Papers by Author: Wei Huang

Abstract: A numerical calculation model of the dynamic response of a tall building -base- foundation system was built. In the modeling, the beams, columns and stakes was described by the BEAM188, and the floor slab described by the SHELL63. The natural frequency and mode of the vibration of the system were calculated by using ANSYS and the response of the system under both horizontal and vertical seismic action were calculated by using the module, Time-History Seismic Analysis, with the elastic modulus of foundation being set as 20MPa, 20GPa, and 30GPa respectively. The result shows that, the horizontal displacement amplitudes of the system were 0.198m, 0.095m and 0.095m respectively under horizontal seismic action, and were 1.13×10^-5m, 1.4×10^-11m and 1.4×10^-11m respectively under vertical seismic action. So the structures on soft foundation take on stronger capacity of resisting vertical earthquake than that on rigid foundation, and the opposite is the case of resisting horizontal earthquake. The story drifts are respectively 6.2×10^-12m, 2.34×10^-6m and 3.46×10^-6m under horizontal seismic action, and respectively 4.3×10^-12m, 4.85×10^-6m and 4.78×10^-6m under vertical seismic action. The story drifts on soft foundation under both horizontal and vertical earthquake action are much less than that on rigid foundation.

Abstract: Making full use of fly ash (FA) is an important part of sustainable materials development in the word. This paper discussed the carbonation resistance of concrete with 10%, 20% and 25% fly ash replacement ratios(FA%). The process was accelerated in artificial carbonation laboratory by controlling 20% concentration of CO2, 10°C~30°C temperature and 50%~70% relative humidity(RH). The depth of carbonation could be observed by spraying phenolphthalein solution on the fresh broken concrete surface. The test results show that adding fly ash into concrete results in the decrease of cement consumption and calcium hydroxide, so carbonation rate increases. But with the increase of FA% and carbonization time, the drop speed of carbonation rate slower, the differences in the microstructure are detailed. In addition, the carbonation rate increases when the ambient temperature varies from 10°C to 30°C and ambient RH falls from 70% to 50%. It concludes that the 10°C ambient temperature and 70% ambient RH are superior to other environmental conditions for enhanceing concrete carbonation resistance, and mixing 10%~25% FA into concrete have little influence on carbonation resistance of concrete if have adequate curing time.