Block shear is a mode of failure in which a steel member fails in tension along one plane and shear on a perpendicular plane along the fasteners. The design process for block shear has been at the center of debate since it first appeared in the 1978 AISC Specification and has evolved over the years. This thesis investigated the block shear design equations as they have progressively changed from the 1978 provisions for Allowable Stress Design (ASD) to the 2005 provisions for Load and Resistance Factor Design (LRFD). Block shear strength capacities were calculated for multiple designs involving coped beams, angles, and structural tees. These analytical values were compared to physical test findings available in the literature. The results of this study compare the different strength predictions to one another, as well as benchmark the AISC provisions to actual physical testing strengths. The comparisons were also used to determine whether the ASD and LRFD specifications follow similar trends. Good agreement between the predicted capacities and the results from physical testing was observed for a majority of the geometries investigated. However, capacity predictions based on increasing the number of rows of bolts for a coped beam and changing the length of the outstanding leg for an angle or tee connection were found to disagree with the test results. A finite element study was also completed to further explore the influence of changing the length of the outstanding leg of tee connections because these geometries showed considerable disagreement between the calculated capacities and the test data.

This research took place in 3 stages. In the first stage, lignin graphene (LG) was synthesized using a catalytic thermal conversion process. In stage 2, the time and temperature correlations for polyvinyl acetate (PVAc) and phenol resorcinol formaldehyde (PRF) adhesives were found and PRF showed stronger correlation when doped with carbon nanomaterials. Stage 3 evaluated the effect of the nanomaterials on radio frequency (RF) heating time and adhesive strength. It was found that all versions of the PRF adhesive resulted in higher shear strength values when cured in room temperature for 24 hours or in an oven at 170 °F for 30 minutes. The combination of PRF + 0.5 % LG and 120 s RF heating resulted in significantly higher block shear strengths when compared to the other RF heating durations. Pine lumber was selected as it is the single most important commercial/structural species in North America, by volume. A substantial portion of pine is directed to glue-laminated timber and cross-laminated timber. Both industries use or can use RF curing and as such both may benefit from improvements developed herein.

Yes / Currently, steel reuse is only a marginal practice. To facilitate deconstruction and efficient reuse of steel components, an innovative connection system was proposed. This system adopts a ‘Block Shear Connector (BSC)’ that allows beam length to be standardised and suitable for a wide range of different sizes of the supporting members within the same planning grid. This paper presents the experimental and numerical studies of a beam-to-beam connection using BSCs. The BSC used was made from a standard universal HE / UC section and was bolted to the beams by using partial depth end plates. The experimental results provided the shear resistance, momentrotation, failure behaviour, demountability and reusability of the steel components. Further numerical simulation conducted investigated the effect of some key parameters (steel strength, thickness of BSC web, thickness of BSC flange, initial bolt stress) on the behaviour of the connections. The results obtained highlighted the demountability of this innovative bolted connection system and the reusability of structural components. / European Commission: Research Fund for Coal and Steel (RFCS-2015, RPJ, 710040)

Block shear is a limit state that should be accounted for during the design of the steel tension members. This failure mechanism combines a tension failure on one plane and a shear plane on a perpendicular plane. Although current design specifications present equations to predict block shear load capacities of the connections, they fail in predicting the failure modes. Block shear failure of a structural connection along a staggered path may be the governing failure mode. Code treatments for stagger in a block shear path are not exactly defined. A parametric study has been conducted and over a thousand finite element analyses were performed to identify the parameters affecting the block shear failure in connections with multiple bolt lines and staggered holes. The quality of the specification equations were assessed by comparing the code predictions with finite element results. In addition, based on the analytical findings new equations were developed and are presented herein.

The I-35W Bridge over the Mississippi River in Minneapolis, MN had a catastrophic failure in the main span of the deck truss in 2007. This collapse has brought significant attention on the gusset plate connections in steel truss bridges throughout the U.S. Steel truss bridge gusset plate design has not received much focus in the past 40 years, and there is a lack of consensus within the design profession on the procedures to evaluate, design, and rate these critical elements. In the short term, based on the best available information on the gusset plate design, the Federal Highway Administration (FHWA) has issued preliminary guidance. Although some experimental research has been conducted on the ultimate strength of gusset plates, much of this work has been directed toward the performance of tension members and their connections. There has been limited experimental work on the compression capacity and stability of gusset plates, but most of this work is relevant primarily to bracing connections common in building structures. This research focuses on comprehensive experimental and analytical studies on steel truss bridge gusset plate behavior. The studies include comparisons of advanced analytical models with the responses from large-scale experimental tests using discrete and innovative full-field measurements. The calibrated finite element analysis models are then utilized to study a variety of gusset plate configurations. Improved mechanistic idealizations that better capture the observed behavior in the experiments and analytical studies are proposed as the result of this work. The design checks recommended in this thesis present a comprehensive methodology for determining the ultimate gusset plate resistance. This research provides a large database of original results that will be useful for future similar studies. In addition, this research provides modeling procedures that permit the study of steel truss bridge connections and their adjacent framing members using truss bridge sub-assemblies. Based on the comprehensive analytical studies, simple and accurate design calculation procedures to assess the nominal ultimate strength of steel truss gusset plate connections are recommended for steel truss bridge gusset plate connections.