Digital Commons Network^™

Floating Offshore Wind Turbine Project, Courtney Huitt, Cormack Williams

Civil and Environmental Engineering

Offshore wind is a developing industry in the Central Coast with the advent of the future offshore wind project planned off the north coast of San Luis Obispo County. This senior design project aligns with the recently leased wind energy project as a detailed study on the structural design, geotechnical design, and construction of a single 14 MW floating offshore wind turbine (FOWT) located 40 km NW of Morro Bay (NOAA buoy 46028). A preliminary design of a spar FOWT is presented in this project as a solution to the rapidly increasing water depth off the coast of Morro Bay, …

Evaluation Of Seismic Force Provisions For Ancillary Systems In Piers And Wharves Considering Effects Of Nonlinearity, Rakesh K. Goel

Civil and Environmental Engineering

Much of the prior research on understanding seismic response of secondary systems and development of code provisions was conducted either for nuclear power plant facilities or buildings. Most marine structures differ from nuclear power plant facilities or buildings in that the marine structures can be idealized as one-story building type systems. Furthermore, most previous studies have been limited to linear elastic behavior of both primary and secondary systems.

The objectives of this study are to (1) understand effects of nonlinearity, both in primary and secondary systems, on seismic forces in secondary systems, and (2) evaluate seismic force provisions proposed in …

Evaluation Of A Substitute Structure Method To Estimate Seismic Displacement Demand In Piers And Wharves, Rakesh K. Goel

Civil and Environmental Engineering

This paper compares seismic displacement from the MOTEMS and the ASCE/COPRI 61-14 substitute structure method (SSM) with results from the nonlinear response history analysis (NLRHA). It is found that the SSM is biased toward overpredicting displacement demand for short-period systems and under-predicting displacement demand for long-period systems. The overprediction was found to be excessive for very-short period systems (i.e., systems with periods shorter than the period at which the design spectrum transitions from linearly increasing spectral acceleration to constant spectral acceleration). It is recommended that the SSM not be used for such systems. It is also recommended that the SSM …

Seismic Forces In Ancillary Components Supported On Piers And Wharves, Rakesh K. Goel

Civil and Environmental Engineering

This paper presents a simple procedure to estimate seismic forces in ancillary components (secondary systems) supported on marine structures such as piers, wharves, and marine oil terminals (primary systems). Since many such marine structures can be idealized as single-degree-of-freedom (SDOF) systems, this study uses a simple linear-elastic model with two DOF, one representing the marine structure and the other representing the ancillary component. This study shows that acceleration at the base of the secondary system is approximately equal to spectral acceleration at the fundamental period of the primary system. It also proposes a formula, which is an improvement over current …

Environmental Engineering At Cal Poly-San Luis Obispo, Harold M. Cota

Civil and Environmental Engineering

The story recorded here began with a timeline prepared by Professor Rod Keif outlining some of the important events in the formation of the Environmental Engineering Department at Cal Poly-San Luis Obispo. He expanded the timeline and added some comments in a 5-page History of Environmental Engineering at Cal Poly in 1998 (1).

Rod Keif was a key player in the Air Conditioning and Refrigeration Engineering Department that eventually became the Environmental Engineering Department. He prepared his students to be leaders in the industry, received the Distinguished Teachers Award in 1967, and was chairman of the Academic Senate in 1969. …

Gpumap: A Transparently Gpu-Accelerated Python Map Function, Ivan Pachev, Chris Lupo

Civil and Environmental Engineering

No abstract provided.

Effects Of Nonlinearity In Primary Systems On Acceleration In Secondary Systems: Piers, Wharves, And Marine Oil Terminals, Rakesh K. Goel

Civil and Environmental Engineering

This investigation examines the effects of nonlinearity in the primary system of the coupled primary-secondary systems on accelerations in the secondary systems during seismic loading. The coupled primary-secondary systems considered in this investigation are those typically found in piers, wharves, and marine oil terminals. This investigation first examines the effects of nonlinearity in the primary system on acceleration at the point of attachment of the secondary system to the primary system and found that:  The acceleration at the point of attachment of the secodnary system to the primary system decreases with increasing level of nonlinearity in the primary system. …

Enhancing Regional Ocean Modeling Simulation Performance With The Xeon Phi Architecture, Chris Lupo, Maria Pantoja, Paul Choboter

