We have told the story of St. Petersburg Company “Kontinent” staking out the market of monolithic concrete works for transport construction before. You can find this article in our second edition of 2008 describing construction of piers at the Ust’-Luga transshipment terminal. Another tenant of the company’s efforts is the Morskoy Fasad project in St. Petersburg. The story is told by Oleg Nikulin, the Operations Director.
— What works have been brought to an end so far? What is being done at the moment?
— To this day we are done with monolithic concrete works on piled pier walls of the first, second, third pier. We carry on decking works, which should be finished by the New Year. This deadline also goes for sheetpile foundation strengthening, required to stabilize the sections within punch marks. This technology was proposed by “Lenmorniiproject” Design Institute: pipes should be driven in together with piles, tied to them by means of rods, filled with soil and poured. This will keep away oscillation of the pier wall. Local foundations here, just like elsewhere in St. Petersburg are unstable; the pier wall is stressed by waves and cumulic soil pressure. The construction of ramp for RO-RO ferries remains in prospect for the New Year. Currently, the design is in development. Construction and installation works will precede beginning from January. We also keep going the construction of above-ground structures and facilities.
— What works was this project specific of, that you had to master?
— Nothing new for us: deep foundations are quite widespread here. Nonetheless, bridge construction technology requires early civil works of the same complexity. Another thing is a vast number of foundation pits and truly hard conditions: the nature of cumulic soils. Backwater effect is considerable, that is why foundation pits are enclosed with steel sheet piles and are removed ring-by-ring. Sheet pile is delivered inside the “lock” and inflow water is bailed from the foundation pit. However, some equipment was completely new to us. The design specifications to avoid any type of extra pressure on soil made us use floating cranes to lower the pipes, what would have been impossible to do from the ground. For the “specific” part, all works we powered by diesel generators what significantly raised the cost of construction.
—What was difficult about foundation works?
— The main difficulty is with considerable pit dimensions, which require more sheet piles and supplementary steel structures for shoring, helping to withstand great earth thrust. For the above-ground facilities we used the technology called Fundex: socketing bored piles with detachable shoes. In particular, such piles were used for lighting poles foundations. Lighting poles are high steel supports subjected to heavy wind loads.
In order to resist the pulling force, each of such foundation needs nine bored piles.
— How many workers are tied to this job? How is the work organized?
— Currently we have 200 people working in two shifts: 24 hours a day. We work in rotations. One rotation takes a month; after that, a worker can take a road home. Most of our workers are from outside the city. Engineers and operators, quite the opposite, live here. So we prefer to entrust expensive equipment to the people working on a regular basis. In general we used to have up to 700 people involved at different projects, but still it is around 200 specialists who make the company’s core. Although double-shift mode requires a substitute for every engineer, it gives us many advantages. As much as we get the job done on a tight schedule, it is very important to avoid certain work cycles stretching beyond the shift’s time. For example, when there is a need to pour after hours, the second shift can take over it. Every site has a team of power engineers responsible to establish adequate lighting in work zones at night. All the required lighting equipment is usually in stock. Besides, every site has Production & Engineering Office making it off-line. At the moment “Kontinent” is represented at three projects: the second and third division is in Ust’-Luga and Vysotsk Coaling Harbor respectively. Yet a significant volume of works around the expansion of Tank Farm, Auxiliary Buildings and Facilities, is expected in Ust’-Luga.
— How massive are monolithic concrete structures you build?
— Here we talk about comparatively small structures and facilities: high-rise construction is inherent to artificially created territories. In the general sense, in refer to not tall buildings such as service facilities, accumulation ponds or energy supply units. Therefore, we feel pretty confident about monolithic concrete foundations. I should point out, that the first thing in the pier reinforcement scope was to set out the production of rebar strings from 1 b to 28 mm in diameter. Usually a string like this is welded with overlapping: two bars are coupled together with hand arc weld. But this method is not optimal due to being very labor intensive and largely depends on human factor in the matter of quality. And finally, overlapping presumes extra rebar consumption, what is relevant with this high cost of metal. The “puddle” method, with a U-shaped element to reinforce the joint, would be an even more challenging method. The design people offered to use a more progressive spot welding. The next step was to purchase a special machine and a powerful generator to weld them all butt-to-butt. We tested their tensile strength, and it turned out to be equal to that of a bar itself. It should be noted, that welding is performed by a small number of people familiar with this equipment. Usually it is three welders per shift, so the human factor influence shrinks significantly, not mentioning the deficit in welders. Such a welding machine is able to process rebars up to 41 mm.
— What is the volume of work you can do without exterior help?
— Pier decking in its integral capacity: strengthening sheet piles, concrete works, installation of mooring bollards, ladders for divers, and wheel guard devices. As for above-ground buildings and facilities, we build a case all the way from foundation to roof, and it is totally our domain as a contrary to finishing works and process structures, which we choose to leave for subcontractors. This is our first experience in civil construction using the monolithic technology, and still nothing difficult to tell about: we used to tackle much more complex tasks in bridge construction.
I would also add that some of these buildings and facilities were built by other contractors, who have failed for a variety of reasons, so now these facilities are given to us to work on. The best part is that besides bridge and hydraulic construction, and early civil works up to and including foundations, we have also gained a significant experience in civil construction. Although we do not plan start with housing works, we do not rule out this possibility, as you know, life can have slightly different plans for us. We always try to assess ourselves in other unconventional tasks.
For example, two transformer substations we build in Ust’-Luga, pretty big, with heavy foundations. For the first, we have signed an experienced subcontractor, but hope to build the next similar structures ourselves. Moreover, we have experience in building airport runways in Sheremetyevo, Khotilovo, Pulkovo: on a tight schedule we managed to set up production of 7,5 x 7,5 rebar cages and install them. In a word, we would like to continue with large projects where we have both experience and a good name.
— Can your “bridge skills” somehow encourage doing wrong things in civil construction? For example, using 36 mm rebars for walls?
— No, because our actions are guided by the detail design. Since these parameters are determined by design-people, they should be able to distinguish between a bearing wall and a bridge bearing.
— Do you plan to work at further away projects?
— There is a possibility of taking on some work in Sochi; we negotiate contracts in Samara, Tver. Yet, it is not clear what plans turn out practicable as the economic situation is complicated; many of our infrastructure projects were financed out of the corporate budget: even comparatively rich companies choose to take loans. The construction crisis is still to survive through, but we will do everything we can to keep our professional core: the best experts. It is not a secret that the best and highly-demanded always tend to leave in the time of crisis. So we are motivated to keep them. Anyway, if some of those projects are confirmed, we are likely to hire more people.
Federal structure and economy magazine No.16