Journal articles on the topic 'Shells, Concrete – Design and construction'
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Qahorov, K. Q., O. E. Sysoev, and E. O. Sysoev. "Influence of Class of Concrete on Oscillations of Thin-Wall Cylindrical Reinforced Concrete Shells." Materials Science Forum 992 (May 2020): 59–65. http://dx.doi.org/10.4028/www.scientific.net/msf.992.59.
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Thin-walled cylindrical shell made of reinforced concrete, is widely used in the construction of buildings and structures as coatings and forms of architecture of buildings. Thin-walled shell its shape can give entertainment to the architectural design of buildings, and their rigidity helps to block large spans, creating more closure of the room without additional supports. Another advantage of using cloud forms of structures is the efficiency of this design, since for the manufacture of shell forms of structures less construction material is spent than any other design for coating. The purpose of theoretical calculations and the studied excrement over reinforced concrete shells with different elastic modules, is to ensure reliability in the operation of buildings and structures, and to exclude accidents arising resonance phenomena of free vibrations of the shells from the effects of external forces (loads). On the basis of the laboratories of Komsomolsk-on-Amur state University in the laboratory of building materials and structures, experimental studies were conducted to determine the spectra of forced and free vibrations of the reinforced concrete shell with different elastic modules. The purpose of research on reinforced concrete shells is to determine the oscillation frequencies at different locations of the combined masses. The article deals with the theoretical calculation based on the equation of the theory of flat thin-walled shells, using the Bubnov-Galerkin method, by which we determine how the parameters of the shell affect the process of free oscillation.
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Camba, Carolina, José Luis Mier, Luis Carral, María Isabel Lamas, José Carlos Álvarez, Ana-María Díaz-Díaz, and Javier Tarrío-Saavedra. "Erosive Degradation Study of Concrete Augmented by Mussel Shells for Marine Construction." Journal of Marine Science and Engineering 9, no. 10 (October 5, 2021): 1087. http://dx.doi.org/10.3390/jmse9101087.
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This work proposes a green material for artificial reefs to be placed in Galicia (northwest Spain) taking into account the principles of circular economy and sustainability of the ecosystem. New concrete formulations for marine applications, based on cement and/or sand replacement by mussel shells, are analyzed in terms of resistance to abrasion. The interest lies in the importance of the canning industry of Galicia, which generates important quantities of shell residues with negative environmental consequences. Currently, the tests to determine the abrasion erosion resistance of concrete on hydraulic structures involve large and complex devices. According to this, an experimental test has been proposed to estimate and compare the wear resistance of these concretes and, consequently, to analyze the environmental performance of these structures. First, a numerical analysis validated with experimental data was conducted to design the test. Subsequently, experimental tests were performed using a slurry tank in which samples with conventional cement and sand were partially replaced by mussel shell. The abrasive erosion effect of concrete components was analyzed by monitoring the mass loss. It shows an asymptotic trend with respect to time that has been modeled by Generalized Additive Model (GAM) and nonlinear regression models. The results were compared to concrete containing only conventional cement and sand. Replacing sand and/or cement by different proportions of mussel shells has not significantly reduced the resistance of concrete against erosive degradation, except for the case where a high amount of sand (20 wt.%) is replaced. Its resistance against the erosive abrasion is increased, losing between 0.1072 and 0.0310 wt.% lower than common concrete. In all the remaining cases (replacements of the 5–10 wt.% of sand and cement), the effect of mussel replacement on erosive degradation is not significant. These results encourage the use of mussel shells in the composition of concrete, taking into account that we obtain the same degradation properties, even more so considering an important residue in the canning industry (and part of the seabed) that can be valorized.
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Caluk, Nerma, Islam M. Mantawy, and Atorod Azizinamini. "Cyclic Test of Concrete Bridge Column Utilizing Ultra-High Performance Concrete Shell." Transportation Research Record: Journal of the Transportation Research Board 2674, no. 2 (February 2020): 158–66. http://dx.doi.org/10.1177/0361198120906088.
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Ultra-high performance concrete (UHPC) is a durable material that can be used in constructing new and unique structural elements. This research utilizes UHPC to construct prefabricated shells that act as stay-in-place forms for bridge columns and eliminate the use of traditional formwork. These innovative structural elements reduce the on-site construction time, improve the structural performance of the column, and act as a protective layer in aggressive environments. Generally, during the construction process, the prefabricated UHPC shell is placed around the column reinforcement, which is fabricated using conventional methods. To connect the UHPC shell and column reinforcement with the footing and footing dowels, a step made of UHPC is utilized. The UHPC step connection is designed to shift the plastic hinge away from the column-to-footing interface. In the next stage, normal concrete is cast inside the shell, forming a concrete-filled UHPC shell. The final stage of construction involves placing and connecting a prefabricated cap-beam using the same UHPC step connection. The column specimen was tested under constant axial load and incremental lateral load. In this test, the UHPC shell cracked on the north side at a drift ratio of 3%; however, the column had a significant capacity and behaved similarly to a conventional reinforced concrete column during higher cycles of drift ratios. The test was completed after the column had reached a drift ratio of 7.5% when the first bar ruptured. No damage occurred in the footing and UHPC step which proved that the design was successful in shifting the plastic hinge away from the column-to-footing interface.
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Petzoldt, Carolin, Sandra Gelbrich, Meike Röhrkohl, Christian Müller, Johannes Freund, and Lothar Kroll. "Textile Reinforced Lightweight Shells." Materials Science Forum 825-826 (July 2015): 319–27. http://dx.doi.org/10.4028/www.scientific.net/msf.825-826.319.
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Modern architecture is dominated by the tendency to design organically shaped filigree buildings. The resource and energy efficient construction of multifunctional buildings is as important as a broad variety of possible shapes. Multi-material support structures and shell constructions in lightweight design that also take over e. g. lighting and monitoring are needed for these purposes. Textile reinforced lightweight shell structures have been developed at Technische Universität Chemnitz within the scope of research projects. They consist of a hybrid material from carbon-fiber-reinforced concrete and glass-fiber-reinforced plastic. Thanks to the coupling of the positive material characteristics, the combination of two different composite materials results in a hybrid material with a total thickness of 15 mm, which has a high fatigue strength (XF4) and surface quality (exposed concrete). Furthermore, the hybrid is characterized by excellent compressive strength (120 MPa) and bending tensile strength (150 MPa), low susceptibility to corrosion and free formability. Therefore, it is highly suitable for thin-walled filigree lightweight shell structures. A research pavilion with a size of 4 x 4 x 3 m3 (l x w x h), made from textile reinforced lightweight shells, was built on the campus of TU Chemnitz, to test the theoretical investigations. Specially developed tensile sensors for the active lighting and determination of the elongations were integrated into the different layers. This aimed at an online-monitoring of the shell support structure.
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Moreyra Garlock, Maria E., and Branko Glisic. "Thin Shell Concrete Structures of Félix Candela and Max Borges Jr." Journal of the International Association for Shell and Spatial Structures 61, no. 1 (March 1, 2020): 51–58. http://dx.doi.org/10.20898/j.iass.2020.203.031.
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Max Borges Jr. (1918 – 2009) was an architect of thin shell concrete structures in Cuba in the 1950's. During this time, Félix Candela (1910 – 1997) owned a construction company that was dedicated to the design and construction of thin shells. Candela also owned an international reputation as a designer of thin shells in the hyperbolic paraboloid (hypar) form. The two men worked together for the first time on a project in Mexico City in 1954, and since then collaborated on several more, most of them in Cuba. This paper illustrates the architect – engineer relationship between Borges and Candela and documents the collaborative projects between them. The research grew out of a course co-taught by the authors, where the course was inspired by the style of teaching of David Billington (1927 – 2018) that integrates engineering with the humanities. Billington believed in scholarship based on historical studies and documentation of heritage structures. This paper is in tribute to this great man who continues to inspire.
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Kovářík, Michal, Pavel Svoboda, and Henri Hubertus Achten. "Limits and Potential of 3D Printing Technologies for Construction of Concrete Shells." Solid State Phenomena 292 (June 2019): 249–56. http://dx.doi.org/10.4028/www.scientific.net/ssp.292.249.
