Push-out fatigue tests of the Alternate Shear Connector
Date
1998
Authors
Siow, Yuen-Shuenn
Major Professor
Advisor
Klaiber, F. Wayne
Wipf, Terry J.
Committee Member
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
A modification of a bridge replacement system, known as the beam-in-slab-bridge (BISB) has led to an investigation of a new shear connector for steel-concrete composite structures. The new shear connector, known as the Alternate Shear Connector (ASC), was tested to determine its static strength and behavior using push-out tests with variables such as hole diameter, hole spacing, and the presence of reinforcement in the holes. Composite beam tests, which consisted of service and ultimate load tests, were also performed to determine the effectiveness of the connector as a modification to the steel beams currently used in the BISB system. In this study, push-out tests were completed to determine the relationship of the fatigue stress and the fatigue life of the shear connector as well as the slip behavior of the connector during its fatigue life. A total of 27 push-out specimens were fabricated and tested to failure.
Of the 27, six were tested statically to determine the ultimate static strength of the connector. The fatigue tests were conducted at various maximum load levels that corresponded to various percentages of the ultimate static strength. Three different shear hole arrangements were investigated to determine their effect on the fatigue strength. Variables such as alignment of shear holes and placement of reinforcing bars through the shear holes were evaluated. A mathematical model expressing the logarithm of the fatigue life as a linear function of the logarithm of the maximum load level was determined from the test data. In this relationship, the maximum load level was expressed in terms of percent of the ultimate static strength. Using regression analyses, the number of cycles attained for specimen tested in fatigue at 80 percent and 69 percent of the ultimate strength were 8,954 and 475,227 cycles, respectively.
Fatigue strength of the ASC was 69 percent of the ultimate static strength at 500,000 cycles loading, which was approximately 16 percent higher than the horizontal shear found in a single span bridge using typical design conditions. The S-N curves indicated that the connectors gained minimal strength when the shear hole alignment was staggered. It was determined that the fatigue strength increased when reinforcing bars were included in the half-circled shear holes, rather than being placed in the half-circled shear holes on the edge of the steel plates.
Series Number
Journal Issue
Is Version Of
Versions
Series
Academic or Administrative Unit
Type
thesis