Recycled rubber-fiber reinforced elastomeric isolators for seismic protection in developing countries

Numerous earthquakes in the past often caused severe damages to infrastructures and loss of life. The conditions are becoming worse since many high-seismic zones are located in developing countries such as Indonesia, where a huge number of buildings are not designed properly and do not have adequate seismic protections. In many cases of earthquake events, low class housing experienced severe damages, causing many casualties. These facts justify the importance of conceiving a low cost seismic protection system for low-class housing, generally applicable in all those developing countries subjected to strong earthquakes. Poor reinforced concrete and masonry buildings that are susceptible to shear loads are commonly found in developing countries, particularly in rural areas. Indonesian non-engineered construction mostly consists of masonry structures confined or unconfined. It is therefore the preferred material in the countryside, which typically consists of clay bricks bonded by mortar joints. Without resisting moment frames, masonry can withstand seismic loads only thanks to the in-plane shear and flexural strength of piers and spandrels, but unfortunately, conventional brick masonry exhibits poor tensile strength, so its capacity to carry horizontal loads is considerably lower than standard reinforced concrete and steel frames. In general, in order to reduce the damaging effects on the building due to earthquakes, some techniques commonly used are; (a) increase the seismic-resistant capacity of the structure (b) involve bracing system (c) use of added damping system and (d) reduce the seismic demands on the structure by incorporating the base isolation system. The seismic base isolation is considered as the efficient seismic protection system. Generally speaking, the base isolators can be classified as frictional and elastomeric isolators. Some types of elastomeric base isolators have been developed by researchers around the world in the last three decades, e.g imposing leads and high damping rubbers. Since the cost of commercial elastomeric isolators is relatively expensive due to the need for steel reinforcement and thick steel plate supports, and they are not so suitable for common building such as housing in developing countries, scientific works in the field of low-cost elastomeric devices have been conducted in the last years. Fiber reinforced elastomeric isolator (FREI) are nowadays considered as a promising device because it costs significantly less thanks to the absence of steel reinforcements. This PhD thesis presents a series of experimentations and comprehensive numerical modeling on fiber reinforced elastomeric isolators (FREIs) mainly made from recycled rubber from industrial waste, aiming to drop down the cost of the isolator device. Several technical detailing are proposed so that the isolation system works effectively for the isolation of low resistant buildings such as masonry housing. The proposed FREI system is mainly applied in unbonded condition to improve the deformability of the isolation device. The study presents several promising performances of the proposed isolation system with favorable production cost.