| The basis for ensuring the collaboration of steel and concrete to work together is having a good bond between them. If not bond degradation and failure will inevitably lead to the reduction of the mechanical properties of reinforced concrete structures Performance relationship bonded to the bearing capacity, stiffness and crack, research on bonding mechanism, bond strength and bond performance influencing factors of reinforced concrete members and other issues of great significance. Reinforced concrete structures during service, in addition to being static loads, but also may be subject to wind load, seismic load dynamic load effects, such as impact load. Therefore, this article is mainly carried out by means of Reinforced test load at different working conditions and stress state rate of reinforced concrete bonding properties. Therefore, present thesis mainly focuses on the Effect of Loading Rate on Bond Behavior of Reinforcement in Concrete under Different Working Conditions. The main research contents and conclusions are listed as follows:(1) The influence of loading rate on the bond behavior between plain round bars and concrete under lateral pressure was studied through pull-out tests, and calculation models for the effect of the loading rate on the bond slip curves and bond parameters were given. The experimental results showed that the influence of loading rate on bond behavior depending upon the value of lateral pressure. When no lateral pressure is applied, the bond behavior is insensitive to the loading rate. However, for a given lateral pressure, the ultimate and residual bond strengths increase but the slip at the peak bond stress decreases with the increase of the loading rate.(2) The results on the test of lateral compressive stress loading rate on deformed bars showed that, bonding failure and loading rate have a relationship with the amount of lateral stress. When the loading rate is higher and without a lateral stress, internal cracks appear in the concrete and the crack width increases. When lateral stress is applied all ofnf the specimens underwent split failure, the width of the cracks decreased with the increase of the rate of loading.(3) The effect of loading rate on the deformed bar bond behavior under lateral stress was studied using the pull out test. The results of the test showed that for constant bond strength, residual strength and bond stiffness, with the increase of loading rate it showed an increasing trend, but the bond slip value that corresponds to the peak value of the bond stress showed a decreasing trend. The increase in lateral stress and loading rate increase caused the increase in proportion of bond stiffness.(4) Loading rate also has a relationship with deformed bar bond properties after application of high temperature, but this relationship is highly dependent on the amount of temperature applied. When the temperature is higher the rate of loading has more pronounced effect on the bond behavior. With the increase of loading rate, after application of high temperature the bond strength, bond stiffness, and the residual bond strength also increases, but the bond slip that corresponds to the bond stress decreases. When the temperature applied surpasses a certain level, bond slip increases with the rate of loading. |
PDF Full Text Request