Σχεδιασμός σύμμικτου κτιρίου εμπορικού κέντρου με αίθριο

Abstract

Αντικείμενο της παρούσας μεταπτυχιακής εργασίας είναι η διαδικασία σχεδιασμού και διαστασιολόγησης ενός μεγάλου έργου με σύμμικτο φέροντα οργανισμό από χάλυβα και οπλισμένο σκυρόδεμα, με χρήση ενός εμπορικά διατιθέμενου προγράμματος. Το κτίριο που επιλέχθηκε προς μελέτη είναι ένα κτίριο μεγάλων ανοιγμάτων για εμπορική χρήση με έναν υπόγειο χώρο στάθμευσης και αίθριο. Οι διαστάσεις του κτιρίου είναι 56 m x 72 m.

Η ανάλυση και η διαστασιολόγηση της κατασκευής πραγματοποιήθηκε με βάση τους Ευρωκώδικες και τον Ελληνικό Αντισεισμικό Κανονισμό. Πιο συγκεκριμένα χρησιμοποιήθηκαν οι ακόλουθοι κανονισμοί: - Ευρωκώδικας 1: Φορτία χιονιού (Μέρος 2-3), Φορτία ανέμου (Μέρος 2-4) - Ευρωκώδικας 3: Σχεδιασμός μεταλλικών κατασκευών (Μέρος 1-1) - Ευρωκώδικας 4: Σχεδιασμός σύμμικτων κατασκευών από χάλυβα και σκυρόδεμα (Μέρος 1-1) - Ελληνικός Αντισεισμικός Κανονισμός 2000. Η επίλυση του κτιρίου έγινε με το πρόγραμμα ανάλυσης και διαστασιολόγησης Sofistik.

Στο πρώτο κεφάλαιο παρουσιάζεται το κτίριο, αναλύεται η αρχιτεκτονική και η κατασκευή του έργου και παρατίθενται στοιχεία σχετικά με την ανέγερσή του. Στο τέλος του κεφαλαίου περιγράφεται το πρόγραμμα ανάλυσης και διαστασιολόγησης Sofistik.

Στο δεύτερο κεφάλαιο γίνεται εκτενής αναφορά στον προσδιορισμό των φορτίων που καταπονούν την κατασκευή, ενώ παρατίθενται και αντίστοιχα αποσπάσματα των κανονισμών βάσει των οποίων προέκυψαν τα επιβαλλόμενα φορτία.

Στο τρίτο κεφάλαιο περιγράφονται οι συνδυασμοί των δράσεων στην οριακή κατάσταση αστοχίας και λειτουργικότητας όπως απαιτείται από τον Ευρωκώδικα 1.

Στο τέταρτο κεφάλαιο παρουσιάζονται οι σεισμικές δράσεις όπως περιγράφονται από τον Ελληνικό Αντισεισμικό Κανονισμό, καθώς και οι απαιτούμενες ιδιομορφές για την ανάλυση του κτιρίου.

Στο πέμπτο και έκτο κεφάλαιο διατυπώνονται οι απαιτούμενοι έλεγχοι σύμφωνα με τους Ευρωκώδικες 3 και 4, παρουσιάζονται τα αποτελέσματα της ανάλυσης όπως προέκυψαν από τους υπολογισμούς με τη βοήθεια του προγράμματος ελέγχου μελών του Sofistik, και επιβεβαιώνεται η επάρκεια των διατομών έναντι των εντατικών καταστάσεων στις οποίες υποβάλλονται.

Τέλος, στο έβδομο κεφάλαιο παρουσιάζονται τα αποτελέσματα της εν λόγω εργασίας.

The field of this study is the design of a large project with composite steel and concrete structure, using a commercially available program. The building chosen for study is a large scale building for commercial use with underground parking and an atrium in the center. The dimensions of the building are 56 m x 72 m.

The analysis and design of the structure are based on the Eurocodes and the Hellenic Code for Earthquake Resistance of Structures. More specifically, the following regulations were used: • Eurocode 1 : Basis of design and actions on structures, • Eurocode 3 : Design of steel structures, • Eurocode 4 : Design of composite steel and concrete structures, • Hellenic Code for Earthquake Resistance of Structures.

