Civil and Environmental Engineering Commons^™

Reply To Comment By Jonathan J. Rhodes On ‘‘Modeling Of The Interactions Between Forest Vegetation, Disturbances, And Sediment Yields’’, Charles H. Luce, David G. Tarboton, Erkan Istanbulluoglu, Robert T. Pack

Civil and Environmental Engineering Faculty Publications

Rhodes [2005] brings up some excellent points in his comments on the work of Istanbulluoglu et al. [2004]. We appreciate the opportunity to respond because it is likely that other readers will also wonder how they can apply the relatively simple analysis to important policy questions. Models necessarily reduce the complexity of the problem to make it tractable and synthesize some diverse sources of information. It may be helpful at times for readers to understand the high dimension of the complexity sacrificed in order to obtain the synthesis and the reasons for reducing the complexity in a particular manner. Rhodes …

Water Conservation And Resuse Strategy For Ireland, Liam Mccarton, Sean O'Hogain

Articles

The traditional approach to meeting increased demand is to augment supply. However, mobilising new resources involves ever higher costs. Increasing water efficiency by reducing the amount of water required to accomplish a given task can significantly contribute towards balancing supply and demand. The water saved as a result of PCC reduction can be used to augment existing supplies. This can be the least cost option, particularly when the environmental and social costs of developing new resources are included in the analysis. Allied to this is the concept of sustainability, which can be defined as ‘development that meets the needs of …

Ccfss Technical Bulletin Spring 2005, Wei-Wen Yu Center For Cold-Formed Steel Structures

CCFSS Technical Bulletins (1993 - 2020)

No abstract provided.

Retesting Of Liquefaction/Nonliquefaction Case Histories In The Imperial Valley, Robb E.S. Moss, Brian D. Collins, Daniel H. Whang

Civil and Environmental Engineering

This paper describes the retesting of liquefaction and nonliquefaction field case histories in the Imperial Valley using the electric cone penetration test (CPT). Subsurface testing of the River Park and Heber Road sites first occurred following the 1979 Imperial Valley earthquake (Bennett et al. 1981, Youd and Bennett 1983). These two sites are rich in information because they have experienced several earthquakes in recent history, have been subjected to moderate levels of strong ground shaking, the liquefiable layers have appreciable fines content, and the sites contain a number of high-quality non-liquefied data points. The recent liquefaction case history database for …

Extension Of Modal Pushover Analysis To Compute Member Forces, Rakesh K. Goel, Anil K. Chopra

Civil and Environmental Engineering

This paper extends the modal pushover analysis (MPA) procedure for estimating seismic deformation demands for buildings to compute member forces. Seismic demands are computed for six buildings, each analyzed for 20 ground motions. A comparison of seismic demands computed by the MPA and nonlinear response history analysis (RHA) demonstrates that the MPA procedure provides good estimates of the member forces. The bias (or error) in forces is generally less than that noted in earlier investigations of story drifts and is comparable to the error in the standard response spectrum analysis (RSA) for elastic buildings. The four FEMA-356 force distributions, on …

Response To B. Maison's Discussion Of "Evaluation Of Modal And Fema Pushover Analyses: Sac Buildings", Rakesh K. Goel, Anil K. Chopra

Civil and Environmental Engineering

No abstract provided.

Uncertainty In Projections Of Streamflow Changes Due To Climate Change In California, Edwin P. Maurer, Philip B. Duffy

Civil, Environmental and Sustainable Engineering

Understanding the uncertainty in the projected impacts of climate change on hydrology will help decision-makers interpret the confidence in different projected future hydrologic impacts. We focus on California, which is vulnerable to hydrologic impacts of climate change. We statistically bias correct and downscale temperature and precipitation projections from 10 GCMs participating in the Coupled Model Intercomparison Project. These GCM simulations include a control period (unchanging CO2 and other forcing) and perturbed period (1%/year CO2 increase). We force a hydrologic model with the downscaled GCM data to generate streamflow at strategic points. While the different GCMs predict significantly different regional climate …

Ccfss News Spring 2005, Wei-Wen Yu Center For Cold-Formed Steel Structures

CCFSS Newsletters (1999 - 2008)

No abstract provided.

