Propiedades mecánicas de las conexiones simples entre elementos de bambú laminado

APPLICABILITY OF THE YIELD THEORY MODEL TO PREDICT THE LATERAL STRENGTH BEHAVIOR OF SINGLE CONNECTIONS WITH GLUED LAMINATED GUADUA BAMBOO Juan C.Atoche1, Fernando Ramirez2, y Juan F. Correal3 ABSTRACT Compression tests in single connections using glued laminated Guadua bamboo (GLG) members were conducted to determine the applicability of the Yield Theory Model (YTM) to predict the lateralstrength behavior of GLG connections. The results show that YTM properly predicted the lateral strength behavior of tested GLG connections. The YTM was in good agreement with experimental results of the lateral strength of GLG connections loaded parallel to the mean member grain and that correspond to yield mode Im. The definition of yield load could be affecting the over-estimating for the others GLGconnections. A calibration factor of 1.50 is established when the YTM use the GLG bearing strength from the equations proposed by Atoche (2009) to predict conservatively lateral strength of GLG connections.

INTRODUCTION The structural performance of laminated bamboo has become a topic of worldwide interest in recent years. In Colombia, the Universidad de los Andes is conducting a research projectaimed to study the structural behavior of glued laminated Guadua bamboo (GLG). This two year project has as one of its major objectives the evaluation of the structural potential of GLG, and this scope is being accomplished through studies on GLG structural elements and on GLG mechanical connections. Research work was focused on using experimental and analytical methods with the purpose of takingadvantage of them to develop the best possible knowledge of this new material. There is no available information on GLG single mechanical connections using dowel-type fasteners. However, the GLG features indicate that its structural application will be similar to those of wood. Thus, test method standards and analytical mechanics approaches currently used in wood engineering provide the basis tothis investigation. The theoretical method most accepted for the design of single wood connections is the Yield Theory Model.
1Graduate Research Assistant, Civil Engineering Department, Universidad de los Andes, Bogotá, Colombia. 2Associate Professor. Civil and Environmental Engineering Dept., Universidad de los Andes, Bogotá, Colombia. 3Director of Integrated Lab and Assistant Professor. Civiland Environmental Engineering Dept., Universidad de los Andes, Bogotá, Colombia.

The purpose of this study was to evaluate the applicability of the YTM to predict the lateral strength behavior of GLG connections. In order to accomplish this objective, tests were carried out to determine the lateral strength behavior of GLG connections with threaded bars and nails as fasteners. Additional testswere carried out with the aim to find material properties required by YTM

LITERATURE REVIEW In most wood design specifications, the YTM proposed by Johansen (1949) has been adopted as the basis for predicting the lateral strength of bolted and nailed connections. In the United States Aune and Patton Mallory (1986), McLain and Thangjitham (1983), and Soltis (1986) established the applicabilityof the YTM to nails and bolts in wood. Before 1991, the American National Design Specification for Wood Construction (NDS) has a connection design section based only on empirical formulations. With the adoption of the YTM and an equation format specification, a significant breakthrough towards an engineering mechanics approach for the design of dowel-type connections was accomplished (Heine 2001).Single fastener connection design is now on a firm mechanics base and it is less ambiguous and confusing (McLain 1991). Predictions by the model seem to agree more closely to experimental data of parallel to grain loaded connections than to connections subjected to perpendicular to grain loading (Soltis and Wilkinson, 1987). Compared to other analytical formulations, YTM entails closed-form and...