• Journal of the Korea Institute of Building Construction
• /
• v.11 no.5
• /
• pp.523-529
• /
• 2011

In a tall building construction with reinforced concrete structures, the selection of an appropriate formwork system is a crucial factor for the success of the project. Thus, selecting an appropriate formwork system affects the entire construction duration and cost, as well as subsequent construction activities. However, in practice, the selection of an appropriate formwork system has depended mainly on the intuitive and subjective opinion of working level employees with restricted experience. Therefore, in this study, a formwork system selection model using the Adaboost algorithm is proposed to support the selection of a formwork system that is suitable for the construction site conditions. To validate the applicability of the proposed model, the selection models Adaboost and ANN were both applied to actual case data of tall building construction in Korea. The Adaboost model showed slightly better accuracy than that of the ANN model. The Adaboost model can assist engineers to determine the appropriate formwork system at the inception of future projects.

• International conference on construction engineering and project management
• /
• 2009.05a
• /
• pp.788-793
• /
• 2009

Constructing substructures by using Top-Down or Downward method needs an efficient formwork system because of difficulties in supporting concrete slabs from the bottom while excavation is in process. Existing underground formwork systems can be classified by three types: graded ground supported type (Slab On Grade, Beam On Grade), suspension type (Non Supporting Top Down Method), and bracket supported type (Bracket Supported R/C Downward). Each method has its own advantages and limits. Application of a specific formwork system for a given construction site is determined by various conditions and affect construction time and cost. This paper presents a newly developed underground non-supporting formwork system, which combines the advantages of a suspension type and a bracket supported type while it overcomes limits of two types. The developed system has a moving formwork which is supported by suspension cables hanging from the bracket placed at the top of pre-installed substructure columns. Then, the moving formwork is repeatedly lowered down for the next floor below to support concrete slab during curing. The details of this bracket and cable supported system have been investigated for the improvement of easiness in construction.

• Journal of the Korean Society of Safety
• /
• v.26 no.3
• /
• pp.59-62
• /
• 2011

Among the accidents and failures that occur during concrete construction, many are formwork failures which usually happen when concrete is being placed. A system of formwork filled with wet concrete has its weight at the top and is not basically a stable structure. Slab formwork consists of sheathing, stringer, hanger and shore. There are several types of adjustable shores. In construction site, pipe supports are usually used as a shore of slab formwork. In this study, pipe support systems with/without horizontal connector were measured by buckling test. Buckling load of respective pipe support system was analyzed by structural analysis program(MIDAS). Buckling load of pipe support with/without horizontal connector was got by test and structural analysis. According to these results, we know that horizontal connector made pipe support system very safe. Buckling load of pipe support with horizontal connector is 56% higher than that without horizontal connector. So horizontal connector is important in slab formwork systems. Finally, the present study results will be used to design slab formwork system safely in the construction sites.

• Journal of the Architectural Institute of Korea Structure & Construction
• /
• v.35 no.7
• /
• pp.171-178
• /
• 2019

Auto Climbing Formwork System (ACS) for construction of high-rise building is a construction method for automatically lifting the formwork system supported by the anchor on the pre-constructed concrete wall. It has excellent construction speed and quality, but it has the possibility of structural failure depending on the quality of concrete and also has low economical efficiency due to the use of foreign technology. In order to overcome these problems, this study conducted an optimum design for the development of a new concept of Corner Supported Auto Climbing System (CS-ACS) in conjunction with the development of corner steel-reinforced concrete core wall system. For the design the formwork system, the basic module and structural member compositions were planned, and the structural analysis program was used to analyze the optimum member's cross section and spacing. As a result, the horizontal displacement and the stress of the horizontal members were influenced by the spacing more than the cross-section of the member. On the other hand, vertical members did not affect the displacement and stress of the formwork system. The form tie was very effective in controlling the displacement when adjusting the spacing of the horizontal members, but when the spacing of the form tie is more than 1,500mm, it is analyzed that form tie is yielding in basic module. When the span of the formwork system is more than 30m, it is analyzed that the basic module needs to be changed because of the increase of overall displacement.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2005.11a
• /
• pp.111-116
• /
• 2005

