N°199.1990. Evaluation of the Time Dependent Behavior of Concrete.

The models for the prediction of ti me dependent deformati ons of concrete gi ven in the CEB-FIP Model Code 1978 were controversial already while they were developed . As a consequence , CEB decided in 1980 to establish a General Task Group 9 ( GTG 9)  "Evaluation of the time dependent behav­ior of concrete ".  It had the mission to evaluate existing prediction 

models for the time dependent behavior of concrete and to develop improved or new models if necessary. 

GTG 9 started its work in September 1980. From the onset of the work , it proved to be rather difficult to reach an agreement on the most suit­able code type prediction models. During the last meeting of GTG 9 in July 1987 , the members finally agreed on prediction mode s, which are now included in the draft of the CEB-FIP Model Code 1990 as well as in EN V EC 2. 

I would like to thank all the members of the task group and in par­ticular, the secretary of GTG 9 Dr. H.S. Müller, for their numerous contributions during the lengthy and difficult work of GTG 9.

Karlsruhe , June 1990 

H.K. Hilsdorf 

( Reporter of CEB GTG 9