Advances in Design Procedures and Detailing of Structural Systems

The work presented in this dissertation covers a breath of topics within the field of structural engineering including: site assessment procedures for structures subjected to tsunami generated debris, the development of an innovative composite bridge system and shear connection and non-destructive evaluation of fully grouted post-tensioned bridge systems. Collectively, the original research contributions in each of three topics resulted in improvements to the overall design process of structural systems. The advancements to the design process presented in this dissertation include: assessment of demands on structural systems, developing new detailing of structural components, overall design changes to allow for improved inspection techniques and the development construction and fabrication methods for a prototype system.;This research effort was focused on developing site assessment procedures for structures subjected to tsunami generated debris impacts. A debris classification system was developed to group debris by the potential impact demand each item can generate.;An impact hazard region was developed which provides design engineers with a probable region over which large debris items will disperse in a tsunami event. Knowing the location of the debris origin and the assumed flow direction of the event the impact hazard region can be constructed for any tsunami prone location. The impact hazard region has been adopted by ASCE 7-16.;Analytical results utilizing the energy grade line (EGL) method were generated for a region of Hawaii and compared with results from a two-dimensional tsunami inundation simulation. Based on this comparison it was found that the EGL was under estimating the water velocity and inundation compared to the site-specific analysis. This under estimation was attributed to the discrepancy in runup elevation at the inundation limit provided by ASCE runup data and the corresponding elevation obtained for the same location using the available digital elevation model data. A modification to the EGL method to account for this discrepancy in elevation was proposed to improve the estimates of the EGL method, which extends the EGL transect past the inundation limit to an elevation on the DEM equal to the runup elevation provided by ASCE.;The result of this research project is the development of a precast steel/concrete composite highway bridge system whose beam components are light-weight and easy to erect and fabricate. This research effort examines the shear transfer mechanism between the concrete slab and WT web and developed construction methods for the prototype system.;A series of potential shear connector details were experimentally examined with push-off tests for the shear connection developed for the prototype system. A number of shear connector detailing parameters were investigated. If was found that increasing the hole size and bar size increased the shear capacity of the connection. Increasing the hole spacing resulted in a decrease in capacity and bending the rebar as opposed to using straight bars increased the capacity. Based on the experimental testing the connector details utilized in the prototype system design was 1.5 inch holes with ;The failure mechanism for the connectors was determined attributed to two mechanisms. In the case where no reinforcement was placed through the connector the ultimate strength is attributed to shearing of the concrete dowels and in the case where rebar was placed through every connector hole the ultimate strength is attributed to initial yielding of the reinforcing bar. A design equation to approximate the capacity of the shear connection was developed based on the observed failure mechanisms and experimental test data.;The prototype system shear details were designed based on the developed equation to approximate the shear capacity of the connection. Fabrication and construction methods were established for the newly developed prototype system, which were aimed at reducing fabrication cost and assuring critical dimensions of the system are maintained for all precast components. A laterally torsional buckling analysis of the sections was performed. The available AISC equations were modified based on concrete limit states for construction loading and applied to the individual precast components.;As part of this research effort a state of the art review of available NDE techniques that can be applied to fully grouted post-tensioned systems was conducted. Currently available NDE methods were grouped into four different categories by monitoring capabilities: grout voids identification, strand corrosion detection, identification of tendon location and determining loss of prestress. It was concluded that methods that can be directly integrated into future construction show the most promise for long term monitoring of post-tensioned tendons. A testing plan for two promising non-destructive testing methods, the electrically isolated tendon system and internal half-cell potential method, was developed. (Abstract shortened by UMI.).