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The use of three-dimensional (3D) printed concrete as formwork is becoming more widely applied within the industry. However, the technology is still not optimized and there are many reports of preliminary cracking during the curing of cast concrete. This is believed to result from differential shrinkage between the printed and cast concrete. These cracks (in the printed concrete or at the interface between the infill and printed concrete) form a preferential path for aggressive substances and can reduce the durability of the combined concrete element. To ensure the desired service life of the structure, it is important that the differential shrinkage between cast and printed concrete is understood. This study investigated the effect of curing conditions on the differential shrinkage behavior of 3D and cast concrete. The influence of prewetting of the dry-cured 3D printed formwork was also determined. In the experimental program, a vibrated and self-compacting concrete were used as cast material. Linear 3D printed formwork was produced and combined with cast concrete to simulate a concrete structure. Printed formwork was cured for 1, 7, or 28 d exposed to the air (relative humidity: 60% or 95%) or submerged in water. The length change of the combined elements was observed over 56 d after concrete casting and throughout the thickness of the materials. Results show that increasing the curing period in dry conditions of the printed concrete leads to an expansion of the formwork on the first day after casting. The expansion leads to a non-uniform strain evolution throughout the curing period of the combined element. Printed concrete formwork stored in wet conditions does not expand after the casting process but tends to show a decreasing linear deformation within the whole elements. [ABSTRACT FROM AUTHOR]

Part of the walls of the cast-in-place tunnel in the west artificial island of the Shenzhen -Zhongshan Link are curved structures with gradually changing curvature. In order to adapt to the construction of the tunnel arc-shaped structure, the construction technology of steel-timber composite arc-shaped formwork was studied by combining the preliminary design and field process verification. The engineering practice has proved that this technology can better solve the problem of low generality of curved wall formwork with variable curvature. Compared with conventional custom steel formwork or random wood formwork system, the steel-timber composite arc-shaped formwork system has obvious advantages in quality, safety and cost control, which can provide reference for similar projects. [ABSTRACT FROM AUTHOR]

Self-compacting concrete (SCC) is the most flowable concrete type that exerts high pressure on formwork. SCC is the most commonly used concrete globally for construction applications due to its cost-effectiveness. However, to make a formwork resist the exerted lateral pressure of SCC, it is required to have a suitable design for formwork. This paper presents a novel approach on how could create and prepare the Fiber Bragg Grating (FBG) optics using as a sensor to measure lateral pressure and temperature of SCC. To ensure the FBG sensor works properly a validated methodology is conducted. In the first stage, FBG sensors are calibrated with temperature sensitivity and then are calibrated with water pressure. The latter calibration is used to verify lateral pressure with SCC. However, this is not the only sensor used to record the result, a genuine sensor such as a transducer sensor has been positioned close to the FBG sensor to validate the results of the FBG sensor. The created FBG sensor demonstrates highly promising results, effectively validating the outcomes of the transducer sensor, while also reducing costs and enhancing usability for construction applications. [ABSTRACT FROM AUTHOR]

Building the structural components is crucial for constructing a multi-story building. In the process of creating these components, which is commonly done through casting, a tool called formwork is required. Formwork is a tool used to mold the necessary concrete structures, ensuring that their shape and dimensions align with the concrete material's planning. Formwork tasks for concrete work significantly impact costs. Different formwork options, including traditional, semi-system, and full-system forms, are available. This research aims to assess cost-effectiveness through value engineering, specifically focusing on column formwork, by comparing their utilization in a multi-story construction project. The study begins by collecting primary data, namely working drawings, so that the volume of conventional formwork can be calculated. Then, budget planning calculations are made to analyze the cost comparison of each formwork alternative. The selection of the appropriate formwork affects the speed of execution and the costs incurredIn this construction project for the building, the conventional column formwork results in expenses amounting to IDR 587,749,263.04 and requires 28 days for completion, while semi-system column formwork achieves a 37% cost saving with the same duration of 28 days, and full-system column formwork becomes 64% more cost-effective with a construction period of 10 days.

