Rehabilitation and Load Rating of Deteriorated Timber Bridges in Colorado: Parametric Investigations and Implementation

This report presents three major aspects that are related to the evaluation of timber bridges with and without repair: i) laboratory testing, ii) finite element modeling, and iii) load ratings. In addition, worked examples are provided to demonstrate the implementation of research findings. The first part of the report explores the effectiveness of various retrofit techniques in improving the flexural behavior of structural timber. The second part presents the behavior of a timber bridge strengthened with lag bolts, carbon fiber reinforced polymer (CFRP) sheets, and hollow structural sections (HSS). The third part discusses load ratings for timber bridges repaired with HSS. A mechanics-based rating approach is proposed to holistically rate these bridges before and after the repair. The capacity of the girders with the steel beams is as high as 2.56 times that of the control girders. Likewise, the allowable stress of the timber is improved by a factor of 1.39 and 2.09 for flexure and shear, respectively. The effectiveness of the repair becomes pronounced when the deterioration level of the timber girders rises, and the geometric properties of the steel beams are a crucial consideration that alters the rating of the repaired girders. The placement of grouped steel beams is recommended to raise the efficacy of the repair system

Development of Tub Girders for Prestressed Concrete Bridges Complying With LRFD

This report presents the development of tub girders for prestressed concrete bridges complying with the Load and Resistance Factor Design (LRFD) method. In addition, the use of 0.7 in. strands is elaborated for the B618-U girders of the Colorado Department of Transportation. In the first part of the report as regards a state-of-the-art review, technical parameters are categorized in accordance with physical characteristics and corresponding contents are examined. The second part of the report suggests a new tub girder series. After understanding the performance of tub girders selected from six transportation agencies in the nation, an optimization algorithm is employed to generate efficient prototype sections. Afterward, detailed investigations are conducted to appraise various practical aspects. A simplified version of the prototype sections is also delineated for regional precasters. A comparative study is carried out to evaluate the geometric stability and production costs of the prototype, simplified, and existing B618-U girders. Implementation: A new tub girder series is proposed to improve structural efficiency and the potential implementation of 0.7 in. strands is discussed for bridge construction in Colorado

Data-Driven Bridge Management Using Descriptive and Predictive Machine Learning Models

Bridges deteriorate with time and use. To monitor deterioration of the bridges, several US Acts mandate the state and local governmental agencies (including cities, state transportation agencies, etc.) to perform regular bridge inspections. The aforementioned inspections across the nation, which have been conducted since 1970\u2019s (including our region), have generated valuable historic databases of bridge data based in local and state governmental agencies. While these agencies currently use these inspections to prevent failure and to administrate the national bridge network by setting priorities and establishing criteria to allocate available resources to the structures in most critical conditions, we believe these databases are heavily underutilized. In particular, with the advent of machine learning and data mining methods, we envision data-driven solutions that can derive much more valued hidden knowledge that can be utilized for enhanced bridge management. While in the past, various data-driven deterioration models are proposed in the literature to model bridge deterioration, these models either suffer from low accuracy or are too complex to be applicable. Recently deep learning is shown to significantly outperform other analytical modeling methodologies in a variety of application domains. In this study, we present new deep learning models for enhanced bridge management. In particular, we focus on the two problems of bridge subtyping (descriptive analysis) and bridge deterioration forecasting (predictive analysis). Through empirical evaluation with real data, we demonstrate that our solutions for these problems significantly enhance the state-of-the-art in bridge management

AGENDA: Drawing the Blueprint for a Sustainable Natural Gas Future

A stakeholder-led forum discussing the key topics affecting natural gas as a safe and sustainable energy resource. Participants learned about the current research and related resources at Colorado’s three research universities and participated in designing future research needs

