POST-EARTHQUAKE INTERVENTIONS : PREVENTION AND SAFETY TECHNIQUES FACTORY BUILDINGS: THE MAIN FEATURES, THE Author:Anna Marzo Worki ng group: Aless andr a Gugliandolo Maurizio IndirliGiuseppe Marghella Maria-Anna Segreto INEFFICIENCIES AND THE SUITABLE INTERVENTIONS ACCORDING TO THE EUROPEAN REGULATIONS
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Distribution of the seismicity on the European territory
form the highest (red) to the lowest (bleu) seismic areas
The reduction of the seismicity from south to north due to the plates localization. The more seismic countries are located along the Italy is located on the plate limitation
The earthquakes occur along the plate perimeter, when they move
Panels-structure connections realized by steel anchorages
Regular opening
Claddings façades are very commonin industrial buildings. In these cases
it is very important to check the
fixing system to the buildingstructure taking into account thevertical force distributed on thesingle panel.The seismic action may beevaluated by considering a force
UNI ENV 1992-1-3 30-09-1995. Eurocode 2. Design of concrete structures . General rules and rules forbuildings
Connections
• Damage due to cyclic deformation in plastic field should be considered; the strength design of the connections should be reduced in order to
taken into account of seismic stress, if it is required;
•in case of panel-bearing structures both r.c. and welded joints effectiveness should be experimentally tested;
•beam-pillar connections should guarantee the matching of both vertical and horizontal displacements and the stress should be transferred by
means of mechanical devices;•it is consented the realization of a sliding support at one end of the beam, but the sliding surface should be more extended then the seismic
displacement required;
•in case of connection between non monolithic parts ad hoc design criteria should be considered (three types are possible);
•Pillar-horizontal elements connection should be fix (rigid or elastic) when the pillars are isostatic elements;
•In general, the connections between both structural and completion elements should be guarantee the transmission of both static and seismic
The main requirements for structural elements and connections
UNI ENV 1998-1-4 31-10-1999. Eurocodice 8 - Design of structures for earthquake resistance. Part 1: General
rules, seismic actions and rules for building.
stress in the safe side, therefore simply friction connections are not permitted.
Beams
•The beam width should be greater then 20 cm, while for small beams (namely “flat beams”) it should not exceed the pillar width, increased on
both sides by the half height of the same beam;
•The ratio between transversal dimension of the beam (width/height) should not exceed 0.25;
•Axes of both beam and pillars supported (namely “in false”) should be aligned; in addition the beams should have at least two supports (pillars or
shell); the shell can not be supported on beam or plate “in false”;
•The critic zones are extended to 1 or 1,5 times the beam height for slow ductility class or high ductility class, respectively. In case of beam which
supports “in false” pillars the critic zone should be extended for two times of the beam high, starting from the beam-pillar node in all cases.
Pillars
•The pillar transversal section should be grater then 25 cm, while for small beams it should not exceed the pillar width, increased on both sides by
the half height of the same beam.
•In addition, the codes provide same limitation about reinforcement, which are evaluated case by case.
FACTORY BUILDINGS: Reduction of the seismic vulnerability
It has been providing some suggestions for professional engineers, suitable to evaluate quickly seismic safety and set upreasonable anti-seismic strengthening interventions for simple-storey. Reinforced prestressed precast concrete construction,taking into account both the safeguard of human life and the recovery of serviceability conditions, saving machinery andequipment.
Guideline for both local and global interventions on factory buildings developed by Eurocode.
SLIDING SUPPORTS • Evaluation of the section features and of the related forks (reinforcement, transversal
sections, and so on ;• Realization of constraint elements, when any fork is present