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Journal articles on the topic 'Concrete construction Formwork Design and construction'
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1
Li, Yang, and Jian Cai. "Mechanics Analyzing of Suspended Formwork Supporting System and Research of Decision System in Constructing Transfer Storey Structure of Steel Reinforced Concrete." Applied Mechanics and Materials 232 (November 2012): 925–29. http://dx.doi.org/10.4028/www.scientific.net/amm.232.925.
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This article introduced the research of suspended formwork in constructing transfer storey structure of steel reinforced concrete, and the co-working principle of beam and supporting system, and the design theory of suspended formwork method. The author farther founded construction decision system through analytic hierarchy process, and applied in construction site successfully.
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Tierney, Liam, and Md Safiuddin. "Insights into Concrete Forming, Reinforcing, and Pouring in Building Construction." Buildings 12, no. 9 (August 25, 2022): 1303. http://dx.doi.org/10.3390/buildings12091303.
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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.
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Jin, Guo Hui, and Dong Sheng Yu. "Research on Safety of High Formwork Supporting System of Fastener-Style Steel Pipe in Concrete Structures." Applied Mechanics and Materials 578-579 (July 2014): 351–53. http://dx.doi.org/10.4028/www.scientific.net/amm.578-579.351.
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This paper analyzes the safety of high-formwork support system from material quality, computational design, structure erection to construction management system. And putting forward to specific construction safety measures combine with practical engineering. In desire to make the security of high-formwork support systems in concrete structures come true.
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Wang, Li Jiu, Xin Gu, and Dan Sun. "Concrete Structure System Based on Stay in Place Formwork." Advanced Materials Research 160-162 (November 2010): 550–53. http://dx.doi.org/10.4028/www.scientific.net/amr.160-162.550.
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The utilization of stay in place formwork in concrete structure has received considerable attention in recent years. It is comparatively low labor intensity, readily available and has a range of attractive properties and characteristics that makes it suitable for a variety of building and construction applications. The fabrication and seismic behavior was studied in this paper. The experiments have shown that sufficient data have been obtained to give confidence in the reinforcing mechanism of stay in place construction formwork, and future work need only be focused on formwork design and standardization.
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Zhang, Ju Song, An Zhao Sun, and Qian Ling Zeng. "Design and Performance of Polystyrene Modular Composite Dismantling-Free Formwork." Solid State Phenomena 330 (April 12, 2022): 99–106. http://dx.doi.org/10.4028/p-5hz2d9.
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A new type of no-demolition insulation formwork was designed with EPS foam concrete as the frost and fire resistant protection layer and polystyrene board as the insulation layer. Tests were conducted on foam concrete to analyze the flexural performance and safety of the formwork. The results show that EPS foam concrete has excellent performance, and when EPS foam concrete with density grade A08 is used as the protective layer, the mechanical properties of the formwork meet the requirements of "Thermalinsulation free from demolition template for buildings" JC/T 2493-2018, which provides a reference basis for its application in the construction field.
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Kim, Seungho, Dong-Eun Lee, Yonggu Kim, and Sangyong Kim. "Development and Application of Precast Concrete Double Wall System to Improve Productivity of Retaining Wall Construction." Sustainability 12, no. 8 (April 23, 2020): 3454. http://dx.doi.org/10.3390/su12083454.
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The construction of most apartment underground parking lots utilizes reinforced concrete (RC) structures composed mainly of rebar work and formwork. RC structures lower construction efficiency and significantly delay the construction because they require a large number of temporary materials and wooden formwork. In this study, a precast concrete double wall (PCDW) system was developed to address the existing problems of RC structures and to improve the productivity of retaining wall construction. PCDW is a precast concrete (PC) wall in which two thin concrete panels are connected parallel to each other with truss-shaped reinforcement between them. PCDW can contribute to securing integrity, reducing the delay in construction, and improving quality. An overall process for the member design and construction stage of the PCDW system was proposed, and its improvement effects were examined regarding various aspects in comparison to the RC method.
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Hamooni, Morteza, Mojtaba Maghrebi, Javad Majrouhi Sardroud, and Sungjin Kim. "Extending BIM Interoperability for Real-Time Concrete Formwork Process Monitoring." Applied Sciences 10, no. 3 (February 6, 2020): 1085. http://dx.doi.org/10.3390/app10031085.
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The concrete formwork process is a critical component of construction project control because failing to gain the necessary concrete strength can lead to reworks and, consequently, project delays and cost overruns during the project’s execution. The goal of this study is to develop a novel method of monitoring the maturity of concrete and providing reduced formwork removal time with the strength ensured in real-time. This method addresses the wireless sensors and building information modeling (BIM) needed to help project management personnel monitor the concrete’s status and efficiently decide on the appropriate formwork removal timing. Previous studies have focused only on the monitoring of concrete’s status using sensor data or planning the formwork layout by integrating the BIM environment into the design process. This study contributes to extending BIM’s interoperability for monitoring concrete’s maturity in real-time during construction, as well as determining the formwork removal time for project control. A case study was conducted at a building construction project to validate the developed framework. It was concluded that BIM can interoperate with the data collected from sensors embedded in concrete, and that this system can reduce formwork removal time while retaining sufficient strength in the concrete, rather than adhering to the removal time given in building code standards.
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Popescul, Angela, and Serghei Popescul. "Volumetric-Adjustable Formwork for the Construction of Reinforced- Concrete Monolithic Buildings." Intllectus, no. 1 (July 2022): 106–12. http://dx.doi.org/10.56329/1810-7087.22.1.11.
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Reinforced-concrete monolithic buildings offer high seismic resistance due to the lack of joints be-tween load-bearing walls and floors. Thus, the construction of residential, public, socio-cultural rein-forced-concrete monolithic buildings was applied for the first time in Chisinau. A three-dimensional formwork was used as technological equipment, designed for simultaneous pouring of concrete into vertical walls and floors, forming an integral construction. The formwork is made in the form of flat panels or large U-shaped and L-shaped sections, joined by a mechanism of approach and extension to the design dimensions of the concrete room. After the concrete hardens, the structure is transferred by a crane for successive concreting of the next floors.
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Wu, Qiong, Xue Hui An, and Mian Song Huang. "Cheap Mix Design of the Rock-Filled Concrete Materials." Applied Mechanics and Materials 470 (December 2013): 802–6. http://dx.doi.org/10.4028/www.scientific.net/amm.470.802.
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Rock-filled concrete (RFC) is an innovative dam construction material that has been developed quickly in China since 2003. The concrete is produced by pouring the Self-compacting concrete (SCC) into the voids of large rock chunks, with a minimum size of 300 mm, in a formwork. To date, all the practical applications have shown that using RFC in dam constructions has significant economic and environmental benefits. Total construction cost is reduced due to using large amount of rock chunks, which can amount to roughly 55% of the total volume of RFC. When producing SCC, we make full use of local raw materials (e.g. fly ash, limestone) and optimize mix design based on the simple mini-slump flow tests on pastes to obtain better workability and lower cost. SCC with excellent workability can be obtained even the powder material is limestone powder alone. It is indicated that RFC is a potential and promising material for use in future concrete dams.
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Lee, Dongmin, Taehoon Kim, Dongyoun Lee, Hyunsu Lim, Hunhee Cho, and Kyung-In Kang. "DEVELOPMENT OF AN ADVANCED COMPOSITE SYSTEM FORM FOR CONSTRUCTABILITY IMPROVEMENT THROUGH A DESIGN FOR SIX SIGMA PROCESS." JOURNAL OF CIVIL ENGINEERING AND MANAGEMENT 26, no. 4 (April 9, 2020): 364–79. http://dx.doi.org/10.3846/jcem.2020.12188.