In this paper, the concept of steel fiber reinforced concrete (SFRC)‐plastic columns was explored and discussed. Plastic served as a 3D printed formwork that remained in place. Five different column cross‐section shapes, based on Cesaro fractal iterations, were created and filled with steel fiber reinforced mortar. After curing, the specimens were loaded and load‐strain characteristics were recorded, with a focus on destruction characteristics and energy dissipated up to 6.0% strain. The results showed that columns with fractal‐based cross‐sections had smooth destruction with significant formwork deformation. All columns exhibited highly quasi‐plastic behavior. The results demonstrate the feasibility of replacing traditional formwork and concrete with a more automated 3D printed plastic and SFRC solution. Future research should focus on large‐scale columns and other structural elements. [ABSTRACT FROM AUTHOR]

Formwork and trolley structures are commonly used in engineering construction projects, but are rarely used in cast-in-place connection sections of immersed tunnels. Based on the example of the Dalian Bay Subsea Tunnel Project, this paper introduces the application of formwork and trolley structures in the template system of the connection section of the immersed tunnel, including the design form of the formwork and trolley structures, the construction process and methods of each layer cast-in-place of the connection section's bottom plate, middle wall, and top plate, summarizes the application effect of form work and trolley structures, and put forward improvement suggestions. The smooth application of formwork and trolley can provide reference for the construction of box culvert structures such as connection sections and pipe galleries of layered cast in-place immersed tunnels. [ABSTRACT FROM AUTHOR]

For this special issue, sustainability and safety are discussed through the tropes of both material and work process substitution. As an architecture and industrial design team, we examine the potential of William McDonough's and Michael Braungart's "cradle to cradle" material methodology, and David Pye's "the workmanship of certainty" as relevant to the construction industry. Locating and revisiting the tenets of Gottfried Semper's Stoffwechseltheorie, alongside contemporary critiques, demonstrates that if historically, material and technique substitution led to architectural innovation, the same conditions exist today. To demonstrate a contemporary Stoffwechsel (material substitution) a formwork prototype was constructed at the University of Canberra's Workshop 7, by substituting timber with plastic, and 3D-printing the formwork. This prototype demonstrates a type of "technical nutrient" that is both recyclable as plastic, and reusable as formwork. This reveals the potential of substituting materials and processes not only to achieve material recovery, but rather, aiming for material recycling, reuse, or upcycling, therefore reducing socio-environmental risks in construction. [ABSTRACT FROM AUTHOR]

Forecasting the maximum pressure exerted by cast-in-place self-compacting concrete (SCC) is a major concern for formwork designers, researchers, and site engineers to accurately design the bearing capacity of the formwork and control the casting rate for safe and fast construction. This article aims to utilize the ARX-Laguerre model, which is a data-driven model to forecast the maximum form pressure. A laboratory instrumented setup was used to cast a 2-m column using SCC made with two different types of cement. A pressure system consisting of four sensors was used to document the pressure during casting. The data were sent to the cloud at every 1-min interval for real-time monitoring. The data were used to develop the model. The results demonstrated that forecasting with the ARX-Laguerre model is highly accurate. The model can forecast the maximum pressure exerted by SCC with less complexity. The model performance was also found to be consistent with insignificant differences between actual experimental results and predicted results. With a recursive and straightforward representation, the resulting model, known as the ARX-Laguerre model, ensures the parameter number reduction. Providing fast prediction of the maximum pressure. The model enables formwork designers to forecast the form pressure to design safe formwork and also helps to control the casting rate when SCC is used.

Copyright of VAD: Veredes, Arquitectura y Divulgación is the property of Alberto Alonso Oro and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

For this special issue, sustainability and safety are discussed through the tropes of both material and work process substitution. As an architecture and industrial design team, we examine the potential of William McDonough’s and Michael Braungart’s “cradle to cradle” material methodology, and David Pye’s “the workmanship of certainty” as relevant to the construction industry. Locating and revisiting the tenets of Gottfried Semper’s Stoffwechseltheorie, alongside contemporary critiques, demonstrates that if historically, material and technique substitution led to architectural innovation, the same conditions exist today. To demonstrate a contemporary Stoffwechsel (material substitution) a formwork prototype was constructed at the University of Canberra’s Workshop 7, by substituting timber with plastic, and 3D-printing the formwork. This prototype demonstrates a type of “technical nutrient” that is both recyclable as plastic, and reusable as formwork. This reveals the potential of substituting materials and processes not only to achieve material recovery, but rather, aiming for material recycling, reuse, or upcycling, therefore reducing socio-environmental risks in construction.