Evaluation Of Alternate Cable Anchor Designs And Three-Cable Guardrail Adjacent To Steep Slope, Ryan M. Nelson, Dean L. Sicking, Ronald K. Faller, John D. Reid, John R. Rohde, Karla A. Polivka, Jason A. Hascall

Nebraska Department of Transportation: Research Reports

No abstract provided.

Development And Evaluation Of Lime Mortars For Restoration Of Historic Buildings And Monuments, Tarek Said Mahfouz

Archived Theses and Dissertations

Monuments and historic buildings and sites are regarded as a national treasure of any country. This is particularly true for Egypt that possesses a wealth of historic and heritage buildings covering the entire life span of human civilization. It must be preserved and safeguarded not only as historic evidences but also as works of art. Most of these structures used lime based mortars as binding material. These structures are deteriorating at a rate faster than our ability to renovate them. The repair and rehabilitation of old historic walls and mortars involve a complex interaction of existing and new elements. Engineers …

Bs News

Building Services Engineering

No abstract provided.

Behavior Of Structural Concrete Members Strengthened By Composite Fabrics, Jian Chen

Dissertations

The new technique of using Fiber Reinforced Polymer (FRP) materials to repair and strengthen various concrete members is becoming more and more popular in structural retrofitting field. Among all the confining materials, Carbon Fiber Reinforced Polymer (CFRP) fabric jackets are identified as an effective way to enhance the strength and ductility of concrete members due to its superior mechanical properties. This study investigates the detailed structural behavior of confined concrete members using CFRP fabric jackets by both analytical and experimental approaches.

A series of CFRP wrapped concrete cylinder tests were conducted to study the compressive stress-strain behavior for CFRP confined …

Corrosion Studies On Alpha Tantalum And Beta Tantalum Coated Steel, Sung Min Maeng

Dissertations

Tantalum coating by sputtering, one form of physical vapor deposition (PVD), has been investigated as a replacement for chromium coatings on gun bores to protect them from erosion and corrosion due to its high ductility and high corrosion resistance in aggressive environments. When deposited as a film on steel substrates by sputtering, either α-Ta, β-Ta, or a mixture of both phases have been observed under varying deposition conditions. To evaluate corrosion behavior of Ta coatings, electrochemical impedance spectroscopy and potentiodynamic polarization were conducted as a function of coating thickness. The coating porosity was observed to decrease with increasing coating thickness …

Bus Arrival Time Prediction Using Stochastic Time Series And Markov Chains, Rajat Rajbhandari

Dissertations

Public transit agencies rely on disseminating accurate and reliable information to transit users to achieve higher service quality and attract more users. With the development of new technologies, the concept of providing users with reliable information about bus arrival times at bus stops has become increasingly attractive. Due to the fact that bus operation parameters and variables are highly stochastic, modeling prediction of bus travel and arrival times has become one of the many challenging tasks.

Stochastic time series and delay propagation models to predict bus arrival times using historical information were developed. Markov models were developed to predict propagation …

Uniaxial And Triaxial Behavior Of High Strength Concrete With And Without Steel Fibers, Xiaobin Lu

Dissertations

This study first presents an extensive experimental research program on the true uniaxial and triaxial compression behavior for both high strength concrete (HSC) and steel fiber reinforced high strength concrete (SFHSC). The experimental study mainly focuses on the octahedral shear stress strain relationship of those two types of concrete, which is adopted as the basis to develop a new incremental constitutive model. Emphasis is also put on the investigation of the variation of tangent Poisson's ratio under not only uniaxial but also triaxial stress conditions. The effect of cyclic loading on this parameter is also addressed.

