Experimental and numerical studies on the control of horizontal cracking at the ends of hollow-type pretensioned girders

Abstract

Recent bridge designs have created several efficient pretensioned prestressed concrete girder sections with high levels of prestress. Among them, hollow-type sections are of more consideration in Japan that exhibit good performance in practice. The transfer of large stresses from strands to concrete causes these sections to undergo horizontal cracking at the ends of the girders. To avoid such problem, this paper presents the implementation of various methods to the ends of two specimens prepared physically. Horizontal end cracks could not be fully eliminated by either of the methods in the selected type girder, but the method of enhancing end-zone reinforcement alongside strand-debonding could considerably decrease the principal stress that resulted in minimizing the cracks to a negligible level. To validate the experimental program, numerical models of the girder with identical parameters were simulated using the Finite Element Analysis software. Results obtained numerically well-matched the experimental ones to the extent of showing even the cracks pattern and vicinity.

Numerical study on the temporal changes of the principal stresses at the ends of the hollow PC-girders to control horizontal end cracks

“…The Von Mises model was used to model PC-strands and steel reinforcement bars. Based on the pre-analysis results (33) , bond stress and the threshold value of slippage for PC-strands are assumed to be 5.0 N/mm 2 and 0.2 mm, respectively. Constitutive laws of some materials used in this analysis are shown in Figure 5 .…”

Effects of the End-Zone Reinforcements and Strand-Debonding on the Temporal Changes of Principal Stresses at the Ends of the Hollow PC-Girders

“…These aspects make prestressed concrete ideal to provide high performance, economical, and an overall efficient highway bridge superstructure solution [4][5]. Over the years, however, there was a natural progression towards increasing the girder sizes and lengths to meet the design and economic constraints; this caused an increase in the number of strands in girder cross-sections leading to the end-zone cracking problems [6]. Horizontal end cracks have received good attention in the literature [7].…”

A comparative study on retrofitting concrete column by FRP-Wrapping and RC-Jacketing methods: A feasibility study for Afghanistan

“…These structures were bombed and subjected to different kinds of dynamic loads, which are still going on. Another reasons are; use of unstandardized and low-quality construction material, equipment, practices, overloading, aging, and corrosion, which significantly weakens even new structures and requires maintenance (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12) . Considering that building new structures in totality is costly and entirely out of Afghanistan's budget (and other third-world countries), a cost-effective strengthening method should be introduced.…”