scholarly journals Aeroelastic Response of Suspended Pedestrian Bridges Made of Laminated Wood and Hemp

2020 ◽  
Vol 5 (7) ◽  
pp. 60
Author(s):  
Fabio Rizzo
Keyword(s):  
Steel Structure ◽  
Wind Tunnel Experiments ◽  
Aeroelastic Response ◽  
Flutter Speed ◽  
Pedestrian Bridges ◽  
Torsional Frequency ◽  
Structural Configurations ◽  
Steel Cables ◽  
Two Degree Of Freedom

The work described in this paper investigated, by calculating critical flutter speed, the aeroelastic response of suspended pedestrian bridges made of a laminated wood structure and hemp cables and compared them to bridges with a steel structure and harmonic steel cables. Critical flutter speed was estimated using a numerical two degree of freedom (2-DOF) generalized deck model based on finite-element modal analysis. The critical flutter speeds of two sets of 25 different structural configurations, obtained by varying the deck chord and the permanent deck loads, made of steel and of laminated wood respectively, were estimated using experimental flutter derivatives obtained from 30 wind tunnel experiments. One of the most significant results was that pedestrian bridges made of laminated wood and hemp have a higher torsional frequency than those made of steel and that this affects critical flutter speed. A case study was performed and discussed by analyzing the structural and aeroelastic response of a 250 m pedestrian bridge with a 12 m deck chord and two approximately 32 m tall towers.

scholarly journals Environmental Education as a Tool for Sustainable Development: Case study of Lekki-Lagos

2017 ◽  
Vol 1 (1) ◽  
pp. 15-22
Author(s):  
M. N. Chukwu ◽  
S. J. Kadafur
Keyword(s):  
Environmental Education ◽  
Sample Population ◽  
Traffic Jam ◽  
Qualitative Survey ◽  
Private Organizations ◽  
Pedestrian Bridges ◽  
Significant Difference ◽  
Grass Root ◽  
The Government

The study examines the strength of environmental education in Lekki-Lagos and its impact on community and grass-root development by considering a targeted sample population comprising some respondents that are living or working in Lekki community in Lagos. A qualitative survey was conducted using participatory observation, interviews, and a structured questionnaire. The questionnaire was validated through peer review and pilot testing. Data collected were summarized and computed using descriptive statistics while a paired t-test and Turkey’s HSD test were used for further analysis. Results showed that 92% of the respondents affirmed that environmental education impacted positively on the community attracting the government, non-governmental and private organizations to help in developing the area through construction of roads, pedestrian bridges, drainages and sea embankments thus reducing flooding, man hour loss due to traffic jam and rate of pollution. There was also a decrease in loss of lives and properties. Investors were attracted to Lekki, reducing poverty and social imbalance thus increasing community development. There is a significant difference between the state of Lekki now and before the intervention of public-private practice in developing the area (P< 0.05). It is recommended that the government and other stakeholders should collaborate on a higher scale to enhance developing the unreached communities.

Investigating traffic-related PM exposure on and under pedestrian bridges: A case study in Xi'an, China

2018 ◽  
Vol 9 (5) ◽  
pp. 877-886 ◽  
Author(s):  
Zhaowen Qiu ◽  
Jianhua Song ◽  
Caihong Hao ◽  
Xiaoxia Li ◽  
H. Oliver Gao
Keyword(s):  
Pedestrian Bridges

scholarly journals EXPERIMENTAL, NUMERICAL AND ANALYTICAL INVESTIGATIONS OF WIND-INDUCED NET PRESSURES FOR INDUSTRIAL BUILDINGS WITH ENVELOPE POROSITIES

2016 ◽  
Vol 7 ◽  
pp. 58
Author(s):  
Vanessa Saubke ◽  
Rüdiger Höffer
Keyword(s):  
Spatial Distribution ◽  
Numerical Model ◽  
Wind Tunnel ◽  
External Pressure ◽  
Navier Stokes ◽  
Industrial Building ◽  
Wind Tunnel Experiments ◽  
Industrial Buildings ◽  
External Pressures