Civil and Environmental Engineering

Ocean studies are crucial to many scientific disciplines. Due to the difficulty in probing the deep layers of the ocean and the scarcity of data in some of the oceans, the scientific community relies heavily on ocean simulation models. Ocean modeling is complex and computationally intensive, and improving the performance of these models will greatly advance and improve the work of ocean scientists. This paper presents a detailed exploration of the acceleration of the Regional Ocean Model System (ROMS) software with the latest Intel Xeon Phi x200 architectures. Both shared-memory and distributed-memory parallel computing models are evaluated. Results show run …

Taruc: A Topology-Aware Resource Utility And Contention Benchmark, Gavin Baker, Chris Lupo

Civil and Environmental Engineering

Computer architects have increased hardware parallelism and power efficiency by integrating massively parallel hardware accelerators (coprocessors) into compute systems. Many modern HPC clusters now consist of multi-CPU nodes along with additional hardware accelerators in the form of graphics processing units (GPUs). Each CPU and GPU is integrated with system memory via communication links (QPI and PCIe) and multi-channel memory controllers. The increasing density of these heterogeneous computing systems has resulted in complex performance phenomena including nonuniform memory access (NUMA) and resource contention that make application performance hard to predict and tune. This paper presents the Topology Aware Resource Usability and …

Temperature Effects On The Swelling And Bentonite Extrusion Characteristics Of Gcls, James L. Hanson, Nazli Yesiller, Everett P. Allen

Civil and Environmental Engineering

This investigation was conducted to evaluate effects of temperature on swelling and bentonite extrusion properties of GCLs. The swelling characteristics were determined using standardized test procedures and extrusion characteristics were determined using a new test method developed by the authors. Tests were conducted on a conventional medium-weight woven/nonwoven GCL. The range of test temperatures was 2 to 98°C (swelling tests) and -5 to 100°C (extrusion tests). The extrusion tests were conducted under stresses between 100 and 400 kPa and moisture contents between 50 and 150%. Temperature had significant effects on both swell and extrusion. The swell index ranged from 21 …

Advances Of Cone Penetration Testing In Earthquake Engineering Applications, Robb E.S. Moss, R. Moffat

Civil and Environmental Engineering

The Cone Penetration Test (CPT), because of its precision, accuracy, and utility has been increasingly used in earthquake engineering applications in the last decade. This paper provides a brief survey of recent advances in applying the CPT to; liquefaction triggering, post-liquefaction deformations, cyclic failure of clays, dynamic slope stability, and seismic site response. In granular soils the continuous CPT measurements of tip and sleeve resistance are well correlated with the engineering properties of relative density and friction angle. In clay soils the CPT tip resistance is directly proportional to the undrained shear strength. CPT measurements are ideal for weak or …

Teaching Consolidation: Case Study Of Preloading With Vertical Drains, Robb Moss, Judd King, Gregg Fiegel

Civil and Environmental Engineering

This paper describes a ground improvement case study where preloading and prefabricated vertical drains (PVDs) were used to accelerate foundation settlements. The case study is used in a classroom setting with the learning objective of introducing engineering students to methods for estimating settlement of shallow foundations on compressible soils. The project site was developed for a corporate retail chain planning to open a new facility in San Luis Obispo, California. Up to 2.5 meters of fill were needed across much of the site to raise foundations and improvements above the flood elevation. Loads from the fill and the structure were …

Site Response Analysis Considering Strain Compatible Site Period, Hoss Hayati, Robb E.S. Moss

Civil and Environmental Engineering

In practice it is common to estimate site effects using a single proxy, or single variable such as 30 m shear wave velocity (V_S30) or site period. Many studies have investigated merits of proposed proxies with contradicting recommendations. Yet, most studies indicate the single proxy approach is less than ideal, resulting in large uncertainty. To provide a better understanding of components that drive site response, we performed a parameterized study on 19 shallow soil profiles with V_S ranging from 150 m/s to 400 m/s. We propagated 74 input motions through each soil column using one-dimensional equivalent-linear …

Site Response Analysis Considering Strain Compatible Site Period, Hoss Hayati, Robb E.S. Moss

Civil and Environmental Engineering

In practice it is common to estimate site effects using a single proxy, or single variable such as 30 m shear wave velocity (V_S30) or site period. Many studies have investigated merits of proposed proxies with contradicting recommendations. Yet, most studies indicate the single proxy approach is less than ideal, resulting in large uncertainty. To provide a better understanding of components that drive site response, we performed a parameterized study on 19 shallow soil profiles with V_S ranging from 150 m/s to 400 m/s. We propagated 74 input motions through each soil column using one-dimensional equivalent-linear …

