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Design and construction of concrete formwork
Abstract
Forms are extremely important in concrete construction. They mold the concrete to the required size and shape while controlling its position and alignment (Figure 7.1). Forms are self-supporting structures that are also sufficient to hold the dead load of the reinforcement and fresh concrete and the live load of equipment, workers, and miscellaneous materials (Figure 7.2). In building and designing formwork, three major objectives must be considered: 1. Quality-Forms must be designed and built with sufficient stiffness and accuracy so the size, shape, position, and finish of the cast concrete are attained within the required tolerances.
... The technological development of reinforced concrete 1 has been one great enabler of modern architecture. It is still one of concrete structures [6] and represents a significant source of waste, given that all formwork is discarded sooner or later, contributing to a generally increasing production of waste worldwide. 3 By integrating digital technologies and new insights from material science, well-established casting techniques could be modified to create formwork-efficient and waste reducing approaches for the construction of complex concrete structures. ...
... Further details can be found in [7]. 4 Examples for typical static forms in construction are: slab cast, jump-form, wall forms or column forms. Depending on the application, these forms can be constructed out of steel, wood or plastics, further description can be found in [6]. ...
... The invention is further described in the article [11]. 6 The system of PERI is applied for the construction of silos, water tanks, pipes or recently for buildings such as ADAC Headquarters in Munich, by Sauerbruch and Hutton, a building consisting of a curved 5-storey plinth with an 18-storey curved tower [16,15]. For the construction and planning of such geometries PERI has developed a software tool for architects and planners, which allows to optimize a structure according to a feasible formwork division, hence a software which has the potential of influencing both the design and construction process in the early design phase. ...
... Another important requirement for formwork is to provide proper execution according to the design static model and standards such as (PN-90/M-47850:1990), (PN-EN 13670:2011), (PN-EN 1065:2001, (PN-M-47900-2:1996), (PN-M-47900-3:1996). The main functions which building formwork should perform include (Piekarczyk et al., 2010;Johnston, 2008): to provide the safety of the structure during implementation and use, all of the load capacity conditions should have the appropriate safety factors; to ensure appropriate technical quality such as proper stiffness, placement and geometry of the formwork structure; to be economic in order to minimise the time and costs associated with the implementation, which is related to the effective execution of formwork. The latter factor is especially important because the cost of the formwork (assembly, disassembly, the labour input of the workers etc.) ranges from 35% to 60% of the total cost of construction of concrete structures (Johnston, 2008). ...
... The main functions which building formwork should perform include (Piekarczyk et al., 2010;Johnston, 2008): to provide the safety of the structure during implementation and use, all of the load capacity conditions should have the appropriate safety factors; to ensure appropriate technical quality such as proper stiffness, placement and geometry of the formwork structure; to be economic in order to minimise the time and costs associated with the implementation, which is related to the effective execution of formwork. The latter factor is especially important because the cost of the formwork (assembly, disassembly, the labour input of the workers etc.) ranges from 35% to 60% of the total cost of construction of concrete structures (Johnston, 2008). It is also associated with the kind of structural material from which the formwork is made since it is advisable to use materials with high strength and resistance, including high resistance to corrosion (Brózda and Selejdak, 2018;Lipinski, 2017;Radek et al., 2017). ...
... The use of temporary formwork for concrete construction has a significant impact on construction speed, cost and wastage [1,2]. The cost of formwork is estimated to be about 35%-60% of the overall cost of concrete construction [1]. ...
... The use of temporary formwork for concrete construction has a significant impact on construction speed, cost and wastage [1,2]. The cost of formwork is estimated to be about 35%-60% of the overall cost of concrete construction [1]. Formwork is a major source of wastage in construction as it is often made of timber that is eventually discarded. ...
