Civil and Environmental Engineering Commons^™

Modeling Of Soybean Under Present And Future Climates In Mozambique, Manuel António Dina Talacuece, Flávio Barbosa Justino, Rafael De Ávila Rodrigues, Milton Edgar Pereira Flores, Jéssica Garcia Nascimento, Eduardo Eduardo Santos

Daugherty Water for Food Global Institute: Faculty Publications

This study aims to calibrate and validate the generic crop model (CROPGRO-Soybean) and estimate the soybean yield, considering simulations with different sowing times for the current period (1990–2013) and future climate scenario (2014–2030). The database used came from observed data, nine climate models of CORDEX (Coordinated Regional climate Downscaling Experiment)-Africa framework and MERRA (Modern Era Retrospective-Analysis for Research and Applications) reanalysis. The calibration and validation data for the model were acquired in field experiments, carried out in the 2009/2010 and 2010/2011 growing seasons in the experimental area of the International Institute of Tropical Agriculture (IITA) in Angónia, Mozambique. The yield …

Identification Of Streamflow Changes Across The Continental United States Using Variable Record Lengths, Kazi Tamaddun, Ajay Kalra, Sajjad Ahmad

Civil and Environmental Engineering and Construction Faculty Research

The study focused on investigating the presence of change patterns in 600 unimpaired streamflow stations across the continental U.S. at different time intervals to understand the change patterns that can provide significant insight regarding climate variability and change. Each station had continuous streamflow data of at least 30 years (the entire dataset covered a range of 109 years). Presence of trends and shifts were detected in water year and the four seasons (fall, winter, spring, and summer) analyzing the water year and seasonal mean flows. Two non-parametric tests, namely, the Mann-Kendall test and the Pettitt’s test were used to identify …

An Investigation Of Motor Vehicle Driver Inattention And Its Effects At Highway–Rail Grade Crossings, Shanshan Zhao

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

The relationship between accident injury severity and drivers’ inattentive behavior requires an in-depth investigation – this is especially needed in the case of motor vehicle drivers at highway-rail grade crossings (HRGCs). The relationship between drivers’ personality/ socioeconomic characteristics and inattentive behavior at HRGCs is another topic requiring research. Past educational programs about safe driving at HRGCs have often not been designed to target people who may be in urgent need of such information, which may limit the effectiveness of those programs.

This dissertation thus focuses on the following four objectives: to investigate the association between motor vehicle inattentive driving and …

An Investigation In Construction Cost Estimation Using A Monte Carlo Simulation, Jeffrey D. Buchholtz

Theses and Dissertations

The Air Force estimates military construction (MILCON) costs early in a project’s development as a part of the funding approval process. However, many of the initial cost estimates deviate significantly more than expected from the actual project costs, hindering funding allocation efforts. There is a need for improved estimation techniques. This research examines a cost estimation model for the initial programming stages of a project when only general scope information is available.

This study develops a Monte Carlo simulation based on historical construction cost data to predict project costs base on facility type. For a given facility type, the research …

Renovation Of El Camino Real Of Santa Clara, Thao Nguyen-Pham, John Garzee

Civil, Environmental and Sustainable Engineering Senior Theses

In this project we focus on a section of the El Camino Real that is a major corridor that connects the South Bay to much of the Peninsula. The portion that we are looking at is by Santa Clara University from Lafayette Street to Scott Boulevard which consists of 3lanes in both directions. This is much wider than sections farther north as there are much higher traffic volumes in the spread out South Bay. As a result, El Camino Real can be dangerous for pedestrians and cyclists. Along with pedestrian safety concerns, our project goes into the inadequate service levels …

Forest Soil Carbon And Nitrogen Cycles Under Biomass Harvest: Stability, Transient Response, And Feedback, Anthony J. Parolari, Amilcare Porporato

Civil and Environmental Engineering Faculty Research and Publications

Biomass harvest generates an imbalance in forest carbon (C) and nitrogen (N) cycles and the nonlinear biogeochemical responses may have long-term consequences for soil fertility and sustainable management. We analyze these dynamics and characterize the impact of biomass harvest and N fertilization on soil biogeochemistry and ecosystem yield with an ecosystem model of intermediate complexity that couples plant and soil C and N cycles. Two harvest schemes are modeled: continuous harvest at low intensity and periodic clear-cut harvest. Continuously-harvested systems sustain N harvest at steady-state under net mineralization conditions, which depends on the C:N ratio and respiration rate of decomposers. …

