Thin-walled panels are widely used in different engineering applications. Bridge and building plate girders, box columns and girders, frame bracing systems, liquid and gas containment structures, shelters, offshore structures, ship structures, slabs, hot-rolled W-shape steel profiles, steel plate shear wall systems and many other naval and aeronautical structures are examples of engineering elements that use plate of various thicknesses, according to their applications. The knowledge of the actual behavior of plates in such structures can be, of course, helpful in understanding the overall behavior of the structures. In general, plates in thin-walled structures may be under various types of loading, such as shear loading. Yielding of material and geometrical buckling of plates are two independent phenomena which may well interact with each other in shear panels. Depending on the material properties, SLENDERNESS, aspect RATIOs, and boundary conditions of perfectly flat plates, the yielding may occur before, after or at the same time as buckling. Buckling in slender plates is a local and sudden phenomenon followed by large out-of-plane displacements and loss of stiffness. Slender plates are capable of carrying considerable post-buckling additional loads due to stresses in the inclined tension fields. On the other hand, a plate with low SLENDERNESS RATIO yields before buckling and thus, no post-buckling capacity is expected. In between, plates with moderate SLENDERNESS RATIOs, experience both material yielding and geometrical nonlinearity almost at the same time. In the present paper, behavioral characteristics of shear panels with simple or clamed boundary conditions are studied. Three different materials (carbon steel, stainless steel and aluminum) and various plate SLENDERNESS RATIOs are considered for adopting the finite element method. Results of nonlinear static analyses of different shear panels show that slender plates, depending on the SLENDERNESS RATIO, carry a relatively small shear load in the elastic stage until the occurrence of shear buckling. However, additional capacity in the post-buckling stage of these plates, prior to yielding, is significantly large. The plates reach their ultimate shear capacity slightly after yielding and their post-yield capacity is not significant. Note that the ultimate shear strength of slender plates is considerably lower than their nominal shear yield strength. In plates with intermediate SLENDERNESS RATIO, yielding of material and buckling occur concurrently (simultaneously). They carry a relatively large shear load in the elastic stage before yielding/buckling. They have also some post-buckling/post-yield reserves before failure. The ultimate shear strength of moderate plates is somehow lower than their nominal shear yield strength (yield strength in shear). In stocky plates, yielding precedes buckling, thus the shear capacity in the elastic stage before yielding is significant. The plates have some post-yield capacity and the ultimate load is coincident with the occurrence of plastic buckling (if happens). The ultimate shear strength of stocky plates is almost equal to their nominal shear yield strength. Moreover, results of quasi-static cyclic analyses of different shear panels show that the energy absorption capability, as expected, is very sensitive to the SLENDERNESS RATIO of panels. By decrease in the SLENDERNESS RATIO (increase of thickness), amount of the absorbed energy is substantially increased. For a specific SLENDERNESS RATIO, steel shear panels exhibit higher energy absorption than panels with aluminum materials. However, aluminum material of this study has higher yield strength than that of carbon steel and stainless steel materials. This, of course, highlights the important role of the modulus of elasticity in the energy dissipation capability of shear panels. Yield strength of the material and panel boundary conditions have no important role in the amount of dissipated energy, compared to the material modulus of elasticity.

The purpose of this study was to investigate which equation (Linear, Exponential equation and quadratic) can describe exactly the interaction effect of particle size and adhesive percent and predict mechanical properties of particleboard (modulus of rupture, modulus of elasticity and bending strength). For this work three levels of density including 0.65, 0.7, and 0.75 g/cm3 and also, three levels of adhesive content including 8, 9.5, and 11% and four levels of SLENDERNESS RATIO of particles including 46.35, 33.7, 21.51 and 12.87 were used. After conducting the experiment and preparing the data, three kind of equation (linear, quadratic and Exponential equation) for each mechanical property based on SLENDERNESS of particles, density and adhesive percent obtained. The result indicated there was no correlation between mechanical properties of particleboard and quadratic equation but there were good correlations between linear and Exponential equation. Also the result indicated that Exponential equation can describe efficiently the simultaneous effect of SLENDERNESS and adhesive present on the mechanical properties of particleboard, and it can predict better mechanical properties than linear equation.