Pedagogy for Librarians

Most librarians are required to take classes on reference, collection development, and information organization in library school; courses on pedagogy, on the other hand, are usually optional, if they’re offered at all. This leads most librarians who end up with instruction duties to learn on the job. Activities and assessments can be learned on the fly fairly easily, but these often have little to no bearing on how much students actually absorb and recall weeks later because alone, they are usually insufficient to ensure deep learning. This chapter seeks to add the basics of pedagogy, a subject comprehensively covered in K-12 teacher preparation programs, to the librarian’s instructional repertoire

Irrationality in Metered Parking Payment Compliance [Final Report]

The existing parking system assumes that drivers can pay the right price for parking, but we find the opposite in a field study (N=567). Drivers either overpay or underpay for parking at on-street parking meters 98% of the time, for 20\u201330 minutes on average. Such misalignment between parking payments and presumed price can mask the price signal and reduce its power to influence drivers\u2019 behavior and downstream environmental consequences. These findings provide evidence for widespread parking payment inaccuracy and suggest a way forward for change. This research offers important insights for transportation and planning professionals on the future of parking

Where the Sidewalk Ends: Equity Disparities with Respect to Municipal Maintenance Policy [Project Title from Cover]

MPC 21-441The overarching goal of this research is to bridge the massive sidewalk data gap and begin to establish the next generation of data-driven sidewalk research and asset management efforts of cities. The underlying goal is to help improve deteriorating and disregarded pedestrian infrastructure as well as improve the mobility, health, safety, and access to opportunities for all that use or want to use sidewalks

AGENDA: Drawing the Blueprint for a Sustainable Natural Gas Future

A stakeholder-led forum discussing the key topics affecting natural gas as a safe and sustainable energy resource. Participants learned about the current research and related resources at Colorado’s three research universities and participated in designing future research needs

The Unresolved Relationship between Street Trees and Road Safety [Research Brief]

MPC-489Part 1 of this report relies upon advances in remote sensing to map both tree canopy and street-tree locations in GIS for the entirety of the city and county of Denver, Colorado. We then statistically test the association between street trees and seven years of road safety outcomes while controlling for factors known to be associated with crash outcomes. Part 2 investigates the usefulness of 3D volumetric pixels (voxels) and USGS Quality Level 2 (QL2) LiDAR data to measure features in streetscapes. As the USGS embarks on a national LiDAR database with the goal of covering the entire US with QL2 data or better, this paper investigates uses of QL2 LiDAR for the 3D measuring of streetscapes

Evaluating Sidewalk Infrastructure and Durability

USDOT 69A3551947137National Transportation Library (NTL) Curation Note: As this dataset is preserved in a repository outside U.S. DOT control, as allowed by the U.S. DOT\u2019s Public Access Plan (https://doi.org/10.21949/1503647) Section 7.4.2 Data, the NTL staff has performed NO additional curation actions on this dataset. The current level of dataset documentation is the responsibility of the dataset creator. NTL staff last accessed this dataset at its repository URL on 2023-08-16. If, in the future, you have trouble accessing this dataset at the host repository, please email [email protected] describing your problem. NTL staff will do its best to assist you at that time.This project leverages advances in technology and increasing access to high-resolution remote sensing and spatial data to develop methods for inventorying sidewalk characteristics and static obstructions across an entire major city. In part 1 of this effort, the authors analyze city-scale sidewalk availability, width, and land coverage calculated from spatial data from aerial imagery (planimetrics). The authors then determine how much of a difference accounting for static obstructions makes when measuring the clear width of sidewalks in one city. Part 2 then combines planimetric sidewalk data with vehicle and pedestrian trip big data to develop a methodology to prioritize city areas in need of pedestrian infrastructure attention. The results show an overall deficiency of sidewalks and indicate that deriving sidewalk availability, average width, and minimum clear width are feasible at the city scale. This zip file is approximately 80.71 MB. The following file types are standard for GIS mapping software: SHP, DBF, PRJ, CPG, SBN, SBX, and SHX. Because the files pertain to map layers and images, they are best viewed using the software that the team used or with any open source 2D and 3D mapping software. XML files are a markup language file that holds data. They can be opened using open-source programs such as Notepad or any text editor