Title: Evaluation of Bond Strength of Bonded-In or Post-Installed Reinforcement

Author(s): Bilal S. Hamad, Rania Al Hammoud, and Jakob Kunz

Publication: Structural Journal

Volume: 103

Issue: 2

Appears on pages(s): 207-218

Keywords: anchors; bars; bond; strength; strut-and-tie modeling.

DOI: 10.14359/15178

Date: 3/1/2006

Abstract:
This paper reports on a research program conducted at the American University of Beirut (AUB) to assess the effect of several variables on the performance of frame nodes with cast-in and post-installed reinforcement, and thus to evaluate the performance of different injection systems used in bonding-in reinforcement. Eighteen fullscale specimens were tested in five sets. For each of two different bar sizes (12 or 14 mm), two different nominal concrete strengths (15 or 20 MPa), and three different embedment lengths (150, 250, or 290 mm), three or four companion specimens were tested in each set. The variables within each set were the installment history (pre- installed or post-installed), the anchorage type of the preinstalled or cast-in bars (hooked or straight), and the adhesive mortar used in the post-installing procedure. The test specimen simulated the rigid connection of two cantilever beams to a wall or column. An evaluation and comparison of cracking patterns, loaddeflection curves, and bond strength values indicated that postinstalled straight bars using appropriate adhesive mortars developed, in general, greater bond strength than companion cast-in straight bars, especially in the case of relatively shorter anchorage length. Also, test results indicated that ultimate strength of post-installed straight bars can be predicted with good precision by careful strutand-tie modeling of the node.