Static Axial Reciprocal Load Test of Cast-in-place Nodular Concrete Pile and Nodular Diaphrgm Wall

Abstract

In recent years, both tension force and compression force occur in foundation such as pile foundation or wall foundation due to earthquake and wind loads with increasing building height and building weight. In addition, tension loads on foundation can increase also as groundwater table rises. This trend is noticeable especially in urban central areas of Japan. From these backgrounds, it is necessary to develop new types of foundations for high-rise superstructures. New types of foundation are nodular cast-in-place concrete pile or nodular diaphragm wall with one- or two-bell shaped enlargements to increase both bearing capacity and tension resistance. The main purpose of this study is to confirm the resistance of nodular cast-in-place concrete pile and nodular diaphragm wall in clayey soils. The paper reports the investigation of construction methods of nodular cast-in-place concrete pile and nodular diaphragm wall, and the results of static axial reciprocal load tests carried out to develop the nodular cast-in-place concrete pile and nodular diaphragm wall. According to the ultrasonic measurement during the construction of piles or wall and the investigation of pile shape or wall shape after the load tests, the nodular cast-inplace concrete pile and nodular diaphragm wall were constructed as designed. As a result of load tests, the nodular cast-in-place concrete pile and nodular diaphragm wall have large tension and compression resistance. The tension resistance at the nodular part and under-reamed part shows a large value.