Negative bending tests on precast prestressed concrete beams made continuous

Abstract

The objective of the current study is to investigate and evaluate the flexural behavior of the continuity connection of precast prestressed concrete beams in negative bending when the tendons are located at the compression side. The experimental program included four T-shaped composite cantilever beams which were loaded up to failure. The main variable of the tests was the amount of prestress force of the connected precast beams. The reinforcement ratio of continuity connection was high. The ultimate flexural capacities and moment-curvature relations were calculated theoretically. A comparison was then carried out between both the experimental and theoretical results. These experiments revealed that prestress force did not influence the ultimate hogging moment capacity of the continuity connection, but it had an effect on its soffit's compression cracking and spalling of the concrete cover before failure. This study also indicated that confinement of the concrete had a massive influence on the connection's behavior, and it increased both its negative moment capacity and ductility.

Longitudinal shear in the tension flanges of composite concrete beams made continuous

“…Though this flange‐curl phenomenon is not a major effect, appreciable vertical deflections of unloaded flange outstands have been recorded in many tests 5,17,24,25 . The tested cantilever beams exhibited high longitudinal curvature values which are presented by Kytölä et al 1 …”

“…Though this flange-curl phenomenon is not a major effect, appreciable vertical deflections of unloaded flange outstands have been recorded in many tests. 5,17,24,25 The tested cantilever beams exhibited high longitudinal curvature values which are presented by Kytölä et al 1 Experimental results of the measurement frames indicate that some transverse deflections were also observed in these tests. Because of transverse deflections, only the shear strain of the measured cross sections B and C could be reliably determined according to the measurement frames DG-B5-6 and DG-C5-6.…”

“…Prestress at launching was 1350 MPa. Additional information (not vital for this study) about the test beams is presented by Kytölä et al 1 …”

“…This paper is part of a dissertation which purpose is to explore the potentials single span, prestressed concrete beams made continuous in heavily loaded parking deck structures. A recently published paper 1 is a part of the same dissertation and studies negative moment capacity of the structure.…”

“…After that, a plastic hinge started to form and its length extended to 400-800 mm away from the edge of central support. Detailed information about the test beam's negative flexural bending capacity is published by Kytölä et al1 Table…”