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Today, environmental health needs more attention than in the past. Objects consisting of plastic materials such as bottles take many years to decompose. Therefore, in the recent years, a lot of research has been done to reuse them and one of which is use in the concrete mixes. In previous research, very low percentages of these materials (between 0.5% and 1.5%) has been used as fine aggregate substitutes in the concrete and evaluations have more focused on the flexural strength. In this research, Polyethylene terephthalate (PET) as a substitute for sand and Polypropylene fibers (PP) as an additive material are used in the concrete mixes. 14 concrete beams in both reinforced and unreinforced states have been evaluated. The replacement percentage of the PET is 10, 30 and 60% and additive percentage of the PP is 0.5, 1.5 and 3% of the total weight of concrete. The dimensions of the beams have been chosen in such a way to categorized in the deep beams. So, rectangular cross-section has been considered (width = 100mm and height = 400mm). Shear strength and ductility are two important parameters that have been evaluated in this research.

Earthquake forces have always been considered as a threat to the structures. One of the most effective ways to have structures with minimal damage and improve their resilience is prevent transmission of earthquake forces to the superstructures. For this purpose, the base isolation method can be implemented. Common types of base isolators are elastomeric rubber bearing and lead rubber bearing. Elastomeric rubber bearing is consisting rubber layers and intermediate steel plates that are produced by vulcanization process and lead rubber bearing (LRB) is similar to the elastomeric rubber bearing but a lead core is located in the center. In this study, shear behavior and vertical stiffness of LRBs are evaluated with the finite element approach. Validation analysis was performed which indicated the accuracy of modeling and then two full scale circle LRBs were selected from Bridgestone corporation with 1000 and 600mm diameters. The main purpose of this paper is evaluating the effect of lead core size, number and location on the shear behavior and vertical stiffness of lead rubber bearings.