Nonparametric Liquefaction Triggering And Postliquefaction Deformations, J. S. Yazdi, Robb Moss

Civil and Environmental Engineering

This study evaluates granular liquefaction triggering case-history data using a nonparametric approach. This approach assumes no functional form in the relationship between liquefied and nonliquefied cases as measured using cone penetration test (CPT) data. From a statistical perspective, this allows for an estimate of the threshold of liquefaction triggering unbiased by prior functional forms, and also provides a platform for testing existing published methods for accuracy and precision. The resulting threshold exhibits some unique trends, which are then interpreted based on postliquefaction deformation behavior. The range of postliquefaction deformations are differentiated into three zones: (1) large deformations associated with metastable …

Heat Management Strategies For Msw Landfills, Nazli Yesiller, James L. Hanson, Kevin B. Kopp, Emma H. Yee

Civil and Environmental Engineering

Heat is a primary byproduct of landfilling of municipal solid waste. Long-term elevated temperatures have been reported for MSW landfills under different operational conditions and climatic regions around the world. A conceptual framework is presented for management of the heat generated in MSW landfills. Three main strategies are outlined: extraction, regulation, and supplementation. Heat extraction allows for beneficial use of the excess landfill heat as an alternative energy source. Two approaches are provided for the extraction strategy: extracting all of the excess heat above baseline equilibrium conditions in a landfill and extracting only a part of the excess heat above …

Geotechnical Effects Of The 2015 Magnitude 7.8 Gorkha, Nepal, Earthquake And Aftershocks, Robb E.S. Moss, Eric M. Thompson, D. Scott Kieffer, Binod Tiwari, Youssef M.A. Hashash, Indra Acharya, Basanta Raj Adhikari, Domniki Asimaki, Kevin B. Clahan, Brian D. Collins, Sachindra Dahal, Randall W. Jibson, Diwakar Khadka, Amy Macdonald, Chris L.M. Madugo, H. Benjamin Mason, Menzer Pehlivan, Deepak Rayamajhi, Sital Uprety

Civil and Environmental Engineering

This article summarizes the geotechnical effects of the 25 April 2015 M 7.8 Gorkha, Nepal, earthquake and aftershocks, as documented by a reconnaissance team that undertook a broad engineering and scientific assessment of the damage and collected perishable data for future analysis. Brief descriptions are provided of ground shaking, surface fault rupture, landsliding, soil failure, and infrastructure performance. The goal of this reconnaissance effort, led by Geotechnical Extreme Events Reconnaissance, is to learn from earthquakes and mitigate hazards in future earthquakes.

Evaluation Of In-Ground Plastic-Hinge Length And Depth For Piles In Marine Oil Terminals, Rakesh K. Goel

Civil and Environmental Engineering

This investigation evaluated the current recommendations for plastic-hinge length and depth for piles in marine oil terminals considering nonlinear pile and soil behavior, as well as two seismic design levels: Level 1 and Level 2. It was found that the plastic-hinge length depends on seismic design level, whereas depth is independent of seismic design level. For pre-stressed concrete piles, the current plastic-hinge length recommendations were generally found to be adequate for seismic design Level 2, but provided much smaller plastic-hinge length for Level 1. For hollow-steel piles, the current plastic-hinge length recommendation was generally found to be adequate for sands, …

Implications Of Variable Waste Placement Conditions For Msw Landfills, Jason T. Cox, Nazli Yesiller, James L. Hanson

Civil and Environmental Engineering

This investigation was conducted to evaluate the influence of waste placement practices on the engineering response of municipal solid waste (MSW) landfills. Waste placement conditions were varied by moisture addition to the wastes at the time of disposal. Tests were conducted at a California landfill in test plots (residential component of incoming wastes) and full-scale active face (all incoming wastes including residential, commercial, and self-delivered components). The short-term effects of moisture addition were assessed by investigating compaction characteristics and moisture distribution and the long-term effects by estimating settlement characteristics of the variably placed wastes. In addition, effects on engineering properties …