The Semarang-Demak Toll Road was planned with detailed procedures to address disorganized road networks, increased traffic volumes, congestion, land subsidence, and tidal floods. It has toll entrances in Semarang, Genuk, and Sayung sub-districts and ends in Demak City. Its purpose is to minimize traffic jams, provide access to tourist cities, and serve as a tidal barrier sea embankment. The formwork support system's proper design is crucial to ensure the safe construction of the main structure. A unique disk lock and steel tubular scaffold are utilized for a slab-on-pile structure employing a flying falsework system. This approach results in a structurally sound and secure construction that is not susceptible to twisting, providing quick erection and disassembly, significantly improving construction efficiency. The system was employed in a portion of the Semarang-Demak toll road project, and its efficacy was evaluated using finite element analysis software. The software provides security and convenience in analyzing structures, paying attention to the nominal strength of each steel profile and the internal forces at work. All components are safe as their actual deflection falls within the maximum limit.

Contractors are interested in removing and reusing the formwork from concrete walls as soon as possible to speed up construction. While the concrete may have sufficient strength, there is little information about the impact on the durability of the concrete if the forms are removed at early ages. Curing is known to maintain the concrete moisture and promote hydration to create a denser microstructure. This research investigates the type of forms, formwork removal timing, and the impact of subsequent curing methods on the drying rate and ion penetration of concrete. This study shows that early form removal does impact the durability of the concrete and subsequent usage of curing compounds or plastic can extend the curing and improve the durability of the concrete. This work quantifies the differences and provides practical recommendations for the concrete industry. [ABSTRACT FROM AUTHOR]

The cost of producing one cubic meter of concrete structure, depending on the structure's shape, type, and complexity, can be variously high. The cost of concrete, reinforcement, formwork, and labor ratio varies. But unlike the cost of concrete and reinforcement, which tend to be similar in the terms of the conditions of a particular construction project, the cost of formwork and work with it are different for different contractors. It often depends on the appropriateness of the formwork system used, the optimal placement of the formwork sets, the minimization of downtime, and the efficiency of the carpenters' work. Formwork modeling in the construction preparation phase intervenes in this planning area, where construction sources are defined and quantified, and the time course of their deployment is determined. The current paper deals with optimizing formwork selection and deployment in concrete structure execution. Even if several requirements must be considered when selecting and modeling the formwork (e.g., construction time, quality of concrete structure, etc.), an effort to minimize the cost of formwork, and thus construction cost, plays the most significant role. A dynamic model for effective and optimal planning of formwork in construction projects, including formwork cost analysis, is presented in the paper. The included case study demonstrated the planning of the formwork through a software application developed based on the computational algorithm of the dynamic model presented. A case study is presented in the article as a research method. An office building with five above-ground floors and one underground floor was chosen for the case study. To solve the case study, the formwork for horizontal structures (i.e., beams and slabs) is considered. The goal of the case study is to identify research questions and apply time and cost optimization to a selected specific building. [ABSTRACT FROM AUTHOR]

The clean water intake building was built along with a service bridge that functions as accessibility. This bridge is made using reinforced concrete structures and piles. The concrete casting uses traditional formwork with wood materials. This study aims to determine the strength of the formwork and the sequence of installation. The stages of the study include field data observation, drawing into technical structural drawings, strength analysis, and drawing conclusions. The results obtained are in the form of a formwork structure load flow scheme that works on construction. Then obtained the cross-sectional capacity of the retaining beam (galam wood) which is can withstand the bending moment, shear force, and deflection of the casting load. Likewise, the girders (ironwood) and steel hangers withstand the construction load on them. In addition, the size of the ironwood used can be reduced to a smaller size of 8x8 cm, resulting in savings in implementation costs. [ABSTRACT FROM AUTHOR]

Despite the advantageous benefits offered by self-compacting concrete, its uses are still limited due to the high pressure exerted on the formwork. Different parameters, such as those related to concrete mix design, the properties of newly poured concrete, and placement method, have an impact on form pressure. The question remains unanswered on the degree of the impact for each parameter. Therefore, this study aims to study the level of impact of these parameters, including slump flow, T500 time, fresh concrete density, air content, static yield stress, concrete setting time, and concrete temperature. To mimic the casting scenario, 2 m columns were cast at various casting rates and a laboratory setup was developed. A pressure system that can wirelessly and continuously record pressure was used to monitor the pressure. Each parameter's impact on the level of pressure was examined separately. Casting rate and slump flow were shown to have a greater influence on pressure. The results also demonstrated that, while higher thixotropy causes form pressure to rapidly decrease, a high casting rate and high slump flow lead to high pressure. This study suggests that more thorough analysis should be conducted of additional factors that may have an impact, such as the placement method, which was not included in this publication. [ABSTRACT FROM AUTHOR]

