Manfred A. Hirt

Fatigue crack propagation in steels

Keywords: 108/ICOM Reference ICOM-ARTICLE-1983-005doi:10.1016/0013-7944(83)90070-XView record in Web of Science Record created on 2008-01-24, modified on 2016-08-08

FATIGUE CRACK GROWTH IN WELDED BEAMS

The fatigue behavior of welded steel beams is evaluated using the fracture mechanics concepts of stable crack growth. A fracture mechanics model for cracks originating from the pores in the web-to-flange fillet weld is developed. Estimates of the stress-intensity factor are made that numerically describe the initial flaw condition. With the final crack size known, a theoretical crack-growth equation was derived from the fatigue test data of the welded beams. The derived relationship compares well with actual crack-growth measurements on a welded beam and available data from crack growth specimens. The regime of crack growth where most of the time is spent growing a fatigue crack in a structural element is shown to correspond to growth rates below ten to the minus six in. per cycle. Little experimental crack growth data is available at this level. It is concluded that the fracture mechanics concepts can be used to analyze fatigue behavior and to rationally evaluate the major variables that influence the fatigue life of welded beams.

Size effect of welded thin-walled tubular joints

This paper clarifies the terminologies used to describe the size effect on fatigue behavior of welded joints. It summarizes the existing research on size effect in the perspective of newly defined terminologies. It identifies knowledge gaps in designing tubular joints using the hot spot stress method, i.e. thin-walled tubular joints with wall thickness less than 4 mm and thick-walled tubular joints with wall thickness larger than 50 mm, or diameter to thickness ratio less than 24. It is the thin-walled tubular joints that are addressed in this paper. It is found that thin-walled tube-plate T-joints do not follow the conventional trend: the thinner the section is, the higher the fatigue life. It is also found that simple extrapolation of existing fatigue design curves may result in unsafe design of thin-walled tube–tube T-joints. The effect of chord stiffness on fatigue behavior of thin-walled tubular T-joints is also discussed.

Probability-based load models of highway traffic

Keywords: 252/ICOM Reference ICOM-ARTICLE-1991-002doi:10.2749/101686691780617797 Record created on 2008-01-24, modified on 2016-08-08

Tubular Trusses for Steel-Concrete Composite Bridges

Keywords: 585/ICOM Note: CD Rom, Paper A-0551 Reference ICOM-CONF-2007-005 Record created on 2008-01-24, modified on 2016-08-08

Modern tubular truss bridges

Keywords: 465/ICOM Note: CD-ROM Reference ICOM-CONF-2002-005 Record created on 2008-01-24, modified on 2016-08-08

The Future of IABSE

ing and Indexing: This publication is abstracted quarterly in Cambridge Scientific Abstracts under CSA Civil Engineering Abstracts: www.csa.com/engineering, at Emerald Abstracts, International Civil Engineering Abstracts: www.emeraldinsight.com/abstracts, at Construction and Building Abstracts (CBA): http://www.cbaweb.co.uk/

Probability Based Load Models of Highway Traffic for ULS and SLS Analyses

This paper presents a probability based concept for the modeling of highway traffic loads which includes the effects of dead load, live load and the resistance of the structure. It consists of the following parts: the principles of traffic simulation, the concept of the probabilistic analysis of ultimate limit state (ULS), the load models obtained for ULS, the particular problems for the analysis of serviceability limit state (SLS). The results of this study show that it is possible to justify, on a probabilistic basis, load models for highway traffic which assure a uniform degree of safety for different structures and which are independent of type of material, type of cross section and other structural characteristics such as span length and deck width.