The magnitude and the spatial distribution of wind-induced net pressures (external and internal) on buildings are frequently discussed among research communities and construction industries. This paper deals with this topic based on a case study about an industrial building in Denmark, which was damaged due to the wind impact during a storm when a large part of the roof covering was blown off. In order to detect the reason for the damage the wind-induced loads were studied by i) wind tunnel experiments on the external pressures due to different wind directions, ii) analytical investigations of internal pressure due to envelope porosities and planned openings and iii) numerical analyses for the internal and the external pressure. The Reynolds averaged Navier-Stokes (RANS) method is employed to build a numerical model. The experimental, analytical and numerical results are compared with the indicated characteristic loads from the Eurocode.

scholarly journals Assessment of technical condition and repair of steel structure elements on the example of fire damage in a warehouse building

2019 ◽  
Vol 284 ◽  
pp. 02001
Author(s):  
Andrzej Ambroziak ◽  
Paweł Piotrkowski ◽  
Tomasz Heizig
Keyword(s):  
Steel Structure ◽  
External Source ◽  
Technical Condition ◽  
Actual Condition ◽  
Test Results ◽  
Structural Elements ◽  
Site Investigations ◽  
Laboratory Test Results ◽  
Repair Procedure

The paper analyses a case study on the structural assessment of warehouse building partially damaged by fire caused by external source (fire of lorries close to the building). The authors focus on the site investigations and laboratory test results prior to assessing actual condition of the structural elements. Both strengthening concept and repair procedure of a steel column are addressed here. A short literature survey in the paper regards fire damages and its impact on the entire structural systems and its members.

A Case Study Of The Use Of Ultrasonic Peening For Upgrading A Welded Steel Structure

2011 ◽  
Vol 55 (9-10) ◽  
pp. 56-67 ◽  
Author(s):  
Stephen J. Maddox ◽  
M. J. Doré ◽  
Simon D. Smith
Keyword(s):  
Steel Structure ◽  
Welded Steel ◽  
Ultrasonic Peening

Carbon Footprint Analysis of Fibre Reinforced Polymer (FRP) Incorporated Pedestrian Bridges: A Case Study

2012 ◽  
Vol 517 ◽  
pp. 724-729
Author(s):  
Jian Guo Dai ◽  
Tamon Ueda
Keyword(s):  
Construction Industry ◽  
Carbon Footprint ◽  
Prestressed Concrete ◽  
Environmental Friendliness ◽  
Pedestrian Bridge ◽  
Reinforced Polymer ◽  
Pedestrian Bridges ◽  
Fibre Reinforced Polymer ◽  
Footprint Analysis

This paper presents a case study on the carbon footprint of a fibre reinforced polymer (FRP)-incorporated pedestrian bridge in comparison with a conventional prestressed concrete (PC) one. The CO2 emission is used as an index and calculated for both the material manufacturing and the construction processes. It is shown that using an FRP-incorporated pedestrian bridge to replace a conventional prestressed concrete (PC) bridge may reduce the CO2 emission by 18% and 70%, respectively, during the material manufacturing and construction periods, leading to a total reduction by about 26%. Such reduction is expected to be more significant if the life-cycle CO2 emission is accounted for, since the former type of bridge is free of corrosion and almost maintenance-free. Therefore, FRP-incorporated bridges may become a more competitive alternative to conventional reinforced concrete (RC) or PC ones with the increasing attention paid on the sustainability and environmental friendliness of construction industry by our society.

scholarly journals Sustainability Perspective to Support Decision Making in Structural Retrofitting of Buildings: A Case Study

Systems ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 78
Author(s):  
Rui A. F. Oliveira ◽  
Jorge P. Lopes ◽  
Maria Isabel Abreu
Keyword(s):  
Environmental Impact ◽  
Steel Structure ◽  
Embodied Energy ◽  
Case Study Approach ◽  
Study Approach ◽  
Building Retrofit ◽  
Building Market ◽  
Structural Option ◽  
Support Decision Making

