Rotation Of Structure Monitoring Under Seismic Based On MEMS Inclinometer

Earthquake is one of the huge, inevitable natural disaster which the common world facing. Sudden and strong and short duration characters make it cause significant casualties and economic losses. The rotation process of structural components and the foundation of building structural under earthquake is one of the important parameters of impact and characterization of structural damage. Therefore, monitoring the structural rotation under seismic has a significant meaning for better understanding the mechanism of structural damage. However, it is lack of available convenient, reliable and value method of monitoring structural rotation currently. This paper puts forward a monitoring method of structural rotation under seismic based on MEMS inclinometer around the theme. And mainly carry out the following works:1) According to the research of MEMS inclinometer’s internal structure, the analytical solution of dynamic response will be obtained. By assuming structural parameters, definite the roughly relationship between input frequency and the difference percentage. Through the static and dynamic calibration experiments, determined the sensitivity coefficient of the inclinometer and the applicable condition of using inclinometer based on MEMS:For meeting certain engineering measurement error conditions, when external excitation frequency exceeds0.5Hz. it is necessary to correct the output data of inclinometer by a quartic polynomial.2) This paper designs one layer plexiglass frame model, the foundation is connected with springs to achieve the set foundational rotation stiffness. The shake-table sweep experiment make sure the accuracy of the established model, sinusoidal displacement excitation experiment obtain the rotation angular of foundation and the restraint stiffness, El Centro earthquake wave input confirmed the feasibility of monitoring method. This paper establishes the finite element model for the frame model. By established of frame model and division of the grid, displacement load is applied on the bottom of the frame, it is intuitively to get the basis rotation angular and cross moment of column bottom, then calculate the foundation rotational stiffness. By comparison with shake-table data and theoretic value of foundation rotational stiffness, identified the feasibility of the monitoring method and accuracy of the calculation of rotational stiffness.3) This paper designs a reinforced concrete cylinder column model, and takes it in the reciprocating thrust experiment. Three inclinometers are embedded in the column, and carry them to measure the angular of the node plastic hinge rotation. Comparing with displace meter’s output angle to estimate the accuracy of the inclinometer. It turned out that the measurement method is feasible and effectiveness in the real structure.According to a series of laboratory test, it confirms that method of measuring structural rotation by MEMS-based inclinometer is generally accurate and feasible. The different characteristics of the structure will be obtained by using inclinometer combined with other different sensors. It has a certain guiding significance and referential meaning for structural design and improves the overall structure stability and seismic resistance.