Experimental Study on the Bending Properties of Grouting Butt Joints Reinforced by Steel Plate Embedded in Bamboo Tube

Ting Huang,Xin Zhuo

doi:10.32604/jrm.2022.017373

Abstract

The construction of grouting butt joints of bamboo tubes is simple and efficient. However, when the joint is bent, the low tensile strength of the mortar easily leads to cracking of the mortar prior to the failure of the bamboo tube. In this paper, a comparative test of the bending capacity was performed on grouting butt joints reinforced by nonperforated, fully perforated, and semiperforated steel plates embedded in bamboo tubes to obtain the load-displacement curves and ultimate bearing capacity of various specimens. The strengthening effect of CFRP pasted on bamboo tubes was also studied. The results show that the opening at the end of the steel plate is beneficial to resist the slip between the mortar and steel plate, while the complete section in the middle of the steel plate is conducive to making full use of the tensile strength of the steel plate. Therefore, it is best to insert the semiperforated steel plate with openings in the end and without openings in the middle into the mortar to enhance the bending properties of the grouting butt joint, which can make the failure mode of the joint change from brittle failure of mortar to ductile compression failure of bamboo tube. In addition, pasting CFRP sheets on the external wall of the bamboo tube helps to reduce the tensile stress of the mortar, while increasing the width of the steel plate can increase the bending moment of inertia of the mixture of the steel plate and mortar. These two complementary measures are very effective in delaying the cracking of the bamboo tube and improving the bending capacity of the joint.

Highlights

Bamboo is the most important nontimber renewable forest product in the world, possessing a short growth cycle and strong carbon sequestration capacity [1]
The steel plate at the splitting end of the mortar contacts the internal wall of the bamboo tube, and the curve continues to rise until the steel plate splits the bamboo tube and the specimen is destroyed
The reason why the curve of specimen B1–1 fluctuates greatly in the early stage is that the bamboo tube is elliptical and the preset loading direction does not coincide with the center of gravity of the specimen, which leads to the deviation of the specimen position in the loading process

Summary

Introduction

Bamboo is the most important nontimber renewable forest product in the world, possessing a short growth cycle and strong carbon sequestration capacity [1]. Rui [16] conducted an experimental study on the bending properties of grouting butt joints of bamboo tubes. It was a singlepoint loading test with concentrated force in the middle of a supported beam and the distance between the supports was 600 mm. Morisco [17] proposed a steel plate butt joint, the outer surface of which was connected by a steel plate and bolt, and the cavity of the bamboo tube was reinforced by injecting cement mortar. The steel plate is used because of its great flexural strength in the strong axis direction and easiness to bend in the weak axis direction, which makes the mass-produce of bamboo tube triangle with any angle easy and convenient. The bending properties of grouting butt joints reinforced by nonperforated steel plates, semiperforated steel plates and fully perforated steel plates and the reinforcement effect of CFRP sheets and iron wires are studied by contrast experiments

Materials and Methods

Semiperforated 5

Conclusions