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Full-Text Articles in Engineering
Seismic Response Study Of Asymmetric Systems With Linear And Nonlinear Fluid Viscous Dampers, Rakesh K. Goel
Seismic Response Study Of Asymmetric Systems With Linear And Nonlinear Fluid Viscous Dampers, Rakesh K. Goel
Civil and Environmental Engineering
This investigation is concerned with application of nonlinear fluid viscous dampers for asymmetric-plan systems. For this purpose, the behavior of nonlinear fluid viscous dampers is summarized first followed by the effects of damper nonlinearity on seismic response of asymmetric systems. It is shown that the peak force in nonlinear damper tends to be smaller compared to linear damper. However, this is true only for values of V / ůo less that a certain threshold value; for larger values of V / ůo, the force in nonlinear damper may become larger· than that in the linear damper. While …
Some Observed Queue Discharge Features At A Freeway Bottleneck Downstream Of A Merge, Robert L. Bertini, Michael J. Cassidy
Some Observed Queue Discharge Features At A Freeway Bottleneck Downstream Of A Merge, Robert L. Bertini, Michael J. Cassidy
Civil and Environmental Engineering
Details of traffic evolution were studied upstream and downstream of a freeway bottleneck located near a busy on-ramp. It is shown that on certain days the bottleneck became active upon dissipation of a queue emanating from somewhere further downstream. On such occasions, the bottleneck occurred at a fixed location, approximately one kilometer downstream of the merge. Notably, even after the dissipation of a downstream queue, the discharge flows in the active bottleneck were nearly constant, since the cumulative counts never deviated much from a linear trend. The average bottleneck discharge flows were also reproducible from day to day. The diagnostic …
Impact Of Soil Type And Compaction Conditions On Soil Water Characteristic, C. J. Miller, N. Yesiller, K. Yaldo, S. Merayyan
Impact Of Soil Type And Compaction Conditions On Soil Water Characteristic, C. J. Miller, N. Yesiller, K. Yaldo, S. Merayyan
Civil and Environmental Engineering
Tests were conducted to determine the variation of water content and pore water suction for compacted clayey soils. The soils had varying amounts of clay fraction with plasticities ranging from low to high plasticity. The unsaturated soil behavior was investigated for six conditions, covering a range of compactive efforts and water contents. The experimental data were fit to four commonly used models for the water content-pore water suction relationship. Each model provided a satisfactory fit to the experimental data. However, the individual parameters obtained from the curve fits varied significantly between models. The soil water characteristic curves (SWCCs) were more …
Dynamic Properties Of Fire Sprinkler Systems, James S. Dillingham, Rakesh K. Goel
Dynamic Properties Of Fire Sprinkler Systems, James S. Dillingham, Rakesh K. Goel
Civil and Environmental Engineering
Four fire protection systems have been attached to a small building model for testing their dynamic properties. Three of the systems used CPVC (fire rated) plastic pipes while the fourth was made from schedule-40 steel pipe. The building model was securely attached to a three by three foot shake table in one of two orientations and was able to experience base accelerations along both its principle axis (longitudinal, transverse). Test procedures involved sending a sine sweep with a progressively increasing frequency at a constant acceleration value. Various recording locations provided data showing fundamental frequencies with pronounced amplification over the base …
Influence Of Inclined Viscous Damper On Column Axial Force, Rakesh K. Goel
Influence Of Inclined Viscous Damper On Column Axial Force, Rakesh K. Goel
Civil and Environmental Engineering
This investigation examined the influence of inclined viscous damper on column axial force in a simple one-story frame building for harinonic loading and earthquake ground motion. It is shown that the peak column axial force in a system with inclined damper can be several times that in a system with horizontal damper, both having the same damping ratio. The amplification factor increases with increasing ratio of the forcing frequency to the system's natural frequency for harmonic loading, and with increasing system's natural vibration period for earthquake loading; the amplification also increases with increasing damping ratio. Furthermore, the peak column axial …
Evaluation Of Modal Pushover Analysis: Sac Buildings Excluding Gravity Loads, Anil K. Chopra, Rakesh K. Goel
Evaluation Of Modal Pushover Analysis: Sac Buildings Excluding Gravity Loads, Anil K. Chopra, Rakesh K. Goel
Civil and Environmental Engineering
No abstract provided.
Kinetics Of Mn(Ii) Oxidation By Leptothrix Discophora Ss1, Jinghao Zhang, Leonard W. Lion, Yarrow M. Nelson, Michael L. Shuler, William C. Ghiorse
Kinetics Of Mn(Ii) Oxidation By Leptothrix Discophora Ss1, Jinghao Zhang, Leonard W. Lion, Yarrow M. Nelson, Michael L. Shuler, William C. Ghiorse
Civil and Environmental Engineering
The kinetics of Mn(II) oxidation by the bacterium Leptothrix discophora SS1 was investigated in this research. Cells were grown in a minimal mineral salts medium in which chemical speciation was well defined. Mn(II) oxidation was observed in a bioreactor under controlled conditions with pH, O>sub>2, and temperature regulation. Mn(II) oxidation experiments were performed at cell concentrations between 24 mg/L and 35 mg/L, over a pH range from 6 to 8.5, between temperatures of 10°C and 40°C, over a dissolved oxygen range of 0 to 8.05 mg/L, and with L. discophora SS1 cells that were grown in the presence …
A Modal Pushover Analysis Procedure For Estimating Seismic Demands For Buildings, Anil K. Chopra, Rakesh K. Goel
A Modal Pushover Analysis Procedure For Estimating Seismic Demands For Buildings, Anil K. Chopra, Rakesh K. Goel
Civil and Environmental Engineering
Developed herein is an improved pushover analysis procedure based on structural dynamics theory, which retains the conceptual simplicity and computational attractiveness of current procedures with invariant force distribution. In this modal pushover analysis (MPA), the seismic demand due to individual terms in the modal expansion of the effective earthquake forces is determined by a pushover analysis using the inertia force distribution for each mode. Combining these ‘modal’ demands due to the first two or three terms of the expansion provides an estimate of the total seismic demand on inelastic systems. When applied to elastic systems, the MPA procedure is shown …
Evolutionary Algorithms For Multiobjective Evaluation Of Watershed Management Decisions, Misgana K. Muleta, John W. Nicklow
Evolutionary Algorithms For Multiobjective Evaluation Of Watershed Management Decisions, Misgana K. Muleta, John W. Nicklow
Civil and Environmental Engineering
The comprehensive and systematic management of watersheds is essential for reducing the adverse environmental impacts arising from anthropogenically caused erosion and subsequent sedimentation. This paper describes a computational methodology that is designed to serve as a watershed decision support system and is capable of controlling environmental impacts of non-point source pollution resulting from erosion. In the decision process, the methodology also accounts for other inseparable objectives such as economics and social dynamics of the watershed. This decision support tool was developed by integrating a comprehensive hydrologic model known as SWAT and state-of-the-art multiobjective optimization technique within the framework of a …