Test Research And Numerical Simulation Of Mechanical Properties Of Plate Type Elastomeric Pad Bearings

At present plate type elastomeric pad bearings have been widely used in bridge engineering, which can transmit the permanent load and variable load to the piers and simultaneously meet the displacement and rotation required by the bridge and the free deformation caused by variable load, temperature changes, concrete contraction, creep and so on, so that the actual situation of force from top to bottom structure comply with the static-type structure. However, during the course of use, the plate type elastomeric pad bearings will appear some anomalies, such as, collapse, cracking and so on, which will cause the bearings failure. The main reason resulting these anomalies is that the mechanical properties of plate type elastomeric pad bearings doesn't satisfy its design requirement.In this paper, test research have been performed on the two important mechanical properties indicator compressive modulus of elasticity and shear modulus. Numerical simulation has been performed on the base of results of test under the situation uniform and uneven thickness of elastomer layer, which analyze internal stress distribution of the elastomeric bearing, as follows:(1) The traditional test methods of compressive modulus of elasticity test are rather cumbersome and take up experimentalists' lots of time. This paper has improved the traditional test methods of compressive modulus of elasticity test, which has collected the holding-load time together to concentrate on holding load. The tests have been performed on different types of bearings, which results show that the results of the improved test method conform to the error range regulated by the standard and can effectively save time for the experimentalists, also eliminate the accumulative error.(2) The shear modulus of elasticity test need the horizontal and vertical imposing load organ to work simultaneously to complete this test. The whole test equipment cost very much, especially the horizontal imposing load organ is more challenging. This paper has developed the shear modulus of elasticity test equipment on the base of existing apparatuses in the laboratory by self and carried out the shear modulus of elasticity test using the above set of equipment. The test results show that the set of test equipment can meet the test standard requirement, which have made preliminary results as an exploratory research work. (3) The numerical simulations have been performed on the elastomeric bearings on the base of the results of the compressive modulus of elasticity test under the two situations uniform and uneven elastomer layer. The FEA model of elastomeric bearing has been proved right through comparing the analysis results with the test results and theoretic formulae. It can be seen from the stress analysis results that the shear stress inside the bearings affect greatly the function of the bearing and the shear stress are inversely proportional to the shape factor of the bearings. It is proposed that the shape factor and the elastomer layer thickness should be solely formulated as an important test indicator. In addition, the analysis results also provide the design and application of the bearings with reference and recommendation.