Regional Wastewater Facility Systems Design, Sage Aoki, Joseph Calvo, Kayden Haleakala, Steward Yang

Civil, Environmental and Sustainable Engineering Senior Theses

The San José-Santa Clara Regional Wastewater Facility (RWF) was constructed in 1956 as a primary water treatment plant. Secondary treatment facilities were constructed in 1964 in response to a growing population and economy along with state regulations. The RWF expanded to tertiary treatment in 1979 to meet Clean Water Act regulations. A wet weather headworks facility was commissioned in 2008, and in 2011 the gaseous chlorine/sulfur dioxide system for disinfection was converted to a sodium hypochlorite/sodium bisulfate system in 2011 (RWF 2015). The RWF launched a Capital Improvement Program (CIP) in 2014, identifying 33 capital projects. The Facility Wide Water …

Nicaragua Water Distribution System, Leah Bensching, Jamie Monk

Civil, Environmental and Sustainable Engineering Senior Theses

In developing nations, such as Nicaragua, water security issues affect a large portion of the population. A lack of clean and secure water negatively causes many public health, environmental and economic concerns. This project addresses the need to develop a water distribution system to a rural community in Nicaragua. The proposed solutions will allow the community to choose more resilient design options to ensure reliable water delivery throughout the community.

By using NeatWork, a Nicaraguan based system, and WaterGEMS, which is more commonly used in the United States, it was determined that designing for 100% reliability was the most responsible …

24th National Timber Bridge Design Competition, Marie Mcnamara, Andrew D. Porter, Sarah Martina Sbicca

Civil, Environmental and Sustainable Engineering Senior Theses

For the 2016 Senior Design project, our team elected to design and construct a short-span pedestrian bridge for the 24th National Timber Bridge Design Competition. The competition was sponsored by the Southwest Mississippi RC&D council (SMRCD) of the Forest Products Society in association with the American Society of Civil Engineers. There were a number of different design and testing requirements to abide by, including both competition regulations as well as AASHTO guidelines pertaining to the construction of pedestrian bridges. [1] A great deal of diligence was taken to assure that our team performed well in the competition; every rule and …

Rise Above The Flood: Bridge Building In Gambibgo, Ghana, Vanessa Diaz, Ariana Govan, Matthew Millsaps

Civil, Environmental and Sustainable Engineering Senior Theses

This thesis focuses on the design of a steel girder bridge for a rural community in Ghana, Africa. While Santa Clara Civil Engineering Senior Design Teams have been working in this community since 2008, it was not until 2013 that a project team attempted to design a pedestrian footbridge. After the 20152016 project team decided to take on the project, it became clear from talking with the Ghanaian Municipal Engineers and local community members that the steel suspension bridge proposed by the 2013 team would not meet all the needs of the community. Therefore, the team redesigned the bridge, proposing …

Foundation Design For Multistory Building In Oakland, Sean Cain

Civil, Environmental and Sustainable Engineering Senior Theses

This project focuses on the design of a foundation and garage-level retaining walls for a 25 story building in Oakland, California. The design was completed through the use of data from a 1988 soil investigation and provided structural loads. The site is composed of a thin sand layer above a clay layer about 400 feet thick. Analysis included soil and groundwater conditions and exploration of spread footings, mat footings, and pile foundations. The final selected foundation type is driven piles with the other options discarded due to lack of data and an unsuitability for the structure requirements. Piles are suitable …

Redesign Of Lawrence Expressway And Pruneridge Avenue, Matthew Wong, Tyler Isaac

Civil, Environmental and Sustainable Engineering Senior Theses

In 2012, the segment of Pruneridge Avenue from Lawrence Expressway to Pomeroy Avenue saw a project called a Road Diet. A Road Diet refers to the replacement of vehicle lanes with bicycle lanes and a center turning lane, in order to create safe zones for cyclists and drivers on the same street. While the Road Diet sufficiently addressed the safety issues of the corridor, it severely worsened its traffic capacity, creating long queues along Pruneridge and on Lawrence Expressway during peak traffic hours as residents around the area commute to and from work. The queues are so long that many …

Analysis Of Brazilian Split Cylinder Using The State Based Peridynamic Lattice Model, Shreya Vemuganti

