http://hdl.handle.net/11728/5 Σχολή Αρχιτεκτονικής και Γεωπεριβαλλοντικών Επιστημών 2026-03-22T14:14:45Z 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. 2025-08-30T00:00:00Z http://hdl.handle.net/11728/13233 Experimental investigation of the embedment strength of laminated veneer lumber (lvl) Vidanalage, Nuwan Padukka; Paraskeva, Themelina S; Kamperidis, Vasileios C Connections in timber structures play a vital role in the stiffness, strength and overall performance of the structure. Embedment properties are of paramount to the overall performance of bolted connections. This study experimentally investigates the performance of embedment strength of LVL manufactured from Nordic Spruce (Picea Abies), utilising 10mm steel dowels. A total of 50 embedment tests were conducted following the half-hole method, as specified in ASTM:D5764−97a. The tests had been performed considering 0°, 45°, and 90° load-to-grain angles, on edgewise orientation of the embedment properties and failure modes were analysed. The experimental embedment strengths were then compared to the respective characteristic embedment strengths proposed in Eurocode 5. While the characteristic embedment strength was 11% lower than the mean embedment strength for load parallel to grain, it overestimated the embedment strength by 9.2% and 7.2% for load-to-grain angles of 45°, and 90°, respectively. 2025-01-01T00:00:00Z http://hdl.handle.net/11728/13232 INVESTIGATION OF A COST-EFFICIENT RETROFITTING STRATEGY OF AN EXISTING REINFORCED CONCRETE BUILDING Ioannou, Anthos; Papamichael, Salomi; Bellos, John In the decades of 1950s, 1960s, 1970s, and 1980s most of the buildings in Cyprus, an island in the Mediterranean Sea which is located to a high seismicity region, were designed without seismic design criteria and detailing rules for structural systems ductility, including a lack of supervision and an inadequate quality control of construction works. Most of those buildings are now dealing with a variety of technical issues due to the irregularity in concrete strength, carbonation of the concrete and steel reinforcement and minimal use of transverse and longitudinal reinforcement of the structural elements. Consequently, it is crucial to identify and retrofit the structures that require seismic upgrading. This work presents a case study of an existing reinforced concrete building in Cyprus that was built in the 1980s and had one of its roof floor cantilevers fail. Firstly, this study focuses on identifying critical failures using nonlinear pushover static analysis, and secondly, it investigates different retrofitting strategies and identifies the most practical and cost-effective approach for seismic retrofitting. These approaches include retrofitting with combined infilled walls and concrete jacketing and combined brace-frame systems and steel jacketing for seismic integrity. 2024-07-01T00:00:00Z http://hdl.handle.net/11728/13231 SEISMIC ASSESSMENT AND INNOVATIVE STRENGTHENING OF CORRODED CANTILEVER STRUCTURES IN MULTI-STOREY BUILDINGS Ioannou, Anthos; Papamichael, Salomi; Genikomsou, Aikaterini S; Stylianidis, Panagiotis; Bellos, John The research aims to investigate the existing design standards KANEPE (2017) [1] and EN 1998-3 (2005) [2] regarding the seismic assessment of existing reinforced concrete structures through a real case study. Also, the current and applicable design standards together with the available strategies and methodologies for seismic retrofit of existing structures are presented in detail. In addition, the techniques and methods proposed to date for retrofitting reinforced concrete cantilever members such as balconies are analyzed. Through the real example, are presented: the operation of the reference building over the years, its existing conditions and the available architectural and structural engineering studies on the basis of which the build ing was constructed. In addition, the assessment methodology is described using the seismic assessment results of the existing building by identifying the critical structural elements with an advanced degree of damage aiming to explore innovative retrofitting methods, focusing on cantilever structural elements. The novel aspect of the proposed research project distin guishes it from similar studies by using an actual case study of an existing reinforced con crete structure that was constructed in Rush in the 1980s. As a result of aging, the structure's cantilever failed in a brittle manner. With regard to reinforced concrete cantilevers aging is sues make them vulnerable to potential failure and thus the study of their behavior and sug gestion of strengthening techniques are one of the most current engineering issues that structural engineers are requesting solutions for. Through this study, a comprehensive meth odology of structural assessment and recommendation of retrofitting options is carried out 2025-06-01T00:00:00Z