With the world tallest building (160 floors) completed in 2008 in Dubai (the Burj Dubai Tower)
reaching 1988.19 Ft (606 meters), the high-rise building industry has come a long way. From its humble beginning hand carrying small concrete buckets, to large buckets being lifted by cranes, the ever growing needs of long distance line pumping has pushed concrete pumps manufacturers to reinvent its technology to respond the ever growing new demands.
Some of the challenges:
When the city of Taipei decided to build in 1998 its Taipei 101 Tower/Financial Center (1,667 feet), the project was even more challenging than Dubai because of the known risks of typhoons, high winds and earthquakes. As a result, the building is able to withstand winds up to 133 miles per hour and 7-point earthquakes! This required concrete filled steel mega columns, mega-truss, a truss structure at the core, a Tuned Mass Dumper System and a 800-ton spherical steel ball suspended like a pendulum! Not your average hi-rise engineering design!
The challenge in long-distance pumping isn’t only the pumping but it is the logistics. How much pipe, hose, elbows, thrusts blocks, anchors ? How many guys you need on-site? Who will set up what by when?
When building structures reach over 1900 feet, concrete has to flow and remain longer in the delivery line (anywhere around 35 minutes). This means that the entire content of the pump chamber has to move through with each motion (piston or peristaltic) otherwise any concrete residue can harden, wear out moving parts and cause serious damage.
Projects placing higher concrete volumes require additional planning and design for pump lines. You will need 1.1 pounds of pressure, when using a standard 5-inch standpipe to move concrete one vertical foot. So, if you need to pump 1000 vertical feet, you will need at least 1.1 pounds of pressure. There is nothing better to understand the complexity involved in vertical pumping the projects than see it. So we have compiled a short series of videos showing long-distance concrete pumping on various projects around the world.
Vertical pumping also requires thorough testing of concrete performance at the batching plant, measuring concrete obtain with various pump types, output and the inner pressure of the pipe. In addition core tests and porosity tests were conducted. In the case of the Taipei financial center, a Schwing BP 8000 HDR pump was selected for consistent output and quality of concrete pumped. For the Burj Dubai Tower, 3 Putzmeister 14000 SHP D super high pressure pumps pumped a total of 165,000 m3 of high-strength concrete over a period of 32 months! Now, that’s durability! The frame, hopper, S-transfer tube and bearings have been enhanced to handle the tremendous force.
Tips From the Pros:
As a rule of thumb, the pipe’s diameter should be minimum 3-4 times the size of the largest aggregate size. When pumping concrete against gravity (vertically), a diameter smaller than the usual 125 mm pipeline should be used. It is absolutely necessary to anchor riser pipelines to the structure for the duration of the project. Pipe bends can be secured by casting them through concrete “thrust blocks”.
Be careful and always top the feeder hopper. NEVER let air into the line, especially at the beginning of the pouring job. Hose whipping is the number one cause of injuries and death on the job. When pumping at great heights, this danger is multiplied. To find out how to avoid hose whipping on the job, you can read this article.
Slump loss isn’t usually a common problem when pumping long-distance especially when the aggregate absorption is low. The key is to keep the aggregate wet during the project. This can easily be accomplished in hot regions with sprinklers watering aggregate piles.
The country of Saudi Arabia is developing various hi-strength high-rise concrete mixes (Saudi Readymix Concrete) to be used in conjunction with advanced pumping techniques for the exploding construction market in this region of the world. Their high alumina cement content is heat resistant (up to 1500 C), ideal for building in the Middle East.
At United Equipment Sales, we carry all major pump brands like Schwing, Putzmeister, Reed, Mayco, Olin and more that can handle just about any job size. Below are some examples. Give us a call at (503)283-2105 if you have any questions on pumps, hose and accessories.
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