Civil Engineering ETDs

Concrete members deform discontinuously in the form of cracks and fracture. Continuum mechanics, which has dominated the field of solid mechanics over the years, does not handle such discontinuities. A material, as defined by continuum mechanics is that which is continuous and fills the space it occupies. Although this is a reasonable assumption for metals, it is an unrealistic notion for concrete. Stewart Silling invented peridynamics, which involves nonlocal solid modelling upon a continuous material space. Walter Gerstle developed a practical application of the peridynamic model for solid mechanics called the state-based peridynamic lattice model (SPLM). This approach involves material …

On Cross-Anisotropy Of Flexible Pavement Layer Materials For Improved Pavement Responses, Mesbah Ahmed

Civil Engineering ETDs

Pavement layer materials are typically assumed to be isotropic in determining pavement responses, such as stress and strain. The main benefit of the isotropic assumption is that stiffness defined by modulus of elasticity (E-value) is equal in all directions. In reality, stiffness along vertical and horizontal (i.e., and ) may vary due to density gradients in compacted layer materials caused by vertical compaction during construction. Therefore, pavement layer materials with different vertical and horizontal modulus (i.e., \u2260 ) are cross-anisotropic. Past studies have reported that degree of cross-anisotropy, ( ) ranges from 0.2 to 0.85 in Asphalt Concrete (AC) layers. …

Risk Assessment Of Post-Fire Floods On Dams And Their Floodplains, Krishna Chaitanya Jagadeesh Simma

Civil Engineering ETDs

The rapidly changing global climate and the increased dependence on infrastructure networks make our society vulnerable to natural disasters. Decision makers need to understand the intensity of potential natural disasters to take necessary actions to minimize their impacts. In Southwest United States, wildfires are increasing in frequency and magnitude. The literature review shows limited studies in evaluating the impacts of post-wildfire floods on civil infrastructures and residential zones. Earth dams are vulnerable to post-wildfire floods. The increased post-wildfire runoff volumes due to changes in soil characteristics and reduced vegetation could result in overtopping failure of an earth dam (dam-break scenario), …

On The Flux Richardson Number In Stably Stratified Turbulence, Subhas K. Venayagamoorthy, Jeffrey R. Koseff

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The flux Richardson number Rf (often referred to as the mixing efficiency) is a widely used parameter in stably stratified turbulence which is intended to provide a measure of the amount of turbulent kinetic energy k that is irreversibly converted to background potential energy (which is by definition the minimum potential energy that a stratified fluid can attain that is not available for conversion back to kinetic energy) due to turbulent mixing. The flux Richardson number is traditionally defined as the ratio of the buoyancy flux B to the production rate of turbulent kinetic energy P. An alternative generalized definition …

Habitat For Humanity Apartment Complex Redesign, Megan August, Molly Bencomo, Ashley Waite

Civil, Environmental and Sustainable Engineering Senior Theses

This project consists of the redesign of a three-story apartment complex for Habitat for Humanity that will be constructed in Walnut Creek, CA in 2017. A project in Fremont, CA served as the basis for the design. However, the height of the complex in Fremont exceeded the Walnut Creek Building Code height limitations, making the redesign of this timber structure necessary. The challenge was to reduce the structural space between stories to 9.5 inches in order to achieve comfortable interior clearances and meet the City of Walnut Creek’s height restriction. The structural components for Building Type A in the Las …

Quantitative Risk Evaluation Of Obstacle Limitation Surfaces For Final Approaches At Airports, Amila Silva, Alexandre G. De Barros

Journal of Aviation Technology and Engineering

Obstacle limitation surfaces (OLS) are the main safeguard against objects that can pose a hazard to aircraft operations at and around airports. The standard dimensions of the most of those surfaces were estimated using the pilot’s experience at the time when they were included in the standard documents. As a result, some of these standards may have been overestimated, while others may not provide an adequate level of safety. With airports moving to the Safety Management System (SMS) approach to design and operations safety, proper evaluation of the level of safety provided by OLS at specific sites becomes important to …

Probability Model Of Corrosion-Induced Cracking Time In Chloride-Contaminated Reinforced Concrete, Chunhua Lu, Jinmu Yang, Ronggui Liu

