WELCOME TO CIVIL ENGINEERING DEPARTMENT

COLUMBIA INSTITUTE OF EGINEERING AND TECHNOLOGY, RAIPUR

ANALYSIS OF PRE-STRESSED BRIDGE CONSTRUCTION

Guided by:-

Mr. K. Durga Prasada Rao

civil department

Team members

KAMAL KISHOR

NITESH KUMAR VERMA

PRASHANT DIWAN

VINAY ALOK MAKHIJA

DEEPAK SHORI

What is bridge?

A structure built to provide passage over a river, canal, road or any other physical hurdle . The function required from the bridge and the area where it is constructed decides the design of the bridge

or

A bridge is a structure providing passage over an obstacle without closing the way beneath.

or

The required passage may be for a road, railway, pedestrians , canal or pipeline.

Danyang–Kunshan Grand Bridge in china

The world's longest Rail-road Bridge is the Danyang–Kunshan Grand Bridge in China, part of the Beijing-Shanghai High-Speed Railway. The bridge, which is opened in June 2011, spans 102.4 miles (165 kilometers).

China constructed the Danyang–Kunshan Grand Bridge in just 4 years, employing 10,000 workers, at a cost of about $ 8.5 million. It crosses low rice paddies, part of the Yangtze River Delta, with just a few miles of the bridge actually crossing the open water of Yangcheng Lake in Suzhou. The bridge elevates about 100 feet (31 meters) off the ground.

The world's longest road bridge is the 34-mile (55-km) long Bang Na expressway in Thailand, a six-lane elevated highway that crosses only a bit of water, the Bang Pakong River. Constructing the massive bridge required more than 18,00,000 cubic meters of concrete.

1.Classification of Bridges (According to form (or) type of superstructures)

•Slab bridge

•Beam bridge

•Truss bridge

•Arch bridge

•Cable stayed (or)suspended bridge

2.Classification of bridges (According to material of construction of superstructure)

•Timber bridge

•Concrete bridge

•Stone bridge

•R.C.C bridge

•Steel bridge

•P.C.C bridge

3. Classification of bridges (According to inter-span relationship)

•Simply supported bridge

•Cantilever bridge

•Continuous bridge

5. Classification of bridges (According to method of connection of different part of superstructures)

•Pinned connection bridge

•Riveted connection bridge

•Welded connection bridge

6.Classification of bridges (According to length of bridge)

•Culverts (less than 6 m)

•Minor bridges(more than 6 m- less than 60m)

•Major bridges(more than 60 m)

•Long span bridges(more than 120 m)

7.Classification of bridges (According to function)

•Aqueduct (canal over a river)

•Viaduct(road or railway over a valley or river)

•Pedestrian bridge

•Highway bridge

•Railway bridge

•Road-cum-rail or pipe line bridge

What Is Pre-Stressed Concrete

Pre-stressed concrete is basically concrete in which

internal stresses of a suitable magnitude and distribution are introduced so that the

stresses resulting from external loads are counteracted to a desired degree. In

reinforced concrete members, the pre-stress is commonly introduced by tensioning the

steel reinforcement.

The earliest examples of wooden barrel construction by force-fitting of metal bands and

shrink-fitting of metal tyres on wooden wheels indicate that the art of pre-stressing has

been practiced from ancient times. The tension strength of plain concrete is only a

fraction of its compressive strength and the problem of it being deficient in tensile

strength appears to have been the driving factor in the development of the composite

material known as “reinforced concrete”.

*The idea of pre-stressing to counteract the stresses due to loads was first put forward

by the Austrian engineer Mandi in 1869. M Koenen, of Germany.

Types Of Pre-Stressing

• Pre-Tensioning

A method of pre-stressing concrete in which the tendons

are tensioned before the concrete is placed. In this method, the pre-stress

is impacted to concrete by bond between steel and concrete.

