ON THE EFFECTS OF CIRCULAR BOLT PATTERNS ON THE ...

CHAPTER 7
7. SUMMARY, CONCLUSION, AND RECOMMENDATIONS
7.1 Summary
The behaviors of the extended end-plate connections with both circular and square bolt pattern
configuration under static and cyclic loads are investigated. One hundred eighty two three-dimensional
nonlinear finite element models were developed and analyzed by using Abaqus 6.10-1 finite element
software. A comprehensive test matrix was developed to investigate the effectiveness of various
geometric parameters on the overall behavior of the connections. The parametric study conducted in this
research included seven bolt diameters, six end-plate thicknesses, three beam sizes, and two different
bolt pattern configurations bases on most commonly used range of variables .
The combined hardening plasticity model was used in order to model the behavior of the Grade-50
hot-rolled steel elements during the monotonic and cyclic loading. Isotropic hardening was used to model
the material properties of the high strength steel bolts.
Small sliding surface-to-surface was considered for all the contacts. The welds were assumed to be
rigid and modeled by tie-contact algorithm. The frictional surfaces accompanied by tangential force were
modeled by tangential-contact algorithm. The surface contact between the end-plate and column was
modeled by frictional contact using penalty stiffness.
To validate the numerical results obtained from the finite element analysis, the results obtained from
three full-scale experimental T-Stubs tests and five semi-rigid connections tests were collected. The
numerical models for each specimen was developed using the corresponding geometric and material
values. A close agreement between the numerical results and the experimental results were reported.
The regression analysis was conducted on the numerical results obtained from the finite element
analysis and the equations were developed to predict and model the hysteresis behavior of the extended
end-plate connections. The dependant variables i.e. moment capacity of the connection at yield (My),
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