The extrusion-based concrete printing technology allows the fabrication of permanent formwork with intricate shapes, into which fresh concrete is cast to build structural members with complex geometry. This significantly enhances the geometric freedom of concrete structures without the use of expensive temporary formwork. In addition, with proper material choice for the permanent formwork, the load-bearing capacity and durability of the resulting structure can be improved. This paper investigates the concrete printing of permanent formwork for reinforced concrete (RC) beam construction. A 3D-printable engineered geopolymer composite or strain-hardening geopolymer composite (3DP-EGC or 3DP-SHGC), recently developed by the authors, was used to fabricate the permanent formwork. The 3DP-EGC exhibits strain-hardening behavior under direct tension. Two different printing patterns were used for the soffit of the permanent formwork to investigate the effect of this parameter on the flexural performance of RC beams. A conventionally mold-cast RC beam was also prepared as the control beam for comparison purposes. The results showed that the RC beams constructed using the 3DP-EGC permanent formwork exhibited superior flexural performance to the control beam. Such beams yielded significantly higher cracking load (up to 43%), deflection at ultimate load (up to 60%), ductility index (50%), and absorbed energy (up to 107%) than those of the control beam. The ultimate load was comparable with or slightly higher than that of the control beam. Furthermore, the printing pattern at the soffit of the permanent formwork was found to significantly influence the flexural performance of the RC beams.
... Another important requirement for formwork is to provide proper execution according to the design static model and standards such as (PN-90/M-47850:1990), (PN-EN 13670:2011), (PN-EN 1065:2001, (PN-M-47900-2:1996), (PN-M-47900-3:1996). The main functions which building formwork should perform include (Piekarczyk et al., 2010;Johnston, 2008): to provide the safety of the structure during implementation and use, all of the load capacity conditions should have the appropriate safety factors; to ensure appropriate technical quality such as proper stiffness, placement and geometry of the formwork structure; to be economic in order to minimise the time and costs associated with the implementation, which is related to the effective execution of formwork. The latter factor is especially important because the cost of the formwork (assembly, disassembly, the labour input of the workers etc.) ranges from 35% to 60% of the total cost of construction of concrete structures (Johnston, 2008). ...
... The main functions which building formwork should perform include (Piekarczyk et al., 2010;Johnston, 2008): to provide the safety of the structure during implementation and use, all of the load capacity conditions should have the appropriate safety factors; to ensure appropriate technical quality such as proper stiffness, placement and geometry of the formwork structure; to be economic in order to minimise the time and costs associated with the implementation, which is related to the effective execution of formwork. The latter factor is especially important because the cost of the formwork (assembly, disassembly, the labour input of the workers etc.) ranges from 35% to 60% of the total cost of construction of concrete structures (Johnston, 2008). It is also associated with the kind of structural material from which the formwork is made since it is advisable to use materials with high strength and resistance, including high resistance to corrosion (Brózda and Selejdak, 2018;Lipinski, 2017;Radek et al., 2017). ...
Formwork systems are necessarily used in the implementation of the RC (reinforced concrete) structures. Formworks are required regardless of whether a construction is monolithic or prefabricated and used to form the engineering and general structures or structural elements, such as abutments, supports and decks of the bridges, tanks and retaining walls, but also industrial and accommodation facilities etc. Ensuring the OHS (occupational health and safety) during transport, assembly and disassembly of formworks is a necessary condition for the execution of RC works in a safe and economical way. The paper presents the analysis of the safety requirements for formworks. Furthermore, the general requirements for the execution of the formwork structures were discussed. The most common organizational and technological mistakes and cased of neglects related to the operation of the formwork which lead to infringement of the OHS regulations were also identified.
... De plus, elle permettrait une production souple et peu coûteuse en réduisant l'utilisation d'outils et de moules (Khoshnevis, 2004;Welleret al., 2015;Bos et al., 2016). Les moules, en particulier ceux de formes complexes à usage unique (Gosselin et al., 2016), représentent en effet 35 à 60% du coût total des pièces fabriquées (Johnston, 2008 D'après Wolfs (Wolfs, 2015), la relation entre la forme à imprimer, le matériau cimentaire et les forces appliquées sur le produit imprimé n'est pas encore maîtrisée, un changement au niveau du matériau pouvant nécessiter des changements au niveau des paramètres de pilotage de l'imprimante. La Figure adéquats. ...
... L'utilisation de buses circulaires de diamètre compris entre 6 et 20 mm permet d'imprimer des couches d'épaisseur comprise entre 6 et 25mm . Le et al. ont utilisé un procédé d'impression contrôlé numériquement avec une buse de 9 mm (Dmax =2 mm) (Khoshnevis, 2004;Johnston, 2008). ...
