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- Robustness (4)
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- Damaged steel frames (2)
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- Column loss (1)
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- DEFORMATION (1)
- Damaged steelframes (1)
- Disproportionate collapse analysis (1)
- Disproportionate collapse analysis; (1)
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Articles 1 - 11 of 11
Full-Text Articles in Engineering
Estimation Of Suspended Sediment Concentration From Remote Sensing And In Situ Measurement Over Lake Tana, Ethiopia, Zelalem R. Womber, Fasikaw A. Zimale, Mebrahtom G. Kebedew, Bekalu W. Asers, Nikole M. Deluca, Christian D. Guzman, Seifu A. Tilahun, Benjamin F. Zaitchik
Estimation Of Suspended Sediment Concentration From Remote Sensing And In Situ Measurement Over Lake Tana, Ethiopia, Zelalem R. Womber, Fasikaw A. Zimale, Mebrahtom G. Kebedew, Bekalu W. Asers, Nikole M. Deluca, Christian D. Guzman, Seifu A. Tilahun, Benjamin F. Zaitchik
Civil and Environmental Engineering Faculty Publication Series
Discharge from basins joining a lake is the main factor determining the lake volume and sediment inflow to the lake. Suspended sediment is an important parameter for describing the water quality of aquatic ecosystems. Lake Tana is an important and the largest lake in Ethiopia for the local ecological system. However, environmental change and anthropogenic activities in the area threaten its water quality. The conventional methods of suspended sediment concentration (SSC) observation are unable to determine and compare spatial and temporal SSC patterns for the lake over a period of years. Remote sensing methods have made it possible to map …
In Vivo Evaluation Of Oxygenic Photogranules’ Photosynthetic Capacity By Pulse Amplitude Modulation And Phototrophic–Irradiance Curves, Joseph G. Gikonyo, Andrew Keyser, John Tobiason, Jeeyon Jeong, Chul Park
In Vivo Evaluation Of Oxygenic Photogranules’ Photosynthetic Capacity By Pulse Amplitude Modulation And Phototrophic–Irradiance Curves, Joseph G. Gikonyo, Andrew Keyser, John Tobiason, Jeeyon Jeong, Chul Park
Civil and Environmental Engineering Faculty Publication Series
The commingled microbial moiety of oxygenic photogranules (OPGs) facilitates aeration-free wastewater treatment. Embedded in an extracellular polymeric substances (EPS) matrix, microbial producers and consumers of oxygen occupying granular niches exchange substrates among themselves and with the bulk fluid. An assessment of the OPG's phototrophic potential or functional capacity may require combining different photoactivity signals. The photosynthetic capacity was evaluated using photosynthetic oxygen evolution (POE) and chlorophyll fluorescence (rapid light curves, RLC) measurements using OPGs grown at different light intensities.. A maximum oxygen generating capacity for optimal OPGs and reactor conditions was determined to be 284.4 mgO(2) gVSS(-1) h(-1) The OPGs …
On The Measurements Of Individual Particle Properties Via Compression And Crushing, Chunlong Liu, Fengyin Liu, Jinliang Song, Fuli Ma, Dongfang Wang, Guoping Zhang
On The Measurements Of Individual Particle Properties Via Compression And Crushing, Chunlong Liu, Fengyin Liu, Jinliang Song, Fuli Ma, Dongfang Wang, Guoping Zhang
Civil and Environmental Engineering Faculty Publication Series
An experimental study is presented to measure the elastic, yielding, and crushing properties of individual particles under compression using substrates made of aluminum alloy, stainless steel, and sapphire. Carefully selected, highly spherical individual Ottawa sand particles of 0.75-1.1 mm in nominal diameter were compressed between two smooth substrates, and the load-deformation curves were analyzed by Hertz elastic contact theory to derive their reduced modulus and Young's modulus as well as yielding and crushing strengths, which vary significantly with the type of substrate materials. Further analysis of the yielding and plastic deformation at the particle-substrate contact shows that the yield strength …
A Simple One-Scale Constitutive Model For Static Liquefaction Of Sand-Silt Mixtures, Yang Liu, Ching-Shung Chang, Shun-Chuan Wu
A Simple One-Scale Constitutive Model For Static Liquefaction Of Sand-Silt Mixtures, Yang Liu, Ching-Shung Chang, Shun-Chuan Wu
Civil and Environmental Engineering Faculty Publication Series
Instability of liquefaction is one of the major reasons which results in the failure of earth structure such as dam. The present study focuses on the simulation of static liquefaction behavior for granular materials such as sand and sand-silt mixtures. Based on micromechanical analysis of inter-particle behavior, a simple one-scale model is proposed to simulate the stress-strain response of sand; then the proposed model is extended to simulate the sand-silt mixtures using the mixture theory combining the properties of sand and silt according to their proportions. Empirical expressions are introduced to fit the critical state strength and the location of …
When Nanoparticles Meet Biofilms — Interactions Guiding The Environmental Fate And Accumulation Of Nanoparticles, Kaoru Ikuma, Alan W. Decho, Boris L.T. Lau
When Nanoparticles Meet Biofilms — Interactions Guiding The Environmental Fate And Accumulation Of Nanoparticles, Kaoru Ikuma, Alan W. Decho, Boris L.T. Lau
Civil and Environmental Engineering Faculty Publication Series
Bacteria are essential components of all natural and many engineered systems. The most active fractions of bacteria are now recognized to occur as biofilms, where cells are attached and surrounded by a secreted matrix of “sticky” extracellular polymeric substances. Recent investigations have established that significant accumulation of nanoparticles (NPs) occurs in aquatic biofilms. These studies point to the emerging roles of biofilms for influencing partitioning and possibly transformations of NPs in both natural and engineered systems. While attached biofilms are efficient “sponges” for NPs, efforts to elucidate the fundamental mechanisms guiding interactions between NPs and biofilms have just begun. …