The utilization of ultra-high-performance concrete (UHPC) permanent formwork could facilitate the construction of hydraulic concrete structures. However, the joints between UHPC formwork are the vulnerable parts of a whole permanent formwork system. This study aimed to develop a High Strength Cementitious Grout (HSCG) for filling these joints, integrating the formwork system, and minimizing the adverse influence on these joints. The aggregate size for the HSCG was optimized, and four kinds of admixtures (i.e., hydrophobic powder (HP), expansive agent (EA), redispersible polymer powder (RPP), and cellulose ether (CE)) and PVA fibers were used to improve the HSCG. The HSCG with different aggregate sizes, admixture dosages, and PVA fiber contents were experimentally investigated. By evaluating the compressive, tensile, flexural, and adhesive strengths of the prepared grout, the aggregate size range was recommended to be 0.15–0.30 ​mm, while the suggested contents of HP, EA, RPP, and CE were 0%, 6%, 2%, and 0.1%, respectively, by weight of binding materials. In addition, the optimal volume content of PVA fibers was 0.45%. In order to avoid the introduced foams, 0.2% of the defoamers were used in combination with the CE. After that, six combinations were tested to consider the coupled effect of different admixtures and PVA fibers on the HSCG. In consideration of the strengths, shrinkage, and abrasion resistance to water impact, the HSCG with the combination of (EA ​+ ​RPP ​+ ​CE), the aggregate size of 0.15–0.30 ​mm showed the optimal overall performance and was regarded as the most suitable HSCG for grouting.

In this study, a modified Artificial Neural Network (ANN) and Support Vector Regression (SVR) with three different optimization algorithms (Genetic, Salp Swarm and Grasshopper) were used to establish an accurate and easy-to-use module to predict the lateral pressure exerted by fresh concrete on formwork based on three main inputs, namely mix proportions (cement content, w/c, coarse aggregates, fine aggregates and admixture agent), casting rate, and height of specimens. The data have been obtained from 30 previously piloted experimental studies (resulted 113 samples). Achieved results for the model including all the input data provide the most excellent prediction of the exerted lateral pressure. Additionally, having different magnitudes of powder volume, aggregate volume and fluid content in the mix exposes different rising and descending in the lateral pressure outcomes. The results indicate that each model has its own advantages and disadvantages; however, the root mean square error values of the SVR models are lower than that of the ANN model. Additionally, the proposed models have been validated and all of them can accurately predict the lateral pressure of fresh concrete on the panel of the formwork. [ABSTRACT FROM AUTHOR]

Even though computational design has paved the way for the design of complex forms, construction is still difficult, inefficient, and costly. This paper aims to compile the most recent fabrication techniques for shell structures to create an overview of fabrication methods. This paper reviews existing, recently developed, and previously unexplored techniques for building and fabricating shell structures. The objective of this review is to find trends, patterns, or gaps in the literature that can direct future research. As a result, each fabrication technique is explained and demonstrated with relevant built projects. Moreover, each method's advantages, disadvantages, and limitations are highlighted. These techniques are grouped into four main classes and evaluated. In conclusion, categorizing fabrication techniques reveals the state-of-the-art in fabrication and highlights potential research gaps. Moreover, this research might encourage researchers to explore novel methods and solutions to overcome the current method's limitations. • The state-of-the-art fabrication techniques for shell structures are presented. • A comprehensive, up-to-date literature review of fabrication methods is presented. • The methods of fabrication are classified in an exclusive manner. • The pros and cons of fabrication techniques are discussed. • This review highlights the current gaps in fabrication methods. [ABSTRACT FROM AUTHOR]