Ce travail s’intéresse à la formulation et à la caractérisation de mortiers cimentaires imprimables en 3D. Il a été réalisé dans le cadre du projet MATRICE cofinancé par le fonds Feder et la région Hauts de France. Un cahier des charges pour un matériau cimentaire imprimable est tout d’abord défini sur la base de trois critères : l’extrudabilité, la constructibilité et la conservation des résistances mécaniques sur matériau imprimé. Deux mortiers imprimables sont formulés en utilisant des essais simples à l’échelle du laboratoire. Le premier mortier, à prise lente, est composé d’un liant à base de ciment Portland (OPC). Le second mortier, à prise accélérée, est composé d’un liant mixte (93 % d’OPC et 7 % de ciment sulfoalumineux (CSA)). Des impressions à l’échelle réelle sont ensuite réalisées dans le cadre du projet MATRICE et permettent de valider leur imprimabilité selon l’application de chacun. Le comportement chimique de mélanges de ciment Portland et de ciment sulfoalumineux est ensuite étudié expérimentalement. Les chaleurs d’hydratation mesurées par calorimétrie isotherme augmentent avec le dosage en CSA (de 2 % jusqu’à 10 %) et sont plus élevées que celles des pâtes de ciment contenant 100 % d’OPC et 100 % de CSA. La comparaison des hydrates identifiés dans le mélange à 7 % de CSA à ceux présents dans les deux pâtes de ciment pures montre que la présence de gypse et de chaux provenant du ciment Portland entraîne une hydratation plus rapide de la ye’elimite provenant du CSA et une formation d’ettringite à très court terme. Par contre, la nature des hydrates du ciment Portland n’est pas affectée. Le comportement rhéologique, notamment, la thixotropie, de pâtes constituées de mélanges de ciment Portland et sulfoalumineux (jusqu’à 10 %) est ensuite étudié en fonction de différents paramètres de formulation pendant la première heure. L’augmentation du dosage en CSA (0 % à 10 %) entraîne une augmentation quasi linéaire du coefficient de structuration (Athix) de ces mélanges. Pour les mélanges à 7 % de CSA et 100 % d’OPC, l’influence du rapport E/C et du dosage en superplastifiant sur la thixotropie est ensuite étudiée. L’augmentation du rapport E/C entraîne une diminution quasi linéaire de Athix pour chacune des pâtes de ciment. En revanche, le superplastifiant présente une faible influence comparativement au rapport E/C.
... Beyond this fact, as much the sizes of the spaces in which water fills as small, the freezing degree of water is so low. It is observed that since gel spaces are very small, most of the freezing action occurs in capillary spaces (Arslan, 1995;Johnston, 1997). The effect of temperature degree is caused by increase in compressive strength of ice as the warmth increases. ...
... From these explanations, it is understood that there are two more factors other than the properties of material in the observed damage of concrete from freezing. These are; the ambient temperature to be below zero and the repetition number of the freezing and thawing events (Johnston, 1997). ...
In this study, freezing and thawing effect over four different high performance concrete (HPC) (0P15Z "0% Pumice + 15% Zeolite", 5P10Z, 10P5Z and 15P0Z) which has been waited in three different cure medium (H 2 O, MgSO 4 and NaCI) for two years was examined. For this reason, four type of High Performance Concrete (HPC) was produced to substitute for, instead of cement. The produced concretes was cured in lime saturated water of 23 ± 2°C, 7500 Mg/L MgSO 4 and 5% NaCI solutions for two years. Before starting the freezing and thawing cycle over the concretes, ultrasonic pulse velocity values were obtained by 28 days of compressive strength. The freezing and thawing experiment over the samples taken out of the cure mediums at the end of two years was made regarding fast freezing -thawing in air from ASTM C 666 standard. At the end of 30 freezing and thawing cycle, concrete compressive strength, weight loss, ultrasonic pulse velocity and durability factor over the samples were determined. The results of the experiment proved that there are important differences in, between values due to mineral admixture type and cure medium.
... Formwork components can be generally classified as Vertical Systems (wall and column) and Horizontal Systems [5,6]. ...
