Paper ID: 761

The Behavior of Glued-in Threaded Steel Rod Joints in Bangkirai Timber Beams Under Flexural Loading: Experimental and Numerical Investigations

 

Ali Awaludin^1,* & Miqdad Khosyi Akbar²

¹Department of Civil & Environmental Engineering, Faculty of Engineering, Gadjah Mada University, Indonesia

²Former Graduate Student, Department of Civil Engineering, Faculty of Engineering, Gadjah Mada University, Indonesia

 

*Corresponding author: ali.awaludi@ugm.ac.id

 

Abstract

This study aimed to examine flexural performance of Bangkirai timber beams jointed with glued-in threaded steel rods using epoxy-resin adhesive through experimental test and numerical analysis. A total of six beam specimens with varying rod diameters, anchorage lengths, and beam widths were subjected to four-point bending tests. The specimens included GIR B.65.16.17 (65 mm width, 16 mm rod diameter, 170 mm anchorage length), GIR B.65.12.25 (65 mm width, 12 mm rod diameter, 250 mm anchorage length), and GIR B.110.12.25 (110 mm width, 12 mm rod diameter, 250 mm anchorage length). The results showed that anchorage length significantly influenced moment capacity and stiffness of the beams. The highest average moment capacity was in GIR B.110.12.25 at 20.08 kNm due to its larger cross-section, while GIR B.65.12.25 showed a 58% higher moment capacity (16.57 kNm) than GIR B.65.16.17 (10.48 kNm). Elastic stiffness values were 538.60 kNm2, 809.44 kNm2, and 948.01 kNm2 in GIR B.65.16.17, GIR B.65.12.25, and GIR B.110.12.25, respectively, with longer anchorage lengths enhancing stiffness. The primary failure mechanism was epoxy-resin bond failure, leading to beam separation, while pull-out failure of steel rods was observed in some cases, particularly in specimens with shorter anchorage lengths. A 3-D nonlinear finite element analysis (FEA) was developed to validate experimental results. Differences between experimental and FEA results were within acceptable ranges, including 0.6-14.6% for elastic stiffness and 8.1-13.7% for moment capacity. Load-displacement curves obtained from the FEA correlated well with the experimental results, although the model slightly overestimated moment capacity due to the assumption of perfect epoxy-resin bonding. These results provided insights for optimizing glued-in rod timber joints in structural applications.

Keywords: bangkirai timber; epoxy-resin; finite element analysis; flexural performance; glued-in rods.

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