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• Finite element model of stainless steel perforated beam at high temperatures was developed. • Finite element analysis of 400 perforated beams was carried out. • The numerical specimens were subjected to temperatures from 22 - 900 ºC. • Various existing design rules were assessed by compared with 400 numerical data. • Design rules are recommended for stainless steel perforated beams at elevated temperatures. Steel structures are often used in buildings due to their advantage in weight-to-strength ratio. However, their structural capacity deteriorates in fire as the temperature of the structures rises. Investigation of cold-formed stainless steel (CFSS) structures at elevated temperatures is still limited, especially for rectangular hollow section (RHS) beams having a single web hole in the mid-span (perforated web). Therefore, a numerical investigation was conducted to evaluate the current design provisions to calculate the strength of such beams at elevated temperatures ranging from 22 - 900 °C. A total of 400 specimens of stainless steel grades austenitic (EN 1.4301) and lean duplex (EN 1.4162) were considered. The investigation used finite element analysis (FEA) to simulate the behaviour of RHS beams with perforated web under pure bending. The finite element (FE) model was validated against a series of experimental results available in literature. The comparison between flexural strengths obtained from FEA with design values calculated from the current design rules showed that the design rules are conservative. However, they are not always reliable and safe for RHS beams without and with a perforated web for the two material grades at elevated temperatures. In this study, only the design rules specified by Eurocode 3 are shown to be reliable and safe. [ABSTRACT FROM AUTHOR]

This paper presents an experimental investigation of concrete-filled high strength steel tubular (CFHSST) beams. A total of 35 four-point bending tests were conducted, covering high-strength steel square and rectangular hollow sections with nominal 0.2% proof stresses of 700 MPa and 900 MPa. Each high strength steel tubular section was filled with concrete materials of strengths equal to 40, 70 and 110 MPa, respectively. Hollow steel tubes were also tested for comparison purpose. Moment capacity of the test specimens was measured, and ductility of the test specimens was calculated, in order to evaluate the structural benefit associated with the composite action between the two materials. It was shown that both moment capacities and ductility of the CFHSST beams were significantly increased compared to the corresponding hollow sections without concrete infill. It should be noted that the very high strength steel material of 900 MPa is not covered in any design provisions. The current design equations were derived based on normal steel and concrete grades. The suitability of the current design rules, including American Specification (AISC) and European Code (EC4), was assessed for concrete-filled high strength steel tubular sections subjected to bending. • A total of 35 concrete-filled steel tubes were tested under four-point bending. • Steel materials of yield strength equal to 700 and 900 MPa were investigated. • Design equations in American Specification and European Code were assessed. [ABSTRACT FROM AUTHOR]

• Four point bending tests were conducted on 18 ferritic stainless steel perforated beams. • Finite element model was developed and validated against experimental results. • Parametric study with 146 specimens was performed. • The influence of hole size and section geometry on flexural capacity has been evaluated. • Direct strength method for flexural capacity prediction was assessed. Ferritic stainless steel has been increasingly used in construction industry due to its excellent mechanical properties and a relatively low price compared with other grades of stainless steel materials. Experimental and numerical investigation was performed to examine the structural behavior of ferritic stainless steel perforated beams. The experimental program consisted of twenty specimens of rectangular hollow sections subjected to four-point bending, based on which finite element model has been developed for further parametric study. The influence of hole size and section slenderness on the test and numerical specimens was evaluated. It was shown that moment capacity and curvature at ultimate moment had negligible effect for specimens with hole diameter up to 20% of web depth, but reduced when hole size beyond 20% of web depth in this study. The section slenderness of perforated beams was found to have little influence on reduction of moment capacity for the hole diameter up to 70% of web depth. The test and numerical results were also compared with design strengths predicted by the current direct strength method for cold-formed carbon steel perforated beams. It was shown that the current design rules provide conservative predictions to the cold-formed ferritic stainless steel perforated beams. In this study, modified design rules based on the direct strength method were proposed, and shown to improve the accuracy of these design rules in a reliable manner. [ABSTRACT FROM AUTHOR]