Formwork is among the most determinant factors affecting the cost and completion time of construction projects. In this study, the erection practices, challenges, types, quality and cost of formwork on active building construction projects in Bahir Dar were assessed. The study uses, Questionnaires, site observations and oral interviews with project managers, office and site Engineers, construction managers and carpenters were used to organize and analyse data. From assessment, most of the contractors have given less attention to formwork erection and safety issues. Since the principal criteria for formwork selection are cost and traditional formwork erection, it impacts construction safety and reduces the concrete finishing and quality. Formwork erection is left as the task of carpenters and labourers. There is no proper supervision of the quality of formworks that guarantees construction workers' safety so it is vulnerable to physical injuries and affects employee’s health. From the study, timber formwork is the most dominant type of formwork used for the construction of slabs, beams, columns and stairs due to its availability and low cost. Burnt oil is used as a releasing agent in all construction projects that causes undesirable outputs in concrete surfaces.
... Apart from the type of AM techniques as per ASTM standards [9], the primary benefit of AM is its capacity to convert complex shapes from CAD files into physical prototypes [10]. Its usage for concrete printing has reduced the cost by up to 60% based on the removal of formwork [11,12]. Robocasting and binder jetting are the two most adaptable techniques of AM in the field of construction, the former being mainly categorized in terms of material extrusion-based printing techniques [13], where interfacial porosity and low printing accuracy represent some specific drawbacks [14]. ...
Three-dimensional printing allows accurate geometries to be obtained across a wide range of applications and it is now also moving into the architecture and construction industry. In the present work, a unique binary mix composed of ordinary Portland cement (OPC) and quick-setting cement (QSC) was combined with silica sand aggregate in different proportions for a customized binder jetting 3D printing (BJ3DP) process. Specimens were printed using the blended dry powders and deionized water to determine the impact of the processing variables on the properties of the realized specimens. The results show that the properties are influenced by the binary mix proportions and the layer thickness. The investigation found significant improvement in mechanical performance on increasing the proportion of OPC and optimal conditions were identified with proportions of 35 wt% OPC and 5 wt% QSC. Notable enhancements were also observed as the layer thickness was reduced.
... The emergence of digital fabrication technology has further opened up possibilities to accelerate the prefabrication process by using formwork fabricated with 3D printed concrete (3DPC) [1,2]. 3DPC enables the fabrication of complex geometries in less time and eliminates the need for temporary formwork, which can account for up to 35-60% of the total construction cost [3]. Additionally, 3DPC formwork can significantly reduce construction waste compared to conventional timber formwork, which accounts for up to 30% of the total construction waste generated [4]. ...
... Slip-forming refers to the method of pouring concrete in a continuously moving formwork in an extrusionlike process (See Fig. 5). It can be applied vertically or horizontally [36], e.g. for silos, towers, bridges and roadbeds or curbs. The concrete element is a result of the geometry of the formwork and its motion during the forming process. ...
The adoption of digital fabrication with concrete (DFC) has the potential to bring sustainability, productivity, and process innovation to the construction industry. However, DFC adoption towards market-ready construction systems is lagging due to a lack of understanding in matching its technology capabilities with the needs of potential adopters. This paper describes a DFC Evaluation Framework, analyzing current advancements in DFC through a Conceptual Framework Analysis. The framework is focused on the inputs, process parameters and outcomes of a given technology solution independently of the enabling technology type. It can be used to classify and compare DFC technologies along their systemic characteristics, which are both technical and non-technical in nature. The DFC Scoreboard, an interactive tool to match DFC technologies with the needs of prospective adopters, is developed and tested based on the framework. The paper discusses how the DFC Evaluation Framework and Scoreboard offer one of the first systemic overviews of DFC adoption, with the capability to match technology capabilities and user needs in the technology adoption process.
... Reducing or removing formwork costs is an appealing argument to an AEC Industry that is often operating with tight budgets and short timelines. The stated cost of formwork can be traced to a chapter 'Design and Construction of Concrete Formwork' in a handbook published in the US in 2008 (Johnston, 2008). Johnston explains that this cost is usually due to complex on-site formwork construction. ...
