Pneumatic Formwork Research Articles

Terrene 2.0: Biomaterial composites design & shellular structures development for augmented earthen construction

To transition the construction industry towards sustainable practices, we challenge wasteful methods and non-renewable systems by harnessing local biological materials and augmenting them to describe contemporary forms. Our work enhances the primarily compressive material properties of sand-based compounds to develop a construction method for tension–compression anticlastic shellular structures. We have developed a novel bilayer system with multiscale induced behavior called ChitoSand, made primarily of a sand matrix, incorporating chitosan biopolymer as a microstructural binder, short flax fibers to boost tensile capacity at the mesoscale, and citric acid to increase plasticity, which is then underlaid by a sewn burlap fabric base layer to raise the bending capacity at the macroscale. This produces a fully biodegradable material system that we paired with anticlastic geometry calculations to enhance effective material use and structural form. We then developed an earthen construction workflow that uses reusable pneumatic formwork holding the ChitoSand bilayer composite during hardening in ambient conditions. This research yields a tension–compression system with modern geometry and a minimized environmental footprint.

Physical and mechanical modeling of shaping pneumatic formwork by bicubic splines

The article deals with the hierarchical design structure, consisting of four stages of the stress state of pneumatic shells. The main tasks of designing and constructing pneumatic formworks during the construction of thin-walled architectural shells are considered. The introduction of pneumatic formwork into architectural and construction practice has a significant impact on the ability of the architect, builder and designer in the search for new and more advanced forms, as well as the builder in translating the creative ideas of the architect into steel and modern concrete. Thanks to the flexibility and elasticity of the material, it allows the construction of curvilinear spatial shells of a new elastic quality level. The proposed geometric model makes it possible to obtain a variety of software as well as the formation of a discrete-point frame of a finite shape by bicubic splines, which provides a predetermined accuracy for solving subsequent software design and construction problems.

Organizational and Technological Platform for Monolithic Construction Using Pneumatic Formwork

Introduction: The active implementation of digital technologies in various fields, including in the construction industry, leads to the development of technological platforms to sell multiple products. The study examines the prerequisites for the formation of an organizational and technological platform for monolithic construction using pneumatic formwork, which is a set of material and labor resources and organizational and technological solutions that, through their consolidation with modern digital technologies, allow the implementation of construction projects with specified technical and economic requirements. This study aims to systematize various production and construction solutions, presenting them as a unified organizational and technological system that allows for achieving optimal criteria for construction products. Materials and methods: The factors ensuring its effectiveness were selected and systematized to form an organizational and technological platform. A complex system decomposition is presented at three levels of a hierarchical matrix using the analysis of hierarchies. The level of the stages of the life cycle of buildings and structures is taken as the basis, followed by the level of components of the areas of activity that form the platform's effective formation. At the last, lower level, some factors ensure its effective formation. The analysis of the totality of material and labor resources and organizational and technological solutions that make up the platform for constructing monolithic buildings and structures using pneumatic formwork systems was carried out. Results: For an adequate analytical description, it is proposed to use the a priori ranking method, which makes it possible to decompose the indicated factors influencing the effectiveness of the formation of an organizational and technological platform and to obtain specific criteria and alternatives inherent in the construction of monolithic buildings and structures on pneumatic formwork. The detailed development of an analytical apparatus for obtaining an integral assessment will be the subject of further research. Conclusions: The organizational and technological platform for monolithic construction using pneumatic formwork is an innovative tool for interaction between all participants in implementing such projects, aimed at successfully achieving construction design indicators in terms of time and cost and ensuring the required level of reliability and safety of the constructed facility. The novelty of the proposed approach is determined by the combined consideration of material, technological, organizational, and managerial solutions within a single platform to increase the efficiency of construction product production processes. Doi: 10.28991/CEJ-2023-09-11-010 Full Text: PDF

ORGANIZATIONAL AND TECHNOLOGICAL SOLUTIONS FOR THE REPAIR AND RESTORATION OF SEWAGE TUNNELS IN THE PLACES ADJACENT TO EXPLORATION MINES

