Page 31

2017WinterShotcreteEMag

from the outside in: roof, insulation, and finally the structural concrete structure. All reinforcing bars and heavy equipment to be used in the project such as cranes and forklifts must be placed under the air form before it is inflated because once inflated, the form must remain under pressure for the duration of construction. The construction equipment only leaves the interior once the dome is complete. This meant a 38 ton (35 metric ton) mobile crane, a telehandler, and all the reinforcing bar had to be strategically positioned within the pile cap and under the air form prior to it being inflated. In February 2015, construction began on the Timaru dome, a 120 ft (36 m) diameter, 103 ft (31.5 m) tall dome. First, the custom-fabricated DomeSkin air form was carefully attached and bolted down to the foundation and then inflated. The dome was built following Domtec’s quality control methodology and safety procedures. 1923 yd3 (1470 m3) of shotcrete were placed in the dome along with 562 tons (510 tonnes) of reinforcing bar. After the Timaru dome was completed, Domtec’s specialty equipment was shipped to Auckland to build the 33,000 ton (30,000 tonne) cement storage dome there. The Auckland dome was 135 ft (41.2 m) Fig. 8: Typical dome structural reinforcing bar mat; over 550 tons (500 tonnes) of reinforcing bar was used in the Timaru dome diameter and 90.2 ft (27.5 m) tall and required approximately 529 tons (480 tonnes) of reinforcing bar and roughly 1400 yd3 (1100 m3) of shotcrete (Downer 2014). The dome structure stayed on schedule and was completed in 14 weeks from inflation of the air form to the final layer of shotcrete. Downer also worked closely with Domtec to create specific methodology and safety controls, and set up a workshop with WorkSafe NZ, the government’s health and safety regulator. The presentation was accepted the first time without any comments or changes. Overall, the two 33,000 ton (30,000 tonne) cement storage domes were built on-time and Domtec proved to be a suitable supplier to Holcim’s chosen General Contractor, Downer Group. This project marks the first two concrete domes in New Zealand and has overall been well received. To learn more about Holcim New Zealand, please visit www.holcim.co.nz. To learn more about Downer Group, please visit www.downergroup.com. To learn more about Domtec International, visit www.domtec.com. References Downer Group, 2014, “HOLCIM CMSP – Cement Storage Dome – Auckland,” Report on Dome Contractor Findings, Auckland, New Zealand. New Zealand Government, 2013, “2013 Census Usually Resident Population Counts,” Statistics New Zealand, http://www.stats.govt.nz/browse_for_stats/population/ census_counts/2013CensusUsuallyResidentPopulationCounts_HOTP2013Census/ Commentary.aspx#aucklandfastest. (last accessed April 20, 2016) Embedded premat First layer structural reinforcement First layer structural r reinforcement embedded Second layer structural reinforcement Fig. 9: View showing multiple phases of dome building process. Domtec shotcrete technicians average over 25 years of experience each www.shotcrete.org Winter 2017 | Shotcrete 29


2017WinterShotcreteEMag
To see the actual publication please follow the link above