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System form is widely used when constructing concrete buildings and structures because it has high productivity and good concrete casting quality compared with traditional hand-set form. However, from a worker’s perspective, system form is still very harsh to handle because of its heavy weight, noise generation, and use of releasing agent, and it also attenuates the productivity of system formwork. Therefore, this study proposes the use of an advanced composite material-based concrete form for workers using a Design for Six Sigma (DFSS) process to improve constructability of system formwork. User requirements are systematically reflected in the technical characteristics of concrete form, and innovative principles are scientifically organized through the DFSS process that mainly consists of quality function deployment and theory of creative problem-solving methods. The proposed composite form showed improved performance in deriving high-quality formwork and worker-friendly working conditions compared with previous system forms. Additionally, this study demonstrated how the DFSS will be a valuable tool for technology development and systematic decision-making in building construction.
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Dong, Chen, Chen Ming, Cai Ouyang, and Li Pengkun. "Study on mechanical properties of a new type of prefabricated GRC mold shell." E3S Web of Conferences 136 (2019): 02030. http://dx.doi.org/10.1051/e3sconf/201913602030.
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The GRC formwork structural column adopts the factory-based vertical prefabrication production process, which can reduce the floor space, reduce the formwork loss, speed up the construction progress, promote the full decoration of the prefabricated building, and improve the efficiency of the assembly construction. major. In order to optimize the production process of prefabricated GRC formwork column, the overall stress system of GRC formwork structure is analyzed in the concrete pouring process, and the thickness of GRC formwork, the number of steel hoops and the GRC mode are considered. The influence of the shell cross-section size on the mechanical properties. The research results can provide reference for the optimization and design of prefabricated GRC formwork column production process.
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Schleicher, Simon, and Michael Herrmann. "Constructing hybrid gridshells using bending-active formwork." International Journal of Space Structures 35, no. 3 (June 16, 2020): 80–89. http://dx.doi.org/10.1177/0956059920924189.
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Aiming to promote a more sustainable approach to material utilization in architecture, this article presents an alternative construction method for lightweight and efficient concrete structures. The strategic focus is placed on building wide-spanning roof structures like vaults, domes, and freeform shells with the lowest possible input of raw materials and energy. To achieve this objective, the article explores the novel idea of using bending-active structures, made from millimeter-thin carbon fiber strips, as lost formwork and structural reinforcement for the production of hybrid gridshells. After a general introduction to the state-of-the-art in concrete construction, the authors discuss opportunities and challenges related to flexible formwork designs and their possible impacts on the building industry. Relying on the example of a built prototype, the authors present a promising design methodology and analyze the gridshell’s geometrical and structural characteristics throughout different stages of the construction process. The article concludes by discussing the added value of this research and identifying the key aspects that need to be considered in the further development of this construction method.
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Yang, Yabin, Xinxin Ding, Yungao Liu, Lianchao Deng, Feiyang Lv, and Shunbo Zhao. "Lateral Pressure Test of Vertical Joint Concrete and Formwork Optimization Design for Monolithic Precast Concrete Structure." Buildings 12, no. 3 (February 23, 2022): 261. http://dx.doi.org/10.3390/buildings12030261.
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When the vertical joints of monolithic precast concrete structures are cast by self-compacting concrete, the design of the formwork under rational lateral pressure of self-compacting concrete becomes a key technical issue. In this paper, a prototype simulation test was conducted for the pouring of self-compacting concrete in the vertical joint of precast concrete walls. The self-compacting concrete was continuously poured from the top of vertical joints with a height of 2.8 m without any assistance such as a delivery tube. The formwork pressure of self-compacting concrete was measured at different heights with varying casting time. Results showed that the lateral pressure increased with the increase in slump-flow of fresh self-compacting concrete, reaching a peak value of about 70 kPa at a height of about 600 mm from the bottom of formwork. Compared to the concrete with a slump-flow of 550 mm, the self-compacting concrete with the slump-flow reached 655 mm and 755 mm, presenting an increase in the peak lateral pressure by 31.5% and 44.9%, respectively. A method for calculating the lateral pressure of self-compacting concrete on the joint formwork is proposed using the analysis of enveloped test curves. Under the condition with enough strength and limited deformation of the joint formwork, the optimal design of aluminum alloy formwork is determined using finite element analysis. This provides a sci-tech foundation of the optimal design to lighten the weight of joint formwork to improve the installation efficiency and reduce the manual power cost.
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Yakovleva, Irina, and Valentina Kurochkina. "Arrangement of construction joints in cast-in-place slabs." E3S Web of Conferences 97 (2019): 04023. http://dx.doi.org/10.1051/e3sconf/20199704023.
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Within latest decades cast-in-place construction of residential houses has been actively developed. Works on erection of cast-in-place frame of the building are normally performed by phases, which results in a necessity to arrange construction joints of concreting. In accordance with regulatory documents, it is allowed to arrange construction joints in any place of the slab, in parallel with its less side. As well, it is necessary to observe the technology for joint arrangement. As practice shows, observing only technology of construction joint arrangement is insufficient to provide for strength properties of cast-in-place reinforced-concrete slabs. This article provides an analysis of actual geodetic pre-construction surveys, design and theoretically-calculated solutions; case study is a multistoried building under construction. On which basis, excessive slab deflections in the places of construction joints, were detected. It is established, that the main reason for deflection occurrence is early removal of slab formwork and installation of supports for temporary supporting. On the basis of obtained findings authors make conclusions regarding compulsory observance of the technology for construction joint arrangement, regarding a necessity to remove formwork according to common standards 70.13330.2012; as well, it is recommended to leave formwork under construction joints until concrete gains 100% of ruggedness.
15
Rady, Mohammed, Sameh Youssef Mahfouz, and Salah El-Din Fahmy Taher. "Optimal Design of Reinforced Concrete Materials in Construction." Materials 15, no. 7 (April 2, 2022): 2625. http://dx.doi.org/10.3390/ma15072625.
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The structural design process is iterative and involves many design parameters. Thus, this paper presents a controlled framework for selecting the adequate structural floor system for reinforced concrete buildings and efficiently utilizing the corresponding construction materials. Optimization was performed using an evolutionary algorithm to minimize the total construction cost, considering the costs of concrete, steel reinforcement, formwork, and labor. In the problem formulation, the characteristic compressive strength of concrete was treated as a design variable because it affects the mechanical performance of concrete. The design variables included the column spacings, concrete dimensions, and steel reinforcement of different structural components. The constraints reflected the Egyptian code of practice provisions. Because the choice of the structural floor system affects the design details, three systems were considered: solid slabs, flat slabs with drop panels, and flat slabs without drop panels. Two benchmark examples were presented, and the optimal design results of the structural floor systems were compared. The solid slab system had the lowest construction cost among the three structural floor systems. Comparative diagrams were developed to investigate the distribution of construction costs of each floor system. The results revealed that an adequate choice of design variables could save up to 17% of the building’s total construction cost.
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Gelbrich, Sandra, Henrik L. Funke, Andreas Ehrlich, and Lothar Kroll. "Flexible fiber-reinforced plastic formworks for the production of curved textile-reinforced concrete." Advances in Structural Engineering 21, no. 4 (October 5, 2017): 580–88. http://dx.doi.org/10.1177/1369433217732681.