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Concrete shells are a very effective type of building structures due to their ability to bridge large spans with minimal construction thickness. This type of building structures built on the medieval vaulting techniques and, regarding the use of reinforced concrete over the last 100 years, it has overcome the limitations of the masonry vaulting technologies and enabled to increase the span of structures to tens of meters. The construction technology to realize concrete shells using monolithic casting into formwork is besides abovementioned advantages characterized by high labour and thanks to the cost and manufacturing intensity of double curved formwork panels it allows economical realization of only selected structural geometries. Its considerable limitation is, besides the costly production of double curvature formwork, also the laborious installation of formwork and falsework structures. The solution seems to be in line with the upcoming transition to Construction 4.0 robotizing the construction technology of shells that could create a similar increase in productivity and design possibilities as was the technological transition between vaults and shells. One of the promising technologies of robotic production seems to be digital fabrication methods and, in particular, 3D printing or in other words additive manufacturing. This wasteless technology, which has been used to date for experimental projects mainly for the realization of vertical bearing structures, has, despite the first attempts at realizing vaults, a number of technological limitations. In this article, authors aim to summarize and indicate possible constraints of on site 3D printing of domes. They further indicate the possible ways to overcome these limitations and suggest two different means of on site 3D printing of hemispherical dome and the dome based on the catenary profile using extrusion nozzles with different profiles. Finally they discuss the Eurocode requirements for concrete shells and suggest technological solutions for on site 3D printed shells in terms of structural reinforcement.
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Krivoshapko, Sergey N. "Shell structures and shells at the beginning of the 21st century." Structural Mechanics of Engineering Constructions and Buildings 17, no. 6 (December 30, 2021): 553–61. http://dx.doi.org/10.22363/1815-5235-2021-17-6-553-561.
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Researchers know that golden century of shells falls on 1920-1960 when the finishing of building of a thin-walled shell became an important event in life of country where this shell was erected. Every built shell was analyzed in tens of scientific works with a point of view of used method of analysis, applied constructive materials, cost of erection. Later on, an interest to thin-walled shells fell down. On the base of the fulfilled research in a paper, it is shown that application of shell structures is increasing in the 21st century because it was closely connected with needs of different branches of human activity. It is proved, that practically in all countries of the world, design and building of shell structures and shells was carried out. Only priority in application constructive materials changed. In the main, reinforced concrete was used earlier but now bar curvilinear structures, composite shells, and bar structures with the glass filling are in priority. It is shown that young and prominent architects and engineers tale part in construction of considered structures and thin-walled shells. All conclusions are confirmed by references containing 38 used original sources.
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Schnobrich, William C. "Design and construction of concrete shells, G. S. Ramaswamy, Robert E. Krieger Publishing." International Journal for Numerical Methods in Engineering 23, no. 4 (April 1986): 731. http://dx.doi.org/10.1002/nme.1620230415.
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Vasudevan, Gunalaan, Hidayu Murni Abu Hussain, Noor Aina Misnon, and Faridah Hanim Khairuddin. "Effect of Alum Sludge (AS) and Palm Kernel Ash (PKA) with Coconut Shell as Partial Replacement of Aggregates." Materials Science Forum 1077 (December 15, 2022): 251–56. http://dx.doi.org/10.4028/p-7lp1b2.
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At present, there is a high demand for concretes with varying properties. Generally, concrete with high durability can be produced by considering the constituents of the concrete, such as cement, sand, aggregates, and water. The quality of concrete is also dependent on the mix design and production method, such as transporting and pouring of concrete. In recent years, the developed countries have been focusing on the issue of sustainability in construction to create a healthier environment and reduce the environmental impact of a building throughout its lifetime while optimizing its economic viability and ensuring the comfort and safety of the occupants. One way to achieve sustainability is using agricultural waste material such as palm oil fuel ash, rice husk, fly ash slag, sludge, and coconut shell in concrete production. This study performs a series of tests to investigate the effect of using alum sludge (AS) and palm kernel ash (PKA) with coconut shells as a partial replacement of aggregates. The concrete samples were subjected to compressive strength, flexural strength, rebound hammer, ultrasonic pulse velocity, water permeability, water absorption, carbonation, alkali-silica reaction, SEM, and shrinkage tests.
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Gonzalez, Edwin, Giancarlo Di Marco, Cynthia Gonzalez, and Jessica Galindo. "Parametric Analysis of the Dome of the Sports Palace of Mexico City." Journal of the International Association for Shell and Spatial Structures 62, no. 1 (March 1, 2021): 50–60. http://dx.doi.org/10.20898/j.iass.2021.004.
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The Sports Palace of Mexico City was built in 1968 and became a turning point in the design and construction of laminar shells, leading the transition from reinforced concrete to metallic grid structures. Felix Candela observed that the use of concrete in designing laminar structures was limited to achieve great spans for sport spaces; he thus changed his first proposal for using a concrete laminar shell to a metallic structure. However, in the first architectural conception of the metallic structure, a lighter cable structure was proposed respecting the built geometry, with the intent of using high-strength wires in the upper and lower chords of the arches. In this paper, three different proposals are modeled. The first uses a 3D modelled concrete shell for understanding the geometry. The others use the final geometry and are analyzed using advanced NURBS (Non-uniform rational Bspline) modeling techniques with Rhinoceros and a parametric design with Grasshopper, where the parameters and results obtained in previous tests are compared with the results obtained in the simulations. Paneling plugins, forces simulation add-ons, finite elements analysis and environmental design simulation tools in Grasshopper are used to compare the results under normal design conditions.
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Nadh, V. Swamy, Chunchubalarama Krishna, L. Natrayan, KoppulaMidhun Kumar, K. J. N. Sai Nitesh, G. Bharathi Raja, and Prabhu Paramasivam. "Structural Behavior of Nanocoated Oil Palm Shell as Coarse Aggregate in Lightweight Concrete." Journal of Nanomaterials 2021 (October 1, 2021): 1–7. http://dx.doi.org/10.1155/2021/4741296.
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Oil palm shells (OPS) are mechanical waste that is utilized as coarse aggregates in lightweight concrete. These OPS have shape and strength like conventional aggregates yet the substantial made with these OPS invigorates a limit of 18 MPa. The characteristic strength which must be utilized in structures is seen to be around 25 MPa to 30 MPa. Considering the strength as one of the boundaries for design to be sturdy, the OPS are surface-covered with nanosilane compound. This nanosilane covering goes about as infill on the outside of the aggregates and holds the concrete paste as traditional cement. Operations are permeable in nature; their inner construction has permeable design which makes the aggregates frail. Nanosilane coatings go about as holding between the concrete stage and aggregate stage and hold the substantial solid. In the present examination, mechanical and underlying conduct of nanocovered oil palm shell lightweight concrete is contrasted with that of regular cement. Nanocovered oil palm shell lightweight substantial shows comparative strength as customary cement and decrease in nonsustainable wellspring of energy in oil palm shell lightweight concrete. Supplanting of customary cement with oil palm shell concrete addresses the modern waste which can be utilized for making concrete solid and solid. Morphology and material portrayal of oil palm shell and ordinary aggregates are investigated.
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Fenu, Luigi, Eleonora Congiu, Giuseppe Carlo Marano, and Bruno Briseghella. "Shell-supported footbridges." Curved and Layered Structures 7, no. 1 (November 9, 2020): 199–214. http://dx.doi.org/10.1515/cls-2020-0017.
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AbstractArchitects and engineers have been always attracted by concrete shell structures due to their high efficiency and plastic shapes. In this paper the possibility to use concrete shells to support footbridges is explored. Starting from Musmeci’s fundamental research and work in shell bridge design, the use of numerical form-finding methods is analysed. The form-finding of a shell-supported footbridge shaped following Musmeci’s work is first introduced. Coupling Musmeci’s and Nervi’s experiences, an easy construction method using a stay-in-place ferrocement formwork is proposed. Moreover, the advantage of inserting holes in the shell through topology optimization to remove less exploited concrete has been considered. Curved shell-supported footbridges have been also studied, and the possibility of supporting the deck with the shell top edge, that is along a single curve only, has been investigated. The form-finding of curved shell-supported footbridges has been performed using a Particle-Spring System and Thrust Network Analysis. Finally, the form-finding of curved shell-supported footbridges subjected to both vertical and horizontal forces (i.e. earthquake action) has been implemented.
