This research (which is the second phase of a study intended to provide reliable information on fatigue behavior of steel bridge members), and an extensive investigation of fatigue effects in welded steel beams, which formed the basis for recommendations for revision of the fatigue provisions of the AASHP Standard Specifications for Highway Bridges. A hundred and fifty seven steel beams and girders were fabricated and tested to define the fatigue strength of various structural details, including stiffeners and attachments. Stress range was observed for nearly all the variation in cycle life for all stiffener and a attachment details examined in this study.

Fatigue is a mechanism of failure which involves the formation and growth of cracks under the action of repeated stresses. Ultimately, a crack may propagate to such an extent that total fracture of the member may occur. To avoid fatigue it is essential to design the structure with inherent fatigue strength. However, fatigue strength for variable amplitude loading is not a constant material property and any calculations are necessarily built on a number of assumptions. Cumulative damage of welded joints explores the wealth of research in this important field and its implications for the design and manufacture of welded components.After an Introduction, chapter two introduces the constant amplitude database, which contains results obtained in test conditions and which forms the basis of the basic S-N curves for various types of joint. Chapter three discusses the influence of residual stresses which can have a marked effect on fatigue behaviour. Chapter four explores variable amplitude loading and the problem of how information from laboratory tests, obtained under constant amplitude conditions, can be applied to the design of structures for service conditions. This problem is further investigated in the next chapter which is devoted to two and three level load testing. Chapters six, seven and eight look at the influence that the variety of variable loading spectra can have on fatigue strength, whether narrow or wide band loading or cycles of small stress range. Taking all of this knowledge, chapter nine discusses structure designs.Cumulative damage of welded joints is a comprehensive source of invaluable information for welding engineers, supervisors, inspection personnel and designers. It will also be of great interest for academics working in the fields of structural and mechanical engineering. Covers the wealth of research in the field of fatigue strength and its role in the design and manufacture of welded components Invaluable reference source for welding engineers, supervisors, inspection personnel and designers

The paper summarizes some of the findings of a comprehensive study on the fatigue strength of rolled and welded built-up beams without attachments, rolled and welded beams with cover plates, and welded beams with flange splices. Altogether, 374 steel beams with two or more details were fabricated and tested. The welded beam details discussed herein represent the upper and lower boundaries of fatigue behavior of welded beams. The lower bound is provided by beams with partial length cover plates - a severe notch producing details. For purposes of design, this study has shown that the fatigue strength of the upper and lower bound details is independent of the strength of steel. A36, A441 and A514 steel beams provided the same fatigue strength for a given detail, and stress range was observed to account for nearly all the variation in cycle life. The paper reviews briefly the major variables that influence the fatigue strength of welded details and suggests how they should be considered in design. (Author).