The purpose of this study was to compare the chemical compositions and biometric features of stem and cone fibers (length, diameter, and wall thickness) and the derived coefficients of loblolly pine (Pinus taeda) in Astara district, Gilan province. Discs from stem and cone were randomly taken and the chemical compositions and biometric features were measured employing the TAPPI standard test methods and Franklin macerating technique, respectively. The biometric coefficients were estimated as well. Statistical analyses of the results indicated that the average cellulose content in stem and the cone were 54.83% and 27.57%, respectively. Lignin was estimated to be 32.57% in the stem and 34% in the cone. Furthermore, extractives soluble in ethanol, acetone and water from stem wood were measured as 92%, 1.97% and 7.04% respectively. The relevant values for pine cone were 1%, 2.45% and 7.28%, respectively. According to the results of statistical analysis, there was significant difference (a=5%) between the results measured from cones and the stem except for the SLENDERNESS RATIO. Regarding the length, diameter, lumen diameter and flexibility factor, the P. taeda stem possesses a higher value compared with cone and the runkel RATIO was higher in cones compared to stem.

Beech is one of the richest, most important, and most economical forest types of Iran. Total height variable is one of the main forest morphometric variables. The height variable of trees is used in forest biometrics: determining volume, height curve drawing, and computation SLENDERNESS coefficient of trees. One of the crucial factors in calculating the diameter at breast height is the size of tree. The forest of 90 trees of Hajikola Mazandaran forest was selected for this research; five samples per class were randomly chosen to evaluate SLENDERNESS coefficient beech. Accelerators increase the height of beech trees until they reach 40 cm in diameter, higher. The minimum average height of 19. 20 meters in diameter classes 30-50 cm & maximum average 27. 55 meters a height diameter classes 100-120 cm. The average SLENDERNESS coefficient 34. 58 stability was witnessed as accepted. SLENDERNESS coefficient in the increase of tree diameter shows a decreasing trend. Reducing the SLENDERNESS coefficient of beech tree at a young age is because of the competition for crown which results in height growth and low diameter growth. And thereafter, the increased diameter growth and decreased height growth occur. Age and diameter growth increase the stability of the tree.

In the present study, the effect of material properties and SLENDERNESS RATIOs on the nonlinear behavior characteristics and energy dissipation behavior of steel plates (including stainless steel, mild structural steel and low yield point steel) under shear loading is studied using FEM. First, the steel shear plates with respect to their SLENDERNESS RATIO and nonlinear behavior are qualitatively and quantitatively classified into very slender, slender, moderate, stocky and very stocky. To quantitatively determine the SLENDERNESS classes for each steel materials, modified theoretical relationships are presented separately using statistical analyses of the obtained results for various steel plates. Also, new relationships for assessment of inelastic (moderate plates) and plastic (stocky plates) buckling loads are proposed, that can estimate buckling loads for moderate and stocky plates more accurately compared to the available theoretical relationships in AASHTO. In general, with increasing SLENDERNESS RATIO, the capability of steel plates for energy dissipation, due to the occurrence of buckling and the resulted pinching in the hysteresis loops, is gradually decreased. In the case of very stocky plates, the capability of plates for energy dissipation is only dependent on the material yield stress, while in the class of slender, moderate and stocky plates, it is dependent to both of the SLENDERNESS RATIO and material yield stress. In the case of very slender steel plates, the capability of different steel plates for energy dissipation, disregarding the material yield stress and the plate SLENDERNESS RATIO, seems to be similar, less or more, for various steel materials.

This paper presents behaviour of normal concrete, ultrahigh-strength concrete, engineered cementitious composite, lightweight concrete, self-consolidating concrete and crumb rubber concrete under confinement. Forty-six circular, square and rectangular concrete-filled steel tube columns with varying SLENDERNESS are tested under axial compression. Failure modes, axial load– displacement responses and stress– strain characteristics are analysed as well as concrete confined strengths are determined based on experimental results and existing models. The performance of existing confined strength models is evaluated and modified to accommodate different types of high-performance concretes and column shapes. The modified model improves the prediction of confined concrete strength with a mean predicted-to-experimental RATIO of 1. 05 as shape and concrete type factors are introduced.

SLENDERNESS coefficient of trees, defined as the RATIO of total height to diameter at breast height (DBH), is frequently used as resistance index of trees to wind throw. By measuring DBH and total height of 1379 trees, the relationships between SLENDERNESS coefficients and trees DBH were investigated for five major tree species in a broadleaved Hyrcanian forests of Iran, Kheyroudkenar-Noshahr, including beech (Fagus orientalis Lipsky), hornbeam (Carpinus betulus L.), maple (Acer velutinum Boiss.), alder (Alnus subcordata C.A.M.) and oak (Qercus castaneifolia C.A.M.). Tree SLENDERNESS coefficients were found to be negatively correlated with DBH. The graphical results indicated that about 75% of the sampled trees had a SLENDERNESS coefficient lower than 80 and the range of variation is between 20 to 173. The most of difference among the SLENDERNESS coefficients of tree species were found in diameter class below 30 cm. Maximum SLENDERNESS coefficients observed in the valleys and northern aspects, while minimum in karstic phenomenons and southern aspects. No correlation was found between tree SLENDERNESS coefficients and stand density.

