| Summary: | 碩士 === 國立臺灣大學 === 土木工程學研究所 === 95 === This multi-axial testing system (MATS) to be installed in the Taiwan National Center for Research on Earthquake Engineering is a 6-degree-of-freedom testing facility. This research designs and analyses the loading frame and the test platen in the MATS. MTS Systems Corporation designs the hydraulic and control system. The MATS can apply vertical, horizontal, lateral loading, and three directions of moment on a specimen. That allows the MATS to test a verity of specimens with realistic loading conditions.
There are two extreme categories of experiments considered in the design of the MATS. One demands capabilities of high vertical force (40MN), low horizontal force (4MN), and large horizontal displacement (1.2m). The other demands capabilities of low or zero vertical force, large horizontal force (8MN), and moderate displacement (0.5m). This research designs and analyses the strength and stiffness demands on the steel platen, demands of the post-tensioned concrete frame, and the steel cross beam. To satisfy these testing requirements, there are a total of thirteen actuators in the MATS. One 30MN pressure balanced actuator and eight hydrostatic actuators (six 5MN (hydrostatic) and two 2MN hold down (pressure balanced)) are used for vertical movement control, and four hydrostatic bearings are used to provide translational and rotational deformation capacities of the platen in the horizontal plane.
To reduce the construction cost, the loading frame is constructed by using post-tensioned reinforced concrete. A 33.6MN post-tension force is to be applied to each column of the MATS. By using SAP2000 FEM model, the deformations and the stresses of platen and cross beam are checked. The maximum deformation of the cross beam is within the 5mm limit while the maximum rotation is within the limit of 0.001 radians. System performance curves are constructed to allow the users to check whether specific loading combinations for the specimen can be applied.
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