| 摘要 |
<p>A free span arch structure includes transversely spaced elongated flexible sections flexed from a straight configuration without exceeding a yield point to impart a permanent set. Structural sections are lifted by exerting force as by a crane intermediate the ends in a medial portion. An intermediate portion of the pipe is raised by the application of the lifting force while supporting the opposed ends of the pipe on the ground. When the pipe is lifted, the ends restrained and the lifting force removed with the pipe-in a natural state of repose after the application of the load imposed by its own weight, the flexed pipe will assume a parabolic configuration.</p> |