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Andriichuk, О. V., and S. O. Uzhehov. "THE FRACTURE TOUGHNESS OF THIN-WALLED COVER SHELLS HYPERBOLIC PARABOLOID SHAPED OF FERROCEMENT AND STEEL FIBER CONCRETE UNDER THE ACTION OF OPERATING LOADS." Ресурсоекономні матеріали, конструкції, будівлі та споруди, no. 37 (January 30, 2020): 89–96. http://dx.doi.org/10.31713/budres.v0i37.334.
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Experimental research of new materials and structures with improved parameters of strength, fracture toughness, bearing capacity and their lifetime in comparison with typical elements is an actual problem of building science.Nowadays there is a trend to design and use for buildings covering the new design solutions as the thin shells. One of the types of thin shells are Gaussian shells with negative curvature. It’s worth to note that in the last decade, a considerable number of researches of thin-walled structures made of steel fiber reinforced concrete were conducted, which confirmed the efficiency of its use to enhance their hardness, fracture toughness and thus longer life.The article presents the results of the authors’ experimental studies of fracture toughness of thin-walled cover structures with Gaussian negative curvature in the shape of hyperbolic paraboloid made of ferrocement and steel fiber reinforced concrete under the action of the operating load.The load application was carried out for ten steps, after each step the pause was for 15...20 min, during which the data of the strain-gauge station VNP-8 was recorded, using a microscope were measured and recorded the width of the cracks, deflections of the structure were measured etc.The external force was evenly-distributed to its applications and the impact was simulated according to the real conditions of construction use.The experimental part of the research was conducted at the laboratory of building materials and structures of Lutsk National Technical University. In scientific work carried out mapping and comparison of the obtained experimental results, carried out processing and analysis, presents the conclusions.During the researches it was found that the fracture toughness of thin-walled shell cover with Gaussian negative curvature in the shape of a hyperbolic paraboloid with dispersed reinforcement (steel fiber reinforced concrete) is higher than in the shell made of ferrocement. Accordingly, it can be argued about the increasing of the lifetime of steel fiber reinforced concrete shell covering in comparison with the ferrocement shell.
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Wagner, Rosemarie, and Annette Bögle. "Double-Curved Space Structures – Function and Construction." International Journal of Space Structures 17, no. 2-3 (June 2002): 117–27. http://dx.doi.org/10.1260/026635102320321761.
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Efficient double curved structures like reinforced concrete shells, membrane- and cable-net-structures are less well represented in contemporary structural engineering. To apply these structures sensibly in practice, dominated by short planning phases, rapid construction and tremendous financial pressure, an in-depth knowledge of these complex structures is needed. Dealing with large open areas and three-dimensional shapes requires an extensive insight already during the design-process with creative freedom being restricted by technical and economical as well as functional and aesthetical aspects, due to the relationship between shape, function and structure.
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Krivoshapko, SN. "Static, vibration, and buckling analyses and applications to one-sheet hyperboloidal shells of revolution." Applied Mechanics Reviews 55, no. 3 (May 1, 2002): 241–70. http://dx.doi.org/10.1115/1.1470479.
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The principal achievements of science and engineering in the sphere of design, construction, and static, vibrational, and buckling analysis of thin-walled constructions and buildings in the shape of hyperbolic surfaces of revolution are summarized in this review article. These shells are useful as hyperbolic cooling towers, TV towers, reinforced concrete water tanks, and arch dams. They are also used as supports for electric power transmission lines and as high chimneys. Several public and industrial buildings having the hyperbolic form are described in the review. The basic results of theoretical and experimental investigations of stress-strain state, buckling, and vibration are summarized. The influence of temperature and moisture on the stress-strain state of the shells in question is also analyzed. This review article contains 261 references.
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Tsai, Meng Ting, Chung Hsien Shih, Yu Chun Lin, and Chia Chi Cheng. "Inspection of Hyperbolic Reinforced Concrete Shells-Luce Memorial Chapel-Based on Nondestructive Testing Method." Key Engineering Materials 735 (May 2017): 113–18. http://dx.doi.org/10.4028/www.scientific.net/kem.735.113.
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This paper is aimed to inspect the chapel’s overall structural system based on nondestructive testing (NDT), and a rebound hammer test and a ground-penetrating radar (GPR) system are employed to conduct a nondestructive testing. It is important before the chapel’s structural performance was assessed, the structure was inspected to investigate the current state and was constructed according to its original structural designs. According to the inspection, it is found the concrete compressive strength of all the components is larger than the original design strength. Moreover, the total numbers of the reinforcing bars of Slabs S1 and N1 are consistent with the number in the original design (246). However, the total numbers of the reinforcing bars of Slabs S2 and N2 are 167 and 174, respectively, whereas those of the original design were 150, indicating additional vertical reinforcing bars were applied in the chapel’s construction. Based on the results of inspection, the future structural performance assessment and retrofitting are expected to be set-up properly.
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Ivaniuk, Egor, Irina Ivanova, Dmitrii Sokolov, Zlata Tošić, Martin Friedrich Eichenauer, Daniel Lordick, and Viktor Mechtcherine. "Application-Driven Material Design of Printable Strain Hardening Cementitious Composites (SHCC)." Materials 15, no. 5 (February 22, 2022): 1631. http://dx.doi.org/10.3390/ma15051631.
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The creation of concrete shells from customized prefabricated modules is a novel approach that facilitates the construction of free-form surfaces considerably. In the framework of the Adaptive Concrete Diamond Construction (ACDC) project at TU Dresden, a material for 3D printing of the outer contours of such modules has been developed based on the principles of Strain Hardening Cementitious Composite (SHCC). In addition to its high ductility, the required material must also be suitable for 3D printing while enabling the achievement of high geometric accuracy in the manufacture of the modules. To gain the required performance, cellulose ether and starch ether were used specifically to extend the open time, for a longer period of maintaining initial workability, as well as for enhancing shape stability and surface quality. An extensive experimental program was carried out to evaluate the outcomes of the material modifications, including flow table tests, water retention tests, and several specific tests to determine the adhesiveness of the fresh SHCC. For hardened SHCC, surface roughness was assessed using a laser 3D scanner in addition to testing its mechanical properties.
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Li, Yang Eileen, Liang Guo, Biljana Rajlic, and Philip Murray. "Hodder Avenue Underpass: An Innovative Bridge Solution with Ultra-High Performance Fibre-Reinforced Concrete." Key Engineering Materials 629-630 (October 2014): 37–42. http://dx.doi.org/10.4028/www.scientific.net/kem.629-630.37.
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The Hodder Avenue underpass – recipient of the Precast/Prestressed Concrete Institute (PCI)’s Harry H. Edwards Industry Advancement Award – is a new highway bridge near Thunder Bay, Canada that utilized a modular construction approach facilitated by the extensive use of ultra-high performance fibre-reinforced concrete (UHPFRC) to expedite construction, elevate aesthetic value and enhance quality and durability. Almost all structural components were precast in facilities and assembled on site using UHPFRC joints, which have compact geometries with less complexity, superior durability and strength. The precast elements include a unique UHPFRC pier cap and pier column shells, high performance concrete (HPC) box girders, sidewalks/parapet walls, abutment caps, ballast walls, slope paving panels and approach slabs. Aesthetically, the structure achieved a slender and open form with the use of shallow precast box girders and a unique pier cap visually and structurally integral with the superstructure. The cap beam was prestressed and precast fully with UHPFRC to overcome design challenges such as geometrical limitations and complex loading. The pier cap and girders were made composite using field-cast UHPFRC joints reinforced with stainless steel bars and threaded bolts. The pier columns also utilized a unique design with precast UHPFRC shells serving as an aesthetic stay-in-place form as well as a protective layer for the salt splashes during Thunder Bay’s harsh winter seasons.