This paper aims to identify the current status of research in 3D concrete printing (3DCP), locate the sustainability considerations relevant to these trajectories, and to identify a gap in knowledge and future research challenge regarding the sustainability of 3DCP. To categorize the broad range of research topics within 3DCP, the paper introduces an assessment framework that subdivides this field into three sub-fields: material science, computational design, and structure and performance. Common sustainability considerations are identified for each of these sub-fields. As a result of this analysis, a lack of critical assessments on claims about the sustainability and environmental impacts of 3DCP is identified.
Our survey of literature, and its analysis via this framework, finds that whilst certain sustainability aspects are highlighted, other measures and considerations are skimmed over, or omitted. It is found that whilst material optimization and the ability to create formwork-free, complex forms is noted as a main argument for the implementation of 3DCP, this claim is largely unsupported by reference or reported outcomes, and the environmental impacts are often only briefly discussed. There is a clear need for a holistic view on the sustainability issues which surround 3DCP.
This paper further highlights the lack of comprehensive assessment tools and metrics for measuring the environmental impact of 3DCP and concludes that further research must be done to develop these tools, to allow architects to integrate 3DCP into sustainability-oriented design workflows. Our paper concludes that the development of these tools will lead to a more comprehensive understanding on the environmental sustainability of 3DCP, allowing research resources to be focused within each field to ensure 3DCP continues to develop in a sustainable way.
... Concrete elements require formworks for their manufacture [10], where the cost of formworks can vary between 35% to 60% of the total cost of the concrete structure [23]. Therefore, the possibility that structures can be built without the need of using formworks creates great advantages for the construction industry, reducing costs and manufacturing times [24]. ...
Historically, the construction industry has exhibited slow technological development when compared to other industries. However, during the last several years, investigations related to automation in construction have been conducted, such as additive manufacturing in concrete. This study aims to delve into this topic, providing effective communication between BIM-designed elements and its additive concrete manufacturing, with the help of an articulated robotic arm. Therefore, the paper addresses the preparation of computer code that allows such BIM–robot communication, checking the parameters utilized, and analyzing the results of tests with the equipment involved.
... 7 3DCP presents a threefold sustainability opportunity, from economic, environmental, and social perspectives. 8 This process eliminates the need for any type of formwork, reducing the cost of a concrete structure by 35-60%, 9 and significantly reducing the necessary man labor. The integration of digital design, collaboration, and Building Information Modeling and cost and time reduction of a robotically fabricated concrete have large potential for the increase of productivity. ...
This article presents a review of the current solutions for the rheological challenge of three-dimensional concrete printing (3DCP), providing a rheological definition for printability, and an overview of the current techniques for obtaining a printable concrete, placing special emphasis on understanding structural build-up and the current mixture proportions and admixtures used to improve it. A promising alternative for improving structural build-up is the use of entrained air (EA), as bubbles, whose effects are reviewed in generic yield stress fluids and then specifically in concrete. After revision of micromechanical models and experimental trials from literature on yield stress fluid bubble suspensions and concrete, EA appears to be ideal for 3DCP when generated by anionic surfactants, as it increases static yield stress and decreases plastic viscosity. Cationic surfactants, however, maintain or slightly decrease static yield stress. It is proposed that the lubricating or stiffening property of the bubbles determines their ability to deform under the shear stress generated by the surrounding fluid. The ability to deform depends on the surfactant used to entrain the bubbles and the mixture design of the concrete. Further experimental research must be carried out for the advantages of EA to be fully realized.
... Research shows that by optimizing concrete geometry, it is possible to achieve material savings of up to 70% compared to a standard concrete building component [1]. These types of optimized building components, however, are expensive to fabricate, mainly due to the difficulty of constructing the formwork [2]. This is one of the reasons complex, non-standard concrete structures remain uncommon. ...
This paper describes the design and fabrication process of a concrete column cast in ultra-thin, 3D printed formwork, using a process known as Eggshell. The column was prefabricated as part of a real-world construction project, serving as the main load-bearing element for a reciprocal timber frame structure. The fabrication of the column required upscaling of the Eggshell process, to allow for the fabrication of elements of an architectural scale. Furthermore, several challenges had to be addressed such as: integration of reinforcement, establishing the formwork design space, and scaling up the 3D printing process. For the production of the final column a 1.5 mm thin formwork was 3D printed, after which it was combined with a prefabricated reinforcement cage and filled with concrete in a set-on-demand casting process. The successful realization of the project provides a first example of a full-scale building element produced with the Eggshell fabrication process. By 3D printing the formwork, geometrical freedom in concrete construction is greatly expanded, as well as formwork waste reduced.