The cost of producing one cubic meter of concrete structure, depending on the structure’s shape, type, and complexity, can be variously high. The cost of concrete, reinforcement, formwork, and labor ratio varies. But unlike the cost of concrete and reinforcement, which tend to be similar in the terms of the conditions of a particular construction project, the cost of formwork and work with it are different for different contractors. It often depends on the appropriateness of the formwork system used, the optimal placement of the formwork sets, the minimization of downtime, and the efficiency of the carpenters’ work. Formwork modeling in the construction preparation phase intervenes in this planning area, where construction sources are defined and quantified, and the time course of their deployment is determined. The current paper deals with optimizing formwork selection and deployment in concrete structure execution. Even if several requirements must be considered when selecting and modeling the formwork (e.g., construction time, quality of concrete structure, etc.), an effort to minimize the cost of formwork, and thus construction cost, plays the most significant role. A dynamic model for effective and optimal planning of formwork in construction projects, including formwork cost analysis, is presented in the paper. The included case study demonstrated the planning of the formwork through a software application developed based on the computational algorithm of the dynamic model presented. A case study is presented in the article as a research method. An office building with five above-ground floors and one underground floor was chosen for the case study. To solve the case study, the formwork for horizontal structures (i.e., beams and slabs) is considered. The goal of the case study is to identify research questions and apply time and cost optimization to a selected specific building.

From several countries trend bamboo has been used as a scaffolding material in building projects. Nonetheless, Ethiopia is known for the high population of bamboo vegetation such utilization of the material remained untapped. The purpose of this paper is to identify factors that influence bamboo’s structural suitability as a temporary material and to create a conceptual map for using it as an alternative structural material. Following the identification of important applications influencing parameters via literature analysis, both qualitative and quantitative approaches were used to identify significant factors. The paper also used a series of protocols; at first, several documents were selected based on criteria to provide an overview of bamboo-based construction systems. Following that, four major categories for SWOT analysis were chosen to examine the Ethiopian construction industry’s stance on the use of bamboo as a scaffolding material. Finally, a scoring model was employed as a quantitative analysis protocol to calculate the weight of factors (safety, procedure and implementation, time, and cost) through expert opinions. The investigation revealed that the use of bamboo has a cost and time savings advantage, while an increase in trash at acute and intermittent areas was one of the challenges. Furthermore, one of the challenges in creating bamboo formwork is a lack of complementary joinery techniques. Besides that, it is expected that the bamboo content will fall short of technical requirements. On the Brightside, every single respondent stated unequivocally that bamboo-made formwork meets a low-cost requirement.

Recently, as "Freeform buildings" have increased in number, studies on ways to increase productivity in the construction of freeform buildings are increasing. In the case of 3D printing in construction, many studies are being conducted using the material extrusion method; among the 3D printing methods, manufacturing freeform forms using laminated object manufacturing (LOM) can overcome the limitation presented above. However, there is a lack of cases used in LOM construction sites, so it is necessary to increase the productivity of construction work and study the slicing method suitable for construction. Therefore, in this paper, we propose using study criteria and adaptive slicing methods to combine both the shape error and the manufacturing time of freeform construction. A case study was conducted to verify the results of this study; the freeform concrete form manufacturing with the algorithm that proposed this study could save 66.1% of the manufacturing time compared with CNC milling, and it needs 19.8% less manufacturing time than the existing uniform slicing method. This is a result of the production of one freeform form, and it can be expected to have a greater effect if applied to many freeform forms used in construction sites. In addition, the results of this study can be used as a decision-making tool that can determine the shape and manufacturing time of production according to the on-site situation. [ABSTRACT FROM AUTHOR]

The goal of this paper is to yield insights into the forming, reinforcing, and pouring of concrete buildings, focusing on design, functionality, failure, and safety aspects. The concrete construction process has different moving parts along the form–pour–strip cycle, and the authors aimed to analyze the information pertaining to formwork and rebar design, reasons for failures of formwork and hardening concrete, various hazards on jobsites, and safe work practices. The intent of this study was to seek and analyze the experiences of industry professionals on the above-stated aspects. In total, five well-experienced industry professionals working in concrete forming, reinforcing, and pouring were interviewed. Through comparative analysis of the interview results, the authors were able to gather valuable data related to designs of formwork system and rebars, field practices, jobsite hazards, and safety requirements. Interview results revealed that functionality and applied loads are the determining factors in any design considerations when it comes to formwork system and rebars for concrete buildings. Another finding was that a construction project does not wait for a concrete element to reach its full compressive strength at 28 days before proceeding with the work since the element can hold most construction loads after 3 or 4 days. In addition, the failures which occur in concrete buildings are a result of formwork breakdown, defective formwork layout, and concrete damage due to corroded rebars and inadequate curing procedure. Lastly, interview results revealed that the single leading hazard during concrete works is working at heights which can be minimized using fall arrest systems or engineered guardrails for improved safety. [ABSTRACT FROM AUTHOR]

