| 摘要 |
<p>Prestressing cables pass through concrete structures (9) in e.g. high-density polyethylene grout-filled guide sleeves (35), typically following undulating routes. Direction changes are negotiated in curved steel deviation tubes (16). At high points, air, water, etc. are bled off through a short vent channel (41) formed, during duct extrusion, between the upper sleeve wall and a curved longitudinal partition cutting off a relatively small proportion of the cross-section. Optionally, the curved partition is inserted in an excision in the sleeve wall, the excised section being then replaced and sealed. Optionally, a separate tube is used. Perforations (25) extending over the summit zone (L1,L2) admit the unwanted fluids. After bleeding, the discharge point (44) is sealed, e.g. by a screw cap.</p> |
