Browsing by Subject "Buildings"
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Item A model for probable maximum loss in hurricanes(Texas Tech University, 1997-05) Unanwa, Christian OnyeanwunaThe quantitative prediction of wind damage to structures has emerged in recent times as a major issue confronting construction and insurance industry personnel as well as emergency management planners. While a majority ofthe structures in the coastal areas exposed to hurricanes are non-engineered damage-prone buildings, these same buildings are insured against wind damage. Reliable insurance underwriting for structures, efficient wind damage mitigation programs, and post-storm recovery strategies are all dependent upon good quantitative damage prediction. A new approach using the concept of building damage bands is proposed for predicting the probable maximum damage degree to individual buildings or groups of buildings for any given hurricane scenario. The damage prediction model employs an objective weighting technique driven by component cost factors, conditional failure probabilities, and location parameters to obtain upper and lower hurricane damage thresholds. Component failure probabilities were obtained via a quasi fault tree analysis of a multiple fault tree scheme in which the damage of individual building envelope components, including the building interior, serve as the Top events. Important phenomena such as damage propagation and common cause failures which complicate the wind damage process were considered in the present model.Item A Quasi-Dynamic HVAC and Building Simulation Methodology(2012-07-16) Davis, Clinton PaulThis thesis introduces a quasi-dynamic building simulation methodology which complements existing building simulators by allowing transient models of HVAC (heating, ventilating and air-conditioning) systems to be created in an analogous way to their design and simulated in a computationally efficient manner. The methodology represents a system as interconnected, object-oriented sub-models known as components. Fluids and their local properties are modeled using discrete, incompressible objects known as packets. System wide pressure and flow rates are modeled similar to electrical circuit models. Transferring packets between components emulates fluid flow, while the system wide fluid circuit formed by the components' interconnections determines system wide pressures and flow rates. A tool named PAQS, after the PAacketized Quasi-dynamic Simulation methodology, was built to demonstrate the described methodology. Validation tests of PAQS found that its steady state energy use predictions differed less than 3% from a comparable steady state model. PAQS was also able to correctly model the transient behavior of a dynamic linear analytical system.Item A synergistic approach to the design of energy responsive office buildings(Texas Tech University, 1992-12) Ngo, Huy SinhBuildings consume energy principally in the process of environmental control. During the nineteenth century, building services were simple, and they interacted with the exterior climate. Buildings were daylit; artificial lighting was provided by gas or oil lamps; cooling was by ventilation; and heating was by gas or steam or by open fires. However, during the early part of the twentieth century when fuel prices were low, new methods and new equipment for heating, cooling and lighting were developed. It seemed possible that a perfect, controllable interior environment could be provided at any time and place because buildings no longer needed to interact with the outdoor environment. This building design approach was readily accepted and became the standard environmental solution for buildings. The modern multi-story office building is the best example of a highly controlled and comfortable living and working environment. "Technological innovations such as mechanical air-conditioning, fluorescent lighting, and temperature and humidity control devices allowed for a climate-rejecting control approach to office buildings to become the standard design solution during the past few decades" (Ruck,1989,p.4). The climate-rejecting environmental-control approach excludes the direct influence of exterior climate on the interior environment and provides all services internally from controlled sources. Office buildings designed in this way no longer have to make any connection between their occupied space and the external environment. Many of them rely on sophisticated mechanical devices to maintain internal environmental comfort.Item A uniform approach to design of windloads on structures(Texas Tech University, 1987-12) Chen, Yuan-Bin"Uniform" is defined as having the same manner, and "approach" is defined as a path road or other means of reaching a certain thing. Therefore, combining these two words, "uniform approach," means having the same manner of reaching a certain thing in general. A uniform approach to design for wind ioads implies using the same methodology when treating straight winds, hurricane winds and tornado winds.Item An artificial neural network for wind-induced damage potential to nonengineered buildings(Texas Tech University, 1996-12) Sandri, PraveenExtreme winds such as hurricanes and tomadoes can be extremely destmctive and result in catastrophic property losses and loss of human lives. The need to predict damage and reduce loss of life and property is becoming more important with increasing urban sprawl. Artificial Neural Networks (ANNs) provide a novel approach for representing the wind-induced damage potential prediction model. Modeled loosely after the biological neural networks of the human brain, ANNs are generally