Evaluation of unbonded Strip-STRP bearing based on current design guidelines

<p>The scrap tire rubber pad (STRP) made of natural or synthetic rubber offers substantial vertical stiffness and lateral flexibility, which are suitable properties for seismic isolator application. If a stacked STRP is used as an unbonded seismic isolator, the in-service stress-strain and displacement demand when rollover deformation is allowed can be different from that without considering the rollover. Although design guidelines are currently available for bonded type bearings, there are no established criteria for the unbonded bearings. To investigate the performance and stress-strain demand of unbonded strip-STRP isolators, finite element analysis (FEA) is performed to compare the analytical result with the existing design guidelines. The stress-strain demand of the strip-STRP isolators is substantially influenced by the <i>l/w </i>ratio, and it is found that the in-plane stresses are the key parameters in the determination of the allowable displacement and the effective length. The analysis shows that an STRP isolator carrying a vertical load of 5.0 MPa can efficiently be utilized up to 230% shear deformation.</p>

Freeze-Thaw Resistance of Fine-Grained Soils Stabilized with Waste Material Mixtures

This paper evaluates the use of waste material mixtures including marble dust and scrap tire rubber the stabilization of fine-grained soils in order to remove the effects of freeze-thaw cycles. In this study, a fine-grained soil material was stabilized by using waste material mixtures. Natural and stabilized fine-grained soil samples were subjected to freeze-thaw cycles under different curing periods. After the freeze-thaw cycles, compressive strength tests were performed to investigate effects of waste material mixtures on the freeze-thaw resistance of fine-grained soil samples. The experimental results showed that the samples of fine-grained soil stabilized with waste material mixtures have high freeze-thaw durability as compared to unstabilized fine-grained soil samples. Consequently, we conclude that waste material mixtures including marble dust and scrap tire rubber, can be successfully used as an additive material to enhance the freeze-thaw durability of fine-grained soils for soil stabilization in the geotechnical applications.

Freeze-Thaw Resistance of Fine-Grained Soils Stabilized with Waste Material Mixtures

This paper evaluates the use of waste material mixtures including marble dust and scrap tire rubber the stabilization of fine-grained soils in order to remove the effects of freeze-thaw cycles. In this study, a fine-grained soil material was stabilized by using waste material mixtures. Natural and stabilized fine-grained soil samples were subjected to freeze-thaw cycles under different curing periods. After the freeze-thaw cycles, compressive strength tests were performed to investigate effects of waste material mixtures on the freeze-thaw resistance of fine-grained soil samples. The experimental results showed that the samples of fine-grained soil stabilized with waste material mixtures have high freeze-thaw durability as compared to unstabilized fine-grained soil samples. Consequently, we conclude that waste material mixtures including marble dust and scrap tire rubber, can be successfully used as an additive material to enhance the freeze-thaw durability of fine-grained soils for soil stabilization in the geotechnical applications.