Relatively few research efforts have focused on splice length requirements for reinforced masonry, despite the significant impact of these requirements on the safety, economy, and constructability of masonry walls. The Canadian masonry provisions for splice lengths in CSA S304.1-04 are taken directly from the Canadian concrete design standard, CSA A23.3-04, and thus do not necessarily reflect factors unique to masonry construction. Provisions in American masonry standard TMS 402-13/ACI 530-13/ASCE 5-13 are based on test results of double pullout specimens, but may be overly conservative due to shortcomings of the specimen type chosen. The purpose of this study is to examine the splice lengths needed for flexural masonry elements reinforced with bar sizes typically used in Canadian masonry construction. In this study, 27 wall splice specimens and 12 double pullout specimens were constructed. The wall splice specimens were tested horizontally in four point loading, while the double pullout specimens were tested in direct tension. Results from the double pullout specimen testing suggest that the techniques used at the University of Saskatchewan (U of S) are reasonably similar to those of the National Concrete Masonry Association (NCMA), and are thus adequate to assess current provisions in the American and Canadian standards. A predictive equation for the tensile resistance of spliced reinforcement was developed from the results of the wall splice specimen testing. This predictive equation was then adjusted to incorporate an adequate margin of safety for calculating splice length requirements for design purposes, using a five percent quantile approach. The adjusted predictive equation was then extrapolated to determine the splice lengths corresponding to the nominal yield strength of the reinforcement. These splice lengths were compared to current code provisions. It was found that the current CSA S304.1-04 Class B provisions, used almost exclusively in construction, are conservative for No. 15, 20, and 25 bars. In contrast, the TMS 402-13 provisions were overly conservative for all three bar sizes. Changes to the bar size factors of the current provisions for both codes were recommended to bring better consistency to the requirements of the two codes, and thus ensure the safety, economy, and constructability of masonry walls.

Unbonded post-tensioned concrete block (UPCB) shear walls are an effective seismic force resisting system due to their ability to contain expected damage attributed to their self-centering capabilities. A few design procedures were proposed to predict the in-plane flexural response of UPCB walls, albeit following only basic mechanics and/or extensive iterative methods. Such procedures, however, may not be capable of capturing the complex nonlinear relationships between different parameters that affect UPCB walls’ behavior or are tedious to be adopted for design practice. In addition, the limited datasets used to validate these procedures may render their accuracy and generalizability questionable, further hindering their adoption by practitioners and design standards. To address these issues, an experimentally-validated nonlinear numerical model was adopted in this study and subsequently employed to simulate 95 UPCB walls with different design parameters to compensate for the lack of relevant experimental data in the current literature. Guided by mechanics and using this database, an evolutionary algorithm, multigene genetic programming (MGGP), was adopted to uncover the relationships controlling the response of UPCB walls, and subsequently develop simplified closed-form wall behavior prediction expressions. Specifically, through integrating MGGP and basic mechanics, a penta-linear backbone model was developed to predict the load-displacement backbone for UPCB walls up to 20% strength degradation. Compared to existing predictive procedures, the prediction accuracy of the developed model and its closed-form nature are expected to enable UPCB wall adoption by seismic design standards and code committees. / Thesis / Master of Applied Science (MASc)

<p>An experimental investigation was conducted to analyze the effectiveness of repairing and retrofitting the intersections of flanged concrete block shear walls using surface-bonded fiber-reinforced polymer (FRP) laminates for seismic load applications. A total of 18 specially designed flange-web intersecting wall assemblages were tested using 5 different schemes. Tests included wall intersections reinforced with unidirectional FRP with the fibers oriented perpendicular to loading direction (90°), parallel to loading direction (0°) and bi-directional (90°/0°), (90°/0°)2 and (45°/135°) to applied load direction. The behaviour of each wall specimen is discussed with respect to its failure mode, strength and deformation characteristics. Results showed that the laminates significantly increased the shear strength of concrete block shear walls junction. In addition, the fiber orientation influenced the failure mode, strength and stiffness. Moreover, depending on the fiber orientation, a significant enhancement to the post-peak load energy absorption capacity of the web-flange intersection can occur. The improved post-peak behaviour addressed the benefits of retrofitting concrete block wall intersections for seismic load applications. The FRP-retrofitted specimens were capable of reaching between 90% to 390% increase in strength compared to the umetrofitted specimen constructed with traditional steel joint reinforcement.</p> / Thesis / Master of Engineering (MEngr)