SOME TESTS ON THE EFFECT OF TIME ON TRANSMISSION LENGTH IN PRE-TENSIONED CONCRETE

摘要

A certain amount of work already published has indicated that the transmission length in pre-tensioned concrete increases very considerably with time. Evans reports a transmission length increase for 0.08 in. diameter high-tensile steel wire from 58 diameters to 125 diameters in 2 1/2 years, with most of the increase taking place in the first month after transfer. A Swiss report also quotes figures showing for 2 and 3 mm diameter an eventual doubling of the transmission length at transfer.nRecent work by the Cement and Concrete Association on 0.2 in. diameter smooth wire indicates no such increase in transmission length, there being little movement, over several months, of the point at which maximum concrete strains were reached in the units tested.