According to this research, …

Development And Application Of Fractionation Procedure For Drinking Water Organic Matters, Yong Pu

Dissertations

USEPA mandates a control of disinfection by-products (DBPs) in finished drinking water and recommends reduction of natural organic matters (NOM), DBP precursors, to achieve this regulatory goal. Studies relating NOM with DBP include fractionation of water samples, characterization of collected organic fractions, fractions' formation potential tests, and jar or similar tests to remove NOM. This study discussed a current resin fractionation procedure on principle, procedure, and its efficiency when applied to water samples of low NOM (< 5mgIL). The primary objective of this research is to develop a fractionation procedure intended for water of low NOM by carefully applying mass balance concept through each fraction's fractionation and a selection of stable ion exchange resins. A new protocol was presented with triple columns of XAD-8 adsorption resin, one column of AG-MP-50 cationic resin, and another column of WA 10 weak anionic resin in sequence. This protocol was experimented and confirmed for its efficiency (±10% loss of mass) with samples from Canal Road (CR) and Raritan Millstone (RM) surface water treatment plants (WTPs) in central New Jersey. The second objective of this study is to develop a statistical model with a potential of online delineation of organic fractions of NOM. The resulting model based on samples of Passaic Valley Water Commission (PVWC) WTP in northern New Jersey was applied to predict organic fractions of samples from CR and RM plants. Paired T-test (paired t ratio 1.15 < t critical 2.02) indicated a good correlation between the predicted and actual fraction concentration. Finally, samples of Middlesex Water Company (MWC) were fractionated and Trihalomethane formation potential tests (THMFP) on collected fraction showed hydrophilic matters possessed a higher potential to produce TTHM in finished water than hydrophobic matter. Jar tests indicated while coagulation was effective in removing hydrophobic matter, it may not be optimum for removal of hydrophilic matter.

This study developed an accurate fractionation procedure for low NOM waters. It provided a better understanding of organic matter transformation at different treatment …

Tide-Influenced Contaminant Transport In Coastal Aquifers, Yong Peng

Dissertations

Coastal aquifers are distinguished from other aquifers because of tidal effects which cause complicated groundwater flow and contaminant transport phenomena in regions immediately adjacent to the coast. This study is designed to address the significance of tidal influence on contaminant transport by focusing on one-dimensional homogeneous coastal aquifers.

This study formulates a conceptual model and corresponding flow and transport equations, analyzes coastal boundary conditions, solves numerically the transport equation, and uses experiments to verify the numerical results.

Results of numerical and experimental studies conclude that tides can have a significant impact on contaminant transport, especially when under unconfined conditions, subject …

Shear Stress In Smooth Rectangular Open-Channel Flows, Junke Guo, Pierre Y. Julien

Department of Civil and Environmental Engineering: Faculty Publications

The average bed and sidewall shear stresses in smooth rectangular open-channel flows are determined after solving the continuity and momentum equations. The analysis shows that the shear stresses are function of three components: (1) gravitational; (2) secondary flows; and (3) interfacial shear stress. An analytical solution in terms of series expansion is obtained for the case of constant eddy viscosity without secondary currents. In comparison with laboratory measurements, it slightly overestimates the average bed shear stress measurements but underestimates the average sidewall shear stress by 17% when the width–depth ratio becomes large. A second approximation is formulated after introducing two …

Optimization Of Shape, Size, And Topology Design Variables In Trusses With A Genetic Algorithm, Kevin M. Gillman

Theses and Dissertations

Briggs' genetic algorithm was extended in the Gillman algorithm to include shape optimization of trusses. Other contributions include value representation, different member linking, alternate genes, automatic k-factor evaluation for buckling, and the option to prevent overlapping members. The purpose of these contributions was to make optimization using a genetic algorithm more accessible to design engineers. The Gillman algorithm was demonstrated in two original examples as well as an example from a published work. The Gillman algorithm was effective in finding lighter designs.

