Evaluation of the bolt and weld eccentricities of conventional single-plate shear connections

Abstract

This study aims to investigate the accuracy of bolt eccentricity (eb) and the required weld size for connecting shear tab to the support presented in 15th edition of AISC Steel Construction Manual for conventional single-plate (CSP) connections. In addition, the available equation for prediction of the weld eccentricity (ew) was evaluated. For this purpose, by changing different parameters, 72 specimens were designed in accordance with the AISC Manual. The designs are in a way that the bolt fracture becomes the governing limit state. Investigated parameters include loading type, bolt pretensioning force, beam span (Lb), beam depth (db), the number of bolts (n) and the spacing between bolt and weld lines (a). All specimens were analyzed through finite element (FE) method using ABAQUS software. Results indicate that the manual prediction for eb is non-conservative and inaccurate. Although the available equation for ew was able to reasonably predict ew, this equation yields to a non-conservative prediction in most cases. Furthermore, results indicate that among all investigated parameters, only n, Lb and a have remarkable effects on eb and ew. In order to propose alternative equations for eb and ew in terms of effective parameters, artificial neural network was utilized which resulted in predictive models with acceptable level of accuracy. Regarding the weld size, a procedure was proposed in which the weld must fail after the bolt fracture. Results show that, using this procedure, leads to a safer weld design in comparison with the use of AISC Manual suggestion for weld design (w = 5/8tp).