International Conference on Durability of Concrete Structures

Corrosion-induced concrete cover cracking caused by chloride ion is an important indication of durability limit state for marine reinforced concrete (RC) structures and can ultimately determine the structural service life. In this paper, considering the random nature of factors affecting the corrosion cracking process, a probabilistic model which expands on the deterministic model of cover cracking time is developed by using Monte Carlo simulation technique. The results showed that the time to corrosion cracking can be modelled by the Weibull distribution. Finally, the probabilistic analysis for the cracking time is applied to an in-site RC bridge girder with four different …

Progress Of Carbonation In Chloride Contaminated Concretes, Yaocheng Wang, P. A.M. Basheer, S. Nanukuttan, Y. Bai

International Conference on Durability of Concrete Structures

Concretes used in marine environment are generally under the cyclic effect of CO₂ and chloride ions (Cl^-). To date, the influence of carbonation on ingress of chloride ions in concretes has been widely studied; in comparison, study on the influence of Cl^- on the progress of carbonation is limited. During the study, concretes were exposed to independent and combined mechanisms of carbonation and chloride ingress regimes. Profiles of apparent pH and chloride concentration were used to indicate the progress of carbonation and ingress of Cl^- in concretes. From the apparent pH profile, a carbonation front …

Carbon Fiber As Anode Material For Cathodic Prevention In Cementitious Materials, Emma Qingnan Zhang, Luping Tang, Thomas Zack

International Conference on Durability of Concrete Structures

Cathodic prevention (CPre) technique is a promising method and has been used for the past two decades to prevent steel from corrosion in concrete structures. However, wide application of this technique has been restricted due to high costs of anode materials. In order to lower the cost and further improve this technique, carbon fiber composite anode has been introduced as an alternative anode material with affordable price and other outstanding properties. This paper presents the study of using carbon fiber mesh as anode material for long-term cathodic prevention system and the effect of accelerated current on macro- and microstructure of …

Investigation Of A Novel 3d Non-Destructive Evaluation For Corrosion Process In Reinforced Concrete, Guohao Fang, Biqin Dong, Ningxu Han, Feng Xing

International Conference on Durability of Concrete Structures

X-ray computed microtomography (X-ray μCT) method is proposed to trace the corrosion features of steel bar in cementitious materials. Three-dimensional corrosion morphology (including morphology of steel corrosion, corrosion products and cracks formation) are characterized and reconstructed. Experimental results demonstrate that X-ray μCT can track time-dependent development of corrosion products and the subsequent initiation and propagation of corrosion-induced cracks. In addition, scanning electron microscope (SEM) and energy dispersive spectrometer (EDS) are used to morphologically and chemically analyze the corrosion result. The microscopic analysis result is found to be in a very good agreement with the image analysis measured by X-ray μCT. …

An Experimental Study On Effect Of Steel Corrosion On The Bond–Slip Performance Of Reinforced Concrete, Xiaolin Zhang, Xuebing Liang, Hancheng Huang, Haijun Zhou

International Conference on Durability of Concrete Structures

This paper studied the effects of reinforcement corrosion on bond performance between rebar and concrete. Tests were carried out to evaluate the degradation of bond between reinforcing steel and concrete for different corrosion levels of reinforcing steel. A series of 20 specimens of different concrete strength with various reinforcing steel corrosion levels were designed and manufactured. Each specimen was casted as a 200-mm concrete cube, and a steel rebar was centrally embedded with two stirrups around it. The steel rebar were corroded using an electrochemical accelerated corrosion technique. The corrosion crack opening width and length were recorded after the corrosion …

Threshold Chloride Concentration Of Stainless Steels In Simulated Concrete Pore Solution, Hailong Wang, Jiayan Ling, Xiaoyan Sun

International Conference on Durability of Concrete Structures

To evaluate whether stainless steel can replace carbon steel as rebar in reinforced concrete structures exposed to aggressive environment, the threshold chloride concentration of carbon steel, austenitic and duplex stainless steels were experimentally studied in this paper. The solutions with pH ranging from 9.5 to 13.6 were used herein to simulate the pore liquids in both alkaline and carbonated concretes. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) tests were carried out in the solutions with chloride concentration ranging from 0 to 5.0M and at a temperature around 25°C. The activation of pitting corrosion was determined when corrosion current increased and …

Corrosion-Induced Concrete Cracking Model Considering Corrosion-Filled Paste, Jianfeng Dong, Yuxi Zhao, Yingyao Wu, Weiliang Jin

