Behavior of unbonded posttensioning monostrand anchorage systems under monotonic tensile loading

Walsh, Kevin Q.; Kurama, Yahya C.

doi:10.15554/pcij.01012010.97.117

Cited by 33 publications

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“…The research by Walsh and Kurama [31][32][33] involved the testing of approximately 400 specimens of seven-wire, uncoated, low-relaxation posttensioning strand meeting ASTM A416 42 requirements with industry-representative standard anchorage components commonly available in the United States ( Fig. 1).…”

Section: Previous Researchmentioning

confidence: 99%

“…4 Furthermore, there was a large scatter in the strand ultimate strains at failure, representative standard strand-anchorage components from the United States was conducted by Walsh and Kurama. [31][32][33] Recently, premature strand wire fractures were also observed during the shake-table testing of a precast concrete building system. 34 Walsh and Kurama [31][32][33] showed that strand wire failures in industry-representative standard anchorage components can occur at strand strains as low as 0.01 or even smaller in some instances.…”

Section: Previous Researchmentioning

confidence: 99%

“…[31][32][33] Recently, premature strand wire fractures were also observed during the shake-table testing of a precast concrete building system. 34 Walsh and Kurama [31][32][33] showed that strand wire failures in industry-representative standard anchorage components can occur at strand strains as low as 0.01 or even smaller in some instances. The observed premature strand failures occurred due to the brittle fracture of individual strand wires inside the posttensioning anchors ( Fig.…”

Section: Previous Researchmentioning

confidence: 99%

“…Free-length failure tests of strand samples (that is, tensile tests performed using special sand-grip anchors to achieve strand failure within the free length away from the anchorages) conducted by Walsh and Kurama 31,32 showed that the true (that is, not affected by the anchorages) ultimate fracture strain capacity of seven-wire, low-relaxation posttensioning strand is generally between 0.060 and 0.075. Thus, the strain limit of 0.01 as governed by individual wire fractures inside the anchorages is restrictive relative to the actual material capacity of the strand.…”

Section: Previous Researchmentioning

confidence: 99%

“…A further breakdown of these results into different parameters can be found in Walsh and Kurama. 31,32 Additional testing conducted under postyield cyclic strand strain conditions showed that seismic loading can cause further reduction in the ultimate strand strains as well as further increase in the variation of these strains. 31,33 More recent cyclic testing of monostrandanchorage systems can be found in Sideris et al 35 It was provisionally observed by Walsh and Kurama 31 that the geometric properties of the wedges and anchors affected the ultimate performance of the tested strands.…”

Section: Previous Researchmentioning

confidence: 99%

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Effects of anchor wedge dimensional parameters on posttensioning strand performance

Walsh¹,

Draginis²,

Estes³

et al. 2015

pcij

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A lthough unbonded posttensioning for use in gravity load systems (for example, floor and roof slabs) has been available in the United States since the 1950s and standards exist for its application, 1-4 this construction method is increasingly being considered and applied in more extreme loading environments, such as in primary earthquake-resisting structural components (for example, primary shear walls and moment-resisting frames). Recent advances in the seismic application of unbonded posttensioning include precast concrete buildings, steel buildings, and bridge systems. [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] The posttensioning tendon anchorages in unbonded posttensioned building and bridge systems are important structural components because of the transfer of the entire posttensioning force at these locations. Posttensioning anchorage designs, configurations, manufacturing processes, and materials have significantly changed since the initial research that led to their development. [25][26][27][28][29] All of this early work focused on structures under gravity loads, with no consideration for extreme loads such as earthquakes. As a potential limitation for seismic applications, premature strand wire fractures were observed by Weldon and Kurama 30 during reversed-cyclic lateral load testing of unbonded posttensioned precast concrete coupled wall subassembly specimens. Subsequently, a detailed experimental study on the ultimate performance of industry-■ This paper reports on an experimental investigation of the effects of anchor wedge dimensions on the ultimate strains of posttensioning strand.■ The results demonstrate that slight increases in the taper angle of the anchor wedge outer surface and the thickness of the anchor wedge can significantly improve the ultimate performance of the strand at failure.

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Section: Previous Researchmentioning

confidence: 99%

Section: Previous Researchmentioning

confidence: 99%

Section: Previous Researchmentioning

confidence: 99%

Section: Previous Researchmentioning

confidence: 99%

Section: Previous Researchmentioning

confidence: 99%

See 3 more Smart Citations

Effects of anchor wedge dimensional parameters on posttensioning strand performance

Walsh¹,

Draginis²,

Estes³

et al. 2015

pcij

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Experimental research on the seismic properties of shear wall reinforced with high‐strength bars and magnetorheological dampers

Zhao

Ruan

et al. 2021

Structural Contr & Hlth

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Summary Magnetorheological (MR) damper was a kind of smart instrument, and it was very suitable for the semi‐active control. In this research, a large‐scale MR damper working in the shear mode of the MR fluid was developed to enhance the mechanical properties of the shear wall. The influence of MR damper on the mechanical properties of the shear walls, such as stiffness, strength, ductility, and the energy dissipation capacity, had been researched. Firstly, both the model of MR damper and shear wall were established to optimize the properties of the MR damper and shear wall. Then, three different concrete shear walls were fabricated, which were reinforced by carbon fiber‐reinforced polymer (CFRP) bars (W‐1), CFRP bars and MR dampers (W‐2), and steel strands and MR dampers (W‐3), respectively. The mechanical properties of the specimens were experimentally researched and analyzed. The experimental results showed that the ductility, the ability to bear external loads, stiffness, and energy dissipation capacity of the shear walls could be enhanced by the MR damper simultaneously. Compared with W‐1, the ductility, the ability to bear external loads, ultimate deformation, and energy‐dissipation capacity of W‐2 increased by 4.1%, 26.8%, 83.9%, and 35.8%, respectively. The residual deformation of the three shear walls was almost the same. The results indicated that the MR damper could enhance the mechanical properties of the shear walls and had no influence on the self‐centering capacity of the shear walls at the same time.

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Experimental investigation of a locally prestressed precast concrete wall

Zhang

Qing

Wang

et al. 2022

Structural Concrete

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The posttensioned (PT) tendons in a prestressed precast wall (PPW) may suffer yielding or damage under rare earthquake events, increasing the potential demand for their maintenance and renewal. A locally PPW (LPPW) with PT tendons arranged only in the lower stories was developed in this article to facilitate the replacement of the PT tendons. Quasi-static tests were conducted to investigate the seismic performance of the LPPW with and without additional energy dissipaters. The test results demonstrated that the LPPW featured a stable hysteretic response and an excellent self-centering capacity. The dissipaters effectively improved the energy dissipation capacity of the LPPW and preserved its self-centering capacity. Numerical studies were further performed to address the influence of the layout of the PT tendons and dissipaters. The numerical results showed that reducing the height of the upper anchorage points of the PT tendons could increase the bearing capacity and postyielding stiffness of the LPPW. The concrete contact force at the base joint could be reduced by about 40% by moving the dissipaters from center to edge regions of the cross-section of the wall.

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Behavior of unbonded posttensioning monostrand anchorage systems under monotonic tensile loading

Cited by 33 publications

References 0 publications

Effects of anchor wedge dimensional parameters on posttensioning strand performance

Effects of anchor wedge dimensional parameters on posttensioning strand performance

Experimental research on the seismic properties of shear wall reinforced with high‐strength bars and magnetorheological dampers

Experimental investigation of a locally prestressed precast concrete wall

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