Bridging Historic Downtown Troutdale and The Confluence Site
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Date
2021-06
Authors
Kristof, Evan
Journal Title
Journal ISSN
Volume Title
Publisher
University of Oregon
Abstract
Troutdaleās Town Center District was established in the 19th century by pioneering families and is considered the cultural heart of their community.The Town Center District is 270 acres located south of Interstate I-84, and west of the Sandy River.The City of Troutdale has a robust Capital Improvement Plan with goals for the city's growth, supportable employment, civic-use spaces, and future economic development of the empty Confluence site behind the Columbia Gorge Outlets Shopping Center. Currently, there is no safe or direct route for pedestrian traffic from Historic Downtown Troutdale to the Confluence site as an active main-line Union Pacific Railway creates a barrier between these two areas. The purpose of this project is to connect the Downtown area to the newly developing Confluence site using a pedestrian bridge. This proposed design would be inclusive to pedestrians, cyclists, and neighborhood electric vehicles (golfcarts). The scope of this project is a 30% Initial design along with costing estimates for design, permitting, and construction that could take place in
the next five years.The foundation design was performed in accordance with geotechnical standards of practice using resources available from previous nearby geotechnical investigations, United States Geological Survey (USGS) data, as well data gathered on-site.In all cases, conservative design values a reused in calculations and design as described herein. At this time, any design recommendations should be considered preliminary, and further geotechnical exploration and data collection should be done to verify the design recommendations of this report. A shallow foundation analysis was performed. A range of allowable vertical loads was determined for a variety of footing geometries, and the most reasonable geometries were selected and recommended herein as potential footing geometries for the loads calculated in the preliminary analysis. Preliminary CAD drawings andtypical detail are provided for these shallowfoundation geometries in appendix C. In general, the loads determined require relatively large shallow footing supports. Due to the space limitations of the project, it is likely that deep foundations will be preferred as they will take less space and perhaps be less costly. Cursory deep foundation analysis has been performed using SHAFT software, and those calculations and preliminary design recommendations are provided in section 3.4.1 and appendix C and D.
For the structural design, the truss of the bridge is made out of W18x86 I-beams, except diagonal members that are made of W18x158. The horizontal perpendicular and diagonal members are made of W12x53 and W12x87 respectively since they are only for the lateral stiffness of the bridge. This means that they have a small axial loading where similar ones are used in the Lafayette street pedestrian bridge. The loading condition sand calculations followed the AASHTO LRFD 2012 Bridge Design Specifications 6th Ed (US) code, as shown in section 3.4.2 and the appendix.The columns of the bridge are constructed of a cast-in-place reinforced concrete with rectangular cross-section 3 ft x 6 ft, concrete compressive strength of 4000 psi, and grade 60 reinforcing steel.The longitudinal reinforcement is provided by 26-#9bar and the transverse reinforcement is provided by overlapping closed-loop #3 ties, following the American Association of State Highway and Transportation Officials (AASHTO) Bridge specifications. For the slab design, corrugated steel was used as a reinforcement with a two-inch concrete cover.U.S. BRIDGE provided the tests for the designed loading using different spans. Through two load combinations, the max moment of the floor beams was found and used to determine adequate members. A W10x17 section was selected and placed at a 4.33 feet spacing and at a 3-floor beam per panel.
Description
121 pages