used in situations where the interactions between the input and the output variable are too complicated for an analytical solution or where there is not suflficient understanding of the problem domain. Predicting wind-induced damage potential to nonengineered buildings is not a simple task because of the complexity of constmction and limited understanding of the wind efifects on buildings. This research concentrates on the investigation of the applicability of ANNs to wind-induced damage potential prediction and the corresponding implementation issues. Even after years of post disaster windstorm damage investigations consistent, complete and robust damage information is not available to train the ANN. Thus, synthetic data instead of observed building damage information is used. WIND-RITE*, a knowledge based expert system for grading individual buildings in windstorms is used to provide the necessary damage information for the synthetic data. This research shows that a feedforward multi-layer neural network with a modified backpropagation learning algorithm can be used effectively to model wind-induced damage potential predictions for nonengineered buildings. As few as four hundred building samples are suflficient to train the network to leam the underlying relationships between the features of the building and its corresponding building damage potential. During training the ANN model is able to leam the relationships between the input features and the resulting building damage grade eflfectively. It was also found that the ANN is able to predict reasonably for samples it has not seen before.Item Analysis of blockage effects on urban cellular networks(2013-05) Bai, Tianyang; Heath, Robert W., Ph. D.Large-scale blockages like buildings affect the performance of urban cellular networks, especially in the millimeter-wave frequency band. Unfortunately, such blockage effects are either neglected or characterized by oversimplified models in the analysis of cellular networks. Leveraging concepts from random shape theory, this paper proposes a mathematical framework to model random blockages, and quantifies their effects on the performance of cellular networks. Specifically, random buildings are modeled as a process of rectangles with random sizes and orientations whose centers form a Poisson point process on the plane, which is called a Boolean scheme. The distribution of the number of blockages in a link is proven to be Poisson with parameter dependent on the length of the link, which leads to the distribution of penetration losses of a single link. A path loss model that incorporates the blockage effects is proposed, which matches experimental trends observed in prior work. The blockage model is applied to analyze blockage effects on cellular networks assuming blockages are impenetrable, in terms of connectivity, coverage probability, and average rate. Analytic results show while buildings may block the desired signal, they may still have a positive impact on network performance since they also block more interference.Item Analysis of reference pressure systems used in field measurements of wind loads(Texas Tech University, 1993-05) Levitan, Marc LloydThe main problem then left to be solved for making accurate measurements of wind-induced pressures on full-scale structures lies in reaching a greater understanding of the effects of reference pressure systems on these measurements. At present, it is difficult to even quantify the measurement error associated with the reference pressure system, and little information is available to help improve reference pressure system design.Item Application and analysis of RANS based turbulence models for bluff body aerodynamics(Texas Tech University, 2004-12) Unhale, Sanket A.Computational Wind Engineering (CWE) is becoming more popular in the wind engineering community, for prediction of the wind loads on buildings and structures. The most important and basic requirement of CWE is successful modeling of turbulent flow in the simulated atmospheric boundary layer. Many turbulence models have been proposed and tested for a variety of flows, but they are not accurate enough to simulate the bluff body aerodynamics accurately. In the similar context, five two-equation turbulence models based on the isotropic eddy viscosity concept and Reynolds Averaged Navier Stokes (RANS) modeling approach were tested for the flow around sharp edged building models using Fluent as the solver. The numerical results were compared with the experimental findings in wind tunnel simulations and full scale measurements available in the literature. The results illustrate inaccuracy of the turbulence models to predict the pressure distribution along the building surfaces. The results were analyzed and the effects of different turbulence parameters used in the modeling and analysis were discussed. Each turbulence model was individually reviewed for the correctness of its predictions and the best model in this set was chosen. This model was further applied to different obstacle geometry in different experimental conditions to minimize the effects of unique experimental condition on analysis. One of the major problems encountered in the modeling was the type of near wall treatment used for simulation. Development of equilibrium boundary layer in the wind tunnel was used as a test condition for studying the deficiencies in different types of near wall modeling approaches. It was concluded that the standard approach of wall functions was insufficient to estimating the effects of roughness on the wall boundary on the mean flow. A new rough wall model proposed by Durbin et al [58] was implemented using the