Prestressed Concrete Bridges

PRESTRESSED CONCRETE BRIDGES

Advantage of prestressed concrete bridge deck

•  High-strength concrete and high-tensile steel,    besides    being economical, make for slender sections, which are aesthetically superior.

·        Prestressed concrete bridges can be designed as class I type structures without any tensile stresses under service loads, thus resulting in a crack-free structure.

·        In comparison with steel bridges, prestressed concrete bridges require very littlemaintenance.

·        Prestressed concrete is ideally suited for composite bridge construction in which precast prestressed girders support the cast in situ slab deck. This type of con• struction is very popular since it involves minimum disruption of traffic.

·        Post-tensioned prestressed concrete finds extensive applications in long-span continuous girder bridges of variable cross-section. Not only does it make for sleek. structures, but it also effects considerable saving in the overall cost of construction.

·         In recent years, partially prestressed concrete (type-3 structure) bas been pre•

ferred for bridge construction, because it offers considerable economy in the use of costly high-tensile steel in the girder.

Typical types Of Pre-Tensioned Prestressed Concrete Bridges

PROBLEMS

QUESTIONS AND ANSWERS

1.  what is main advantage of prestressed concrete bridge deck.

•  High-strength concrete and high-tensile steel,    besides    being economical, make for slender sections, which are aesthetically superior.

·        Prestressed concrete bridges can be designed as class I type structures without any tensile stresses under service loads, thus resulting in a crack-free structure.

·        In comparison with steel bridges, prestressed concrete bridges require very littlemaintenance.

·        Prestressed concrete is ideally suited for composite bridge construction in which precast prestressed girders support the cast in situ slab deck. This type of con• struction is very popular since it involves minimum disruption of traffic.

2.Typical types Of Pre-Tensioned Prestressed Concrete Bridges .

a.     Voided slab

b.     Single tee

c.      Box beams

d.     Double tee

e.      Aasho-type girders with slab(U.S.A)

f.       Y-tube standard beams with slab

3.what is main advantage of prestressed concrete bridge deck.

•  High-strength    concrete      and    high-tensile steel,    besides    being    economical, make for slender  sections, which     are aesthetically    superior.

·        Segmental construction is ideally suited for post -tensioning work.

·        Post-tensioning facilities the use of curved slabs hich improve the shear resistance of girders.

4.Typical types Of Post-Tensioned Prestressed Concrete Bridges .

a.     Solid slab (10-15m)

b.     Hollow slab(15-25m)

c.      Tee  beams(20-40m)

d.     Box girders, two cell(30-70m)

e.      Box girders ,trapezoidal (30-80m)