The present work investigates structural response of tidal stream turbine blades subjected to impact loads from sea animals. A full-scale tidal turbine blade model was developed using a finite element modelling software ABAQUS, while a simplified geometry of an adult killer whale (Orcinus orca) was assumed in simulating impact on the blade. The foil profiles along the turbine blade were based on the NACA 63-8XX series, while the geometric and material properties of the sea animal were calibrated with experimental results. The numerical model simulated the dynamic response of the blade, accounting for radial velocities of the blade corresponding to real life scenarios. Different magnitudes and trajectories of the velocity vector of the sea animal were simulated, in order to investigate their influence on the turbine blade's plastic deformation. Furthermore, multiple impacts were analysed, in order to monitor the accumulation of plastic strain in the material of the blade. Finally, the potential application of stainless steel material in tidal stream turbine blades for impact resistance was evaluated, through comparison of numerical results obtained from models using stainless steel and mild carbon steel materials. [ABSTRACT FROM AUTHOR]

Numerical investigation of cold-formed stainless steel beam–columns at elevated temperatures ranged from 24–960 °C has been performed. The beam–column specimens were subjected to axial compression and minor axis bending. A finite element model was developed and validated against available experimental results at ambient temperature. An extensive parametric study with 308 lean duplex, austenitic and duplex stainless steel beam–column specimens of square and rectangular hollow section was carried out, and the numerical results were compared with the design strengths calculated by the American Specification, Australian/New Zealand Standard, European Code, and direct strength method. The suitability of these design rules for cold-formed stainless steel beam–columns at elevated temperatures were assessed by reliability analysis. It is shown that the existing design specifications are generally capable of predicting the cold-formed stainless steel beam–column strengths at elevated temperatures, and they are all considered to be reliable according to reliability analysis. The direct strength method provides the most accurate prediction when the carbon steel curve was used. The European Code provided the most conservative prediction among the design rules assessed in this study. • Finite element model of stainless steel beam–columns were developed. • Finite element analysis of 308 beam–column members was carried out. • The numerical specimens were subjected to temperatures from 24–900 °C. • Various existing design rules were assessed by compared with 308 numerical data. • Design rules are recommended for stainless steel beam–columns at elevated temperatures. [ABSTRACT FROM AUTHOR]

• Residual stresses and deformations of I-section curved beams with different curvatures were measured using the cutting strip and novel 3D scanning methods, respectively. • Welding process of the I-section curved beam was precisely simulated using the finite element method. • Effects of the welding sequence, welding speed, and curvature on the residual mechanical properties of the welded I-section curved beams were investigated. • Reasonable welding sequences, welding speeds, and curvatures of the I-section curved beams were recommended. This paper presents an experimental and numerical investigation on welding-induced residual stresses and deformations of in-plane curved welded I-section steel beams. Two welded curved beams with different curvatures were investigated. After welding the curved beam, the residual deformations were measured by a 3D scanner. The residual stresses were subsequently obtained through a high-precision sectioning method. The effects of curvature on the magnitude and distributions of residual deformations and stresses at the specific sections were analysed with the test results. It was found that the residual deformation gradually increased from the weld region to both ends of the flange plate, and the torsion in the web plate became severe with a decrease in curvature of the curved beam. Moreover, the welding process of the curved beam was simulated using the finite element (FE) method. The developed FE model was validated against the test results, and thereafter, parametric analyses were conducted to assess the influence of welding sequence, welding speed, and curvatures of the curved beam on the welding residual stresses and deformations. The numerical results demonstrated that the residual stresses and deformations were significantly influenced by welding speeds, but the influence from curvature of the curved beam was relatively small. Finally, a reasonable welding sequence, welding speed, and curvature of the curved beams were recommended. [ABSTRACT FROM AUTHOR]

• Cyclone-induced damage of traditional wooden houses in east coastal regions of Madagascar were evaluated. • Field test methods were developed, and tests carried out to evaluate the strength of members and connections at two coastal study sites. • Uncertainties related to wind loads and structural properties are considered. • A wind fragility model is developed for these houses based on the performance of the M−T joints, wrapped connections and embedded columns. Cyclones are a common hazard in Madagascar, each year causing fatalities and damage to the physical and socioeconomic infrastructure. Residential infrastructures are a critical sector within the built environment and studying their performance under natural hazards is a significant step for assessing the risk and resilience of a community. In the coastal regions of Madagascar, more than 80% of houses are self-built, non-engineered traditional wooden houses constructed based on heritage practices and using low or no-cost materials collected in nearby areas or forests. These traditional wooden houses are particularly vulnerable to cyclonic winds, and in this paper, a novel approach is used to evaluate their structural performance and to predict their likelihood of failure under extreme wind conditions. The structural systems and their damage due to extreme winds were first evaluated based on field surveys and collected information such as post-disaster reports. A range of field tests was then carried out at two coastal sites to evaluate the strength of the members and connections identified as commonly used for constructing traditional wooden houses in Madagascar. Damage fragility curves were subsequently developed based on the performance of the connections of roof coverings, wall claddings, the roof structural system, and the performance of columns embedded into the ground and combined to predict the structure's performance. The experimental methods and results presented in this study can be exploited to improve the existing Malagasy guidelines for cyclone resistance of traditional wooden houses published in 2016. The developed fragility curves can also be used to represent traditional wooden houses within a community for risk or resilience assessment under cyclonic wind conditions. [ABSTRACT FROM AUTHOR]