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Schleicher, Simon, and Michael Herrmann. "Constructing hybrid gridshells using bending-active formwork." International Journal of Space Structures 35, no. 3 (June 16, 2020): 80–89. http://dx.doi.org/10.1177/0956059920924189.
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Aiming to promote a more sustainable approach to material utilization in architecture, this article presents an alternative construction method for lightweight and efficient concrete structures. The strategic focus is placed on building wide-spanning roof structures like vaults, domes, and freeform shells with the lowest possible input of raw materials and energy. To achieve this objective, the article explores the novel idea of using bending-active structures, made from millimeter-thin carbon fiber strips, as lost formwork and structural reinforcement for the production of hybrid gridshells. After a general introduction to the state-of-the-art in concrete construction, the authors discuss opportunities and challenges related to flexible formwork designs and their possible impacts on the building industry. Relying on the example of a built prototype, the authors present a promising design methodology and analyze the gridshell’s geometrical and structural characteristics throughout different stages of the construction process. The article concludes by discussing the added value of this research and identifying the key aspects that need to be considered in the further development of this construction method.
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Ostovari, Shadi, and Hooman Shayani. "Effect of the number of design variables in thickness optimization of concrete barrel roof shells using evolutionary algorithms." International Journal of Space Structures 34, no. 3-4 (September 2019): 74–84. http://dx.doi.org/10.1177/0956059919893212.
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This study looks into some practical implications of using evolutionary algorithms for optimization of free-form concrete shells in search of methods for automating design representation and determining the number of design variables. This study reports the insights and learnings from a set of numerical experiments, by changing the number of parameters, on thickness optimization of a barrel roof shell subjected to self-weight, an additional snow load, and an earthquake response spectrum. The practical advantages and challenges of two methods, parametric and direct representations, are analysed, and a spectrum of methods between these two extremes are investigated through experiments. The results demonstrate how changing the number of variables affects the quality of the design and the performance of the algorithm and why a systematic problem-dependent method for finding the best design representation and number of variables outside this spectrum can be beneficial.
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Inzhutov, Ivan, Victor Zhadanov, Maxim Semenov, Sergei Amelchugov, Alexey Klimov, Peter Melnikov, and Nadezhda Klinduh. "A comparative analysis of foundation design solutions on permafrost soils." E3S Web of Conferences 110 (2019): 01019. http://dx.doi.org/10.1051/e3sconf/201911001019.
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The article analyzes design solutions of foundations on permafrost soils, their advantages and disadvantages. Innovative design solutions that increase the energy efficiency of buildings are proposed. Examples of innovative foundations of platform type are given. Spatial ventilated foundations are less sensitive to soil deformation. The construction of such a foundation can be made of various materials such as reinforced concrete, metal and timber. A spatial foundation platform based on timber is proposed as one of the innovative examples, which is a promising constructive solution of foundations for construction in the Arctic regions. Wood has a small coefficient of thermal conductivity, which significantly increases the energy efficiency of the structure as a whole. Due to prefabrication of timber structures, the speed of construction is increased. Platforms can have solutions in the form of: system of cross beams, structural plates, plate-rod structure, as well as in the form of shells and folds. Regardless of the design solution, the spatial foundation platform is prefabricated.
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Сысоев, Евгений Олегович, Комилджон Кахорович Кахоров, Олег Евгеньевич Сысоев, and Екатерина Викторовна Журавлева. "Examination of free and forced oscillations of open thin-wall reinforced concrete shells." Вестник Чувашского государственного педагогического университета им. И.Я. Яковлева. Серия: Механика предельного состояния, no. 1(43) (March 27, 2020): 121–30. http://dx.doi.org/10.37972/chgpu.2020.43.1.013.
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Тонкостенные цилиндрические оболочки, выполненные из железобетона, широко используется в качестве покрытий зданий и сооружений. Тонкостенные оболочки могут перекрывать большие пролёты и создавать большие закрытые помещения без дополнительных опор, обладают оптимальной формой и хорошими технико-экономическими показателями. В настоящее время при проектировании зданий и сооружений не производятся специальные расчёты на возникновение резонансных явлений, отсутствуют расчетные модели и недостаточно экспериментальных данных. При этом тонкостенные оболочки очень чувствительны к внешним воздействиям (ветровые и снеговые нагрузки), вызывающие вынужденные колебания, которые приводят к разрушению конструкции. К примеру, в 2004 г. трагедия в «Трансвааль-парке» г. Москва унесла жизни 28 человек, более 100 получили ранения; в 2010 г. на стадионе в Миннесоте (США) обрушилась одна из секций крыши, завалив трибуну; в 2015 г. авария строящегося резервуара на нефтезаводе в г. Комсомольске-на-Амуре, возникшая из-за колебаний от ветровых нагрузок; в 2015 г. кровля крытого катка (с. Верх-Ирмень Новосибирской обл.) не выдержала совместных ветровых и снеговых нагрузок; в 2017 г. произошел обвал крыши школы в п. Мурино; в 2018 г. деформации крыши строящегося катка г. Истра носили катастрофический характер. Целью теоретических расчетов и проведения экспериментов с железобетонными оболочками с разными модулями упругости заключается в обеспечении надежности при эксплуатации здания и сооружения и исключения аварийных ситуаций, возникающих при резонансных явлениях свободных колебаний оболочек от воздействия внешних сил (нагрузок). В статье приведены результаты экспериментальных исследований по определению спектров вынужденных и свободных колебания, частот и форм колебаний разомкнутых оболочек от внешних воздействий. Рассматривается теоретический расчёт разомкнутой оболочки на основе уравнений теории пологих тонкостенных оболочек с использованием метода Бубнова-Галеркина, с помощью которого определены влияние параметров оболочки на процессы свободного колебания. Получены данные зависимости спектра колебаний от класса бетона - из этих результатов можно сделать вывод, что с увеличением класса бетона уменьшаются средние показатели частот колебания, а первоначальные показатели частот колебаний почти затухают. Thin-walled cylindrical shells made of reinforced concrete are widely used as coatings of buildings and structures. Thin-walled shells can cover large flights and create more closure of the room without additional supports, with optimal shape and good techno-econmic indicators. At present, the design of buildings and structures does not make special calculations for the occurrence of resonance phenomena, absence of design models and insufficient experimental data. At the same time thin-walled shells are very sensitive to external effects (wind and snow loads) causing forced fluctuations, which lead to the destruction of the structure. For example in 2004 tragedy in Transvaal Park in Moscow killed 28 people, more than 100 were injured; in 2010, a roof section collapsed at a stadium in Minnesota, United States, collapsing the podium; in 2015, an accident at the Komsomolsk-on-Amur oil plant under construction caused by fluctuations from wind loads; in 2015, (Top-Irmen of Novosibirsk region) roof of the covered rink failed to withstand joint wind and snow loads; in 2017, the roof of a school in Murino village collapsed; in 2018, the deformation of the roof of the Istra rink under construction was catastrophic. The purpose of theoretical calculations and carrying out excreta with reinforced concrete shells with different modules of elasticity is to ensure reliability during operation of the building and structure, and to avoid accidents, arising resonance phenomena of free oscillations of shells due to external forces (loads). The article presents the results of experimental studies on determination of spectra, forced and free oscillations of reinforced concrete shell with different modules of elasticity. The whole, carrying out research of reinforced concrete shells is determination of frequencies and form of oscillation of open shells due to external effects. The paper considers the theoretical calculation of the open shell based on the equations of the theory of shallow thin-walled shells, using the Bubnov- Galerkin method, by which we determine how the parameters of the shell affect the processes of free oscillation. After the studies, the data of the vibration spector dependence on the concrete class are obtained, with the help of these results it can be concluded that as the concrete class increases, the average values of the oscillation frequencies decrease, and the initial values of the oscillation frequencies almost fade.
