PYRA­MID PUMP­ING

Con­struc­tion Week ex­plores Uni­bet on Ready Mix’s con­crete pump­ing op­er­a­tion for the Medium Pyra­mid ho­tel apart­ments at Fal­con city of Won­ders Dubai

Construction Week - - CONTENTS - WORDS BY DEN­NIS DANIEL

CW ex­plores Uni­beton Ready Mix’s con­crete pump­ing work at Fal­concity

Con­crete pump­ing is the fi­nal, crit­i­cal link in the jour­ney of ready-mix con­crete from a batch­ing plant to var­i­ous heights and depths on a con­struc­tion site. Th­ese op­er­a­tions re­quire ex­per­tise in se­lec­tion of the ap­pro­pri­ate sta­tion­ary or mo­bile pumps, in­stal­la­tion and test­ing of the pumps, and sched­ul­ing con­crete batch­ing and de­liv­ery ac­cord­ing to real-time con­struc­tion ac­tiv­ity. The to­tal amount of con­crete re­quired for a con­struc­tion site is usu­ally spec­i­fied for the en­tire year, and monthly de­liv­ery sched­ules are fi­nalised in ad­vance.

In prac­tice, con­crete de­liv­ery and pump­ing sched­ules for con­struc­tion ac­tiv­i­ties, such as pil­ing, are con­firmed a day in ad­vance by the en­abling works contractor in ac­cor­dance with the quan­tity of con­crete re­quired for the day, and the progress of drilling and in­stal­la­tion of re­in­forc­ing steel cages. To find out more about the con­crete

pump­ing process and its lo­gis­tics, Con­struc­tionWeek joined Uni­beton Ready Mix on one of its ready-mix con­crete de­liv­ery and pump­ing op­er­a­tions in Dubai.

The con­struc­tion site was of the Medium Pyra­mid ho­tel apart­ment build­ing at the Fal­concity of Won­ders, where Mid­dle East Foun­da­tions Group, the en­abling works contractor, is com­plet­ing pil­ing works.

The Medium Pyra­mid (B+G+19 +health club) is one of three pyra­mids – named Small, Medium, and Large – to be built at the Pyra­mid’s Park in Fal­concity of Won­ders, em­u­lat­ing the Egyp­tian ar­chi­tec­tural won­der. Ac­cord­ing to the de­vel­oper, Large Pyra­mid will be the big­gest pyra­mid ever built and will func­tion as a mixed-use com­plex com­pris­ing res­i­dences, of­fices, and other recre­ational av­enues.

Since June 2018, Uni­beton has de­liv­ered 26,000m3 of con­crete to the Medium Pyra­mid site for the con­struc­tion of 520 piles. Each pile re­quired 50m3 of con­crete trans­ported in five mixer trucks and poured through a truck-mounted con­crete pump. Drilling at the Medium Pyra­mid site was done at night, and re­in­forc­ing steel cages were in­stalled early in the morn­ings. As a re­sult, con­crete pil­ing work was con­ducted dur­ing day­time.

Se­nior gen­eral man­ager at Uni­beton, Talaat Mouin Abdul Karim, ex­plains the or­der­ing and de­liv­ery process: “We pro­duce con­crete batches for pil­ing ac­cord­ing to the mix de­sign spec­i­fied by the en­abling works contractor. The con­crete strength spec­i­fied for this project is 60N/mm2. The en­abling works contractor also con­firms the ready-mix con­crete quan­tity re­quired for a day and the time of pump­ing. Once we re­ceive the book­ing, we as­sign truck-mounted pumps to the site,” says Karim. The or­der is re­con­firmed on the day of the pump­ing and Uni­beton starts con­crete batch­ing only af­ter the in­stal­la­tion and test­ing of the con­crete pump by the com­pany’s staff. This al­lows the com­pany to dis­patch its mixer trucks in a way that al­lows them to ar­rive on site just in time for slump test­ing and con­crete pump­ing. When a truck-mounted pump reaches its site, Uni­beton’s staff in­spects the en­trance and ac­cess points for pump in­stal­la­tion and en­sures that the land is well com­pacted for sta­bil­ity of the pump. “Se­lect­ing the right lo­ca­tion for in­stal­la­tion of the con­crete pump is a cru­cial part of the process. If the land

“SE­LECT­ING THE RIGHT LO­CA­TION FOR IN­STAL­LA­TION OF THE CON­CRETE PUMP IS A CRU­CIAL PART OF THE PROCESS.”

– TALAAT MOUIN ABDUL KARIM, UNI­BETON

is un­even or un­sta­ble, we alert the en­abling works contractor to com­pact the [space]. Only then can we in­stall and test the pump,” says Karim.

Uni­beton as­signs up to four staff on site for qual­ity con­trol, su­per­vi­sion, and as­sis­tance. This group in­cludes a su­per­vi­sor, a tech­ni­cian for slump tests, a con­crete pump op­er­a­tor, and a helper.

“The qual­ity con­trol process starts with the batch­ing of the con­crete, fol­lowed by slump tests at the batch­ing plant as well as on site, in or­der to en­sure the con­sis­tency of the con­crete in ac­cor­dance with the mix de­sign. Sub­se­quently, the con­crete is ap­proved for pump­ing. If the slump value is low, the pump will not be able to func­tion, and the batch will be re­jected from the site,” says Karim.

