pc lecture 1 Flashcards
(28 cards)
Obtained a patent for the manufacture of Portland cement
Aspdin J. in England (1824)
introduced steel wires in concrete to make flowerpots, pipes, arches and slabs.
Monier J. in France (1857)
introduced the concept of tightening steel rods in artificial stone
and concrete arches.
Jackson P.H. of USA (1886)
manufactured concrete slabs and small beams with embedded tensioned steel.
Doehring C.E.W. of Germany (1888)
Recognized the losses due to shrinkage and creep.
Stainer C.R of USA (1908)
Developed a method of winding and pre-tensioning high
tensile steel wires around concrete pipes
Emperger F. of Austria (1923)
Hoop-stressed horizontal reinforcement around walls of concrete
tanks through the use of turnbuckles
Hewett, W.H of USA (1924)
Used high strength unbonded steel rods
Dill, R,H of USA (1925)
Used high tensile steel wires. ultimate strength as high as 1725 MPa, yield stress over 1240 MPa
Eugene Freyssinet of France (1926)
He developed conical wedges for end anchorages of post-tensioning and
developed double-acting jacks.
Eugene Freyssinet of France (1939)
Father of prestressed concrete.
Eugene Freyssinet
Developed the long-line pre-tensioning method.
Hoyer, E. of Germany (1938)
Developed an anchoring system for post-tensioning using
flat wedges.
Magnel, G. of Belgium (1940)
Built numerous prestressed concrete bridges
in western and central Europe.
Guyon, Y. of France
Introduced the concept of partial prestressing.
Abeles, P.W in England
In Europe, the application of prestressing
the concrete bridges became popular during
1940s and 1950s
Very famous in the field of prestressed concrete
Leonhardt F. in Germany, Mikhailor V. in Russia and Lin T.Y in USA
Was being applied in various types of structures like building frames,
parking structures, stadiums, railway sleepers, transmission line poles, water tanks and
several other types of elements.
Prestressed concrete
Example of the use of prestressed concrete
girders.
Pamban Road Bridge, India
Is the application of
an initial load on a structure, to enable it to counteract the stresses arising from
subsequent loads during its service period.
Prestressing
Two such examples of prestressing
- Force-fitting of metal bands on wooden barrels
- Pre-tensioning of the spokes in a bicycle wheel
Concrete’s tensile strength is only
8 to 14 percent of its compressive strength
Prestressing enhances
Bending, shear, torsional capacities of the flexural members
In cylindrical tanks, the hoop tensile
stress can be effectively counteracted by
Circular prestressing