The analysis of the occurrence of typical accidents of water drainage networks indicates a number of reasons for their failure, namely: a 2-3 times decrease in the amount of sewage over the last 20 years; increase in aggressiveness of wastewater, decrease in flow rate and increase in rainfall. During operation beyond the regulatory term, the reinforced concrete vault of the tunnel is almost completely destroyed as a result of biogenic corrosion. The listed reasons for the destruction of sewage tunnels built more than 50 years ago are generally similar in nature. From the above, it follows that the specifics of the operation of sewer tunnels can be highlighted - the cross-section diameter is more than 1500 mm and the laying depth is more than 5-7 m. It should be noted that the sections of the tunnels at the points of connection with inspection shafts, as well as the structure of inspection shafts, experience the greatest corrosion. A significant role in the repair and restoration of water drainage structures is played by the selection of materials and structures capable of counteracting the aggressive effects of hydrogen sulfide and other gases. In Ukraine and abroad, considerable experience has been accumulated in the repair and restoration of drainage network structures using materials and structures with high acid and alkali resistance. Conducted research has shown that products based on basalt have a number of advantages: high strength, fairly low weight, reliability during operation in a wide temperature range, they are not prone to corrosion and have high chemical resistance. The experience of working with pneumatic formwork gives them special importance, because they ensure the following requirements:quick installation and dismantling of the formwork; the possibility of using it for curved spatial surfaces forms, even with large spans;multiple reversibility of the formwork. The technology for the construction of the vaulted part of the sewer tunnel with internal finishing with stone casting tiles involves the following stages:dismantling of emergency sections of the tunnel (vaults, walls);clearing the tray part of the tunnel;restoration of the section of the tunnel part of the tunnel (if the tunnel is destroyed);cleaning of the existing fittings to ensure the joint operation of the tray and the protective coating of the vault being erected;installation of pneumatic formwork for the construction of the tunnel vault with internal finishing with stone casting tiles;laying stone casting tiles;installation of the necessary fittings for the protective lining of the vault made of monolithic reinforced concrete;creation of inventory formwork;laying the concrete mixture of the monolithic part of the vault;dismantling of pneumatic and inventory formwork after gaining strength of concrete;backfilling of the trench with compaction. The main period of restoration of the observation shaft with the help of lining the walls with stone-cast basalt tiles: dismantling of floor slabs; cleaning of walls from corrosion products; injection of anti-corrosion concrete on a small filler of space at the junctions of the tunnel; reinforcement of the mine walls (in case of deep corrosion of the walls); facing the walls of the observation shaft with stone-cast basalt tiles; treatment of the inner surface of operational areas and stairs with anti-corrosion epoxy polyurethane compound "AQUAKHIM". To justify the feasibility of using the proposed technology, two options for restoring the destroyed tunnel were considered: the method using stone casting tiles; the method of replacing destroyed pipes with polyethylene ones (an open method of restoration with dismantling of the destroyed tunnel). The option of restoring the sewer tunnel using stone casting tiles is almost 3 times more economical and expedient in terms of the cost of materials compared to the use of SPIRO PE pipe. The advantage of restoring sewage tunnels in this way is the durability and resistance of this material to aggressive effects, a sufficient amount of natural material in the country, and low cost. Keywords: sewage tunnel, inspection shaft, basalt, pneumatic formwork, technological solutions, open method.

A Numerical Analysis Model of Composite Pneumatic Formwork Considering the Stiffness Contribution of Polyurethane Layer

Pneumatic formwork is a kind of inflated fabric-polyurethane composite formwork formed by spraying polyurethane on the interior surface of the membrane. A numerical analysis model of composite pneumatic formwork considering the stiffness contribution of polyurethane is proposed to predict the structural response. The analysis model simulates the component of fabric and polyurethane with membrane elements and shell elements respectively, and Tie constraint of surface to surface is defined at the interface. A nonlinear material model for fabric is adopted considering the influence of stress ratio and loading history, and the constitutive relation of polyurethane is described in the foaming plane with different properties for tension and compression. Newton-Raphson incremental iterative method is used to solve the involved nonlinear problems. The simulation accuracy of the proposed analysis model is verified by comparing its predictions with test results about the loaddeformation response of an inflated membrane structure and the corresponding composite pneumatic formwork under horizontal loading. The numerical model is further used to investigate the influence of the thickness of polyurethane layer on the improvement of overall structural stiffness of a larger pneumatic formwork under horizontal fresh gale, and the polyurethane is proved to be beneficial for the shape-control of pneumatic formwork.