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Umasabor, R. I., and J. O. Okovido. "Investigation of the Compressive Strength and Curing Duration of Binary Blend of Groundnut Shell Ash Concrete." Nigerian Journal of Environmental Sciences and Technology 1, no. 1 (March 2017): 75–80. http://dx.doi.org/10.36263/nijest.2017.01.0032.
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This paper studied the evaluation of the compressive strength of the binary blend of groundnut shell ash concrete and curing period. The purpose of the study was to source for local materials like agricultural waste that could replace some percentages of cement in order to make it more economical in concrete in order to ascertain its usefulness in the construction industry. An experimental (quantitative) method was adopted as the research design in this work. The total concrete specimens of size 100mm x100mm produced in the laboratory were one hundred and twenty (120). The groundnut shells were completely burnt in an electric furnace to obtain the ash and 0%, 5%, 10% and 15% of the ashes were used to replace cement for a designed mix of concrete strength of 20N/mm2 at w/c ratio of 0.6, after varying the w/c ratios from 0.4 to 1.0, according to basic guidelines stated in Department of Environment method. They were cured at 7 days, 28 days, 30 days, 60 days, 90 days, 120 days, 150 days and 200 days. The concrete cubes were taken to the compression machine for compression test. The result shows that compressive strength of the groundnut shell ash concrete increases as the curing period increases and there was decrease in the compressive strength of the pozzolanic concrete as the percentages of groundnut shell ash increases in the concrete. The binary blend of groundnut shell ash at 5% replacement had the maximum compressive strength of 23.3N/mm2 at 200 days while the control concrete compressive strength was 22.0N/mm2. This represents an increment of 1.06% of compressive strength over the control at 200 days.
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SILVA, R. L. C., G. B. MARQUES, E. N. LAGES, and S. P. C. MARQUES. "Analytical study of cylindrical tanks including soil-structure interaction." Revista IBRACON de Estruturas e Materiais 12, no. 1 (February 2019): 14–22. http://dx.doi.org/10.1590/s1983-41952019000100003.
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Abstract An analytical study aiming the design of cylindrical liquid storage tanks resting on deformable foundations is developed in this work. The soil under the tanks is modeled as an elastic linear medium. The cylindrical wall is considered rigidly connected to the plate foundation. Here, concrete tanks are emphasized, although the study can be extended to other construction materials. For the analysis of the design forces acting on the tanks, efficient and simplified approximate expressions are derived based on rigorous analytical theories for thin shells and circular plate on elastic foundations. To verify the proposed approximate expressions and investigate the influence of the foundation deformability on displacements and design forces, parametric analyses of concrete tanks with different soil stiffness values are presented. The results illustrate the strong influence of the foundation stiffness on the tank design quantities and a very good performance of the simplified expressions.
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Krivoshapko, S. N. "Research on General and Axisymmetric Ellipsoidal Shells Used as Domes, Pressure Vessels, and Tanks." Applied Mechanics Reviews 60, no. 6 (November 1, 2007): 336–55. http://dx.doi.org/10.1115/1.2806278.
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The principal advances in the design and construction, as well as the static, vibrational, and buckling analysis of thin-walled structures and buildings in the shape of general and axisymmetric ellipsoidal shells are summarized in this review. These shells are particularly useful as internally pressurized vessels or as heads and bottoms of cylindrical tanks and vessels. Reinforced concrete and structural steel domes of buildings, air-supported rubber-fabric shells, and underwater pressure vessels are also made in the form of ellipsoidal, shells. Knowing the geometry of ellipsoids, one can solve various problems in physics, optics, and so on. Basic results of theoretical and experimental investigations of the stress-strain state, buckling, and natural and forced vibrations contained in 209 references are presented in the review. The influence of temperature on the stress-strain state of the shells in question is also discussed. Some parts of the review are also devoted to an analysis of the literature on the stress-strain state of ellipsoidal and torispherical heads of pressure vessels with openings.
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Méndez Echenagucia, Tomás, Dave Pigram, Andrew Liew, Tom Van Mele, and Philippe Block. "A Cable-Net and Fabric Formwork System for the Construction of Concrete Shells: Design, Fabrication and Construction of a Full Scale Prototype." Structures 18 (April 2019): 72–82. http://dx.doi.org/10.1016/j.istruc.2018.10.004.
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Ponomarev, Andrei B., V. I. Kleveko, O. V. Moiseeva, and K. R. Kashapova. "FIBER REINFORCED SAND BACKFILL FOR UNDERGROUND PEDESTRIAN CROSSINGS." Acta Polytechnica CTU Proceedings 10 (October 15, 2017): 34. http://dx.doi.org/10.14311/app.2017.10.0034.
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Crosswalk is an essential element of the transport system of any city. A priority assignment in any such crossing is to ensure the safety of pedestrians. Underground pedestrian crossings are much safer than crossings at another level, but they lose in attraction when it comes to cost. The cost of the construction of an underground pedestrian crossing often leads to project abandonment. The cost of construction can be reduced through the use of flexible corrugated metal structures instead of ordinary concrete structures. The stress-strain state of the structural shells need to be known to facilitate their rational design. The stress-strain state of flexible corrugated metal shells largely depends on the strength and deformation characteristics of the surrounding soil. Therefore, improving the characteristics of backfill soil is an urgent task in reducing the cost of construction for such tunnels. One way to improve the strength and deformation characteristics of soils is the use of reinforcement. Currently, there are a large number of reinforcement schemes and also associated reinforcing materials. One of the most prospective methods of soil reinforcement is the use of fibre filaments. Fibre reinforced soils have significantly higher strength and deformation characteristics in comparison with unreinforced soils. Numerical modelling of a tunnel shell made out of a corrugated metal structure was undertaken to evaluate the effectiveness of using fibre reinforced sand. Ordinary sand and sand reinforced with polypropylene fibres have been used as soil backfill. The calculation results for a pedestrian tunnel structure involving different strength and deformation characteristics of the backfill soil are presented in this article.
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Elansary, Ahmed A., Ashraf O. Nassef, and Ashraf A. El Damatty. "Optimum design of composite conical tanks under hydrostatic pressure." Advances in Structural Engineering 21, no. 13 (March 23, 2018): 2030–44. http://dx.doi.org/10.1177/1369433218764976.
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Elevated tanks are used all over the world to store water for times of shortage. These tanks can be made of steel, reinforced concrete, or composite, that is, concrete and steel. Composite tanks consist of an external steel shell attached to an internal reinforced concrete wall through steel studs. Composite conical tanks combine the advantages of reinforced concrete and steel tanks as they resist efficiently both tensile and compressive stresses. A comparison showed that the material cost of composite conical tanks is significantly less than that of steel or reinforced concrete tanks having the same layout dimensions. A numerical tool is developed to obtain the optimum design of composite conical tanks under hydrostatic pressure incorporating both finite element and genetic algorithm techniques. This tool is used to obtain the optimum design of a case study composite conical tank that was recently constructed. The developed optimization tool provides the thicknesses of the concrete and steel walls as well as the stud configuration corresponding to the minimum material cost. A comparison between the optimized and unoptimized case study composite tank revealed that a reduction of 32% in the material cost can be achieved. A sensitivity analysis is conducted by changing the price of concrete, steel plate, and studs by (±) 50% of the datum prices and obtaining the corresponding optimum design variables. This analysis showed that the optimum thicknesses of the concrete wall and steel shell as well as studs’ configuration are significantly sensitive to the change in the material prices.
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HLADYSHEV, Hennadii, Dmytro HLADYSHEV, and Roman ZHURAVLOV. "ESTIMATION OF VARIABILITY OF STEPS OF ARMATURE IN A MONOLITHIC REINFORCED CONCRETE COVER OF A TOWER INDUSTRIAL CONSTRUCTION." Building constructions. Theory and Practice, no. 9 (December 28, 2021): 45–53. http://dx.doi.org/10.32347/2522-4182.9.2021.45-53.
