Slot Cutting of Concrete Dams: Field Observations and Complementary Experimental Studies
P. Caron, P. Leger, R. Tinawi, and M. Veilleux
Appears on pages(s):
alkali-aggregate reaction; concrete; stress.
Expansion joints have been introduced using diamond wire saws in several existing concrete gravity dams to control deformations and release accumulated compressive stresses due to concrete swelling induced by alkali-aggregate reaction (AAR). Slot cuts have also been used to reduce the detrimental effects of cyclic seasonal thermal loading of dams located in northern regions. It was found, however, that it is difficult to estimate in advance the elastic rebound and long-term closure of slot walls. This paper reports field observations from cuts in three gravity dams. A complementary experimental study on four 1.5 m-long compressed concrete specimens is then presented. Measurements of elastic rebounds and long-term responses are compared with elastic and viscoelastic finite element analyses. The laboratory tests have shown that it is difficult to accurately model the long-term slot closure response, even in a controlled environment where differences from experimental measurements and numerical analyses ranging from 10 to 30% have been observed. This could be mainly attributed to sensitivity to the creep law adopted.