• Post-Tensioning

A method of pre-stressing concrete by tensioning the

tendons against hardened concrete. In this method, the pre-stress is

impacted to concrete by bearing.

What is Post-Tensioning

Post-tensioning is a technique used for reinforcing concrete structures . In this technique high tension steel cables placed through plastic ducts or sleeves positioned before the concrete is placed. Afterwards, once the concrete has gained strength but before the service loads are applied, the cables are pulled tight, or tensioned, and anchored against the outer edges of the concrete.

Pre-stressing simply means that the steel is stressed (pulled or tensioned) before the concrete has to support the service loads. Most precast, pre stressed concrete is actually pre-tensioned-the steel is pulled before the concrete is poured. Post-tensioned concrete means that the concrete is poured and then the tension is applied-but it is still stressed before the loads are applied so it is still pre stressed.

Components of Bridge

The various stages of the post-tensioning operation are summarised as follows.

1) Reinforcement and Placement of the tendons (High tension cables).

2) Casting of Bridge Deck.

3) Placement of the anchorage block and jack.

4) Applying tension to the tendons.

5) Seating of the wedges.

6) Cutting of the tendons

Post tensioning bridge

Hydroullic tensioning jack

The essential devices for post-tensioning are as follows.

1) Casting bed

2) Mould /Shuttering

3) Ducts

4) Anchoring devices

5) Jacks

6) Couplers (optional)

7) Grouting equipment (optional).

FIELD DATA

Construction of HL Bridge across Chhokra nalla on Saddu-Urkura Road Chhokra nalla on Saddu-Urkura Road SPAN NO-A1-P1

1 Area of Strands and value of ‘E’ as per test Report (Actual value)

S. No. Coil No. Area of Strands Value of ‘E’

i 819287/3 99.45 mm2 20045.00 Kg/mm2

ii 819287/1 100.26 mm2 20010.00 Kg/mm2

iii 819287/3 99.51 mm2 19985.00 Kg/mm2

Average area 99.740 mm2 20013.33 Kg/mm2

Or 2.00x104

2 Area of Strands and value of ‘E’ as per Drawing No. 132/W/CE/ RYP 2015 Dated 31-03-2015

(i) Area of Strand (A) - 98.7mm2

(ii) Value of ‘E’ - 2.00x104 Kg/mm2

(Modulus of Elasticity)

Modified Extension=

Design Extension in mm x 98.7 x 2.00 x 104

(Actual area in sq. mm. x Actual (E) in kg/mm2

= Design Elongation X98.70 x 2.00 x 104

99.923 x1.99 x 104

= Design extension X 0.99455

3 Modified Extension

Cable group. Cable No. Extension as per Design in mm Modified Extension (mm)

D 1,2,3 2 123.000 246.00 244.66I 4,5,6 2 123.000 246.00 244.66II 7,8,9 2 123.000 246.00 244.66III 10,11,12 2 123.500 247.00 245.65IV 13,14,15 2 123.500 247.00 245.65V 16,17,18 2 122.000 244.00 242.67VI 19,20,21 2 122.500 245.00 243.66VII 22,23 2 75.000 150.00 149.18VIII 24,25 2 52.000 104.00 103.43IX 26,27 2 75.000 150.00 149.18X 28,29 2 52.000 104.00 103.43

4 Calculation of Dial Gauge Reading

(i) Force applied in each end as per drawing = 169.4 Tonne 14.11666667Each cable force = 169.40/12 14.117Tonne

(ii) Area of Ram of Jack (as per test certificate) = 482.400 cm2

Pressure on dial gauge = 169400= 351.1608624 Kg/cm2

482.400 cm2

Say 351 Kg/cm2

(a) Maximum Pressure = Design Pressure + 5% = 368.55 Kg/cm2

Say = 369.00kg/cm2

(b) Minimum Pressure = Design Pressure – 5% = 351 x 0.95 = 333.50 Kg/cm2

Say = 334.00 kg/cm2

Cable Stressing Testing Results

Cable group. Cable No.Modified

ElongationTotal slip in mm ( 2x6 = 12 mm)

