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Full-Text Articles in Engineering
Nonlinear Lateral Pile Deflection Prediction In Sands, Shamsher Prakash, Sanjeev Kumar
Nonlinear Lateral Pile Deflection Prediction In Sands, Shamsher Prakash, Sanjeev Kumar
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
A method has been developed to predict the load-displacement relationship for single piles subjected to lateral load, embedded in sands, considering soil nonlinearity using subgrade reaction. This is the first systematic study to develop lateral load-deflection curves using modulus degradation with strain. Based on the analysis of 14 full-scale lateral pile-load tests, an empirical equation of modulus degradation with strain and a range of k hmax values, i.e., k h at 0.002 strain at 1 m (3.28 ft) depth, has also been proposed. An example problem is included to demonstrate its use. Based on this method, the computed load deflections …
Degradation Of Trichloroethylene By Methanol-Grown Cultures Of Methylosinus Trichosporium Ob3b Pp358, Mark W. Fitch, G. E. Speitel, G. Georgiou
Degradation Of Trichloroethylene By Methanol-Grown Cultures Of Methylosinus Trichosporium Ob3b Pp358, Mark W. Fitch, G. E. Speitel, G. Georgiou
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
A Soluble Methane Monooxygenase-Constitutive Mutant Strain of Methylosinus Trichosporium OB3b, Strain PP358, Was Grown with Methanol as the Carbon Source, and the Kinetics of Trichloroethylene (TCE) Degradation Were Determined. PP358 Exhibited High TCE Degradation Rates under Both Oxygen- and Carbon-Limiting Conditions. the Optimal Pseudo First-Order Rate Constant for TCE Was Comparable to the Values Measured for Cells Grown with Methane. We Found that Growth under Oxygen-Limiting Conditions Results in Increased Accumulation of Polyhydroxybutyrate, Which in Turn Correlates with Higher Transformation Capacities for TCE. It Was Also Shown that Methanol Inhibits TCE Degradation Only at High Concentrations. Thus, Methanol-Grown Cultures of …
Bending And Shear Behavior Of Web Elements With Openings, M. Y. Shan, Roger A. Laboube, Wei-Wen Yu
Bending And Shear Behavior Of Web Elements With Openings, M. Y. Shan, Roger A. Laboube, Wei-Wen Yu
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
Cold-formed steel C-sections are frequently used as wall studs and floor joists in both commercial and residential construction. To facilitate installation of ancillary systems such as electrical wiring and plumbing, the C-section is manufactured with a web opening. Although the opening offers construction advantages, it may degrade the structural integrity of the member. To quantify the degrading effect of a web opening, a study has been conducted at the University of Missouri-Rolla (UMR). The UMR study included the loading conditions of bending, shear, web crippling, and the combinations thereof. This paper summarizes the results of an experimental study which addressed …
Comparison Of Linear And Nonlinear Seismic Drift Histories For Midrise Steel Frames, K. Z. Truman, C. Pantelides, Richard A. Behr, Abdeldjelil Belarbi
Comparison Of Linear And Nonlinear Seismic Drift Histories For Midrise Steel Frames, K. Z. Truman, C. Pantelides, Richard A. Behr, Abdeldjelil Belarbi
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
The linear and nonlinear seismic responses for two midrise office buildings of five- and 24-storeys were generated by two independent research groups using three commercial analysis packages, ABAQUS, SAP90 and DRAIN-2DX. The results indicate that a variability of up to 25% occurred between the independent research groups' seismic responses. Originally, these models and analyses were generated for the purpose of aiding in the development of load histories for the seismic testing of architectural glass at the University of Missouri-Rolla. The independent researchers were provided with the same structures, accelerograms and basic modelling assumptions and were directed to perform both linear …
Computer Simulations Versus Real Experiments In A Portable Structural Mechanics Laboratory, Richard A. Behr
Computer Simulations Versus Real Experiments In A Portable Structural Mechanics Laboratory, Richard A. Behr
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
Efforts are being made to develop practical and effective innovations for undergraduate engineering teaching laboratories. The 'ANEX' process, in which computer simulations are compared in nearly real time with physical measurements made on bench-scale model experiments, is now being used successfully in an introductory structural analysis course. ANEX is described, as well as current plans to develop software simulation modules and matched, bench-scale model experiments for new 'MECH-ANEX' laboratory applications in lower-division statics and mechanics of materials courses. The ANEX process could also be adapted to undergraduate laboratory applications in a wider range of engineering and science disciplines.
