Crown feature effect evaluation on wind load for evergreen species based on laser scanning and wind tunnel experiments
3
Citation
37
Reference
10
Related Paper
Citation Trend
Abstract:
Abstract The wind load a tree withstood is mainly applied to its crown, whose morphology and structure directly affect the degree of wind load given a certain wind condition. Though the features of tree crown are relatively easy to measure, however, among them which is/are the determining factor and how they contribute to wind load remain unknown. In order to figure out how crown features of different tree species influence the wind load, the wind tunnel experiment was performed for 7 most used urban greening tree species, and laser scanning was used to measure the accurate crown features. The results derived by multiple linear model showed (1) Ficus concinna , Dracontomelon duperreanum , Ormosia pinnata and Bischofia javanica are recommended in urban greening for suffering the smaller wind load under the same conditions, whereas Schefflera macrostachya , Acacia confusa and Khaya senegalensis are inadequate towards the view of crown features; (2) crown features like crown horizontal ratio, windward side projection and porosity ratio are important in estimating wind load. Our study demonstrated that evaluating the wind load via crown features is feasible, and provided valuable suggestion for selecting idealized decorative trees in urban environment with a smaller wind load due to the crown features.Keywords:
Wind engineering
Despite advances in structural engineering, the damage caused by hurricanes to wood-framed houses continues to increase. The interaction of turbulent winds with houses and the induced structural load paths are not fully understood. Additionally, the small size of typical wind tunnel models limit feasibility to conduct pressure and structural load path studies. As part of an ongoing experiment investigating the interaction of turbulent winds with light-framed wood structures and the resulting structural loads, quantifying the three-dimensional wind flow characteristics around the structure is needed. The experimental study involves subjecting a one-third scale, geometrically accurate model of a light-framed wood gable roof residential building to realistic simulation of design wind speeds and wind flow characteristics, using UF's Hurricane Simulator and concurrently capturing pressure distribution and structural loads on the house model. A four-hole probe called the "Cobra Probe" is been used to characterize the wind field generated for the test. This paper presents preliminary work in validating the Cobra Probe which simultaneously measures wind velocities and turbulence intensities for all three orthogonal directions as well as the static pressure simultaneously. Using two different small wind tunnel facilities, comparisons were made with a hot-wire anemometer. Generally, the results were agreeable with the capabilities of the Cobra Probe far exceeding those of the hot wire anemometer. The test setup for the 1/3-scale model testing is also described.
Anemometer
Wind engineering
Pressure measurement
Scale model
Cite
Citations (0)
Vines are a group of plant that cannot stand erectly by themselves;they need to draw support from other plant or backstop to grow upwardly.Vines have many virtues,which are growing rapidly,needing land few,greening area largely,planting or managing easily.They are widely used in urban greening,especially in vertical greening.The urban vertical greening may divide into six forms:wall greening,column greening,fence greening,slope greening,pergola greening and roof greening.Vines' characteristics and application principles were summarized,and various selection and disposition technology of vines in different vertical greening were introduced.
Urban greening
Cite
Citations (0)
Vines are characterized by growing rapidly,occupying less space,giving larger greening area and easy planting or management.They are widely used in urban greening,especially in vertical greening.Application of vines in the urban greening was discussed with respects to its form and rules.
Urban greening
Urban landscape
Cite
Citations (0)