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In existing design practices selection of circular or square column shape mostly depends upon architectural needs rather than structural behavior. The behavior of equivalent area (circular and square), high strength reinforced concrete columns is reported to be same under monotonic loading conditions but their behavior under fatigue loading is not well-established. This paper presents the comparison of high strength reinforced concrete circular and square equivalent area columns’ performance (load-deflection behavior) under fatigue loading. Columns were casted in four configurations: square and circular shapes and with and without shear stirrups. Experimental results showed that in case of columns without shear stirrups, the square column resisted 38% more loading cycles as compared to circular column while the maximum deflection was 78% more than the circular column. Similarly, in case of columns with shear stirrups, square shaped column resisted 55% more loading cycles with only 5% more maximum deflections as compared to circular column. The results show that the square columns might be considered more ductile as compared to circular columns under the application of cyclic loading conditions like wind forces or seismic forces. Therefore, it might be concluded that square columns should be recommended for highly seismic regions as compared to circular columns with equivalent area. Doi: 10.28991/cej-2021-03091639 Full Text: PDF

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Greater confinement of the soil foundation may globally reduce the shear span length, which may raise the risk of shear failure of RC piles. On the other hand, soil confinement may improve the flexural ductility of the pile section locally. This study discusses these global and local impacts of soil confinement on the RC-pile mechanistic behaviors, experimentally and analytically. Small-scale mortar-based piles were newly produced as a mockup of real-scale reinforced concrete so as to obtain the consistent nominal shear strength by reducing the shear transfer along cracks to overcome the size effect. Then, the global impact of soil confinement on pile shear failure is reproduced inside the small-scale experimental devices with soil. The soil-pile interaction test also shows the local impact of soil confinement in terms of increasing the flexural ductility of the miniature pile section by suppressing cover spalling and local buckling of reinforcement. It is confirmed that the coupled local and global effects of soil confinement can be consistently taken into account in 3D computational simulation without reducing the degree of freedom for strain fields.

In Egypt during the extreme heat in summer, numerous amounts of air conditioners -that provide a cooler environment -are producing a huge amount of outlet wastewater. The continuous flow of this water causing great damage to buildings' façades. Therefore, the paper presents an innovative product solution made from algae that aim to reuse this wastewater as a self-watering landscape façade element that acts as an irrigation system. The prototype is designed from concept to manufacturing to implementation based on 3D printing with a bio-algae filament. With the dual algae ability in producing O2 and absorbing CO2, the fabrication follows a spiral engrave path to collect and cool the water droplet and ensure a smooth flow to be suitable for plantation. A path strategy is used during the printing for minimal structure supports aimed at saving unnecessary material waste and fabrication time. Solar radiation and water simulation are tested to measure the effect of the algae and to ensure the water fluidity from the AC tube till reaching the soil. The solar radiation results record a solar reduction from 316.43 to 80.71 kWh/m 2 after adding the algae panel to a building façade with a decrease of 6°C in the water temperature. The design demonstrates highly significant materials and resource savings, where no supports are needed during printing. The finding addresses the manufacturing of a low-cost algae product using cleaner technology as additive manufacturing. Given the alarming increase in the new industrial materials, algae will allow designers to explore their benefits regarding their O2 production and CO2 absorption, which will influence the façades to be smarter and sustainable using large-scale of PBRphotobioreactors -applications as a nature-based alternative to large glass surfaces with the potentials of additive manufacturing. This can reduce plastic production using fossil fuels to be eco-friendly.