| 摘要 |
<p>A prestressed truss for constructing bridges is supported at a number of points (1, 2) in order to form two series of truss elements (4a, 4b, 4c, ... 5a) in respect of each span. Each truss element comprises a top chord member (6a) of concrete and a bottom chord member (8a) of concrete, said members being connected together by means of bars (10a, 11a, 12a) forming an N-panel. The vertical bars (10a, 11a) are placed near the ends of the chord members and essentially resist tensile forces. The third bar (12a) resists compressive forces and is upwardly inclined in the case of the first series of truss elements (4a, 4b, ...) and downwardly inclined in the case of the second series of truss elements (5a, ...) located beyond a point M at which the shearing forces under continuous load are substantially zero.</p> |