This study investigated the effect of travelling fire scenarios, span–thickness ratios, and recurring ages on the post-fire residual behaviour of small-scale continuous reinforced concrete slabs. The mechanical performance of five fire-damaged continuous slabs and one reference slab were investigated, including load–deflection curves, concrete and reinforcement strains, cracking patterns, and failure modes, and the observations were compared with those discussed in companion papers. In addition to considering the boundary restraint and failure criteria, this study proposed a simple ellipse equation to determine the tensile membrane action region and residual ultimate loads of concrete slabs at the limit state. The results indicated that the travelling fire scenario, including the fire direction and time delay, had a slight effect on the residual behaviour of fire-damaged slabs with larger span–thickness ratios. For fire-damaged slabs with larger span–thickness ratios, flexural failure easily occurred with sufficient development of the tensile membrane action. The proposed ellipse method can be used to accurately determine the residual ultimate loads of fire-damaged continuous slabs with large span–thickness ratios. • Tests on the post-fire behaviour of five small-scale continuous RC slabs were conducted. • The influence of travelling fire scenarios, span-thickness ratio, and recurring ages was investigated. • The developed ellipse equation method can predict the tensile membrane action region of the continuous concrete slabs. • Boundary restraint is considered to determine the residual ultimate loads of concrete slabs. [ABSTRACT FROM AUTHOR]

• Experimental investigation on cold-formed steel and timber board composite panel was performed. • Mechanical properties, connector behaviour and flexural strength of the composite panel were obtained. • Structural benefits due to the composite action between the two materials were quantified. • Existing design rules to predict moment capacity and flexural stiffness were assessed. Timber panels and cold-formed steel sheeting are widely used in the construction industry, especially in prefabricated structures, temporary housing and informal settlements. This is because these materials are widely available, can be cut and fixed with hand tools, and their lightweight makes them easy to transport and build with. When used together, there is a potential for composite action developing between the timber panels and the underlying steel sheeting, which is currently ignored in design. A composite panel of oriented strand boards and cold-formed steel sheeting is proposed herein and its overall structural behaviour is experimentally investigated. Based on results obtained from material, push-out and flexural tests, its mechanical properties are determined and the predominant failure modes are highlighted. The feasibility of mobilising composite action between the components of the proposed system is proven and the derived benefits, both in terms of load carrying capacity and stiffness, are quantified. It is demonstrated that harnessing the beneficial influence of composite action can lead to substantial improvements of the overall structural performance of the proposed composite panel, offering the potential to improve significantly the quality of housing in informal developments and rapidly urbanising areas. [ABSTRACT FROM AUTHOR]

• Develop an analytical method to predict the ultimate loads and deflection of the two-way supported concrete slabs. • The prediction of the method is agreed well with the test and numerical results. • The developed method can be used for predicting the ultimate loads and failure modes of the two-way simply supported RC slabs at large deflections. • The method can reasonably predict the tensile membrane action region and failure modes of the two-way concrete slabs. This paper presents a newly developed method for determining the influence of tensile membrane action on the ultimate loading capacity of a two-way RC concrete slab. In this method, more realistic membrane action and two failure criteria of a slab panel are established. The developed method has been validated against the test results and good agreement is achieved. Compared to the tensile membrane action region obtained from the FEM (Vulcan), the assumptions about the focus of the ellipse equation proposed within the present method are reasonable and accurate. The present method can be used for predicting the ultimate loads and failure modes of the two-way simply supported RC slabs at large deflections. The research indicates that the in-plane shear force has considerable effect on the prediction of ultimate loads of the slabs and neglecting the in-plane shear force results the overestimated the concrete corner strains. [ABSTRACT FROM AUTHOR]