Probabilistic Liquefaction Triggering Based On The Cone Penetration Test, Robb E.S. Moss, Raymond B. Seed, Robert E. Kayen, Jonathan P. Stewart, Kohji Tokimatsu

Civil and Environmental Engineering

Performance-based earthquake engineering requires a probabilistic treatment of potential failure modes in order to accurately quantify the overall stability of the system. This paper is a summary of the application portions of the probabilistic liquefaction triggering correlations proposed recently proposed by Moss and co-workers. To enable probabilistic treatment of liquefaction triggering, the variables comprising the seismic load and the liquefaction resistance were treated as inherently uncertain. Supporting data from an extensive Cone Penetration Test (CPT)-based liquefaction case history database were used to develop a probabilistic correlation. The methods used to measure the uncertainty of the load and resistance variables, how …

Thermal Analysis Of Gcls At A Municipal Solid Waste Landfill, James L. Hanson, Nazli Yesiller, G. E. Swarbrick

Civil and Environmental Engineering

This study was conducted to determine long-term thermal regime of landfill liner systems using a field temperature monitoring program and numerical analysis of heat transfer. Temperatures in liner systems that contain geosynthetic clay liners (GCLs) were monitored prior and subsequent to waste placement. Data were collected in three cells at a landfill in Midwestern USA for more than five years. The liner system in one of the cells was left exposed (not covered with waste) for a period exceeding one year subsequent to cell construction. The lowest and highest GCL temperatures were .1°C and 35°C, respectively and the localized temperature …

Computer-Simulation-Assisted Lean Manufacturing Training, Luoding Wang

Theses and Dissertations

This thesis assesses the potential of using computer simulation to aid existing lean manufacturing training methods such as lecture and live simulation. An investigation of this possibility was carried out in conjunction with UMEP's Lean 101 class. In the study, two experimental computer simulation models demonstrating the push and pull production scenarios were constructed using ProModel software. Simulation models were equipped with a Visual Basic interface to aid trainees to manipulate the model via ActiveX. Constructed computer simulation was compared with live simulation to answer these research questions: 1. Was computer simulation able to teach additional lean concepts not covered …

Performance Of Concrete Bridge Deck Joints, Lik Hang Yuen

Theses and Dissertations

The purpose of this research was to identify the types of joints available for use on concrete bridge decks and to investigate the performance characteristics of each type, including primary functions and movement ranges. Eleven reports on joint performance published by state departments of transportation and universities nationwide were analyzed in order to obtain information on joint performance problems typically encountered by state transportation agencies. In addition, test methods and specifications provided by the American Society for Testing and Materials (ASTM) were reviewed for application by bridge engineers to ensure the adequacy of deck joints.

The research indicates that compression …

Sub-Surface Corrosion Research On Rock Bolt System, Perforated Ss Sheets And Steel Sets For The Yucca Mountain Repository — Quarterly Technical Report No. 2, Dhanesh Chandra

Publications (YM)

This report encompasses the work done for second quarter in accordance to cooperative agreement of UCCSN for the Task 019 “Subsurface Corrosion Research on Rock Bolt System, Perforated SS Sheets and Steel Sets for the Yucca Mountain Repository”, the objective of which was proposed earlier, to conduct corrosion research and predict the durability of rock-bolts and other underground metallic roof supports. We have recently started working on oxidation tests using Thermogravimetric Analyzer, stress corrosion cracking/hydrogen embrittlement studies on rock bolts, other support materials including bench mark materials. In this quarterly report we will discuss “Dry” oxidation of steels and other …

Supplement 2004 To The North American Specification For The Design Of Cold-Formed Steel Structural Members 2001 Edition, American Iron And Steel Institute

American Iron and Steel Institute (AISI) Specifications, Standards, Manuals and Research Reports (1946 - present)

The material contained herein has been developed by a joint effort of the American Iron and Steel Institute Committee on Specifications, the Canadian Standards Association Technical Committee on Cold Formed Steel Structural Members (S136), and Camara Nacional de la Industria del Hierro y del Acero (CANACERO) in Mexico. The organizations and the Committees have made a diligent effort to present accurate, reliable, and useful information on cold-formed steel design. The Committees acknowledge and are grateful for the contributions of the numerous researchers, engineers, and others who have contributed to the body of knowledge on the subject. Specific references are included …