Eurocode 1 provides design guidance and actions for the structural design of buildings and civil engineering works including some geotechnical aspects on the following subjects: • Densities of construction materials and stored materials, • Self-weight of construction works, • Imposed loads for buildings. Furthermore, in reference to Eurocode 1, the Part 1-3 was used, which is about the Snow loads and the Part 1-4, which is about Wind actions.

Eurocode 3 applies to the design of buildings and civil engineering works in steel. It complies with the principles and requirements for the safety and serviceability of structures. The main purpose of Eurocode 3 is to maintain requirements for resistance, serviceability, durability and fire resistance of steel structures. Depending upon the type of action affecting durability and the design working life steel structures should be: • designed against corrosion by means of: • suitable surface protection, • the use of weathering steel, • the use of stainless steel, • detailed for sufficient fatigue life, • designed for wearing, • designed for accidental actions, • inspected and maintained.

Eurocode 4 applies to the design of composite structures and members for buildings and civil engineering works. The composite structures and members are made of structural steel and reinforced or prestressed concrete, which are connected together to resist loads. This Eurocode’s only purpose is to sustain the requirements for resistance, serviceability and durability of structures. Other requirements, e.g. concerning thermal or sound insulation, are not considered. Part 1.1 of Eurocode 4 gives a general basis for the design of composite structures and members for buildings and civil engineering works. In addition, Part 1.1 gives detailed rules for composite slabs, beams, columns and frames, which are mostly applicable to ordinary buildings. The applicability of these rules may be limited, for practical reasons or due to simplifications; their use and any limits of applicability are explained in the text when required.

Hellenic Code for Earthquake Resistance of Structures applies to the design and construction of buildings and civil engineering works in seismic regions. Its purpose is to ensure, that in the event of earthquakes: • human lives are protected, • damage is limited, • structures important for civil protection remain operational. Due to the random nature of the seismic events and the limited resources available to counter their effects, any outcomes calculated are measured in terms of probability only. The extent of the probable protection that can be provided to different categories of buildings is a matter of optimal allocation of resources and therefore will vary from country to country, depending on the relative importance of the seismic risk with respect to various risks and on current global economic resources.

The analysis of the building was made up with the SOFiSTiK AG engineering software.

The building consists of one basement and three floors. • At level -1, a basement of 4.032,00 m2, throughout the coverage of the building. Some areas are used as parking spaces and others as storage areas for the equipment and engineering facilities of the building. At this level, one has access via ramps and elevators, and can be driven to the main areas of the building via escalators and elevators. • At levels of 0, 1 and 2, there are stores such as clothing and footwear stores, dining areas, utility rooms and main places of public gathering.

In this thesis, the following are presented: • first chapter: the architecture and the construction of the project, as well as the engineering software SOFiSTiK AG with its subroutines, • second chapter: a detailed report on the identification of the action stresses on the structure and an analytical calculation of all the characteristic values of imposed loads based on the Eurocode 1, • third chapter: the combinations of actions to Ultimate Limit States and Serviceability Limit States as required by Eurocodes 1 and 3 and also the maximum displacement for each direction, • fourth chapter: the seismic actions that are imposed on the structure during an earthquake as they are described by the Hellenic Code for Earthquake Resistance of Structures and the Eigenforms required for the seismic analysis of the building, plus the combinations of the seismic action with other actions, • fifth and sixth chapter: the required tests according to Eurocodes 3 and 4, the results of the analysis as derived from the results of the program, and the confirmation of the adequacy of the cross sections versus intensive situations that incurred, • seventh chapter: the results of this thesis.

The following assumptions apply: • Structures are designed by appropriately qualified and experienced personnel, • adequate supervision and quality systems are provided during execution of the work, i.e. in design offices, factories, plants and on site, • construction is carried out by personnel having the appropriate skills and experience, • the construction materials and products are used as specified in the Eurocodes or in the relevant material or product specifications, • the structure will be adequately maintained, • the structure will be used in accordance with the design brief.