scholarly journals Prefabricated aluminium halls

2021 ◽  
Vol 73 (02) ◽  
pp. 141-151
Keyword(s):  
Bolted Joints ◽  
Structural Systems ◽  
Transport Costs ◽  
Low Weight ◽  
Multiple Uses ◽  
Norm Series

Prefabricated aluminium halls are usually temporary structures with multiple uses. Their biggest advantage is low weight resulting in lower transport costs and allowing for quick assembly. Today, there is a growing demand for aluminium halls to become permanent structures, and therefore, in meeting the requirements of EN 199x norm series, it is necessary to optimize the calculation aspect of conventional structural systems with reinforced bolted joints. An overview of the most common structural systems, typical aluminium profiles and joints with steel reinforcements, as well as a common approach for design and assembly, is presented in the paper.

Application of partial cross-section precast system to save the Amazon forest

2010 ◽  
Vol 37 (6) ◽  
pp. 878-886 ◽  
Author(s):  
Dênio Ramam Carvalho de Oliveira ◽  
Maurício de Pina Ferreira ◽  
José Guilherme Silva Melo
Keyword(s):  
Cross Section ◽  
Partial Cross Section ◽  
Structural Function ◽  
Amazon Forest ◽  
Structural Elements ◽  
Transport Costs ◽  
Flat Plates ◽  
Permanent Formwork ◽  
Low Weight ◽  
Material Economy

The Brazilian civil construction industry is one of the largest consumers of wood in the country. The majority of wood is used as formwork to build concrete structures and is discarded at the end of the construction process. This study presents an innovative structural system that uses a type of partial cross-section precast system with thin reinforced concrete flat plates, which are transported and assembled at the construction site and act as permanent formwork with structural function. The major advantages of this system include the reduction of transport costs; easier assembly of the structural elements because of its low weight; and the possibility of idealizing and designing rigid connections between structural elements, improvement of the structural behavior and postive impact on the material economy. This paper presents construction details, tests results, and some real cases where partial cross-section beams and columns were successfully applied in Brazil.

Assessment of the Dynamic Temperature Profile in Fire Loaded Sandwich Structures Based on Wood in Comparison with Conventional Structural Systems

2019 ◽  
Vol 887 ◽  
pp. 98-105
Author(s):  
Marie Rusinová ◽  
Miloš Kalousek ◽  
Jiří Šlanhof
Keyword(s):  
High Temperatures ◽  
Sandwich Structures ◽  
Construction Materials ◽  
Structural Systems ◽  
Internal Environment ◽  
Time Intervals ◽  
Load Bearing ◽  
Low Weight ◽  
In Fire ◽  
Very High

Fire safety is an important feature of healthy internal environment. If a fire breaks out, the interior of fire compartments within the building is exposed to very high temperatures and further phenomena accompanying the burning process. All of them impact the boundaries of the compartment structures, including the structures that are located inside them. Some structures serve the load bearing function hand in hand with fire barriers, some are only fire barriers. As to the dramatic increase of temperature, its impact upon the opposite surface of the fire separating structure should be considered, in particular regarding the behavior of the load bearing elements and their stability. This is topical at the present day, since the conventional construction materials are seen to give way to wooden sandwich structures that are preferred especially for their thermal insulation properties, low weight, small thickness and speediness of construction. The article uses dynamic simulation to illustrate how these modern structures react to high temperatures within specific time intervals, offering comparisons with traditional brick structures.

Testing of facade panels based on cassette profiles

2020 ◽  
pp. 43-48
Author(s):  
Y. Martynov ◽  
V. Nadolski ◽  
F. Viarouka
Keyword(s):  
Design Procedure ◽  
Wind Pressure ◽  
Design System ◽  
Structural Systems ◽  
Structural System ◽  
Wall Panel ◽  
Constructive Solution ◽  
Spatial Design ◽  
Low Weight ◽  
Load Tests

When designing modern enclosing structural systems, such qualities as reducing the complexity of installation, low weight, energy efficiency, aesthetic appeal and many others become more and more significant. Presented in this article new constructive solution of a self-supporting wall panel based on cassette profiles and profiled sheets combined into a single spatial design system to a large extent is able to meet these requirements. The article is devoted to the description, analysis and justification of a new constructive solution of a self-supporting wall panel based on cassette profiles; the design procedure was carried out using calculation methods, as well as using the basis of the results of tests in accordance with КP EN 1993-1-3; the data of experimental confirmation of the operability of the proposed structural system during load tests corresponding to the active wind pressure are presented.

Freeze fracture imaging and computer simulation of liposome structure: Membrane geometry and defects

1983 ◽  
Vol 41 ◽  
pp. 646-647
Author(s):  
Joseph A. Zasadzinski
Keyword(s):  
Liquid Crystalline ◽  
Freeze Fracture ◽  
Continuum Theory ◽  
Closed Surfaces ◽  
Straight Line ◽  
Low Weight ◽  
Concentric Spheres ◽  
Membrane Geometry ◽  
Dupin Cyclides ◽  
Limiting Case

At low weight fractions, many surfactant and biological amphiphiles form dispersions of lamellar liquid crystalline liposomes in water. Amphiphile molecules tend to align themselves in parallel bilayers which are free to bend. Bilayers must form closed surfaces to separate hydrophobic and hydrophilic domains completely. Continuum theory of liquid crystals requires that the constant spacing of bilayer surfaces be maintained except at singularities of no more than line extent. Maxwell demonstrated that only two types of closed surfaces can satisfy this constraint: concentric spheres and Dupin cyclides. Dupin cyclides (Figure 1) are parallel closed surfaces which have a conjugate ellipse (r1) and hyperbola (r2) as singularities in the bilayer spacing. Any straight line drawn from a point on the ellipse to a point on the hyperbola is normal to every surface it intersects (broken lines in Figure 1). A simple example, and limiting case, is a family of concentric tori (Figure 1b).To distinguish between the allowable arrangements, freeze fracture TEM micrographs of representative biological (L-α phosphotidylcholine: L-α PC) and surfactant (sodium heptylnonyl benzenesulfonate: SHBS)liposomes are compared to mathematically derived sections of Dupin cyclides and concentric spheres.

