Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2007. / Includes bibliographical references (leaf 48). / A support tower is the main structure which would support rotor, power transmission and control systems, and elevates the rotating blades above the earth boundary layer. A successful design should ensure safe, efficient and economic design for the whole wind turbine system. It should provide easy construction and easy access for maintenance of the rotor components and sub-components. UHPC materials have been used in various structural applications, such as highway bridge girders. There is no much research about its application in support structures of wind turbines. After meeting the requirements for loads, minimizing cost is the next most important design driver. Here at MIT, Chuang and Professor Ulm developed a new constitutive model for fiber reinforced cementitious composite materials, which is particularly suitable for high performance cementitious composites including UHPC. On the basis of UHPC material model and the load requirements for wind turbines, the objective of this work is to carry out a tentative design of the UHPC support tower for a prototype wind turbine. / (cont.) Two tube-type cross sections are examined. The 3-d analysis reveals a sufficient flexural performance of the UHPC support tower when subjected to the extreme wind loads. Since this work only focuses on the extreme wind load case, other load cases, such as aerodynamic and operational cases, should be considered before it can be safely employed. / by Zheng Wang. / M.Eng.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2001. / Includes bibliographical references (leaves 83-84). / by Mark E. Orwat. / S.M.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2011. / Cataloged from PDF version of thesis. / Includes bibliographical references (p. 136-138). / This research develops a Landslide Hazard Rating System for the rainfall-induced landslides in the Chenyulan River basin area in central Taiwan. This system is designed to provide a simplified and quick evaluation of the possibility of landslide occurrence, which can be used for planning and risk management. A systematic procedure to investigate the characterization of rainfall distribution in a regional area is developed in the first part of the thesis. Rainfall data for approximately one decade, 2002 to 2008, from 9 rainfall stations in the study area are included, in which a total of 46 typhoons are selected and categorized into 3 typhoon paths: the Northeastern, Northwestern, and Western. The rainfall distribution affected by typhoon paths in a region is thereby determined. The second part of the thesis is the Landslide Hazard Rating System, which integrates different hazard factors: bedrock geology, aspect, and slope gradients. This analysis is based on the specific characterization of the study area, which consists of the relative topographic relief (aspect and slope gradients) and variable bedrock geology. The method of normalized difference is used for examining the relationship of the topographic features to landslide occurrence. Although this study is conducted in a specific area, this landslide hazard rating system can be applied to other locations. Finally, a concept of a rainfall-induced landslide analytical system is proposed to combine the rainfall distribution analysis and the landslide hazard rating system. This analytical system is intended to include and address the relationship of rainfall and landslide occurrence by combining characterizations of rainfall, topography, and landslide potential. Additionally, this study recommends that, in future work, theoretical models of rainfall distribution and laboratory tests of soil and rock samples be included. Together, these will constitute a basis for the prediction of landslide occurrence. The ultimate goal of future work should be the development of a system for assessing and forecasting rainfall-induced landslide risks, which can become the foundation for a comprehensive risk management system for use in planning. / by Yi-Ting Chen. / S.M.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2000. / Includes bibliographical references (p. 115-119). / by Karen Paula L. Veroy. / S.M.

Thesis: M. Eng., Massachusetts Institute of Technology, Department of Civil and Environmental Engineering, 2014. / Cataloged from PDF version of thesis. / Includes bibliographical references (pages 71-73). / Engineers are well-placed when calculating the required resistance for natural and non-natural hazards. However, there are two main problems with the current approach. First, while hazards are one of the primary causes of catastrophic damage and the design against risk contributes vastly to the cost in design and construction, it is only considered late in the development process. Second, current design approaches tend to provide guidelines that do not explain the rationale behind the presented values, leaving the engineer without any true understanding of the actual risk of a hazard occurring. Data is a key aspect in accurate prediction, though its sources are often sparsely distributed and engineers rarely have the background in statistics to process this into meaningful and useful results. This thesis explores the existing approaches to designing against hazards, focussing on natural hazards such as earthquakes, and the type of existing geographic information systems (GIS) that exist to assist in this process. A conceptual design for a hazard-related GIS is then proposed, looking at the key requirements for a system that could communicate key hazard-related data and how it could be designed and implemented. Sources for hazard-related data are then discussed. Finally, models and methodologies for interpreting hazard-related data are examined, with a schematic for how a hazard focussed system could be structured. These look at how risk can be predicted in a transparent way which ensures that the user of such a system is able to understand the hazard-related risks for a given location. / by Oliver Edward Newth. / M. Eng.