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A new constructive and technological approach was developed for the efficient production of large-dimensioned, curved freeform formworks, which allows the manufacturing of single- and double-curved textile-reinforced concrete elements. The approach is based on a flexible, multi-layered formwork system, which consists of glass fiber–reinforced plastic. Using the unusual structural behavior caused by anisotropy, these glass fiber–reinforced plastic formwork elements permit a specific adjustment of defined curvature. The system design of the developed glass fiber–reinforced plastic formwork and the concrete-lightweight-elements with stabilized spacer fabric was examined exhaustively. Prototypical curved freeform surfaces with different curvature radii were designed, numerically computed, and produced. Furthermore, the fabric’s contour accuracy of the fabric was verified, and its integration was adjusted to loads. The developed textile-reinforced concrete had a high three-point bending tensile strength. Beyond that it was ensured that the textile-reinforced concrete had a high durability, which has been shown by the capillary suction of deicing solution and freeze–thaw test with a low amount of scaled material and a relative dynamic E-modulus of 100% after 28 freeze–thaw cycles.
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BILOKON, A. I., T. A. KOVTUN-HORBACHOVA, and O. A. KАPSHUK. "TECHNOLOGICALITY OF FORM SYSTEMS AT DIFFERENT METHODS OF CONCRETE PREPARATION." Ukrainian Journal of Civil Engineering and Architecture, no. 4 (November 21, 2021): 17–23. http://dx.doi.org/10.30838/j.bpsacea.2312.310821.17.786.
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It is shown that many scientific publications and researches in the field of monolithic house-building aredevoted to increase of efficiency of use of formwork systems as the most labor and economically expensive area. It isnoted that up to 50 % of the costs are for formwork, including the cost of renting or purchasing, its installation,maintenance, storage and remuneration. It is presented that with the development of formwork systems their technologyis improved, in particular the regulatory framework is improved to reduce the complexity of the work, adjustments aremade to the size of the formwork, it becomes more uniform, reduces the number of connections, increases the turnoverof formwork systems, which also reduces costs.It is shown that a very important issue, inseparable from monolithichousing is the improvement of design with the composition of concrete and concrete mixtures. One of the promisingУкраїнський журнал будівництва та архітектури, № 4 (004), 2021, ISSN (Print) 2710-0367, ISSN (Online) 2710-0375 17 areas of technology improvement is to reduce the time of the set of design strength. The question of the accelerated setof durability by concrete at hardening is very actual in the conditions of the market and high cost of rent of a timbering.Predicting the accelerated growth of concrete strength, respectively, will establish the morning timing of removal offormwork systems. The graph of dependence of time of a set of durability by concrete, for example at activation ofcement suspension in an electromagnetic field in comparison with standard data of hardening is specified. The reductionof the term (days) of keeping concrete in the formwork is shown, it improves the manufacturability of its use,accordingly it causes a reduction of all costs, incl. reduction of construction time and, accordingly, acceleratedmovement of funds and economic profit due to the earlier commissioning of facilities.The area of perspectiveresearches on establishment of interrelation of indicators of efficiency from parameters of object and technology isformulated. This gives a theoretical justification for further computational experiments. The object of research is theproduction processes with the use of collapsible formwork systems for frame-monolithic construction. The subject ofthe study are indicators of manufacturability of the use of formwork systems. The purpose of scientific and appliedresearch is the ability to show the increase of manufacturability of construction by ensuring the normative turnover offormwork by intensifying the hardening of concrete in frame-monolithic construction with a reduction in the duration ofthe strength of concrete. As a result of research the following tasks were defined: the area of further researches isformulated, ways of reduction of the basic technical and economic indicators are offered, the expedient theoreticalsubstantiation of the further computational experiments is proved.
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Song, Xiao Ruan, Yu Ting Qu, Xiao Yun Zhang, Wei Niu, and Yu Feng Jiang. "Design and Analysis of the Support System for Cement-Base Formwork." Advanced Materials Research 374-377 (October 2011): 1249–53. http://dx.doi.org/10.4028/www.scientific.net/amr.374-377.1249.
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The cement-base composite formwork reinforced by FRP is developed to act as permanent construction formwork. Considering such properties as the minor stiffness out of the plain and the smaller bending resistance of the formwork, the matched cross support device is designed which can be recycled. In this paper, components of the support device and the corresponding functions are introduced, the technological process is described. By means of finite element program, the appropriate support distances of formwork during concrete placement are calculated, the stress and deformation performances are also analyzed. In the end, economic benefit and environment efficiency of the permanent formwork system are discussed. The above research results indicate the feasibility and economy of the support system, which present a gist for investigation and application of the permanent FRP cement composite formwork.
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Leach, Neil, Anders Carlson, Behrokh Khoshnevis, and Madhu Thangavelu. "Robotic Construction by Contour Crafting: The Case of Lunar Construction." International Journal of Architectural Computing 10, no. 3 (September 2012): 423–38. http://dx.doi.org/10.1260/1478-0771.10.3.423.
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Contour Crafting is a digitally controlled construction process invented by Professor Behrokh Khoshnevis that fabricates components directly from computer models, using layered fabrication technology. By obviating the need for formwork used in traditional concrete construction, CC can reduce costs and construction times significantly. The technique has great potential as a robotic form of construction reliant on relatively minimal human labor as a form of construction in relatively hazardous environments, such as the Moon with its radiation levels that can prove highly damaging. Current research funded by NASA has been exploring the potential for using CC on the Moon to build structures making use of readily available regolith that is found in great abundance on the surface of the Moon. This article offers an overview of this research and evaluates the merits of using CC on the Moon.
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Li, Jian Ping, Jie Ruan, Pin Tan, and Xian Jun Wang. "Simulation Analysis and Structure Optimization of Steel Structure Climbing Formwork with Material Properties Used in the Large Angle Leaning Bridge Tower." Applied Mechanics and Materials 540 (April 2014): 201–4. http://dx.doi.org/10.4028/www.scientific.net/amm.540.201.
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Steel structure climbing formwork has been widely used in bridge pier and bridge tower, etc. But the design of 30 degrees slope climbing formwork design is rarely involved. The climbing formwork which in the upper surface of leaning bridge tower is affected by concrete buoyancy and the downside is affected by concrete gravity .That cause insufficient stiffness,deformation of the template,non-uniform cross-section of the bridge and large angle deviation which have great harm to the bridge quality .This paper which combined the construction project of Huaibei Xiangwang Bridge establish the mode of climbing formwork, then, import the mode to the Workbench14.5 proceeding simulation analysis. Getting the stress and deformation of the climbing formwork, check the strength and stiffness .Then optimize the structure of climbing formwork to ensure the stiffness and control the deformation of the template. The stress of downside climbing formwork after optimization is uniform and maximum stress is reduced about 30% .This paper provide a reference to the design of the climbing formwork used in the large angle leaning bridge tower.
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Abreu, Marina Macedo de, and Alberto Casado Lordsleem Jr. "Aluminum formwork system: loss and productivity." Built Environment Project and Asset Management 9, no. 5 (November 11, 2019): 616–27. http://dx.doi.org/10.1108/bepam-04-2018-0070.
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Purpose The purpose of this paper is to establish and evaluate the concrete loss and labor productivity (LP) indicators in the concreting step of aluminum formwork system (AFS) in construction in Brazil. The loss and productivity indicators are directed to a regional database (Pernambuco, Brazil). Design/methodology/approach Case study was selected as the most appropriate approach. The methodology included data collection in the construction project with 10 residential towers of 320 apartments, in the city of Jaboatão dos Guararapes, Brazil, throughout 82 concrete pouring days using 415 concrete mixer trucks, with a total of 2,582.50 m3 of concrete. Findings The findings identified an average concrete loss of 2.6 percent and the LP indicator varying between 0.15 and 0.97 WH/m3. It could be verified that the loss indicators were influenced mainly by the learning effect associated to the qualification of the labor. In addition, the productivity indicators were strongly influenced by delays at the beginning of the concrete pouring and by problems coming from the sequence of concrete supply. Originality/value LP indicators are still literature restricted, especially considering only the concreting step. The direct observations of this study allow the identification of factors that inhibit productivity. The comparison of indicators for the concreting service between the ASF and the conventional system attests to the speed, low cost and efficiency of the system studied in this paper.
