Numerical Evaluation of the Shear Behavior of a Metal Shear Key Used in Joining Precast Concrete Segmental Bridge Girders without Epoxy

Abstract

The shear key is an important part of a precast segmental concrete bridge. Aside from its function of contributing to the distribution of shear force from one concrete segment to another, it helps to join precast concrete segments to become a complete bridge structure and provide continuity of movement for vehicles and pedestrian traffic. This numerical study discusses the behavior of a full-scale shear key connection without epoxy joining two concrete blocks representing segmental precast concrete at which two external forces load the blocks. Ferro Casting Ductile (FCD) is used as the metal shear key material where the shear key consists of two parts, a male and a female shear key. Numerical simulation is conducted using the ANSYS academic package, with nonlinear analysis implemented accordingly. The appropriate constitutive materials in relation to the numerical program, both for concrete and FCD, are taken from the appropriate literature. Two criteria are employed in the study; failure of the concrete block and yielding of the shear key that follows the von Mises criterion. Shear key connection system capacity is evaluated by applying different magnitudes of horizontal force. The validation of two numerical simulation studies is conducted by two experimental programs that cover laboratory experimentation of full-scale shear keys connecting two concrete blocks. The numerical and experimental results produce an almost similar relation of shear stress at the male shear key and vertical displacements of the upper block relative to the lower concrete block. Finally, a contour of shear key shear stress as a function of the different magnitudes of equivalent prestressing and different quality of concrete compressive strength is proposed.

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“…The non-linear analysis is made to simulate similar experimental test setup in pre-vious studies (Purnomo et al, 2017;. The configuration of the test setup of precast concrete girder uses two concrete blocks as shown in Figure 1.…”

“…The Japanese standard (Japan Society of Civil Engineering, 2007) recommends the use of FCD (ferro casting ductile) metal with grade 450 as a material for FCD shear keys. The Japa-nese standard's recommendation was verified by Purnomo et al (2017) in their ex-periment. Purnomo et al (2017) found that shear keys with grade 450 have higher shear strength with the smallest displacement than any other FCD metal with grade range from 265-274 MPa (Compression yield stress).…”

“…The Japa-nese standard's recommendation was verified by Purnomo et al (2017) in their ex-periment. Purnomo et al (2017) found that shear keys with grade 450 have higher shear strength with the smallest displacement than any other FCD metal with grade range from 265-274 MPa (Compression yield stress). Purnomo et al (2018) have conducted experiments with specific geometry shear key and different geometry shear keys.…”

Flexural Behavior of Precast Concrete Segmental Box-Girders with Dry Joints

“…Precast concrete segmental (PCS) girders have been widely applied in mid-/long-span bridges due to their rapid assembly, excellent quality control, low life-cycle cost, and mitigated environmental disturbance. In the past decades, extensive studies were conducted on PCS girder bridges concerning the shear strength of epoxy and dry joints with various geometries [1][2][3][4][5]. It was observed that the average shear strength in multiple-keyed dry joints is less than that in single-keyed dry joints in view of imperfections in occlusion of keys [1] and the failure of the epoxied joints was brittle [2].…”

“…Alcalde pointed out that as the number of shear keys increases, shear stress across the joint decreases [3]. Numerical evaluation of the shear behavior of a Ferro Casting Ductile (FCD) metal shear key [4] indicated that a combination of high-quality concrete and higher prestressing force would be safer when a FCD shear key is applied in segmental dry joints. Additionally, it is observed that shear capacity of the joints increased by approximately 40% as the confining stress increased by 50% [5].…”