Representation of bolted joints in a structure using finite element modelling and model updating

2020 ◽  
Vol 14 (3) ◽  
pp. 7141-7151 ◽  
Author(s):  
R. Omar ◽  
M. N. Abdul Rani ◽  
M. A. Yunus
Keyword(s):  
Finite Element ◽  
Dynamic Behaviour ◽  
Model Updating ◽  
Complex Structure ◽  
Bolted Joints ◽  
Model Parameters ◽  
Fe Model ◽  
Bolted Joint ◽  
Fe Modelling ◽  
Joint Structure

Efficient and accurate finite element (FE) modelling of bolted joints is essential for increasing confidence in the investigation of structural vibrations. However, modelling of bolted joints for the investigation is often found to be very challenging. This paper proposes an appropriate FE representation of bolted joints for the prediction of the dynamic behaviour of a bolted joint structure. Two different FE models of the bolted joint structure with two different FE element connectors, which are CBEAM and CBUSH, representing the bolted joints are developed. Modal updating is used to correlate the two FE models with the experimental model. The dynamic behaviour of the two FE models is compared with experimental modal analysis to evaluate and determine the most appropriate FE model of the bolted joint structure. The comparison reveals that the CBUSH element connectors based FE model has a greater capability in representing the bolted joints with 86 percent accuracy and greater efficiency in updating the model parameters. The proposed modelling technique will be useful in the modelling of a complex structure with a large number of bolted joints.

A Novel Approach: Trans-ascending Aorta Balloon Aortic Valvuloplasty via Sternotomy for Treating Severe Valvular Aortic Stenosis in a Low-Weight Infant

2014 ◽  
Vol 17 (1) ◽  
pp. 25 ◽  
Author(s):  
Lei Gao ◽  
Qin Wu ◽  
Xinhua Xu ◽  
Tianli Zhao ◽  
Wancun Jin ◽  
...  
Keyword(s):  
Aortic Stenosis ◽  
Transesophageal Echocardiography ◽  
Severe Aortic Stenosis ◽  
Ascending Aorta ◽  
Balloon Aortic Valvuloplasty ◽  
Congenital Aortic Stenosis ◽  
Novel Approach ◽  
Low Weight ◽  
Aortic Valvuloplasty ◽  
Peak Gradient

<p><b>Background:</b> Severe congenital aortic stenosis in infants is a life-threatening congenital heart anomaly that is typically treated using percutaneous balloon aortic valvuloplasty.</p><p><b>Methods:</b> The usual route is the femoral artery under radiographic guidance. However, this procedure may be limited by the small size of the femoral artery in low-weight infants. An infant weighing only 7 kg with severe aortic stenosis (peak gradient was 103 mmHg) was successfully treated with a novel approach, that is trans-ascending aorta balloon aortic valvuloplasty guided by transesophageal echocardiography.</p><p><b>Results:</b> The patient tolerated the procedure well, and no major complications developed. After the intervention, transesophageal echocardiography indicated a significant reduction of the aortic valvular peak gradient from 103 mmHg to 22 mmHg, no aortic regurgitation was found. Eighteen months after the intervention, echocardiography revealed that the aortic valvular peak gradient had increased to 38 mmHg and that still no aortic regurgitation had occurred.</p><p><b>Conclusions:</b> In our limited experience, trans-ascending aorta balloon aortic valvuloplasty for severe aortic stenosis under transesophageal echocardiography guidance effectively reduces the aortic peak gradient. As this is a new procedure, long-term follow up and management will need to be established. It may be an alternative technique to treat congenital aortic stenosis in low-weight patients.</p>

Determinants of Brazilian Exports by Levels of Technological Intensity: A Gravity Model Analysis Using the PPML Estimator

2019 ◽  
Vol 10 (9) ◽  
pp. 861-879
Author(s):  
Edson Roberto Vieira ◽  
◽  
Daniel Henrique Alves Reis ◽  
Keyword(s):  
International Market ◽  
Positive Influence ◽  
Gravity Models ◽  
Transport Costs ◽  
Consumer Market ◽  
Technology Products ◽  
The Us ◽  
Trading Partners ◽  
Negative Impacts ◽  
Technological Intensity

The objective of this study is to analyze the determinants of Brazilian exports by levels of technological intensity in the period 2000-2015. Gravity models were estimated for total of the exports and for each type of exports by levels of technological intensity, using the PPML-estimator. The study indicates that there is a process of concentration of Brazilian exports in low technology and medium-low technology products, at the same period in which China's share of total Brazilian shipments abroad grew. Estimates of empirical gravity models have shown that the income and size of the consumer market of Brazil’s trading partners seem to have the greatest positive influence on the Brazilian exports. Indications of this study are that the Brazil should continue to diversify its trading partners to minimize the impacts of a possible reduction of the economic growth of large trading partners (such as China and the US) on its exports and increase its exports of products with greater technological intensity. The results also highlight the need for Brazil to make greater efforts to increase its competitiveness in the international market to reduce the negative impacts of transport costs on the final prices of products exported by the country.

Sign in / Sign up

Export Citation Format

Share Document