• Geomechanics and Engineering
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• v.15 no.3
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• pp.911-917
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• 2018

This paper concerns a numerical investigation on the effect of construction sequence on three-arch (3-Arch) tunnel behavior. A three-arch tunnel section adopted in a railway tunnel construction site was considered in this study. A calibrated 3D finite element model was used to conduct a parametric study on a variety of construction scenarios. The results of analyses were examined in terms of tunnel and ground surface settlements, shotcrete lining stresses, loads and stresses developed in center column in relation to the tunnel construction sequence. In particular, the effect of the side tunnel construction sequence on the structural performance of the center structure was fully examined. The results indicated that the load, thus stress, in the center structure can be smaller when excavating two side tunnels from opposite direction than excavating in the same direction. Also revealed was that no face lagging distance between the two side tunnels impose less ground load to the center structure. Fundamental governing mechanism of three-arch tunnel behavior is also discussed based on the results.

• Journal of the Korea Institute of Building Construction
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• v.6 no.4 s.22
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• pp.77-83
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• 2006

The purpose of this study is to measure the straightness of prefounded columns during underground construction stages. There are several causes of an error of prefounded column: (1) columns connected by welding or bolting, (2) by placement of concrete and aggregates around columns, (3) movement during construction, and (4) load applied during construction. The error of column straightness is different for each column, and the tilting of columns is shown in one or two directions between floors. The additional loads caused by the error of straightness may give damage to buildings. This paper presents the measurement results of column straightness, and thus providing a basis for further analysis.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.11a
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• pp.44-45
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• 2019

Tower cranes are essential equipments that play a key role in the overall process of large-scale construction projects, as well as high-rise apartments construction projects. Tower cranes hoist various loads near and over people, working in crowded environments, sometimes in overlapping work areas, and often under the constraints of time, budget, and labor. This work system further increases the safety risks of sites with inherently hazardous workplaces. The methodology of this research was based on a comprehensive inquiry of a team of experts, including safety managers and equipment managers of major construction companies and previous literature search. Due to the limited resources available to improve safety and prevent accidents, more attention should be paid to all parties involved in factors that have been evaluated to have a significant impact on site safety due to tower crane operations.

• Journal of the Korean Geosynthetics Society
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• v.23 no.3
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• pp.23-30
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• 2024

According to the method of settling the construction structure on the ground to keep the structure safe, the ground anchor method is divided into a load-distributing anchor and a general anchor. Recently, the application of load-distributed anchors, which show a large degree of recognition by anchors, is increasing in the field, but the problem of field applicability is also caused. The load-distributed anchor fixes the tensile force to each section of the lecture line and applies it, causing a problem of asymmetric loads in which the maximum tensile force size of each settlement site differs due to the length difference of the anchor body. Therefore, in this study, as a quality management method according to the asymmetric load of anchors, a mono-type load cell that can measure the load for each lecture line of a load-distributed anchor was developed, and the field applicability was analyzed by comparing and analyzing the measurement results of the existing multi-type load cell and mono-type load cell. As a result of the study, the multi-type load cell had no choice but to estimate the working load for each inner body, so it was impossible for the load-distributed anchor to manage it according to the generation of asymmetric loads for each lecture line. However, in the case of a mono-type load cell the load was measured for each inner body and for each lecture line, regardless of ground conditions and construction conditions, and thus the load value was measured for each lecture line, enabling safety management and construction management according to the occurrence of asymmetric loads.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.451-454
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• 2002

In the present paper, the practicability of Commentray on Wind Loads of Korean Standard Design Loads fur Buildings, which has been enacted in Minstry of Construction and Transportation in June 2000, is validated by using the meteorological data measured at Homi-Cape, Pohang. Assuming that the vertical wind profile follows the power-law in a quasi-steady state, wind profile exponents are calculated by seasons by using wind data as collected through four monitoring towers. According to the Commentray on Wind Loads, Pohang is classified with its exposure category being B and the wind profile exponent being 0.22, while it is identified that the average wind profile exponent as calculated in this study is 0.26. Also, in this paper, a cross-correlation method is suggested in order to identify any meteorological correlation between measurement sites quantitatively.

