Almost all bolted connections are eccentrically loaded. The American Institute of Steel Construction (AISC) permits the use of elastic and instantaneous center of rotation (IC) methods to analyze eccentric bolted connections. The elastic method normally yields relatively conservative designs and the IC method, which provides more realistic analyses, is rather complex and tedious. The current AISC manual provides tables for determining coefficient C, which is used to obtain the design strength of bolt group patterns. However, the tables provide values for only six angles of inclination (θ = 0°, 15°, 30°, 45°, 60°, and 75°). For other angles, a direct analysis using the IC method must be conducted. The straight-line interpolation between C values for loads at different angles may be non-conservative and it is not recommended by the AISC. This work develops an iterative algorithm for implementing the tedious IC method in the general analysis or design of eccentric bolted connections. To eliminate the tediousness of the IC method, a method is proposed to provide a reasonable result for all angles (between 0° and 90°) including those not being considered in the current AISC design tables. The proposed method is easy to implement but reasonably accurate, and replaces both the straight-line interpolation between C values for loads at various angles and direct analysis. This work eliminates the current limitations on AISC design. It provides a quick and reliable tool for preliminary design of eccentric bolted connection.
Lue, Dung-Myau; Liao, Cheng-Yen; Chang, Chien-Chien; and Hsu, Wei-Ting
"IMPROVED ANALYSIS OF BOLTED SHEAR CONNECTION UNDER ECCENTRIC LOADS,"
Journal of Marine Science and Technology: Vol. 25:
4, Article 2.
Available at: https://jmstt.ntou.edu.tw/journal/vol25/iss4/2