Importance of RCC Bands in Load Bearing Structure (Masonry Building)
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RCC Bands in load bearing structure (Masonry Building) are reinforced concrete runner provided in the walls to tie them together and to impart horizontal bending strength in them.
RCC bands or reinforced concrete runner are the important horizontal member of load bearing structure which resists forces and ties wall together. They integrate masonry wall into the stronger unit. RCC bands in load bearing structure are also known as horizontal seismic bands. The dimension of the band and the inside reinforcement bars depends upon the length of the wall between the perpendicular cross walls. There are five types of band namely gable band, roof band, lintel band, sill band, and plinth band, named after their location in the building.
A gable band is a horizontal member which is placed at the top of the ridge of the sloping slab to support the ends of the rafters and transferring loads to posts or gable end walls.
A roof band is a load bearing member of a roof at roof level. Sometimes roof band is not required because the roof slab of load bearing wall masonry also plays the role of a band. Roof beams are generally provided in the building with flat timber or CGI sheet roof.
A lintel band is a horizontal member which is placed at the top of the opening like door and window to support the portion of the unsupported wall above it continuously throughout the length of wall. It is the most important band.
A sill band is a horizontal member which is place at the bottom of the opening to support the load of the window frame. It is discontinued at the door opening.
A plinth band is a horizontal member which is positioned at the plinth level to tie the wall at plinth level.
Also Read: What is a Load Bearing Structural System?
The Function of RCC Bands in Load Bearing Structure (Masonry Building):
- The lintel band ties all the masonry walls together and create a support for adjoining masonry walls loaded along the weak direction from walls loaded in the strong direction.
- They also reduce the unsupported height of the walls, hence improves the stability of masonry walls in the weak direction.
- Lintel band also provides support to chhajja, and sill band support the load of the window frame.
- During an earthquake, bands sustain the shaking and hence minimize damage to load-bearing masonry building.
- They provide ductility and crack proof masonry building, as masonry buildings are as such brittle structure.
Horizontal seismic RCC bands in load bearing structure (Masonry Building) are provided to improve their performance. Even if horizontal bands are provided, masonry buildings are weakened by the openings in their walls hence it is advisable to provide vertical reinforcement at side or corner of opening for better performance of the building.