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Hu, Chang Ming, Feng Yun Liu, Jia Ling Che, Yun Bo Zhao, and Qiong Wu. "Design and Field Measurement Analysis of Steel Template in Axis Rotating Structures." Applied Mechanics and Materials 368-370 (August 2013): 1518–25. http://dx.doi.org/10.4028/www.scientific.net/amm.368-370.1518.
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The template system, the mould of fresh concrete, plays an important role in the concrete structure construction. At present, in the process of steel template concreting in axis rotating structures, the template system adopts the traditional construction technology of formwork with scaffolding; thus, the template can not withstand the loop force, hence difficult construction and safety hazards. Aimed at the deficiencies in template system design, a new kind of steel template that can bear loop force has been designed with the software ANSYS. Taking a rotating structure as an example, this paper, based on the stress test of the structure, has analyzed the distribution and change of the stress under the steel template construction. The results show that the design of the template is reasonable and that it is also applicable to similar structures.
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Kovářík, Michal, Pavel Svoboda, and Henri Hubertus Achten. "Limits and Potential of 3D Printing Technologies for Construction of Concrete Shells." Solid State Phenomena 292 (June 2019): 249–56. http://dx.doi.org/10.4028/www.scientific.net/ssp.292.249.
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Concrete shells are a very effective type of building structures due to their ability to bridge large spans with minimal construction thickness. This type of building structures built on the medieval vaulting techniques and, regarding the use of reinforced concrete over the last 100 years, it has overcome the limitations of the masonry vaulting technologies and enabled to increase the span of structures to tens of meters. The construction technology to realize concrete shells using monolithic casting into formwork is besides abovementioned advantages characterized by high labour and thanks to the cost and manufacturing intensity of double curved formwork panels it allows economical realization of only selected structural geometries. Its considerable limitation is, besides the costly production of double curvature formwork, also the laborious installation of formwork and falsework structures. The solution seems to be in line with the upcoming transition to Construction 4.0 robotizing the construction technology of shells that could create a similar increase in productivity and design possibilities as was the technological transition between vaults and shells. One of the promising technologies of robotic production seems to be digital fabrication methods and, in particular, 3D printing or in other words additive manufacturing. This wasteless technology, which has been used to date for experimental projects mainly for the realization of vertical bearing structures, has, despite the first attempts at realizing vaults, a number of technological limitations. In this article, authors aim to summarize and indicate possible constraints of on site 3D printing of domes. They further indicate the possible ways to overcome these limitations and suggest two different means of on site 3D printing of hemispherical dome and the dome based on the catenary profile using extrusion nozzles with different profiles. Finally they discuss the Eurocode requirements for concrete shells and suggest technological solutions for on site 3D printed shells in terms of structural reinforcement.
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Zhou, Shuang Xi. "Preparation and Application of a Self-Thermal and Insulation-Ribbed Floor." Applied Mechanics and Materials 353-356 (August 2013): 2896–99. http://dx.doi.org/10.4028/www.scientific.net/amm.353-356.2896.
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With the cementitious composite formwork without being removed, steel wire frame and formwork technology, a self-thermal and insulation-ribbed concrete floor is made. Through the tests of bend-bearing capacity of self-thermal and insulation-ribbed floor, the results show that the loads of the self-thermal and insulation-ribbed floor meet the limits on deflection requirements according to the design of concrete structures. Besides, the floor has a better thermal and soundproof function compare to the ordinary concrete beam and slab, and its comprehensive cost of construction is low.
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Ghulyan, Armine B., Garegin L. Tepanyan, and Boris J. Sargsyan. "Problems of Formation of Complex Monolithic Reinforced Concrete Structures." Key Engineering Materials 828 (December 2019): 153–57. http://dx.doi.org/10.4028/www.scientific.net/kem.828.153.
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The features of the structures of complex monolithic reinforced concrete structures are given, the necessity of their organizational and technological design to ensure quality, reduce the duration and safety of construction and installation works is substantiated. A fragment of the formwork for complex curvilinear beams is presented, where the permanent and temporary loads, the permitted steps of the main and secondary beams and remote scaffolds for the PERI and CRAMOS modular formwork systems, which are more common in RA, are calculated in detail.
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Li, Guangjun, Tianfang Mo, Ningbo Xu, Weixiong Zhang, Hanwen Lu, Deyuan Deng, and Mingbo Yi. "Subsection construction technology of rectangular concrete independent column with super high cross section." E3S Web of Conferences 293 (2021): 02004. http://dx.doi.org/10.1051/e3sconf/202129302004.
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With the progress of engineering technology, the ability of design and construction has been significantly improved, which the number of long-span construction and long-span Bridges and long-span steel structures are increasing more and more. As the main supporting members of Bridges and steel structures, the quality assurance of rectangular reinforced concrete independent columns is particularly important. In the implementation process of No.18 Maintenance Hangar Project of GAMECO Aircraft Maintenance Facility Phase III in Guangzhou Baiyun International Airport of China Southern Airlines, through research and practice, our company applied the subsection construction technology of super high section rectangular concrete independent columns, which can not only guarantee the quality and forming effect of the column body, but also reduce the input of formwork materials. Improve the utilization rate of formwork and scaffold effectively, and then reduce the input of turnover materials, and achieve remarkable results.
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Elnabelsy, Gamal, and Murat Saatcioglu. "Seismic behavior of concrete bridge columns confined with fiber-reinforced polymer stay-in-place formwork." Advances in Structural Engineering 21, no. 4 (October 12, 2017): 613–23. http://dx.doi.org/10.1177/1369433217732670.
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One of the applications of fiber-reinforced polymers in bridge construction is stay-in-place formwork. Fiber-reinforced polymer stay-in-place formwork, in the form of preformed tubes, provides easy form assembly, protection of steel reinforcement and concrete against corrosion and chemical attacks while also improving the strength and ductility of structural elements in earthquake resistant construction. Experimental research was conducted to investigate the seismic performance of fiber-reinforced polymer stay-in-place formwork for bridge columns. Tests of large-scale specimens were conducted under simulated seismic loading. The experimental program included circular and square columns confined with carbon fiber–reinforced polymer tubes. The results indicate that the use of carbon fiber–reinforced polymer tubes increases column inelastic deformability significantly. Bridge columns under low levels of axial compression exhibit inelastic drift capacities in excess of 4% before failing in flexural tension due to the rupturing of longitudinal reinforcement. These observations and experimental results were used to develop a displacement-based design procedure for concrete confinement for fiber-reinforced polymer–encased concrete columns. This article presents an overview of the experimental program and the design approach developed.
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Kigoye, Eriya, and Michael Kyakula. "Load Deflection Relationship of a Solid Slab under the Action of Construction Loads." Advances in Civil Engineering 2022 (March 9, 2022): 1–16. http://dx.doi.org/10.1155/2022/3125920.
