The preliminary design cost of the Bird's Nest Project reached 3.89 billion yuan, and the steel consumption was 1.36 million tons. When the project started in February last year, the determined cost did not exceed 3.5 billion yuan. At the same time, by optimizing the design, the planned steel consumption is reduced to 53,000 tons. After removing the sliding roof this time, the steel consumption will be further reduced to about 40 thousand tons, and the project investment will also be greatly reduced.

Dong Cong told reporters that the total investment of the Bird's Nest project in the future will probably be controlled within 3 billion yuan. Although the slender bird's nest removes the sliding roof, it will not fundamentally change the appearance and style of the whole building. After the bird's nest is optimized, the biggest change is that it will become more economical and practical. Reporter Liu Yichen also interviewed BOCOG Executive Committee member Wei Jizhong.

In a crowded workshop of the Civil Engineering Department of Tsinghua University, the staff of the research group are re-optimizing the design of the Bird's Nest project. Dong Cong, a professor of civil engineering at Tsinghua University, is the leader of the research team. He told reporters that the original Bird's Nest scheme did have security risks, and the hidden dangers were mainly concentrated on the sliding roof.

Dong Cong told reporters that at present, stadiums with sliding roofs in the world, such as Sky Stadium in Canada, all have sliding roofs on the side walls, but the Bird's Nest puts the sliding roofs on the fixed roofs, because the bearing capacity of the fixed roofs is far less than that of the walls, which increases the possibility of accidents. Dong Cong also specially showed the reporter an experimental effect diagram made by the research group. Facts have proved that the stability of the roof does have security problems.

After four academicians, including Qian Zhou of China Academy of Engineering, reported the problems existing in Olympic events such as the Bird's Nest to the leaders of the State Council, Beijing has clearly made major adjustments to the design scheme of the Bird's Nest. The sliding roof of the original scheme will be cancelled and the opening at the top of the Bird's Nest will be enlarged.

Dong Cong's research group was established by Beijing Science and Technology Commission in March 2002, and their research results will be transferred to the final construction party through Beijing Science and Technology Commission. Now the optimization design of the Bird's Nest without the sliding roof has basically ended, which is the effect diagram of the redesign. It can be seen that the top of the new scheme becomes oval after removing the sliding skylight.