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Number of results: 7
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Abstract

Labor productivity in building construction has long been a focused research topic due to the high contribution of labor cost in the building total costs. This study, among a few studies that used scaled data that were collected directly from measuring equipment and onsite activities, utilized neural networks to model the productivity of two main construction tasks and influencing factors. The neural networks show their ability to predict the behaviors of labor productivity of the formwork and rebar tasks in a test case of a high-rise building. A multilayer perceptron that had two layers and used sigmoid as its activation function provided the best effectiveness in predicting the relations among data. Among eleven independent factors, weather (e.g., temperature, precipitation, sun) generally played the most important role while crew factors were distributed in the mid of the ranking and the site factor (working floor height) played a mild role. This study confirms the robustness of neural networks in productivity research problems and the importance of working environments to labor productivity in building construction. Managerial implications, including careful environmental factors and crew structure deliberation, evolved from the study when labor productivity improvement is considered.
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Authors and Affiliations

Duc Anh Nguyen
1
ORCID: ORCID
Dung Quang Tran
1
ORCID: ORCID
Thoan Ngoc Nguyen
1
ORCID: ORCID
Hai Hong Tran
1
ORCID: ORCID

  1. Hanoi University of Civil Engineering, Department of Building and Industrial Construction, 55 Giai Phong Street, Hanoi, Vietnam
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Abstract

The metropolis of Barcelona is one of the first ten Europe's urban agglomerations. The geographic and natural conditions of the city - located in area between the sea and the forested mountain ranges running parallel to the coast and divided by broad river valleys - have considerably influenced the formation of its hybrid urban structure. The heart of the agglomeration is still Barcelona, established by the Phoenicians in a natural port at the foot of the Montjiuc hill, growing together with its neighbouring towns for more than two thousand years now, incessantly filling one fragment of natural landscape after another with urban fabric. Monumental edifices and high-rise buildings erected in all historic periods have been inorming visitors of the power of teh city and the same time defining places which are important for its urban composition and status. Recent decades have brought no revolutionary changes in this trend. What was changed, though, are the architectural forms of those most emblematic structures in the scale of the metropolis.

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Authors and Affiliations

Mateusz Gyurkovich
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Abstract

In this paper, a frame structure based on the locally resonant (LR) mechanism of phononic crystals (PCs) is designed on account of the wide application of frame structures in high-rise buildings, and the band structures, displacement fields of eigenmodes, and transmission power spectrums of corresponding finite structure are calculated by finite element (FE) method. Numerical results and further analysis demonstrate that a full band gap with low starting frequency can be opened by the frame structure formed by periodically combining soft and hard materials, and the starting frequency can be further lowered with the adjustment of corresponding geometric parameters, which provides a theoretical basis for the studies on vibration insulation and noise reduction of high-rise buildings.

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Authors and Affiliations

Yukun Wang
Denghui Qian
Jinghong Wu
Feiyang He
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Abstract

The stiffness of structural elements (columns, beams, and slabs) significantly contributes to the overall stiffness of reinforced concrete (RC) high-rise buildings (H.R.B.s) subjected to earthquake. In order to investigate what percentage each type of element contributes to the overall performance of an H.R.B. under seismic load, the stiffness of each type of element is reduced by 10% to 90%. A time history analysis by SAP2000 was performed on thirteen 3D models of 12-story RC buildings in order to illustrate the contribution of column stiffness and column cross sections (rectangular or square), building floor plans (square or rectangular), beam stiffness and slab stiffness, on building resistance to an earthquake. The stiffness of the columns contributed more than the beams and slabs to the earthquake resistance of H.R.B.s. Rectangular cross-section columns must be properly oriented in order for H.R.B.s and slender buildings to attain the maximum resistance against earthquakes.

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Authors and Affiliations

D.-P.N. Kontoni
A.A. Farghaly
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Abstract

In the structural reinforcement of a high-rise residential building in Changzhou city, Jiangsu province, China, the technology of prestressed steel bar strengthening shear wall, which was initiated in China, was applied. Combined with the engineering quality inspection report, the project characteristics and the requirements of the construction party, various methods, such as increasing cross-section reinforcement method and staged replacement concrete reinforcement method, were comprehensively used to treat and reinforce the structures with different quality problems and different parts. In general, the stress and strain of the newly added part always lags behind the stress and strain of the original structure. This will cause the stress of the original structure is too high and the deformation is large, while the stress of the new part is still at a low level, which cannot fully play its role and its due reinforcement effect. Prestressed steel bar reinforced shear wall technology, through the prestressed steel bar on the prestressed steel bar, which is a good solution to this problem, avoid the phenomenon of stress lag, and ultimately not only shorten the construction period of reinforcement, but also ensure the quality of reinforcement and user use area, successfully passed the reinforcement special acceptance. The monitoring data also proved that the reinforcement measures adopted are safe, reliable and economical. This paper can provide reference for the effective development of similar reinforcement projects.
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Authors and Affiliations

Cheng Heping
1
ORCID: ORCID
Yao Wenchi
2
ORCID: ORCID

  1. Prof., Changzhou Vocational Institute of Engineering, School of Civil Engineering, Changzhou, Jiangsu, 213164, China
  2. Eng., Jiangsu Digital Construction Engineering Research Center, Changzhou, Jiangsu, 213164, China
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Abstract

This paper discusses the protection and development of the cityscape with the use of digital techniques to determine the location of tall buildings. It presents the methodology applied while developing the 2020–2021 Composition Study of Szczecin. The study was commissioned by the City, and its results were included in the Study of Conditions and Directions for Spatial Development of Szczecin adopted in 2022. The aim was to define a framework for the development of high-rise buildings, while at the same time protect historical vistas preserved in the public consciousness. The paper discusses various methods of digital cityscape analysis based on the use of 3D city models, e.g.,Visual Protection Surface (VPS) and Visual Impact Size (VIS), which allow to indicate the maximum height of new buildings that would enable to protect strategic views and to analyse the impact of new buildings on the city space. The process resulted in the formulation of precise guidelines and the drafting of a long-term and sustainable spatial policy for the cityscape of Szczecin. The research has a universal formula and may also be applied to other cities.
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Authors and Affiliations

Klara Czyńska
1
ORCID: ORCID
Paweł Rubinowicz
1
ORCID: ORCID
Waldemar Marzęcki
1
ORCID: ORCID

  1. West Pomeranian University of Technology in Szczecin, Faculty of Architecture
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Abstract

The growth in high-rise building construction has increased the need for hybrid reinforced concrete and steel structural systems. Columns in buildings are the most important elements because of their seismic resistance. Reinforced concrete (RC) columns and steel columns were used herein to form hybrid structural systems combining their distinct advantages. Eleven 3D building models subjected to earthquake excitation with reinforced concrete beams and slabs of 12 floors in height and with different distributions of mixed columns were analyzed by the SAP2000 software in order to investigate the most suitable distributions of a combination of reinforced concrete and steel columns. Top displacements and accelerations, base normal forces, base shear forces, and base bending moments were computed to evaluate the selected hybrid structural systems. The findings are helpful in evaluating the efficiency of the examined hybrid high-rise buildings in resisting earthquakes.

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Authors and Affiliations

D.P.N. Kontoni
A.A. Farghaly

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