Taking the hollow reinforced concrete hollow slab floor with GBF thin-wall pipes used in Chongqing Business College as an example, this article introduced the buoyancy calculation method of GBF thin-wall pipes in concrete and the measures used to control the adversary effect caused by buoyancy, which can provide guidance for similar projects.

According to the study on thecompositions and proportion, producing and the characteristic of the GRC duct and the test of the application to the civilair defence underground engineering, the problem of the GRC duct applied to the civil air defence underground engi-neering that are needed to pay attention to are presented.

This article introduced the construction principle, construction process, construction detailing, and application advantage, as well as the common problems and control points of large diameter GRC precast thin-wall tube hollow flat floor, so as to control the construction quality and improve the development and application of this type of floor system.

Study on soft-contact electromagnetic continuous casting of hollow billet;

5%Pb hollow billet under traveling magnetic field.

Distribution of magnetic field in electromagnetic continuous casting process of Al-alloy hollow billets is studied by way of numerical simulation.