Prestressed Concrete - Basic Concepts
Concrete is strong in compression, but weak in tension: its tensile strength varies from 8 to 14 percent of its compressive strength. Due to such a low tensile capacity, flexural cracks develop at early stages of loading. In order to reduce or prevent cracks from developing, a concentric or eccentric force is imposed in the longitudinal direction of the structural element. This force prevents the cracks from developing by eliminating or considerably reducing the tensile stresses at the critical mid span and support sections at service load, thereby raising the bending, shear, and torsional capacities of the sections.
The sections are then able to behave elastically, and almost the full capacity of the concrete in compression can be efficiently utilized across the entire depth of the concrete sections when all loads act on the structure.. Such an imposed longitudinal force is called a prestressing force, i.e., a compressive force that prestresses the sections along the span of the structural element prior to the application of the transverse gravity dead and live loads or transient horizontal live loads.
I have attached presentation on prestressed concrete which includes the following topics in it;
Prestressed Concrete Introduction
Comparison with reinforced concrete
Economics of Prestressed Concrete
Material for Prestressing
Types of prestressing
Loss of prestress
Basic concepts of prestressing
Basic prestressing methods
ACI maximum stress limits
Example calculations
Design of Prestressed member
Prestressed concrete examples
Concrete is strong in compression, but weak in tension: its tensile strength varies from 8 to 14 percent of its compressive strength. Due to such a low tensile capacity, flexural cracks develop at early stages of loading. In order to reduce or prevent cracks from developing, a concentric or eccentric force is imposed in the longitudinal direction of the structural element. This force prevents the cracks from developing by eliminating or considerably reducing the tensile stresses at the critical mid span and support sections at service load, thereby raising the bending, shear, and torsional capacities of the sections.
The sections are then able to behave elastically, and almost the full capacity of the concrete in compression can be efficiently utilized across the entire depth of the concrete sections when all loads act on the structure.. Such an imposed longitudinal force is called a prestressing force, i.e., a compressive force that prestresses the sections along the span of the structural element prior to the application of the transverse gravity dead and live loads or transient horizontal live loads.
I have attached presentation on prestressed concrete which includes the following topics in it;
Prestressed Concrete Introduction
Comparison with reinforced concrete
Economics of Prestressed Concrete
Material for Prestressing
Types of prestressing
Loss of prestress
Basic concepts of prestressing
Basic prestressing methods
ACI maximum stress limits
Example calculations
Design of Prestressed member
Prestressed concrete examples