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The work considers one of the possible reasons for reducing the operational reliability of monolithic thin-walled load-bearing reinforced concrete structures of existing industrial structures in relation to their design solution. As this reason is considered the variability of distances between axes of cores of working inspectedarmature of such designs is quite common.Comparison of design solutions with the qualityof construction and installation work makes it possible to identify the influence of unaccounted factors in the design of monolithic thin-walled reinforced concrete structures, which reduce their serviceability due to variability of concrete strength characteristics and actual longitudinal and transverse reinforcement due to variability of workingsteps. While processing the results of the survey ofmonolithic reinforced concrete thin-walled structures, which perceive the efforts of different levels,the question arises: which step of the working reinforcement, from a large number of actually measured steps, to choose in verified calculations –average or maximum, with extras.In the current norms, an indicator as the averagevalue of concrete strength for the calculation ofreinforced concrete monolithic slab structures doesnot appear, but is used as a statistically reasonablevalue of concrete strength, which takes into account its normalized variability with 95% security.Regulatory documents statistically estimates thevariability of reinforcement strength. At the sametime, they do not take into account the variabilityof the actual reinforcement of monolithic reinforced concrete structures, which is the subject forreconstruction of additional loads, but they aremade without observing the design distances between the reinforcement in these structures.When performing verified calculations of suchstructures for different design situations, to develop working designs for overhaul, reinforcement,reconstruction or dismantling, it is necessary todetermine which actual step of the working reinforcement should be taken with other defined design parameters of the structure.The authors instrumentally investigated and statistically analyzed the data of reinforcement of themonolithic reinforced concrete shell of the towerstructure, which made it possible to reasonablyaccept the values of the reinforcement steps in thetest calculations.
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Rochman, Taufiq, and Suhariyanto. "STATE OF THE ART OF TANK STRUCTURAL EVALUATION REVIEW: A CASE STUDY OF AN ELEVATED CONCRETE WATER TANK CONCERNING CRACK INITIATION." Journal of Southwest Jiaotong University 56, no. 5 (October 30, 2021): 90–106. http://dx.doi.org/10.35741/issn.0258-2724.56.5.9.
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This study aims at the structural evaluation of the elevated concrete water tank condition, including crack initiation, through nondestructive testing. The growing demands for environmental quality have resulted in a rise in the design and construction of tanks and reservoirs in the construction industry. Cracks for water line leakage were found during watertight testing in concrete tanks. Long-term liquid leaking may permanently damage the tank and can contaminate the groundwater. Given the critical existence of leaked cracks in tank serviceability and durability, the contribution examines the triggers and effects of their occurrence. An inspection of the existing water tank system is conducted to ascertain its condition. The investigation included structural design checks, concrete compressive strength tests, visual assessments, hammer inspections, and Ultrasonic Pulse Velocity (UPV) testing with Portable Ultrasonic Non-Destructive Digital Indicating Tester (PUNDIT). This observation is made at many elevations on various sampling points on the tank structure's elements, including columns, beams, tank floor slabs, and tank wall shells. The results indicate the presence of flexural type cracks in the main beam's middle span and diagonal beams. Additionally, cracks attributed to long-term drying shrinkage were discovered on the diagonal of the floor slab and cracks of the same pattern on the main beam's middle span. The deflection estimated by structural remodeling was larger than the deflection estimated by design. The computed crack width in the main and diagonal beam exceeds the acceptable crack width.
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O'Brien, Gerry, and Nicolas Sterling. "The structure of the Grand Theatre de Rabat, Morocco: from digital design to local construction." Structural Engineer 98, no. 6 (June 1, 2020): 28–40. http://dx.doi.org/10.56330/ytjx6904.
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This paper describes the structural design, from concept to delivery, of the Grand Theatre de Rabat in Morocco. The project includes an 1800-seat theatre, a large open-air amphitheatre, secondary experimental performance and rehearsal spaces, and a panoramic restaurant. It forms part of a national programme of cultural development located on the Bouregreg River between the ancient twin cities of Rabat and Salé. The complex nature of the programme and the form demanded an advanced digital process for the structural design. The most prominent example of the 3D process is the structural envelope wrapping around the entire building. Its concrete skin is stiffened by a regular grid of ribs, rationalised, but following the complexity of the shape and spanning in an efficient way that provides a continuous system, together with the concrete roof deck, to support the facade cladding. A highly automated parametric workflow was set up to create the geometry of the concrete ribs and shell, closely derived from the architectural design. The concrete ribbed shell and roof envelope went through an iterative process of rationalisation, informed by constructability constraints. The fabrication and delivery of the Grand Theatre de Rabat has been both a technical and a cultural challenge, with a London-led, digitally driven design process bridging to a local, traditional, analogue construction process.
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Parthiban, D., D. S. Vijayan, Sachu andrews, Sangsangrach sangma, and Arif mohammed. "Study on Engineering behavior of conventional cement concrete by partially replacing sea shell as Fine aggregate." Journal of Physics: Conference Series 2040, no. 1 (October 1, 2021): 012036. http://dx.doi.org/10.1088/1742-6596/2040/1/012036.
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Abstract In this study, it was investigate about the engineering behavior of conventional concrete of grade M25, by replacing the fine aggregate by partially with crushed sea shell. On because of progression in the field of infrastructure, the dearth of construction material becomes upsurge day by day. All the investigator was observe to find the substitute construction materials to meet the demand of construction in world wide. The reason behind is, while continuous utilizing of the natural raw material for construction decline the resource of those materials and further, it leads to affect the routine function of the earth and made drastic change in the life cycle of living beings. Therefore, it is obvious to find out the possible alternative material to suit for all type of construction. In this study, the sea shell was used as a fine aggregate in the method of crushed powder in an apparent proportion such as 10%, 20% and 30% replacing in the place of fine aggregate sand. The compression and split tensile behavior of sea shell aggregate mixed concrete comparatively with plain sand concrete was studied under different curing periods such as 7 days, 14 days and 28 days. It was shows that at 20% replacement of crushed sea shell aggregate provide the compressive strength of 35 N/mm2 at 28 days of curing nearly with the design strength of M25 grade conventional concrete. It was also noticed that, the percentage increase of crushed sea shell decline the strength of concrete as radically. Hence it was acclaimed that, the percentage of crushed sea shell as fixed equal or below 10 % to get a better strength of concrete.
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Adakole Okpe, Samuel, and Joseph Ejelikwu Edeh. "Analysis, design and construction of gravity offshore structure; state-of-the-art." International Journal of Advanced Engineering, Sciences and Applications 3, no. 1 (February 1, 2022): 12–17. http://dx.doi.org/10.47346/ijaesa.v3i1.74.
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Abstract: Offshore platforms are divided into many types which are mainly categorized according to waterdepth in the installation location. However, the design differs for each type to accomplish the target of the operation. But for some case of sea waterdepths and an aggressive environment such as the North Sea, steel ones are not suitable, so the heaviest type called gravity platform having enormous mass is used. This type of platform has its special requirements and procedures for construction and needs special types of construction materials in order to resist the climate factors applied due to the aggressive environment. The paper carefully illustrates how the principal Environmental loads (wind and wave), current forces, loads from ice and loads from earth-quake for (earth-quake prone zones) are deployed to archive the design and construction of offshore concrete gravity platforms. Two design methods (Analysis and Design of Shell structures) and the Tangent Modulus Methods of design of Offshore Concrete Gravity platforms are discussed
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Hara, K., M. Awano, H. Tabuchi, and K. Hamada. "Structural Design and Construction of a Long-Span Prestressed Concrete Spherical Shell Roof." Concrete Journal 34, no. 5 (1996): 49–60. http://dx.doi.org/10.3151/coj1975.34.5_49.
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HAMADA, Hideaki, Hirotoshi KOMATSU, and Mutsuro SASAKI. "STRUCTURAL DESIGN AND CONSTRUCTION OF REINFORCED CONCRETE SHELL STRUCTURE WITH SHALLOW FREEFORM SURFACE." AIJ Journal of Technology and Design 23, no. 54 (2017): 453–58. http://dx.doi.org/10.3130/aijt.23.453.
