PSI - Issue 78

Leonardo Casali et al. / Procedia Structural Integrity 78 (2026) 1269–1276

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Table 2. Limit values of vertical deformation of floors and roofs - Statics. Floor section Floor elements in the operating floors of the PM3 building (excluding the area for actuating motors and other equipment, which will be defined by the PM supplier).

Maximum vertical deformation of floor elements

L/500

Roof elements

L/250 L/600

Overhead crane, vertical deformation of runway beam

The traditional schemes of prefabricated buildings characterized by hinged beam-column nodes are characterized by high deformability and generally do not allow the stringent limitations on permitted deformations to be respected, therefore measures capable of reducing the deformability of the structure must be provided. The problem does not only arise with respect to service loads, but also with respect to seismic actions. In the following the measures adopted for the examined building are presented. 3. Connections between elements within prefabricated concrete structure The main columns of the PM3 Paper Machine building and the auxiliary building were considered to be fixed and embedded in the foundation, while the intermediate joints of the beams along the columns were considered to be pinned. This configuration does not allow to meet the requirements concerning the limitations of lateral deformations previously mentioned with reference to the service load, nor the limitations of the story drifts associated with seismic actions. A stiffening of the structural scheme was then required and different solutions were applied with reference to the two main directions, transversal and longitudinal, of the structure. 3.1. Transversal stiffening With reference to Block A, in order to meet the requirements for horizontal deformability of PM3 buildings due to the actions of wind and the braking of overhead travelling cranes, many of the connections between the main beams in transverse direction at level +7.00 and the building columns have had to be considered semi-fixed (continuous with assigned stiffness) in order to have a structure that was as rigid as required. Similarly, other joints have been made continuous at levels +18,50 and +20,50. The other connections between floor beams and columns at mezzanine level +13.50 and at roof were left articulated. The stiffening of the nodes is achieved by inserting at the beam-column joints of the structure, devices consisting of steel "crescent"-shaped element as shown in Fig. 4, also called "sickle". Columns and beams are equipped with the necessary arrangements to install the connecting devices: the devices have been designed and located in such a way to guarantee the possibility of being inspected and, eventually, replaced by an easy access.

Fig. 4"Crescent moon" elements used at the beam-column connections.