In this paper, the behavior of masonry columns under working load has been studied. The effect of cracking on compression area of column or variation of moment of inertia of column along its height has been considered. The analytical solution for the critical load and deflection of the column is presented. A numerical example is presented to illustrate the method. The proposed approach has provided more realistic behavior of the masonry columns and proved to give an optimized critical load. The implications of the proposed study on the Indian code have also been presented.

Background and objectives Study of SLENDERNESS coefficient and crown RATIO of trees in forest parks to determine the stability of the stands against the wind is one of the important issues in the park management. The most important reason is the intensive presence of families and vehicles in these areas, which can cause irreparable damage if trees fall. Therefore, this study was conducted to investigate the sensitivity of Eldar pine trees in different parts of Sorkheh Hesar Forest Park to wind throw. Attempts have also been made to evaluate the suitability of diameter at breast height, as a variable that is simple and inexpensive to measure, to predict the crown RATIO and SLENDERNESS coefficient as two important indicators for determining the susceptibility of trees to wind throw. Materials and methods After a field survey, 14 patches were selected for sampling so that sampling sites were well distributed throughout the park. A total of 151 trees were randomly selected and their diameter at breast height, total height, trunk height, SLENDERNESS index and canopy RATIO were calculated. Independent t-test was used to examine differences between tree lines and patches. Regression analysis was also performed to model the relationship between diameter-SLENDERNESS index as well as diameter-crown RATIO. Results Based on the results, the average basal area of the measured trees was 0. 034 m2 and their average volume was 0. 208 m3. Considering the variety of planting spaces, basal area and volume of pine stands were calculated 9. 45-54. 4 m2. ha-1 and 57. 8-332. 8 m3. ha-1 respectively. The results showed that the average SLENDERNESS index was 57. 29% and that 0. 7% of the trees were in unstable conditions. The average crown RATIO was 0. 557 and based on this index, 2. 6% of trees were unstable. There was a significant difference between the forest patches and the tree lines along the streets in terms of crown length, canopy RATIO, trunk height, and SLENDERNESS index. The linear model had a significant fitting to the data of diameter-SLENDERNESS index as well as diameter-crown RATIO, with error percentage of 13 and 11. 7% and coefficient of determination of 0. 28 and 0. 17, respectively. Conclusion In general, pine trees in Sorkheh Hesar National Park are in a stable condition and a small percentage of them need biomechanical study of wood tissues in order to determine the maximum tolerable wind speed and take precautions such as pruning. Also, diameter at the breast height in various plantings in terms of density, alone is not enough to predict the SLENDERNESS coefficient and the crown RATIO of the trees. It is necessary to measure the total height and crown height of the trees to determine the SLENDERNESS coefficient and crown RATIO. Due to the effect of the area and shape of tree patches in the incidence and severity of wind throw, it is necessary to consider the shape of the spots as a teardrop that is directed towards the prevailing winds in the region to minimize the risk of falling in busy places.

Proper designing of green space in educational centers increases vitality and ensures the safety of users and reduces costs. The purpose of this study was to estimate the lack of root and canopy growth space of the most important green space trees of Yazd University. At first 124 pine and 102 elm trees were randomly selected in different parts of the University and their morphological characteristics were measured. The height/diameter coefficient was used to determine the susceptibility to wind-throw. To determine the shortage of canopy growth space, the canopy area of ​​5% of the largest trees and to calculate the shortage of root growth space, the British standard were used. Then, classification of frequencies was done. Results showed that the mean height coefficient of pine and elm were 56. 85 and 51. 21 respectively. About 87. 1% of the pines and 42. 2% of the elms were in a stable condition. About 96% of the elm trees and 94. 4% of the pine trees had insufficient planting distance and therefore, do not have enough space to reach the maximum dimensions of the crown. According to the results, 77% of pines and 54% of elm trees lacked root growth space. Tomographic examination via ultrasonic technology showed decay only in some broken trees. Based on the results, it is recommended to assign enough space for the growth of canopies and roots in order to reduce the possibility of uprooting, before designing the planting areas and building curbs and sidewalks.