David Evans and Associates Inc.

Portland, OR, United States

David Evans and Associates Inc.

Portland, OR, United States
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Higgins C.,Oregon State University | Amneus D.,Group Makenzie | Barker L.,David Evans and Associates Inc.
Sustainable Bridge Structures - 8th New York City Bridge Conference, 2015 | Year: 2015

A visually distressed vintage conventionally reinforced concrete deck girder (RCDG) bridge was identified by routine inspection. Subsequent investigation showed the distress was due to a poorly detailed splice location for the flexural steel and the ratings determined the girders to be significantly understrength. The bridge was shored to allow it to remain in service until it could be strengthened. The bridge was strengthened using near-surface mounted (NSM) titanium alloy bars. Round titanium alloy bars with a unique deformation pattern were specially developed for this application. Experimental research was conducted to evaluate the behavior of the as-built poorly detailed girder and then to evaluate the performance of the strengthening approach. Realistic full-scale girder specimens were constructed, instrumented, and tested to failure. The specimens mimicked the in situ materials, loading interactions, and geometry. The as-built strength was verified to be very low and the distress observed in the tests priot to failure and were similar to those observed in the field. Two specimens were strengthened with NSM titanium alloy bars and exhibited much higher strength and deformation capacity. The observed strengths of the specimens with NSM titanium enable the bridge to carry legal and permit loads without restriction. The member strength was shown to be well predicted using the analysis program Response 2000 and was conservatively predicted using AASHTO-LRFD design methods. The approach and materials were applied to the actual bridge, and the bridge was restored to service without the need for shoring or posting. The first ever application of titanium alloy bars to a reinforced concrete bridge was completed at a 30% cost savings compared to alternatives. © 2015 Taylor & Francis Group, London.

Barbosa A.R.,Oregon State University | Link T.,David Evans and Associates Inc. | Trejo D.,Oregon State University
Journal of Bridge Engineering | Year: 2016

This paper presents the results of a testing program developed to assess the performance of circular RC bridge columns constructed with ASTM A706 Grade 80 [550] high-strength steel (HSS) reinforcement. Two pairs of columns were tested (four columns in total). The columns were subjected to lateral cyclic loading to determine the effects of steel reinforcement grade (yield strength) and of moment-shear span ratio on column performance. Each pair consisted of one column constructed with Grade 80 [550] HSS reinforcement and a control column constructed with Grade 60 [420] reinforcement. The first pair had a moment-shear span ratio of six (6), and the second pair had a moment-shear span ratio of three (3). All four columns were designed to have similar nominal bending-moment capacities. Results indicate that the columns constructed with Grade 80 [550] HSS reinforcement achieve similar resistance, similar maximum lateral displacements, and similar curvature ductility values when compared with the control columns constructed with Grade 60 [420] reinforcement. However, columns constructed with Grade 80 [550] reinforcement exhibited lower hysteretic energy dissipation than the control columns. Results also indicate that, independently of the steel grade, as the moment-shear span ratio decreases, the maximum drift ratio decreases, despite an increase in the displacement ductility. © 2015 American Society of Civil Engineers.

Trejo D.,Oregon State University | Link T.B.,David Evans and Associates Inc. | Barbosa A.R.,Oregon State University
ACI Structural Journal | Year: 2016

Reinforcement grades higher than 75 ksi (520 MPa) are not allowed in members that form plastic hinges due to a lack of information on material characteristics and on the seismic performance of columns constructed with high-strength steel (HSS) reinforcement. This research investigated the performance of reinforced concrete columns containing Grade 80 (minimum yield strength of 80 ksi [550 MPa]) HSS reinforcement. Four columns were subjected to lateral cyclic loading to determine the effects of the steel reinforcement grade and longitudinal reinforcement ratio. Results indicate that columns constructed with Grade 80 (550) HSS reinforcement achieved similar resistances, similar maximum drifts, and similar curvature ductility values when compared with the control columns. Results also indicate that the effect of the longitudinal reinforcement ratio on column performance is similar for columns constructed with either Grade 60 or 80 (420 or 550) reinforcement. Columns constructed with Grade 80 (550) reinforcement exhibited lower energy dissipation than the control columns. Copyright © 2016, American Concrete Institute. All rights reserved.

Kim Y.J.,University of Colorado at Denver | Nickle R.W.,David Evans and Associates Inc.
ACI Structural Journal | Year: 2016

This paper addresses the calibration methodology of strength reduction factors for fiber-reinforced polymer (FRP) tendons used in prestressed concrete application. A total of 50 benchmark bridges are designed using aramid FRP (AFRP) and carbon FRP (CFRP) composites in accordance with the geometric and material properties of constructed bridges. Stochastic simulations are conducted to attain several subdesign factors necessary for calibrating the strength reduction factors of FRP-prestressed concrete bridge girders, based on the reliability requirements of the American Association of State Highway and Transportation Officials (AASHTO) Load and Resistance Factor Design (LRFD) Specifications. The proposed methodology is validated with published reliability responses, and further employed to determine resistance parameters and to identify a resistance distribution at the system level. The strength reduction factors of AFRP- and CFRP-prestressed girders are not significantly different from each other and, consequently, integrated reduction factors of 0.75 and 0.80 for tension-controlled and compression-controlled sections are suggested to update the reduction factors of ACI 440.4R-04. Copyright © 2016, American Concrete Institute. All rights reserved.