Supplement 2004 To The North American Specification For The Design Of Cold-Formed Steel Structural Members, American Iron And Steel Institute

American Iron and Steel Institute (AISI) Specifications, Standards, Manuals and Research Reports (1946 - present)

The material contained herein has been developed by a joint effort of the American Iron and Steel Institute Committee on Specifications, the Canadian Standards Association Technical Committee on Cold Formed Steel Structural Members (S136), and Camara Nacional de la Industria del Hierro y del Acero (CANACERO) in Mexico. The organizations and the Committees have made a diligent effort to present accurate, reliable, and useful information on cold-formed steel design. The Committees acknowledge and are grateful for the contributions of the numerous researchers, engineers, and others who have contributed to the body of knowledge on the subject. Specific references are included …

Distortional Buckling Of Cold-Formed Steel Members In Bending, Cheng Yu, Benjamin W. Schafer

American Iron and Steel Institute (AISI) Specifications, Standards, Manuals and Research Reports (1946 - present)

Laterally braced cold-formed steel beams generally fail due to local and/or distortional buckling in combination with yielding. For many cold-formed steel (CFS) studs, joists, purlins, or girts, distortional buckling may be the predominant buckling mode. However, distortional buckling of CFS beams remains a largely unaddressed problem in the current North American Specification for the Design of Cold-Formed Steel Structural Members (NAS). Further, adequate experimental data on unrestricted distortional buckling in bending is unavailable. Therefore, two series of bending tests on industry standard CFS C and Z-sections were performed and presented in this dissertation. The testing setup was carefully designed in …

Quantifying Savings From Improved Boiler Operation, Kevin Carpenter, J. Kelly Kissock

Mechanical and Aerospace Engineering Faculty Publications

On/off operation and excess combustion air reduce boiler energy efficiency. This paper presents methods to quantify energy savings from switching to modulation control mode and reducing excess air in natural gas fired boilers.

The methods include calculation of combustion temperature, calculation of the relationship between internal convection coefficient and gas flow rate, and calculation of overall heat transfer assuming a parallel-flow heat exchanger model. The method for estimating savings from changing from on/off to modulation control accounts for purge and drift losses through the boiler and the improved heat transfer within the boiler due to the reduced combustion gas flow …

Thermal Analysis Of Gcls At A Municipal Solid Waste Landfill, J. L. Hanson, Nazli Yesiller, G. E. Swarbrick

Civil and Environmental Engineering

This study was conducted to determine long-term thermal regime of landfill liner systems using a field temperature monitoring program and numerical analysis of heat transfer. Temperatures in liner systems that contain geosynthetic clay liners (GCLs) were monitored prior and subsequent to waste placement. Data were collected in three cells at a landfill in Midwestern USA for more than five years. The liner system in one of the cells was left exposed (not covered with waste) for a period exceeding one year subsequent to cell construction. The lowest and highest GCL temperatures were –1°C and 35°C, respectively and the localized temperature …

The Influence Of Ammonia And Carbon Dioxide On The Sorption Of A Basic Organic Pollutant To A Mineral Surface, Maneerat Ongwandee, Glenn Morrison, S. S. Bettinger

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Indoor surfaces have a sorptive capacity for organic pollutants which may be significantly influenced by other gases and the pH of the surface. in this research, we examine the influence of a common indoor gaseous acid, CO₂, and base, NH₃, on the adsorption of a volatile organic base, trimethylamine (TMA), to a mineral surface, zirconium silicate beads. Varying ammonia and CO₂ within concentration ranges of indoor relevance substantially influences the sorptive capacity of this mineral surface. Increasing the CO₂ mixing ratio to 1000 p.p.m. enhances surface capacity of TMA by 40-50%; increasing the NH3 …