Browsing by Subject "Lap splices"

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Autoclaved aerated concrete (AAC) masonry : lap-splice provisions and nominal capacity for interface shear transfer between grout and AAC
(2010-12) Forero Henao, Miguel; Klingner, R. E.; Ghannoum, Wassim M.
Design of autoclaved aerated concrete (AAC) masonry in the United States is currently based on Appendix A of the 2008 Masonry Standards Joint Committee (MSJC) Code. Those provisions include the design of lap splices, and equations for the nominal capacity in interface shear transfer between grout and AAC. The provisions for lap splices are an extension of the provisions for concrete or clay masonry, modified to neglect the contribution of AAC to splice capacity. This thesis describes a testing program aimed at verifying the current provisions using tests of lap splices in grouted AAC masonry. Based on the results of those tests, the provisions are shown to be appropriate. The provisions on interface shear transfer between grout and AAC require that the transferred shear be checked against a nominal capacity based on limited test results. This thesis describes a testing program aimed at verifying and refining this nominal capacity using pullout tests of grout cores in AAC masonry units. Based on the results of those tests, the currently used nominal capacity is shown to be conservative, and a recommendation is made to increase it.
Non-linear modeling parameters for reinforced concrete columns with inadequate lap splices
(2015-05) Al Aawar, Wiam; Ghannoum, Wassim M.; Clayton, Patricia
The Structural Engineering Institute of the American Society of Civil Engineers (ASCE/SEI) publishes a Standard used across the United States and in many countries for Seismic Evaluation and Retrofit of Existing Buildings (ASCE/SEI 41-13). The Standard defines strength capacities of structural members, as well as deformation capacities through Modeling Parameters. The objective of this project was to collect and analyze needed data for updating the existing provisions in the Standard for concrete columns governed by splice failure. A database of 51 tests on columns with lap-spliced longitudinal reinforcement was assembled. Strength and deformation capacities were extracted from the test data and used to evaluate the splice failure triggers of ASCE/SEI 41-13. Deformation capacities of columns sustaining splice failures were extracted as nonlinear Modeling Parameters. The parameters were observed to increase with an increase in transverse reinforcement ratio. Additional trends between Modeling Parameters and various influential factors were also investigated and discussed.