What are the Types of members in Prestressed Structures?

PRE-STRESSED STRUCTURE :

Definition :

The prestressed structure is a structure whose overall integrity property, the stability of the structure and its security mainly depends on prestressing.

Important Note :

The international creation of damped permanent stresses within the structure is mainly for the improvement of its performance under various service conditions.

Basic Type of Prestressing are as given below :

1. The precompression is strongly depended on the self-weight of the structure.
2. The pre-tensioning with high strength embedding tendons.
3. Post-tensioning with high strength bonded or unbonded tendon.

Interesting Point :

• Nowadays, the concept of prestressed structure is mostly employed in the design of various buildings.
• The prestressed concrete concept is also used in the underground structure, TV Towers, Power stations, Floating storage and Offshore facilities, nuclear reaction vessels and numerous bridge systems.

Pre-stressed concrete is a form of concrete used in construction. It is substantially prestressed during production, in a manner that strengthens it against tensile forces which will exist when in service. According to the construction methods there are two kinds of prestressed concrete :- - Pre-tensioned concrete - Bonded Post-tensioned concrete - Unbonded Post-tensioned concrete The three types of members in prestressed concrete are as follows:- 1. Neither allowing tension nor crack. 2. Allowing tension within permissible stress but cracking is not allowed. 3. Tension and crack both are allowed but within permissible stress.

There are three types of members in prestressed concrete

TYPE 1 – Tension is not allowed; Cracking is not allowed.

TYPE 2 – Tension is allowed (within permissible stresses) ; Cracking is not allowed.

TYPE 3 – Tension is allowed; Cracking is allowed within permissible stresses.

Type 3 members are the most economical members because they allow cracking and thus use the elastic property of the materials.