A single layer reticulated shell affected by several types of initial random imperfections is analyzed using Monte-Carlo reliability technique. The reliability analysis is carried out taking into account the uncertainties in some structural parameters such as applied loads ,steel yield stress and the randomness of the initial imperfections. All proposed types of initial imperfections are practical ones duo to the fact that the theoretical geometry of the shell does not coincide with the actual one. The values of the proposed random variables are assumed to be normally distributed.The Monte-Carlo simulation method is used to generate the set of normally distributed random variables. The limit state functions which are derived especially for the space truss element are presented . A computer program is prepared especially to analyse the reticulated shell according to the proposed technique. Each type of imperfections is investigated separately to clarify its effect on the . reliability measures of both element and system. The statistical properties of the members internal forces are also obtained. Finally, the paper aims at determining the tolerances of the proposed initial imperfections that meet the required reliability level or probability of failure.
(1)Professor of Struc. Engrg., Ain Shams Univ., Cairo,Egypt. (2)Assoc. Professor of Struc. Engrg.,Ain Shams Univ. ,Cairo, Egypt. (3)Assist. Professor of Struc. Engrg.,Benha Higher Institute of Technology,Benha,Egypt. (4)Lecturer Assistant of Struc. Engrg.,Benha Higher Institu-te of Technology,Benha,Egypt. |