PneuPrint: 3D printing on inflatables

This research investigated the feasibility of thermoplastic 3D printing on inflatable membranes. Five experiments were performed in an iterative process through design and manufacture (1), computational simulation and 3D scanning (2), and robotic fabrication on the pneumatic formwork (3). These experiments ranged from small to large-scale 3D printing. Experiment 1 demonstrated the small-scale feasibility of the process and the need to integrate an air-pressure control loop. Experiment 2 investigated the technique transfer from small to large-scale. Experiment 3 analyzed the deviation and shape accuracy of the inflatable membrane. Experiment 4 identified the required fabrication settings and compatibility between the membrane and the 3D printing material. Finally, Experiment 5 demonstrated the design and fabrication potential of large-scale 3D printed elements on pneumatic formworks. The results proved high potential for building freeform design elements for architectural applications on pneumatic formworks.

RECOVERY OF SEWER PIPELINES USING ANCHOR POLYETHYLENE SHEETS

Raising of problem. Microbiological corrosion, which occurs as a result of the vital activity of microorganisms in wastewater, causes the destruction of the vaulted part and significantly reduces the service life of reinforced concrete and concrete drainage pipelines. Partially destroyed pipelines of sewerage networks, operating in various hydrogeological conditions, often at great depths, must be restored using materials that can ensure the reliability of further operation in conditions of microbiological corrosion, cost-effectiveness and ease of repair. These are primarily polymer-based materials. The open method of repair and restoration work on sewer pipelines has significant advantages over trenchless, if their depth is insignificant and urban transport and pedestrian arteries do not interfere with the work. Thus, the development of a technology for repair and restoration of reinforced concrete and concrete collectors destroyed by microbiological corrosion using modern materials based on polymers is an urgent task. Purpose. Development of technology and sequence of repair and restoration work for the restoration of the destroyed vaulted part of sewer reinforced concrete and concrete pipelines by an open method using pneumatic formwork and protective anchor polyethylene sheets. Conclusion. As a result of the research, a technology and sequence of repair and restoration work was developed to restore sewer reinforced concrete and concrete collectors from 5 stages, including the stage of cleaning the collector from corrosion products and destroyed parts, installation of a pneumatic formwork and an anchor polyethylene sheet in the surviving chute part of the collector, installation of metal inventory formwork, restoration by concreting the arch on top of the anchor polyethylene sheet and dismantling of the pneumatic and metal inventory formwork.

Development of Technological Solutions for Sewer Rehabilitation Using Clinker Brick

The aim of the work is to develop a technology for the restoration of damaged sections of sewer collectors using clinker bricks. A significant part of such collectors in the Ukraine has completely exhausted their depreciation resource. For their construction, concrete and reinforced concrete were used, which are subject to destruction as a result of the influence of many factors and, above all, microbiological corrosion. Therefore, the selection of the optimal repair technology using corrosion-resistant clinker brick is relevant. The paper considers the problems of repair and reconstruction of worn-out collectors. Technical and technological solutions of an open method for their recovery using pneumatic formwork and corrosionresistant clinker brick are presented. The design of the collector lining structure has been carried out using the finite element method. To justify the feasibility of using the proposed technology, two options for restoring a worn-out collector have been considered: the “pipe-in-pipe” method and method developed by the authors using clinker bricks. The second option in terms of the cost of materials is almost four times more economical and more expedient than the first one (where polymer materials are used). The advantage of restoring circular sewer collectors by means of laying clinker bricks lies in the durability and resistance of this material (taking into account the anticorrosive composition of concrete) to the aggressive effects of the sewer environment. It should be noted that the application of the developed restoration technology is the most appropriate in conditions of sparse building or outside the city due to the significant volume of earthworks.

