WorldWide Drilling Resource®

The Elbtower Foundation Piles Set New Record Adapted from Information by BAUER Group A project in Hamburg, Germany, will be Europe’s largest inner city development project to date, the futuristic HafenCity district. The Elbtower will be the final building of the project, and towering more than 800 feet above the ground, it will be the tallest building in Hamburg, and the third tallest high-rise in Germany after the Commerzbank Tower and the Messeturm (trade fair tower) in Frankfurt am Main. Elbtower will be situated between the bridges over the Elbe river and will include an observation deck, as well as office and retail space, hotel, boarding house, coworking spaces, fitness and wellness areas, as well as a children’s play area. There will also be around 600 parking spaces and a boat storage. There is even talk of building a restaurant near the top of the tower. Before the structure can be built, the foundation must be studied and test piles need to be drilled. BAUER Spezialtiefbau GmbH was hired to conduct the load testing using test piles built specifically for this project. The ground surface near the river has a low load-bearing capacity due to the area’s deep, cohesive soil stratum. This means the structural load will have to be shifted to the subsoil, which has deeper, load- bearing soil stratum, to prevent the building from settling. BAUER installed the initial test piles to a depth of about 365 feet and a diameter of nearly 73 inches making it the longest piles ever installed in Germany. “The load tests with the test piles will allow us to analyze the ground behavior and structural load in order to determine the most eco- nomical foundation,” said Andreas Wedenig, project manager at BAUER Spezialtiefbau. “Two of our test piles will be subsequently integrated in the finished building. Two are only for testing purposes.” The test piles are slurry-stabilized large-diameter bored piles, installed using the kelly method. Using this method, drill tools are attached to a telescopic kelly bar, while the ground is incrementally dissolved and brought to the surface. Typically, this process uses a steel casing pipe placed in the ground before the work be- gins. The extreme depths required for this project caused the team to skip the pipe work as much as possible. Slurry stabilization was used instead. With this procedure, the excess fluid pressure prevented the walls of the borehole from collapsing. Once the planned drilling depth was achieved, the sand was removed from the suspension and a reinforcement cage was built. Cement was then pumped in to fill the borehole from bottom to the top, pushing the suspension to the top of the borehole. One of the unique parts of this project is the pile test is carried out near the base of the pile using an Osterberg cell, which is a hydraulic loading device built into the reinforcement cage, where it loads the pile from below. “The actual foundation works are planned to begin [this year]; then more than 100 of these large-diameter bored piles will be created. The length, diameter, material, formation, and placement of the piles can vary according to the results of the load tests,” explained Wedenig. Groundbreaking for the Elbtower is scheduled for 2021, with completion expected by 2025. New England Water Well Association c/o Markets Beyond Group 7 Bailey Lane, Brewster NY 10509 Phone: 845-278-1892 Fax: 845-278-1899 Pre-Registration $ 20 per person Spouse &Children under 16 years FREE Onsite Registration $ 25 Registrant (s) Names: Contact: Address: State/Zip Code: Phone & Fax : E-mail: Pre-Registration Deadline - March 1, 2020 Pre-Registration NEWWA New England Water Well Expo March 13 - 14, 2020 Best Western Royal Plaza Trade Center Marlborough, Massachusetts Credit Card Type __________ Credit Card Number ________________________ Expiration Date ________________CCV (security code)_______ Complete this form and fax or mail it along with your payment ASAP to NEWWA. Register online at e Swap Meet Bring whatever fits in a pickup truck. $50 preregistration or $75 at door . 16 FEBRUARY 2020 WorldWide Drilling Resource ® Good morning, . . . I've enjoyed immensely the articles, news, and everything in be- tween from cover to cover in WWDR magazine for about the past 5 years . . . Thank you all again for [your] hard work and dedication. Genuinely, Adam Andrews Trained drilling and blasting technician and safety enthusiast C&G