Kiewit Engineering Co.

Omaha, NE, United States

Kiewit Engineering Co.

Omaha, NE, United States
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Wehbe N.,South Dakota State University | Konrad M.,Kiewit Engineering Company | Breyfogle A.,00 East Broadway
Transportation Research Record | Year: 2016

Precast, prestressed double tee bridge girders are widely used for accelerated bridge construction on local roads in South Dakota. A common issue among double tee bridges in South Dakota is the rapid deterioration of longitudinal joints (shear keyways) between adjacent girders. Deteriorated joints allow moisture and deicing chemicals to reach the deck reinforcement, which leads to premature corrosion of reinforcing steel and spalling of concrete. The structural performance of conventional and proposed longitudinal joints between precast double tee bridge girders was examined experimentally under cyclic and monotonic loading. The proposed continuous joint with overlapping steel mesh reinforcement in a grouted shear keyway exhibited serviceability and strength performance characteristics substantially improved over those of the conventional grouted joint with discrete welded connections. © 2016, National Research Council. All rights reserved.

Saye S.R.,Kiewit Engineering Co | Brown D.A.,Dan Brown and Associates LLC | Lutenegger A.J.,University of Massachusetts Amherst
Journal of Geotechnical and Geoenvironmental Engineering | Year: 2013

This paper presents a method to estimate the side resistance of a driven displacement-pipe pile in clay using the stress history and normalized soil engineering parameter (SHANSEP) concept. The side resistance is treated as an adhesion, and this adhesion is normalized to the effective overburden stress. This normalized adhesion is then related to the soil overconsolidation ratio using an adaptation of the SHANSEP concept to separate the normally consolidated behavior from the overconsolidated behavior. This approach provides a rational means of screening representative measurements of undrained shear strength from measurements that may have been affected by sample disturbance. Assessments of the soil overconsolidation ratio are developed with laboratory odometer test data and an empirical approach using laboratory undrained strength data. A database of pile load tests screened for the effects of incomplete set-up and soil-property data screened for the effects of sample disturbance is used to evaluate the normalized side resistance and the relationship of normalized side resistance to overconsolidation ratio. © 2013 American Society of Civil Engineers.

Harris D.K.,Michigan Technological University | Lutch R.H.,Kiewit Engineering Co. | Ahlborn T.M.,Michigan Technological University | Duong P.,L.B. Foster CXT Inc.
Journal of Transportation Engineering | Year: 2011

In response to rising energy costs, there is increased demand for efficient and sustainable transportation of people and goods. One source of such transportation is the railroad. To accommodate the increased demand, railroads are constructing new track and upgrading existing track. This update to the track system will increase its capacity and make it a more reliable means of transportation compared to other alternatives. In addition to increasing the track system capacity, railroads are considering an increase in the size of the typical freight rail car to allow larger tonnage. An increase in rail car loads will, in turn, require the design of track components to accommodate these loads. This design change is especially pertinent to crossties that support the rail and serve to transmit loads down to the substructure. Today, the use of concrete ties is on the rise in North America as they become an economical alternative, competitive with the historical wood ties used in industry, providing performance that surpasses its competition in terms of durability and capacity. Because of the increased loads heavy-haul railroads are considering applying to their tracks, current designs of prestressed concrete railroad ties for heavy-haul applications may be undersized. In an effort to maximize tie capacity while maintaining tie geometry, fastening systems, and installation equipment, a parametric study to optimize the existing designs was completed. The optimization focused on maximizing the capacity of an existing tie geometry through an investigation of prestressing quantity, configuration, stress levels, and other material properties. The results of the parametric optimization indicate that the capacity of an existing tie can be increased most efficiently by increasing the diameter of the prestressing and concrete strength. Findings of the study demonstrate that additional research is needed to evaluate the true capacity of concrete ties because of the impacts of deep beam effects and inadequate development length in the rail seat region. © 2011 American Society of Civil Engineers.

