• Journal of Korean Association for Spatial Structures
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• v.18 no.1
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• pp.85-92
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• 2018

Construction techniques and materials are developing and structures are designed to be irregular shaped, and therefore more detailed structural analysis is required. The purpose of this study is to analyze the cause of accidents related to falsework systems during construction and discuss prevention methods in order to prevent accidents relate to prefabricated shoring system during construction. In this paper structural analysis was conducted to study the influence of slab irregularity on system supports and analysis to investigate the participation of the bracing in the system support.

• Computers and Concrete
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• v.20 no.6
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• pp.689-704
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• 2017

The paper presents experimental and numerical investigations of prefabricated composite structural building reinforced concrete slabs with the insulating material for a residential building construction. The building slabs were composed of concrete and expanded polystyrene. In experiments, the slabs in the full-scale 1:1 were subjected to vertical concentrated loads and failed along a diagonal shear crack. The experiments were numerically evaluated using the finite element method based on two different constitutive continuum models for concrete. First, an elasto-plastic model with the Drucker-Prager criterion defined in compression and with the Rankine criterion defined in tension was used. Second, a coupled elasto-plastic-damage formulation based on the strain equivalence hypothesis was used. In order to describe strain localization in concrete, both models were enhanced in the softening regime by a characteristic length of micro-structure by means of a non-local theory. Attention was paid to the formation of critical diagonal shear crack which was a failure precursor.

• Structural Engineering and Mechanics
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• v.82 no.6
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• pp.801-812
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• 2022

To better promote the development of fabricated buildings, this paper studies the seismic behavior of precast concrete beam-column bolted joint under vertical low cyclic loading. The experimental results show that cracks appear in the beam-column joint core area. Meanwhile, the concrete and the grade 5.6 bolts are damaged and deformed, respectively. Specifically, the overall structure of the beam-column joint remains intact, and the bolts have good energy dissipation capacity. Based on the experimental study, a new method of beam-column bolted connection is proposed in simulation analysis. The simulation results show that the bolts deform in the core area of the new beam-column joint, which enhances the concrete shear capacity legitimately and protects the T-end of the beam against shear failure. To summarize, both the experimental joint and the simulated joint prolong the service life by replacing the bolts under the seismic loading. The research results provide a reference for applications of the fabricated beam-column joint.

• Journal of the Korean Institute of Rural Architecture
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• v.15 no.3
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• pp.17-24
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• 2013

This study examined and investigated architectural characteristics such as the use of buildings, the number of layers, and structure, and roof landscape characteristics such as roof types, materials, and color in rural villages which were located on the street on the assumption that the landscape of rural villages should be managed by considering visual aspects. The results were as follows. The commonest frequency was found in 'residence'(2/3) for the use of buildings and 'masonry structure'(2/3) for the structure. 'Wood structure' and 'light gauge steel structure(prefabricated structure)' were also commonly found. The results suggest that although many rural houses have partially improved by agricultural and fishery development projects and garden suburbs has been increased by city residents' desire for rural life, there have been still many old houses. Frequently used roof types were a gambrel roof and a hipped roof. Roof materials were mixed in several materials such as tiles, slate, panels, color steel plate, reinforced concrete, and asphalt shingles. Roof color was also mixed in several colors such as reddish N7 and N0.5 of Neutral color, 10R3/6 and 10R3/10 of R color, 7.5B4/10 and 7.5B7/8 of B color and 5G8/6 of G color. The result suggests that roof color impedes the landscape of rural villages on the street. Based on the results, some roofs of rural villages were improved by the support of the government or the local governments but there are still many old roofs. The mixture of improved roofs and old roofs mainly contributed to impeding the landscape of rural villages and it was probably caused by the lack of systematic landscape plans by individual improvement of buildings. Therefore, it is necessary to devise systematic landscape plans in consideration of local identity and neighboring environment. In particular, the guideline for roof color influencing a street landscape should be established.

• Structural Engineering and Mechanics
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• v.70 no.6
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• pp.765-779
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• 2019

Most of the existing evaluation criteria of vibration serviceability rely on the peak acceleration of the structure rather than that of the people keeping their own body unmoved on the structure who is the real receiver of structural vibrations. In order to accurately assess the vibration serviceability, therefore, a full path assessment approach of vibration serviceability based on vibration source, path and receiver is not only tentatively proposed in this paper, taking the peak acceleration of receiver into account, but also introduce a probability procedure to provide more instructive information instead of a single value. In fact, semi-rigid supported on both sides of the structure is more consistent with the actual situation than simply supported or clamped due to the application of the prefabricated footbridge structures. So, the footbridge is regarded as a beam with semi-rigid supported on both sides in this paper. The differential quadrature-integral quadrature coupled method is not only to handle different type of boundary conditions, but also after being further modified via the introduction of an approximation procedure in this work, the time-varying system problem caused by human-structure interaction can be solved well. The analytical results of numerical simulations demonstrate that the modified differential quadrature-integral quadrature coupled method has higher reliability and accuracy compared with the mode superposition method. What's more, both of the two different passive control measures, the tuned mass damper and semi-rigid supported, have good performance for reducing vibrations. Most importantly, semi-rigid supported is easier to achieve the objective of reducing vibration compared with tuned mass damper in design stage of structure.

