"DIGIT" carries out calculations for reconstruction of a ski jump on Sparrow Hills

On October 18, 2018 the "Center of Engineering and Physical Calculations and Analysis" (JSC TSIFRA) company announced that Big a ski jump on Sparrow Hills undergoes reconstruction: the geometry of a profile of a springboard and the engineering systems will be changed according to the updated requirements of the International Ski Federation that will allow to hold high-class international competitions.

At redesign of a springboard will consider action of hurricanes. Taking into account a difficult relief of Sparrow Hills, the main factor of possible wrest of piles of a springboard is wind. A wind load makes 50% of efforts in piles. To define conditions of durability of construction and to provide operation of the sporting venue at the high level, the St. Petersburg specialists by request of the projecting POLYTECHNIC UNIVERSITY-UIMP-XXI CENTURY LLC company executed calculation of a wind load of JSC TSIFRA by methods of computing aerodynamics.

To analyze durability and reliability of a designed structure under the influence of wind, specialists of "The center of engineering and physical calculations and the analysis" constructed computer model of a springboard and a surrounding relief. They defined distribution of a wind load to surfaces of a springboard by mathematical modeling and executed space visualization of the flow which is flowing round a springboard.

"We simulated the movement of wind in three potentially dangerous directions: east, western and northern. Defined that wind pressure upon the springboard body at the level of a tower and the highest sections of construction reaches 0.5 KPA. Considering the area of a facade of a construction and its height, such wind pressure causes the significant pulling-out efforts reaching 50 tons in columns. The worst case of the running flow for a springboard is side Eastwind – it gives the maximum overturning moment and causes the maximum horizontal movements of a flying part. Designers will use the received pictures of a wind field in different zones of a springboard for further settlement justification and the analysis of structural elements". PhD in Technological Sciences Dmitry Sergeyevich Mikhalyuk, CEO of JSC TSIFRA

Designers of a constructive and architectural part of a springboard from POLYTECHNIC UNIVERSITY-UIMP-XXI CENTURY LLC took fields of wind pressure upon the springboard body for a basis when calculating durability of metal construction and the pile base. At the same time differences between the actual wind pressure received from calculation and the conditions described in the recommendations of normative and technical documents about design are detected. These differences concern, first of all, intensity of wind pressure at the edges of a construction. Their accounting gives higher values of efforts in columns, than according to requirements of standard regulations.

"Calculation of a wind load by methods of computing aerodynamics allowed to specify significantly the wind pressure upon a construction facade, to receive more realistic efforts in reference elements and to provide big reliability and durability of a springboard in general". PhD in Technological Sciences Dmitry Valeryevich Klimshin, technical director of POLYTECHNIC UNIVERSITY-UIMP-XXI CENTURY LLC

To stabilize a roll of a construction and to reduce the pulling-out efforts to piles, the first floor of a springboard is executed of concrete with columns of 1200х1200 mm and buried in soil at 5 meters. At the expense of the mass of the first floor the lack of the pulling-out efforts on a pile field is reached that allows to use piles also more optimum.

For calculation of wind pressure specialists used program system of Ansys Fluent, and applied the settlement SCAD 21.1 complex to design. As designers noted, the main features of a ski jump which are required to be considered in terms of design is, first, a critical role of a wind load in efforts on piles of the base of a construction, secondly, emergence under the influence of wind of a bend of a zone of acceleration of skiers in a flying part of a springboard, thirdly, influence of wind on fastenings of finishing and elements of a facade of a springboard.