tailieunhanh - Lifetime-Oriented Structural Design Concepts- P24

Lifetime-Oriented Structural Design Concepts- P24: At the beginning of 1996, the Cooperative Research Center SFB 398 financially supported by the German Science Foundation (DFG) was started at Ruhr-University Bochum (RUB). A scientists group representing the fields of structural engineering, structural mechanics, soil mechanics, material science, and numerical mathematics introduced a research program on “lifetimeoriented design concepts on the basis of damage and deterioration aspects”. | 648 4 Methodological Implementation Fig. . FE calculations with stochastically fluctuating fields of the initial void ratio a dimensions and an example of a field e x b differential settlement due to cyclic loading as a function of the differential settlement due to static loading different fields e x see an example in Figure were tested. Let sl and sr be the settlements of the left and the right foundation respectively Figure . The differential settlement As sr was divided by the mean value s sl sr 2. The ratio As s stat due to static loading up to aav was compared to the ratio As s cyc describing the additional differential settlement accumulated during the subsequent 105 cycles. Independently of the correlation length the differential settlement As s cyc resulting from cyclic loading was observed to be approximately three times larger than As s Btat caused by static loading Figure . This finding can be attributed to the fact that the settlement due to monotonic loading is proportional to the load while the accumulation rate under cyclic loading is proportional to the square of the strain amplitude . approximately proportional to the square of the load. Therefore a cyclic loading has a smaller range of influence than a monotonic loading and inhomogeneities of the field e x near the foundations have a larger effect . the differential settlements are larger due to averaging over a smaller region . Keßler 428 used the high-cycle model to simulate a vibratory compaction in a certain depth Figure the pulling-out of the vibrator was not modelled yet . The initial densitiy and the frequency were varied. In that case the implicit steps of the calculation were performed dynamically. Canbolat 168 determined the settlements of the abutment of a bridge Hunxer Brucke under 53 years of traffic loading. The geometry of the problem and the FE mesh are given in Figure . The profile of void ratio with depth was chosen in accordance with