Metamorphic Geology of the Collinsville Area

Guidebook for field trips in Connecticut: New England Intercollegiate Geological Conference 60th annual meeting, Yale University, New Haven, Connecticut, October 25-27, 1968: Trip D-

Bedrock Geology of Western Connecticut

Guidebook for field trips in Connecticut: New England Intercollegiate Geological Conference 60th annual meeting, Yale University, New Haven, Connecticut, October 25-27, 1968: Trip D-

Analysis and Chronology of Structures Along the ChamplainThrust West of the Hinesburg Synclinorium

Guidebook for field trips in Vermont: 64th annual meeting October 13, 14, 15, 1972 Burlington, Vermont: Trip B-

A Transect Through the Foreland and Transitional Zone of Western Vermont

Guidebook for field trips in Vermont: New England Intercollegiate Geological Conference, 79th annual meeting, October 16, 17 and 18, 1987: Trips A-

Superposed Folds and Structural Chronology Along the Southeastern Part of the Hinesburg Synclinorium

Guidebook for field trips in Vermont: 64th annual meeting October 13, 14, 15, 1972 Burlington, Vermont: Trip B-

Fatigue Behavior of Welded Connections Enhanced with UIT and Bolting

A common problem in bridges employing welded steel girders is development of fatigue cracks at the ends of girder coverplates. Fatigue cracks tend to form at the toes of the transverse welds connecting a coverplate to a girder flange since this detail has a region of very high stress concentration. Because many aging bridges employ these fatigue-prone, AASHTO fatigue Category E or E' details, a means to effectively enhance the fatigue lives of these details is being sought. A research project funded by the Kansas Department of Transportation was undertaken at the University of Kansas to investigate the fatigue life enhancement afforded by two retrofit methods. One retrofit method was similar to a method described in the AASTHO Bridge Design Specification (AASHTO 2004) and involved pretensioned bolts being added to the ends of coverplates near the transverse welds. Unlike the AASHTO bolting procedure, the modified bolting procedure studied during this project utilized coverplates having transverse fillet welds that were left in the as-fabricated state. The other retrofit method was the use of a proprietary needle peening procedure called Ultrasonic Impact Treatment (UIT). Results of the research project showed that UIT was highly effective at enhancing the fatigue lives of coverplate end details while the bolting procedure was ineffective. Weld treatment with UIT resulted in an improvement in fatigue life over control specimens by a factor of 25. This translated in an improvement from an AASTHO fatigue Category E detail rating to and AASHTO fatigue Category A detail rating. The modified coverplate bolting procedure tested during this project had either no effect on fatigue life or, in some cases, had a detrimental effect on fatigue life. The coverplate bolting procedure included in the AASHTO specification allows a coverplate end detail to achieve a fatigue Category B resistance when bolted rather than transversely welded. 11 Therefore, the modified bolting procedure tested during this project was much less effective at enhancing fatigue life than either the AASHTO bolting procedure or UIT

Post Retrofit Analysis of the Tuttle Creek Bridge Br. No. 16-81-2.24

The Tuttle Creek Bridge was built in 1962. Like many older welded steel bridges, it has developed fatigue cracks. The majority of cracks were forming in the upper web-gap region. In addition, fatigue cracking was occurring along gusset plates in the structure. A retrofit was performed in 1986 to prevent further fatigue cracking. Unfortunately, the cracks propagated after the retrofit. Therefore, finite element models were created at the University of Kansas to investigate the continued fatigue cracking. The models supplied a more effective retrofit procedure that included attaching the connection stiffener to the upper flange of the girder. Two tests were planned to determine the effectiveness of the retrofit. The first field test occurred before the repair was started. Its purpose was to provide stress values in key areas for comparison after the repair. In addition, the pre-retrofit test provided information for future finite element models. In 2005, the second retrofit was completed. The purpose of this report is to present results of the post-retrofit test with data from the pre-retrofit test. Comparisons of stresses for each key area are included in the report. Details of the Tuttle Creek Bridge and testing procedure are provided. In addition, minor changes from the previous test are described

Field Instrumentation and Analysis of the Tuttle Creek Bridge

Fatigue cracking has been an extensive problem for many steel bridges designed prior to the identification of fatigue-prone details. Distortion in bridges coupled with stress concentrations within bridge components can eventually lead to crack initiation. The Tuttle Creek Bridge, built in 1962, has developed fatigue cracks like many older steel bridges. The structure is a 5,350 ft. long, plate-girder bridge with two girders supporting a non-composite concrete deck. The majority of the cracks on the bridge are found in the upper web-gap region, which lies between the vertical connection stiffener and the upper flange. Cracks also have occurred in the transverse welds attaching the lateral gusset plates to the lower flange. Both these crack types are believed to be caused by differential deflection of the two girders. In 1986, the bridge was retrofitted to prevent further cracking. Cracking, however, continued after the 1986 retrofit. In 2000, the Kansas Department of Transportation retained the services of the University of Kansas to investigate the fatigue cracking. Finite element models were created to estimate the stresses in the upper web-gap regions in order to determine a proper repair plan. The recommended repair scheme was to positively attach the connection stiffener to the upper flange, which was also successfully performed in similar web-gap repairs. The University of Kansas also was retained to perform two load tests on the bridge to investigate the effectiveness of the repair. The first load test, which this report entails, examined the stresses within the fatigued regions prior to retrofit. A second test will be conducted after the repairs have been performed. Measurements taken during both tests will be compared to determine the fatigue improvement within the structure. Also, information gathered during the first test will also provide insight to improving the finite element models. This report includes information about the Tuttle Creek Bridge and a summary of its structural deficiencies. Details of the gage installation and load testing are provided. Stresses induced by the truck loadings are presented in addition to the inferences from the measurements taken

A Transect Through the Pre-Silurian Rocks of Central Vermont; The Lincoln Massic and Its Immediate Cover; The Pre-Silurian Hinterland Along the Valleys of the White and Mad Rivers, Central Vermont; Metamorphism of Pre-Silurian Rocks, Central Vermont; Regional Geochemical Variations in Greenstones from the Central Vermont Appalachians

Guidebook for field trips in Vermont: New England Intercollegiate Geological Conference, 79th annual meeting, October 16, 17 and 18, 1987: Trips B-8; C-

Student Workbook - Fracture Mechanics for Bridge Design

P.O. No. 5-3-0209This workbook is a companion to the volume Fracture Mechanics for Bridge Design which provides an introduction to the elements of fracture mechanics for bridge design. Fracture mechanics are introduced and used as the basis for understanding fatigue and fracture in bridge structures. Various applications are cited