Factors Influencing the Preload Level of high Strength Bolts for Structural Steel Connections
Tomme: LVII (LXI) Fascicle: 1 | 2011
Pages: 125-138
Abstract text:
For steel structures subjected to reversible or shock loads all current design codes impose the use of high strength pre-tensioned bolts. The behaviour of pre-tensioned connections, in addition to proper dimensioning, is strongly influenced by the assembly process as well by the need to ensure the pretension level taken into consideration when designing the connection. The pre-tension stress of a bolt varies in time and is characterized by three specific values: the initial pre-tension, represented by the value of tensile stress after the first tightening, the residual pretension value, represented by the value of tensile stress once all of the bolts have been tightened, the final pre-tension represented by the value of tensile stress at the time of operation. The value of the final pre-tension force is closely related to the value of the original pre-tension force. The value of the initial pre-tension force can be controlled directly and with great precision hence the correct initial pre-tension force is essential to ensure the desired behaviour of the connection. The detailed methods of pre-tensioning the bolts used in structural steel connections are presented. The advantages and disadvantages of the methods presented in the specifications are highlighted. At the end of the paper are chronologically listed different patents of direct tension indicator devices.
Key Words:
steel structures; bolted connections; bolt preload; bolt tighte-ning methods.
Author(s) Information
All documents with a 
icon require
Adobe Acrobat installed on your computer
