Flexural behaviour of prestressed continuous beams

This paper describes the behaviour of six two-span pre-stressed composite beams, particularly the moment-rotation relationship of the section over the inner support. The testing technique used for this investigation was also improved relative to previous research on continuous beams. In previous research work, beams were generally constructed in one piece and transported to the test rigs, and then placed on the supports. Great care was needed when levelling the supports, because small deviations from the correct position could introduce large values for unwanted moments corresponding to support settlements. Ideally, at least one support required a device to measure forces, and a threaded device should also have been provided to adjust the height of the support as the test progressed. The adjustment was needed because the measuring device, placed between the beam and the fixed support, needed some flexibility in order to give reliable readings for low levels of loading (for instance, self-weight alone). Th...