Wehbe N.,South Dakota State University | Bahmani P.,Colorado State University | Wehbe A.,Kiewit Engineering Co.
International Journal of Concrete Structures and Materials | Year: 2013

The use of light-gauge steel framing in low-rise commercial and industrial building construction has experienced a significant increase in recent years. In such construction, the wall framing is an assembly of cold-formed steel (CFS) studs held between top and bottom CFS tracks. Current construction methods utilize heavy hot-rolled steel sections, such as steel angles or hollow structural section tubes, to transfer the load from the end seats of the floor joist and/or from the load-bearing wall studs of the stories above to the supporting load-bearing wall below. The use of hot rolled steel elements results in significant increase in construction cost and time. Such heavy steel elements would be unnecessary if the concrete slab thickening on top of the CFS wall can be made to act compositely with the CFS track. Composite action can be achieved by attaching stand-off screws to the track and encapsulating the screw shank in the deck concrete. A series of experimental studies were performed on full-scale test specimens representing concrete/CFS flexural elements under gravity loads. The studies were designed to investigate the structural performance of concrete/CFS simple beams and concrete/CFS continuous headers. The results indicate that concrete/CFS composite flexural elements are feasible and their structural behavior can be modeled with reasonable accuracy. © 2013 The Author(s).

Saye S.R.,Kiewit Engineering Co | Lutenegger A.J.,University of Massachusetts Amherst | Santos J.,Kiewit Engineering Co | Kumm B.P.,HDR
Journal of Geotechnical and Geoenvironmental Engineering | Year: 2013

Toenhance the assessment of the overconsolidation ratio (OCR), this paper describes the importance of relating the soil type and soil index properties to the empirical correlations used to evaluate the preconsolidation stress and OCR using the piezocone and the importance to apply the normalized soil behavior approach. Data from a variety of sites is assembled using published and unpublished sources to develop empirical correlations for the normalized soil behavior or the stress history and normalized soil engineering parameter-based approach that vary with the plasticity index, liquid limit, median particle size, and organic content of the soil. Examples are presented to illustrate application of the correlations. © 2013 American Society of Civil Engineers.

Wehbe N.,South Dakota State University | Wehbe A.,Kiewit Engineering Co. | Dayton L.,Nucor R and D | Sigl A.,South Dakota State University
Structures Congress 2011 - Proceedings of the 2011 Structures Congress | Year: 2011

Light-gauge steel (LGS) construction is widely used for commercial and industrial buildings. In such construction the wall framing is usually an assembly of cold-formed steel (CFS) studs held between CFS tracks while the floors are normally composite concrete/LGS decks on steel bar joists spanning between load-bearing CFS walls. Heavy hot rolled steel angles or HSS tubes are welded to the top of the CFS load-bearing walls to function as load distribution members (LDM) over the wall studs and as headers over wall openings. The use of hot rolled steel elements results in significant increase in construction cost and time. Such heavy steel elements would be unnecessary if the concrete thickening on top of the CFS wall can be made to act compositely with the CFS track. The resulting concrete/CFS composite beam would be a reinforced concrete beam where the CFS track serves as the tension reinforcement. The continuity at the interface would be provided by stand-off screws that are normally used in the construction of the composite deck. This research involved experimental and analytical studies to assess the structural performance and failure modes of concrete/CFS track composite beams and to develop optimum beam configurations for use in LGS construction. The parameters included the CFS track thickness, stand-off screw spacing, and stand-off screw configuration. Twenty-seven full-scale specimens were constructed, instrumented, and tested to failure. The flexural and shear strengths, flexural stiffness, and interface shear transfer were investigated. However, only the flexural strength and stiffness are reported in this paper. The results show that concrete/CFS track composite beams can be designed for ductile flexural failure and that the degree of composite action is dependent upon the stand-off screws intensity rather than configuration. Equations for the effective moment of inertia at service loads were derived. © ASCE 2011.

