What is end block zone in prestressed concrete?

The end zone (or end block) of a post-tensioned member is a flared region which is subjected to high stress from the bearing plate next to the anchorage block. Through the end block, pre-stress is transferred from concentrated areas to linearly distributed fiber stresses.

What is reinforcement in prestressed concrete?

Reinforced concrete and prestressed concrete are both reinforced with longitudinal and transverse steel bars, also known as rebar. The main function of the reinforcement is to strengthen concrete when it undergoes tensile stress.

What are the necessary to prevent failure at the end zones?

Explanation: In the transfer zone of pretensioned beams, transverse reinforcements are necessary to prevent the failure of the end zones due to cracking of concrete as a consequence of large transverse tensile stresses, which often exceed the tensile strength of concrete.

What is the end zone reinforcement and stress distribution in end block?

The reinforcement is distributed within a length from 0.1yo to yo from an end of the member. The amount of end zone reinforcement in each direction Ast is: s The parameter represents the fraction of the transverse dimension covered by the bearing plate. The stress in the transverse reinforcement, fs = 0.87fy.

What is bursting tension?

A measure of the magnitude of the prestressing force related to the resultant stress occurring in the structural member at working load. 5. Define Bursting tension. The tensile stress in steel which produces a residual strain of 0.2 percent of the original gauge length on unloading.

Why reinforcement is provided?

Reinforcement for concrete is provided by embedding deformed steel bars or welded wire fabric within freshly made concrete at the time of casting. The purpose of reinforcement is to provide additional strength for concrete where it is needed.

What are the three major types of reinforcement used in prestressing?

Three major types of reinforcement used in prestressing

• (i) Spalling reinforcement. Spalling stresses are established behind the loaded area of anchor blocks and this causes breaking away of surface concrete.
• (ii) Equilibrium reinforcement.
• (iii) Bursting Reinforcement.

What is RCC and PSC?

Prestressed concrete sections are thinner and lighter than RCC sections, since high strength concrete and steel are used prestressed concrete. In prestressed concrete, whole concrete area is effective in resisting loads, unlike RCC where concrete below the neutral axis is neglected.

What is the main advantage of a composite member?

Explanation: The main advantage of composite member is it facilitates the ease of work at the construction site and it is the fast approaching process by utilizing the self supporting precast stems the shuttering can be minimized.