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HAMADA, Hideaki, Hirotoshi KOMATSU, and Mutsuro SASAKI. "STRUCTURAL DESIGN AND CONSTRUCTION OF REINFORCED CONCRETE SHELL STRUCTURE WITH SHALLOW FREEFORM SURFACE." AIJ Journal of Technology and Design 23, no. 55 (2017): 869–74. http://dx.doi.org/10.3130/aijt.23.869.
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Hawkins, Will, John Orr, Paul Shepherd, and Tim Ibell. "Design, Construction and Testing of a Low Carbon Thin-Shell Concrete Flooring System." Structures 18 (April 2019): 60–71. http://dx.doi.org/10.1016/j.istruc.2018.10.006.
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Krivoshapko, Sergey N. "Optimal shells of revolution and main optimizations." Structural Mechanics of Engineering Constructions and Buildings 15, no. 3 (December 15, 2019): 201–9. http://dx.doi.org/10.22363/1815-5235-2019-15-3-201-209.
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Introduction. Optimization is a criterion, on the ground of which, comparative estimation of possible alternatives and selection of the best decisions is carried out. Cost of a shell, its minimum weight, absence of bending moments and tensile normal stresses, given stress state for acting external load, given bearing capacity when optimal shallowness, maximum external load, minimum weight under limitation on the value of natural frequencies of vibration and maximum displacements, absence of bending moments with taking into account internal pressure, dead weight, and centrifugal forces; maximum of critical force and something else can be criterion of selection of optimal shape of shell of revolution. Methods. The main criteria of optimality for shells of revolution and information sources for the 1970-2019 periods are presented in a paper. It will help to study previous results devoted to using optimizations and to set about further investigation. But there is no single approach to the definition of optimal shell of revolution and obviously will not be, because own optimizations are necessary for every concrete case of loading, or distribution of stresses along the thickness, or under the demands to the ratio of the volume and area of considered shell, or with due regard for different kind of expenses, and other demands. Results. For the first time, 24 criteria of optimality only for shells of revolution were discovered. The names of scientists offered presented criteria of optimality and the 45 references dealing with this question are pointed out. It is shown that principles put in the basis of optimal design and criteria of optimality must be given with the help of language quite naturally for computer. Having used optimi- For citation Krivoshapko S.N. (2019). Optimal shells of revolution and main optimizations. Structural Mechanics of Engineering Constructions and Buildings, 15 (3), 201-209. http://dx.doi.org/ 10.22363/1815-5235-2019-15-3-201-209 zations presented in the paper, designers can choose the criterion for their own design of optimal shell shape. Study of the prerequisites of the structural solutions in building and machine-building, the history of the development and perfecting of technologies of erection of shells of revolution will permit to generalize the experience accumulated by designers and to develop new fundamental solutions. Otherwise, architects, structural engineers, and designers will be repeating the achieved solutions in building, architecture, and machine-building.
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Rahman, Muhammad Ekhlasur, Timothy Zhi Hong Ting, Hieng Ho Lau, Brabha Nagaratnam, and Keerthan Poologanathan. "Behaviour of Lightweight Concrete Wall Panel under Axial Loading: Experimental and Numerical Investigation toward Sustainability in Construction Industry." Buildings 11, no. 12 (December 6, 2021): 620. http://dx.doi.org/10.3390/buildings11120620.
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Awareness of sustainability in construction has led to the utilization of waste material such as oil palm shell (OPS) in concrete production. The feasibility of OPS as alternative aggregates in concrete has been widely studied at the material level. Meanwhile, nonlinear concrete material properties are not taken into account in the conventional concrete wall design equations, resulting in underestimation of lightweight concrete’s wall axial capacity. Against these sustainability and technical contexts, this research investigated the buckling behavior of OPS-based lightweight self-compacting concrete (LWSCC) wall. Failure mode, load-deflection responses, and ultimate strength were assessed experimentally. Numerical models have been developed and validated against experimental results. Parametric studies were conducted to study the influence of parameters like slenderness ratio, eccentricity, compressive strength, and elastic modulus. The results showed that the axial strength of concrete wall was very much dependent on these parameters. A generalized semi-empirical design equation, based on equivalent concrete stress block and modified by mathematical regression, has been proposed. The ratio of average calculated results to test results of the proposed equation, when compared to ACI 318, AS 3600, and Eurocode 2 equations, are respectively improved from 0.36, 0.31, and 0.42 to 0.97. This research demonstrates that OPS-based LWSCC concrete can be used for structural axial components and that the equation developed can serve a good guideline for its design, which could encourage automation and promote sustainability in the construction industry.
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Yu, Xian Lin, Jian Shu Ye, and Wen Qing Wu. "Spatial Stress Analysis of Long Span Prestressed Concrete Box Girder Bridges." Applied Mechanics and Materials 256-259 (December 2012): 1693–96. http://dx.doi.org/10.4028/www.scientific.net/amm.256-259.1693.
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A FEA program using 8 nodes and 40 freedoms degenerated solid shell element was developed to analyze the spatial stress of long span prestressed concrete box girder bridges during construction stage and finished stage. The maximum principal tensile stress positions on box girder section and shear lag coefficient were researched according to spatial stress results. It presented suggestions on prestressed concrete box girder bridges anti-crack design.
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Xu, Yu Feng. "Entity Finite Element Simulation of Steel-Concrete Composite Cable-Stayed Bridge." Applied Mechanics and Materials 44-47 (December 2010): 3077–85. http://dx.doi.org/10.4028/www.scientific.net/amm.44-47.3077.
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The finite element simulation is an engineering technology developed with the development of computer technologies, which is also an important development direction of structure design and analysis in the future. With the rapid development of computer software and hardware technologies, it is a tendency to perform the exquisite FE simulation analysis for structure by high performance computer (HPC). In this paper the exquisite FE simulation analysis of global model consisted of block elements and shell elements is performed by means of HPC based on Steel-concrete composite cable-stayed bridge. Moreover, the shrinkage and creep effect in the construction and post-construction period are considered. Besides effectively guiding the design, the high accurate analysis results indicate that it is practical to perform the refined FE simulation analysis by HPC.
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Schultz, Joshua A., and Viktoria Henriksson. "Structural assessment of St. Charles hyperbolic paraboloid roof." Curved and Layered Structures 8, no. 1 (January 1, 2021): 157–66. http://dx.doi.org/10.1515/cls-2021-0015.
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Abstract At the time of completion in 1961, the roof of St. Charles Church became the largest unbalanced hyperbolic paraboloid structure in the United States and the only shell structure in Spokane, WA. Situated on an 8-acre site on the north side of the city, St. Charles is a modernist structure designed through partnership of Funk, Molander & Johnson engineers, architect William C. James and in consultation with Professor T.Y. Lin of the Structural Engineering Laboratory at the University of California, Berkeley. This asymmetric structure spans over 33.5 m (110 ft) and utilizes folded edge beams that taper from 1067 mm (42 in) at the base to a 76.2 mm (3 in) thickness at the topmost edge using regular strength reinforcing steel and concrete load carrying components. The novelty of the pre-stressed shell structure serves both architectural and structural design criteria by delivering a large, uninterrupted interior sanctuary space in materially and economically efficient manner. This structural assessment summarizes the roof’s historic design and construction according to the original construction documents, newspaper reports and historic photographs. The FEA is completed using UBC 1955 design loads and ACI 334 Concrete Shell Structures provisions.
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Mousavian, Elham, and Claudia Casapulla. "Joint Layout Design: Finding the Strongest Connections within Segmental Masonry Arched Forms." Infrastructures 7, no. 1 (January 9, 2022): 9. http://dx.doi.org/10.3390/infrastructures7010009.
