Reliability of Bolted Wood Connections

Abstract

This report analyzes the implied reliability of current practice for the design of bolted wood connections. All U.S. data available to the writer were used. The resistance distribution was taken to be normal, and the coefficient of variation was obtained by pooling data from several sources, as long as the moisture condition, grain direction, side‐plate material, and species were alike. The reliability index for softwood connections is about 5; the index for hardwood connections is about 20% greater than that for softwood connections. A comparative study of data from six sources showed that reliability does not depend upon bolt length‐to‐diameter ratio, and the effects of wood moisture content and side‐plate material (steel or wood) are minimal. Two new codes are briefly examined and compared with current practice. Both of these codes contain radically reformed design criteria for bolted wood connections. The comparison shows that both new codes maintain the present level of reliability.