user defined functions capability of Fluent. This model was tested on a variety of flows; like flow through pipe, flow over a backward facing step, etc. This flow was then applied to the models tested in this project to analyze the effects on the rough wall model used for modeling near wall effects. Overall agreement between the computational predictions and experimental findings was acceptable.Item Bridging: An alternative project delivery method(1998-08) McNall, Todd W.Item Bridging: an alternative project delivery method(Texas Tech University, 1998-08) McNall, Todd W.The most common project delivery methods, design/bid/bulld and design/build, have flaws in them that raise issues with each of the methods. These project delivery methods have, "Systematic contradictions ... [that] have taken a toll on clients who must ultimately be satisfied if the architectural profession is to continue to flourish." Some of the issues also stem from the way most architectural firms practice architecture using these project delivery methods. The first issue concerns the extended length of time and the extensive cost required to get a fixed construction cost for a project. The next concern affecting project delivery is that architects are not at the forefront of understanding the most current building technology and often do not consider construction technology during the design process resulting In higher construction costs for a given quality level. These extensively used project delivery methods also open the possibility for change orders and litigation throughout the process which can result in a project costing much more than it should cost. Bridging addresses these issues and others because it Is a hybrid of the better parts of design/build and the traditional design/bid/bulld approach. Bridging consists of an owner's architect defining requirements and developing schematic design, and performance requirements. A contractor is then brought in through a bidding process or other arrangements, and the contractor's architects and engineers work with the contractor and the owner's architect to produce final construction documents and specifications. The owner's architect monitors and oversees this work and approves payments for the work. The contractor then builds the owner-approved plans while the owner's architect administers the contract and approves payment.Item Buddy Holly Museum, an adaptive re-use approach(Texas Tech University, 1997-12) Robertson, Stanley AndrewIn an ever-increasing need for the practice of adaptive re-use, there remains the growing problem of the contrasting ideas of re-use. The National Trust's Courthouse Conservation Handbook defines restoration as the "scholarly research" and act of the retaining the existing structure. It goes on to define rehabilitation as "little effect on the original fabric" and defines conservation as the "sensitive attempt to integrate...modern additions." The issue of adaptive re-use in architecture is changing much like the culture and history of the particular pieces of architecture that fall into that category. Although there are the evident contrasting ideas of how far one can add, alter, and enhance existing architecture to bring it back from dead space, there is a sense of understanding beginning to surface. Adaptive re-use is at odds with the traditional goals of preservationists. A prominent preservation expert Swanke Hayden Connell Architects' Theodore Prudon reasons that "traditional rules won't apply to recent buildings" and is ready to argue for some flexibility in some categories.Item Building oriented documentation systems(Texas Tech University, 1995-05) Rector, Scott WillisThis thesis uses the concept of a building team approach; that is to say all members of the building team collaborate throughout the entire building process. In this thesis the term "building process" denotes the decision, design, construction, and facilities' management phases a building goes through during its life cycle. Likewise, the "building team" refers to all specialties that are involved in the building process [Grant, 1986; Griffen, 1972; Rush, 1986; Ehrenkrantz, 1989]. The building team increases in size and complexity in direct proportion to the size and complexity of both the client organization and the proposed project [Gutman, 1988; Staslowaski, 1993; Coxe, 1980; Rose, 1987], and may comprise several firms of the same discipline, each with a particular specialty. For example, a project may have architectural firms acting as designers, project coordinators and client representatives, as well as performing construction documentation and construction administrative services. Architects may specialize in a building type or in a particular service that meets client demands for expertise in management of building complexity [Gutman, 1988; Rose, 1987; Stasiowaski, 1990].Item Climate action strategies for the University of Texas at Austin(2010-05) Hernandez, Marinoelle; Eaton, David J.; Walker, Jim H.This report analyzes the current greenhouse gas emissions inventory for The University of Texas at Austin (UT-Austin), reviews the carbon reduction strategies being implemented at UT-Austin and other peer institutions, and offers recommendations for strategies that could reduce greenhouse gas emissions at UT-Austin in the future.Item Computer classroom wall color preference and personality type of college students(Texas Tech University, 2003-08) Wang, HongWith the advent of the digita! era, computers are commonly used in teaching and leaming systems. The computer classroom is widely used in colleges and high schools in the United States. In order to create a more comfortable and