KOLOS, the most significant award for construction in Croatia, presented to our very own Mirko Grošić for the open pit protection design for the Roxanich Heritage Wine Hotel and Wine Cellar project
At the 15th Days of the Croatian Chamber of Civil Engineers in Opatija, on June 17, 2021, the winners of the annual Kolos Awards were announced. The Kolos Awards are presented for special contribution to the Chamber and its promotion in the country and abroad, for contribution to the construction profession and for the development of the construction industry.
The Kolos Award for outstanding achievement in the profession of certified civil engineers in the category of geotechnics was presented to Mirko Grošić from Geotech d.o.o. from Rijeka, who led the open pit protection design for the Roxanich Heritage Wine Hotel and the Wine Cellar project. The geotechnical part of the project consisted of geotechnical investigation and testing, a geotechnical report, the main and detailed protection design and geotechnical supervision.
Location and construction
The new Roxanich Heritage Wine Hotel and wine cellar, an investment worth 10 million euros, sits at the site of an old cooperative cellar built in 1902, at the foothill of Motovun in Istra. The project included the construction of a hotel and a 5-storey wine cellar vertically excavated in an existing slope up to 23 m deep. The project was designed by the famous architect Idis Turato from Rijeka. The works started in 2017, and the hotel was opened in 2019.
Geotech applied the BIM approach in designing the main and detailed open pit protection, and as part of this approach a 3D model of the open pit was made. The BIM approach helps the interaction and cooperation with architects and structural designers be better and more precise. Clearer and more detailed visualization ensures easier detection of potential problematic situations, faster project design, as well as automatic calculation and tracking of quantities. This is one of the first applications of the BIM approach in geotechnical engineering (open pit protection) in the Republic of Croatia.
Open pit protection
Due to unfavorable geological structure at the site (weak rock easily weathered under the influence of water) and a height of 23 m, the excavation of the open pit was performed sectionally in vertical steps up to 2.5 m high. As the excavation progressed, open pit protection was conducted: systematic anchoring and protection with shotcrete 10 and 15 cm thick were carried out. These works also included the installation of self-drilling rock bolts with a load capacity of 300 and 675 kN, 4.5 to 15 m in length, on a grid of 2.5 x 2.5 m. A monitoring system consisting of 2 vertical inclinometers with a depth of 25 m was also installed.
The calculation of the open pit protection was carried out using the Plaxis 2D program. The calculation is available at the following link:
This project dealt with a complex open pit protection of significant height of 23 m in geologically demanding conditions, and everything was modeled using the BIM approach. This represents a step forward in design and the engineering profession and is an example of using new technologies in construction in accordance with global trends.