• International Journal of High-Rise Buildings
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• v.6 no.1
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• pp.83-89
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• 2017

Due to the time-dependent properties of materials, structures, and loads, accurate time-dependent effects analysis and precise construction controls are very significant for rational analysis and design and saving project cost. Elevation control is an important part of the time-dependent construction control in supertall structures. Since supertall structures have numerous floors, heavy loads, long construction times, demanding processes, and are typically located in the soft coastal soil areas, both the time-dependent features of superstructure and settlement are very obvious. By using the time-dependent coupling effect analysis method, this paper compares Shanghai Tower's vertical deformation calculation and elevation control scheme, considering foundation differential settlement. The results show that the foundation differential settlement cannot be ignored in vertical deformation calculations and elevation control for supertall structures. The impact of foundation differential settlement for elevation compensation and pre-adjustment length can be divided into direct and indirect effects. Meanwhile, in the engineering practice of elevation control for supertall structures, it is recommended to adopt the multi-level elevation control method with relative elevation control and design elevation control, without considering the overall settlement in the construction process.

• Journal of Korean Society on Water Environment
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• v.25 no.1
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• pp.125-135
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• 2009

Reliable long-term flows by SWAT-K model were applied to the relationship between stream flow and pollutant load derived from 8-day measured data of Ministry of Environment (MOE) in order to obtain continuous loadograph and evaluate accuracy in water quality modeling for the Chungju dam watershed. The measured flow were compared with flow duration curve from the model, and it showed that measured values corresponded to the almost full range of stream flow conditions except at Odae A. And there was significant relationship ($R^2=0.60{\sim}0.97$) between measured flow and water quality load at all unit-watersheds. Applying this relationship to simulated flows, continuous loadograph was obtained and compared with modeled pollutant loads. Although there were some differences during some dry and flood seasons, those were not significant and overall trend showed a good agreement. From the results, we would be able to derive a continuous loadograph based on measured data at total maximum daily loads (TMDLs) unit-watersheds on a national scale, in which stream flow and water quality have been measured at 8-day intervals since 2004, and this could be helpful to utilize distributed water quality models with difficulty in calibrating and validating parameters from lack of measured data at present.

• Journal of Ocean Engineering and Technology
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• v.23 no.1
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• pp.104-108
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• 2009

As the demands of ocean resource development increase, many offshore structures are required. To cope with the active ocean developments, many types of construction methods have been applied for offshore facilities, including oil, gas and harbors. One of the challenges is to transport and install the heave bridge caisson. Several construction methods are well understood. However, for the sake of safety and reliability, the F/D installation method can be utilized. While the caisson is carried by an F/D, the mooring force of the tug boat and the structure stability from exiting motions in the dock should be checked against external loadings and sea conditions. The external loads can be classified with wind force, current force, and wave force. In the stability analysis, transportation velocity and draft of F/D are important factors. The dynamic stability and hook load for crane barge installation for the same caisson are also studied. Considering external loads and dominant factors, the stability of caisson during transportation has been investigated.

• Journal of Korean Tunnelling and Underground Space Association
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• v.9 no.1
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• pp.91-97
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• 2007

Loads on the pillar and ground deformation in 2-arch tunnel, which is excavated in the rock mass with regular discontinuities, depending on the dips of discontinuities and the construction sequences were experimentally studied. Large scale model tests in the biaxial test facility were performed. Tested model (width 3.3m, height 3.0m, and length 0.45m) for 2-arch tunnel in 1/10 scale were built with various dips. Test results show that discontinuities have greate affects on the behavior of the 2-arch tunnel, especially on the pillar loads and ground deformation.