... The factor making less attractive the application of double-curved thin concrete shells is that their final cost is very high due to the costs of formworks and scaffolding requiring considerable labor. However, even today, with the standardized formwork systems, the overall cost of formwork represents 30-60% of the total costs for concrete structures [6]. ...
The development of new digital design tools and fabrication technologies stimulated a large research interest in the design and construction of free-form architecture. Free-form architecture indicates the symbolic act of freeing architecture from the limitations of pure form. During the form-finding process, the priority is on identifying the geometry that enables the optimum force flow within the structure.
This study focuses on the problem of the form-finding problem of concrete double-curved surfaces. First, a suitable form-finding optimization framework to optimize shell surfaces based on the surface Stress Density method is established. This framework is based on the use of different software such as Rhinoceros, Grasshopper, and Matlab. The stress density method is chosen because it allows obtaining an optimized shape starting by few parameters: the geometric characteristics of the model, the surface density factor and the magnitude of the load. In a second step, the study is focused on a single panel of the structure. Structural analyses of this panel are carried out using the commercial finite element software SAP2000 to demonstrate that it is a shape resistant structure. Finally, a new production process for concrete double-curved surfaces is presented showing a prototype at a small scale. This process is trying to satisfy the needs of new shapes within architectural design. The proposed solution is the improvement of an existing flexible mould formwork technology and represents the first attempt to reach a reusable, reconfigurable and affordable procedure.
... For instance, at Hong Kong in 2013, approximately 3,591 tonnes of construction waste were disposed of daily, representing 25% of total solid waste received at landfills [5]. Moreover, the fabrication and construction of these formworks, represent 35% -60% of the total concrete work cost [6]. ...
The paper presents new results about the geometry of topological interlocking masonries and some possibilities they present to build without formwork. Construction without the use of formwork may be an important issue concerning both productivity increase and decreasing of waste generated on a construction site. Due to the development of computational design and robotics in the construction industry, it makes sense to (re)explore innovative design and process of complex masonry structures. The design of this kind of masonry is standard for planar structures, and in this paper, a generalisation is proposed for the parametric design of curved structures. To achieve this, a criterion for translationally interlocked structure based on quadrilateral meshes is exhibited. The application of this criterion is then extended to masonry structures derived from other patterns. Physical prototypes of topological interlocking masonry are also presented. One of these designs seems to allow construction without formwork.
... Future studies may develop algorithms and techniques to automate the shape design of steel reinforcement bars with multiple bends and prepare the corresponding drawings for scheduling and optimum quantity take-off. As the formwork represents 35%e60% of the overall cost in the construction of concrete structures (Johnston, 2008), the formwork should also be optimized sufficiently for associative installation of rebars with multiple bents. Due to the millions of elements with different dimensions and sizes are expected in designs of complex RC structures, automation is critically needed to prepare the drawings for each element with extensive level of detailing. ...
Building design optimization plays an important role in maximizing the reliability, cost efficiency, and environmental sustainability of constructed facilities. As the construction of reinforced concrete (RC) structures consumed tremendous amounts of steel reinforcement and concrete, RC structural design optimization for minimal environmental impact has attracted increasing attentions from academics and industry in recent years. Nowadays, new information technologies and computing techniques were increasingly utilized for the sustainable design and optimization of RC structures to maximize energy efficiency, but it still lacks a critical review to summarize the common research themes and highlight the future needs in this field. Therefore, the primary objective of this paper is to critically review the previous research related to the computational design optimization of RC structures for the minimum environmental impact, with the aim of highlighting the present status and future trends for the advancement of building design optimization. First, the general introduction and background for importance of multidisciplinary detailed design optimization of RC structures are described. Thereafter, a critical review of available research objectives, structural components, optimization strategies, and the use of different computational tools in RC structural design optimization to integrate sustainability in constructional design stage, is provided in this paper. Furthermore, different research trends are analyzed and critically discussed in detail. Potential research directions to better quantify and evaluate the implementation of detailed RC structural design optimization are presented. This paper can assist structural design practitioners in academia and industry to introduce new horizons of sustainable construction by considering multiple aspects of detailed RC structural design and combining several computational tools with optimization strategies.
