Hi, this is Arthur again. We went to a privately owned site in an upscale neighborhood on Tuesday. The whole project actually contains two individual houses. One of them just finished up with the foundation. The other one is preparing for pouring the beam on the second floor. In this blog, I will continue to compare the different methods being used for the construction management and engineering in practice within different countries.
First, I want to introduce the owner of the company, Marinski, and talk about what he does differently in the field of construction management (CM) from the States and China. Marinski has a high criterion of his project, dedicate in the projects he does and takes care of his employees. He would do those projects he likes. He loves small size crew of 60 including the construction workers and only takes few projects at same time. He trains each worker by himself and keeps them as full-time employees. He offers them a one-month break during the new year on top of their annual vacation. Similar to the States, nobody works during the weekends. It’s different in China, construction worker usually has to work every day except few days’ vacation for the Chinese New Year. Employees in Marinski Ltd. get paid well. They get paid for each stage they finished as an incentive. We would never have that in the States. Marinski also invented his own management software to tracking the materials and equipment in the warehouse. Bulgaria does not yet have a reliable CM software, such as the Procore we often use in the States.
In the construction site, safety is always the first concern. However, in the Marinski Ltd, they only had one accident in the past ten years. One the worker got into a car accident on the way back home. In Bulgaria, the company takes all the responsibilities for anything happens to the employees during the transportation to the work and back home. The company also provides steel-toe shoes and hard hats, as well as daily safety instructions. When the temperature rises up to 35c any exterior constructions has to stop. Unlike in the States, we would continue the construction but offer more breaks during the work. However, the staff work with the concrete did not have their mask on, which is required in the States. Also, they did not have the protect from the height, which is required in China. We would have a decorated wall covered the construction site, and cover the building with a special polymer net. Not only for the protection of the construction workers falling down, but also prevent anything drops from the height to hit anyone else.
Now, I will introduce the project we visited. The owner of the house want wants the Marinski Ltd to help him building two additional houses for his child on his land. Similar to the most Europian and Asian Country, it is really common in Bulgaria, that parents would take care of their children’s houses and they usually live close to the family, which is not typical in the States. The project involves massive concrete and brickworks, which differ from the typical wooden structure from the northern America. One of the reasons is the typical timber produced in Bulgaria is too soft to support the loads.
One interesting feature is that the project was enclosed by planks with dozens of nails on it. Those nails were not placed randomly. They represent the ground level and the orientation of the columns. Those magic nails were placed by geotechnical engineer and surveyor after excavation. They would connect each two pairs of nails by orange wire, and each cross of two wires are the center of a column. Therefore, the positioning and leveling of the foundation and columns are easily done. In China, survey usually would come after excavation and label the center of the piles. The contractor would trust the drillers do the work, most of the time the error is negligible. In the States, Caterpillar invented Terrian™ and ACCUGRADE™ systems for drilling and excavation. It using GPS, GNSS, laser and ATS technologies to precisely control the process and minimize the degree of accuracy, meanwhile increases in productivity up to 40 percent.
Addition to the magic nail they used, they also have some magic joint connect the steel forms for the foundation. There are four joint inserted between two feet long steel plates and joined by huge bolts. Therefor the form would firmly connected and minimize any displacement or potential failure during the vibration process. The joint will leave inside of the concrete, and the workers will bend it to the side and cover with another layer of stucco.
EU has very strict regulations on the new buildings under constructions. For the exterior walls, the minimum width is 35 cm which is equivalent to 14 inches. And the interior wall has to be wider than 15 cm. Marinski recommended to his client use thicker bricks for the interior too for the best thermal insulation. The concrete they used is C20_25, which has a bearing capacity of 3600 Psi. That is similar to what we use in the States.
Overall, the Marinski Ltd does a great job in the construction. Especially, on the safety and some unique construction methods they used are practical in the States and China, such as the magic nail. I would like to implement those into my future career