A series of full-scale beam-to-column moment connection tests were completed to determine the effects of powder actuated fasteners (PAF) and puddle welds on the seismic behavior of steel moment connections.  In seismic regions, PAF are currently prohibited in the connection region (referred to as the protected zone) due to the concern of low-cycle fatigue fracture.  There is almost no information available in the literature regarding the seismic behavior of moment connections with PAF or puddle welds. Full-scale connection testing is the most accurate way to investigate the behavior of different moment connections with common defects and fasteners applied in the protected zone.  However, it is cost prohibitive to conduct full-scale testing programs that are sufficiently comprehensive to investigate a wide range of defect types, severity, and locations.  For this reason, it is desired to develop alternative methods of investigation.  A finite element (FE) model capable of simulating both the global deformation patterns and local buckling effects in a moment connection has been developed.  Validated FE models will allow for further evaluation through numerical simulation of additional configurations.  Furthermore, alternate, more economical, test configurations to experimentally investigate the effect of defects on steel moment connections were explored.  This report discusses the full-scale test setup, results and analysis of completed experimental testing, the development of an FE connection model, and the preliminary development of alternate test configurations. / Master of Science

A typical 1960s Type 2 Construction steel MRF hospital structure in Quebec, representative of a prevalent construction philosophy of the time, was investigated and modelled in OpenSees using an advanced strength degradation model. The structure was then subjected to a nonlinear time-history analysis (NLTHA) for Montreal (MTL) and Vancouver (VAN) ground motions and was found to be deficient under the design hazard levels. Retrofits were proposed for the two orthogonal frames at both sites using a performance-based approach. An experimental program determined that the connections had less ductility than expected and began deteriorating around 2.0% interstorey drift. The OpenSees model was updated according to the experimental connection behaviour and the predicted NLTHA performance of the structure worsened. The proposed retrofit designs for both orthogonal frames in both MTL and VAN were updated with the new connection behaviour and final retrofit designs were proposed.

A typical 1960s Type 2 Construction steel MRF hospital structure in Quebec, representative of a prevalent construction philosophy of the time, was investigated and modelled in OpenSees using an advanced strength degradation model. The structure was then subjected to a nonlinear time-history analysis (NLTHA) for Montreal (MTL) and Vancouver (VAN) ground motions and was found to be deficient under the design hazard levels. Retrofits were proposed for the two orthogonal frames at both sites using a performance-based approach. An experimental program determined that the connections had less ductility than expected and began deteriorating around 2.0% interstorey drift. The OpenSees model was updated according to the experimental connection behaviour and the predicted NLTHA performance of the structure worsened. The proposed retrofit designs for both orthogonal frames in both MTL and VAN were updated with the new connection behaviour and final retrofit designs were proposed.

Shear deformations are, generally, not considered in structural analysis of beams and frames. But shear deformations in members with low clear span-to-member depth ratio will be higher than normally expected, thus adversely affecting the stiffness of these members. Inclusion of shear deformation in analysis requires the values of shear modulus (modulus of rigidity, G) and the shear area of the member. The shear area of the member is a cross-sectional property and is defined as the area of the section which is effective in resisting shear deformation. This value is always less than the gross area of the section and is also referred to as the form factor. The form factor is the ratio of the gross area of the section to its shear area. There are a number of expressions available in the literature for the form factors of rectangular and wide flange sections. However, preliminary analysis revealed a high variation in the values given by them. The variation was attributed to the different assumptions made, regarding the stress distribution and section behavior. This necessitated the use of three-dimensional finite element analysis of rectangular and wide flange sections to resolve the issue. The purpose of finite element analysis was to determine which, if any, of the expressions in the literature provided correct answers. A new method of finite element analysis based on the principle of virtual work is used for analyzing rectangular and wide flange sections. The validity of the new method was established by analyzing rectangular sections for which closed form solutions for form factor were available. The form factors of various wide flange sections in the AISC database were calculated from finite element analysis and an empirical relationship was formulated for easy calculation of the form factor. It was also found that an empirical formula provided good results for form factors of wide flange sections. Beam-column joint sub-assemblies were modeled and analyzed to understand the contribution of various components to the total drift. This was not very successful since the values obtained from the finite element analysis did not match the values calculated using virtual work. This discrepancy points to inaccuracies in modeling and, possibly, analysis of beam-column joints. This issue needs to be resolved before proceeding further with the analysis. / Master of Science