• Journal of Korean Society of Steel Construction
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• v.9 no.4 s.33
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• pp.611-623
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• 1997

This paper provides the results of an experimental and analytical study performed on the beam to Concrete Filled Circular Steel Column connections with the external stiffener rings under the gravity loads. Specimens are modeled as a 1/4 scale of the beam-columns as gravity loads are applied to a multi-story frame. Important parameters in this study are the width of the external rings, the diameter-thickness ratios of column and whether or not the external rings are welded to the circular column. A total of 20 specimens are tested to clarify the structural behavior of the CFT column connections with the external stiffener rings. The test results are summarized for the yield and maximum strength and stiffness. The existing design equations for the allowable and yield load capacities are referred to verify the structural characteristics for the connections.

• Journal of Korean Society on Water Environment
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• v.24 no.4
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• pp.465-472
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• 2008

Soil and Water Assessment Tool (SWAT) model was selected as a tool for assessing the effect of pollutant sources on the total loads from the Chungju Dam upstream watershed. The model was constructed through calibration of parameters related to nitrogen (N) and phosphorus (P), which was based on the runoff and sediment modeling performed in the previous research. Using this, the spatial and temporal pollutant loadings by source type were investigated. Results of this study indicated that in most forested upstream sub-watersheds, pollutant loadings from point sources were very low, and total loadings by point and non-point sources were also insignificant. On the other hand, in #14 sub-watershed including Jecheon city, the loadings by point source were relatively considerable. For the whole watershed, non-point sources accounted for 99% of sediment, 97% of N, and 93% of P loads. And monthly non-point source loadings were concentrated on rainy summer season, while point source loadings of N and P kept nearly constant throughout the year and were high on dry winter season relative to non-point source.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.730-731
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• 2015

This study aims at giving the framework to estimate the environmental load at planning and schematic phase. With increasing awareness of environmental issues, the effort to reduce the environmental impacts caused by human activity has been increasingly enlarged. So far most of researches estimating CO₂ emissions have analyzed energy consumption based on BOQ (Bills of Quantity) acquired after detailed design. There is also lack of reliability in the estimated environmental impact using the basic unit of a facility at the planning stage, because it uses a limited specific section of historical data. Thus, this study is targeted at developing framework to assess reliable environmental loads based on information available at project early phases by making case-bases from historical design information on PSC Beam Bridge. Historical database is built on the basis of the LCA (Life Cycle Assessment) and in order to set input information for estimating model, the literature about information in an early project phase are reviewed. Using the information available in the planning and schematic design stage, the Framework is presented to estimate the environmental load in an early stage in the project. Developing an environmental load estimation model in accordance with the Framework presented in this study, it is expected that the environmental load in the initial project phase can be estimated more quickly and accurately.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.37 no.4
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• pp.243-250
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• 2024

Recently, accidents involving structural elements, formwork, and shore have occurred continuously during concrete pouring, especially in multistory-shored RC structure systems with non-typical stories with increased slab thicknesses. In previous studies, an analysis was conducted on the stiffness of concrete and distribution of slab construction loads when some slab thicknesses were increased under the same conditions. This study analyzed the construction load, construction damage parameter, and shoring force by varying the construction conditions, such as the construction period and number of shores, as well as the design conditions, such as the thickness increment and number of thickness increment slabs, in a multistory-shored RC structure system with non-typical stories with increased slab thickness.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.843-846
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• 2008

Rationality of strength models for structural concrete depends on how to treat loads on boundaries and load paths within members. Differentiation between strut-and-tie models and stress fields approaches for shear strength models is discussed in this paper for salient use of current design formula in design code provisions. How to model configuration of loads and stress states along the boundary for the regions under provides a key to realistic construction of stress fields together with STM.

• Journal of the Korean Professional Engineers Association
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• v.44 no.5
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• pp.36-41
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• 2011

Design of blast resistant structures (protective structures) require the adequate design and construction practices as well as the knowledge of characteristics of the blast loads, behavior of structures and their components under these loads. This paper focuses on how to design and evaluate the structures for blast resistance, and provides principles and discussion on analysis and design capability in protective technology and recommendations.