基于海水干湿循环的天然橡胶支座剪应变 相关性试验研究

Seawater wet-dry cycles test on the natural rubber bearing (LNR) with 220 mm diameter was carried out to investigate the shear-strain dependency of LNR, the shear-strain dependency of LNR was tested on a regular basis during the test for as long as 60 days. And the trend of shear-strain dependency and its trend with seawater wet-dry cycles time were obtained by comparing and analysing the test results. The trend of horizontal stiffness of LNR with test time and change law of the value of K_ht(γ)/K_h0(100%) with seawater wet-dry cycles time were also gained, which can provide theoretical support for the research on the influence of seawater wet-dry cycles or other marine environment on the property of LNR and the design about sea-crossing bridge and other offshore traffic engineering, etc. The results of the test indicated that: Under the same seawater wet-dry cycles test time, the variation rang of horizontal stiffness of LNR with shear-atrain from 50% to 150% is about 11%, which illustrates the horizontal stiffness of LNR has a good stability; Under the same shear-strain, horizontal stiffness of LNR increases with increasing seawater wet-dry cycles time. After 60 days test, the increase amplitudes of horizontal stiffness of LNR with shear-strain from 50% to 150% are 19.67%, 20.89%, 22.60%, 23.73% and 24.95% respectively, which illustrates the horizontal stiffness of LNR is vulnerable to the influence of seawater wet-dry cycles. Also, the ratio of K_ht(γ)/K_h0(100%) increases with increasing seawater wet-dry cycles time and it decreases with the increasing shear strain, which shows that both the seawater wet-dry cycles and the shear-strain can affect the level of K_ht(γ)/K_h0(100%).