Civil Engineering Commons^™

Biaxial Bending And Lateral-Torsional Instability Of Imperfect Frp I-Beams Including Effects Of Retrofitting, Jodi Marie Knorowski

Civil & Environmental Engineering Theses & Dissertations

This thesis presents the outcome of a theoretical and experimental study of the behavior of Fiber Reinforced Polymer (FRP) I-beams susceptible to lateral-torsional instability or when subjected to biaxial bending. Laboratory experiments involved application of vertical and horizontal static loads to a 4 x 4 x ¼ in. I-beam with various lengths, and the resulting displacement, twist, and strain were recorded. In the vertical direction, the beam was loaded from different reference load heights with respect to the shear center of the beam. The governing biaxial flexure and torsion differential equations were modified to account for the presence of initial …

Demand Responsive Signal Control Strategy (Drsc) Incorporating Queue Length Information In Real-Time Signal Control, Rahul Rajbhara

Civil & Environmental Engineering Theses & Dissertations

Most of the existing vehicle detection systems, namely inductive loops, video cameras etc. are incapable of measuring the queue lengths at signalized intersections. However, with the advent of modern technology, newer detection methods such as probe vehicles equipped with wireless communications (Connected Vehicles), particularly under the Vehicle Infrastructure Integration [52), and radar detection currently provide this capability [53). This thesis presents a Demand Responsive Signal Control Strategy (termed as DRSC) for an isolated signalized intersection. The control strategy incorporates real-time queue length information (obtained from probe vehicles) into the signal control logic. Demand based maximum green time for each upcoming/new …

Probabilistic Resilience Quantification And Visualization Building Performance To Hurricane Wind Speeds, Berna Eren Tokgoz

Engineering Management & Systems Engineering Theses & Dissertations

Natural and man made disasters are unpredictable and unavoidable in today's world. Their frequency of occurrence and damages keep increasing. Due to the efforts to reduce negative consequences from such disasters, the concept of resilience has gained so much popularity in disaster management area especially after disasters like the September 11 attacks and Hurricane Katrina. Complex systems of today are under operational risks because of increasing threats and their high level of vulnerability. Hence, such systems need to adapt the concept of resilience for continuous operations. Resilience is a proactive concept which should incorporate both pre-event (preparedness and mitigation) and …

Efficient Stand-Alone Generalized Inverse Algorithms And Software For Engineering/Sciences Applications: Research And Education, Subhash Chandra Bose S V Kadiam

Civil & Environmental Engineering Theses & Dissertations

Efficient numerical procedures for finding the generalized (or pseudo) inverse of a general (square/rectangle, symmetrical/unsymmetrical, non-singular/singular, real/complex numbers) matrix and solving systems of Simultaneous Linear Equations (SLE) are formulated and explained. The developed procedures and its associated computer software (under MATLAB computer environment) have been based on "special Cholesky factorization schemes" (for a singular matrix), the generalized inverse of the matrix product, and were further enhanced by the Domain Decomposition (DD) formulation.

Test matrices from different fields of applications have been chosen, tested and compared with other existing algorithms. The results of the numerical tests have indicated that the developed …

Static And Impact Load Response Of Reinforced Concrete Beams And Slabs With Nsm-Cfrp Retrofitting, Nakul Ramanna-Sanjeevaiah

Civil & Environmental Engineering Theses & Dissertations

The use of Near-Surface Mounted Carbon Fiber Reinforced Polymer (NSM-CFRP) reinforcement such as carbon FRP strips holds a high potential for increasing the flexural strength of reinforced concrete members. In comparison to externally bonded CFRP laminates, NSM-CFRP reinforcement approach has several advantages. The main advantages include increased stiffness and strength, better bonding, the possibility of anchoring the reinforcement into adjacent members, and minimal installation time. Thus, the structural engineers worldwide are developing a considerable interest in practical applications of the NSM-CFRP reinforcement technique. A considerable amount of research is still needed in order to fully benefit from this method not …

Integrating Probe Vehicles And Stationary Detector Data To Construct Accurate Cumulative Curves To Study Bottlenecks, Khairul Azfi Anuar