Geotechnical Field Reconnaissance: Gorkha (Nepal) Earthquake Of April 25, 2015 And Related Shaking Sequence, Youssef M.A. Hashash, Binod Tiwari, Robb E.S. Moss, Domniki Asimaki, Kevin B. Clahan, D. Scott Kieffer, Doug S. Dreger, Amy Macdonald, Chris M. Madugo, H. Benjamin Mason, Menzer Pehlivan, Deepak Rayamajhi, Indra Acharya, Basanta Adhikari

Civil and Environmental Engineering

The April 25, 2015 Gorkha (Nepal) Earthquake and its related aftershocks had a devastating impact on Nepal. The earthquake sequence resulted in nearly 9,000 deaths, tens of thousands of injuries, and has left hundreds of thousands of inhabitants homeless. With economic losses estimated at several billion US dollars, the financial impact to Nepal is severe and the rebuilding phase will likely span many years. The Geotechnical Extreme Events Reconnaissance (GEER) Association assembled a reconnaissance team under the leadership of D. Scott Kieffer, Binod Tiwari and Youssef M.A. Hashash to evaluate geotechnical impacts of the April 25, 2015 Gorkha Earthquake and …

Waste Heat Generation: A Comprehensive Review, Nazli Yeşiller, James L. Hanson, Emma H. Yee

Civil and Environmental Engineering

A comprehensive review of heat generation in various types of wastes and of the thermal regime of waste containment facilities is provided in this paper. Municipal solid waste (MSW), MSW incineration ash, and mining wastes were included in the analysis. Spatial and temporal variations of waste temperatures, thermal gradients, thermal properties of wastes, average temperature differentials, and heat generation values are provided. Heat generation was influenced by climatic conditions, mean annual earth temperatures, waste temperatures at the time of placement, cover conditions, and inherent heat generation potential of the specific wastes. Time to onset of heat generation varied between months …

Liquefaction Potential Of Recent Fills Versus Natural Sands Located In High-Seismicity Regions Using Shear-Wave Velocity, R. Dobry, T. Abdoun, K.H. Stokoe Ii., R. E.S. Moss, M. Hatton, H. El Ganainy

Civil and Environmental Engineering

The liquefaction potential of clean and silty sands is examined on the basis of the field measurement of the shear-wave velocity, Vs. The starting point is the database of 225 case histories supporting the Andrus-Stokoe Vs-based liquefaction chart for sands, silts, and gravels. Only clean and silty sands with nonplastic fines are considered, resulting in a reduced database of 110 case histories, which are plotted separately by type of deposit. A line of constant cyclic shear strain, γcl≈0.03%, is recommended for liquefaction evaluation of recent uncompacted clean and silty sand fills and earthquake magnitude, Mw=7.5. The geologically recent natural silty …

Routing Strategies For Emergency Management Decision Support Systems During Evacuation, Joseph Yu, Anurag Pande, N. Nezamuddin, Vinayak Dixit, Frances Edwards

Civil and Environmental Engineering

Simulation studies of urban transportation networks have been increasingly applied to evacuation planning. The level of detail provided within a traffic simulation model allows for devising strategies for evacuation and emergency response. In this research, simulation model of downtown San Jose, California, transportation network is developed to evaluate the efficiency of the evacuation process under hypothetical scenarios. Although the scenarios evaluated herein are not exhaustive, they demonstrate the potential of the simulation approach for managing traffic engineering aspects of the emergency response. The scenarios described here include the use of contraflow lanes, traffic incidents on the network, and a modal …

Determination Of Specific Gravity Of Municipal Solid Waste, Nazli Yesiller, James Hanson, Jason Taylor Cox, Danielle E. Noce

Civil and Environmental Engineering

This investigation was conducted to evaluate experimental determination of specific gravity (G_s) of municipal solid waste (MSW). Water pycnometry, typically used for testing soils was adapted for testing MSW using a large flask with 2000 mL capacity and specimens with 100–350 g masses. Tests were conducted on manufactured waste samples prepared using US waste constituent components; fresh wastes obtained prior and subsequent to compaction at an MSW landfill; and wastes obtained from various depths at the same landfill. Factors that influence specific gravity were investigated including waste particle size, compaction, and combined decomposition and stress history. The …

Analyst B: Analysis Of The Utexas1 Passive Linear Surface Wave Dataset, Robb E.S. Moss