• Journal of Electrical Engineering and Technology
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• v.7 no.3
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• pp.396-400
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• 2012

Novel fabrication method of nanobridge array of various materials was proposed using suspended silicon nanowire array as a sacrificial template structure. Nanobridges of various materials can be simply fabricated by direct deposition with thermal evaporation on the top of prefabricated suspended silicon nanobridge arrays, which are used as a sacrificial structure. Since silicon nanowire can be easily removed by selective dry etching, nanobridge arrays of an intended material are finally obtained. In this paper, metal nanobridges of Ti/Au, around 50-200 nm in thickness and width, 5-20 ${\mu}m$ in length were fabricated to prove the advantages of the proposed nanowire or nanobridge fabrication method. The nanobridges of Ti/Au after complete removal of sacrificial silicon nanowire template were well-established and bending of nanobridge caused by the tensile stress was observed after silicon removing. Up to 50 nm and 10 ${\mu}m$ of silicon nanowire in diameter and length respectively was also very useful for nanowire templates.

• Steel and Composite Structures
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• v.44 no.3
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• pp.407-421
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• 2022

Prefabricated hybrid wind turbine towers (WTTs) are promising due to height increase. This study proposes the use of ultra-high performance concrete (UHPC) to develop a new type of WTT without the need to use reinforcement. It is demonstrated that the UHPC WTT structure without reinforcing bars could achieve performance similar to that of reinforced concrete WTTs. To simplify the design of WTT, a design approach for the calculation of stresses at the horizontal joints of a WTT is proposed. The stress distribution near the region of the horizontal joint of the WTT structure under normal operating conditions and different load actions is studied using the proposed approach, which is validated by the finite element method. A further parametric study shows that the degree of prestressing and the bending moment both significantly affect the principal stress. The shear-to-torsion ratio also shows a significant influence on the principal tensile stress.

• Steel and Composite Structures
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• v.45 no.5
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• pp.715-728
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• 2022

Closed steel supports of different shapes are used in mining and underground constructions. The supports are prefabricated from rolled, usually robust, steel profiles. The load carrying capacity of a support is considerably influenced by the active loading and passive forces. The passive forces are induced by interactions between the support and the surrounding rock mass. The analysis herein comprises three parts: The first part consists of structural geometry processing. The second part involves finding the numerical solution of a statically indeterminate structure for a specified load. The third part is calculation of the load carrying capacity and the components of internal forces and deformations. For this, the force method and numerical integration are used. The Winkler model is applied when the support interacts with the surrounding environment. The load carrying capacity is limited by the slip resistance of the connected parts and it is limited by reaching the ultimate state of the profile. This paper serves as a comprehensive reference for the determination of the load carrying capacity of closed steel supports and includes stepwise derivations of the governing formulas.

• Proceeding of KASS Symposium
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• 2008.05a
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• pp.49-52
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• 2008

Structural Wood is developed by purpose to make efficient use of wood resources. The biggest advantage of structural wood is stable as strength is high than wood product that is used by structure in existing. Order manufacture according to design details is available. It Is used to main structure elements to large spatial structure. Structure wood kind utilizes Glulam, prefabricated wood I-joists and laminated veneer lumber(LVL) and so on. Structural Design and construction of Open-air Stage Roof Structure is described in the presented paper. Architectural roof materials is used to PVF/PFLT membrane. Column and diagonal members is used to steel members(SS400), and Cantilever beam is used to Glulam assembled with different Grade laminations(10S-28B).

• Earthquakes and Structures
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• v.17 no.2
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• pp.233-244
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• 2019

In this work, we have studied the effects of different soil thicknesses, haunch heights, reinforcement forms and construction technologies on the seismic performance of a composite precast fabricated utility tunnel by pseudo-static tests. Five concrete specimens were designed and fabricated for low-cycle reciprocating load tests. The hysteretic behavior of composite precast fabricated utility tunnel under simulated seismic waves and the strain law of steel bars were analyzed. Test results showed that composite precast fabricated utility tunnel met the requirements of current codes and had good anti-seismic performance. The use of a closed integral arrangement of steel bars inside utility tunnel structure as well as diagonal reinforcement bars at its haunches improved the integrity of the whole structure and increased the bearing capacity of the structure by about 1.5%. Increasing the thickness of covering soil within a certain range was beneficial to the earthquake resistance of the structure, and the energy consumption was increased by 10%. Increasing haunch height within a certain range increased the bearing capacity of the structure by up to about 19% and energy consumption by up to 30%. The specimen with the lowest haunch height showed strong structural deformation with ductility coefficient of 4.93. It was found that the interfaces of haunches, post-casting self-compacting concrete, and prefabricated parts were the weak points of utility tunnel structures. Combining the failure phenomena of test structures with their related codes, we proposed improvement measures for construction technology, which could provide a reference for the construction and design of practical projects.