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Abstract

Nowadays, self-climbing formworks are commonly used in the construction of concrete buildings with a great height, such as high-rise buildings, silos, and bridge piers. A regular formwork can be improved to have more functions, e.g., the formwork itself can climb to the desired construction site. Climbing characteristics of the formwork as well as opening and closing characteristics of the formwork shell are essential criteria for evaluating the performance of a self-climbing formwork. The effective ones were mentioned in different studies, where most of them were published in patents of countries, e.g., the United States and China. Dissimilar from these studies, this paper presents several improvements for some certain groups to enhance the features of a hydraulic self-climbing formwork. Based on the analysis of the composition and the working principle of the actual climbing formwork types, a new opening and closing method of the formwork shells and a new rail clamping device are suggested. They are applied to design a self-climbing formwork with the shell’s working size of 4 m x 3 m. Their load capacity, as well as the flatness of the concrete surface after casting, are assessed. The proposed solutions can result in various advantages, e.g., the shorter initial alignment time, the increase of the quality concrete surface, and the maximal automation for construction operations.

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Bibliography

[1] Doka GmbH. https://www.doka.com/en/references/asia/burjkhalifa, 2018.
[2] Task Group 10.2, Formwork and falsework for heavy construction. International Federation for Structural Concrete (fib), Lausanne, Switzerland, 2009.
[3] C.A. Graubner, E. Boska, C. Motzko, T. Proske, and F. Dehn. Formwork pressure induced by highly flowable concretes – design approach and transfer into practice. Structural Concrete, 13:51–60, 2012. doi: 10.1002/suco.201100012.
[4] I. Puente, A. Santilli, and A. Lopez. Lateral pressure over formwork on large dimension concrete blocks. Engineering Structures, 32(1):195–206, 2010. doi: 10.1016/j.engstruct.2009.09.006.
[5] M. Arslan, O. Simsek, and S. Subasi. Effects of formwork surface materials on concrete lateral pressure. Construction and Building Materials, 19(4):319–325, 2005. doi: 10.1016/j.conbuildmat.2004.07.007.
[6] M.R. Kannan and M.H. Santhi. Constructability assessment of climbing formwork systems using building information modeling. Procedia Engineering, 64:1129–1138, 2013. doi: 10.1016/j.proeng.2013.09.191.
[7] X. Liu, Y. Hu, D. Chen, and L. Wang. Safety control of hydraulic self-climbing formwork in south tower construction of Taizhou Bridge. Procedia Engineering, 45:248–252, 2012. doi: 10.1016/j.proeng.2012.08.152.
[8] J.P. Li, J. Ruan, P. Tan, and X.J. 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, 540:201–204, 2014. doi: 10.4028/www.scientific.net/AMM.540.201.
[9] S. Hu and J. Li. Analysis of dynamic characteristics of climbing formwork under wind loads. E3S Web of Conferences 79:01016, 2019. doi: 10.1051/e3sconf/20197901016.
[10] T.J. Waldschmitt and R. Pauley. Wall climbing form hoist. Patent No. US 6557817 B2, 2003.
[11] A. Schwoerer. Method for implementing a rail-guided self-climbing formwork system with climbing rail extension pieces. Patent No. US8673189B2, 2014.
[12] M. Jentsch. Adjustable formwork climber. Patent No. US 2013/0020732 A1, 2013.
[13] FEM 1.001, Rules for the Design of Hoisting Appliances. European Material Handling Federation, 1998.
[14] BS EN 12811-1:2003, Temporary works equipment – Part 1: Scaffolds – Performance requirements and general design. British Standard, 2003.
[15] DIN 18202:2013-04, Toleranzen im Hochbau – Bauwerke, Normenausschuss Bauwesen im DIN. Germany, 2013.
[16] ACI 117M-10, Specification for Tolerances for Concrete Construction and Materials and Commentary. ACI Committee 117, USA, 2010.
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Authors and Affiliations

Van Tinh Nguyen
1
Kiem Anh Nguyen
1
Van Linh Nguyen
2

  1. Faculty of Construction Mechanical Engineering, National University of Civil Engineering, Hanoi, Vietnam.
  2. Lilama 69-1 JSC, Bac Ninh, Vietnam.
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Abstract

Materials play an important role in determining the quality and cost of a building, especially in the context of Vietnam’s rapid urbanization today. This study aims to analyze the status quo for supplier selection for construction projects in a developing country, Vietnam. Questionnaires are designed to conduct a survey among several contractors to assess the current situation of how Vietnamese construction enterprises select their material suppliers. Senior managers, project managers, site commanders, site engineers, foreman, office staff of contractors were interviewed. Based on result analysis of 117 valid responses, the most important criteria to consider when selecting material suppliers have been identified, with the most influential ones being price, delivery time, and material quality. However, the supply of materials still reveals some constraints that must be overcome. Vietnamese construction firms should pay more attention to supplier selection to optimize material delivery efficiency. This research contributes to the understanding of the status quo for supplier selection for construction projects in a developing country. This means contractors can adopt suitable measures to select material suppliers for construction projects.
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Authors and Affiliations

Nguyen Quoc Toan
1
ORCID: ORCID
Hanh Nguyen Thi My
1
ORCID: ORCID
Nguyen Van Tam
1
ORCID: ORCID
Pham Xuan Anh
1
ORCID: ORCID
Dinh Tuan Hai
2
ORCID: ORCID
Nguyen Thi Thuy
1
ORCID: ORCID

  1. Hanoi University of Civil Engineering, Faculty of Construction Economics and Management, No. 55 Giai Phong Street, Hai Ba Trung District, Hanoi, Vietnam
  2. Hanoi Architectural University, Faculty of Civil Engineering, Km 10, Nguyen Trai Street, Thanh Xuan District, Hanoi City, Vietnam
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Abstract

The main objective of this study was to assess the environmental impact of the subsurface geological structure in Nam Son landfill by hydrogeophysical method. The Electrical Resistivity Tomography (ERT), Self- -Potential (SP) and Very Low Frequency (VLF) method was used for geological structure investigation. Three profiles (total 900 m long) of two-dimensional ERT, VLF density sections and 180 SP data points scattered within the study area near the disposal site were implemented. Surface water and groundwater samples were collected from 10 sites in the area for hydrochemical analysis. Interpretations of geophysical data show a low resistivity zone (<15 Ω m), which appears to be a fully saturated zone with leachate from an open dumpsite. There is a good correlation between the geophysical investigations and the results of hydrochemical analysis.
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Authors and Affiliations

Nguyen Van Giang
Nguyen Trong Vu
Nguyen Ba Duan
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Abstract

Qualitative and quantitative results of high terrain elevation effect on spectral radiance of optical satellite image which affect the accuracy in retrieving of land surface cover changes is given. The paper includes two main parts: correction model of spectral radiance of satellite image affected by high terrain elevation and assessment of impacts and variation of land cover changes before and after correcting influence of high terrain elevation to the spectral radiance of the image. Study has been carried out with SPOT 5 in Hoa Binh mountain area of two periods: 2007 and 2010. Results showed that appropriate correction model is the Meyer’s one. The impacts of correction spectral radiance to 7 classes of classified images fluctuate from 15% to 400%. The varying changes before and after correction of image radiation fluctuate over 7 classes from 5% to 100%.
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Authors and Affiliations

Luong Chinh Ke
Tran Ngoc Tuong
Nguyen Van Hung

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