The optimum design used FEM analyses and the development of wooden check dam : Part 2,
Failure tests and the performance assessment of cost reduction type all wood type wooden check dam

Tomohiro CHIDA, Takanobu SASAKI, Ryu NODA, Takato INOUE, Toshimasa HARATA and Yasuhiro MIURA

In Akita prefecture in Japan, all wood type wooden dam composed only wood members and lag screws has studied and developed from2001, and it actually have constructed forty in 2011. However, to construct them continuously and to make to diffuse them all over Japan, the cost reduction was required because the costs of them are about two times higher than concrete dam. In previous paper, we proposed the cost reduction method using FEM, and designed the dam where all lag screws on downstream side except the first tier changed round steels as one of optimum design. This dam can decreased the cost 27% and have safety rate 8 for the design load. In this paper, we actually made real]size cost reduction type dam specimen designed previous paper, which called mixed type model in this paper, and conducted horizontal load test. In this test, not round steels but deformed steel bars were used, because the costs of deformed steel bar were far cheep than round steels and deformed steel bars can be obtained briefly at the market. The design method by using FEM was verified by comparing with test results, and the performance of mixed type model was accessed. The test specimen was broken at 84.4 kN by pull]out of lag screw at first stair. These results coincided with the results of FEM very well. Therefore, it was confirmed that the design method using FEM had enough validity and high accuracy and mixed type model specimen had safety rate 8. Additionally, the results of mixed type model specimen compared with the specimen used only lag screw whose test was carried out 2007, it was shown that there is no great difference except failure load.