
Restoration of cultural heritage

Restoration of cultural heritage
Restoration
of cultural
heritage

Construction is an activity that has left a lasting legacy to humanity that we have the opportunity to admire again and again.
Inspired by this very fact, ING-GRAD was founded as a construction company whose activities include specialized works comprised of: restoration and reconstruction of monumental heritage of exceptional historical and artistic significance.
In more than 35 years of work on the restoration and reconstruction of the monumental heritage, we have been using all the advantages of modern construction methods, but also applying unique knowledge based on the techniques, skills and recipes of old crafts.
Most buildings of cultural or architectural heritage are brick buildings built of stone or brick wall elements connected with mortar, usually found in poor condition due to their age and inadequate maintenance. Therefore, before the renovation and final arrangement, it is necessary to carry out constructive restoration. The complexity of the historical buildings restoration requires the incompatibility of traditional and new materials and respect for their original existence, which is why the use of reinforced concrete is not recommended. The most favourable technique for repairing and strengthening such constructions has proved to be injection, i.e., stabilizing and closing cracks in damaged walls by injecting special injection compounds, applying reinforced cement or epoxy coatings on one or both sides of the wall, and pre-tensioning the walls.
Roofs of monumental heritage buildings are usually wooden roofs with different types of covering, depending on the tradition of the climate in which the building is located. The reconstruction of such wooden roofs implies the replacement of individual elements or the complete structure with new wood, most often made of Slavonian oak or conifer, and the replacement of the covers.
The renovation and reconstruction of the building includes the renovation of the external facade, the execution of profiles and stone plastic, the production of wooden joinery and everything that includes the restoration of the historical appearance and original condition. It is done according to conservation guidelines, which is why the restoration and reconstruction of the building is longer and requires specific materials, works and methods of execution.
COM_INVESTITOR
Grad Zagreb
COM_KATEGORIJA
Public buildings
The building of the Petar Zrinski Elementary School in Krajiška 9, Zagreb was built in several stages from 1889 until today, and adapted on several occasions - with and without appropriate technical documentation. The basic corpus was constructed in 1889, after the great Zagreb earthquake. The school was expanded in 1922 to the height of two floors.
The next reconstruction began in 1956 and was completed in 1957, as designed by Krunoslav Vitanović. Two new wings were added to the school – the northeast and the southeast, both with basement, ground floor and two floors. The latest extension was made in 2001, when a sports hall with ancillary facilities was built and put into operation in 2005.
Following the devastating earthquake that hit Zagreb on March 22, 2020, inspection found that due to significant damage, the school building was unsafe for people to stay in or be in its immediate vicinity. In order to fully understand the extent of the damage, a geodetic survey of the verticality of the building was conducted and found a significant deviation in the verticality of the building, which indicates that the building was subject not only to horizontal but to vertical movement as well. The school building suffered other major damage as well:
Since the building has undergone floor plan changes throughout its history - transverse walls have been removed and the entrance changed, an intervention is necessary to strengthen them and achieve the required degree of seismic stability. In view of the above, concrete walls will be constructed along the entrance staircase, including the 2nd floor expansion. The existing load-bearing wall structure will be reinforced on the inside by adding 15 cm thick reinforced concrete walls. The walls will also be injected at the site of the cracks, while the inside of external walls will be thermally insulated with panels to achieve thermal protection. The inter-floor structure will be restored and strengthened by retaining the existing load-bearing structure of steel girders, and concreting a composite reinforced concrete slab 16 and 20 cm thick on top. Damaged steel girders will be replaced with new ones. The main staircase, significantly damaged in the earthquake, will be rebuilt as a replica of the existing staircase. New, lateral auxiliary staircases will be built from reinforced concrete to meet evacuation needs and fire safety requirements. The wooden roof will be replaced and the school finished and furnished for the safe and comfortable stay of schoolchildren.