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Segmental arched forms composed of discrete units are among the most common construction systems, ranging from historic masonry vaults to contemporary precast concrete shells. Simple fabrication, transport, and assembly have particularly made these structural systems convenient choices to construct infrastructures such as bridges in challenging environmental conditions. The most important drawback of segmental vaults is basically the poor mechanical behaviour at the joints connecting their constituent segments. The influence of the joint shape and location on structural performances has been widely explored in the literature, including studies on different stereotomy, bond patterns, and interlocking joint shapes. To date, however, a few methods have been developed to design optimal joint layouts, but they are limited to extremely limited geometric parameters and material properties. To remedy this, this paper presents a novel method to design the strongest joint layout in 2D arched structures while allowing joints to take on a range of diverse shapes. To do so, a masonry arched form is represented as a layout of potential joints, and the optimization problems developed based on the two plastic methods of classic limit analysis and discontinuity layout optimization find the joint layout that corresponds to the maximum load-bearing capacity.
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Borg Costanzi, C., Z. Y. Ahmed, H. R. Schipper, F. P. Bos, U. Knaack, and R. J. M. Wolfs. "3D Printing Concrete on temporary surfaces: The design and fabrication of a concrete shell structure." Automation in Construction 94 (October 2018): 395–404. http://dx.doi.org/10.1016/j.autcon.2018.06.013.
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Huang, Dongzhou, and Mohsen Shahawy. "Analysis of Tensile Stresses in Transfer Zone of Prestressed Concrete U-Beams." Transportation Research Record: Journal of the Transportation Research Board 1928, no. 1 (January 2005): 134–41. http://dx.doi.org/10.1177/0361198105192800115.
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Prestressed U-beam bridges compare favorably in cost and appearance to traditional concrete I-beam bridges. Consequently, U-beam bridges are gaining in popularity and usage, especially when aesthetic issues are deemed important. U-beam bridges first appeared in Florida in 2000; however, during construction, cracks developed in the webs of the U-beams. This paper presents results of an analysis of representative cracking of U-beams and proposes a practical method for the transfer zone stirrup design. For the purpose of the analysis, the U-beam is divided into a series of finite shell-plate elements, and the prestressing tendons are simulated as a number of concentrated forces. Two different mechanical models of the U-beams are developed on the basis of the stages of construction. Analytical results show that high tensile stresses occur in the end zone of the U-beam because of the prestressing tendons and that these tensile stress must be properly considered in bridge design. The research results are applicable to the design of prestressed U-beams and similar types of prestressed girders.
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Řeháček, Stanislav, Petr Huňka, David Čítek, Jiří Kolísko, and Ivo Šimúnek. "Impact Resistance of Thin-Walled Shell Structures." Applied Mechanics and Materials 617 (August 2014): 96–99. http://dx.doi.org/10.4028/www.scientific.net/amm.617.96.
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Fibre-reinforced composite materials are becoming important in many areas of technological application. In addition to the static load, such structures may be stressed with short-term dynamic loads or even dynamic impact loads during their lifespan. Dynamic effects can be significant especially for thin-walled shell structures and barrier constructions. Impact loading of construction components produces a complex process, where both the characteristics of the design itself and the material parameters influence the resultant behavior. It is clear that reinforced concrete with fibers has a positive impact on increasing the resistance to impact loads. Results of impact load tests carried out on drop-weight test machine are presented in this paper. The results are supplemented by compression strength test.
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Inozemtcev, Sergei Sergeevich, and Evgenij Valerjevich Korolev. "Mineral Carriers for Nanoscale Additives in Bituminous Concrete." Advanced Materials Research 1040 (September 2014): 80–85. http://dx.doi.org/10.4028/www.scientific.net/amr.1040.80.
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To prolong the lifetime and to improve the quality of pavements made of bituminous concretes it is necessary to apply innovative solutions during design of such building materials. The common way to increase the values of operational properties is to admix various modifying additives during production. Nanoscale additives currently constitute the big group of advanced modifiers. The known difficulty limiting the widespread practical use of nanotechnology is the necessity to ensure uniform distribution of nanoscale objects in the volume of material. Thus, to realize nanotechnology in construction it is necessary to use the various carriers for nanoscale modifiers. Several mineral materials (dolomite- and silica-based) were examined and results are presented in this paper. The optimal grain size is determined and optimal modes of grinding were identified to provide conformity of structural parameters for carriers. It is shown that total surface area of diatomite obtained by means of nitrogen absorption method is quite high due to structure of its pore space. It is stated that for structure with numerous contacts between grains, rheological properties of mixture are mostly determined by the thickness and properties of solvation shells on the grains. High surface activity of diatomite is confirmed by the rheology data. It is shown that there is the formation of adsorption layer during interaction between bitumen and surface of diatomite, and thickness of this layer is relatively high for the wide range of temperatures. It is found by means of IR spectroscopy that there is only physical sorption of bitumen on the diatomite and no new chemical compounds are forming.
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Tombesi, P., P. Stracchi, and L. Cardellicchio. "Structural shop drawings at the Sydney Opera House: An instructive model of information flow?" IOP Conference Series: Earth and Environmental Science 1101, no. 9 (November 1, 2022): 092018. http://dx.doi.org/10.1088/1755-1315/1101/9/092018.
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Abstract The history of the design decisions directly related to the construction of the Sydney Opera House remains largely anecdotal. A rich group of items recently discovered in Australia may now start filling this gap, as documents brought to light include the drawings issued by the general contractor to build the concrete formwork for the shells, drawings of the temporary structures and falsework, site images, and contractor’s notes. All in all, the drawings display sophisticated combinatory solutions for attaining the structural form required whilst introducing repetition and flexibility in the making of the discrete pieces. While suggesting a remarkable combination of manufacturing and structural shrewdness, these blueprints call into question the canonical history of the building roof’s famous ‘sails’, the rhetoric of the ‘spherical solution’ used to arrive at them, and, most importantly, the information production and knowledge management model we conventionally work within.
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Perminov, Nikolay A. "The geotechnical modeling of interaction between a large-sized lowered structure and heterogeneous soil environment in the process of embedment." Vestnik MGSU, no. 2 (February 2022): 188–204. http://dx.doi.org/10.22227/1997-0935.2022.2.188-204.
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Introduction. The use of extremely deep and large underground spaces in case of complex geoengineering and hydrogeological conditions is a challenging geotechnical task. The accumulated experience of using the embedment method, that entails the construction of a geotechnical and hydrotechnical enclosure, which is at the same time a reliable bearing structure, has proven a strong technical and economic potential and good prospects for expanding the scope of its application. The study of interaction between large-sized reinforced concrete shells at the stages of their construction in heterogeneous soil environments allowed expanding the scope of their rational use in the subterranean construction that deals with transport and engineering infrastructure facilities. The defect-free construction of a subterranean structure of this type requires a consolidated solution for complex nonlinear design and geotechnical problems.
Materials and methods. The non-stationarity of processes of interaction between a massive structure and the soil environment, as well as the heterogeneity of the environment itself necessitate the development of methods of adaptive control over the stress-strain state of the system that encompasses “a large gravitational body and the heterogeneous environment”. The consolidated geotechnical and structural analysis allows simulating processes of interaction between the shell and the soil environment and prognosticating the parameters of adaptive control over the stress-strain state of the system.
Results. The application of adaptive stress-strain control methods lays the groundwork for a defect-free lifecycle of a structure at the stages of its construction and operation in problematic soils under man-induced impacts.
Conclusions. Unlike the traditional approach, the method, proposed by the author, encompasses the fundamentals of a new concept for assessing the interaction between large-sized structures, embedded in variable strength soils, taking into account the irregularity of the embedment mode and results of its practical implementation focused on the geotechnical support of a defect-free life cycle of unique large-sized subterranean structures at the construction stage.
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Ivanov, G. P., A. G. Trushchov, Y. D. Makarov, and N. G. Ivanova. "Development of Structural Forms for Bulk Material Storage." International Journal of Space Structures 13, no. 2 (June 1998): 83–86. http://dx.doi.org/10.1177/026635119801300204.
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The paper presents research results for improving the shape of civil engineering structures that will be used to store bulk materials. It gives detailed discussion of new structural forms of bunkers and silos which result in more strength and better unloading of bulk materials. The paper demonstrates the advantages of designing the engineering structures as a system of plates and shells. The descriptions of the proposed structural designs are demonstrated with figures. The paper provides the experimental results for large reinforced concrete bunkers of pyramidal/prismatic form.