Civil and Environmental Engineering

A linear array consisting of 24 1 Hz geophones at 10 m spacing was used to measure the passive surface waves at the UTexas1 site. This paper describes analysis of this dataset using three different methods: ESPAC (extended spatial autocorrelation), f-k (frequency-wavenumber), and ReMi (refraction microtremor). Dispersion curves were developed using each method and the median trends as well as the uncertainty about the medians are compared. The dispersion curves were then individually inverted to estimate shear wave velocity profiles. The inversion results are compared, and a bounded best-estimate shear wave velocity profile is presented. For the site conditions, specific …

Bayesian Approach For Uncertainty Analysis Of An Urban Storm Water Model And Its Applications To A Heavily Urbanized Watershed, Misgana K. Muleta, Jonathan Mcmillan, Geremew G. Amenu, Steven J. Burian

Civil and Environmental Engineering

The significance of uncertainty analysis (UA) to quantify reliability of model simulations is being recognized. Consequently, literature on parameter and predictive uncertainty assessment of water resources models has been rising. Applications dealing with urban drainage systems are, however, very limited. This study applies formal Bayesian approach for uncertainty analysis of a widely used storm water management model and illustrates the methodology using a highly urbanized watershed in the Los Angeles Basin, California. A flexible likelihood function that accommodates heteroscedasticity, non-normality, and temporal correlation of model residuals has been used for the study along with a Markov-chain Monte Carlo-based sampling scheme. …

Development Of Numerical Model For Predicting Heat Generation And Temperatures In Msw Landfills, James L. Hanson, Nazli Yesiller, Michael T. Onnen, Wei-Lien Liu, Nicolas K. Oettle, Janelle A. Marinos

Civil and Environmental Engineering

A numerical modeling approach has been developed for predicting temperatures in municipal solid waste landfills. Model formulation and details of boundary conditions are described. Model performance was evaluated using field data from a landfill in Michigan, USA. The numerical approach was based on finite element analysis incorporating transient conductive heat transfer. Heat generation functions representing decomposition of wastes were empirically developed and incorporated to the formulation. Thermal properties of materials were determined using experimental testing, field observations, and data reported in literature. The boundary conditions consisted of seasonal temperature cycles at the ground surface and constant temperatures at the far-field …

Veryifying Liquefaction Remediation Beneath And Earth Dam Using Spt And Cpt Based Methods, Ikram Guettaya, Mohamed Ridha El Ouni, Robb Moss

Civil and Environmental Engineering

This paper presents a case study of liquefaction potential assessment for the foundation of an earth dam in Tunisia. An emphasis was made on the exploration of geotechnical conditions and the interpretation of field tests (SPT and CPT) and the results were collected before and after soil densification using the vibrocompaction technique. The assessment of soil liquefaction triggering was made using deterministic and probabilistic simplified procedures. The results indicate that before vibrocompaction the studied area was prone to the liquefaction hazard. However, after vibrocompaction a significant improvement of the soil resistance reduced the liquefaction potential of the sandy foundation soil. …

Transferability And Robustness Of Real-Time Freeway Crash Risk Assessment, Cameron Shew, Anurag Pande, Cornelius Nuworsoo

Civil and Environmental Engineering

This study examines the data from single loop detectors on northbound (NB) US-101 in San Jose, California to estimate real-time crash risk assessment models. Method: The classification tree and neural network based crash risk assessment models developed with data from NB US-101 are applied to data from the same freeway, as well as to the data from nearby segments of the SB US-101, NB I-880, and SB I-880 corridors. The performance of crash risk assessment models on these nearby segments is the focus of this research. Results: The model applications show that it is in fact possible to use the …

Shear-Wave Velocity–Based Probabilistic And Deterministic Assessment Of Seismic Soil Liquefaction Potential, R. Kayen, R. E.S. Moss, E.M. Thompson, R. B. Seed, K. O. Cetin, A. Der Kiureghian, Y. Tanaka, K. Tokimatsu

Civil and Environmental Engineering

Shear-wave velocity (Vs) offers a means to determine the seismic resistance of soil to liquefaction by a fundamental soil property. This paper presents the results of an 11-year international project to gather new Vssite data and develop probabilistic correlations for seismic soil liquefaction occurrence. Toward that objective, shear-wave velocity test sites were identified, and measurements made for 301 new liquefaction field case histories in China, Japan, Taiwan, Greece, and the United States over a decade. The majority of these new case histories reoccupy those previously investigated by penetration testing. These new data are combined with previously published case histories to …