CONSTRUCTIVE DESIGN OF WORKSHOP AND STRUCTURAL CALCULATIONS FOR THE REALIZATION OF THREE MULTI-STOREY METAL WALKWAYS ANNEXED TO THE CONSTRUCTION OF THE NEW DEPARTMENT OF EMERGENCY AND URGENCY AT THE POLYCLINIC OF SIENA

CLIENT: I.N.C.I. S.r.l.
SERVICES RENDERED: structural executive project
AMOUNT OF WORKS: 150.000€
BEGINNING/END OF WORKS: 2009-2010

PROJECT DESCRIPTION

In the context of the construction of the new Department of Emergency and Urgency at the Polyclinic of Siena, the work has provided the constructive design of the workshop and the structural calculation of the three multi-storey metal walkways necessary for the connection between the new building and the existing polyclinic. It has been decided to redefine all the profiles and the connection typologies realizing exclusively elements to be assembled with bolted unions. In order to be coherent with the executive design of the whole structural complex, the calculation method used was that of the Allowable Tensions according to the various D.M.del 1996.

1. North-East Footbridge
The structure is composed of four walkable decks with a reticular scheme on the horizontal plane and a non-passable roof deck. The walkable decks are completed with corrugated sheet metal slabs and collaborating casting but
without solidarization with metal beams. To the reticular decks is entrusted the static function of transferring the wind thrusts and, to a lesser extent, the seismic ones, in correspondence of the existing structural elements in reinforced concrete. A vertical structure with a mixed lattice-Vierendel static scheme acts mainly as a vertical constraint for all the decks. On the roof, lacking the constraint distrutture in c.c.a. to the plan, it is realized a system of bracing in the wall.
The connection of the columns to the bottom structures is made by means of base plate and anchor bolts. The walkway is released from the existing polyclinic building by means of seismic joints while the anchorage to the floors between the decks and the new building is made with heavy chemical systems.

2. North-West footbridge [3S]
The structural conception of the work foresees a reticular prismatic solid with quadrilateral section, anchored to two reinforced concrete partitions from which two rectangular section truss brackets project. The pedestrian deck is the lower one while the upper deck has only a covering function, both decks have a reticular structure. The floor does not cooperate with the metal beams. The walkway is free from the buildings under construction and existing through seismic joints of appropriate thickness in order to avoid hammering phenomena. The connection of the columns of the prismatic solid to the underlying reinforced concrete walls is made by means of a base plate and heavy duty chemical anchors.

3. North-West Footbridge [1S-2S]
The structure is composed of three reticular pedestrian decks on the horizontal plane, completed with corrugated sheet metal floors and concrete casting but without solidarization with the metal beams. The horizontal reticular decks have the static function of transferring the aeolian thrusts in correspondence of the existing reinforced concrete floors. The vertical loads are supported by wall trusses. A pair of round tube columns transfers part of the vertical loads to the foundations, while a round tube column and various heavy anchoring systems transfer all the remaining stresses of the metal structure to the existing reinforced concrete structures of the new building. The connection of the columns to the foundation structures is made by means of a base plate and anchor bolts. The connection of the deck beams to the existing reinforced concrete walls is made by means of heavy anchorage systems. The new structures are separated from those of the existing polyclinic by seismic joints.