Net elongation required in mm

Maxi.+ 5% Mini.-5%

1 2 3 4 5 6

D 1,2,3 244.66 -12 232.66 244.29 221.03

I 4,5,6 244.66 -12 232.66 244.29 221.03

II 7,8,9 244.66 -12 232.66 244.29 221.03

III 10,11,12 245.65 -12 233.65 245.34 221.97

IV 13,14,15 245.65 -12 233.65 245.34 221.97

V 16,17,18 242.67 -12 230.67 242.20 219.14

VI 19,20,21 243.66 -12 231.66 243.25 220.08

VII 22,23 149.18 -12 137.18 144.04 130.32

VIII 24,25 103.43 -12 91.43 96.00 86.86

IX 26,27 149.18 -12 137.18 144.04 130.32

X 28,29 103.43 -12 91.43 96.00 86.86

LOCATION

Project Scope

Location/Survey

Final Design

Construction

Preliminary Design

Bridge Design Process

•Function (To bridge or not? Replace or remove?)

•Who is User?

•Where is best spot?•Many decisions.

•Project Funding andScope finalized.

•Plans, Specs,Estimates.

PRELIMINARY SURVEY

In General Bridge Preliminary Survey Involves

Topography

Catchment area

Hydrology

Geo-technical data

Seismology

Construction resources

Pile foundation and pile capPile foundations are the part of a structure used to carry and transfer the load of the structure to the bearing ground located at some depth below ground surface. The main components of the foundation are the pile cap and the piles. Piles are long and slender members which transfer the load to deeper soil or rock of high bearing capacity avoiding shallow soil of low bearing capacity The main types of materials used for piles are Wood, steel and concrete.

Piers of bridgeWherever possible slender piers should be used so that there is sufficient flexibility to allow temperature, shrinkage and creep effects to be transmitted to the abutments without the need for bearings at the piers, or intermediate joints in the deck.

BearingBridge bearings are devices for transferring loads and movements from the deck to the

substructure and foundations.In highway bridge bearings movements are accommodated by the basic mechanisms of internal deformation (elastomeric), sliding (PTFE), or rolling. A large variety of bearings have evolved using various combinations of these mechanisms.

Deck Slab of Bridge : Deck Slab is the top most part of the bridge Structure . Which is the major element of the super structure it is directly take load and transfers into columns

Joints :The objective is to avoid the use of joints over abutments and piers. Expansion joints are prone

to leak and allow the ingress of de-icing salts into the bridge deck and substructure. In general all bridges are made continuous over intermediate supports and decks under 60 metres long with skews not exceeding 30° are made integral with their abutments.

Parapet and drainage:Parapet as a safety barrier that is installed on the edge of a bridge or on a retaining wall or

similar structure where there is a vertical drop, and which may contain additional protection and restraint for pedestrians and other road users.

MATERIALS USED FOR BRIDGE

Concrete grade

M25 for foundation work (1:1:2)(nominal)

M30 for piers (Design mix)

M35 girder and deck construction (Design Mix)

Concrete is supply by RMC plant ( SKM)

Reinforcement bar

6 mm & 8 mm in deck

8 mm & 10 mm in girder

10 mm & 18 mm in piers

10 mm & 25 mm use in piles

High tensioned wire for stressing of girder.

INTRESTING FACTS ABOUT THE BRIDGE

Total length of bridge is 144 meter

72 meter saddu side ,and 72 meter urkura side

Deck elevated from ground level is 6 meter.

There is 4 span and 3 piers , each span is 35.5 meter long and width of 12 meter.

Each piers having 4 piles of 1meter dia.

Total estimated cost of bridge is 9 carore but due some delay budget is increased by 14 carore .

Bridge under constructed on PWD Raipur.

For designing of bridge in working stress method.

BRIDGE AFTER COMPLETION