In designing a bolted joint, it is important to examine the sealing performance and to estimate the load factor, that is the ratio of an additional axial bolt force to a load. In order to improve the sealing performance raised faces of the interface have been used. But these interfaces in bolted joints have been designed empirically and the theoretical grounds are not made clear. In the present paper, in the case of T-shaped flanges with raised faces the sealing performance (clamping effect) is analyzed by a two-dimensional theory of elasticity and the point matching method. Then, the load factor is analyzed. Moreover, with the application of the load a bending moment is created in bolts and the stress is added due to this bending moment. The bending moment in the bolt is also analyzed. In order to verify these analysis experiments were carried out to measure the load factor and the maximum bolt stress. The analytical results are in a fairly good agreement with the experimental ones.