Improving the Performance of Structural Members by Incorporating Incinerated Bio-Medical Waste Ash in Reinforced Geopolymer Concrete

This study aims to analyze the use of Incinerated Bio-Medical Waste Ash (IBWA) in reinforced concrete structural member with ground granulated blast furnace slag (GGBS) as an alternate building ingredient instead of cement. Biomedical waste was produced from various medical resources such as hospitals, medical institutes and research centres. GGBS is the waste generated from the steel plant. The climate is now being affected by the release of CO2 (global warming) from the Portland cement industries. Therefore, greater attention must be paid to study efforts to use geopolymer concrete. Geopolymer is a novel inorganic eco-friendly binding agent derived from an alkaline solution that stimulates aluminosilicate source material (GGBS, Rice Husk Ash, Quartz Powder, metakaolin, fly ash and Silica Fume). In this research, laboratory tests for Reinforced Geopolymer Concrete (RGPC) beams (deflection, ductility factor, flexural strength and toughness index) and columns (load-carrying ability, stress-strain behaviour and load-deflection behaviour) were conducted for three types of proportions using [30% IBWA – 70% GGBS Geopolymer concrete, GGBS Geopolymer concrete and Reinforced Cement Concrete. The experimental findings revealed that the performance of reinforced 30% IBWA – 70% GGBS geo-polymer beams and columns worked more effectively than reinforced cement concrete beams and columns.

Various Geometric Configuration Proposals for Dovetail Wooden Horizontal Structural Members in Multistory Building Construction

Adhesives and metal fasteners have an important place in the content of engineered wood products (EWPs). However, adhesives may cause toxic gas emissions due to their petroleum-based nature, while metal fasteners may adversely affect the reusability of these products. These issues also raise important questions about the sustainability and environmental friendliness of EWPs. Thus, there is still room for a solution that is solid and completely pure wood, adhesive- and metal-connectors-free dovetail wood board elements (DWBEs). There are many studies on the technological, ecological, and economic aspects of these products in the literature, but no studies have been conducted to assess the technical performance of DWBEs. This chapter focuses on DWBEs by proposing various geometric configurations for horizontal structural members in multistory building construction through architectural modeling programs. In this architectural design phase, which is one of the first but most important stages, the proposed configurations are based on a theoretical approach, considering contemporary construction practices rather than structural analysis or mechanical simulation. Further research, including technical performance tests, will be undertaken after this critical phase. It is believed that this chapter will contribute to the dissemination of DWBEs for innovative architectural and structural applications, especially in multistory wooden structures construction.

Behaviour of One-Way Reinforcement Concrete Cantilever Slabs with Openings

In some concrete structures, openings are placed because of the need for several utility requirements. These openings could affect the strength of the structural members. So the behavior of reinforcement concrete (RC) cantilever slab containing openings and its effect is the subject of the study. Opening shapes, numbers and sizes are the main variables that have been studied in this research. Five RC cantilever slabs were cast and tested; one is without openings and the other four slabs are with openings. It is found that there is a significant effect of openings on the behavior of these slabs. Where, the decrease in the ultimate load (from 39kN to 24.7kN), while the decrease in the deflection at ultimate load (from 67 mm to 35 mm).

Dynamic bearing capacity of point fixed corrugated metal profile sheets subjected to blast loading

Blast loading scenarios and the corresponding hazards have to be evaluated for infrastructure elements and buildings especially at industrial sites for safety and security issues. Point fixed corrugated metal sheets are often applied as façade elements and can become a hazard for humans if they are pulled off. This paper investigates the dynamic bearing capacity of such structural members in terms of their general bending behavior in the middle of the span and pull-out behaviors at the fixing points. The elements are fixed at two sides and the load transfer is uniaxial. An experimental series with static and dynamic tests forms the basis to identify the predominant failure modes and to quantify the maximum stress values that can be absorbed until the investigated structural members fail. The experimental findings are applied to create and to optimize an engineering model for the fast and effective assessment of the structural response. The aim is the derivation of a validated model which is capable to predict the blast loading behavior of metal sheets including arbitrary dimensions, material properties, and screw connections. Results of this study can be integrated into a systematic risk and resilience management process to assess expected damage effects and the evaluation of robustness.

