Where is helical reinforcement used?

The peeling off of concrete outside helical reinforcement provides a warning signal before the sudden failure of columns. In addition, it can take up a higher working load than normal link reinforcement. Hence helical reinforcement is adopted in the design of marine piles in government piers.

Why helical reinforcement is provided?

Test results indicate that the use of helical reinforcement provides enhanced load carrying capacity and a lower deflection proving to be more ductile, clearly indicating the advantage in carrying horizontal loads.

Why helical reinforcement is provided in preference to lateral ties in circular RCC columns?

The circular columns with helical reinforcement have greater ductility or toughness when loaded concentrically or with small eccentricity. So it should be noted that since the helically reinforced columns are very ductile as compared to columns with lateral ties, they are more desirable in highly seismic zone.

How reinforcement is provided in column?

Reinforcement Details In Columns Generally, concrete columns consist of square, rectangular or circular cross sectional area. Columns are essentially required with the primary longitudinal reinforcement and lateral ties to avoid buckling of the primary bars.

Why helical ties are preferred over lateral links?

The use of links for column design in Britain is very popular. However, in U.S.A. engineers tend to use helical reinforcement instead of normal links because helical reinforcement has the potential advantage of protecting columns/piles against seismic loads.

What is spiral reinforcement?

The reinforcement which is used in the spiral column is also known as helical reinforcement or spiral reinforcement. The Spiral reinforcement helps to support in the transverse direction. In the case of spiral column, the lateral expansion of the concrete is restrained by the spiral.

Why column is provided?

Why we provide Columns? Primarily, Columns carry Axial Loads and therefore are designed for compression. Other loads from snow, wind or other horizontal forces can cause bending in the columns. Columns then need to be designed for Axial Load and Bending.

Why stirrups are provided?

Stirrups are provided to hold the main reinforcement rebars [1] together in an RCC structure. Stirrups are placed at proper intervals to beams and columns to prevent them from buckling. Also, they protect RCC structures from collapsing during seismic activities (earthquakes).

Where do we provide reinforcement in RCC?

The reinforcement is usually, though not necessarily, steel bars (rebar) and is usually embedded passively in the concrete before the concrete sets.

What are the uses of helical reinforcement?

The helical reinforcement can also be used as spiral reinforcement. Helical bars are mainly recommended for seismic design. Under the action of seismic loads, the concrete that is attached to the helical reinforcement is initially peeled off. This helps to provide a warning sign about the structural condition of the column.

What is the difference between lateral ties and helical reinforcement?

Compared with lateral ties, the helical reinforcement provides more ductility and flexibility to the column constructed. They also provide more efficiency to support the longitudinal reinforcement. The buckling resistance of the column structure is improved by the use of helical reinforcement.

How much does helical reinforcement increase column load carrying capacity?

Load Carrying capacity of column is increased by 5\% percent when helical reinforcement is provided as a transverse reinforcement 7. Maximum compressive strain in concrete in axial compression is taken to be 0.002

What is the minimum diameter of longitudinal reinforcement in column?

(iii) A column having helical binders must have at least six bars of longitudinal reinforcement within the helical reinforcement. (iv) The minimum diameter of the longitudinal bars shall not be less than 12 mm and the maximum diameter should preferably not exceed 50 mm.