Beam-Truss wooden joists and stringers have been used extensively in the construction of reinforced-concrete floors in recent years due to their strength and ease of assembly and shuttering. However, the high price of such systems has always been a reason for why they are still not widely used in small-to-moderate-scale projects in developing nations. This high price is due to the high cost of the wood itself and the sophisticated know-how behind their manufacturing process. Hence, there is a need for reducing such costs through using cheaper woods that could be farmed on wastewater and using a simpler technique of manufacturing applicable on a wider scale without sophisticated know-how. This target has been achieved in this research through a truss designed and manufactured from Casuarina Glauca. Casuarina Glauca's mechanical properties were found to be higher than most of the hardwoods but it was not tested in any structural applications before. In this paper, three trusses made of Casuarina Glauca wood were manufactured and tested until failure. The samples withstood loads higher than the design load and deflection and their failure pattern was not catastrophic. Furthermore, the cost of each truss was calculated. A case study was performed in which the developed system was used as joists and compared to two commercially available patented systems. This comparison covered the number of units, the total weight of the joists, and their total costs. The developed system was proven to provide significant cost-savings when compared to the other two. [ABSTRACT FROM AUTHOR]

This article discusses the principle of operation of the sliding formwork, the main elements, the features of measuring and determining the optimal distance between the jacking frames of the formwork system. The principle of operation considers jacks that are used when concreting the formwork, with the help of which they raise the formwork to the desired height for the construction of reinforced concrete structures. It also talks about efficiency especially in the construction of high-rise buildings. In seismic regions, the problem of their reliability and seismic resistance is being solved. Using one set of formwork, by reconfiguring it, the construction of buildings of various planning solutions and different number of storeys is carried out. Given the material from which the sliding formwork is made. The specifics of the operation of manual, hydraulic and electric jacks, with the help of which the formwork is lifted to the desired height. At idle, the forces from the jacking frame and the weight of the formwork adjacent to it are transferred to adjacent jacks. The division of formwork panels according to design features can be divided into large and small panels. Basic formulas for vertical load and distance between jacking rods. [ABSTRACT FROM AUTHOR]

Non‐Waste‐Wax Formwork for customized precast concrete construction – Practical example of the digital manufacturing process for small series of large‐format bollards At the Institute for Structural Design, ITE, fundamental research work has been carried out to develop the non‐waste wax formwork technology, which minimizes formwork waste in the production of freely formed concrete components. This is intended to meet the needs of the precast concrete component industry for technologies to reduce production waste and build low‐emission production lines. The current Eurostars‐funded research project "Robocrete" at ITE together with ODICO Construction Roboctics, Odense, Denmark, and BNB, Beton und Naturstein Babelsberg, is investigating, among other things, processes for the production of large‐format wax block blanks for industrial integration into production lines for small series. The aim is to combine the research results in a digitalized robotic production unit for wax formwork for concrete casting. In previous research, it was not possible to efficiently produce crack‐ and stress‐free wax blocks with a volume of more than 1 m3. For this purpose, optimized methods for the production of wax block are being researched and developed further into a fully digital manufacturing process. In a case study under real conditions of the precast concrete industry with the company Rinn, the wax formwork technology for casting of a geometrically complex concrete bollard 1.2 t of weight was successfully tested. [ABSTRACT FROM AUTHOR]

Copyright of ESTOA: Revista de la Facultad de Arquitectura y Urbanismo de la Universidad de Cuenca is the property of ESTOA Revista de la Facultad de Arquitectura y Urbanismo de la Universidad de Cuenca and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Concrete construction harms our environment, making it urgent to develop new methods for building with less materials. Structurally efficient shapes are, however, often expensive to produce, because they require non-standard formworks, thus, standard structures, which use more material than is often needed, remain cheaper. Digital fabrication has the potential to change this paradigm. One method is Digital Casting Systems (DCS), where the hydration of self-compacting concrete is controlled on the fly during production, shortening the required setting time and reducing hydrostatic pressure on the formwork to a minimum. This enables a productivity increase for standard concrete production. More importantly, though, it enables a rethinking of formworks, as the process requires only cheap thin formworks, thus, unlocking the possibility to produce optimised structural members with less bulk material and lower environmental cost. While DCS has already proven effective in building structural members, this process faces the challenge of moving into industry. This paper covers the next steps in doing so. First, we present the benchmark and expectations set by the industry. Second, we consider how we comply with these requirements and convert our fast-setting self-compacting mortar mix into a coarser one. Third, we present the next generation of our digital processing system, which moves closer to the industrial requirements in terms of size and the control system. Finally, two prototypes demonstrate how DSC: (a) increases standard bulk production by 50% and (b) can be cast into ultra-thin formworks. We discuss the results and the short-term industrial concerns for efficiency and robustness, which must be addressed for such a system to be fully implemented in industry. [ABSTRACT FROM AUTHOR]