Loss-Of-Stability Induced Progressive Collapse Modes In 3d Steel Moment Frames, Simos Gerasimidis, G. Deodatis, Thalia Kontoroupi
Loss-Of-Stability Induced Progressive Collapse Modes In 3d Steel Moment Frames, Simos Gerasimidis, G. Deodatis, Thalia Kontoroupi
Civil and Environmental Engineering Faculty Publication Series
This paper deals with the progressive collapse analysis of a tall steel frame following the removal of a corner column according to the alternate load path approach. Several analysis techniques are considered (eigenvalue, material nonlinearities, material and geometric nonlinearities), as well as 2D and 3D modelling of the structural system. It is determined that the collapse mechanism is a loss-of-stability-induced one that can be identified by combining a 3D structural model with an analysis involving both material and geometric nonlinearities. The progressive collapse analysis reveals that after the initial removal of a corner column, its two adjacent columns fail from …
A Computational Model For Full Or Partial Damage Of Single Or Multiple Adjacent Columns In Disproportionate Collapse Analysis Via Linear Programming, Simos Gerasimidis, C. Bisbos, C. Baniotopoulos
A Computational Model For Full Or Partial Damage Of Single Or Multiple Adjacent Columns In Disproportionate Collapse Analysis Via Linear Programming, Simos Gerasimidis, C. Bisbos, C. Baniotopoulos
Civil and Environmental Engineering Faculty Publication Series
The evaluation of the sensitivity or insensitivity of structures to local damage has been a major research field during the last decades, mainly provoked due to the series of aging structures and infrastructures. Many researchers have described this property as redundancy, others as the resistance to disproportionate collapse or robustness and still others as the ability of structural systems to display alternate load paths in case of a local damage. In any case, the problem for the evaluation of this property is increasingly alarming since many systems experience similar collapses (American Society of Civil Engineers (2009). Proceedings of Structures Congress …
A Mathematical Programming Computational Model For Disproportionate Collapse Analysis Of Steel Building Frames, Simos Gerasimidis, A. Ampatzis, C. Bisbos
A Mathematical Programming Computational Model For Disproportionate Collapse Analysis Of Steel Building Frames, Simos Gerasimidis, A. Ampatzis, C. Bisbos
Civil and Environmental Engineering Faculty Publication Series
Disproportionate collapse analysis aims to assure that frames, a commonstructural system of buildings, can survive unforeseen local events and a central modelingtool of such abnormal deterioration is the concept of column loss. This paperformulates an appropriate computational model on the basis of mathematical optimization,using the collapse load analysis problem of steel frames with pre-existingdamage. A respective collapse load robustness measure is proposed. The model hasthe ability to consider both full and partial column/node removals. It renders to be alinear programming model, if the US steel design regulations are used. A practicalexample is presented and several aspects are discussed.
Evaluation Of Wind Load Integration In Disproportionate Collapse Analysis Of Steel Moment Frames For Column Loss, Simos Gerasimidis, C. Baniotopoulos
Evaluation Of Wind Load Integration In Disproportionate Collapse Analysis Of Steel Moment Frames For Column Loss, Simos Gerasimidis, C. Baniotopoulos
Civil and Environmental Engineering Faculty Publication Series
The design of steel structures, in most cases, depends majorly on the level of wind loads which are prescribed by codes and regulations and are used in the structural analysis due to the fact that steel structures being light and ductile systems are strongly affected from a slight difference in the values of wind loading. During the last decades, disproportionate collapse analysis has become of major interest mainly due to the increasing number of failures occurring in that pattern. Commonly accepted guidelines and methods of analysis have been produced, the most dominating of which being the Department of Defense Facilities …
Steel Moment Frames Column Loss Analysis: The Influence Of Time Step Size, Simos Gerasimidis, C. Baniotopoulos
Steel Moment Frames Column Loss Analysis: The Influence Of Time Step Size, Simos Gerasimidis, C. Baniotopoulos
Civil and Environmental Engineering Faculty Publication Series
This paper applies two well-known structural dynamics computational algorithms to the problem ofdisproportionate collapse of steel moment frames applying the alternate load path method. Any problem of structural dynamics strongly depends on the accuracy and the reliability of the analysis method since the parameters involved in the selection of the appropriate algorithm are affected by the nature of the problem. Disproportionate collapse is herein simulated via a time history analysis used to ‘‘turn off’’ the effectiveness of an element to the structure. For this kind of problem the time step size of the computational algorithm is of major importance for …
Disproportionate Collapse Analysis Of Cable-Stayed Steel Roofs For Cable Loss, Simos Gerasimidis, C. Baniotopoulos
Disproportionate Collapse Analysis Of Cable-Stayed Steel Roofs For Cable Loss, Simos Gerasimidis, C. Baniotopoulos
Civil and Environmental Engineering Faculty Publication Series
Disproportionate collapse has been identified lately as a real cause of failure for structural engineering projects. Rare and unexpected, the phenomenon of disproportionate collapse usually results to many fatalities and thus, its analysis and mitigation is deemed necessary. This work describes the analysis of a cable-stayed steel roof under the scenario of a cable loss. The eventof a cable loss is assumed to be brittle, while relevant recent recommendations suggest the application of a scaled equivalent static force at the points of the anchorage of the cable but in the opposite direction of the original cable force. In this paper, …