APPLICATION OF PNEUMATIC FORMWORK FOR REPAIR AND RESTORATION OF SEWER PIPELINES USING CLINKER BRICK AND POLYMER CONCRETE

Raising of problem. A significant part of wastewater in Ukrainian cities is discharged using sewer collectors with a diameter of 300 to 1 400 mm, the depth of which is within 3…8 m. A significant part of them is destroyed due to corrosion processes that take place in the surface space. Today, the problem of repair and restoration of sewerage networks is becoming especially relevant in connection with the increased requirements for environmental protection. Failure in sewer lines usually results in wastewater infiltration into groundwater and soil. During the repair and restoration of sewage collectors, open and closed methods of work are used. Taking into account that a significant part of sewage collectors passes through areas where there are no transport arteries, through agricultural land and have an insignificant depth of occurrence, and also the fact that their trough part, as a rule, cannot be destroyed due to corrosion, it is advisable to carry out repair and restoration work on them in an open way. Analysis of accidents on sewage collectors, which took place in different cities of Ukraine, showed that, as a rule, due to corrosion, intensive destruction of the roof of the collectors occurs. At the same time, the trough part of the collectors remains intact due to the fact that it is constantly filled with waste water. When repairing such sections of sewerage networks in recent years, operating organizations have been using polyethylene and fiberglass pipes. These smaller pipes are installed in the retained trough part, thus reducing the network diameter. The cost of new pipes is quite high, which in turn increases operating costs. The use of pneumatic formwork allows you to create a new collector, and as the main bearing element, you can use the saved tray part. 
 Purpose. Evaluation of the possibility of using known materials for the manufacture of pneumatic formwork, which will make it possible to carry out repair work to create a new vault using the trough part of the sewer collector as a supporting structure, which will significantly reduce repair costs compared to using pipes made of polymer materials. 
 Conclusion. The investigated samples of materials – fabric Mare 1400 and Hypolon (ORCA 828) – can be used for the manufacture of pneumatic formwork, since laboratory tests made it possible to conclude that there was no adhesion between concrete and material samples.

Development of shell structures in geotechnics and increasing their reliability and safety in modern conditions

In the interests of sustainable development of the country, improving the quality of the living environment of the population, ensuring environmental safety, it is necessary to create scientific and technological potential, which is noted in the Decree of the President of the Russian Federation and the Resolution of the Government. Based on the foregoing, this article discusses the issues of improving shell structures, composite nanomaterials, their reliability, longevity and stability in natural climatic, technogenic, social and environmental factors. A feature of the above shell structures is their ability to maintain their design shape after various influences, which is laid down in the design and technological processes. The use of shell structures made of various composite (fabric, metal-cord and rubber-fabric, etc.) materials was most widespread in the 70s and 80s of the previous century, which is characterized by the creation of various scientific schools: Sergeev B I - soft hydraulic structures; Petrakov B I -pneumatic dams, pneumatic formwork; Blinov Yu I - awning structures; Ermolov - pneumatic building structures; Stepanovich G Ya, - retaining structures for mine workings, etc. Significant successes in the creation of composite materials were made by foreign firms (Japan, Italy, USA, England, etc.).

The Technology of Installation Using Pneumatic Inflatable Formwork

The article is devoted to the current topic of fast-assembled buildings, the analysis of existing technologies, including the use of pneumatic formwork, allows installation both in the urban environment and in special conditions. A crane-free installation technology using pneumatic formwork is proposed, followed by filling the inter-deck space with foam material based on Quad Core.

Ecologically safe construction of monolithic concrete structures

The construction of monolithic concrete vaulted structures technology is proposed. The technology involves in the factory conditions to produce a design based on pneumatic formwork. That allows all processes associated with environmental pollution to be transferred to factory conditions. At the construction site, environmental and human impacts are minimized.

Технология монтажа купольного здания с внутренним деревянным каркасом с использованием пневматической опалубки

The article emphasizes the importance of developing the Arctic and reveals the existing problems of construction in this zone. The existing methods of construction of quick-assembly structures, including the use of pneumatic formwork, are analyzed. A crane-free technology for the construction of a domed building using pneumatic formwork is proposed, with subsequent filling of the inter-deck space with foam material based on Quad Core.

An experimental study on the lateral pressure in foam-filled wall panels with pneumatic formwork

Applications of structural wall panels using flexible formwork systems have recently attracted the attention of architects and engineers. Many of such panelised systems in the market are foam-filled walls, mainly presented in the form of sandwich panels. Knowledge of cast-in-situ induced lateral pressure on the formwork is critical for the economical and safe design of flexible formwork for construction. Formwork cost, on the other hand, comprises a high proportion of the total cost of a building constructed by cast-in-situ materials. Although extensive research has been conducted on the lateral pressure of concrete formwork, the components and mechanics of the lateral pressure in foam-filled walls have not been thoroughly understood. This paper will investigate the lateral deformation, and then lateral pressure on flexible fabric formwork used for construction of polyurethane foam-filled panels. From the lateral pressure on the formwork, the tension forces in the ties are calculated by measuring the compressive force developed between the formwork edges. The results are used for design of intermediate ties for controlling the lateral deformations in an innovative foam filled panelised system, which has been designed for rapid assembly of semi-permanent buildings for post disaster housing.

