Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 8 of 8
Full-Text Articles in Engineering
Spatiotemporal Analysis Of Taxi And Transportation Network Companies (Tnc) Demand In The Wake Of Covid-19, Dewan Ashraful Parvez
Spatiotemporal Analysis Of Taxi And Transportation Network Companies (Tnc) Demand In The Wake Of Covid-19, Dewan Ashraful Parvez
Electronic Theses and Dissertations, 2020-
The objective of the thesis is to understand the factors affecting spatiotemporal ridehailing demand patterns as the COVID-19 pandemic has evolved. Specifically, the current study examines the key contributing factors of weekly ridehailing demand by employing Taxi and Transportation Network Companies (TNC) trip data from January 2019 through December 2020 for New York City. The ridehailing demand is partitioned across four time periods including Morning Peak, Morning Off Peak, Evening Peak and Evening Off Peak to accommodate for the time-of-day specific variations. Drawing on the high-resolution NYC data, the current study developed pooled spatial panel models to accommodate for the …
Analysis Of Shear Failure In Ultra-High Performance Concrete Beams, Kevin Conway
Analysis Of Shear Failure In Ultra-High Performance Concrete Beams, Kevin Conway
Electronic Theses and Dissertations, 2020-
Ultra-high performance concrete (UHPC) is an emerging cementitious material type currently undergoing research in different structural applications. This material is characterized by a compressive strength of 150 MPa (22 ksi), according to the Association Francaise de Genie Civil and the Federal Highway Administration, high tension strength, and high durability. Additionally, UHPC consists of secondary reinforcement in the form of steel or polymeric fibers, which enable UHPC to exhibit tension hardening behavior and tension ductility previously ignored in conventional concrete mixes. Previous research has focused on applications in the transportation and bridge design industries; however, applications in buildings and other heavy …
Ground Movements And Nonlinear-Inelastic Response Of Buildings Induced By Excavations In Glacial Clay Deposits, A. Felipe Uribe-Henao
Ground Movements And Nonlinear-Inelastic Response Of Buildings Induced By Excavations In Glacial Clay Deposits, A. Felipe Uribe-Henao
Electronic Theses and Dissertations, 2020-
The analysis of ground movements and nonlinear response of buildings induced by excavations in glacial clay deposits is conducted using finite element models built in PLAXIS2D and OpenSees. PLAXIS2D was used to simulate the performance of an urban cofferdam excavation braced with a concrete bracing system. Measured ground movements were compared with the computed response, and the influence of the temperature, installation, and curing effects on the concrete bracing is evaluated. Concrete time-dependent effects contributed to 32% of the maximum lateral wall movements. The numerical studies are expanded in a second finite element analysis to characterize the coupled fluid-solid response …
Seismic Soil-Structure Interaction Effects In Tall Buildings Considering Nonlinear-Inelastic Behaviors, Jaime Mercado
Seismic Soil-Structure Interaction Effects In Tall Buildings Considering Nonlinear-Inelastic Behaviors, Jaime Mercado
Electronic Theses and Dissertations, 2020-
Soil-structure interaction (SSI) effects are relevant for the seismic analysis of tall buildings on shallow foundations since the dynamic behavior of structures is highly affected by the interaction between the superstructure and supporting soils. As part of earthquake-resistant designs of buildings, considering SSI effects in the analysis provides more realistic estimates of its performance during a seismic event, particularly when both the structure and soil undergo large demands that can compromise serviceability. Oversimplifications of structural or soil modeling in the analysis introduces variability and biases in the computed seismic response. The main goal of this dissertation is to investigate the …
Numerical Analysis On The Geomechanical Mechanisms And Stability Of Sinkholes In Central Florida, Moataz Soliman
Numerical Analysis On The Geomechanical Mechanisms And Stability Of Sinkholes In Central Florida, Moataz Soliman
Electronic Theses and Dissertations, 2020-
Sinkholes are a common geohazard in karst areas that can threaten human life and causes significant damage to infrastructure. Approximately 18% of the United States falls into karst area where overburden soils are underlain by soluble carbonate rocks. In Florida, sinkhole-related insurance claims between 2006 and the third quarter of 2010 amounted to $1.4 billion according to the Florida Office of Insurance Regulation. Effective methods and tools for the sinkhole detection and characterization are necessary. Numerical analysis can play an important role in determining the stability of sinkholes and understanding the failure mechanism under varied subsurface geological conditions. In this …
Compressibility Of Fine-Grained Soil In Central Florida, Andre Kruk
Compressibility Of Fine-Grained Soil In Central Florida, Andre Kruk
Electronic Theses and Dissertations, 2020-
Fine-grained soils are responsible for most site settlements through a time dependent process known as consolidation. The magnitude of consolidation is quantified with three terms: the recompression and compression indices, referred to as the soil's compressibility indices, and preconsolidation pressure. The ideal methods to estimate these parameters are direct measurements from lab or in-situ field tests, other method include estimation from experience or from correlations to soil parameters. This study refines correlations between compressibility indices and index properties as previously researchers and soil mechanics suggest a strong correlation exists. This study also suggests a correlation to CPT parameters as this …
Subsurface Characterization Of Internally Eroded Soils In Karst Using The Cone Penetration Test, Ryan Shamet
Subsurface Characterization Of Internally Eroded Soils In Karst Using The Cone Penetration Test, Ryan Shamet
Electronic Theses and Dissertations, 2020-
Sinkholes are a major geohazard with life-threatening consequences when not properly detected and mitigated. Geologic conditions comprised of soluble bedrock (e.g., limestone or other carbonate-based lithologies) overlain by fine-grained sandy and clayey soils, are known internationally as "karst topography" and is generally characterized by such sinkholes, caves, sinking streams, and highly variable groundwater flow conditions. Karst sinkholes, however, are complex geohazards and are difficult to precisely characterize through geotechnical considerations alone. Deterministic methods (e.g., analytical and numerical solutions) may provide for a more robust analysis of internal soil erosion (known as soil raveling) but have limitations for the practical use …
Seismic Design Optimization Of Steel Structures Using Genetic Algorithm, Tiancheng Wang
Seismic Design Optimization Of Steel Structures Using Genetic Algorithm, Tiancheng Wang
Electronic Theses and Dissertations, 2020-
Current seismic codes do not incorporate a well-established methodology for the selection of passive dampers type and their topological distribution and properties along the height of structures. Achieving the intended performance is made more complicated when structures are subject to extreme events and operate well within their inelastic range. This thesis utilizes a self-organizing genetic algorithm (soGA) with probabilistic gene-by-gene crossover and an adaptive active ground motion subset scheme to efficiently find optimal designs of low-rise steel frames subject to large number of extreme ground motions. Different types of passive dampers were considered, while the steel frames were modeled using …