Walberg F.,URS Corporation | Saye S.,Kiewit Engineering Co. | Bird G.R.,URS Corporation | Linnan B.,URS Corporation | Boeckmann A.,University of Missouri
Geotechnical Special Publication | Year: 2013

Eppley Airfield in Omaha, Nebraska is sited along the west bank of the Missouri River with existing infrastructure and assets valued at a historical cost of more than $470 million and with an estimated annual economic impact of $750 million. Flood protection is provided by a federal levee system with sponsorship by the City of Omaha. The 2011 Missouri River Flood threatened the airfield, so the Omaha Airport Authority (OAA) assembled a team of engineers and contractors to fight the flood. Actions implemented by the project team included modification of pump stations, construction of outlet structures, berms, and graded filters, rehabilitation/pumping of existing relief wells, and installation/pumping of 70 new deep dewatering wells. The response actions were successful and the airfield operated continuously during the flood with no disruption in services or loss of critical facilities. The total cost of efforts to protect the airfield was about $24 million. Numerical seepage models were developed and calibrated during the flood to predict distress at higher river levels. © 2013 American Society of Civil Engineers.

Guthrie W.S.,Brigham Young University | Nolan C.D.,Kiewit Engineering Company | Bentz D.P.,U.S. National Institute of Standards and Technology
Transportation Research Record | Year: 2011

Scarification and overlay (SO) procedures are often performed on concrete bridge decks to minimize the corrosion of reinforcing steel caused by chloride ingress. The objectives of this research were to collect information from personnel of state departments of transportation (DOTs) about their SO procedures and to recommend the timing of initial SO procedures on concrete bridge decks to prevent the accumulation of corrosion-inducing levels of chlorides and to extend deck service life. A survey of state DOTs was conducted; numerical modeling of SO treatments was performed for decks both with and without stay-in-place metal forms (SIPMFs). Full-factorial numerical modeling was performed through a service life of 50 years to determine the recommended initial timing of SO treatment in each case. Research results showed that bridge decks without SIPMFs could endure longer delays in SO treatment timing than those with SIPMFs. The allowable delay in SO timing ranged from 2 years to 6 years for decks with SIPMFs, while the allowable delay ranged from 6 years to 18 years for decks without SIPMFs. In addition, results showed that the allowable delay also depended on the original cover depth (OCD). On average, for each additional 0.5 in. (12.7 mm) of OCD, the period of additional allowable delay for decks with SIPMFs was 2 years; for decks without SIPMFs, however, the additional allowable delay was 5 years with each additional 0.5 in. (12.7 mm) of OCD.

Zhang Y.,Iowa State University | Johnson A.E.,Kiewit Engineering Co. | White D.J.,Iowa State University
Cold Regions Science and Technology | Year: 2016

Freeze-thaw cycles in pavement foundation layers can cause rapid accumulation of pavement damage. To reduce the effects of freeze-thaw cycles, there is a need to characterize and design low frost susceptible foundation layers. This paper focuses on the laboratory frost-heave and thaw-weakening performance of pavement foundation materials that were stabilized with combinations of self-cementing class C fly ash, Portland cement, and polymer fibers. Additions of fly ash (15% by weight), cement, and cement + fibers presented improvement on frost susceptibility of soils. Grain size distribution and curing time and compaction delay of chemical stabilization influenced soil freeze-thaw performance. The heave rate has to be controlled to less than 4 mm/day to achieve very low thaw-weakening susceptibility per ASTM D5918. A proposed classification for chemically stabilized soils identifies thaw-susceptibility as negligible for post-test CBR values ≥ 100. © 2015 Elsevier B.V..

Fanous F.,Iowa State University | May J.,Kiewit Engineering Company | Wipf T.,Iowa State University
Journal of Bridge Engineering | Year: 2011

This paper presents simple relationships for calculating live-load distribution factors for glued-laminated timber girder bridges with glued-laminated timber deck panels. Analytical models were developed using the Ansys 11 finite-element program, and the results were validated using recorded data from four in-service timber bridges. The effects of the bridge span length, the spacing between girders, and the bridge width on the distribution of the live load were investigated by using the validated models. The live-load distribution factors obtained from the field test and the analytical models were compared with those obtained using the AASHTO LRFD Bridge Design Specifications live-load distribution relations. The comparison showed that the live-load distribution factors obtained by using the AASHTO LRFD Bridge Design Specifications were conservative. For this reason, statistical methods were used to develop accurate relationships that can be used to calculate the live-load distribution factors in the design of glued-laminated girder bridges. © 2011 American Society of Civil Engineers.

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