The Experts below are selected from a list of 240 Experts worldwide ranked by ideXlab platform

Ram B Naik - One of the best experts on this subject based on the ideXlab platform.

  • wind analysis of bridges by Gust Load Factor method
    International Journal of Research, 2017
    Co-Authors: Ram B Naik
    Abstract:

    Wind is a widespread and costly natural hazard to mankind . Adequate of wind effect in design is essential for the safety and economics of structure. Wind engineering is an emerging discipline. Even though there is vast amount of literature available in this field, it is dispersed in journals and technical reports that relate to the discipline of structural engineering, fluid dynamics, mechanical engineering, atmospheric sciences, and others. Because of this dispersion architects and engineers have difficulty in leaning and understanding problems associated with wind Load. The bridges are made of different materials. Timber, masonry, concrete and steel are the primary materials which are most common in the design of bridges. The timber bridges are constructed only over small spans and for temporary purpose. The masonry bridges can also be used to cover only the small spans. The ratio of permissible stress to weight for masonry is fairly small and in spans larger than about 12 m the dead Load of the masonry will make its use uneconomical. Reinforced concrete is probably the most popular material for permanent highway bridges in India. Balanced cantilever bridges and pre stressed concrete girder bridges can be used for spans up to 60 m. Concrete arch has been used for spans of 200 m. In India for railway bridges steel is used for very small spans to very large spans. Bridges are built for many purposes e.g. carrying a highway, a railway track, for support of water pipes, gas or oil pipes etc. Nearly all important bridges are built primarily for purposes of carrying a highway or railway over a river, canal, another highway or railway or some other natural or artificial obstacle.

Nuaa Nanjing - One of the best experts on this subject based on the ideXlab platform.

  • Gust Load Calculation of Canard Airplanes with Pitching
    Transactions of Nanjing University of Aeronautics and Astronautics, 1994
    Co-Authors: Nuaa Nanjing
    Abstract:

    Gust Load of airplanes,especially of canard airplanes, is analysed and calculated when the airplane pitch is taken into account.The differential equations of the airplane motion in a Gust are deduced based on the assumptions that the airplane can pitch with the life increment of the horizontal tail considered. The life increment caused by the airplane pitching is considered. These are different from the assumptions of NACA R1206.It is found that for static stability airplanes especially for canard airplanes which usually have the first stalling characteristics of the canard surface,the airplane pitching causes a little effect on the maximum Gust Load Factor,although the airplane takes rather more time for penetrating a Gust wave. The two-seat canard airplane AD200 is taken as an example. The result shows that the airplane pitching in a Gust has a negligible effect on the Gust-Load for light canard airplanes.

Wu Yue - One of the best experts on this subject based on the ideXlab platform.

  • comparative study on the Gust Load Factor in the Load codes and standards of five countries
    Journal of Harbin Engineering University, 2010
    Co-Authors: Wu Yue
    Abstract:

    A comparison was made between the Loading code for building structure of several countries: the Chinese code(GB50009-2001),USA code(ASCE7-98),Japanese code(RLB-AIJ1993),Canadian code(NBC1990),and Australian code(AS1170.2).In the first section,the Gust Load Factor(GLF) method proposed by Davenport and used in major international codes and standards was summarized.In the second section,a comparison was made among several main parameters affecting GLF,including the mean wind speed(pressure) profile,turbulence intensity,and wind speed spectrum.(ASCE7-98),(RLB-AIJ2004),(NBC1990),and(AS1170.2) considered GLF as a constant,equal to the "displacement Gust response coefficient";the Gust response coefficient in Chinese codes and standards referred to a quantity changing with height,equal to the "inertial force Gust response coefficient".The result shows that since USA codes and standards(ASCE7) select an average interval of 3s and other countries' codes and standards select longer average intervals,the American Gust Load Factor is smaller than in other countries.Australian codes and standards(AS1170.2) consider similar second order fluctuating wind pressure.Canadian codes and standards(NBC) have larger turbulence intensity than other countries',making their wind spectral coefficient larger,and their background Factor and resonance Factor smaller than other countries.Japanese codes and standards(RLB-AIJ) have the smallest turbulence intensity,which leads to the biggest size reduction Factor and the smallest Gust Load Factor.

Chen Yong - One of the best experts on this subject based on the ideXlab platform.

  • Random wind-induced dynamic response of long-span roof to thunderstorm downbursts in the time domain
    2008
    Co-Authors: Chen Yong
    Abstract:

    Thunderstorm downbursts,which are known that the wind characteristics differ significantly from boundary layer winds,are defined as an outburst of damaging strong winds on or near the ground.When such events occur,the roofs will induce a large amount of buffeting responses and cause failures.This paper presents a deterministic-stochastic hybrid model to simulate a downburst.Wood's velocity profile for the vertical profile and Holmes' empirical model are utilized to generate the mean wind.The fluctuation is generated by stationary Gaussian stochastic process.Based on the multi-modal acceleration method and the theory of equivalent wind Load,a new method is provided to estimate the wind-induced response of long-span roofs.Through the rigid and aeroelastic model wind tunnel test,the pressure field on roof is researched and compared.Using the time histories of downburst wind Loads,the dynamic responses of structure can be obtained in the time domain.The distribution of Gust Load Factor and Gust displacement Factor on the flexible roof surface has been studied and compared,respectively.In practice,the procedure and the results presented here may be used to estimate the dynamic response of long-span roof subjected to severe downburst winds.

Lou Wen-juan - One of the best experts on this subject based on the ideXlab platform.

  • Random discrete wind-induced dynamic response of long-span roof in disaster windy environments
    2007
    Co-Authors: Lou Wen-juan
    Abstract:

    When wind flows around long-span flexible roofs,the flexible roofs will be exist large wind-induced buffeting responses.It is found that the contribution of higher vibration modes can not be ignored in the analysis of wind-induced dynamic responses for long-span roof structures.The characteristics of the random filtered white noise excitations such as wind Load and the method generating a filtered white noise vector with spatial correlation using a white noise process have been investigated in the present study.The primary purpose of the study is to develope a Multi-Modal Precise Integration Method for Random Discrete Analysis(MPIMRDA) combined with the rigid and aeroelastic model wind tunnel test to estimate the wind-induced response of long-span roofs.The distribution of Gust Load Factor and Gust displacement Factor on the flexible roof surface has been studied and compared,respectively.The results agree well with the finite element method.Finally,it is found out that the multi-modal precise integration method for random discrete analysis is really a valid method with simplicity,accuracy and fast calculation speed.