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Project Details
STATUS

Completed

START DATE

01/27/11

END DATE

07/31/15

FOCUS AREAS

Infrastructure

RESEARCH CENTERS InTrans, BEC, CTRE
SPONSORS

California Department of Transportation

Researchers
Principal Investigator
Sri Sritharan

Faculty Affiliate

About the research

A goal of the proposed work is to continue to improve the understanding of the true seismic behavior of a cap-to-girder connection that will facilitate ABC opportunities while mitigating the seismic hazard associated with bridge designs that utilize accelerated construction methods. To accomplish this purpose, we will design a prototype bridge and, using experimental and analysis methods, investigate the expected seismic performance of the girder-to-cap connection of the prototype.

Previous similar analytical work completed for the earlier inverted-tee project will be built upon to minimize the amount of analytical work associated with this investigation. The improved connection detail completed as part of the previous work will also be utilized again here to avoid unnecessary duplication of earlier work.

A large-scale bridge component test will be designed to replicate a portion of the prototype superstructure consisting of several precast I-girders and an inverted-tee pier cap using the girder-to-cap connection developed in the previous work. The model will be subjected to the seismic effects resulting from horizontal and vertical accelerations and fully quantify the elastic and plastic behavior of the connection. Using the test data, the accuracy of the analysis models will be evaluated.

The results of the experimental and analytical work will be used to create design guidelines, details, and examples that will enable increased use of accelerated bridge construction methods and increased understanding of how precast girder to cap connection should be detailed to address the concerns resulting from vertical ground acceleration. The research team will play a proactive role in disseminating project findings to Caltrans engineers and other interested designers and organizations and will also assist with rapidly deploying the research results into practice.

The inverted-tee test also revealed that use of untensioned, grouted tendons in the girder-to-cap might provide sufficient seismic resistance. The research team plans to develop individual component tests to compare the behavior of grouted tendons with different level of initial stresses and provide experimental behavior comparisons of the different options.

The research team is aware that in addition to the I-girder, Caltrans has utilized bulb-tee girders and perhaps even more commonly the California wide-flange (or super) girder. It is believed that experimental results established by using the I-girder configuration can also be applied to bulb-tee girders and the California Wide Flange Girder configuration. If needed, the experimental program could be altered to accommodate one of these girder types.

Project Details
STATUS

In-Progress

START DATE

10/01/10

END DATE

05/31/14

RESEARCH CENTERS InTrans, BEC, CTRE
SPONSORS

California Department of Transportation

Researchers
Principal Investigator
Sri Sritharan

Faculty Affiliate

About the research

The seismic performance of pier walls, hollow circular columns, and hollow rectangular columns confined with ties and cross-ties is crucial for the design of such systems. Large bridges with tall columns typically require hollow columns. There has been some limited testing of hollow columns, however, the analytical tools for design rely, to a great extent, on the models developed for solid columns. There is a need for improvement in the design and design analysis of hollow columns.
Project Details
STATUS

Completed

START DATE

10/01/09

END DATE

07/31/13

RESEARCH CENTERS InTrans, CTRE
SPONSORS

California Department of Transportation
Colorado Department of Transportation
Federal Highway Administration Transportation Pooled Fund
Illinois Department of Transportation
Indiana Department of Transportation
Iowa Department of Transportation
Minnesota Department of Transportation
Missouri Department of Transportation
Wisconsin Department of Transportation

Researchers
Principal Investigator
Chris Williams

Director, AMPP

Student Researcher(s)
Andrew Cascione
Jianhua Yu

About the research

State highway agencies are increasingly intersted in using recycled asphalt shingles (RAS) in hot mix asphalt (HMA) applications, yet many agencies share common questions about the effect of RAS on the performance of HMA. Previous research has allowed for only limited laboratory testing and field surveys. The complexity of RAS materials and lack of past experiences led to the creation of Transportation Pooled Fund (TPF) Program TPF-5(213). The primary goal of this study is to address research needs of state DOT and environmental officials to determine the best practices for the use of recycled asphalt shingles in hot-mix asphalt applications.Agencies participating in the study include Missouri (lead state), California, Colorado, Illinois, Indiana, Iowa, Minnesota, Wisconsin, and the Federal Highway Administration. The agencies conducted demonstration projects that focused on evaluating different aspects (factors) of RAS that include RAS grind size, RAS percentage, RAS source (post-consumer versus post-manufactured), RAS in combination with warm mix asphalt technology, RAS as a fiber replacement for stone matrix asphalt, and RAS in combination with ground tire rubber. Field mixes from each demonstration project were sampled for conducting the following tests: dynamic modulus, flow number, four-point beam fatigue, semi-circular bending, and binder extraction and recovery with subsequent binder characterization. Pavement condition surveys were then conducted for each project after completion.

The demonstration projects showed that pavements using RAS alone or in combination with other cost saving technologies (e.g., WMA, RAP, GTR, SMA) can be successfully produced and meet state agency quality assurance requirements. The RAS mixes have very promising prospects since laboratory test results indicate good rutting and fatigue cracking resistance with low temperature cracking resistance similar to the mixes without RAS. The pavement condition of the mixes in the field after two years corroborated the laboratory test results. No signs of rutting, wheel path fatigue cracking, or thermal cracking were exhibited in the pavements. However, transverse reflective cracking from the underlying jointed concrete pavement was measured in the Missouri, Colorado, Iowa, Indiana, and Minnesota projects.

Project Details
STATUS

Completed

START DATE

02/15/08

END DATE

09/30/11

FOCUS AREAS

Infrastructure

RESEARCH CENTERS InTrans, BEC, CTRE
SPONSORS

California Department of Transportation

Researchers
Principal Investigator
Sri Sritharan

Faculty Affiliate

Co-Principal Investigator
Shashi Nambisan

Transportation Research Engineer

About the research

The goal of this project was to understand the true seismic behavior of the cap-to-girder connection as currently used and to mitigate the potential seismic hazard associated with these bridges.

 

Project Details
STATUS

Completed

PROJECT NUMBER

MTC-2007-06

START DATE

03/01/07

END DATE

02/28/08

RESEARCH CENTERS InTrans, CTRE, MTC
SPONSORS

California Department of Transportation
Midwest Transportation Consortium
University of Missouri - Columbia

Researchers
Principal Investigator
Sam Kiger

University of Missouri - Columbia

About the research

  • Develop risk assessment procedures to identify critical bridges in a bridge network
  • Develop bridge vulnerability assessment guide
  • Develop concepts for mitigation and structural protection of bridges

Soon after the attacks of September 11, 2001, the Federal Highway Administration (FHWA) and the American Association of State Highway and Transportation Officials (AASHTO) assembled a Blue-Ribbon Panel of experts to develop strategies and provide guidance to improve the safety and security of bridge and tunnel infrastructure. This effort led to recognizing that the threat is real and can be devastating, risk assessment is necessary, and engineering guidance are needed based on research. Building on current and past efforts, the goal of this project is develop procedures to assist professionals and bridge owners identify critical bridges and to develop procedures to assess their vulnerability to explosions (terrorist’s bomb attacks). Potential Benefits of the Project The procedures and design guides developed in this project will benefit the bridge owners, designers, inspectors, and professionals nationwide.


Funding Sources:
California Department of Transportation
Midwest Transportation Consortium
University of Missouri – Columbia

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