Selective demolition of a complex of buildings used as a slaughterhouse

In 2021 we were entrusted by ABS Acciaierie Bertoli Safau with the remediation of a 40,000 square meter lot adjacent to their plant in the municipality of Pavia di Udine, where a complex of buildings was present. The purpose was to be able to use it for the construction of a new scrap yard equipped with a shearing plant for the preparation of metals ready for the furnace.

It was a complex consisting of a set of buildings built in the early 2000s to house a slaughterhouse that was never put into operation.

The buildings had an empty to full volume of about 28,000 cubic meters and the various rooms were strongly insulated, mostly being refrigerated cells. The project entrusted to GESTECO SPA consisted of the demolition of all structures, including the foundations, located on the site.

Our technicians, after an initial site visit, verified that all the buildings needed to be cleared of furniture, mobile equipment, and supplies that still occupied the premises. Samples of materials referring to sheathing, insulation, pipes, and others were taken and sent to our laboratory to verify the presence of asbestos and for subsequent recovery and/or disposal activities. Additionally, the structures were evaluated, confirming the constituent elements: it was immediately clear that insulation elements were present everywhere, both in the perimeter walls and internal partitions, as well as in the roofs and underneath the floors; 70% of the building's structure was intended for meat preservation and, therefore, was divided into multiple rooms and refrigerated cells.

The slaughterhouse's equipment was present as if it were already in operation. It was therefore necessary to initially proceed with the clearance of the premises with the sorting of different types of waste and their disposal or recovery at authorized facilities.
The demolition had to involve, as it progressed, the separate management of metallic equipment such as overhead meat transport corridors, machinery, etc.

The main challenge was expected in the sorting of the various materials constituting the buildings and the various types of insulation in order to ensure separate management by type for the potential recovery and consequent cost reduction. Excavators equipped with handling claws and hydraulic demolition shears and wheeled loaders were involved in the removal of equipment and internal partitions, as well as the demolition of the structures.

Ground personnel supported all activities to optimize the separation and management of different types of materials, ensuring the cleanliness and necessary order for the correct waste management.
Special techniques such as vacuuming and bagging of polystyrene, which constituted the internal insulation of all precast panels and floor slabs, were also used.

The client requested the recovery of some "demolition aggregates" (mostly concrete) to reuse it after treatment for the site's restoration.

Bureaucratic requirements related

Gesteco prepared the necessary paperwork for the recovery of inert materials on-site, informing the competent local authorities of the inert waste recovery campaign pursuant to art. 208 paragraph 15, Legislative Decree 152/2006 (Environmental Consolidation Act) using an authorized crushing plant, describing the treatment process applied, the description of the waste managed with the respective quantities and recovery operations, and the description of the environmental impacts for the execution of the activities, as well as the characteristics of the recovered materials (End of Waste).

The first aspect addressed was the STRIP-OUT activity of the various rooms, separating the different types of material and coding them in various containers for subsequent disposal or recovery.

We started with the demolition activity using a hydraulic clamp placed on the tracked excavators; while a third excavator, assisted with a handling bucket, selected different concrete material to be destined for subsequent disposal/recovery.

The primary demolition took place in sequence from top to bottom removing the metal parts and disintegrating the reinforced concrete structures into small blocks, avoiding sudden collapses of significant size portions.
In this phase, in an area dedicated to their crushing using a secondary demolition clamp to de-iron and separate them from the internal insulation, polystyrene will be separated using two blowers and manually bagged inside big bags for subsequent disposal.

The demolition sequence of the load-bearing structures followed the following progress portions:

• Covering tiles - Beams (internal partitions)
• Pillars or load-bearing walls
• Floor slabs
• Beams (internal partitions)
• Pillars or load-bearing walls
• Floors
• Foundations. 

The bituminous membrane on the covering tiles and flat roof was removed as the demolition progressed by means of mechanical equipment and further selection on the ground with mechanical means and manual intervention of ground assistance personnel: other types of materials intercepted by the demolition were managed similarly. Once part of the covering or floor slabs (with already previously demolished infill walls) were removed, where there were insulated sandwich panels of various thicknesses, they were managed and removed with the support of an excavator equipped with a handling clamp that accurately removed them in portions and then placed them in containers previously prepared for this purpose.

The excavator followed the demolition phases to manage the various types of materials not attributable to aggregates, selecting and placing them in containers divided by type to then be disposed of in suitable plants.

The demolition of the foundations was carried out using a demolition hammer mounted on the excavator or with the use of hydraulic demolition shears for continuous foundations (connecting beams) once the soil had been moved in their vicinity to make them free and visible. The reinforced concrete blocks resulting from the demolitions will be demagnetized with an excavator equipped with a crushing clamp and, together with other aggregates (concrete, bricks, tiles, etc.), they will be loaded and transported to an area dedicated to the subsequent crushing to be carried out with an authorized mobile crusher to obtain MPS with a size of 0/90 mm, to be stocked in piles for use on-site for the construction of embankments and backfilling.

The demolition activity involved an average of 7/8 man-days and 4/5 operating machines per day.

To separate the different insulating materials, special techniques such as the aspiration and bagging of the internal polystyrene of the prefabricated panels and slabs have been used. The materials not subjected to crushing (reinforcements and metal structures, metal fixtures and glass) have been separated, accumulated in suitable areas and collected in containers. The operation was satisfactory and the criticality of the possible presence of polystyrene in the obtained MPS, attributable to the insulation of slabs and prefabricated panels, was averted by the good practices adopted for the aspiration and bagging of polystyrene, ensuring a material free from this unwanted fraction.

The campaign for the crushing of the demolished material was then activated, carried out by means of a mobile plant, for the on-site recovery of the obtained raw materials (MPS) in suitable sizes for reuse on-site for the construction of embankments and filling activities.