What are the basic principles for seismic design in concrete?

It is possible to minimize the eco- nomic loses by proper seismic design. In this paper basic principles for seismic design are summarized. There are three basic requirements to be satisfied; (a) strength, (b) ductility and (c) stiffness. In the paper these are briefly discussed.

What is seismic design in construction?

Base Isolation Bearings are used to modify the transmission of the forces from the ground to the building. Base Isolation: This seismic design strategy involves separating the building from the foundation and acts to absorb shock.

What is seismic design theory?

Basic Contains Of Design Theory The theory of PBSD contains three aspects: fortification levels of earthquake, seismic performances of structure, design methods of structure. The essence of PBSD is to control the seismic function of structures under future probable earthquakes.

Is reinforced concrete good for earthquakes?

Reinforced concrete has some characteristics that enhance its ability to resist earthquake forces, and others that are detrimental. Perhaps the greatest advantage of reinforced concrete construction is continuity. If one component fails, the load is transferred to other components and the structure stands.

What are seismic design categories?

What is a Seismic Design Category. If A Seismic Design Category is a classification assigned to a structure based on it’s occupancy category, and the severity of the design earthquake ground motion.

What are the objectives of seismic design?

The basic objective is life safety for the design level ground shaking. There are methods within the current model building codes and the new International Building Code (IBC) to increase the detailing and/or seismic design force requirements, but the resulting level of enhanced performance is not explicitly defined.

What is the purpose of seismic design?

Performance Based Seismic Design (PBSD) is a design concept that is currently being applied in seismic design on a variety of buildings and bridges. Its main goal is to produce structures that will have predictable results in the event of an earthquake.

What is a common damage that occurs with precast concrete buildings during an earthquake?

Precast Concrete vs Concrete Masonry Units Buildings and walls made from these units are more likely to collapse and fall apart due to their low integrity.

What is importance factor for seismic design?

In seismic design, occupancy importance factor (IF) is a multiplier to increase or decrease the design base shear, according to different occupancy categories or the importance class of a building.

Who determines seismic design category?

The USGS calculated the design values using: hazard values computed by the USGS on a national scale and. site-specific procedures for seismic design stipulated in Chapter 21 of the NEHRP Recommended Seismic Provisions and the ASCE/SEI 7 Standard.

What are the seismic effect on building?

Earthquake causes shaking of the ground. So a building resting on it will experience motion at its base. From Newton’s First Law of Motion, even though the base of the building moves with the ground, the roof has a tendency to stay in its original position.

Are shear walls good for earthquakes?

Shear walls are a useful building technology that can help transfer earthquake forces. Made of multiple panels, these walls help a building keep its shape during movement. Shear walls are often supported by diagonal cross braces made of steel.

What is reinforced concrete shear wall?

Reinforced concrete shear walls represent a structurally efficient solution to stiffen a building structural system under lateral loads. The main function of a shear wall is to increase the rigidity and strength of the building for lateral resistance.

How is shear wall design calculated?

Where shear wall segments are the same length, simply dividing the total force by the number of segments will provide the force for each one. Unit shear is also easily determined by dividing the total shear force by the sum of resisting segment lengths.

What is seismic designing?

Seismic design is a vital process of structural analysis while designing a building, which is subjected to Earthquake ground motions, such that the facility continues to function and serve its purpose even after an Earthquake.

Why are the building with shear walls preferred in seismic design?

Shear walls provide large strength and stiffness to buildings in the direction of their orientation, which significantly reduces lateral sway of the building and thereby reduces damage to structure and its contents. Since shear walls carry large horizontal earthquake forces, the overturning effects on them are large.

How thick should shear walls be?

8 inches
Minimum nominal thickness of masonry shear walls shall be 8 inches (203 mm). Exception: Shear walls of one-story buildings are permitted to be a minimum nominal thickness of 6 inches (152 mm).

What is the maximum spacing for shear wall reinforcement?

2.1 Shear wall reinforcement requirements. The maximum spacing of vertical and horizontal reinforcement shall be the smaller of one-third the length of the shear wall, one-third the height of the shear wall, or 48 inches (1219 mm).

Why are buildings with shear walls preferred in seismic regions?

Is code for design of shear wall?

Shear walls are very suitable for resisting earthquake induced lateral forces in multistoreyed building systems. They can be made to behave in a ductile manner by adopting proper detailing techniques. IS:456-1978 and IS:4326-1976 do not give specifications for them. Hence, provisions are proposed for the same.

What is the minimum width of a shear wall?

1.1 Shear Wall Thickness. Minimum nominal thickness of masonry shear walls shall be 8 inches (203 mm). Exception: Shear walls of one-story buildings are permitted to be a minimum nominal thickness of 6 inches (152 mm).

What are the four types of seismic zones?

Based on the past seismic history, Bureau of Indian Standards grouped the country into four seismic zones namely Zone-II, Zone-III, Zone-IV and Zone-V. Of all these four zones, Zone-V is the most seismic active region whereas Zone-II is the least.

What is SS and S1 in seismic design?

Ss: Spectral acceleration parameter at short periods corresponding to the mapped maximum considered earthquake. S1: Spectral acceleration parameter at a period of 1 sec corresponding to the mapped maximum considered earthquake.

What is shear wall design?

A shear wall is a general term for a wall that is designed and constructed to resist racking from forces such as wind using masonry, concrete, cold-formed steel, or wood framing. Shear walls significantly reduce the sway of a structure to reduce damage to the structure and its contents.

What is the advantage of shear wall?

Advantages of Shear Wall These walls provide large strength and stiffness in the direction of orientation. Considerably reduces the lateral sway. They are easy in construction and implementation. It is efficient in terms of construction cost and effectiveness in minimizing earthquake damage.

What are the general requirements of shear walls?

1.1. 3 Shear walls shall be provided with reinforcement in the longitudinal and transverse directions in the plane of the wall. The minimum reinforcement ratio shall be 0.0025 of the gross area in each direction. This reinforcement shall be distributed uniformly across the cross section of the wall.

Which shear walls has proved to provide stronger during seismic resistance?

Sheet steel and steel-backed shear panels in the place of structural plywood in shear walls has proved to provide stronger seismic resistance.