Uni­beton main­tains a fleet of 253 mixer trucks and 61 truck-mounted, mo­bile con­crete pumps in the UAE to trans­port and pour ready-mix con­crete. The com­pany’s mixer trucks have 9m3 and 12m3 ca­pac­i­ties, and the av­er­age out­put ca­pac­i­ties of its con­crete pumps is 70-80m3/ h.

Ac­cord­ing to Karim, a de­liv­ery of 50m3 of con­crete would re­quire five 12m3 mixer trucks. High-slump con­crete is used for pil­ing, and so, the trucks are loaded un­der full ca­pac­ity in or­der to main­tain the con­sis­tency of the con­crete and avoid spillage on the road.

“We are able to batch and de­liver ready-mix con­crete within an hour af­ter re­ceiv­ing con­fir­ma­tion from the site. The con­crete batch­ing process re­quires about 5-7 min­utes, and it is de­liv­ered to the site in 50-60 min­utes,” says Karim.

The time re­quired for con­crete pump­ing is al­most the same as that re­quired for batch­ing. Each mixer truck takes 7–8 min­utes to trans­fer all its con­crete to the pump. If the time re­quired for the trucks to en­ter and leave the site and con­nect with the truck­mounted pump is con­sid­ered, it takes about an hour to pump 50m3 of con­crete for a pile.

“The amount of con­crete to be pumped for pil­ing de­pends on the di­men­sions of a pile and its load bear­ing re­quire­ments. It’s com­mon for con­struc­tion sites in the UAE to have 100m3 of con­crete per pile. We pumped 250m3 of con­crete to con­struct a sin­gle pile at the Shindagha Bridge project in Dubai,” says Karim.

Uni­beton is not a stranger to push­ing the bound­aries of con­crete pour­ing. In 2016, the com­pany set the Guin­ness World Record for pour­ing more than 19,793m3 of con­crete con­tin­u­ously for 42 hours at Geepas Tower in Al Bar­sha, Dubai. The con­crete was de­liv­ered us­ing 300 mixer trucks that made more than 2,500 trips from three plants, and con­crete pour­ing work was car­ried out with 14 pumps on site. An ad­di­tional five pumps were on standby. Six hun­dred work­ers were em­ployed in mul­ti­ple shifts to work round-the- clock and com­plete the job.

One of the pop­u­lar truck-mounted con­crete pump mod­els used by Uni­beton reg­u­larly is the Sch­wing Stet­ter S42SX, which has a max­i­mum ver­ti­cal reach of 42.1m and hor­i­zon­tal reach of 38.1m. Its max­i­mum con­crete out­put is 162m3/ h at a max­i­mum pres­sure of 85 bar on the con­crete. The tur­ret can be ro­tated 370° in either di­rec­tion and the tip sec­tion can ro­tate 240°.

“The length of the boom de­ter­mines the reach of the pump in a pil­ing area. The longer the boom, the more the con­crete piles can be cov­ered by a truck­mounted pump from a fixed po­si­tion of the truck. This saves time and avoids the need to cre­ate ac­cess points on large sites, par­tic­u­larly those with low- qual­ity soil,” says Karim. “Con­crete pumps such as the Sch­wing Stet­ter S42SX are work­horses de­signed to op­er­ate 24 hours. We’ve used Sch­wing Stet­ter pumps to de­liver 800m3 of con­crete in 24 hours at an av­er­age rate of 40m3 per hour for a foun­da­tion project in the UAE. Such pump­ing ca­pac­i­ties have been tried and tested and can be guar­an­teed for any project.”

Karim elab­o­rates on the com­pany’s main­te­nance process for con­crete pumps, which he says is vi­tal to avoid project de­lays: “Truck-mounted con­crete pumps move from one site to an­other, and we of­ten as­sign a pump on two or three sites a day. Gen­er­ally, we as­sign a sin­gle truck­mounted pump to a site, un­less it’s a large project that can­not af­ford down­time and re­quires standby pumps.

“The com­mon is­sue fac­ing mixer trucks and pumps is break­down and re­lated down­time costs. We have im­ple­mented sched­uled in­spec­tion and main­te­nance pro­cesses to avoid such is­sues. It’s rel­a­tively easy to fix a truck. How­ever, a con­crete pump break­down could cause sig­nif­i­cant de­lays. There­fore, we do not com­pro­mise on the qual­ity or main­te­nance of our con­crete pumps,” says Karim.

No­table Abu Dhabi de­vel­op­ments, in­clud­ing Fer­rari World, are a part of TSES’s port­fo­lio.

Uni­beton broke the Guin­ness World Record for con­crete pour­ing in 2016.

Choos­ing the right lo­ca­tion to set up a pump is a cru­cial part of the process.

The Sch­wing Stet­ter is a trusted work­horse of con­crete pour­ing rms.

It is com­mon for UAE con­struc­tion sites to have up to 100m3 of con­crete per pile.

Fal­concity of Won­ders will fea­ture the world’s largest pyra­mid when it’s built.

Uni­beton says com­pro­mis­ing on the qual­ity of ve­hi­cle in­spec­tions is in­ad­vis­able.

Newspapers in English

Newspapers from UAE

© PressReader. All rights reserved.