Civil & Environmental Engineering Theses & Dissertations

Advancements in sensors technologies have given researchers and practitioners access to an immense amount of traffic data from multiple types of sensors. However, because of the diversity of the data types, developing a relationship between the different data sources can be challenging. To further complicate the issue, the presence of error or noise makes it difficult to infer any reliable conclusions from the data. To develop a relationship between different data sources, a new methodology is proposed in this thesis for fusing stationary detector data and probe vehicle data to construct an accurate cumulative curve. To remove or to reduce …

The Modified Coastal Storm Impulse Parameter, Sayed Gholamreza Mahmoudpour

Civil & Environmental Engineering Theses & Dissertations

The correlation of the morphological changes to the coast and storm characteristics is among interests of coastal engineers. Better understandings of a storm's potential forces ultimately lead engineers to safer designs and minimize the damages. Therefore, a need to quantify the storm potential forces to a storm parameter is evident. The desired storm parameter is to consider all the relative physical factors and is to present realistic results that then can be proven by actual nature response.

The concept of Coastal Storm Impulse (COSI) parameter was first introduced by Basco and Klentzman (2006) and is based on the conservation of …

Analysis Of Primary-Secondary Incident Events On Urban Freeways, Hongbing Zhang

Civil & Environmental Engineering Theses & Dissertations

The objective of this study is to understand the nature of primary and secondary traffic incidents, assess their impacts and explore the implications in traffic operations, safety, and planning. To achieve the objective, a queue-based secondary incident identification method was developed and applied based on detailed incident, traffic and geometric data sets from Hampton Roads, Virginia. This identification method can overcome the limitations in earlier studies and identify secondary incidents in both road directions. An innovative event categorization defines the term "primary-secondary incident event", as one characterized by a primary incident and one or more associated secondary incidents in both …

Spatial Analysis Of Travel Behavior And Response To Traveler Information, Xin Wang

Civil & Environmental Engineering Theses & Dissertations

Transportation planners have long recognized that it is urgent to integrate emerging spatial analysis with travel behavior studies. A clearer understanding of the spatial interactions among travelers and the complex environment they face has the potential to reap benefits of the ongoing technologies of travel behavior, spatial analysis and Advanced Traveler Information Systems (ATIS).

Considering that spatial patterns have been overlooked in the literature of travel behavior and ATIS, the main objective of this research is to use robust methods of spatial analysis to enhance the understanding of how the associations between traveler decisions, built environment and socio-demographic characteristics are …

Evaluation Of Hydraulic Conductivity Of Non Aqueous Phase Liquids In Partially Saturated Soils, Chijioke Ekeleme Akamiro

Civil & Environmental Engineering Theses & Dissertations

This study seeks to investigate a problem of predicting the hydraulic conductivity of NAPLs in partially saturated soils and to relate the hydraulic conductivity to basic soil parameters that are either easy to determine or are in wide use. To evaluate hydraulic conductivity in partially saturated soils, previous researchers have focused on flow geometry, soil and chemical properties, etc. used in CHEMFLO program by Nofziger et al., (1989) and saturation equations by such authors as Van Genutchen (1980) and Brooks and Corey (1964). Among those, the soil-water characteristic curve (SWCC) is the most widely used constitutive relations for unsaturated soils …

Distribution Analysis Of Freight Transportation With Gravity Model And Genetic Algorithm, Jun Duanmu, Peter Foytik, Asad Khattak, R. Michael Robinson

VMASC Publications

The application of a gravity model in freight modeling work on both short-haul and long-haul trips is discussed. A commodity-based gravity model was developed to assess the distribution of freight by long-haul trucks in southeastern Virginia. Although gravity models have been used extensively in transportation studies, little work has been done to address the special characteristics of freight transportation, such as the definition of friction factors and the differences between long-haul and short-haul trips. Results of a recent study of these and similar problems provide valuable insight into freight distribution modeling. A new calibration method that used a genetic algorithm …

Evacuee Route Choice Decisions In A Dynamic Hurricane Evacuation Context, R. Michael Robinson, Asad Khattak

VMASC Publications

Very high traffic volumes may lead to extensive congestion during hurricane evacuations. Evacuation planners reduce this congestion by careful planning for multiple hurricane scenarios and assignment of evacuation routes and timing. This planning may be for naught if obstructions block key roadways. An advanced traveler information system (ATIS) may be used to guide evacuees to alternate routes, but how effective will that guidance be? Should the use of alternate routes be encouraged? How are drivers likely to respond to delays and information? Will information shorten or improve the reliability of travel times in emergency conditions? Integration of a dynamic evacuation …