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Over the past decades, there has been a tremendous improvement in the concrete placement technology in Uganda. The methods have moved from being manual to the use of concrete pumps. A concrete pump is capable of pumping high volumes of concrete per minute. This implies that for small volume slabs before the setting of concrete, the whole weight of the fresh concrete of the upper slab, formwork, and props is transferred to the lower supporting slab. During construction, slabs are stacked with materials like bricks, blocks, sand, and aggregates. Construction loads such as block loads and loads due to props, formwork, and freshly cast solid concrete slabs on the lower floor are usually greater than the imposed loads and are not catered for in design. A baseline survey carried out on 118 randomly selected sites in Kampala revealed that in 87% of the cases, supports are removed from a lower reinforced concrete slab, and then props are put on its top to support a yet to be cast slab on an upper floor. It also revealed that 80.6% of the slabs had construction loads such as bricks, blocks, sand, timber, and aggregates. Deflections were measured using dial gauges for construction loads owing to freshly cast slab and concrete blocks in a physical model of a multistory structure with dimensions of 4 m long, 2 m wide, 2 m high to 2nd level, and 2 m to 3rd level. Loads due to freshly cast concrete were 158% more than unfactored design live loads. The maximum deflection at center of the slab due to a freshly cast slab and blocks loaded instantly was 1.15 mm and 11.815 mm, respectively, compared to the immediate deflection equal to 0.103 mm due to a design-imposed load of 2 KN/m2.
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Singh, Manav Mahan, Anil Sawhney, and Vaishnavi Sharma. "Utilising Building Component Data from BIM for Formwork Planning." Construction Economics and Building 17, no. 4 (December 7, 2017): 20–36. http://dx.doi.org/10.5130/ajceb.v17i4.5546.
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Advancements in the computing realm have assisted the Architecture, Engineering, and Construction (AEC) industry to progress significantly by automating several design tasks and activities. Building Information Modelling (BIM) authoring tools have played a significant role in automating design tasks and reducing the efforts required by the designer in redundant, repetitive or production-oriented activities. This paper explores one such approach that, with the help of BIM authoring tool and its Application Programming Interface (API), reduces the efforts expended on formwork design for concrete structures. The paper utilises the concept of using BIM data as input to compute the quantity of formwork, and generate visualisations and schedule of formwork. The developed approach first takes data input from semantic BIM to the API environment for computation and design of formwork systems, which is then placed within the BIM model, to generate visualisation and prepare schedules. The research work utilises a structural concrete wall as an example to demonstrate the presented approach. The approach will be influential in streamlining the formwork design process in the BIM environment and reducing efforts required by the designer and the planning engineer. Since the formwork elements are generated as 3-Dimensional (3D) solids and smart BIM elements, the generated model of formwork can be used for resolving clashes, scheduling, and resource planning.
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Meng, Xian Hong, Chan Fang Zhou, and Jing Hai Zhou. "Lattice Concrete Wall Structure Optimization and Numerical Analysis." Applied Mechanics and Materials 71-78 (July 2011): 1628–32. http://dx.doi.org/10.4028/www.scientific.net/amm.71-78.1628.
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Polystyrene formwork of lattice concrete wall is a set of lightweight, insulation, sound insulation, fireproof, bearing multi-function in one of the "EPS new energy-saving" wall structure system. Through the polystyrene formwork structure forms of optimized improvement built in construction process of collapse produced high wall plate phenomenon. Do an axial compression ratio of 0.2 lattice specimens of reinforced concrete shear wall in axis pressure and reciprocating level forces test. The damage form of that wall for wall bottom beam-column central cross core ring crack and appear "X" type crack and are crushed. The mesh wall formed strong vertical limb and weak horizontal limb，belongs to the ductility structure , and has more yield , and energy dissipation capacity , and wall overall performance is strong , and avoid brittle failure , and has good ductility、deformation ability and bearing capacity of the characteristics of big .The finite element analysis and experimental results indicated that the ultimate bearing capacity of the wall are the same. For new formworks do wall by finite element analysis, in do not affect its aseismic capacity premise that wall structure forms are optimized design.
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Hou, He Tao, Yan Fei Sun, Jian Zhou, Zhong Long Lv, and Jing Jing Li. "Design and Application of Lightweight Steel Residential House." Applied Mechanics and Materials 353-356 (August 2013): 2851–56. http://dx.doi.org/10.4028/www.scientific.net/amm.353-356.2851.
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This paper presented a design of a steel residential house. H-shaped steel was chosen as the beam and column of the steel frame. End-plate joints and welding node joints were used to connect each other so that the structure could be constructed rapidly and conveniently. PK prestressed concrete composite slab was chosen as the floor and roof slab. PK slab could be produced in factory and dont need formwork assembling and setting and could reduce the amount of work on-site, and could shorten the period of construction effectively. Composite panels with steel truss reinforced concrete and bamboo reinforced ceramic concrete were chosen as exterior walls. Compared with aerated concrete block wall with external insulation, composite panels had the advantages such as lightweight, energy saving, rapid installation, less slit and small thickness of wallboard and better seismic behavior. Application of the technology made the steel residential house a lightweight, energy saving and rapid construction house.
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Pulyaev, I. S., and S. M. Pulyaev. "HARDENING CONCRETE IN STRUCTURES: CHOICE OF THE CONSTRUCTION METHOD BASED ON RESULTS OF THE TEMPERATURE REGIME MODELING IN SPECIAL CONDITIONS." Russian Automobile and Highway Industry Journal 16, no. 4 (September 8, 2019): 486–503. http://dx.doi.org/10.26518/2071-7296-2019-4-486-503.
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Introduction. The paper discusses the use of different methods of the hardening concrete’s temperature regime, depending on the boundary conditions specified in the design and construction of the object. Such conditions include the temperature regime of concrete holding, the turnover rate of the formwork and the construction time of the facility, as well as other factors. The aim of the research is a compilation of the various methods of investigation of the temperature regime of hardening concrete, aimed at providing the required timing of the formwork and technological equipment turnover to ensuring the consumer properties of the structures. The scientific novelty of the research lies in the updating and testing of methods for regulating the hardening concrete’s heating, ensuring the formation of the required consumer structures’ properties not previously used in transport and civil construction and based on preliminary modeling of thermal processes occurring in the hardening concrete through the calculation software. The authors on the example of several large objects’ construction consider the most common situations associated with the selection of construction technology in difficult natural conditions by taking into account the required consumer properties: concreting of large-mass structures in a limited time in the warm season and low-mass structures in winter concreting. The research is relevant in view of the large-scale construction in our country as well as of the facilities’ reconstruction.Materials and methods. The authors carried out the research with the use of modern settlementmeasuring and analytical systems taking into account the change in the thermal stress state of hardening concrete as a function of the temperature change of the concrete mix over time. The use of the modern computational and analytical complex in the physical modeling of the thermo physical processes of hardening concrete made it possible to obtain results as accurately as possible and comparable with observational data obtained during the construction process.Results. The results allowed authors to project the objects’ concreting of erected in various predetermined conditions while observing the required terms of formwork turnover and ensuring the necessary consumer properties.Discussion and conclusions. The authors propose measures, the implementation of which makes it possible to build complex construction projects in a short time in special climatic conditions. The paper is useful for engineering and technical personnel and for professionals involved in the study of thermal processes of hardening concrete.
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Mosallam, K. H., and W. F. Chen. "Design considerations for formwork in multistorey concrete buildings." Construction and Building Materials 6, no. 1 (March 1992): 23–30. http://dx.doi.org/10.1016/0950-0618(92)90024-s.
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Pandhare, Sachin J. "3D printing-A Review of Materials, Applications, and Challenges." International Journal for Research in Applied Science and Engineering Technology 9, no. 12 (December 31, 2021): 58–67. http://dx.doi.org/10.22214/ijraset.2021.39174.
