A Novel Optimised Inter-Locking Connection For Steel Modular Building Systems To Enable Re-Use

Hot-rolled steel Modular Building Systems (MBS) represent the highest level of Off-Site Con-struction (OSC) in which prefabricated, and often prefinished steel modules are delivered to site on a ‘just-in-time’ basis and assembled into complete building systems. Besides the already well-known advantages such as tight tolerance control, reduced on-site human intervention and speedier construction times, the context of the ongoing climate emergency has brought forward the connection between circular economy (CE) and opportunities of steel MBS for disassembly and reuse. However, the use of hybrid structural systems, the functionality of inter-modular connections, and the effects of complex and demanding load transfer paths often question the actual prospects of deconstruction, repair, relocation, or reuse. So far, inter-module connections have been heavily influenced by conventional design methods, relying on bolts, welds or even prestressing strands, which require laborious on-site tasks and simplifying design assumptions, often raising uncertainty about structural behaviour of modular buildings.In an attempt to mitigate limitations of existing systems, a new inter-module connection was envisaged, inspired from the inter-locking method of joining. At the forefront of the develop-ment process, topology optimisation (TO) was adopted in the conceptual design of the main component of the joint, assisting the morphogenesis process which provided the final configu-ration of the novel system. The structural performance of the newly proposed connection was assessed through a series of static monotonic and quasi-static cyclic FE analyses. Results re-vealed that in terms of load-bearing capacity, ductility and energy dissipation ability, the struc-tural behaviour of the new connection was comparable to that of other inter-module joints in literature, while managing to tackle their limitations by introducing both an easy-to-install and easy-to-disassemble configuration with promising opportunities for reuse, further demonstrat-ing that inter-locking joints could be worthy competitors for traditional means of attachment in the future of modular construction.

Structural Behaviour of Green Geopolymer Concrete Beams and Columns Made with Waste Wood Ash a Partial Substitution Binder

On the demand of reducing the global warming due to cement production which is used as main constituent in the production of concrete and minimizing the environmental impact caused by the waste and its disposal methods, this study was aimed. This study looked in to detail insight view on effective utilization of waste wood ash in the production of geopolymer concrete beams and columns to alternate the conventional reinforced concrete elements in construction industry. Waste wood ash is a waste by product produced in the nearby hotel and factories by burning the waste wood collected from timber industries and the ash are thrown in to land which creates a major environmental pollution. Geopolymer is a novel inorganic eco-friendly binding agent derived from alkaline solution that stimulates aluminosilicate source material (such as metakaolin, fly ash and GGBS). In this research, behaviour of beams in deflection, ductility factor, flexural strength and toughness index and columns in load carrying ability, stress strain behaviour and load-deflection behaviours were examined for three types of concretes (30% WWA – 70% Fly ash Geo-polymer concrete, Fly ash Geo-polymer concrete and Reinforced Cement Concrete). The results showed that inclusion of waste wood ash in geopolymer concrete helped in enhancing the load carrying capacity of beam and column by 42% and 28%. Further, the behaviour of structural elements in stiffness, ductility and toughness were also improved with the replacement of waste wood ash.

Seismic Design of Bolted Connections in Steel Structures—A Critical Assessment of Practice and Research

The importance of connections in steel structures is paramount, not only because it greatly influences the cost of construction and provides room for innovations, but also due to the connections’ impact on global structural behaviour. Therefore, research into innovative connections for seismic applications and related design criteria has significantly grown in recent years. However, it has been pursued mostly on local—connection or frame—levels, leaving the system analysis and code compliance levels with a meagre investigation. Moreover, less than 1% of published papers concerning steel connections and earthquake engineering are review articles. To overcome this gap, this systematic review of more than 240 references, including scientific contributions and design codes in the field aimed to cover both recent research and current shortcomings in practice and regulations. It has been found that European design rules updated to a fully performance-based design philosophy is imminent and is deemed to bring pre-qualified joints and increased complexity. Design rules have been systematized, and current hindrances have been highlighted. A deeper look into research needs and trends showed that investigations in connections for concentrically X braced frames are still a necessity, while developments in self-centring and replaceable connections as well as in simple solutions for increasing damping are expected to modify how joints are designed, as soon as semi-rigid and partial strength connections are more easily allowed by design codes.

