Ferko Line Office and Hotel Project

The shoring design of Ferko Line Project; which has 9 m of excavation depth and partially underground water level was accomplished by KASKTAŞ. In order to perform the excavation in dry condition and safely without causing any hazard to surrounding structures and roads; topographic conditions and very soft to soft soil conditions encountered at the Project Site were taken into account for the shoring design. In the light of these prevailing site conditions, shoring system was selected as anchored diaphragm wall with one row of temporary ground anchors. Additionally, in order to improve the soil at the toe of the diaphragm wall, jet grout columns were executed.

Within the scope of the project, 12,500 m² of diaphragm wall, 33,150 m of foundation bored piles, 8,900 m of Single Bore Multiple anchor (SBMA) and 62,400 m of jet grout columns were completed. As per the strict quality control program, prism reflector, inclinometer and anchor load cells were placed, readings were recorded and evaluation reports were prepared.

High capacity (SBMA) technology; which is a proprietary product of KASKTAŞ has been successfully used for the first time in Turkey. Investigation tests were carried out before the commencement of anchoring works in order to verify that SBMA anchors can carry the design load of 40 ton in the prevailing sub-soil conditions. A maximum anchor capacity of 120 ton was achieved.

Two preliminary pile load tests were conducted under both core and podium areas. As a result of these tests, piles having a diameter of 100 cm and socketed into rock were shown to have a capacity of 1,450 ton. Test results have paved a way for optimization of diameter and number of piles.

In order to determine and select jet grout application parameters, preliminary test columns were installed at different part of the construction site. Full length corings were taken and tested by 3^rd Parties together with diameter control. Due to the strict and challenging work schedule, construction works are planned to be completed in 4 work areas of the site successively. Therefore, all sub-contract works; such as diaphragm wall, bored piles, jet grout columns, SBMA anchors and head beams were carried out within limited working conditions by using large number of machinery and equipment. The highest capacity ground anchors were successfully completed in very soft to soft soil conditions at Kağıthane, Istanbul. Moreover, this project will be the deepest and largest excavation in Kağıthane, Istanbul when it is completed.