Tunnel Sitiny Ing. Daniel Bukov OK TEAM Budatínska 31 851 05 Bratislava Slovakia Tel.: +421 63815362 Fax: +421 63537744 Contact: M. Daniel Bukov Email: [email protected] For twenty two years I have worked in the same company, always in connection with active structural design. In 1991, after velvet revolution, I started my own small firm, Ing. Daniel Bukov OK TEAM, as one of the many structural engineers in Slovakia. From the year 2001 on, I worked as a private structural designer mostly for conceptual structural design and calculation. During this time lot of things changed in professional life: efficiency of computers, operating systems and of course computers programs. In the beginning, I worked with computer programs NE-XX, SAPIV run under DOS later on with STRAP, STAAD and of course with ESA-Prima Win. Many of my structural analysis were performed for mechanical parts as pipes with large diameter, some technological projects including tanks silos and pressure vessels. In general The SITINY tunnel is erected in Bratislava as a part of the D2 highway which connects Bratislava with Brno. The project concerns two parallel tunnels, each with a width of approximately 8200 mm, a height of 8000 mm and a length of 1160 m. The main contractors for the tunnel are TAISEI, a Japanese Company, Skanska from Sweden and Banske stavby of Slovakia. The formwork of the tunnels has been fabricated and erected by the company PORTA s.r.o., Slovakia. The structural calculation was performed by Ing.Daniel Bukov OK TEAM Slovakia. The subject of the structural calculation was the calculation of various types of tunnel shuttering. One of them is presented in detail and the rest is presented by photos. The main task of the structural calculation was the check on the mechanical resistance of the tunnel formwork. The calculation was based on shop drawings and requirements of the customer. Input date Assembly drawings of the formwork. Requirements on the speed of pouring concrete and input on different levels. The speed limit for pouring of concrete is max 1,5 m /hour. The maximum level of the concrete between two sides is 1,0 m. Description of the structure The steel structure of the formwork is created from segments of 1980 mm width, which are reinforced by ribs. Ribs are created from bended steel plates, which are welded to the shell of formwork. Segments are connected in the cross section of the tunnel by pins. In longitudinal direction, segments are connected by special bolted connections. Connected segments are reinforced inside the formwork by a system of beams and struts. For transporting the formwork in longitudinal direction, a transportation carriage was designed. Transportation carriages consist from two parallel truss beams and two end cross frames. Cross frames are designed from box beams and longitudinal truss beams are designed from roll shape beams. All parts of the transportation carriage, excluded end frames, are parts of a cross reinforced tunnel formwork. The calculation of the outside shuttering was performed by the NEXIS/ ESA-Prima Win program. Assumptions of the calculation The loads of the formwork are considered according to STN 73 0035 with the parameters mentioned below: The speed of pouring concrete is max 1,5 m/hour (measured in the cross section of the tunnel) The maximal different concrete level of the opposite site is 1 m. The temperature of the fresh concrete is not less than 10° C The settlement of the fresh concrete cone is done according to STN 73 1312 max 60 mm The vibration compaction is 100 % The first layer of the concrete up to 800 m will be poured uniformly on both sides of the tunnel. On top of the cross beam in the space of the passage area of the formwork, the load may not exceed 1,5 kPa or 5kN/m of the beam Checks of the steel members are done according STN 73 14 01 Method of the structural calculation The structural calculation of the formwork has been done by the Finite Element Method (FEM). For the calculation of internal forces, 3D beams and a shell model were created. Separate load cases were created for each hour of pouring. The different level of the concrete was also considered. Supports were considered as stiff for the vertical direction and flexible for the horizontal direction. With regard to the flexibility of supports, effects of the friction between 158 Company Project Tunnel Sitiny - Tunnel Formwork structural calculation Ing. Daniel Bukov OK TEAM SCIA User Contest 2005 / Steel constructions 4 Categorie
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