http://hdl.handle.net/11728/10 Δημοσιεύσεις σε συνέδρια Sun, 05 Apr 2026 17:09:13 GMT 2026-04-05T17:09:13Z http://hdl.handle.net/11728/13234 Influence of GGBS and SRA on Early-Age Shrinkage Cracking Potential of Self-compacting Concrete: Insights from Capillary Pressure Jamali, Armin; Mendes, Joao; Nagaratnam, Brabha; Lim, Michael Shrinkage cracking is a prevalent failure mode in concrete structures, particularly those with low volume-to-surface ratios, compromising durability and increasing maintenance costs. Early-age concrete is more prone to shrinkage cracking due to insufficient strength development. Capillary pressure is recognized as the primary driver of shrinkage in concrete; however, conventional sensors can only measure capillary pressure up to 100 kPa for approximately seven hours post-casting, hindering a comprehensive understanding of the relationship between capillary pressure evolution, early-age shrinkage, and cracking potential. This study employs a novel high-capacity tensiometer (HCT) capable of monitoring capillary pressure in concrete up to 2000 kPa, thereby extending measurement capabilities. The effects of ground granulated blast furnace slag (GGBS) and shrinkage-reducing admixture (SRA) on capillary pressure evolution and shrinkage cracking potential were investigated. An extensive experimental program, including measurements of settlement, free and restrained shrinkage, elastic modulus, and tensile strength, was conducted alongside capillary pressure monitoring. Results show that significant shrinkage occurs during initial and final setting times when concrete remains in the plastic phase, with minimal capillary pressure evolution. With further development of capillary pressure, cracking was observed during the semi-plastic phase due to a marked reduction in strain capacity of concrete. The findings also indicate that although GGBS replacement reduces capillary pressure evolution, it is not an effective strategy for mitigating shrinkage cracking due to concurrent reductions in tensile strength. Notably, the effectiveness of SRA is inversely related to GGBS content, necessitating careful consideration in its application. Sat, 30 Aug 2025 00:00:00 GMT http://hdl.handle.net/11728/13234 2025-08-30T00:00:00Z http://hdl.handle.net/11728/12329 Numerical aspects of incremental dynamic analysis for the retrofitting of existing industrial steel building utilizing SSCD dampers Bellos, John; Bakas, Nikolaos; Castiglioni, Carlo In this work, the nonlinear analysis of an existing industrial steel structure (Sodium building), and its retrofitting using SSCD dampers is demonstrated. Specific numerical complications of incremental dynamic (IDA) and pushover analyses as well as their resolution are presented. In particular, the modelling of a flag shaped, self-centering steel device (SSCD) exhibiting re-centering and recovery, as well as it’s connection to the structural frames, the results of IDAs in comparison with the results of the Pushover analysis, the ability of IDA to capture nonlinear behavior for high accelerations where pushover stops, the optimal values of dampers stiffness and strength in order to maximize the energy dissipation within the structure, the comparison of the structural performance before and after retrofitting, as well as the association between the re-centering β-factor and capacity curves, are analytically demonstrated. Additionally, the effect of the variation of the dampers positions along building’s height as well as the effect of the damper to the capacity curves is discussed. Sun, 01 Jan 2017 00:00:00 GMT http://hdl.handle.net/11728/12329 2017-01-01T00:00:00Z http://hdl.handle.net/11728/11797 Formal Strategies of Familiarization and de-Familiarization Dova, Evanthia In the first-year design studios, discussions on form tend to be avoided; for those un-initiated in architectural thinking, forms may easily be associated with stylistic or aesthetic pursuits, far removed from the conceptual rigor, functional connections, technical knowledge or representational dexterities that incoming students are expected to comprehend. Yet though idea and sequence, visuals and structure may take the stage, it is through forms that they are investigated; it is forms that can be put on paper or built in models or coded on screens. Forms are the perceptible product of teaching, the readily analyzable lab object, the tool with which we interpret environment, use and materiality. This paper discusses the utilization of formal strategies by the two design studios taught in the first year of the NUP Program in Architecture. The first-semester studio, based on a simplified version of the well-known nine-square grid problem, employs a kit-of parts strategy in order to exploit the tactile materiality of toys and the structural consistency of games. The second-semester studio, narrowing its focus on issues of dwelling, meshes narrative with visualization in order to examine the conventions of everyday spaces in the city and at home. In both, experimenting with form lends itself as a method of developing representational and communication skills, as a technique of understanding and exploring spatial relationships, and as an instrument for questioning the dominant perceptions of ‘ordinary’ and ‘extra-ordinary’. Playing with form offers a means to de-familiarize students with their accustomed ways of learning and with what they expect to learn, and to familiarize them with the seldom linear, often strenuous, but always exciting route of transforming an idea into space. Mon, 01 Mar 2021 00:00:00 GMT http://hdl.handle.net/11728/11797 2021-03-01T00:00:00Z http://hdl.handle.net/11728/10503 Διαχείριση, Περιβαλλοντική Προστασία, Αισθητική και Οικολογική Ανάδειξη των Περιαστικών Δασών Δράμας, Λίμνης και Ελασσόνας Zigkiris, S.; Ftika, Z.; Konstantinidou, El.; Georgi, Neratzia Julia Η ικανοποίηση της συνεχούς ζήτησης αναψυχής στο περιαστικό δάσος προϋποθέτει την διαχείριση του χώρου κατάλληλα ώστε αφενός μεν να παρέχει καλύτερες υπηρεσίες στους επισκέπτες, και αφετέρου να προστατευθεί από την υπερβολική και κακή χρήση του από τους επισκέπτες. Με την παρούσα εργασία διερευνάται και αναλύεται η υφιστάμενη κατάσταση των περιαστικών δασών Δράμας, Λίμνης και Ελασσόνας και προτείνεται η ενδεδειγμένη μελλοντική μεθοδολογία διαχείρισης των. Οι απόψεις των κατοίκων αποτυπώνονται στην πρωτογενή έρευνα με τη χρήση ερωτηματολογίου (προσωπικής συνέντευξης). Τα αποτελέσματα επικεντρώνονται, ανεξάρτητα από την περιοχή, στον πολλαπλό ρόλο που διαδραματίζουν τα περιαστικά δάση για τις αστικές και ημιαστικές περιοχές. Η ένταξη των περιαστικών δασών και προπάντων του αστικού πράσινου ως βασικών στοιχείων χωροταξίας και πολεοδομικής ανασυγκρότησης των μεγάλων αλλά και μικρών αστικών κέντρων είναι το μέσο που θα δημιουργήσει ευνοϊκές προϋποθέσεις για μελλοντική αναβάθμιση των περιαστικών δασών, προκειμένου να επιτελείται επαρκώς ο σύγχρονος τριπλός παραγωγικός, οικολογικός και ταυτόχρονα κοινωνικός τους ρόλος. Thu, 01 Jan 2015 00:00:00 GMT http://hdl.handle.net/11728/10503 2015-01-01T00:00:00Z