A look at the challenges of building the 5th lock chamber in Brunsbüttel The new construction of the 5th lock chamber in Brunsbüttel is currently the largest hydraulic construction site in Europe and is necessary in order to be able to subsequently repair the existing large lock chambers. A benefit‐cost analysis showed the highest benefit value for the new construction between the existing large and small locks, i. e. on the lock island. The location of the construction site results in special requirements for construction operations. In general, a large number of crafts have to be coordinated, which are necessary e. g. for the concrete and steel construction of the heads, the chamber for seagoing vessels and the outer harbours. Furthermore, it has to be taken into account, that the construction site is located at the estuary of the Elbe and thus has to be prepared for storm surges. These special boundary conditions of the construction project and selected construction methods are discussed by way of example. A special focus of the article is also on the extensive concrete technology considerations for achieving durable concrete structures. In addition to minimising crack widths in massive concrete elements, other aspects such as resistance against frost and chloride attack had to be considered for developing the concrete composition. The temporarily limited availability of fly ash made this task even more complex. In order to further improve durability, controlled permeability formwork liners were used in parts of the structure with sever exposure. [ABSTRACT FROM AUTHOR]

In case of construction investments, the cost estimation was always important. The reason for this is that after the planning, the most important issue is the cost of the investment. There are many different estimation methods. These estimates may vary in depth, depending on the task and the plan. The question is what happens if we wanted to predict not only the total cost of the investment but also the cost of some parts and structures. Such a cost element is the formwork cost of the monolithic reinforced concrete structures. This is a special processing aid, which makes it difficult to calculate accurately. The study is based on a cost analysis of the construction of 22 completed buildings over the last 10 years. Here, the cost of the formwork was compared to the total cost of the construction. By examining the 22 buildings together, we made findings over the years. We wanted to find out how much the construction price changes affected the structure and the formwork costs. The other direction of our research was the cost analysis within each building type, focusing on the formwork. In this analysis, we defined six types of buildings, such as detached, dwelling, condominium, public, office buildings, and other types of buildings. This study does not include the cost of the formwork types specific to each component, but from the foundation to the ascending structures, it analyses them in a single system.

Selecting the right construction formwork solution is vital to the success of a construction project. It can help speed up the construction schedule, boost quality, reduce construction costs, and ensure the safety of workers on the construction site. Construction contractors should carefully consider the project’s characteristics and their capacity when selecting the most suitable formwork solution. The Analytic Hierarchy Process (AHP) method is a decision-making tool that can be useful in selecting the best formwork solution for constructing high-rise buildings. The AHP method allows decision-makers to break down complex decisions into smaller, more manageable parts and to evaluate alternatives based on a set of criteria. The paper presents the process and propose the use of the method in selecting formwork options.

Despite the advantageous benefits offered by self-compacting concrete, its uses are still limited due to the high pressure exerted on the formwork. Different parameters, such as those related to concrete mix design, the properties of newly poured concrete, and placement method, have an impact on form pressure. The question remains unanswered on the degree of the impact for each parameter. Therefore, this study aims to study the level of impact of these parameters, including slump flow, T500 time, fresh concrete density, air content, static yield stress, concrete setting time, and concrete temperature. To mimic the casting scenario, 2 m columns were cast at various casting rates and a laboratory setup was developed. A pressure system that can wirelessly and continuously record pressure was used to monitor the pressure. Each parameter’s impact on the level of pressure was examined separately. Casting rate and slump flow were shown to have a greater influence on pressure. The results also demonstrated that, while higher thixotropy causes form pressure to rapidly decrease, a high casting rate and high slump flow lead to high pressure. This study suggests that more thorough analysis should be conducted of additional factors that may have an impact, such as the placement method, which was not included in this publication.