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Robert J. Dexter

Other affiliations: HNTB
Bio: Robert J. Dexter is an academic researcher from University of Minnesota. The author has contributed to research in topics: Fracture mechanics & Girder. The author has an hindex of 16, co-authored 42 publications receiving 764 citations. Previous affiliations of Robert J. Dexter include HNTB.

Papers
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Journal Article
TL;DR: In this article, a study on fatigue resistance of cantilevered signal, sign, and light supports is presented, and recommended specifications for the fatigue-resistant design of these structures are included.
Abstract: This report contains the findings of a study on fatigue resistance of cantilevered signal, sign, and light supports. Recommended specifications for the fatigue-resistant design of these structures are included. The contents of this report will be of immediate interest to bridge and structural engineers, traffic engineers, and manufacturers. The research determined that, for a typical sign or signal support structure, galloping is the primary cause of vibrations that may result in fatigue damage. It was also determined that the number of structures observed to be galloping in field applications is low. Much variation in the detailing of connections was found, and several details of low fatigue resistance are in use. The research suggests that, through changes in the recommended design wind loads used for design of these structures and avoidance of fatigue-susceptible details, the probability of failure of these structures may be reduced. In addition, the research suggests that mitigation of wind-induced vibrations of structures, once they are observed in the field, may also be a desirable action. The report recommends additional research in this area and provides guidance that designers may consider pending any formal changes to design specifications by the American Association of State Highway and Transportation Officials.

135 citations

Journal Article
TL;DR: In this article, a survey of bridge owners and consulting engineers engaged in the design, inspection, and management of bridges with fracture-critical details is presented as a guide to present specifications and engineering judgment.
Abstract: This synthesis may be useful to bridge owners and consulting engineers engaged in the design, inspection, and management of bridges with fracture-critical details, as a guide to present specifications and engineering judgment. It focuses on the inspection and maintenance of bridges with fracture-critical members (FCMs), as defined in the AASHTO "LRFD Bridge Design Specifications." The objectives of this report were to survey and identify gaps in the literature; determine practices and problems with how bridge owners define, identify, document, inspect, and manage bridges with fracture-critical details; and identify specific research needs. Among the areas examined were: inspection frequencies and procedures; methods for calculating remaining fatigue life; qualification, availability, and training of inspectors; cost of inspection programs; instances where inspection programs prevented failures; retrofit techniques; fabrication methods and inspections; and experience with FCM fractures and problems details. This synthesis contains information obtained from a survey distributed to bridge owners and consultant inspectors (72 state, provincial, and international departments of transportation and agencies), a literature search, and targeted interviews. Useful responses were received from 34 states and three Canadian provinces.

63 citations

01 Mar 2013
TL;DR: In this article, the consensus best practices for repair and retrofit of fatigue cracks in steel bridges as of 2010 are presented, as well as a guide for owners and consulting engineers to use for design and detailing of repairs and retrofits for fatigue cracks.
Abstract: This manual is a synthesis of published literature as well as the collective experience gathered from participants of a workshop held at Lehigh University August 14-15, 2002. It presents what are the consensus best practices for repair and retrofit of fatigue cracks in steel bridges as of 2010. The manual is also a guide for owners and consulting engineers to use for design and detailing of repairs and retrofits for fatigue cracks. It should be used in conjunction with existing specifications, codes, and engineering judgment.

54 citations

Journal ArticleDOI
TL;DR: In this article, cyclic tension fatigue tests were conducted on approximately half-scale welded stiffened panels to study propagation of large cracks as they interact with the stiffeners, and a linear elastic fracture mechanics analysis was used, to simulate the crack propagation, and gave reasonable agreement with the experiments.

50 citations


Cited by
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Journal ArticleDOI
01 Jan 1966-Nature
TL;DR: Adhesion and AdhesivesEdited by Dr. R. Houwink and Dr. G. Salomon.
Abstract: Adhesion and Adhesives Edited by Dr. R. Houwink and Dr. G. Salomon. Vol. 1: Adhesives. Second, completely revised edition. Pp. xvi + 548. (Amsterdam, London and New York: Elsevier Publishing Company, 1965.) 135s.

348 citations

Book ChapterDOI
01 Jan 1999
TL;DR: In this article, the suitability and uncertainty of physical models were considered for crack initiation and growth under cyclic loading as well as unstable crack propagation and tearing in ship and offshore structures and due attention was paid to practical application and statistical description of fracture control methods in design, fabrication and service.
Abstract: COMMITTEE MANDATE Concern for crack initiation and growth under cyclic loading as well as unstable crack propagation and tearing in ship and offshore structures. Due attention shall be paid to practical application and statistical description of fracture control methods in design, fabrication and service. Consideration is to be given to the suitability and uncertainty of physical models. The work shall be coordinated with that of Committee V.2.

218 citations

Journal Article
TL;DR: In this article, a study on fatigue resistance of cantilevered signal, sign, and light supports is presented, and recommended specifications for the fatigue-resistant design of these structures are included.
Abstract: This report contains the findings of a study on fatigue resistance of cantilevered signal, sign, and light supports. Recommended specifications for the fatigue-resistant design of these structures are included. The contents of this report will be of immediate interest to bridge and structural engineers, traffic engineers, and manufacturers. The research determined that, for a typical sign or signal support structure, galloping is the primary cause of vibrations that may result in fatigue damage. It was also determined that the number of structures observed to be galloping in field applications is low. Much variation in the detailing of connections was found, and several details of low fatigue resistance are in use. The research suggests that, through changes in the recommended design wind loads used for design of these structures and avoidance of fatigue-susceptible details, the probability of failure of these structures may be reduced. In addition, the research suggests that mitigation of wind-induced vibrations of structures, once they are observed in the field, may also be a desirable action. The report recommends additional research in this area and provides guidance that designers may consider pending any formal changes to design specifications by the American Association of State Highway and Transportation Officials.

135 citations

Journal ArticleDOI
TL;DR: In this article, the effect of low stress cycles on the fatigue and service life is considered by modifying the stress range when it is less than a limit value of stress range, and the influence of updating on the calculation of fatigue damage and predicted service life was numerically investigated.

123 citations

Journal ArticleDOI
TL;DR: In this article, a rational approach is proposed to model the hysteretic behavior of fully restrained composite beam-to-column connections, with reduced beam sections, and a system-level analytical study is performed on archetype steel buildings that utilize perimeter steel SMFs, with different heights, designed in the West Coast of the USA.
Abstract: SUMMARY: This paper investigates the effect of the composite action on the seismic performance of steel special moment frames (SMFs) through collapse. A rational approach is first proposed to model the hysteretic behavior of fully restrained composite beam-to-column connections, with reduced beam sections. Using the proposed modeling recommendations, a system-level analytical study is performed on archetype steel buildings that utilize perimeter steel SMFs, with different heights, designed in the West-Coast of the USA. It is shown that in average, the composite action may enhance the seismic performance of steel SMFs. However, bottom story collapse mechanisms may be triggered leading to rapid deterioration of the global strength of steel SMFs. Because of composite action, excessive panel zone shear distortion is also observed in interior joints of steel SMFs designed with strong-column/weak-beam ratios larger than 1.0. It is demonstrated that when steel SMFs are designed with strong-column/weak-beam ratios larger than 1.5, (i) bottom story collapse mechanisms are typically avoided; (ii) a tolerable probability of collapse is achieved in a return period of 50years; and (iii) controlled panel zone yielding is achieved while reducing the required number of welded doubler plates in interior beam-to-column joints. © 2014 John Wiley & Sons, Ltd.

109 citations