Browsing by Author "Jayaweera, GCS"

Filter results by typing the first few letters
Now showing 1 - 4 of 4
  • Thumbnail Image
    item: Conference-Full-text
    Case studies on blast behaviour of glass façades: Sri Lanka easter bombings
    (IEEE, 2022-07) Jayaweera, GCS; Hidallana-Gamage, HD; Baleshan, B; Rathnayake, M; Adhikariwatte, V; Hemachandra, K
    Sri Lanka Easter attacks were done by coordinated suicide bombers on 21 st of April, 2019. This paper investigates the damages to the glass façades due to the explosions that occurred inside the five-star hotels, Shangri-La, and Kingsbury in central Colombo. It is evident from previous explosions that the blast-related injuries are mainly caused by the free-flying glass fragments. Laminated Glass (LG) will provide better resistance to explosions that occur outside the building if they are properly designed to be held on the supporting structure. Because, if the blast pressure enters the building, it will cause severe damage to the building elements while creating injuries to the occupants. However, when an explosion occurs inside the building, damage to the building elements and occupants will be severe if the blast pressure cannot escape from the confined building premises easily. Therefore, both of these aspects should be considered when designing glass façades for a credible blast load. LG has better blast resistance than monolithic glass. This paper presents a comprehensive review on the effect of the Easter bombings on glass façades and some design strategies which can be recommended for blast-resistant glazing with the evidence from available literature and design standards.
  • Thumbnail Image
    item: Conference-Full-text
    Development of design guidance for circular reinforced concrete columns incorporating crack width
    (2021-07) Jayaweera, GCS; Hidallana-Gamage, HD; Indrajith, WPR; Adhikariwatte, W; Rathnayake, M; Hemachandra, K
    Maximum crack width of reinforced concrete (RC) structures should be controlled for satisfying the serviceability and durability requirements of the structures. However, the crack width analysis of RC structures is not much easy because of the complexity of the parameters which affect the crack width. In the Sri Lankan context, there is no specific simplified guidance in terms charts and tables for crack width calculations of circular RC columns. Hence, it is important to develop such guidance. This research deals with the crack width analysis of circular RC columns in straight viaduct sections. A comprehensive study was carried out regarding the behaviour of the cracks in circular RC columns in viaduct sections as per the design standard, BS 5400. Autodesk Structural Bridge Design software was used to perform crack width calculations and MIDAS Civil software was used to do the Finite Element Analysis (FEA) and validation process. The comprehensive design charts developed in this research will be useful in calculating the crack widths in circular RC columns without following any time-consuming methods. Therefore, the findings of this research will be helpful to enhance the efficiency of the design work related to the crack width calculations of circular RC columns.
  • Thumbnail Image
    item: Conference-Abstract
    Development of design guidance for circular reinforced concrete columns incorporating crack width
    (Department of Civil Engineering, University of Moratuwa, 2021) Jayaweera, GCS; Hidallana-Gamage, HD; Indrajith, WPR; Hettiarachchi, P
    The maximum crack width of Reinforced Concrete (RC) structures should be controlled for satisfying the serviceability and durability requirements of the civil engineering structures. Therefore, care must be taken at the initial design stages for maintaining the possible crack widths within a permissible range which has been specified under the design standards. However, the crack width analysis of RC structures is not easy because of the complexity of the parameters which affect the crack width. If crack width calculation is skipped, the width of the cracks in real concrete structures can be larger than the maximum limiting allowable value. Circular RC columns and piles are widely used structural components in modern civil engineering construction projects. As an example, circular RC piles and columns can be seen in many expressway construction projects in Sri Lanka to support viaduct structures. The main aim of this research is to develop design guidance for circular RC columns to estimate the crack width. In the Sri Lankan construction industry, there is no specific simplified guidance in terms of charts and tables for crack width estimations of circular RC columns. Hence, it is important to develop such design guidance for circular RC columns. Although there are a variety of applications of circular RC columns in the industry, this research deals with the crack width analysis of circular RC columns in straight viaduct sections. A comprehensive study was carried out regarding the behaviour of the cracks in circular RC columns in viaduct sections as per the design standard, BS 5400. Autodesk Structural Bridge Design software was used to perform crack width estimations, and MIDAS Civil software was used to do the Finite Element (FE) analysis and validation process. The crack width can be estimated to a 0.01 mm accurately by using the charts developed in this research. This design guidance is simple to understand, and use. Hence, engineers can perform their preliminary crack width estimations with less effort using correctly specified methods. Crack width estimation charts were developed for both uniaxial bending and biaxial bending cases of short circular RC columns with a diameter of 1.5 m, C 25/30 concrete, a nominal cover of 45 mm, and the main rebars all of the same diameter. According to the parametric study done for the circular RC columns subjected to uniaxial bending, the following details were found. Crack width reduces with increasing bar diameter and number of main rebars. Crack width is low in the columns with high-grade concrete. When the ratio of Mq/Mg as defined in BS 5400 is decreased, the crack width also decreases. A significant variation of the crack width can be seen in the cases where, the ratio, Axial load (ULS)/(Column diameter)2 is in the range of 0.5 to 2.5 N/mm2. The width of the crack is significantly higher in the case of having higher bending moments with low axial forces. This research can be extended to develop design guidance for estimating the crack width following latest standards such as Eurocodes and produce more charts by accounting for the requirements of the design engineers. The comprehensive design charts developed in this research will be useful in estimating the crack widths in circular RC columns without the need to follow time-consuming methods. Therefore, the findings of this research will be helpful to enhance the efficiency of the design work.
  • Thumbnail Image
    item: Thesis-Full-text
    Investigating the performance of laminated glass panels under windborne debris impact
    (2023) Jayaweera, GCS; Damruwan HGH; Baleshan B
    Glass façades, a prominent feature in modern buildings, have garnered widespread popularity despite the inherent brittleness of glass due to its non-crystalline molecular structure. While glass is commonly utilised as a structural material following quality and performance enhancement measures, its susceptibility to extreme loads, particularly impact loads, is higher compared to other structural elements. Past investigations into windstorms have revealed that the generation of various debris poses a significant threat to glass façades during extreme wind conditions. This research addresses the imperative need to comprehensively study the response of Laminated Glass (LG) panels to windborne debris impact, emphasising the potential consequences of damage during windstorms. LG, known for its safety features and higher post-crack load carrying capacity, is employed in buildings. The study focuses on fully framed LG window panels and employs a finite element (FE) based numerical modelling approach to assess their impact performance. The FE models are validated using results from past experiments, and subsequent examinations explore the impact performance of LG panels and their constituent components under various critical impact locations. Key findings suggest that support conditions and impact locations significantly influence the LG panel's impact performance. The Polyvinyl Butyral (PVB) interlayer plays a crucial role in resisting penetration by absorbing substantial impact energy. The study advocates purposeful design of LG window panels as sacrificial elements to enhance impact resistance, rather than relying solely on thicker glass panes. Energy absorption is found to be highest for mid-impacts, diminishing for long-span mid-impacts, short-span mid-impacts, and corner impacts, respectively. The research highlights the importance of an iterative design process for impact-resistant glazing, emphasising the need for designers to propose suitable layer thicknesses and configurations. Failure to do so may result in additional material costs without achieving satisfactory impact resistance. Hence, the findings of this research encourage manufacturers to create innovative materials with strong energy absorption, enabling engineers to implement impact-resistant glazing for safe, optimised, and aesthetically pleasing glass façades in cyclone-prone areas. Keywords: Windborne debris impact; Impact-resistant glazing; Laminated glass; Finite element modelling; Material failure