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.

No / Optimum multi-layered feed-forward neural network (NN) models using a resilient back-propagation algorithm and early stopping technique are built to predict the shear capacity of reinforced concrete deep and slender beams. The input layer neurons represent geometrical and material properties of reinforced concrete beams and the output layer produces the beam shear capacity. Training, validation and testing of the developed neural network have been achieved using 50%, 25%, and 25%, respectively, of a comprehensive database compiled from 631 deep and 549 slender beam specimens. The predictions obtained from the developed neural network models are in much better agreement with test results than those determined from shear provisions of different codes, such as KBCS, ACI 318-05, and EC2. The mean and standard deviation of the ratio between predicted using the neural network models and measured shear capacities are 1.02 and 0.18, respectively, for deep beams, and 1.04 and 0.17, respectively, for slender beams. In addition, the influence of different parameters on the shear capacity of reinforced concrete beams predicted by the developed neural network shows consistent agreement with those experimentally observed.

Neste trabalho, são estudas as verificações da punção global segundo a revisão da NBR 6118. A partir da análise dos fenômenos físicos e com base nos estudos teóricos realizados, são feitas sugestões para serem contornadas algumas omissões da Norma. Também são propostas complementação que facilitem o entendimento das novas recomendações e, ainda, modificações que melhorem seus resultados. Sugerem-se métodos simplificados relacionados à punção excêntrica, e propõem-se algumas alterações quanto ao uso do &#947z como coeficiente majorador na avaliação da estabilidade global. Observa-se que as verificações, apesar de mais trabalhosas, apresentam melhorias significativas em relação à NBR 6118 (1978), mostrando-se mais detalhadas e eficientes. Ainda assim, considera-se importante a introdução de algumas complementações, como aquelas sugeridas neste trabalho. / This work presents an overview of the requirements for punching shear and global stability of buildings in the draft Brazilian Code for concrete structures. Suggestions are made for fulfilling some omissions of the Code, based on theoretical studies and physical phenomena analysis. Some complements and changes are also proposed to facilitate the understanding of the new recommendations and to improve their results. Simplified methods related to the eccentric punching and modifications in the use of &#947z as a first order effects magnifier are suggested. It is concluded that the new provisions are more detailed and efficient, presenting significant improvements on both topics, especially when compared to NBR 6118 (1978). Nevertheless, it is considered important the introduction of some complements, as those suggested in this work.

Neste trabalho, são estudas as verificações da punção global segundo a revisão da NBR 6118. A partir da análise dos fenômenos físicos e com base nos estudos teóricos realizados, são feitas sugestões para serem contornadas algumas omissões da Norma. Também são propostas complementação que facilitem o entendimento das novas recomendações e, ainda, modificações que melhorem seus resultados. Sugerem-se métodos simplificados relacionados à punção excêntrica, e propõem-se algumas alterações quanto ao uso do &#947z como coeficiente majorador na avaliação da estabilidade global. Observa-se que as verificações, apesar de mais trabalhosas, apresentam melhorias significativas em relação à NBR 6118 (1978), mostrando-se mais detalhadas e eficientes. Ainda assim, considera-se importante a introdução de algumas complementações, como aquelas sugeridas neste trabalho. / This work presents an overview of the requirements for punching shear and global stability of buildings in the draft Brazilian Code for concrete structures. Suggestions are made for fulfilling some omissions of the Code, based on theoretical studies and physical phenomena analysis. Some complements and changes are also proposed to facilitate the understanding of the new recommendations and to improve their results. Simplified methods related to the eccentric punching and modifications in the use of &#947z as a first order effects magnifier are suggested. It is concluded that the new provisions are more detailed and efficient, presenting significant improvements on both topics, especially when compared to NBR 6118 (1978). Nevertheless, it is considered important the introduction of some complements, as those suggested in this work.