Job Reports
HALYVOURGIKI S.A.

PHASE ONE: Foundation of the metal building of the New Rolling Mill ΙΙ – Static designs for the foundation and the pile caps.
PHASE TWO: Construction of foundation piles for the above ground structures of the New Rolling Mill ΙΙ, the Power Station, the Furnace and the Wastewater Treatment unit, plus construction of lateral support piles for the reservoir of the New Wastewater Treatment unit.
PHASE THREE: Construction of foundation piles for the metal buildings of the Iron Warehouse and the Mesh Line Warehouse III.

Technical description:

PHASE I:
Construction of 80 Φ800mm bored piles from the –3.40 to the –18.00 level, for the foundation of the metal building of the new Rolling Mill ΙΙ. The construction of the bored piles includes the penetration of the armoured concrete flooring with a core barrel, the drilling of the hole, the supply / construction and placement of the steel armouring, the concretisation of the pile with C20/25 concrete (400kg/m3), the backfilling of the chimney with metal from the 0.00 to the –2.25 level, and the loading and removal of the materials dug out during the excavation of the piles. Thereafter, construction of the pile caps and of the bind beams connecting the pile caps, as well as placement and compaction of the earth anchors supporting the pillars of the metal building. The construction of the pile caps includes the demolition of the armoured concrete flooring, the excavations of the trenches down to the –3.40 level, the pumping works, the metal drainage floor, the lean concrete, the concretisation of the pile caps and of the bind beams with C20/25 concrete (400kg/m3) and the backfilling and condensation of the trenches with rip-rap and metal.

PHASE II:
Construction of 47 Φ800mm bored piles from the –0.80 / –3.75 to the –17.00 / –18.50 level, as well as of 313 Φ1000mm bored piles from the –0.80 / –4.70 to the –18.00 / –21.00 level, for the foundation of the above ground structure of the buildings for the new Rolling Mill ΙΙ, the Power Station, the Furnace and the Wastewater Treatment unit. The construction of the bored piles includes the penetration of the armoured concrete flooring with a core barrel, the drilling of the hole, the supply / construction and placement of the steel armouring, the concretisation of the pile with C20/25 concrete (400kg/m3), the backfilling of the chimney with metal from the 0.00 to the –3.00 level, and the loading and removal of the materials dug out during the excavation of the piles.
Also, construction of 70 Φ1000mm intersecting piles from the –2.10 to the –18.00 level, for the lateral support of the reservoir of the new Wastewater Treatment unit. The construction of the bored piles includes the same works mentioned above.

PHASE III:
Construction of 10 Φ800mm bored piles from the –1.43 to the –18.18 level for the foundation of the metal building of the Mesh Line Warehouse ΙΙΙ, as well as of 35 Φ1000mm bored piles from the –2.80 to the –18.50 level for the foundation of the metal building of the new Iron Warehouse. The construction of the bored piles includes the penetration of the armoured concrete flooring with a core barrel, the drilling of the hole, the supply / construction and placement of the steel armouring, the concretisation of the pile with C20/25 concrete (400kg/m3), the backfilling of the chimney with metal from the 0.00 to the –1.00 level, and the loading and removal of the materials dug out during the excavation of the piles.


Description of the construction procedure:

For the construction of the piles, geotechnical engineering considerations prior to the start of works determined the optimum method for the drilling of the piles. With a drilling machine, and using a core barrel, penetration was carried out to the –4.00 level. Using a PTC-50 vibrator fitted on a Hitachi 150 crane with vertical boom, Φ800mm or Φ1000mm piping was rammed down to the –16.00 level. Then, the drilling machine dug through the pipe down to the tip of the pile, the armouring was placed using an auxiliary crane (Hitachi 100) and, once the pile was concretised, the piping was removed by use of the vibrator. In the case of the 20 Φ1000mm bored piles constructed inside the existing Rolling Mill, due to the limited height, the same method was used but with the vibrator hanging from a Liebherr crane. The construction of the Φ1000mm intersecting bored piles required the use of a larger drilling machine, a Casagrande B-250 with Twister, and double-case piping.

This particular method for the construction of the piles by using piping and a vibrator proved to be totally satisfactory, less expensive than the one using bentonite mud (less overconsumption of concrete) and executable in a short period of time. The completion of the foundation works ahead of the scheduled short period contributed to the prompt finalisation and operation of the new production complex of HALYVOURGIKI SA.