Mechanical Properties of Thai Dendrocalamus Bamboo Column Joints

The Joint is considered an essential component in construction. In the paper, study the compressive strength tests of standard-sized of the Thai Dendrocalamus Giganteus bamboo laminated columns that connected in 3 different joints. The test results show that column type 3 joints can withstand the highest compressive strength of 12333 kgf. From the test results show that bamboo columns that are connected. The force is reduced by approximately 90 percent compared with the column without the joint. Keywords—Dendrocalamus Gigantues; joint ; compressive strength

INTRODUCTION Thai Dendrocalamuus Giganteus (TDG) Bamboo is the giant bamboo in Thailand that can grow anywhere around Thailand. TDG bamboo at age 3-years form Ta Wong Pa district of Nan province, cut from the bottom 6 meters long and divided into 3 parts ;bottom middle and top each part cut 2 meters long. The physical properties of the 3-year-old TDG bamboo, the test results as following by [1] [2][3] [4] [5] can be summarized as follows 1. TDG bamboo at the bottom part with an average circumference of 48.64 centimeters and an average thickness of 2.86 centimeters.
2. TDG bamboo in the middle part of the bamboo with an average circumference of 43.42 cm and an average thickness of 1.43 cm.
3. TDG bamboo in the top part of the bamboo with an average circumference of 39. 27 cm and an average thickness of bamboo of 0. 7 9 cm. TDG bamboo laminated have been studied by [6] [7][8] the analysis of the mechanical properties; compressive strength, bending and shear according to the test by ASTMD 143-09 [9] and DPT 1221-51 [10] the test results can be summarized as follows A. Compressive strength of TDG laminated column TDG bamboo laminated column for this paper study the factor of temperature and moisture that affect the compressive strength. [7] The compressive strength of bamboo column size standard 50×50×200 mm total 3 pieces test the factor that affects the compressive strength in 2 cases; sink in the water for 48 hours. The results of the test shown that TDG column got the water absorption very slow, as shown in table 1. MA2 code for the specimens without a soak in the water with moisture content 7% compared with the MA1 sink in the water 24 hours the moisture content to 21.20% and MA3 sink the water 48 hours with the moisture content 26.30 %. For this study, the results of the increased moisture content affect the load properties because of the failure of the adhesion. Another case study of temperature affects the bearing capacity of bamboo poles; found that the temperature at 0 degrees Celsius and 60 degrees Celsius is not very different. Then shows that the change of temperature does not affect the strength of bamboo. The study found that TDG bamboo laminated column can be classified as a hardwood.  . TDG bamboo beam classified as a hardwood. From the study of mechanical properties of processed TDG bamboo, found that bamboo can be used to replace wood in the future. Therefore, this research studied the joint of structural bamboo columns. So that TDG bamboo can be used widely.

II. RESEARCH OBJECTIVES
The scope of a study; TDG bamboo used for experimental taken from Tha Wang Pha district of Nan province, at age 3 years. The TDG culms measured above 6 meters from the bottom culms and cut into 2 meters long set the code to 3 part; bottom middle and top. In this paper, the TDG bamboo laminated column made from the bottom part. The design of the TDG column lay with horizontal fiber as shown in fig 1.

III. MATERIALS AND METHODS
In this study, TDG bamboo aged 3 years immersed in water for 10 days and dry them with the solar kiln house 1-2 months. After the bamboo turns into yellow color, cut the bamboo to make the strip as shown in fig. 2 the size of the strip width 3 cm and long 2 meters. Fig. 2 the strips making the process The stripping process takes approximate 3 months and checks for moisture content in the strip, not over 12 % [13].The following processes are essential as follows.

A. TDG bamboo laminated column forming process
The strips from the bottom part are glued together to the size standard 50×50×200 mm. The strip glue and clamp for more than 8 hours after that cut to size, as shown in fig 3. All the specimens after glue let them dry for 1 month before testing the mechanical properties. To allow the glue to dry and complete adhesion.In this paper, Most of the production processes are manual production and general woodworking tools

B. TDG bamboo laminated Joint making process
The joints in the paper design in 3 types. The pattern of the joint design in the paper and draw in the TDG column after that cut to size with a jigsaw along with the pattern as shown in             However, the strength of the joint also depends on other factors such as the meticulousness of the process to make the joints, the time to let the glue dry as well as type of glue used in production.