... Another potential benefit from AM is the reduction of formwork (and related temporary structures) used during construction. Concrete structures are commonly built using temporary formwork to maintain the desired shape of fresh concrete as it hardens, and formwork labor and material costs range from 35 to 60% of the overall cost of concrete structures [14,15,16]. The most common formwork is made from wood, using subtractive processes to cut it to the desired shape, producing waste material before it is even used. ...
Additive manufacturing (AM), also known as 3D printing, fabricates components in a layerwise fashion directly from a digital file. Many of the early applications of AM technologies have been in the aerospace, automotive, and healthcare industries. Building on the advances in AM in these industries, there are several experimental applications of AM in the construction sector. Early investigations suggest that use of AM technologies for construction have the potential to decrease labor costs, reduce material waste, and create customized complex geometries that are difficult to achieve using conventional construction techniques. However, these initial investigations do not cover the full range of potential applications for construction or exploit the rapidly maturing AM technologies for a variety of material types. This paper provides an up-to-date review of AM as it relates to the construction industry, identifies the trend of AM processes and materials being used, and discusses related methods of implementing AM and potential advancements in applications of AM. Examples of potential advancements include use of multi-materials (e.g., use of high-performance materials only in areas where they are needed), in-situ repair in locations that are difficult or dangerous for humans to access, disaster relief construction in areas with limited construction workforce and material resources, structural and non-structural elements with optimized topologies, and customized parts of high value. AM's future in the construction industry is promising, but interdisciplinary research is still needed to provide new materials, new processes, faster printing, quality assurance, and data on mechanical properties before AM can realize its full potential in infrastructure construction.
... Aside from its key role in defining the shape of concrete structures, formwork is also a critical topic in concrete construction because it is the source of roughly 50% of the overall costs -more than the costs of cementitious materials, aggregates, additives, reinforcement and labour combined (Johnston, 2008). For one-of-a-kind, non-standard shapes, the costs of formwork can be even more significant. ...
The imperative need for complex geometries in architecture is driving innovation towards an unconstrained fabrication freedom in building components. Fabrication constraints are a critical obstacle when material efficiency through complex, optimized topologies is sought. To address this constraint, this research investigates the use of 3D printed plastic formwork for fibre reinforced concrete at large scale. This novel construction method makes complex topologies and precise details possible for full-scale, load bearing structures. To demonstrate its potential applications, SkelETHon —a functional four-meter-long concrete canoe— was designed, built and raced in a regatta on the Rhine river.
... Another potential benefit from AM, is the reduction of formwork used during construction. Currently, concrete structures are commonly built using temporary formwork to maintain the desired shape of wet concrete as it hardens, and that formwork labour and material ranges from 35-60% of the overall cost of the concrete structures [6]. Reducing formwork use, not only reduces waste material produced during construction, which is considered to be about 23% of the total material wasted in the country [2], but it also reduces construction cost and time that is required for placing and disassembling the formworks. ...
... Regardless of the simplification in construction through the use of straight, elongated elements, the use of material for shuttering and scaffolding is still substantial. Even today, with the standardised formwork systems available, the overall cost of formwork represents 35%-60% of the total costs for concrete structures (Johnston, 2008). ...
Addressing both architects and engineers, this dissertation presents a new framework for the form finding and design of fabrication geometry of discrete, funicular structures in the early design phase. Motivated by ongoing debates about digital architecture and funicular shell form finding, it introduces a new methodology for structurally-informed design of curved surface architecture through the use of geometrical rather than analytical or numerical representations of the relation between form, forces and fabrication. Based on Thrust Network Analysis (TNA), new algorithms are presented that enable an interactive exploration of novel funicular shapes, enriching the known formal vocabulary of shell architecture. Using TNA, the framework adopts the same advantages of techniques like graphic statics, providing an intuitive and educational approach to structural design that ranges from simple explorations to geometry-based optimisation techniques. Complementary to this structurally-informed design process, the work reflects on the latest building technologies while also revisiting historic construction techniques for stereotomic stone masonry and prefabricated concrete shells to develop efficient fabrication design strategies for discrete funicular structures. Based on architectural, structural and fabrication requirements, several tessellation approaches for given thrust surfaces are developed for the design of informed discretisation layouts of any funicular shape. The flexibility and feasibility of the form-finding framework is demonstrated in several case studies employing the new structural design tool RhinoVAULT, which implements the developed form-finding methods. The use of fabrication design strategies is discussed in a comprehensive case study that shows project-specific tessellation design variations and first fabrication results for a complex stone masonry shell.