effective teaching and studying environment, the most desirable wall colors for a computer classroom were identified in this study. Also, interior design students' classifications, and personality types were tested to determine if these factors have impact on their wall color preference. Two instmments were used: the Wall Color Preference Test, and the Myers-Briggs Type Indicator. The population for this study were 145 undergraduate students majoring in interior design at a university located in the southwestem United States. Students were asked to voluntarily participate in the Wall Color Preference Test. For this test, students ranked 15 slides displayed on a screen that depicted the same computer classroom and under the same lighting condition (8 parabolic fluorescent lighting fixtures) but with 15 different wall colors. The students also completed the Myers-Briggs Type Indicator. Personality type was examined in regards to its influence on preference for interior color applications. A pilot study using the same methodology was conducted prior to the population test in order to identify any problem with the questionnaire and with the procedure selected to coUect data. Data from the study were analyzed by using one-way repeated measure analysis of variance (ANOVA), Boferroni HSD post hoc test, and bivariate correlation analysis to detemiine overall preference and to reveal relationships between students' personality types, classifications and knowledge background have on their preference for wall colors of computer classrooms. The results determined that the interior design students do have color preference for the 15 images. The results also revealed that students' classifications, knowledge background had impact on colors used in image2, 6, and 12, but not on others. Results also found that students' personality types had no impact on their wall color preference for a computer classroom. This study suggested cool colors in the Master Palette Color System are more desirable colors for walls of a computer classroom.Item Direct measurement of wind loads on a low-rise test building(Texas Tech University, 1998-05) Bird, Mark WesleyWind loads on low-rise structures are studied in the field primarily so that the results obtained can be used to provide a base-line data set and to assist in wind tunnel studies. The objective of this work is to develop a means of directly measuring total wind loads in the field on a low-rise test building. This project is part of the Texas Tech University / Colorado State University Cooperative Program In Wind Engineering to study wind effects on low-rise buildings. The experimental facility utilized is the Wind Engineering Research Field Laboratory (WERFL) on the campus of Texas Tech University. This thesis contains development of an experimental procedure for directly measuring total wind-induced loads (total horizontal shear and uplift) on the 30 ft x 45 ft x 13 ft test building along with some preliminary results. These loads are measured by supporting the entire building on four load cells(one at each corner). The load cells were constructed in the laboratory to register force in the three orthogonal directions. Forces recorded by the load cells and pressures recorded at the 12 pressure taps (windward wall, roof and leeward wall) are used to measure wind-induced loads. Data utilized In this project is limited to records with winds normal to long axis of the building collected in February and March of 1995. A total of twelve 15-minute records are used in the analysis. Analysis of data indicates difficulty in obtaining a reference load (when wind Is zero). A procedure to overcome this difficulty is suggested. Preliminary results show that overall loads measured using the load cells are smaller than the ones obtained from the integration of pressure tap values. However, there is significant uncertainty and scatter in the results obtained from the load cells.Item Economic investigation of masonry construction for wind resistant design(Texas Tech University, 1996-12) Luo, SiweiNot availableItem Energy and environmental contexts of cities, transportation systems, and emerging vehicle technologies : how plug-in electric vehicles and urban design influence energy consumption and emissions(2013-12) Nichols, Brice G.; Kockelman, KaraThis thesis is divided into two parts. The first evaluates the role of the built environment in life-cycle energy consumption, by comparing different neighborhood and city styles. Through a holistic modeling and accounting framework, this work identifies the largest energy-consuming sectors, among residential and commercial buildings, personal vehicles and transit trips, and supporting infrastructure (roads, sidewalks, parking lots, water pipes, street lighting). Life-cycle energy calculations include operational energy use (e.g., gasoline for vehicles, electricity and natural gas for buildings) and embodied energy used to produce materials and construct buildings and infrastructure. Case study neighborhoods in Austin, Texas, and larger-scale regional models suggest that building energy demands comprise around 50% of life-cycle energy demands, while transportation demands (from driving and infrastructure alike) contribute around 40%, across all cases. However, results also suggest that population density and average residential unit size play a major role in defining per-capita energy consumption. Operational demands made up about 90% of life-cycle energy demands, suggesting that v most urban energy savings can be obtained from reduced personal vehicle trips and more efficient vehicles and buildings. Case study comparisons suggest that neighborhoods