Thesis: M. Eng., Massachusetts Institute of Technology, Department of Civil and Environmental Engineering, 2017. / Cataloged from PDF version of thesis. / Includes bibliographical references (pages 59-61). / In strong wind events like tornado and hurricane, significant destruction is caused to buildings due to wind-borne debris, which are usually damaged structural members and components with insufficient attachment. This debris, also referred to as missiles, can penetrate building walls and roofs and jeopardize human life. Because of this, there are standard impact criteria provided by Federal Emergency Management Agency (FEMA-P-320, 2014; FEMA-P-361, 2015) and International Code Council (ICC-500, 2014) that need to be met when designing safe rooms or storm shelters. The national wind institute at Texas Tech University has done extensive impact testing on different types of structural and non-structural components, which are the basis for current design guidelines. This thesis focuses on investigating previously developed methods for evaluating the perforation of concrete and steel targets and selecting the most relevant formulas that can be applied for the design of tornado safe rooms. For cast-in-place(CIP) concrete, precast concrete and concrete masonry units (CMU), the best method to estimate perforation limit is the Central Research Institute of the Electric Power Industry (CRIEPI) Formula. For Steel target, both the Ballistic Research Laboratory (BRL) Formula and the Stanford Research Institute (SRI) give useful estimate for perforation limit. These selected concrete and steel target perforation limit formulas can be used for preliminary design of buildings, to withstand the required impact criteria, giving engineers the flexibility to design structures without depending only on using structural components that have been tested to meet the FEMA criteria. / by Selam Mulugeta Gebru. / M. Eng.

Thesis: Ph. D., Massachusetts Institute of Technology, Department of Civil and Environmental Engineering, 2015. / This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections. / Cataloged from student-submitted PDF version of thesis. / Includes bibliographical references (pages 141-156). / Satellite-derived retrievals of precipitation have increased in availability and improved in quality over the last decade. There are now several satellites in orbit with instruments capable of precipitation retrieval with various degrees of accuracy, spatial resolution and temporal sampling. These retrievals have the advantage of almost full global coverage when compared to surface gauges and ground-based radars. However, there are uncertainties associated with each of these retrievals. This thesis focuses on developing a new framework for characterizing uncertainties in remotely-sensed precipitation estimates. This characterization is a prerequisite if these estimates are to be used in hydrological models. Precipitation forcing is the primary source of uncertainty in surface hydrological models used for forecasting and data assimilation. In the first part of the thesis, a new metric of error is applied to evaluate precipitation products from Special Sensor Microwave/Imager (SSM/I) instrument. The SSM/I microwave measurements are used for quantitative precipitation rate retrievals and they are key to the development of precipitation data products with high temporal sampling. Results show marked seasonality and precipitation intensity dependence as well as a lower bias at higher intensities and in geographic locations where precipitation rates are generally higher. Next, a new stochastic method is developed to generate spatially intermittent precipitation replicates. These replicates constitute a prior population that can be updated in a Bayesian framework using observations. Bayesian approach allows us to both merge different measurements and investigate the associated uncertainties. Finally, a new ensemble-based approach to the characterization of uncertainties (in both magnitude (intensity) and phase (location)) associated with precipitation retrieval from space-born instruments is introduced. Unlike previous studies, this method derives the error likelihood using an archive of historical measurements and provides an ensemble characterization of measurement error. The ensemble replicates are generated using the proposed stochastic method, and they are intermittent in space and time. The replicates are first projected in a low-dimensional subspace using a problem-specific set of attributes. The attributes are derived using a dimensionality-reduction approach that takes advantage of singular value decomposition. A non-parametric importance sampling technique is formulated in terms of the attribute vectors to solve the Bayesian sampling problem. Results indicate that this ensemble estimation approach provides a useful description of precipitation uncertainties with posterior ensemble that is narrower in distribution than its prior. / by Seyed Hamed Alemohammad. / Ph. D.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 1996. / Vita. / Includes bibliographical references (leaves 225-231). / Caleb K. King. / Ph.D.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2004. / Includes bibliographical references (p. 133-138). / In this thesis we describe the development of a wireless sensor module for tunnel monitoring. The tunnel in question is a part of the London Underground system. Construction of a new tunnel beneath the existing tunnel is anticipated to cause quantifiable vertical displacement. To ensure safe operation of the tunnel during the construction activity, a real-time monitoring system has been created to measure vertical displacements along the critical zone near Highbury & Islington station. A geomechanical analysis, provided by a third party, is used to establish the allowable maximum displacement. A custom wireless sensor module was developed from off-the-shelf components. This module consists of a sensor device, microcontroller, ADC and RF transmitter. The integration of these components is described in detail. Deployment details and some preliminary results are presented. / by Sivaram M.S.L. Cheekiralla. / S.M.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 1997. / Includes bibliographical references (leaves 86-92). / by Vincenzo Losito. / M.S.