FLY OVER NEAR SP OFFICE , KOLLAM

DETAILS OF FLYOVER

Width of road= 7.5m

Foot path of 1m on either sides only on a span crossing the railway line

Total Number of spans =11

HISTORY

1. FOUNDATION OF A PIER

A Pier is supported by 6 piles of diameter 1m followed by a pile cap. A pile has a length of 30 to

38m approximately and the width of pile cap is 4.3 m on which the peir is resting.

*M35 concrete with a maximum w/c of 0.4 and minimum cement content of 400 kg/m3 is used

for piles and for pile cap M 30 grade of concrete with a maximum w/c ratio of 0.4 and a

minimum cement content of 320 kg/m3 is used.

* A clear cover of 75 mm is provided for both pile and pile cap.

*Development length shall be 50 times the diameter

* Design load on each pile is 1900 KN

*Pile should go into a layer into a layer of hard cement clay with N value greater than 50 for a

minimum depth of one time the diameter of pile subject to an approximate length of 30 to 38 m

* The minimum slump for the pile concrete shall be 150-170mm

1.1 REINFORCEMENT DETAILS OF PILE

Main reinforcement of 12 mm around the circumference of the pile @ 90 mm c/c

Stirrups of 8mm @ 100 mmc/c

Fig: Reinforcement for a pile

1.3 REIFORCEMENT DETAILS OF PILE CAP

Main reinforcement of 25 mm @125 mm c/c at the bottom and 20mm @125 mm c/c at the top .

Stirrups of 12 mm @150mm c/c is used for the pile cap

A pile cap is constructed over 6 piles after cutting up to 1m length of pile for getting a fresh

surface

Fig: Pier constructed over pile cap

2.PILING

Method of piling used in the site was cast insitu driven pile. After the hole is driven to the

required depth as mentioned in the specifications, reinforcement which was already prepared was

transferred to the driven hole. Then a tremie pipe was inserted for the concreting operation and

the concreting operation is similar to that of underwater construction

Fig: Pile construction

3. PEIR

All the piers are constructed over a pile cap which is supported by 6 piles. The diameter of the

peir is about 1.8m which consists of 36 numbers of 28mm dia bars as main reinforcement and

stirrups of 12mm dia bars @125 mm c/c

Fig: Slabs supported by peir