On Seismic Displacements Of Rigid Retaining Walls, Yingwei Wu, Shamsher Prakash
On Seismic Displacements Of Rigid Retaining Walls, Yingwei Wu, Shamsher Prakash
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
Rigid retaining walls experience both sliding and rocking displacement during earthquakes. Richards and Elms' (1979) method incorporates only sliding displacements in design. A realistic method of computing both sliding and rocking displacements of the walls based on nonlinear soil properties both for the base soil and backfill was developed by Rafnsson and Prakash (1994). A design procedure based on this method was then developed by Prakash. et al (1995, b). Comparisons of the displacements of typical walls by both the methods have been made. Also, typical field data from recent earthquakes has been analyzed to compare the observed displacements with …
Development Of A Loading History For Seismic Testing Of Architectural Glass In A Shop-Front Wall System, C. P. Pantelides, K. Z. Truman, Richard A. Behr, Abdeldjelil Belarbi
Development Of A Loading History For Seismic Testing Of Architectural Glass In A Shop-Front Wall System, C. P. Pantelides, K. Z. Truman, Richard A. Behr, Abdeldjelil Belarbi
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
Moderate earthquakes can pose significant threats to the serviceability and structural integrity of the architectural glazing systems that are included in most building envelope systems. Building envelope damage can cause considerable economic losses due to operational disruptions for extended periods following an earthquake. Furthermore, glazing system structural failures are potentially hazardous to both building occupants and pedestrians. In this paper a systematic analytical study of the effect of the SOOE component of the 1940 El Centro earthquake on the response of a one-storey glass and aluminum shop-front wall system is presented. The seismic response of a one-storey commercial building comprised …
Performance Of Laminated Glass Units Under Simulated Windborne Debris Impacts, Richard A. Behr, Paul A. Kremer
Performance Of Laminated Glass Units Under Simulated Windborne Debris Impacts, Richard A. Behr, Paul A. Kremer
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
Severe windstorm events such as Hurricane Andrew in 1992 have underscored the vulnerability of building envelopes to breaching under the combined effects of windborne debris impacts and wind pressures. Damage to building interiors and disruption of building functions are exacerbated greatly when building envelopes are breached. When the inner glass ply in a laminated glass window unit is unbroken, the integrity of that part of the building envelope is preserved - provided that the inner glass ply has sufficient resistance to subsequent positive and negative wind pressures. In an effort to develop glazing systems that are resistant to breaching due …
Behavior Of Low Ductility Steels In Cold-Formed Steel Connections, S. Seleim, Roger A. Laboube
Behavior Of Low Ductility Steels In Cold-Formed Steel Connections, S. Seleim, Roger A. Laboube
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
Accepted design approaches for the strength of a steel connection rely on adequate ductility of the connected parts. In cold-formed steel connection design, adequate ductility is defined by the Specification for the Design of Cold-Formed Steel Members. To assess the influence of low ductility steels, i.e. steels not meeting the specification ductility requirements, single lap bolted connections were studied. The experimental study reflected key connection strength parameters: edge distance, sheet thickness, sheet width, bolt pattern, Fu/Fy, and percentage elongation. Test results indicate that failure modes in low ductility steels are inconsistent with observed failure modes in adequate ductility steels. It …
Multiobjective Optimization Of Structures With And Without Control, Franklin Y. Cheng, Dan Li
Multiobjective Optimization Of Structures With And Without Control, Franklin Y. Cheng, Dan Li
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
A multiobjective optimization algorithm is introduced, and the effect of different objective functions on structural design is investigated. The basic idea of this approach is to support the decisionmaker by directly selecting the best compromise solution from the Pareto optimal solutions. A payoff matrix is first constructed by optimizing each objective function subject to the given constraints; a substitute function is then formed. Under the original constraint conditions, maximizing the substitute function gives the best compromise solution. This research shows that multiobjective optimization should be carried out to obtain a rational structural design. Two structural optimal design examples - one …
Effects Of Accelerated Weathering On Architectural Laminated Glass In A Windstorm Environment, Richard A. Behr, Joseph E. Minor, Paul A. Kremer
Effects Of Accelerated Weathering On Architectural Laminated Glass In A Windstorm Environment, Richard A. Behr, Joseph E. Minor, Paul A. Kremer
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
An experimental study was conducted to assess the serviceability and ultimate limit state behavior of a fully glazed architectural laminated glass system under accelerated weathering conditions. Glazed specimens included heat-strengthened laminated glass with a low-emissivity, metallic solar coating on one glass surface next to the polyvinyl butyral interlayer. The laminated glass units were anchored to the aluminum curtain wall frame with a perimeter anchor bead of medium-modulus structural silicone sealant. Accelerated weathering was performed in a manner similar to the provisions of ASTM E773-88 and E774-92. All specimens (weathered and unweathered) were then subjected to a severe windstorm simulation test, …
Seismic Test Methods For Architectural Glazing Systems, Richard A. Behr, Abdeldjelil Belarbi
Seismic Test Methods For Architectural Glazing Systems, Richard A. Behr, Abdeldjelil Belarbi
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
An ongoing effort is being made at the University of Missouri-Rolla to develop standard laboratory test methods and codified design procedures for architectural glass under seismic loadings. Recent laboratory work has yielded some promising results regarding the development of an appropriate seismic test method for architectural glass, as well as identifying ultimate limit states that quantify the seismic performance and damage thresholds of various glass types. Specifically, a straightforward "crescendo-like" in-plane dynamic racking test, performed at a constant frequency, has been employed successfully. Two ultimate limit states for architectural glass have been defined: (1) a lower ultimate limit state corresponding …
Phytoremediation: Plant Uptake Of Atrazine And Role Of Root Exudates, Joel G. (Gerard) Burken, Jerald L. Schnoor
Phytoremediation: Plant Uptake Of Atrazine And Role Of Root Exudates, Joel G. (Gerard) Burken, Jerald L. Schnoor
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
Phytoremediation is an Emerging Technology for Degradation of Organic Chemicals. the Potential of Phytoremediation in the Cleanup of Contaminated Sites and Prevention of Non-Point-Source Pollution Was Examined with the Pesticide Atrazine in Two Experimental Systems. Uptake Was Determined in Batch Experiments with 14C Ring-Labeled Atrazine and Hybrid Poplar Trees Grown in Two Soil Types. Mineralization Was Studied Utilizing Soil Microcosms with the Addition of Root Exudates. Results Indicate that Poplar Cuttings Were Able to Uptake the Majority of Applied Atrazine that Was Not Tightly Sorbed to the Organic Fraction of the Soil, with No Detectable Adverse Effects to the Trees. …