COMPRESSION RESISTANCE AND SHEAR STRENGTH OF Guadua angustiolia CULMS AFTER DRILLING OF THE NODE DIAPHRAGM Resistencia a la compresión y al corte de culmos de Guadua angustifolia después de la perforación del diafragma del nudo Titulo Corto: Culm strength and diafragm - Resistencia del culmo y diafragma

The preservation of guadua (Guadua angustifolia) culms is an important process which affects their quality after harvesting and their subsequent utilization as a raw material in handicraft, furniture and construction. Boron and boric acid are frequently used in the preserving solution (PS). To ease the adsorption the culm diaphragm is usually drilled before immersion in the PS. We performed a factorial experiment to determine the possible effects of drilling the culm diaphragm on compression and shear strength. Two measures of culm maturity were considered. The traditional measure is defined by the external features of the culms and another is based on the time since culm emergence. Variance analyses did not show any significant (p > 0.05) difference in mechanical properties when the diaphragm was drilled. Nevertheless, those culms with maturity defined using the traditional approach had significantly lower values of compression and shear strength. In addition, culms with higher moisture content were significantly stronger.