APPLICATION OF DIGITAL STRUCTURE SIMULATION AS A TOOL FOR THE EXPLORATION OF WIDE SPAN STRUCTURE IDEAS

Review on structure behaviour and visual appearance of a building is needed in generating creativity in the making of an architectural design. The use of any specific structure software will facilitate this in the process. This research aims to prove the effectiveness with which designers can compose alternative forms of architectural appearance through the use of the software. One of the tools in the creative process used in the exploration of 2-dimensional frame structures is DR FRAME. The observations were carried in the Structure and Construction IV Studio at Itenas Architecture Study Program Bandung through a digital simulation using DR. FRAME software demo version. Several students are invited to explore various forms of wide-span truss structures at the level of unified integration. The results through the program execution show various diagrams which can be implemented in the design of the form and the type of structural components. DR.FRAME software enriches ideas in the wide-span structure design which provides an understanding of the relationship between structural behaviour and the appearance of architectural design. The use of other supporting software is supposed to be applied as an alternative search for various structural design ideas for architecture students

Magnetic and Structural Behaviour of Cobalt & Nickel Substituted Calcium W-Type Nanosize Hexaferrites

The available literature and research work on W-type hexaferrites is mainly focused on Co- and Zn-based calcium W-type hexagonal ferrites with a variety of cationic substitutions. The Modifications in the properties of the Calcium W-type ferrite based on Ni2+ as the divalent metal ion, however, is not studied sufficiently in the research literature vailable. In this study, the focus is mainly on the effects of substitution of Ni2+ on the properties of CaCo2W exaferrites. The investigations carried out are mainly XRD, SEM and VSM. The main objective of this research investigation is to study the effect of substitution of Nickel and Cobalt on the structural and magnetic properties of calcium W-type hexaferrite CaCo2-xNixFe16O27 (x=0, 1 and 2). XRD analysis and characterization revealed slight decrease in the values of lattice constants ‘a’ and ‘c’ with increase in concentration ‘x’. The particle size was confirmed from SEM and TEM images. The analysis of VSM for magnetic properties reveals decrease in coercivity and increase in the values of saturation magnetization as concentration increases. The results of measurements made bythe various experimental techniques and the observations were compared to understand the crystalline and magnetic structure of the compounds

Mineralogical Transformations in Granitoids during Heating at Fire-Related Temperatures

Fire is a major decay agent of rocks and can generate immediate catastrophic effects as well as directional and anisotropic damage that affect long-term weathering processes. Temperature increase is the most relevant factor, among other components in a fire, generating mineral transformations and bulk mechanical damage. Mineralogical changes at high temperatures are key to understanding the overall mechanical behaviour. However, most studies to date were carried out after rock specimens were heated to a target temperature and cooled down to room temperature. Therefore, these studies are missing the observation of the actual mineral processes during heating. This paper aims to compare mineralogical changes in crystalline rocks during heating by means of XPS and different XRD techniques. Samples of four different granitoids were heated to several temperatures up to 1000 °C to evaluate their chemical and structural changes. Results show how standardised thermal expansion coefficients are not a suitable indicator of the bulk effect of high temperatures on rocks. Results also show how thermal expansion estimations from XRD lattice measurements may be an alternative to bulk dilatometric tests, as they can be performed with limited sampling, which may be necessary in some studies. Nevertheless, XRD and XPS results need to be interpreted carefully in relation to the bulk effects of temperature increase in the rocks, as the structural behaviour may seemingly contradict the macroscopic effect.

Influence of Aqueous Phase Composition on Double Emulsion Stability and Colour Retention of Encapsulated Anthocyanins

Water-in-oil-in-water (W1/O/W2) emulsions (double emulsions) have often been used for the encapsulation of bioactive compounds such as anthocyanins. Instability of both anthocyanins and double emulsions creates a need for a tailored composition of the aqueous phase. In this work, double emulsions with a gelled internal water phase were produced and monitored over a 20-day storage period. The effect of the electrolyte phase composition (varying electrolyte components, including adipic acid, citric acid, and varying concentration of potassium chloride (KCl)) on anthocyanin and double emulsion stability was analysed using colour analysis, droplet sizing, and emulsion rheology. The effect of electrolytes on colour retention was shown to differ between the primary W1/O emulsion and the secondary W1/O/W2 emulsion. Furthermore, droplet size analysis and emulsion rheology highlighted significant differences in the stability and structural behaviour of the emulsions as a function of electrolyte composition. In terms of colour retention and emulsion stability, a citrate-buffered system performed best. The results of this study highlight the importance of strict control of aqueous phase constituents to prevent anthocyanin degradation and maximise double emulsion stability. Additional experiments analysed the effect of pectin chemistry on the anthocyanin colour retention and leakage, finding no conclusive difference between the unmodified and amidated pectin.