and regions with greater density and higher share of multi-family housing units tend to reduce operational (and thus life-cycle) energy demands with less travel demand and decreased home and work energy use, per capita. The second part of this modeled plug-in electric vehicle (PEV) emissions impacts in Texas, by considering four possible vehicle adoption scenarios (where PEVs make up 1, 5, 10, and 25% of total passenger vehicles). The analysis anticipates PEV electricity demand and emissions rates, based on current Texas power grid data. Results indicate that PEV emissions depend significantly on which specific power plants are used to power the vehicles, but that PEVs' average per-mile emissions rates for NO[subscript x], PM, and CO₂ are all likely to be lower than today's average passenger car, when today's average mix is used. Power produced from 100% coal plants could produce 14 times as much NO[subscript x], 3,200 times as much SO₂, nearly 10 times as much CO₂ and CO₂eq, 2.5 times as much PM₁₀, and VOCs, and nearly 80 times the NO₂ compared to a grid with 100% natural gas plants.Item Environmental design directed at decreasing the wind damage experienced from hurricanes in single-family residential communities(Texas Tech University, 1997-12) Gardner, Anna G.In 1992 hurricane Andrew inflicted approximately $25 billion in damage in Dade county, FL, resulting in the costliest hurricane in U.S. history (Landsea 1997 Internet). Documentation and analysis of hurricane Andrew's wind damage substantiates Minor and Mehta's (1979) identification of initiation points of failure in low-rise structures experienced during tomadic winds. These initiation points of failure occur at points experiencing high wind pressures which a direct resuh of poor aerodynamic configurations found in most conventional buildings (Minor and Mehta 1979 pg. 2285). If the aerodynamics of a structure influence which components of a building frequently fail, then one could reason that the aerodynamics of a community would influence which structures will frequently fail. This study identifies five street/road patterns or typologies commonly found within a residential community. The aerodjmamic qualities of each typology are predicted and each structure in the pattern is rated according to the expectation of damage relative to the structure's location. Once these damage herarchy predictions are made a case study community is coded according to the degree of roof damage each structure experiences in order to prove or disprove the initial hypothesis. The case study is a community damaged by hurricane Andrew on 24 August 1992, located in east Culter Ridge, Florida and has an approximate area of 2.15 km^ (0.83 mi^). Windbreak placements are suggested for improving the aerodynamics for each intersection typology along with suggestions for improving the wind flow around individual structures and their use in combating windbome debris. The objective of this thesis is to create design recommendations to aid community designers, developers, architects, and engineers in analyzing and improving new and existing communities for extreme winds.Item Evaluation of a building with respect to wind in an integrated windows environment(Texas Tech University, 1995-12) Teal, Mark H.Evaluating a building's performance in a windstorm has previously been a long, coitputationally intensive, manual process. It has also required the time of an expert to perform all of the calculations to insure the latest knowledge of wind/building interaction is properly used to guide the process and interpret the results. This paper presents the integration of a knowledge based expert system with more traditional algorithmic programs in an effort to automate the evaluation. The expert system uses knowledge gleaned from actual experts in wind engineering to guide the repetitive calculations and comparisons, which the algorithmic programs can accorrplish many times faster than a human. The Microsoft Windows operating system offers a number of different methods of intertask communication, user interaction, and data management. Ultimately, the user must have convenient access to the database auid knowledge base, as well as an accurate analysis of the building. Different combinations of intertask communication have been explored, noting their appropriateness in terms of memory limitations and time consumption.Item Full-scale study of conical vortices and their effects near roof corners(Texas Tech University, 2000-05) Wu, FuqiangInvestigations of wind-induced building damage have shown that roof and roofing systems are the most vulnerable parts of the whole building envelope to fail, and damages to the roof typically initiate around the roof comers and edges where extremely high suctions occur because of the flow separation. It is known that the high suctions near the roof comers and edges are mainly induced by a separated flow phenomenon — conical vortices. Full-scale experiments were conducted at Wind Engineering Research Field Laboratory (WERFL) of Texas Tech University with the aim to understand the mechanism for generation of conical vortex flow and the associated high roof surface suctions. A synchronized data acquisition system was set up on the roof of the experimental building at WERFL to simultaneously collect conical vortex images and the data of approaching wind and roof comer suction pressures. Extensive flow visualization and pressure measurement experiments were carried out, and over 100 reliable 15-minute data runs were collected. These vortex-image-synchronized data were subjected to systematic analyses to improve our understanding of this conical vortex flow phenomenon.