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Abstract: Now a days 3-Dimensional Printing (3DP) technology is used world widely and it can actually print each and every thing with the desired computer program. In Construction engineering the challenges are like availability of skilled man power, time constraint, cost effectiveness and complicated shapes etc. But with the help of an automated machine, the 3D printing technology, has huge potential to have faster and more accurate construction of complex and more laborious works. This technology can build three-dimensional (3D) objects by connecting layers of materials and can be applied to convert waste and by-products into new materials. The 3DP in concrete construction is increasing thanks to its freedom in geometry, rapidness, formwork-less printing, low waste generation, eco-friendliness, cost-saving nature and safety. This paper attempts to review the digital printing technology introduced in the construction industry and the also highlights the impact on concrete technology. It also discusses about the materials used in 3DP, mix design, various applications and challenges in the construction industry. Keywords: 3D printing, Concrete, 3DCP, Mix design.
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Terzioglu, Taylan, Gul Polat, and Harun Turkoglu. "Analysis of Formwork System Selection Criteria for Building Construction Projects: A Comparative Study." Buildings 11, no. 12 (December 6, 2021): 618. http://dx.doi.org/10.3390/buildings11120618.
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The formwork system (FWS) in reinforced concrete (RC) construction is a critical component. The appropriate FWS is selected based on a number of conflicting and compromising criteria, and the selection of the FWS is carried out by construction professionals with different technical and/or administrative backgrounds. The perspectives and perceptions of construction professionals and companies involved in the FWS selection process may vary depending on their motives. In addition, some building structural parameters may have a significant impact on the FWS selection criteria. Most of the former studies investigated the FWS selection criteria from only the perspective of contractors and neglected the potential differences in the perspectives and perceptions of different construction professionals (i.e., owners (CO), project managers (PM), construction managers (CM), site engineers (SE), planning engineers (PL), procurement engineers (PR), technical office engineers (TO), and formwork design and/or formwork sales engineers (FD/FSL)) and companies specialized in different fields (i.e., project management service (PMS), engineering and design (ENG/DSG), formwork and scaffolding (FW/SCF), and general and/or sub-contractor (GC/SC)) regarding this issue. Moreover, the impact of building structural parameters on the FWS selection criteria has not been investigated. This study aims to fill this knowledge gap through analysing the FWS selection criteria for building construction projects while comparing the perspectives and perceptions of different groups of construction professionals and companies and investigating how FWS selection criteria are affected by the building structural parameters. Based on a comprehensive literature review, 35 FWS selection criteria were identified and a questionnaire was developed. The questionnaire data obtained from 222 Turkish construction professionals were statistically analysed using mean score analysis, the Kruskal–Wallis test, and the Mann–Whitney U test. According to the study’s findings, the FD/FSL group presented significant statistical differences regarding the FWS selection criteria as compared to the CO, PM/CM/SE, and PL/PR/TO groups. Moreover, the total area of building construction and total building height significantly affected the FWS selection criteria. This study serves to underscore the perspectives of various groups of construction professionals and the critical connection between the structural parameters and FWS selection criteria. The findings of this study may guide construction professionals to select the appropriate FWS for their building construction projects.
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Swarnkar, Jagriti. "Examining Seismic Response for Rigid Building Frame Having Composite Column." International Journal for Research in Applied Science and Engineering Technology 10, no. 7 (July 31, 2022): 3647–53. http://dx.doi.org/10.22214/ijraset.2022.45821.
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Abstract: Concrete filled steel tubes are generally used in Beams, Columns, Piers and caissons for deep foundations. The steel tube functions as the formwork for casting the concrete and hence, construction cost is reduced. The prime focus of the present work is to study the behavior of RCC structure under the effect of seismic loads provided with composite columns. This research study comprises of seismic analysis with the design of rigid frame with Reinforced Concrete column, Concrete encased steel and steel tube encasing concrete columns. These cases are designed based on IS 1893:2016 using ETABS software. The result shows that steel encased concrete is performing better than conventional column. The construction practices is the only difficulty arises in such of composite column.
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Song, Xiao Ruan, Pei Ge Liu, Dong Fu Zhao, Yu Ting Qu, and Xiao Yun Zhang. "Study on Stay-in-Place Cement Formwork and the Application." Advanced Materials Research 163-167 (December 2010): 952–55. http://dx.doi.org/10.4028/www.scientific.net/amr.163-167.952.
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Three contents are included in this paper: 1) Through orthogonal experiment, some principal materials and their use levels which will influence performances of cement formwork are optimized and researched. A matched group could bring best comprehensive performance plate suitable to be used as construction formwork is obtained. 2) Through study the strength retention rate of specimens after immersing in various solutions for different ages, the alkali resistance property and lasting quality of the formwork are investigated, and it indicates that during general serviceable life specified by China Structure Design Code, the failure probability due to durability is very low. 3) Through mechanical experiments of combined slabs with different conjoint methods, cooperation performance between formwork and concrete is studied, which prove composite slabs work well.
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Lee, Taegyu, Jaehyun Lee, Jinsung Kim, Hyeonggil Choi, and Dong-Eun Lee. "Effect of Formwork Removal Time Reduction on Construction Productivity Improvement by Mix Design of Early Strength Concrete." Applied Sciences 10, no. 20 (October 11, 2020): 7046. http://dx.doi.org/10.3390/app10207046.
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In this study, we examined the effects of cement fineness, SO3 content, an accelerating agent, and chemical admixtures mixed with unit weights of cement on concrete early strength using concrete mixtures. C24 (characteristic value of concrete, 24 MPa) was used in the experiment conducted. Ordinary Portland cement (OPC), high fineness and SO3 OPC (HFS_OPC), and Early Portland cement (EPC) were selected as the study materials. The unit weights of cement were set to OPC 330, 350, and 380. Further, a concrete mixture was prepared with a triethanolamine (TEA)-based chemical admixture to HFS. A raw material analysis was conducted, and the compressive strength, temperature history, and maturity (D∙h) were examined. Then, the vertical formwork removal time was evaluated according to the criterion of each country. Finally, the time required to develop concrete strength of 5 MPa was estimated. Results showed that the early strength of concrete mixed with HFS and EPC was greater than that exhibited by concrete with an increased unit weight of cement with OPC. In addition, when HFS was used with EPC, its strength developed early, similar to the trend exhibited by EPC, even at low temperatures.
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Prokhorov, Sergei. "The use of nanomodified concrete in construction of high-rise buildings." E3S Web of Conferences 33 (2018): 02065. http://dx.doi.org/10.1051/e3sconf/20183302065.
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Construction is one of the leading economy sectors. Currently, concrete is the basis of most of the structural elements, without which it is impossible to imagine the construction of a single building or facility. Their strength, reinforcement and the period of concrete lifetime are determined at the design stage, taking into account long-term operation. However, in real life, the number of impacts that affects the structural strength is pretty high. In some cases, they are random and do not have standardized values. This is especially true in the construction and exploitation of high-rise buildings and structures. Unlike the multi-storey buildings, they experience significant loads already at the stage of erection, as they support load-lifting mechanisms, formwork systems, workers, etc. The purpose of the presented article is to develop a methodology for estimating the internal fatigue of concrete structures based on changes in their electrical conductivity.
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Vervoort, P. "Lakehead terminal elevators: aspects of their engineering history." Canadian Journal of Civil Engineering 17, no. 3 (June 1, 1990): 404–12. http://dx.doi.org/10.1139/l90-044.
