Lawrence A. Soltis

Bolted-connection design

Recent failures of bolted connections have raised doubts about our knowledge of their design. Some of the design criteria are based on research conducted more than 50 years ago. This paper compares results found in the literature, using the European Yield Theory as a basis of comparison, to summarize what is known about bolted-connection design and what needs further research. By putting all this information in one place we hope to help engineers and architects design safer timber buildings and structures. In general, the strength is known for a single bolt in a wood side member connection loaded parallel to grain in compression. Less is known for single bolts in tension, loaded perpendicular to grain or having steel side members. The distribution of strength in a multiple-bolt connection is known for up to four bolts in a row. In summarizing the literature we confirm the spacing, end, and edge distance requirements in current multiple-bolt design for Douglas-fir connections. No information exists for distribution of strength or spacing requirements for multiple rows of bolts. The effects of other factors such as fabrication tolerances, duration of load, and preservative or fire treatment are not known. Fabrication tolerances appear to have a large effect on connection strength, but this effect has not been quantified.