also referencing the ACI 318-14 Building Code Requirements for Structural Concrete. Three different slabs for typical square bay sizes of 25 feet, 30 feet, and 35 feet are designed to compare the effectiveness of voided slabs to traditional solid slabs.

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This diploma thesis deals with the static assessment of selected parts of the panel building of the former boarding school, for which adaptation to separate housing units and extension of one floor is planned. Upon the planned change of layout, extensions of the original door openings and new openings are proposed. The work assesses the object in its original state with the included unprofessional interference in statics during its use, and the object in the final state with planned modifications of the openings and proposes solutions to secure unsatisfactory areas to suit the new state loads

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The use of lipped channel members as the reinforcing for composite beams in rib and block type slab systems is advantageous due to its lightweight nature which facilitates efficiently in construction. The main consideration in the design if such composite members is the integrity of the shear bond at the concrete/ steel interface. Premature de-bonding of the concrete from the steel results in an overall loss of structural strength of the composite member. Certain guidelines are to be established to facilitate in the design of such systems. In this research project the shear bond strength of composite members using lipped channel members is investigated by interrogating the results from three independent research experiments. Design formulas from first principles are developed to more easily benchmark the behaviour of such members. Complex and simple equations are developed and the results obtained are compared to similar shear bond stresses obtained from literature. A reasonably acceptable correlation is achieved. A comparative study was also carried out between the various experimental beams regarding vertical shear, flexural strength and short-term deflections. The purpose was to ascertain what effect early shear bond failure has on these structural properties. The formulas used to benchmark the results were the well known formulas used for the design and evaluation of reinforced concrete members. The results were tabulated showing the difference between the calculated and experimental results. As a result of the investigation the following conclusions seem justified :  The simple equations as developed for horizontal shear failure give acceptable results which are within the range as given by more complex equations.  The composite beam has a certain amount of reserve shear strength even after the initial onset of horizontal shear failure. iv  The reinforcing ratio, the concrete strength and the slenderness ratio of the composite beam all have an influence on the level of horizontal stress failure.  The composite beams tend to fail at levels higher than that predicted by the homogeneous shear equations but lower than the predicted flexural equations. The parameters which influence this are again the reinforcing ratio, the concrete strength and the slenderness ratio.  Once a composite beam has experienced shear bond failure the deflection integrity of the beam is completely compromised. The above conclusions show the designer that caution must be exercised when using lipped channel members in rib and block slab systems.

A number of recently constructed bridge approach slabs using an articulation at mid span and the wide flange terminal anchorage system have experienced settlement at their expansion joints. This problem is more commonly referred to as the bump at the end of the bridge. This study investigated reasons for the bumps and recommended ways to improve the current situation. To find out possible causes of the bridge approach slab problem, literature review, questionnaire survey, and a visual inspection for 18 Houston sites were conducted. Based on the results, two bridge sites in Houston, Texas, were selected for detailed investigation. An extensive series of laboratory and field tests were performed at each site. The main causes of bump at two study sites were compression of embankment soil and natural soil, and poor compaction of embankment soil. The finite-element computer program ABAQUS was used to evaluate behavior of the current approach slab design and of a possibly more effective design. The results show that the transition zone is about 12 m with 80 percent of the maximum settlement

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A number of recently constructed bridge approach slabs using an articulation at mid span and the wide flange terminal anchorage system have experienced settlement at their expansion joints. This problem is more commonly referred to as the bump at the end of the bridge. This study investigated reasons for the bumps and recommended ways to improve the current situation. To find out possible causes of the bridge approach slab problem, literature review, questionnaire survey, and a visual inspection for 18 Houston sites were conducted. Based on the results, two bridge sites in Houston, Texas, were selected for detailed investigation. An extensive series of laboratory and field tests were performed at each site. The main causes of bump at two study sites were compression of embankment soil and natural soil, and poor compaction of embankment soil. The finite-element computer program ABAQUS was used to evaluate behavior of the current approach slab design and of a possibly more effective design. The results show that the transition zone is about 12 m with 80 percent of the maximum settlement

Natural language pipelines consist of various natural language algorithms that use the annotations of a previous algorithm to compute more annotations. These algorithms tend to be expensive in terms of computational power. Therefore it is advantageous to parallelize them in order to reduce the time necessary to analyze a large document collection. The goal of this project was to develop a new framework to encapsulate algorithms such that they may be used as part of a pipeline without any additional work. The framework consists of a custom-built data structure called Slab which implements type safety and functional transparency to integrate itself into the Scala programming language. Because of this integration, it is possible to use Spark, a MapReduce framework, to parallelize the pipeline on a cluster. To assess the performance of the new framework, a pipeline based on the OpenNLP library was created. An existing pipeline implemented in UIMA, an industry standard for natural language pipeline frameworks, served as a baseline in terms of performance. The pipeline created from the new framework processed the corpus in about half the time. / text

Since concrete bridge deck slabs are much longer in the traffic direction, they experience transverse early-age cracks due to volumetric instability and restraint. In the last decade, the lower cost of the non-corrodible Glass Fiber Reinforced Polymer (GFRP) bars, as alternative to steel reinforcement, has made them attractive to the bridge construction industry. However, low modulus of GFRP bars may lead to wider cracks in GFRP-RC structures. This serviceability issue can be aggravated by harsh environmental conditions. Hence, the main objective of this thesis is to investigate the effect of early-age cracking in restraint bridge deck slabs reinforced with GFRP bars subjected to different environments. This research consists of two phases: an experimental investigation and a numerical study. In the experimental phase, four full-scale cast-in-place slabs reinforced with different longitudinal GFRP reinforcement ratios (0.30, 0.50, 0.70 and 1.1%) and one with steel reinforcement ratio of 0.7% measuring 2500 mm long × 765 mm wide × 180 mm thick were constructed and tested in the laboratory. Three environmental conditions were implemented; normal (laboratory) adiabatic conditions as well as freezing-thawing and wetting-drying cycles. The main test results are presented in terms of cracking pattern, width and spacing, and strains in the reinforcement and concrete. Test results indicated that the minimum reinforcement ratio (0.7%) recommended by CHBDC for bridge deck slabs reinforced with GFRP bars satisfied the serviceability requirements after being subjected to the simulated exposures of normal laboratory conditions, freezing-thawing, and wetting-drying cycles. In the numerical phase of this research, a finite element model (FEM) was constructed using ATENA software package (ver. 5) to simulate the behaviour of the test specimens. According to the FEM results, a reinforcement ratio of 0.45% Carbon FRP (CFRP) can control the early-age crack width and reinforcement strain in CFRP-RC members subjected to restrained shrinkage. Also, the results indicated that changing the bar surface texture (sand-coated and ribbed bars) or concrete cover had an insignificant effect on the early-age crack behavior of FRP-RC bridge deck slabs subjected to shrinkage. However, reducing bar spacing and concrete strength resulted in a decrease in crack width and reinforcement strain. / October 2015