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Massive grain elevators have been a dominant feature of the waterfront at Thunder Bay since 1883 when the first terminal was under construction. The earliest terminal elevators built by the Canadian Pacific Railway were constructed in the wooden crib technique on a pile foundation. By the turn of the century, the inadequacies of the crib terminals forced engineers to experiment with new materials and new design concepts for terminal elevators. Steel, tile, and reinforced concrete all came into use for terminal elevator construction between 1898 and 1903. By 1910, the plan of the elevator had evolved from a single building into four separate structures. The appearance of the typical Lakehead terminal elevator today is the result of these engineering experiments which occurred at the end of the nineteenth century and in the early years of the twentieth. Key words: grain elevators, concrete construction, slip forms, formwork, bins, silos, timber construction, crib walls, cribs, steel construction.
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Jarkas, Abdulaziz M. "Buildability factors affecting formwork labour productivity of building floors." Canadian Journal of Civil Engineering 37, no. 10 (October 2010): 1383–94. http://dx.doi.org/10.1139/l10-063.
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Several factors affect labour productivity, but buildability is one of the most important. A thorough investigation of the literature, however, revealed a dearth of research into the effect of buildability on labour productivity of in situ reinforced concrete construction. Therefore, this research focuses on quantifying the effects and relative influence of the variability of beam sizes, repetition of floor layout, floor area, average slab panel area, intersection of beams, beam–floor area ratio, and percentage of curved beams and nonrectangular slab panels on formwork labour productivity of building floors. Apart from the variability of beam sizes, buildability factors investigated are found to have significant effects on formwork labour productivity, confirming the importance of applying the concepts of rationalization, standardization, and repetition to the design stage of building projects. The findings can be used to provide designers with feedback on how well their designs consider the requirements of buildability principles and the consequences of their decisions on the labour efficiency of the formwork operation. On the other hand, the depicted patterns of results may further provide guidance to construction managers for effective activity planning and efficient labour utilization.
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Caluk, Nerma, Islam M. Mantawy, and Atorod Azizinamini. "Cyclic Test of Concrete Bridge Column Utilizing Ultra-High Performance Concrete Shell." Transportation Research Record: Journal of the Transportation Research Board 2674, no. 2 (February 2020): 158–66. http://dx.doi.org/10.1177/0361198120906088.
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Ultra-high performance concrete (UHPC) is a durable material that can be used in constructing new and unique structural elements. This research utilizes UHPC to construct prefabricated shells that act as stay-in-place forms for bridge columns and eliminate the use of traditional formwork. These innovative structural elements reduce the on-site construction time, improve the structural performance of the column, and act as a protective layer in aggressive environments. Generally, during the construction process, the prefabricated UHPC shell is placed around the column reinforcement, which is fabricated using conventional methods. To connect the UHPC shell and column reinforcement with the footing and footing dowels, a step made of UHPC is utilized. The UHPC step connection is designed to shift the plastic hinge away from the column-to-footing interface. In the next stage, normal concrete is cast inside the shell, forming a concrete-filled UHPC shell. The final stage of construction involves placing and connecting a prefabricated cap-beam using the same UHPC step connection. The column specimen was tested under constant axial load and incremental lateral load. In this test, the UHPC shell cracked on the north side at a drift ratio of 3%; however, the column had a significant capacity and behaved similarly to a conventional reinforced concrete column during higher cycles of drift ratios. The test was completed after the column had reached a drift ratio of 7.5% when the first bar ruptured. No damage occurred in the footing and UHPC step which proved that the design was successful in shifting the plastic hinge away from the column-to-footing interface.
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Cheng, Shao Tsai, and I. Tsen Liu. "Construction Technology for Improving Concrete Surface Quality." Applied Mechanics and Materials 353-356 (August 2013): 2803–7. http://dx.doi.org/10.4028/www.scientific.net/amm.353-356.2803.
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The reinforced concrete is widely used in the current building system; there are several finishing-free concrete surface techniques for the time being, but the undesirable phenomena affecting flatness and smoothness, such as air voids, pores, honeycombs and cold joints on the completed surface often appear. For this study, the Vibration Degassing Machine (VDM) was created and patented which is used to conduct the second partial ramming modification on the interfaces between concrete and formworks that eliminates the air voids on concrete surface efficiently and reduces the pits after removing formworks to enhance the smoothness on concrete surface which ideally presents the beauty of original design.
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Smith, Gary R., and Awad S. Hanna. "Factors influencing formwork productivity." Canadian Journal of Civil Engineering 20, no. 1 (February 1, 1993): 144–53. http://dx.doi.org/10.1139/l93-015.
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Estimates indicate that 30 to 70 percent of cast-in-place concrete cost is attributable to the assembly and stripping of formwork. This wide percentage range is partially due to factors that are not well understood with regard to their influence on productivity. The purpose of this paper is to identify the factors that influence formwork productivity and identify a methodology to evaluate productivity data. Two groups of factors were found to have a great effect on formwork productivity: non-measurable factors such as contract document and measurable factors such as engineering design. This paper discusses the effect of both groups of factors on the productivity of vertical formwork. To quantify the effect of the measurable factors on formwork productivity, a case study of the productivity of a crew of carpenters erecting wall formwork for a three-story underground parking structure is presented and analyzed. Data were collected by physically measuring the daily output of vertical formwork erected and the total daily work hours. Key words: formwork, productivity, construction methods.
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Žiogas, Vigantas Antanas, Svajūnas Juočiūnas, Violeta Medelienė, and Giedrius Žiogas. "CONCRETING AND EARLY HARDENING PROCESSES IN MONOLITHIC REINFORCED CONCRETE STRUCTURES / PROCESAI, VYKSTANTYS BETONAVIMO IR PRADINIO KIETĖJIMO METU GELŽBETONINĖSE MONOLITINĖSE KONSTRUKCIJOSE." Engineering Structures and Technologies 4, no. 2 (June 26, 2012): 67–75. http://dx.doi.org/10.3846/2029882x.2012.699258.
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The exploitation time and reliability of monolithic reinforced concrete structures largely depend on concreting technology and process influence during concreting and early setting stages. Different types of cracks in monolithic reinforced concrete structures appear due to internal and external effects. Cracks appear when the technology of structure concreting is damaged, when formwork is removed during the further setting and structures loaded period. In order to avoid micro and macro cracks in monolithic structures, it is important to measure the particular setting time moment and technological process moment when stresses that exceed the permissible values appear in concrete. The article analyses the processes that appear when horizontal, sloping and vertical monolithic reinforced concrete structures are concreted. The analysis of concrete mixture pressure on formwork is performed. The pressure which is calculated according to different countries’ methodology is different: the smallest pressure is obtained calculating according to the British recommendations, and the largest pressure is obtained according to French CIB recommendations. In Lithuania, it is recommended to follow the German DIN 18218 standard. The balance conditions of concrete mixture concreting on slope surface are described. The main concreting technology parameters and their interaction are analysed; the speed, intensity and time of continuous concreting technology are presented. When the process of continuous concreting is performed, it is necessary to evaluate the interaction and values of parameters properly. Methodical theoretical calculation is presented. Practical solutions for industrial building construction applying the modern sliding formwork technology are presented. The impact of cement type, superplasticizers and temperature over the concrete mixture mobility, changes, fresh concrete structural strength and concrete setting kinetics are analysed. The main characteristics of the initial setting — the beginning of structure formation, when concrete mixture turns into concrete state — is analysed applying the ultrasonic method. The beginning of structure formation influences the regulated time of concrete mixture laying and compaction. The requirements for structural strength (permissible strength limits) and concreting rate (formwork movement) of freshly formed concrete are set when the construction is performed applying the continuous concreting technology method. The analysis is implemented performing the construction of cylindrical sludge tank with slipping formwork. While performing the analysis during concreting, it was stated that the concrete setting kinetics corresponds to the sludge tank concreting rate. The analysis performed after concreting and in 28 days of hardening revealed that there are no surface defects or cracks, and concrete strength exceeds the required sludge tank design strength. Santrauka Monolitinių gelžbetoninių statinių konstrukcijų eksploatacijos trukmė ir patikimumas daugiausia priklauso nuo betonavimo technologijos ir procesų poveikių betonavimo bei pradinio kietėjimo metu. Straipsnyje nagrinėjami procesai, vykstantys betonuojant horizontaliąsias, nuožulniąsias ir vertikaliąsias monolitines gelžbetonines konstrukcijas. Atlikta betono mišinio slėgio į formas analizė. Tiriami pagrindiniai betonavimo technologijos parametrai, analizuojamas jų ryšys, pateikiamas nepertraukiamo betonavimo technologijos betonavimo greitis, intensyvumas, trukmė. Atlikti teoriniai skaičiavimai ir siūlomi praktiniai sprendimai pramoninių statinių statybai, naudojant šiuolaikinę slankiųjų klojinių technologiją. Ištirta cemento tipo, superplastiklių, temperatūros įtaka šviežiai suformuoto betono struktūriniam stipriui ir betono kietėjimo kinetikai. Nustatyti reikalavimai šviežiai suformuoto betono struktūriniam stipriui, betonavimo greičiui (klojinių kėlimui), vykdant statybą nepertraukiamos betonavimo technologijos metodu. Tyrimai pritaikyti vykdant cilindrinio dumblo pūdytuvo statybą slankiaisiais klojiniais.
