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Kwon G.,Sargent and Lundy LLC | Engelhardt M.D.,University of Texas at Austin | Klingner R.E.,University of Texas at Austin
Journal of Bridge Engineering | Year: 2011

A number of older bridges were constructed with floor systems consisting of a noncomposite concrete slab over steel girders. A potentially economical means of strengthening these floor systems is to connect the existing concrete slab and steel girders with postinstalled shear connectors to permit the development of composite action. This paper presents the results of an experimental investigation of this concept. Five large-scale noncomposite beams were constructed, and four of these were retrofitted with postinstalled shear connectors and tested under static load. The retrofitted composite beams were designed as partially composite with a 30% shear connection ratio. A noncomposite beam was also tested as a baseline specimen. Test results showed that the strength and stiffness of existing noncomposite bridge girders can be increased significantly. Further, excellent ductility of the strengthened partially composite girders was achieved by placing the postinstalled shear connectors near zero-moment regions to reduce slip demand on the connectors. The test results also showed that current simplified design approaches commonly used for partially composite beams in buildings provide good predictions of the strength and stiffness of partially composite bridge girders strengthened using postinstalled shear connectors. © 2011 American Society of Civil Engineers.

Kwon G.,Sargent and Lundy LLC | Engelhardt M.D.,University of Texas at Austin | Klingner R.E.,University of Texas at Austin
Journal of Constructional Steel Research | Year: 2010

This paper describes a series of tests investigating methods to develop composite action in existing non-composite floor systems. Three types of 22-mm diameter post-installed shear connectors were tested under static and fatigue loading. Test results are compared with previous research results on 19-mm diameter, post-installed shear connectors as well as with conventional welded shear studs. Based on the test results, preliminary design equations are proposed for the static and fatigue strength of post-installed shear connectors. These post-installed shear connectors showed a significantly higher fatigue strength than conventional welded shear studs. The superior fatigue strength of these post-installed shear connectors enables the strengthening of existing bridge girders using significantly fewer shear connectors than possible with conventional welded shear studs. © 2009 Elsevier Ltd. All rights reserved.

Schroeder R.P.,Pennsylvania State University | Schroeder R.P.,Sargent and Lundy LLC | Thole K.A.,Pennsylvania State University
Proceedings of the ASME Turbo Expo | Year: 2016

Shaped holes are increasingly selected for airfoil cooling in gas turbines due to their superior performance over that of cylindrical holes, especially at high blowing ratios. The performance of shaped holes is regarded to be result of the diffused outlet which slows and laterally-spreads coolant, causing coolant to remain close to the wall. However, few thermal field measurements exist to verify this behavior at high blowing ratio or to evaluate how high freestream turbulence alters the coolant distribution in jets from shaped holes. The present study reports measured thermal fields, along with measured flowfields, for a shaped hole at blowing ratios up to 3 at both low and high freestream turbulence intensities of 0.5% and 13.2%. Thermal fields at low freestream turbulence intensity showed that the coolant jet was initially attached, but far downstream of the hole the jet lifted away from the surface due to the counter-rotating vortex pair. Elevated freestream turbulence intensity was found to cause strong dilution of the coolant jet and also increased dispersion, almost exclusively in the lateral as opposed to the vertical direction. Dominance of lateral dispersion was due to the influence of the wall on freestream eddies, as indicated from changes in turbulent shear stress between the low and high freestream turbulence cases. © Copyright 2016 by ASME.

Koopman A.A.,Ramgen Power Systems | Bahr D.A.,Sargent and Lundy LLC
Proceedings of the ASME Turbo Expo | Year: 2010

The objective of this paper is to better equip the reader with tools to make relative comparisons between different Carbon Capture and Sequestration (CCS) concepts including various CO2 compressor configurations with more confidence. Methods for analyzing comparative costs for CCS implementation in Coal plants, in terms of Levelized Cost of Electricity (LCOE) and cost per ton CO2 removed or avoided ($/tonCO2) are described. The contribution of compression to LCOE is significant and highly dependent on configuration. Critical inputs required for accurately calculating compressor power and some common errors that significantly impact the results of power consumption can increase the estimated power required by 40%. Sensitivity analyses for critical compressor characteristics are provided. In addition, the impact of energy (heat) integration on the overall economics of the plant can reduce the LCOE penalty. Finally, configuration parameters for systems meeting the national targets of 35% LCOE penalty for CCS costs are explored. Copyright © 2010 by ASME.