3D-printed concrete (3DPC) is a layered anisotropic material whose properties are significantly impacted by the production parameters. To design and analyze large-scale printed structures, it is vital to understand the spatial variation of material properties throughout full-scale printed components. Presented study addresses this need by presenting a comprehensive experimental investigation that explores the variation of physical, mechanical, and thermophysical properties across a full-scale 3DPC wall with an approximate height of 2.36 m. The cores extracted from the wall were categorized in terms of the extraction location along the wall height (upper (U) and lower (L)) and the alignment of the specimen’s longitudinal axis with respect to the printing space (printing (P), translation (T), and deposition (D) direction). Additionally, direct shear and four-point bending tests were carried out on printed beams. Control samples, mold-cast from the same concrete mix, were used for comparison. Obtained results indicated a pronounced anisotropy and property variation along the 3DPC wall height. These were linked not only to the frequency and orientation but also to the porosity of the interfaces which was significantly influenced by the self-weight compaction of the layers and the progressively increasing concrete viscosity caused by pump system heating over time. CT investigations, rate of water absorption, and water penetration tests revealed sparse and less connected interstrip and interlayer porosity in the L samples. Depending on the sample orientation and loading direction, compressive strength, elastic modulus and splitting tensile strength increased by up to 108 %, 53 %, and 100 %, respectively, in the L samples when compared to the U samples. The same trend was observed in the Poisson’s ratio, albeit to a lesser extent. The triaxial thermal conductivities of the L samples calculated from the transient plane source measurements were up to 26 % higher than those for the U samples. Given the limited number of studies on real-scale applications, the presented research can serve as a benchmark, offering valuable insights to explore and validate the 3DPC behavior on a large scale.
In enhancing the living standards of the society advanced technologies can be used in gaining the labour productivity and competitive advantage. There the low-cost housing projects are facilitating a proper labour productivity adhering the effect of labour productivity factors. Thereby, Aluminium system formwork is a use of advanced methodology which enhance the labour productivity in low-cost housing projects while highlighting the significance and domain created within the industry.
Meanwhile, tendency of poor performance in Aluminium System Formwork is observed due to improper planning in high rise building construction. Consequently when maintaining productive advantage, productivity norms are number of labour hours required to complete a particular task while facilitating the efficient evaluation of labour performance in enhancing the merits of the Aluminium System Formwork. Hence, deficiency of researches have been done to establish particular standards or norms, this research aims at investigating the realistic measure of the labour performance for Aluminium System Formwork in low cost housing projects.
Accordingly, a case study was conducted using direct observations to prepare the labour productivity norms and collected data were analysed based on labour productivity factors. Finally conclusions were drawn and recommendations were put forward.
Findings proved the combination and varying effect of weather factors, crew factors, management and projects factors, site conditions represent different labour productivity norms in each four different occasions. Meanwhile within each occasion the effect of structural elements towards the norms is highlighted and facilities the realistic measurement of the labour performance in Aluminium system formwork while embossing low cast housing concept.
The subject of this analysis is connected with the verification of the load capacity of the span structure taking into account the degree of corrosion of the railway viaduct components located at 41.446 km, on the railway line no. 301 of "Kotlarnia" SA Sand Mine built over the national road DK88 and railway tracks PKP-PLK near T. Kościuszki street in Zabrze The general condition of the structure with regard to the corrosion assessment of structural steel is presented in the paper. Static and strength calculations were carried out to determine the load capacity class, and as a result of the analysis it was found that the technical condition of the facility steel girders is suitable for repair.
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