Ultra-high-performance fibre-reinforced concrete (UHPFRC) is a cementitious composite which contains fibres. UHPFRC has emerged as an effective structural retrofitting material due to its superior mechanical properties. In addition, UHPFRC has outstanding durability, ductility and workability; a low permeability; and a high abrasion and fire resistance. These improved characteristics of UHPFRC are obtained by reducing the content of free water in the concrete matrix (leading to less air voids), introducing high strength ductile steel fibres, replacing coarse aggregates with well graded fine aggregates and introducing highly active pozzolanic materials. UHPFRC has excellent bonding with normal strength concrete and it eliminates the issue of debonding which is common in other retrofitting techniques employing fibre-reinforced polymers or externally bonded steel plates. Therefore, considering various aspects, UHPFRC-based structural retrofitting possesses a number of advantages. This paper presents a review of previous studies employing UHPFRC for structural retrofitting applications, highlighting its advantages, limitations and challenges. Aspects of flexural strengthening, combined axial and flexural strengthening, shear strengthening, impact resistance and torsional strengthening are considered for this review. Altogether, the paper aims to enhance the awareness of UHPFRC for structural retrofitting as a step forward towards effective field applications and to outline the potential future directions of research.

The assessment of seismic risk for critical and strategic structures like schools and hospitals remains crucial, even in regions with low seismic activity. Presently, operational school buildings in Sri Lanka are primarily designed to handle gravitational loads without considering capacity-based design principles. Consequently, these structures may lack the necessary lateral resistance to mitigate potential damage or collapse during future earthquakes in Sri Lanka. Hence, conducting seismic risk assessments for such school buildings is imperative to ensure the safety of their occupants. In this research paper, we utilize a recently developed probabilistic seismic hazard map for Sri Lanka to evaluate seismic risk. We employ two nonlinear 3-D finite element models of school buildings created in OpenSees. Incremental Dynamic Analysis is conducted using a well-established set of ground motions, continuing until the structure approaches the point of collapse, to determine the probability of collapse prevention. Subsequently, we develop fragility functions for two limit states, immediate occupancy, and collapse prevention. These fragility curves are then used to compute the probability of exceeding these limit states, aiding in the assessment of the structural safety of the school buildings. A key outcome of this analysis reveals a general trend of increased damage probabilities as the number of stories in the buildings increases despite the distinct structural characteristics of each building. It is also important to note that the disparities between the immediate occupancy and more severe damage cases, such as collapse prevention, are notably pronounced in both two- and three-story school buildings.