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原文传递 DETERMINATION OF RESILIENT MODULUS OF SUBGRADES USING BENDER ELEMENTS.

题名：	DETERMINATION OF RESILIENT MODULUS OF SUBGRADES USING BENDER ELEMENTS.
作者：	Baig-S; Nazarian-S
关键词：	MODULUS-OF-RESILIENCE; SUBGRADES-; RAPID-METHODS; BENDER-ELEMENTS; TIME-SAVING-METHODS; COST-EFFECTIVENESS
摘要：	Resilient moduli of subgrades are becoming important input parameters in mechanistic pavement design. As such, test methodologies have been introduced by many highway agencies to estimate this parameter. These tests require several hours to perform. Therefore, only a small number of specimens can be tested for a given project. An alternative for rapidly determining the resilient modulus of subgrade soils--bender elements--is presented. Bender elements are thin sheets of piezo-ceramic material which are inserted in a specimen. When subjected to appropriate electric current, a bender element bends and couples seismic energy to the specimen. A bender element can also be used to detect the coupled energy since it converts movement to voltage. For convenience, the end caps of a regular static triaxial test set-up can be retrofitted with a set of transmitting and receiving bender elements. The data reduction, which consists of determining the arrival time of the seismic energy, is simple and can be carried out during the test. The limitation of the device is that the deviatoric stress cannot be varied and as such moduli at low strain levels are measured. Therefore, this method can be utilized parallel to resilient modulus tests when a large number of specimens of similar subgrades must be tested. Based on tests on over 30 different specimens, the bender elements can feasibly provide resilient moduli of subgrade materials at a fraction of the time and at significantly lower investment in initial equipment costs. The bender element tests can be a complement to the resilient modulus test systems.
总页数：	Transportation Research Record. 1995. (1504) pp79-86 (7 Fig., 2 Tab., 12 Ref.)
报告类型：	科技报告