| 摘要 |
<p>The roof-ceiling construction comprises a wide and thin concrete plate (1) and a two-part upper steel construction (2), interconnected by means of vertical elements (3). The construction is twice prestressed by two independent methods. The concrete plate (1) is centrally prestressed in the mould (86) and after the plate (1) concrete has hardened, the upper steel construction (2) is prestressed by pushing apart, at the midspan, the steel separated halves (2) which are then connected. Prestressing of the concrete plate (1) is applied to eliminate or reduce cracks in its concrete while prestressing of the upper construction by pushing apart the steel halves (2) is used to control the deflections.</p> |
