MCR premiere in industrial sector in Dhaka

Peter Arndt    

As a consultant from the ECOSouth Network I visited the NGO DUS-Bangladesh in January of this year. On this occasion I had the opportunity to attend some meetings between DUS-Bangladesh and Diran Insulator Factory Ltd. Diran had planned to construct a factory and roof it with MCR-tiles (2500 square meters). As MCR technology is relatively unknown in Bangladesh, DUS-Bangladesh and ECOSouth were asked to build the roof. Together Prof. Nolasco Ruiz and I worked out the design of the building and the quotation.

 

Our task was to design the complete metal structure for this gigantic roof, as nobody in Bangladesh, and as far as I know anybody in the world, has yet covered such a big roof with Micro Concrete Roofing tiles. The task was difficult because we did not know the local customs of calculating the walls and we had to deal with different qualities of steel at different prices. Was it more economical to use heavier profiles of the lower grade steel or was it better to use small profiles of high grade imported steel, that was much more expensive? By e-mail we discussed those issues across continents, Dr. Iftekhar Ahmed, the architect in Bangladesh, Prof. Ruiz, the engineer in Cuba, and I, in Southern Africa.

Prof. Ruiz arrived in Dhaka at the beginning of June to supervise the building activities. First he discovered that some of the steel profiles included in the designs had vanished from the market, and then he was informed that heavy earthquakes do occur in Dhaka. Some changes in the drawings were necessary. On June 18 he could begin some physical activities with small entrepreneurs located around the factory. As this did not bring satisfactory results, on July 9 Diran took over the task of providing labor and machinery. Although construction was progressing, it became evident that it was not possible to finish the roof within the framework of Prof. Ruiz´s visas. As he could not extend his visas it was necessary that I return to Bangladesh.

I started work on August 12, when I visited the building site together with Nolasco and Modal Hakim of DU-Bangladesh. The basic structure was ready and nearly all the rafters were installed. The next steps were the installation of battens and water channels, then roofing and placing the ridge tiles.

I started work at the building site on August 17. During the first five working days delays developed because the welding process was not fast enough (we had to lay a total of 5,600 meters of battens). In the second week we recovered this delay by increasing the number of welders and welding machines. It was also necessary to include a second group of workers to lift the tiles up to the roof.

Tile makers from DUS-Bangladesh laid the tiles and masons who were hired on a daily basis installed the ridge. Some days there where as many as 75 people working. On Sunday, August 31, the roof was 99% complete, only lacking a few ridge tiles.

There was a high risk of breakage because of the long distances that the workers had to move about on the roof when the tiles were already placed, that is they walk on the tiles, and at times break some. The last three days there were around twenty people walking on the roof throughout the day, to build a ridge, to clean
the roof, to fix a corner, etc. The ladder was often far from where the job had to be done. It was an immense task, and could not be done all at once, so the workers needed to step over the tiles three to five times, sometimes up to a distance of 40m at the top. As the roof is high, the workers always needed helpers to lift up tiles, mortar, welding rods, etc.

Because the large number of workers walking on the tiles brings with it a higher risk of breakage, it might be worth considering 10mm tiles for such large roofs in the future.

I would like to thank all the people involved in this endeavor. Together we could resolve the problems that emerged along the way and complete the roof. Those of ECOSouth are pleased that MCR technology now also has reached the industrial sector.

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Consultants

Fernando Martirena
Cuban
Civil Engineer, PhD. Professor.
Spanish, English, German.
Research and investigation of materials, specifically alternative cement and cement products.

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