Bassam A.,Sargent and Lundy LLC | Ansari F.,University of Illinois at Chicago
Journal of Intelligent Material Systems and Structures | Year: 2016

This study describes development of an indirect method for reference-free monitoring of lateral displacements in concrete columns under dynamic loads. The method is independent of the material and section properties of the structure. Therefore, damage due to the change in material and section properties during seismic events does not affect the estimated displacement results. The approach involves discretization of the column elements and placement of strain sensors on opposing sides of the columns for the computation of curvature during the seismic events. Element equivalent force vectors are obtained from the measured strains and subsequently employed for the computation of lateral displacements. Fiber Bragg grating displacement sensors were employed for monitoring the strains. The experimental portion of the research involved shake table tests of a four-span bridge using the recorded ground motions of the 1994 Northridge earthquake. The objective was to verify the accuracy and efficiency of the proposed method by comparing the results with direct displacement measurements. Comparison of the proposed method with the direct measurement of the lateral displacements during the shake table tests indicated reasonable correlation between the computed and direct measurements. © The Author(s) 2014.

Marohl M.P.H.,Sargent and Lundy LLC
American Society of Mechanical Engineers, Pressure Vessels and Piping Division (Publication) PVP | Year: 2014

Calculation of pressures in a soil body due to finite loads imposed on the soil surface is a necessary step in the design and analysis of buried commodities. This study compares two commonly-applied numerical methods used to develop the vertical soil pressure profiles applied to buried pipes. The methods compared in this study differ in theory, basis, assumptions, complexity, and results, and therefore the comparison is meaningful. Provided is a comparison between design vertical forces on different sizes of buried pipes at a range of soil depth, determined using an integration of Boussinesq's equation [1] and the method specified by AASHTO [2]. The Boussinesq equation is defined as a function of location in varying two dimensional soil planes and the integration is performed over the boundary of the pipe as well as the applied soil surface footprint. The soil surface loading considered in this study includes the AASHTO Design Truck and the AASHTO Design Tandem, positioned as required by the AASHTO LRFD code [2]. Recommendations for application of the results is provided based upon the resulting force magnitude calculated and ease of application of the methods. Consideration of the effects of redistribution of loading due to pavements or other rigid surfaces is outside the scope of this study. Copyright © 2014 by ASME.

Devgun J.S.,Sargent and Lundy LLC
Proceedings of the International Conference on Radioactive Waste Management and Environmental Remediation, ICEM | Year: 2013

This paper examines the impact of three recent developments on the commercial nuclear power in the United States. These developments include: Yucca Mountain closure and issues related to SNF; actions in response to Fukushima Diaiichi accident, and; energy economics. All of these have had a significant impact on the commercial nuclear power, its future, as well as the reactor decommissioning scene in the US. Copyright © 2013 by ASME.

Hoang P.H.,Sargent and Lundy LLC
American Society of Mechanical Engineers, Pressure Vessels and Piping Division (Publication) PVP | Year: 2015

Solution for multi-axis loading on piping non-planar flaws has been studied by many authors (Hoang 2010, 2011), (Kunio 2012, 2014), (Li, 2010, 2012) and (Bezensek, 2010) to provide a technical basis for an equivalent moment in applications of ASME Section XI, Appendix C limit load approach for pipe flaw evaluation. The equivalent moment is defined as the square root of the sum of the squares (SRSS) of bending moment and torsion with a multiplier of Ce. It has been shown that Ce=1 is applicable for piping with crack-like planar flaws and for part-through-wall non-planar flaws subjected to some limitations. However, the Ce factor for through-wall non-planar flaws has not been investigated. Since Code Case 513-3 allows the use of Section XI, Appendix C procedure for non-planar through-wall flaws, the Ce factor is studied in this paper to support the applications with torsion loading. Copyright © 2015 by ASME.

Kelley B.P.,Sargent and Lundy LLC
Proceedings of the IEEE Power Engineering Society Transmission and Distribution Conference | Year: 2016

The electric utility industry has adjusted their thinking of substation physical security as a result of recent attacks and the issuance by NERC of CIP-014-1. As a result there is a substantial investment in upgrading existing station security and providing enhanced security at new stations. With this new design approach, there are a significant number of options, considerations and products to evaluate during the design of a physical security system. This paper will highlight key considerations that should be addressed during the design and implementation of a system to comply with CIP 014-1. © 2016 IEEE.

Cole J.M.,Sargent and Lundy LLC
Proceedings of the IEEE Power Engineering Society Transmission and Distribution Conference | Year: 2016

To minimize the vulnerability of the electric power grid to cyberattacks the North American Electric Reliability Corporation (NERC), under the jurisdiction of the Federal Energy Regulatory Commission (FERC), has enacted and enforced cybersecurity standards that continue to evolve as technology and the nature of these threats advance. These Critical Infrastructure Protection (CIP) standards issued by NERC require utilities to meet an aggressive timeline for regulatory compliance. To supplement in-house resources, utilities rely on consultants and suppliers to meet NERC's fast approaching deadlines, such as implementing the latest NERC CIP Version 5 (V5) standards. This paper discusses major design challenges faced when upgrading substation equipment for cybersecurity enhancements and, specifically, the hardware improvements implemented for the NERC CIP V5 conversions. © 2016 IEEE.

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