Ultimate Load-Deflection Characteristics and Failure Modes of Ceiling Diaphragms for Farm Buildings

Load-deflection characteristics and failure modes of metal-clad, timber-framed, screw-fastened ceiling diaphragms are presented. Diaphragms, 2.44 m x 6.10 m (8 ft x 20 ft) and 2.44 m x 4.88 m (8 ft x 16 ft), were built and tested as deep beams. Loads were applied to simulate wind loads on ceilings of farm buildings. Variables included panel profile, rib orientation, size of supporting grid, diaphragm size, spacing of end-fasteners, and effect of an opening at midspan

AN ECONOMIC ANALYSIS OF THE RELATIONSHIP OF POVERTY AND INCOME INEQUALITY IN RURAL WEST VIRGINIA

Ordinary and two-stage least square regressions were used to examine the major determinants of poverty and income inequality with cross-sectional data of 38 rural counties of West Virginia. The empirical findings confirm the possibility of simultaneity between poverty and income inequality and poverty level is the main determinant of increased levels of income inequality. The proportions of population in welfare, population of age 65 or older, female-headed households, people unemployed, and the level of inequality contributed to increased poverty levels. The proportion of employment shares in finance, insurance and real estate, and per capita income contributed to reduced poverty levels. But, per capita income, the proportion of human capital stock, and the proportion of employment shares in manufacturing contributed to reduced income inequality.Food Security and Poverty,

USING TIME SERIES TO STUDY DYNAMICS OF SWEAT RATES OF HOLSTEIN COWS EXPOSED TO INITIAL AND PROLONGED SOLAR HEAT STRESS

Sweating is a very important way for cows to cope with heat stress. We are interested in the ability of Holstein cows to sustain high sweat or evaporation rates when exposed to solar radiation. There were two solar heat stress treatments: onset and prolonged. The onset data provided an opportunity to examine the impact of sudden exposure to a solar thermal load. The prolonged data allowed us to examine the impact of exposure to solar heat stress for an expended period (5 hr). Two questions of interest were: Do cows sweat at a constant or cyclic rate? Is there a difference in the dynamics of the two treatments: onset and prolonged solar heat stress? The data were examined for stationarity. In the time domain, we fit ARIMA models and estimated the parameters. In the frequency domain, we used nonparametric spectral estimation to identify cyclic patterns in the sweat rates. The usefulness of each technique for analyzing the dynamics of sweat rates is discussed

An expert system for optimizing computer aided design of post frame buildings

A procedure has been developed to optimize designs of metal-clad post-frame buildings using an expert system. The novel part of the study is the development of a procedure that extends the solution of an engineering problem from a conventional algorithmic Computer Aided Design (CAD) program to be used by the knowledge base of an expert system. The expert system then uses this information to optimize the design based on specified rules. The system shows a procedure for linking and sharing information between CAD and expert system programs.This is the publisher’s final pdf. The published article is copyrighted by the American Society of Agricultural Engineers and can be found at: http://elibrary.asabe.org/toc_landing.asp?conf=aeaj.Keywords: Knowledge base, Decision making, CAD, Frame analysisKeywords: Knowledge base, Decision making, CAD, Frame analysi

Finite Element Model for Predicting Stiffness of Metal-Plate-Connected Tension-Splice and Heel Joints of Wood Trusses

A finite element model that predicts axial stiffness of metal-plate-connected (MPC) tension-splice and heel joints of wood trusses is developed. The commercial software ABAQUS was used in developing the model. The model was based on: (1) the assumption that the joints are two-dimensional, (2) plane-strain modeling, and (3) the assumption that the properties of the wood and metal plate are linearly isotropic. The interface between the wood and the teeth of the metal plate is modeled with a finite sliding formulation. Contact surfaces (rather than contact elements) model the slip of the teeth of the metal plate and shear at the wood-tooth interface. The tangential contact properties are set to a specified coefficient of friction while the normal contact properties are set to a "hard" contact formulation, allowing for a possible separation of the nodes after contact is achieved. Model predictions are validated against experimentally measured stiffness values obtained in the literature. The data cover two wood species and three levels of modulus of elasticity (MOE). On the average, the model predicts within 5% of the experimentally measured stiffness values. The unique features of the model include: (1) accounting for friction at the tooth-wood interface, (2) accounting for tooth slip, (3) requiring no empirical factor (such as foundation modulus) in predicting axial stiffness, and (4) using the same methodology in modeling tension-splice and heel joints

Analysis of metal-plate-connected wood trusses with semi-rigid joints

Metal-plate-connected wood trusses with semi-rigid joints were investigated by the matrix method of structural analysis. The element-stiffness matrix and fixed-end forces of an individual member with one or both ends semi-rigid were derived as modifications of the idealized cases. The case of unequal elastic connections at two ends of a member can also be handled by this method of analysis. When one end is semi-rigid, the other end may be specified as pinned, rigid, or semi-rigid. The truss was analyzed for three different joint assumptions: pin, rigid, and semi-rigid joints. The truss performance, based on deflection, varied greatly depending on the joint assumption. Including semi-rigid-joint behavior in the analysis of a wood truss decreased maximum deflection by 34% compared with the pinned-joint assumption and maximum moment by 13% compared with the rigid-joint assumption. By incorporating semi-rigid behavior of joints, more accurate member forces can be obtained enabling closer prediction of actual truss behavior.This is the publisher’s final pdf. The published article is copyrighted by the American Society of Agricultural Engineers and can be found at: http://elibrary.asabe.org/toc_landing.asp?conf=t1.Keywords: Element-stiffness matrix, Matrix method, Wood engineering, Fixed-end force