The reuse of existing materials in buildings can give a contribution to sustainable practices such as a balance in embodied energy, water, and emission reduction. However, it is not always possible to maintain the existing structural materials because some different technical variables could hamper their usability, namely seismic reinforcement needs, fire safety protection, conservation state, and new legal requirements. The paper follows a case study approach for assessing the technical and environmental performances of structural options for old building retrofitting works. All structural options were analyzed through the results of several categories of environmental impact. Some parameters of a retrofitting management system were also used to frame in a comprehensive way the technical constraints pertaining to building retrofitting works. The structural option choice was taken by the owner with the contribution of the design team and the construction manager of the construction project as well as the results of interviews with other construction professionals, considering the variables related to technical suitability and environmental impact. The results of the study show that the steel structure is the solution that best addresses the technical constraints of the building retrofit works and minimizes environmental impact. The results of the study also suggest that the consideration of other variables other than the technical ones can contribute to the effective functioning of the renovation subsegment of the building market. Some suggestions for further studies to enhance the results of this work are put forward.

A Case Study Aiming to Mitigate Pipe Vibrations Using CFD and Dynamic Stress Analysis Approach

2020 ◽  
Author(s):  
Amar Phatak ◽  
Gaurav Bhende ◽  
Nilesh Mane
Keyword(s):  
Flow Simulation ◽  
Steel Structure ◽  
Design Stage ◽  
Operating Personnel ◽  
Real Risk ◽  
Depth Analysis ◽  
Process Plants ◽  
The Times ◽  
Engineering Practices

Abstract Piping vibrations in process plants are rarely analyzed or anticipated correctly during the ‘design Stage’. Most of the times ‘in -depth’ analysis is not carried out during ‘design stage’ except following few good engineering practices. As a result, few pipes can show excessive vibrations during operations that fall under the ‘danger’ zone. The vibrating pipe transfers the vibrations to the steel structure and these vibrations are experienced by operating personnel causing a ‘safety hazard’. The real risk is loss of containment due to unacceptable vibrations and eventual fatigue failure of pipe and or structure. The reason resulting in vibrations can be connection of pipe with rotating equipment, the vibration of structure on which the pipe is supported, flow inside the pipe, noise level or slug / water hammer. Here, the authors present a case study of a vibrating pipe beyond the accepted limit and how the pipe vibrations which are being transferred to supporting platform are minimized. The analytical results obtained by software simulations are benchmarked against actual readings measured at the site. The paper also provides the mathematics and its application to solve a practical vibration problem. It provides a systematic approach starting from generic calculations until a detailed flow simulation. In the end, it provides guidelines to select rubber and viscous dampers. The innovative part of the case study is the usage of specially designed rubber mounds which have yet not been used for pipe vibrations.

scholarly journals Hypersonic Aeroelastic Response of Elastic Boundary Panel Based on a Modified Fourier Series Method

2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Xiyue Zhou ◽  
Lifeng Wang ◽  
Jingnong Jiang ◽  
Zhu Su
Keyword(s):  
Fourier Series ◽  
Time Domain ◽  
Series Method ◽  
Aeroelastic Response ◽  
Flutter Speed ◽  
Elastic Boundary ◽  
Fourier Series Method ◽  
Length Width ◽  
Time Domain Response ◽  
Elastic Boundary Conditions

In this paper, an analytical method is proposed to directly obtain the aeroelastic time domain response of the elastic boundary panel. Based on a modified Fourier series method (MFSM), the vibration analysis of elastic boundary panels is carried out, after the dynamics equation of the panel is obtained. Then, the vibrational functions are combined with the supersonic piston theory to establish the aeroelastic equation. The aeroelastic time domain response of the panel is obtained to analyze the flutter speed of the panel more intuitively. Finally, the flutter speeds of panels with different length-width ratios, thicknesses, and elastic boundary conditions are discussed in detail.

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