104" Valve Installing Projects
As part of Mekorot’s preparations for an earthquake scenario, a decision was made to install a 104" diameter butterfly separating valve at the national water carrier pipeline (110" diameter) running though the Jezreel Valley near Kfar Yehoshua.
At this point, the water carrier pipeline is laid at a depth of about 5 meters in clay soil earth saturated with ground water. The level of the ground water is about 1.5 m. below ground level. The granular and sand filling surrounding the pipeline along a route of several kilometers serves to drain groundwater towards it. This required massive and continuous pumping, 24/7, throughout the entire period of installing the valve, until the water level was sufficiently reduced.
The valve was installed inside a 13 m. X 18 m. concrete pit at a depth of 6 meters below ground level. In order to facilitate the operation of the valve during an electricity blackout, a backup diesel generator was installed in a dedicated building.
In order to ensure maximum safety, to refrain from encroaching on private land and to pump all the groundwater, it was necessary to drill and pour concrete pilings along the walls of the pit and at a distance of 2 meters from the pit. The pit itself was reinforced with pilings and the ground beneath the pit was replaced and stabilized to a depth of 1 m.
Due to the close proximity to the water carrier pipeline, and to avoid damaging the pipeline during excavation, the work is being carried out in 3 stages.
Stage 1 – Drilling and pouring reinforced concrete pilings and foundation pilings.
Stage 2 – Excavation during the suspension of the water carrier’s operation he in 2013 and continuation of the construction of the pit.
Stage 3 – Installation of the valve and accompanying systems during the suspension of the water carrier’s operation in 2014 and the completion of the project.
The installation of a valve of such a diameter and of the surrounding systems requires professionalism and maximum accuracy, as well as total compliance with all safety regulations.
The project is being carried out by a team of welders from the Northern Operations Unit under the helm of Tarabish Salman, with Khaled Kafini – the head of the welders team and Abdullah Kananba – the manager of the metal workshop and the welders. The teams were assisted by heavy 180 – 250 ton cranes.