The famous Hollywood sign in California for many decades now has been a landmark recognized by people all over the world. Today, however, it provides the backdrop for a water quality improvement project being conducted by the Los Angeles Department of Water & Power.
Within the shadows of the Hollywood sign, the city installed two new water tanks capable of holding 31 million gallons each that will help to provide cleaner and safer water to the many people in the Los Angeles area. The location of these water tanks is situated on very steep embankments that required the installation of over 1260 tie backs to secure the tanks in-place and prevent any cause for alarm in the local community.
At the outset of the project, the LA Department of Water & Power searched for a company experienced in this type of application and that could complete the project on-time and within budget. Having over 50 years of experience in the construction industry and a top-notch reputation for satisfying project requirements, Kiewitt Pacific was the natural choice to plan and execute this project without incident.
In order to properly secure the two tanks in-place, project specifications called for 1260 tie back sockets to be drilled into the mountainside to a depth of 125 feet (38 m). Ground conditions complicated matters because they consisted of various formations of medium to hard consistencies. To conquer this demanding environment, Kiewitt Pacific sub-contracted the installation of the tie backs to drilling contractor, Condon Johnson, who is well-known for having great success in this type of application. Condon Johnson sought the advice of John Hagfors of Hennessy International who recommended the purchase of Numa Champion 50 down hole hammers and 6 inch (152 mm) bits due to their reputation for durability, providing long life and producing fast penetration rates.
Numa’s Champion 50 hammer is capable of drilling holes from 5-1/8″ to 6″ (130 – 152 mm) in diameter for vertical and horizontal applications. Designed for long life and fast penetration rates in hard rock conditions, the hammer is perfectly suited for completing tie backs, rock sockets, water wells, exploration drilling, blast holes or any other rock drilling project.
To conduct the drilling, Condon Johnson used three (3) Klemm 806 drill rigs to power the Numa Champion 50 hammers along with 900 cfm / 300 psi (425 l/sec 20.4 bar) of air. Once a rig was positioned at the tie back location, the Champion 50 would drill a 6 inch (152 mm) hole to a depth of 125 feet (38 m). Tie back rods were also inserted into the sockets to lock into the formation and secure the tanks in-place. A total of 110,000 feet (33,550 m) was drilled with the Champion 50 hammers with each rig being able to complete 8 – 10 holes per day.
Although the water tanks in the Hollywood hills will never be as famous as the sign that stands above them, they will play a much more important role in the surrounding community. Both tanks will provide the people that live and work in the area with a vital supply of clean water that was made possible through the outstanding joint efforts of the LA Dept of Water & Power, Kiewitt Pacific, Condon Johnson, Hennessy International and Numa.