International Conference on Durability of Concrete Structures

A T_CP–T_CL model is established to describe the relationship between the thickness of the corrosion-filled paste (CP) and that of the corrosion layer (CL). This model can describe the phenomenon that the corrosion filling in the concrete pores and accumulating at the steel/concrete interface occur synchronously. Based on the T_CP–T_CL model, a corrosion-induced concrete cracking model, which can quantitatively consider corrosion-filled paste at concrete/steel interface, is proposed. Combined with damage analysis in corrosion-induced cracking process of concrete cover, the model is developed to describe the quantity of steel corrosion required to crack …

The Compressive Strength Of Cement–Slag–Calcium Sulphoaluminate Ternary System, Hu Shi, Jun Wang, Zhuqing Yu, Xiaodong Shen

International Conference on Durability of Concrete Structures

At present, there is an increasing interest on the use of calcium sulphoaluminate (C₄A₃$) in cement. In this paper, pure mineral of sulphoaluminate (C₄A₃$) was prepared in laboratory. Different dosages of steel slag and C₄A₃$ were blended into cement. The aim of this paper is to investigate the compressive strength of this ternary system. The test results show that the addition of C₄A₃$ can improve the strength of cement. Larger C₄A₃$ dosage (7%) may reduce the 28 days strength. The …

Potential For Alkali–Silica Reaction In Radiation Shielding Concrete Containing Special Aggregates, Daria Jóźwiak-Niedźwiedzka, Michał A. Glinicki, Karolina Gibas

International Conference on Durability of Concrete Structures

In the present study, the potential for the alkali–silica reaction (ASR) in radiation shielding concrete containing special aggregates is presented. The tests were performed on two kinds of aggregate: (1) high-density aggregate to absorb the gamma radiation (barite, magnetite, and hematite) and (2) mineral with high bound water content to attenuate the neutron flux (serpentinite). The optical microscopy in transparent light on thin sections, XRD and XRF method, was used to assess the mineral composition of aggregates. ASTM C1260 test method for potential alkali reactivity of aggregates was applied also to investigate the effect of different content and crystal size …

Effect Of Superabsorbent Polymers (Sap) On Fresh State Mortars With Ground Granulated Blast-Furnace Slag (Ggbs), Fernando Do Couto Rosa Almeida, Agnieszka Joanna Klemm

International Conference on Durability of Concrete Structures

Although cementitious materials are the main construction materials and worldwide produced, there is still a major concern about their sustainability and durability, especially in terms of conserving resources, reducing wastes, and decreasing the environmental impacts of repair and replacement. In general, cementitious materials are very susceptible to cracking provoked by autogenous shrinkage due to their associated self-desiccation process. The problem is even more critical in concrete with blended cements, including Portland cement with ground granulated blast-furnace slag (GGBS). The current paper evaluates efficiency of superabsorbent polymers (SAP) as internal curing agents; shrinkage reduction in mortars with different levels of cement …

Designing Repeatable Self-Healing Into Cementitious Materials, Mo Li, Shuai Fan

International Conference on Durability of Concrete Structures

Designing self-healing into cementitious materials can open a new world of opportunities for resilient concrete infrastructure under service loading conditions. The self-healing process should be robust as well as repeatable, allowing for self-repair after multiple damage events. The repeatability poses great challenges when self-healing strategies mainly rely on the formation of low-strength calcium carbonate healing product, complicated by the localized cracking behavior of cementitious materials. This study aims at formulating a new cementitious material system with designed physical and chemical characteristics that favour repeatable self-healing. Advanced experimental methods, coupled with micromechanics theory, are adopted to probe and design repeatable self-healing …

Progress In Durability Study Of Frp Materials, Zeng-Zhu Zhu, Ying-Wu Zhou, Li-Li Sui, Feng Xing, Jia Du

International Conference on Durability of Concrete Structures

During the past decades, FRP strengthened RC structures have attracted worldwide interest in both application and research. Nowadays, as more and more infrastructures are being suffered from severe corrosions due to harsh and extreme environments, the durability of FRP strengthened RC structures has generally emerged as the most important issue in research. Thus, the paper presents the latest progress in durability study of the FRP materials through an in-depth review and analysis on existing extensive investigations. The time-dependent performances of two types of FRP materials of carbon FRP (CFRP) and glass FRP (GFRP) under severe environments of humidity, high temperature, …