73 research outputs found
A Report of the Investigation on Steel Bridge Design Criteria to Help Minimize the Probability of Fracture; Project IHR-304, Illinois Cooperative Highway Transportation Research Program
In this study the nature of actual random traffic stress histories in
steel beam or girder highway bridges has been investigated. Quantitative
field test results have been used to develop mathematical models that can
be used to represent the stress histories for such bridges.
The beta distribution function has been found to be an effective
mathematical model for the actual stress-range histograms and has been
used to establish random stress factors and can be used in fatigue design
to account for the random nature of loadings in highway bridges.State of Illinois. Department of TransportationU.S. Department of Transportation. Federal Highway Administratio
Report on Phase 2.3, Investigation of Welded Highway Bridges. Project IHR-64
The object of this investigation was to study the effect of internal flaws
on the fatigue behavior of butt-welded connections in mild structural steel, the
initiation of fatigue cracks from these flaws and the propagation rates of these
cracks in the connections. Since internal flaws occur in many welds it is essential
to obtain a better understanding of the behavior of flawed connections so that adequate,
yet realistic, code requirements can be established.
The study is limited to two major types of defects, porosity and incomplete
penetration. The porosity was further subdivided into two categories based on
the severity of the defect. The specimens with incomplete penetration were made
with an initial 3/16" centrally located crack the full width of the- specimen.
The fatigue behavior of the connections with the defects is compared with
that of sound welds to observe the effects of the defects on the fatigue strength
of the connections. The data are compared with result~ of similar studies found in
the literature and also with the AASHO 1970 Specification design requirements.
Three of the specimens with incomplete penetration were examined radiographically
during the fatigue testing to determine when initiation of the fatigue
cracks occurred, and how rapidly they propagated. The results of the crack propagation
tests are compared with similar relationships developed for high strength
steels. A relationship that better fits the data for mild steel has been developed
in a manner similar to that used for the high strength steels.State of Illinois. Department of Transportation. Division of HighwaysU.S. Department of Transportation. Federal Highway Administratio
Fatigue Behavior of Welded Joints and Weldments in HY-80 Steel Subjected to Axial Loadings
Bureau of Ships, U.S. Navy.Contract N0bs 77137Index No. NS-021-20
Evaluation of Flow and Fracture Propensity of Notched Steel Plates by Means of a Photoelastic Model
Ship Structure Committee. Bureau of Ships, U.S. Navy.Contract NObs 88283Project Serial No. S-F 013 0304, Task 2022Project SR-14
Effect of Notches on the Axial Fatigue Properties of Structural Steels
The effect of the stress concentration on the zero-to-tension axial fatigue
strength of notched members of four structural steels has been studied. For
each of the four steels a critical notch severity was found at which a transition
in behavior takes place. When the theoretical stress concentration exceeds this
critical value the fatigue strength increases instead of continuing to decrease as
would normally be expected. The maximum effective stress concentration determined
from these tests corresponds to a critical notch severity which is dependent on the
material) the geometry of the specimen) and the cyclic conditions of stress.
Microscopic examinations of the roots of the notched specimens which did
not fail revealed cracking in most cases. Some of the cracks apparently were nonpropagating
cracks but the test lives in most cases were insufficient to isolate
such cracks positively as non-propagating. A study of other data on non-propagating
cracks revealed that the laws governing their formation are not yet fully
understood. However, there are indications that the increase in fatigue strength
obtained above the critical notch severity is coincident with the formation of
non~propagating cracks.The Engineering FoundationAmerican Iron and Steel InstituteChicago Bridge and Iron FoundationThe Welding Research Counci
Tests of Welded Copper Joints
The Copper and Brass Research Associatio
Effect of Repeated Loads on the Low Temperature Fracture Behavior of Notched and Welded Plates
The influence of repeated loadings on the susceptibility of weldments
to fracture in a brittle manner is studied for an ABS-Class C steel.
The test members have consisted primarily of 12, 24 and 36 in. wide notched-and-
welded specimens that, at low temperatures, have been known to provide low-stress brittle fractures.
The repeated loads or loading history are found to affect the
fracture behavior of the weldments. In all but one instance the fracture stresses obtained for the notched-and welded wide plates were greater than the stresses to which the members had been subjected during the repeated
loadings. Furthermore, the repeated loadings appeared to eliminate the two-stage fractures observed in some of the tests of as-welded specimens. This latter condition is in general desirable, but only if the fracture stress is raised to a high-stress level.Bureau of Ships - Department of the Navy Contract NObs 88283 Proj ect SR-149 Ship Structure Committe
Fatigue and Static Properties of Welded Joints in Low Alloy Structural Steels
Ohio River Division LaboratoriesCorps of Engineers, U.S. Army.Contract No. DA-33-eng-25
Crack Propagation in Low-Cycle Fatigue of Mild Steel
Ship Structure Committee. Bureau of Ships, U.S. Navy.Contract NObs 77008Index No. NS-731-034Project SR-14
Effects of Repeated Loadings on Structural Connections with High-Strength Bolts
Research Council on Riveted and Bolted Structural JointsThe Division of Highways. State of Illinois.The Bureau of Public Roads. U.S. Department of CommerceProject I
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