An Earthquake Resistant Design with used Rubber Tyres
The proposed construction is based on interlocking of pre-cast slotted concrete blocks with the help of low yield strength visco-elastic energy dissipation links.These blocks are cast in concrete and links are prepared by pieces of used rubber laminated by very thin steel plates.
A new block masonry construction technique for earthquake resistant housing is being proposed which is based on energy dissipation through damping. The energy dissipation is provided in the form of effective damping in the structure through the low yield strength visco-elastic link element as well as friction. The construction is based on interlocking of pre-cast slotted concrete blocks with the help of low yield strength visco-elastic energy dissipation links. These blocks are cast in concrete and links are prepared by pieces of used rubber laminated by very thin steel plates. These links not only restrict the movement of each concrete block in all possible directions but also dissipate the energy through yielding under extreme earthquake loading conditions. The load capacity of these links is kept lower than that of the concrete blocks so that under strong earthquake shaking, the energy is dissipated through friction between concrete blocks and the deformation of links takes place without damaging the concrete blocks.
The construction process
The construction of inter-linked block masonry system with viscoelastic energy dissipator links is quite simple and easy to apply in field. The different concrete blocks are prepared in the form of stretchers,corner and half blocks of size 150mmx 230 x 300mm, 150mmx 230 x 380mm, 150mmx 230 x 150mm respectively to form any types (L/C/T/ +) of joints. The weight and volume of one stretcher block replace approximately conventional six bricks of first class. Two slots on the upper and lower horizontal bedding surface and one slot of half thickness on each side of block are provided. Visco-elastic links are prepared by using the used or discarded rubber tyres since it has numerous inherent desirable properties. The used rubber tyres have excellent tear, shear, tensile and fatigue capacity in addition to thermal resistance. These tyres are also reinforced with very thin wires which produce the desirable stiffness and damping that may be helpful
in reducing/ or preventing any residual deformations in the structure or even in block itself. These used/discarded tyres are very low in cost and easily available in the market since it is difficult to re-use them further for any other commercial purpose. These links are prepared by cutting of tyres in specified dimensions and laminated with thin steel plate with the help suitable adhesive under a normal pressure.
Test Parameters
The performance of inter-linked block masonry system is tested under a series of strong simulated earthquake shakes on a 3.5 m x 3.5 m, bi-axial, servo-controlled Shake Table Facility at Department of Earthquake Engineering, Indian Institute of Technology, Roorkee.These tests are performed on a full-scale single story inter-linked block masonry model with visco-elastic link elements. The plan size of the models is 2260mm x 2260mm and height 1800mm with wall thickness of 230mm constructed on a steel base plate which is connected to the shaking platform with bolts. The roof of the model consists of a reinforced concrete slab of a thickness 100 mm. The model is tested under the simulated motion corresponds to the strongest earthquake motion expected in the most severe seismic zone V (effective peak ground acceleration of 0.36 g) as per Indian Seismic Code.
Result
The tested system withstands this severe shaking without any distress and is found to be in a fit state for immediate occupation even after the test. The concept of block masonry with visco-elastic link is successful since the energy is completely released through friction between the blocks and yielding of links at the bottom portion of the model and the top of the model remains intact and not a single block is displaced from its original position.
A new block masonry construction technique for earthquake resistant housing is being proposed which is based on energy dissipation through damping. The energy dissipation is provided in the form of effective damping in the structure through the low yield strength visco-elastic link element as well as friction. The construction is based on interlocking of pre-cast slotted concrete blocks with the help of low yield strength visco-elastic energy dissipation links. These blocks are cast in concrete and links are prepared by pieces of used rubber laminated by very thin steel plates. These links not only restrict the movement of each concrete block in all possible directions but also dissipate the energy through yielding under extreme earthquake loading conditions. The load capacity of these links is kept lower than that of the concrete blocks so that under strong earthquake shaking, the energy is dissipated through friction between concrete blocks and the deformation of links takes place without damaging the concrete blocks.
The construction process
The construction of inter-linked block masonry system with viscoelastic energy dissipator links is quite simple and easy to apply in field. The different concrete blocks are prepared in the form of stretchers,corner and half blocks of size 150mmx 230 x 300mm, 150mmx 230 x 380mm, 150mmx 230 x 150mm respectively to form any types (L/C/T/ +) of joints. The weight and volume of one stretcher block replace approximately conventional six bricks of first class. Two slots on the upper and lower horizontal bedding surface and one slot of half thickness on each side of block are provided. Visco-elastic links are prepared by using the used or discarded rubber tyres since it has numerous inherent desirable properties. The used rubber tyres have excellent tear, shear, tensile and fatigue capacity in addition to thermal resistance. These tyres are also reinforced with very thin wires which produce the desirable stiffness and damping that may be helpful
in reducing/ or preventing any residual deformations in the structure or even in block itself. These used/discarded tyres are very low in cost and easily available in the market since it is difficult to re-use them further for any other commercial purpose. These links are prepared by cutting of tyres in specified dimensions and laminated with thin steel plate with the help suitable adhesive under a normal pressure.
Test Parameters
The performance of inter-linked block masonry system is tested under a series of strong simulated earthquake shakes on a 3.5 m x 3.5 m, bi-axial, servo-controlled Shake Table Facility at Department of Earthquake Engineering, Indian Institute of Technology, Roorkee.These tests are performed on a full-scale single story inter-linked block masonry model with visco-elastic link elements. The plan size of the models is 2260mm x 2260mm and height 1800mm with wall thickness of 230mm constructed on a steel base plate which is connected to the shaking platform with bolts. The roof of the model consists of a reinforced concrete slab of a thickness 100 mm. The model is tested under the simulated motion corresponds to the strongest earthquake motion expected in the most severe seismic zone V (effective peak ground acceleration of 0.36 g) as per Indian Seismic Code.
Result
The tested system withstands this severe shaking without any distress and is found to be in a fit state for immediate occupation even after the test. The concept of block masonry with visco-elastic link is successful since the energy is completely released through friction between the blocks and yielding of links at the bottom portion of the model and the top of the model remains intact and not a single block is displaced from its original position.
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