GOMACO World Index --- GOMACO World 33.1 - February 2005


Finishing A Canal With A 50-Year History




Studies to create a great irrigation project through the Beira Interior region in the country of Portugal have been conducted since the 1950s. The project would consist of creating a primary irrigation network with a main concrete trapezoidal canal. A secondary distribution network would be made up of a series of pipes with water for the irrigation network supplied by dams on the Meimoa and Sabugal rivers.

The project became a reality and construction of the 9.3 mile (15 km) canal began. Mota Engil Engenharia, a contractor based out of Porto, Portugal, is the main contractor for the construction of the second phase of the Monte do Bispo Canal and reservoir near Belmonte, Portugal.

Mota knew they wanted a cylinder finisher that could complete the three-sided canal in one pass. They turned to GOMACO and their distributor in Portugal, Auto Sueco Lda, to help them determine which machine would be best for their canal project.

“The trapezoidal section of the canal was designed to have a capacity for 8101 to 9688 yd3 per second (6194 to 7407 m3/s) of water flow,” Jorge Balsemao, mechanical engineer and equipment director for Mota, said. “A wall slope construction of 1.5 : 1 was designed in order to ensure slope stability and guarantee an appropriate concrete cover to avoid concrete leaks and segregation. It also allows the placing of concrete by a mechanical means.”

The canal had the added challenge of 70 radii.

“The canal alignment was designed with consideration of the total amount of earthwork and excavation so the radii were necessary,” Balsemao said. “The radii of the canal were calculated with consideration of the topographic and geo-technical conditions to guarantee the best flow of water on the project.”

The inside curve of the radii varied between 82 to 328 feet (25 m to 100 m). They needed a paver that could navigate and finish through the project’s radii.

Mota chose the GOMACO CP-650-S canal paver with a Spanit® work bridge and RC Conveyor for placing concrete in front of the finisher.

After approximately 850,163 yd3 (650,000 m3) of earth was excavated and another 287,748 yd3 (220,000 m3) of fill material was put back in, paving on the canal began.

Mota’s CP-650 is track mounted and runs on stringline instead of rails. Grade and steering control is maintained by an automated sensoring system that follows the stringline.

The canal has a 1.5 : 1 slope and is finished four inches (100 mm) thick. The walls vary between 6.4 to 7.4 feet (1.95 to 2.25 m) high with a bottom width of 6.6 feet (2 m).

Concrete was supplied by a batch plant 60 minutes away from the project. Six ready-mix trucks with a hauling capacity of 9.2 to 13.1 yd3 (7 to 10 m3) supplied concrete on a 45 minute cycle.




The project had 70 radii with inside curves between 82 to 328 feet (25 m to 100 m) the CP-650 navigated and finished through.



The CF-790 successfully completes a dry run in Portugal.




“We believe that single-pass canal finishing is a procedure that allows a very high quality of concrete finishing with very good production rates,” Balsemao. said.

Mota’s CP-650 utilizes two separate finishing cylinders and carriages with the GOMACO finishing system that aids in high production. The augers level the concrete that the RC Conveyor has placed on grade and the cylinders consolidate and finish the concrete, all in a single paving pass.

A Spanit work bridge that matches the canal’s profile follows the CP-650 and serves as both a finishing work bridge and crosswalk.

Mota’s work on the second phase of the canal has been a success. They’ve bid on and won the next phase of the canal and have once again contacted GOMACO for another cylinder finisher. GOMACO engineers went back to the drawing board to design the ultimate canal paver. Watch a future edition of GOMACO World magazine for a feature story on Mota’s new CF-790 canal paver.




The CP-650 finishes the three-sided canal in one pass. The canal had a slope of 1.5 :1 with a bottom width of 6.6 feet (2 m).



CP-650, RC Conveyor and Spanit work bridge

Mota has an RC Conveyor placing concrete on the grade in front of the CP-650 and a Spanit work bridge follows the finisher.




The new CF-790’s unique design allows the bottom frame to be partially disassembled and remaining slope frames and the finishing carriages can be winched up under the upper structure for ease in moving in and out of the canal or from one project to another.


CF-790 graphic

An engineering drawing illustrates the unique design of the new CF-790 slope and canal finisher.






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