LOAD-BEARING CAPACITY ANALYSIS FOR STRUCTURAL COLD-FORMED MEMBERS SUBJECTED TO CENTRAL COMPRESSION

The main purpose of the research was a deep analysis and verification of the consistency and completeness of the design code relating to calculation of load-bearing structural members made from cold-formed profiles. The work has been done in close connection with the implementation on the territory of Ukraine of this design code. The article has discussed and investigated the load-bearing capacity of structural members made of cold-formed profiles subjected to the action of central compression. A system of constraints has been presented, in which the strength and buckling constraints for thin-walled cold-formed column members are formulated, taking into account their possible post-buckling behavior, namely, the ability to resist external loads and effects even after the occurrence of the local buckling and/or distortional buckling phenomenon. The performed load-bearing capacity investigation has shown that for the mono-symmetric cold-formed profiles, the flexural-torsional buckling is determinative. For such cold-formed profiles, the effect of the overall dimensions ratio (flange width to web height) on the load-bearing capacity of cold-formed profiles has been estimated. It has been shown that for the same cross-sectional area the load-bearing capacity of a column structural member made from cold-formed profile and subjected to axial compression can be significantly increased by assigning an optimal ratio of flange width to web height. The paper also has presented the results of the load-bearing capacities for the structural cold-formed members subjected to central compression, calculated according to the design standard DSTU-N B EN 1993-1-3: 2012 and according to the design code DBN V.2.6-198: 2014. It has been shown that in some cases the difference in the assessment of the load-bearing capacity for such structural cold-formed members reached 25%. A comparison of the load-bearing capacities for the action of the central compression has been made for structural cold-formed members made from a C-shaped profile and with a composite section of two C-shaped profiles. It has been shown that the load-bearing capacity of the structural cold-formed member of the composite section exceeds the load-bearing capacity of the member with single C-shaped profile by more than 3 times, while cross-section areas of these structural members differ only doubly.

Mechanical Behaviour of Aluminium-Timber Composite Connections with Screws and Toothed Plates

This paper presents an investigation of the load-slip behaviour of aluminium-timber composite connections. Toothed plates with bolts are often used for connecting timber structural members with steel structural members. In this paper, toothed plates (C2-50/M10G, C2-50/M12G or C11-50/M12) have been used as reinforcement in aluminium-timber screwed connections for the first time. The push-out test specimens consisted of laminated veneer lumber slabs, aluminium alloy beams, and hexagon head wood screws (10 mm × 80 mm and 12 mm × 80 mm). Of the specimens, 12 additionally had toothed plates as reinforcement, while 8 had no reinforcement. The load carrying-capacity, the mode of failure and the load-slip response of the strengthened and non-strengthened screwed connections were investigated. The use of toothed plate connectors was found to be effective in increasing the strength of aluminium-timber composite connections and ineffective in improving their stiffness. The examined stiffness and strength of the connections can be used in the design and numerical modelling of aluminium-timber composite beams with reinforced screwed connections.

Tracking of Stiffness Variation in Structural Members Using Input Error Function Observers

This study evaluates input error function observers for tracking of stiffness variation in real-time. The input error function is an Analytical Redundancy (AR)-based diagnosis method and necessitates a mathematical model of the system and system identification techniques. In practice, mathematical models used during numerical simulations differ from the actual status of the structure, and thus, accurate mathematical models are rarely available for reference. Noise is an unwanted signal in the input–output measurements but unavoidable in real-world applications (as in long span bridge trusses) and hard to imitate during numerical simulations. Simulation data from the truss system clearly indicates the effectiveness of the proposed structural damage detection method for estimating the severity of the damage. Optimization of the input error function can further automate the stiffness estimation in structural members and address critical aspects such as system uncertainties and the presence of noise in input–output measurements. Stiffness tracking in one of the planar truss members indicates the potential of optimization of the input error function for online structural health monitoring and implementing condition-based maintenance.

SHOCK RESILIENCE OF STRUCTURAL PILLARS IN NAVAL VESSELS

Although structural pillars are extensively used in commercial vessels, traditionally their use on board UK warships has been discouraged. This is due to the tendency of pillars to “punch through” the deck when subjected to the high impulse loading of shock from underwater explosions (UNDEX). There are however many spaces within naval ships that would significantly benefit from the wide-open spaces created from the use of pillars as opposed to full bulkheads, such as machinery rooms, mooring decks and accommodation flats. This paper re-addresses the question of a shock capable pillar, looking at how a pillar can be designed or mounted to increase its resilience to shock from underwater explosions. It is proposed that the advice against the use of pillars in warships could be unfounded; this is supported by the fact that not all navies reject their use. The results of this study imply that as long as the pillar is sited properly on primary structural members, then pillar buckling should occur long before “punch though”.

A Proposal to Improve the Effectiveness of the Deflection Control Method Provided by Eurocodes for Concrete, Timber, and Composite Slabs

Limited deflection of structural members represents an important requirement to guarantee proper functionality and appearance of building and infrastructures. According to Eurocodes, this requirement is ensured by limiting the maximum deflection of horizontal structural members to a fraction of their span. However, each Eurocode provides different maximum deflection limits, which are independent of the type of superstructures considered. Thus, the respect of these limits may not always guarantee the integrity of certain superstructures. In this paper, the reliability of the Eurocode deflection control methods, in guaranteeing the integrity of the superstructures, is assessed and discussed. First, different types of horizontal member, namely rib and clay (hollow) pot, composite steel–concrete, and timber beam slabs are designed to respect the deflection limit enforced by the Eurocodes. Then, the maximum curvature developed by these members is compared with the ultimate (limit) curvatures of various superstructures (e.g., ceramic and stone tile floorings). The results obtained show that the approach adopted by Eurocode 2 may provide non-conservative results, but also that the rules proposed by Eurocodes 4 and 5, albeit more reliable, do not always guarantee the integrity of the superstructure. Based on these results, an alternative method, based on the curvature control, is proposed and its advantages and limitations critically discussed. This method appears simpler and more reliable than the method currently adopted by the Eurocodes.