Pneumatic formwork used in strengthening of structural elements during reconstruction of buildings and structures

The paper discusses the importance of building reconstruction and the need for improving the available formwork systems used for strengthening of structural elements during reconstruction. Citing the results of the analysis of the Russian and foreign scientific publications, the authors emphasize the necessity of replacing costly wooden formworks with high-technology reusable all-purpose and mobile formwork systems. Considering that such requirements are met by rubber-fabric formworks, the authors have developed a pneumatic formwork and showed by way of experiment that the labor intensity of installation and dismantling of such formworks is much lower as compared with conventional wooden formworks, which makes this research original. The paper further describes the design of the suggested formwork and the installation and dismantling techniques. The versatility of the formwork is confirmed by its ability to easily adapt to any structural elements (pier foundations, columns, beams etc.) ensured by the flexibility of rubber-fabric materials. This system can be used for structural elements having various geometric shapes (round, rectangle, trapezoidal) and dimensions. Their transportability is warranted not only by the dimensions and flexibility, but also by a small weight. The use of pneumatic formworks contributes to resolving the problem of conservation such valuable natural material as wood.

Pneumatic Formwork Systems in Structural Engineering

Concrete as a construction material is characterized by high compressive strength, low tensile strength, and good casting ability. In order to fully utilize the potential of this material, the form of load-carrying structures has to be designed according to the stress distribution in the structure. Partially hollow structures, such as hollow beams, or doubly curved structures, such as shells, have favorable characteristics. In hollow structures, material savings are achieved in the individual building components by locally reducing dimensions. Concrete shells, if designed properly, are able to span over large areas by transferring the loads mainly by membrane stresses. The main problem with these structures, however, is the high effort required for producing the complicated formwork. One possibility of reducing this effort is to use a pneumatic formwork. This paper describes different pneumatic formwork systems invented in the past 100 years and presents the latest developments in this area. The many types of possible applications are divided into three categories in order to obtain a clearer overview. Finally, a new construction method, called “Pneumatic Forming of Hardened Concrete (PFHC),” is presented. This method was invented at the TU Vienna and uses the pneumatic formwork in a novel way.

Pneumatic forming of hardened concrete – building shells in the 21st century

AbstractDouble‐curvature shells, used as supporting structures, are strong and save materials. Major parts of the applied loads can be carried by normal forces. Thus, the stresses are distributed very uniformly and efficiently over the entire cross‐section, and long spans can be built with small thicknesses. The state of the art in the construction of shell structures is characterized by a high labour input for formwork and falsework. A new construction method without formwork and falsework has been invented at the Institute for Structural Engineering at Vienna University of Technology. The idea of this new construction method is to build concrete shells with a double curvature originating from an initially plane plate. During the transformation process, the hardened concrete plate is lifted and the elements are bent with the aid of pneumatic formwork until the required curvature is reached. Non‐linear finite element calculations, tension tests, bending tests and bonding tests were carried out in order to determine a suitable combination of concrete and reinforcement. The second part of the paper describes a large‐scale experiment for the erection of a 17.6 × 10.8 m, 2.9 m high free‐form shell. Finally, different applications for the new method are explained.

History and overview of fabric formwork: using fabrics for concrete casting

AbstractThe concept of casting concrete in fabrics, fabric formwork technology, has resurfaced at various times and in different forms throughout the past century. The following paper traces developments that have used fabrics for concrete formwork, including different types of flexible formwork, controlled permeability formwork and pneumatic formwork. This paper presents a comprehensive historical overview of fabric formwork, listing key innovators, technological developments and their advantages, and offering examples of structures built with these methods. The information gathered is used to present a taxonomy of these related formwork technologies as well as a formal definition of the term “fabric formwork” that encompasses them. The paper is intended to introduce readers to these technologies and offer readers already familiar with these methods additional historical background.