Shear walls

Selection of appropriate structural system for a given building is important for its safety and economy.It is an important decision that is taken by the structural engineer.For multi-storied buildings, where horizontal loads of great importance, frames with shear walls are provided to resist both vertical and horizontal loads.

Classification of earth quake Slight: Magnitude up to 4.9 on the Richter Scale Moderate: Magnitude 5.0 to 6.9 Great: Magnitude 7.0 to 7.9 Very Great: Magnitude 8.0 and above

Dual systems:Building with dual system consists of shear walls (or braced frames) and moment resisting frames such that,The two systems are designed to resist the total design lateral force in proportion to their lateral stiffness considering the interaction of the dual system at all floor levels andThe moment resisting frames are designed to independently resist at least 25 percent of the design base shear.

SHEAR WALLS:

Reinforced concrete (RC) buildings often have vertical plate-like RC walls called SHEAR WALLS in addition to slabs, beams and columns. These walls generally start at foundation level and are continuous throughout the building height. Their thickness can be as low as 150mm, or as high as 400mm in high rise buildings. Shear walls are usually provided along both length and width of buildings

Reinforced concrete shear walls

Shear walls must be symmetrical plan

Different geometric shapes are used

Reinforcement Bars in RC Wall:Steel reinforcing bars are to be provided in walls in regularly spaced vertical and horizontal grids.The vertical and horizontal reinforcement in the wall can be placed in one or two parallel layers called curtains. Horizontal reinforcement needs to be anchored at the ends of walls.This vertical reinforcement should be distributed uniformly across the wall cross-section.

Main reinforcement in shear walls

Moment resistant frames:A space frame with moment resisting joints and strengthening by shear walls to assist in carrying horizontal loads. The moment-resisting frame must be capable of resisting at least 25 percent of the base shear.Moment-resisting frames carry lateral loads primarily by flexure in the members and joints.

TYPES OF BRACINGS

There are two types of bracing systems,Concentric Bracing System and Eccentric Bracing System.

PROPOSED PROJECT WORK: The project includes a study on analysis and design of building with moment resistant frames and dual system in high seismic zones. The design and analysis is with both manual and software, so that the result is compared in all the parameters like Modeling the frame, assigning the loads.