Byrne W.,David Evans and Associates Inc. | Upchurch J.,Grand Canyon National Park
ITE Journal (Institute of Transportation Engineers) | Year: 2011

Some of the significant improvements had resulted in improved visitor experiences and much less congestion at Grand Canyon National Park's South Rim. These results were expected to have implications for plans to address congestion and entrance station delays at other recreation areas. The general management plan envisioned that most of the travel needs for visitors to the South Rim was to be met by a significantly expanded transit system, including a shuttle system connecting the South Rim to a major parking facility to the south of the park boundary and an internal system of transit routes serving the major destinations in and near Grand Canyon Village. The primary components of the plan included added service lanes at the south entrance station and implementation of stacked fee collection stations to allow multiple vehicles to be served simultaneously in two of the lanes and Realignment of the main park access road away from the canyon rim to allow pedestrians to move between the newly developed areas.

Eidswick J.,Montana State University | Steinholtz P.,David Evans and Associates Inc.
Transportation Research Record | Year: 2011

Land managers can benefit from each other's successes and lessons learned through existing alternative transportation system (ATS) deployment efforts. For this reason, the Paul S. Sarbanes Transit in Parks Technical Assistance Center assembled a set of four case studies to document those successes and examine those lessons. The case studies focused on the partnerships that allowed the ATS to be implemented, integrated with other ATSs, and operated and, in some cases, to remain financially sustainable. The four partnership case studies were the Santa Ana National Wildlife Refuge, the North Moab Recreation Area, the Cape Cod National Seashore, and the Grand Island National Recreation Area. The objective of this study was to share the ATS model and partnership lessons learned from each of the four partnering endeavors. Although each of the four case studies had its own unique ATS and set of partners, the partnership lessons learned had some major common themes, including choosing partners carefully, clearly identifying partners' roles and responsibilities, meeting with partners on a regular basis, and making ongoing communication a priority. The ATS lessons learned also had some major common themes, including identifying support for the ATS both in the community and with national land management agency leaders and creating detailed financial plans and vehicle specifications.

Higgins C.,Oregon State University | Williams G.T.,Jacobs Engineering | Mitchell M.M.,David Evans and Associates Inc. | Dawson M.R.,Requardt and Associates LLP | Howell D.,Jacobs Engineering
ACI Structural Journal | Year: 2012

Fiber-reinforced polymers (FRPs) are increasingly being used to repair and strengthen conventionally reinforced concrete (RC) bridge members. Much of the existing performance data for members repaired with FRP have been developed from tests of reduced-scale specimens. This study reports experimental results for eight very large reinforced concrete deck girders (RCDGs) strengthened with surface-bonded carbon FRP (CFRP) for shear. The girders were designed to refect realistic mid-twentieth century vintage proportions, materials, and details. Test results show that the CFRP provided additional shear strength and deformation capacity, even with large debonded regions prior to failure. The materials also increased the member stiffness and failures were controlled by debonding of the U-wrapped CFRP strips along the edges of the deck-stem intersection. Copyright © 2012, American Concrete Institute. All rights reserved.

Salemann V.,David Evans and Associates Inc. | Soiseth S.,David Evans and Associates Inc.
Institute of Transportation Engineers Annual Meeting and Exhibit 2010 | Year: 2010

The choice of a design vehicle for a modern roundabout has significant influence on the safety, geometry, capacity, and cost of the roundabout. Large design vehicles must be accommodated appropriately, but not necessarily equally in all cases. Other design vehicles - large and small - must also be considered.

Bennett R.,David Evans and Associates Inc. | Adams M.,Port of Tacoma
Ports 2010: Building on the Past, Respecting the Future - Proceedings of the 12th Triannual International Conference | Year: 2010

In early 2008, the Port of Tacoma was in the process of redeveloping approximately 548 acres on the Blair Hylebos Peninsula in order to build two new marine terminals and the associated road, rail and infrastructure to support the terminals. Both terminals and the road, rail, and infrastructure elements were under design by three different design consultants. Upon receipt of the 30% Design cost estimates, the Port of Tacoma undertook a revalidation of the estimated costs for the entire program. The Port of Tacoma partnered with the Washington State Department of Transportation to undertake a Cost Estimate Validation Process (CEVP®) in combination with a Value Engineering Workshop in the summer of 2008 in order to refine the scope of the program, align costs between the design groups, and identify project delivery alternatives that could reduce either the cost or schedule delivery of the project. The undertaking included the review and validation of the estimated program cost ranges; identifying program wide risk issues for schedule and cost; and then probabilistic modeling (Monte Carlo simulation) to determine the probability for delivering the project on time and on budget. The risks identified during the process were to be managed during project development, to shift odds in favor of project success. The identification of scope reductions that could result in lower costs and/or earlier project delivery provided decision-makers with important information for deliberation and ultimate determination of the Port of Tacoma's future actions. © 2010 ASCE.

David Evans and Associates Inc. | Date: 2014-04-08

Lacrosse ball bags; Lacrosse balls; Lacrosse gloves; Lacrosse stick bags; Lacrosse stick handles; Lacrosse stick heads; Lacrosse stick strings; Lacrosse sticks.

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