A STUDY ON EVALUATION OF RESTORING FORCE CHARACTERISTICS OF TENSILE BRACE SHEAR WALL USING L－SHAPED BRACE CONNECTOR

Abstract

 A braced shear wall is an important shear resistant element in post and beam construction in Japan. Braced shear walls have better work-ability than nailed plywood shear walls and easier to install ventilation holes and piping holes. Also, it has advantages such as high wall magnification can be obtained by using in combination with plywood, it is widely used in wooden houses.

 Though many studies have been done on the static structural performance of braced shear walls, it was difficult to predict the load- story displacement relationship of the braced shear wall on tensile direction. In this study, focused on the braced shear wall using L-shaped brace connectors that connect the ends of a brace and columns, which have become popular in recent years, static shear loading tests of the single-braced shear wall specimens were conducted. Variables of the specimens were the wall length, the thickness of the L-shaped brace connector, the number and the length of screws.

 Then, an analysis model of the braced shear wall with the L-shaped brace connectors was proposed and static pushover analyses were conducted. The analysis result showed close to the load-displacement relationship of the experiment up to about 1/50 rad.

 From the static shear loading tests and the pushover analyses, following findings were obtained.

 

 a) As the thickness of the L-shaped brace connector increases, the shear strength of the braced shear wall increases and the ultimate displacement decreases.

 b) Effect of the number of the screws on the column on the shear strength of the braced shear wall is small in the case of 910mm of wall length. However, in the case of 1365mm and 1820mm of wall length, since a ratio of the horizontal component of the axial tensile force of the brace to the vertical component of the one increases, it affects the shear strength.

 c) With long screws on the column, the maximum shear strength of the braced shear wall increases. However, there is possibilities of pulling-through the screw from the connector or splitting failure of the column. Therefore, the higher pull-out strength of the long screw may not affect the maximum strength.

 d) Even if the number of screws on the brace side increases, the influence on the shear strength of the braced shear wall is small due to cracks on the end of the brace. If the cracks on the brace do not occur, the maximum shear strength of the braced shear wall is considered to increase.