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Rady, Mohammed, and Sameh Youssef Mahfouz. "Effects of Concrete Grades and Column Spacings on the Optimal Design of Reinforced Concrete Buildings." Materials 15, no. 12 (June 17, 2022): 4290. http://dx.doi.org/10.3390/ma15124290.
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This paper investigates the effects of concrete grades and column spacings on the optimal design of reinforced concrete (RC) buildings. To this end, cost design optimization was performed for buildings with three different floor systems: flat plates (FS), flat slabs with drop panels (FSDP), and solid slabs (SS). The evolutionary method provided by the Excel solver was used as the optimization algorithm because it can deal with the complex nature of structural design problems. The objective function was the total construction cost of the building, including the costs of concrete, reinforcement bars, labor, and formwork, while still fulfilling the constraints of the Egyptian code of practice (ECP-18). The applicability of the presented algorithm was investigated in a design example, where the tuning of the evolutionary algorithm control parameters was sought, and the best parameters were investigated. Two case studies were employed to study the impacts of changing the column spacing and concrete grades on the optimal cost for each floor system. The results showed that low concrete grades, (i.e., characteristic strength up to 40 MPa) and column spacings up to 5 m are preferred in terms of direct construction costs for low-rise RC residential buildings.
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Advincula, Jericson H., Dustin Glenn C. Cuevas, Allan Dave A. Dela Cruz, and John Paul D. Carreon. "Structural Characterization of Foamed Composite Structural Insulated Panel with Coir for Load Bearing Wall Application." Materials Science Forum 934 (October 2018): 222–26. http://dx.doi.org/10.4028/www.scientific.net/msf.934.222.
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Permanent formwork building system is a method that uses the formwork as a contributor to the load bearing capacity of the structure. This study characterized the proposed foamed composite structural insulated panel (CSIP) with coir for load bearing wall application in low rise construction. The percentage of coir in foamed concrete that could significantly increase the compressive and flexural strength of the panel considering the effect of coir to the workability of the foamed concrete were determined. The results showed that the samples with 0.5% coir had the maximum increase in its compressive and flexural capacity and further addition of coir decreases its capacities. The results also showed that it could carry the required design loads. Moreover, using Euler’s buckling equation for the effect of slenderness, the panel could be used as exterior wall for a height of 2m, 3m, and 4m and as interior wall for a height of 2m and 3m. It can be concluded that the proposed panel could be used as a load bearing wall in low rise construction.
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Saputra, Pungky Dharma. "Identification of Precast Parapet Work Activities in Elevated Railway Construction." Applied Research on Civil Engineering and Environment (ARCEE) 2, no. 02 (February 28, 2021): 52–61. http://dx.doi.org/10.32722/arcee.v2i02.3416.
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Railway infrastructure development is very massive in Indonesia. Many projects have been constructing since 2013, such as the Mass Rapid Transit (MRT), Light Rail Transit (LRT), Double-Double Track (DDT), and High-Speed Rail (HSR). And all of these projects were design with elevated structures. When applying precast parapet panel technology in the MRT project elevated section, the contractor didn’t have a reference for precast parapet work activities. Hence, it required new planning for its construction and took time. The project sample of this research was MRT Jakarta CP 103 Project. There were three stages in this research starting from documentation analysis, expert judgment, and respondent survey. There were 5 bridge construction experts and 30 respondents which were professional engineers asked for their recommendations and opinions. Descriptive analysis was applied to know the percentage of opinions. This research focuses on identifying precast parapet activities in elevated railway construction project. There are 14 activities that had been identified in this research, namely preparation, position survey, adjustment material installation, precast parapet panel shifting from trailer to the top of deck slab, precast parapet panel distribution, precast parapet panel installation, rebar parapet installation for concrete stitch, sealing work, concrete casting, formwork dismantling, and finishing. These activities will be very useful for similar precast parapet works in a future project.
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Cazacu, Nicolae, Aurelia Bradu, and Nicolae Florea. "Self Compacting Concrete Structures: A Techno-Economic Analysis." Advanced Engineering Forum 21 (March 2017): 624–31. http://dx.doi.org/10.4028/www.scientific.net/aef.21.624.
Full textAbstract:
The concept of self-compacting concrete (SCC) was performed in late 1980 by Japanese researchers as a solution for the lack of skilled workers and decreasing quality in building industry. The high fluidity of SCC allows flowing under its own weight, filling completely the formwork without any vibration or material segregation, providing a higher quality of the concrete surface. Since its discovery, a large number of researcher studied its rheological properties, adjusted mix design methods and analysed mechanical characteristics. The placement method for conventionally concrete is no more valid for SCC, as mixture behaviour changed substantially. This aspect was less examined and the published material is inconsistent, even though it plays an essential role in the assessment of the global cost of a building. The aim of this study is to investigate materials cost, the labour requirements, formwork demands, methods of placement and construction time for building a structure using SCC and vibrated concrete and compare the results.
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Terzioglu, Taylan, Gul Polat, and Harun Turkoglu. "Formwork System Selection Criteria for Building Construction Projects: A Structural Equation Modelling Approach." Buildings 12, no. 2 (February 11, 2022): 204. http://dx.doi.org/10.3390/buildings12020204.
Full textAbstract:
Selecting the appropriate formwork system (FWS) is a critical aspect in the successful completion of reinforced concrete (RC) building construction projects. The selected FWS has a significant impact on the cost, time, and quality performances of the project. As there are many FWSs and formwork fabricators (FWFs) available, the selection of the FWS depends on several compromising and conflicting criteria. This study aims to identify the FWS selection criteria groupings (e.g., latent factors) and investigate the quantitative interrelationships among them. For this purpose, 35 FWS selection criteria were identified through literature review, and a questionnaire was developed. The data from the questionnaire were statistically analyzed, and five latent factors were identified: FWS-FWF characteristics, structural design, local conditions, cost, and performance indicators. A conceptual framework was developed based on the latent factors, and a structural equation modelling (SEM) approach was utilized to identify the effects among the latent factors. The results of the SEM approach confirmed that FWS-FWF characteristics are affected by the structural design and local conditions and FWS-FWF characteristics have a substantial effect on cost and the performance indicators of the project. The findings of this study may assist construction professionals in selecting the FWS in building construction projects.