Civil Engineering Commons^™

Risk-Based Decision Making Support For Construction Corporate Resource Management, Reza Sheykhi

FIU Electronic Theses and Dissertations

Competitive bidding typically challenges contractors to stay in business by reducing contingency and limiting profit margin, which imposes more prudent resource utilization and allocation decisions during both planning and construction phases of projects. Many of these decisions must be made considering uncertainties that affect resource production and construction performance through several factors such as weather, managerial practices, job-type, and market conditions, etc. Construction decision makers will therefore have varied approaches to deal with these uncertainties based on their risk utility or perception. This research presents the development of a model for investigating the impact of risk-based approaches on construction network …

Water Quality Modelling Using Multivariate Statistical Analysis And Remote Sensing In South Florida, Mohammad Hajigholizadeh

FIU Electronic Theses and Dissertations

The overall objective of this dissertation research is to understand the spatiotemporal dynamics of water quality parameters in different water bodies of South Florida. Two major approaches (multivariate statistical techniques and remote sensing) were used in this study. Multivariate statistical techniques include cluster analysis (CA), principal component analysis (PCA), factor analysis (FA), discriminant analysis (DA), absolute principal component score-multiple linear regression (APCS-MLR) and PMF receptor modeling techniques were used to assess the water quality and identify and quantify the potential pollution sources affecting the water quality of three major rivers of South Florida. For this purpose, a 15-year (2000–2014) data …

The Impacts Of Telecommuting On The Time-Space Distribution Of Daily Activities, Mario Benito Rojas Iv

FIU Electronic Theses and Dissertations

As major cities have aged, they have also met or exceeded their transportation infrastructure’s capacity. This has led to many negative impacts such as increased greenhouse gas emissions, delay, travel time, congestion, as well as decreased energy independence, standard of living for the cities’ inhabitants and the world as a whole. As a result, these cities will undoubtedly suffer and will struggle to meet the needs of their citizens. It is becoming more evident, and relevant, that the solution to today’s and tomorrow’s transportation problems will be overcome through the use of policy as well as innovative strategies, one of …

A Framework For Recommending Signal Timing Improvements Based On Automatic Vehicle Matching Technologies, Xuanwu Chen

FIU Electronic Theses and Dissertations

Continuously monitoring and automatically identifying existing problems in traffic signal operation is a challenging and time-consuming task. Although data are becoming available due to the adoption of emerging detection technologies, efforts on utilizing the data to diagnose signal control are limited. The current practices of retiming signals are still periodic and based on several days of aggregated turning movement counts. This dissertation developed a framework of automatic signal operation diagnosis with the aim to support decision-making processes by assessing the signal control and identifying the signal retiming needs. The developed framework used a combination of relatively low-cost data from Wi-Fi …

Evaluation Of Redundancy Of Twin Steel Box-Girder Bridges, Huy V. Pham

FIU Electronic Theses and Dissertations

Based on the definition given in the AASHTO LRFD Bridge Design Specifications, twin steel box-girder bridges are classified as bridges with fracture critical members (FCMs), in which a failure of a tension member is expected to lead to a collapse of the bridge. However, a number of such bridges with either a partial or full-depth crack in one girder have been reported and are still providing service without collapsing. The main objective of this research project is to understand the behavior of twin steel box-girder bridges and to develop methods for evaluating their redundancy level in the event of the …

A System-Of-Systems Framework For Assessment Of Resilience In Complex Construction Projects, Jin Zhu

FIU Electronic Theses and Dissertations

Uncertainty is a major reason of low efficiency in construction projects. Traditional approaches in dealing with uncertainty in projects focus on risk identification, mitigation, and transfer. These risk-based approaches may protect projects from identified risks. However, they cannot ensure the success of projects in environments with deep uncertainty. Hence, there is a need for a paradigm shift from risk-based to resilience-based approaches. A resilience-based approach focuses on enhancing project resilience as a capability to cope with known and unknown uncertainty. The objective of this research is to fill the knowledge gap and create the theory of resilience in the context …

Database-Assisted Analysis And Design Of Wind Loads On Rigid Buildings, Filmon Fesehaye Habte

FIU Electronic Theses and Dissertations

The turbulent nature of the wind flow coupled with additional turbulence created by the wind-building interaction result in highly non-uniform, fluctuating wind-loading on building envelopes. This is true even for simple rectangular symmetric buildings. Building codes and standards should reflect the information on which they are based as closely as possible, and this should be achieved without making the building codes too complicated and/or bulky. However, given the complexity of wind loading on low-rise buildings, its codification can be difficult, and it often entails significant inconsistencies. This required the development of alternative design methods, such as the Database-Assisted-Design (DAD) methodology, …

Analyzing Decision Making In Alternative Contracting For Highway Pavement Rehabilitation Projects, Mohamed Ibrahim

FIU Electronic Theses and Dissertations

The negative impacts associated with highway pavement rehabilitation projects drove state highway agencies (SHAs) towards increased adoption of alternative contracting methods (ACMs) to accelerate the construction of such projects; hence, reducing these impacts on the travelling public. However, the application of such methods showed mixed results due to the lack of specific guidelines addressing the adoption of such methods and the selection of the best ACM for each project. This lack of guidelines stems from the lack of research studies examining the impact of each of these methods on the time/cost trade-off relationship in highway rehabilitation projects. Existing literature includes …

Hydrogeochemical Modeling Of Saltwater Intrusion And Water Supply Augmentation In South Florida, Yonas T. Habtemichael

FIU Electronic Theses and Dissertations

The Biscayne Aquifer is a primary source of water supply in Southeast Florida. As a coastal aquifer, it is threatened by saltwater intrusion (SWI) when the natural groundwater flow is altered by over-pumping of groundwater. SWI is detrimental to the quality of fresh groundwater sources, making the water unfit for drinking due to mixing and reactions with aquifer minerals. Increasing water demand and complex environmental issues thus force water utilities in South Florida to sustainably manage saltwater intrusion and develop alternative water supplies (e.g., aquifer storage and recovery, ASR).

The objectives of this study were to develop and use calibrated …

On The Role Of The Pore Water Chemistry Of Deficient Post-Tension Grout To Promote Steel Corrosion, Samanbar Permeh

FIU Electronic Theses and Dissertations

Corrosion failure of post-tension tendons with pre-packaged thixotropic grout was documented in Florida Bridges in less than 10 years of service. Analysis of deficient grout in Florida post-tensioned (PT) bridges where severe corrosion developed indicated enhanced sulfate ion concentration, high pore water pH, enhanced moisture and low chloride content. The corrosion wasn’t consistent with the conventional causes of steel corrosion such as bleed water accumulation in grout void spaces, chloride contamination and pore water carbonation. Corrosion development was associated with deficient grout with enhanced sulfate levels. However, limited information is available on the corrosion behavior of PT strand in grout …