In order to test the micro-vibration control ability of the mass concrete slab in the Beijing High Energy Photo Source,evaluation of the micro-vibration control ability of the mass concrete slab are conducted through two short-period tests and a 24 h long-period monitoring.Test results indicate that:most of the displacement root mean square values distribute between 10 nm and 50 nm in the two short-period tests,and most of the displacement root mean square values distribute below 20 nm in the 24 h long-period monitoring.The mass concrete slab can provide good micro vibration control performance over 10 Hz for the micro vibration in the vertical direction,and over 5 Hz for the micro vibration in the horizontal directions.Through casting the mass concrete slab,the micro vibration level in the vertical direction can be reduced by 24%,the micro vibration level in the horizontal direction can be reduced by 34%.The control ability of the slab to the horizontal micro-vibration is slightly better than that of vertical micro-vibration.Moreover,simplified two-dimensional finite element models are established to discuss the influence of changing the concrete layer's density,stiffness and thickness on the slab's micro-vibration control ability.The simulation results indicate that the increasing thickness of reinforced concrete layer or density of the plain concrete layer has no influence on the micro-vibration control ability of slab in the vertical direction,but has adverse effect on that in the horizontal direction.
关键词
精密科学设施/现场测试/大体积混凝土底板/微振动控制/位移有效值/二维有限元模型
Key words
scientific facilities with high precision/field test/mass concrete slab/micro vibration control/root mean square value of displacement/two-dimensional finite element model
维普
万方数据