The formwork is very important in terms of time and cost of construction project. There have been ample research efforts regarding to technical issues such as types, specifications, and productivities. However, no previous research has addressed managerial requirements of the formwork. Thus, this paper investigated the present status of form work analyzing a case-study company, and derived an improvement plan for the formwork. The findings includes 1) the needs for increasing use of system forms in order to improve the quality and the safety and 2) further development of management system of formwork in order to enhance the efficiency.

• Steel and Composite Structures
• /
• v.21 no.5
• /
• pp.1105-1119
• /
• 2016

In this study, it is presented that a new developed approach for equivalent area-distributed loading (EADL) induced from a single concentrated force. For the purpose, a full scale 3D steel formwork system was constructed in laboratory conditions. A developed load transmission platform was put on the formwork system and loaded step by step on the mass center. After each load increment, displacement was measured in several crictical points of the system. The developed platform which was put in to slab of formwork to equivalently distribute the load from a point to the whole slab was constituted using I profiles. A 3D finite element model of the formwork system was analyzed to compare numerical displacement results with experimental ones. In experimental tests,difference among the displacements obtained from reference numerical model (model applied EADL) and main numerical model (model applied single load using a load cell via load transmission platform) is about %13 in avarage. Difference among the displacements obtained from experimental results and main numerical model under 30 kN single load is about %11 in avarage. The results revealed that the displacements obtained experimentally and numerically are dramatically closed to each other. It is highlighted from the study that the developed approach is reliable and useful to get EDL.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2006.05a
• /
• pp.622-625
• /
• 2006

This Study is the consideration for new formwork assembly method in Bearing Wall System. It is consisted of two parts. one is researched into an ordinary formwork system and suggested a new formwork system. The other makes an investigation into the resisting capacity of proposed method by experimental and field test. For the application of this method to the field, it is expected to improve workability and safety, and to reduce the loss of labor.

• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 1998.10a
• /
• pp.142-145
• /
• 1998

The purpose of this study is to estimate lateral formwork pressure controlled by super-workable fresh concrete using prototype structrues such as, tall wall, retaining wall, and beam quantitativly. As a result of this experiment, a function which can be used to design a formwork system and to predict formwork pressure curve is formulated.

• Proceedings of the Korea Concrete Institute Conference
• /
• 1996.10a
• /
• pp.295-300
• /
• 1996

The design of formwork system for vertical form faces is controlled by pressures predicted to act against the formwork by fresh concrete. An overestimation of pressure results in heavy, and ex-pensive formwork. An underestimation results in malformed structure, of in some cases, it causes the failure of the formwork. This study is a preliminary step in determination lateral pressures with High folwable concrete. To estimate lateral formwork pressures, we measured tensile strain of formtie in the movable part of the form. From the experimental results maximum lateral pressure and the location at which maximum pressures occurs, were determined. The experimental results are compared with the results predicted by the Gardner & Qureshi's proposed equation and the accepted Korean Standard Specification for concrete and ACI equation.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2014.11a
• /
• pp.205-206
• /
• 2014

It is very important to reduce the construction duration of the Reactor Containment Building (RCB) when considering the more than 50 months on average from concrete placement to completion. The purpose of this study attempts to evaluate the single-stage workability of the system given a change in the height of the setting of RCB exterior wall formwork to be used in nuclear power plant construction. As a result of this study, it is possible height of 3.5m~4m uses formwork when analyzing the construction period and material costs an increase in formwork by concrete lateral pressure, to ensure the workability of the RCB exterior wall formwork. Through this study, I want to provide as basic data for the improvement of workability and RCB shortening the construction period.