The gravity resistance structures on rocks (gravity dams

anchors of the suspension bridges

etc.) are born huge horizontal forces. The volume of the structure would change significantly if the coefficient of resistance changes a little for keeping resistance

which will increase the cost of the structure. The direct shearing tests have been completed with the contact surfaces between concrete and light to full weathered granite rocks. The test results show that the cohesion and the friction angles depend on the weathered degree and the roughness of the rocks. The area of the weathered degree and the roughness of the rocks are divided in the field when the pits excavated. The means of the cohesion and the friction angle are obtained by the experiment and the field test. The results are useful for check of the stability of the anchors and as reference of the similar gravity structures.