Research on Engineering Structures and Materials

481-504

Authors: Ismail Luhar, Salmabanu Luhar

“More industrial developments equals more generation of wastes". Wastes of glasses are blameworthy for the grave issue of pollution of environments chiefly in virtue of their profound accessibility and inconsistency of this stream. With mounting environmental pressure to trim them down and to recycle them as much as possible, the concrete industry has lent a hand to incorporate them with the manufacturing of inorganic, user, and eco-benevolent innovative Geopolymer construction composites. The current review paper studies the most striking points in the context of the production of waste glass integrated Geopolymer paste stressing its valorization in lights of its properties. More often than not, the center of attention here is to embrace the "conversion of wastes into wealth" strategy. That is why, this article reviews with an objective of its confined literature to comprehend its characteristics viz., workability, compressive strength, thermal, microstructure, etc. As a final point, the paper pigeonholes research work challenges, endorsement of potential utilization for this promising brand-new, green valorized Geopolymeric building material in order to establish it as a cost-effective, sustainable, durable construction material as a "futures toolkit”.

523-538

Authors: Giovanni Falsone, Gabriele La Valle

In this work, the free vibration and the stability problems of functionally graded beams are analysed via the Timoshenko theory through the Navier procedure and via an appropriated finite element (FE) approach. In particular, it is shown how the definition of homogenized/generalized displacements allows to uncouple boundary conditions, obtaining a remarkable advantage in terms of computational effort. Moreover, a unified expression capable to express the buckling load for different constrain conditions is discovered. The latter may be considered the natural extension of the Euler’s one derived in the century XVIII. In order to verify the reliability of the proposed method, natural frequencies, buckling loads and static displacements of differently constrained beams are numerically evaluated.

551-577

Authors: Sahar Ismail, Wassim Raphael, Emmanuel Durand

Analysis of the structural failure of the Beirut port silos by the August 4, 2020 explosion is presented in this paper. The structural response of the silos due to the blast loading imposed by the explosion was assessed using 3D laser scan. Then, the silos were modeled using three-dimensional finite element models using Abaqus explicit. The silos’ damage and failure were investigated to estimate the blast magnitude and to check the silos structural response against the silos’ concrete strength and additional reinforcement and concrete coating added to the silos in 2000. In addition to the effects of reinforcing the ribs between the silos as well as the soil and foundation. Therefore, these parameters were tested after estimating the blast magnitude to check the structural status of the remaining part of the Beirut port silos (if they can be reusable), the role played by the foundation and soil and if the silos’ response would have changed if certain parameters were taken differently in the design. In this article, the damage and silos’ displacement obtained from the numerical models were compared to the results obtained by the 3D laser scan. The results of this investigated article show that a blast magnitude of 337.5 tons TNT (938 tons of Ammonium Nitrate) best captures the silos’ displacement and damage amount. The silos exhibit a tilt between 20 and 30 cm in the direction of the blast. The numerical results indicate that constructing the silos with higher compressive strength would not have affected the silos’ damage. Nevertheless, adding the extra concrete coating and reinforcement layer in 2000 to the outer silos decreased the amount of damage in the silos. Moreover, reinforcing the ribs between the silos would have decreased the silos displacement and damage amount. Finally, the soil and the foundation played a positive role in the explosion by absorbing part of the released energy while the silos, in the current state, cannot be reused.

595-615

Authors: Anjeza Gjini, Hektor Cullufi, Enio Deneko, Princ Xhika

On November 26, 2019, an earthquake with magnitude Mw = 6.4 occurred in the city of Durrës, with epicenter about 16 km southwest of Mamurras. This seismic event caused 51 loss of life, hundreds injured and hundreds of damaged buildings. One of the typified structures, identified by the authors with the most cases of damage or even collapse, is the structure Type no. 82/2 built in some areas of the city of Durrës, in the period 1983-1993. The purpose of this study is to analyze the behavior of this type of structure during seismic loading (for two cases, five and six storey, from the same typology), using the non-linear static procedure (Pushover). The obtained results are compared with the damages recorded in the field for these buildings, concluding with their main causes. According to this study it appears that the main cause of failures occurred in this type of building is the reduction of the reinforcement amount from the ground floor to the first floor by 35.5% and percentage of reinforcement required for the given section exceeds the requirements of design standards (Eurocode-2 and KTP-2-89) by around 30%. Also on these failures contribute the low strength of concrete used in construction of some of these buildings (the compressive strength results 50% less than required) and the use of smooth rebar.

635-646

Authors: Akshansh Mishra, Devarrishi Dixit, Raheem Al-Sabur

A wide range of opportunities in the field of automotive and structural applications are being offered by Magnesium matrix composites because of their enhanced mechanical properties. Magnesium alloys based on Metal Matrix Composites (MMCs) are the best candidates for lightweight structural applications due to their improved creep properties. In the present study, three specimens of specially reinforced magnesium composites were manufactured by using the squeeze casting process. Specimen 1 has a composition of 7 % aluminum alloy in addition to 1% zinc and the composition of reinforcement is Titanium Carbide 0.3 % in addition to 1.5% Carbon nanotubes. Specimen 2 has a composition of 12 % aluminum alloy in addition to 1 % zinc and the composition of reinforcement is 2% B4C in addition to 2 % Carbon nanotubes. Specimen 3 has a composition of 14 % aluminum alloy in addition to 1 % zinc and the composition of reinforcement is 2 % B4C in addition to 2 % Carbon nanotubes. The mechanical properties analysis showed that specimen 2 has a higher hardness value in comparison to other manufactured specimens and it was also observed that specimen 2 possesses a higher tensile strength value in comparison to the other two specimens. Microstructure analysis shows that there was a uniform distribution of the reinforcements in the matrix. So it can be inferred that this uniform distribution causes higher hardness and higher tensile strength in the manufactured specimens.

661-675

Authors: Selale Elcin Sungur, Umit Turgay Arpacioglu, Mustafa Ozgunler

In this study, London The Shard skyscraper structure was examined under the concepts of sustainability and wind engineering dynamics. The aerodynamic examination of the building in accordance with the wind dynamics principles and the relevant CFD simulations as proof, created. In the simulations carried out in the Matlab CFD environment, the Navier Stokes equation principles with k-omega turbulance model were followed. The skyscraper model 1-1 was created in its original form and simulated under real wind data at its location in London. In the results obtained after the simulations, the velocity increased by V-3V in the first 600-800 meters distance range, in the x direction of the model, created a vortex around the structure. While the speed-vortex effects mechanisms were examined on the model by V-3V, the pressure load P within the first 25 meters in the z direction (structure height) of the model was reached to 5P, up to the limit of 280-300 meters. When it is reached to 300 meters height, a 5-fold increase in pressure was detected. In the x-direction, pressure change of the model tested. The variation of the pressure load at the rate of P - 2P was determined in the first 800-1000 meters of the model in the x-direction, and the pressure exerts a double effect in the first 800-1000 meters of the model. In addition to the norms and regulations of supertall design principles, all risk scenarios of wind, under the effect of velocity and pressure need to be simulated before safe construction.