Study On The Topology Optimization Method Of3D RC Components

Such as thick pilecaps and post-tensioned anchorage blocks, they are huge renforced concrete blocks with similar dimensions in three directions of the space, in which the stress of flow transfers in three directions, so the conditions of internal force of the structure is very complicated under specific loads, and the problem belongs to space sress problem rather than the plane sress problem. We can called these structures the three-dimensional renforced concrete stuctures, and of which it is suggested to be more appropriate to apply space stess analysis in the structure design. With the rapid development of urbanization of our country, the rise of tall building structures and long-span bridges is an inevitable trend. Thick pilecap as an important component of the tall building structures, to a certain extent determines the height of tall building structures and the safety degree of upper structures. Post-tensioned prestress is more and more widely applied in the long-span bridges, as part of the post-tensioned prestressed concrete structures, the anchorage block is the only connection between the girder and the prestressed reinforcement, which decides that anchorage block is particularly important. However, the design methods of thick pilecaps and anchorage blocks in current specifications of our country still have some unreasonable points, need to be further improved and perfected, so, in this paper, a new design method applied to the3D RC components such as thick pilecaps and anchorage blocks is studied.Based on the real internal stress distribution, the space STM method is on behalf of the mechanism of true force action and is a more reasonable design method than the plane STM method. Desgners can only correctly and appropriatlely apply the space STM method to structure design on the condition that the space STM which can refect the true internal force is built. From load-path method to elastic stress analysis method, then to topology optimization method, the methods of building STM have been greatly improved, amomg which there are still plenty of discrepancy and disagreement. How to build a reasonable space STM is still a tough problem to be settled in the structure design. The main contents are presented as below:(1) According to the Chinese current relative specifications, bearing capacity calculation and structure reinforcement design are separately conducted on the T-beam anchorage block, box girder anchorage block, thick pilecap with four piles and double-column combined thick pilecap with six piles.(2) With the help of finite element software ANSYS, the optimal topology configurations of the anchorage blocks and thick pilecaps are obtained by using GESO algorithm.(3) Appropriate and reasonable space STMs are separately built according to the optimal topology configurations of anchorage blocks and thick pilecaps; and then in accordance with the STM method in the appendix A of ACI318-08, the bearing capacity calculation and structure reinforcement design of anchorage blocks and thick pilecaps are detailedly conducted. After topology optimization design, the concrete and steel consumption can be reduced compared with the Chinese specification design results.(4) According to the topology optimization calculation and design in the thesis, the STMs built based on the optimal topology configurations using GESO algorithm are verified to be reasonable and effective, and the GESO algorithm can be extended to the topology optimization design of3D RC components.