• Computers and Concrete
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• v.14 no.1
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• pp.41-57
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• 2014

Modern trend in structural design is to use smaller elements in order to ensure several purposes such as economy, functionality and aesthetic in appearance. However, because of decreasing rigidity of the structural elements, the system displacements increases and displacements become an important subject in this kind of structures takes into account both geometrical changes and the carrying capacity of the material after linear-elastic boundary. In this study, a method is proposed to calculate the failure loads and to analyse the reinforced concrete space frame systems. The numerical examples gathered from the literature survey are solved with this method utilising the prepared computer program and the comparable results are presented. The results show that the method is sufficiently accurate.

• Interaction and multiscale mechanics
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• v.1 no.3
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• pp.381-396
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• 2008

The aerostatic instability of cable-supported bridges is studied, with emphasis placed on modeling of the geometric nonlinear effects of various components of cable-supported bridges. Two-node catenary cable elements, which are more rational than truss elements, are adopted for simulating cables with large or small sags. Aerostatic loads are expressed in terms of the mean drag, lift and pitching moment coefficients. The geometric nonlinear analysis is performed with the dead loads and wind loads applied in two stages. The critical wind velocity for aerostatic instability is obtained as the condition when the pitching angle of the bridge deck becomes unbounded. Unlike those existing in the literature, each intermediate step of the incremental-iterative procedure is clearly given and interpreted. As such, the solutions obtained for the bridges are believed to be more rational than existing ones. Comparisons and discussions are given for the examples studied.

• Journal of Korean Tunnelling and Underground Space Association
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• v.6 no.1
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• pp.17-23
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• 2004

Prediction of lining loads is one of the key issues to be addressed in the design of a tunnel. The validity of the existing design methods is reviewed by comparing the loads calculated using the methods with the field measurements obtained from several tunnels in Edmonton, carada. However, the existing methods are determined not to be fully satisfactory for the prediction of primary lining loads. To account for the stress reduction occurring prior to lining installation, the stress reduction factor is used coupled with an analytical solution for calculation of lining loads. Typical values of dimensionless load factors nD/H for tunnels in Edmonton are obtained from parametric analyses and presented in a table. The loads calculated using the proposed method are compared with field measurements collected from tunnels in Edmonton to verify the method. The method can be used for other tunnels if the tunnels are built in stiff or dense soils, where good ground control is accomplished during the tunnel construction.

• IE interfaces
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• v.17 no.2
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• pp.142-148
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• 2004

The objective of bridge construction cost allocation is to distribute in a fair and rational manner the bridge construction costs among those vehicles using the bridge. In most bridge construction cost allocation studies, bridge construction costs are mainly distributed according to traffic load(gross vehicle weight), without any consideration of bridge capacity requirements(the number of lanes). In this paper, a bridge cost allocation method for considering both traffic capacity and traffic loads is developed. The proposed method is based on cooperative game theory, particularly two concepts known as the Aumann-Shapley (A-S) value and Shapley value. This method can help to analyze the impact of traffic capacity costs. By applying the proposed method to an example, traffic capacity cost is found to be high so that traffic capacity should be considered to allocate the bridge construction costs to vehicle classes in a more equitable manner.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2008.05a
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• pp.43-46
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• 2008

In Top-Down construction for underground structures, the placement of slab as a horizontal supporting member against lateral earth pressure is an important process in determining construction time and cost. Usually, a reinforced concrete perimeter girder distributes concentrated lateral loads from earth retaining structures such as Cast-in-place (CIP) piles. By combining the function of the R/C perimeter girder and horizontal slabs, the Opened Slab Method is efficient for reducing construction time by elimination of time-consuming formwork for traditional perimeter girders. The structural performance of the method is also discussed in this paper.