Continuous One-Way RC Slabs with Sinking Outer Support: Tests and Simple Model
Publication: Journal of Structural Engineering
Volume 144, Issue 2
Abstract
Tests were carried out on two continuous one-way slab specimens, representing, at a scale of 1:1.5, the floor slabs of a multistory building most affected by a postulated instant loss of a perimeter column owing to accidental loading. The bottom bars in the first specimen were discontinuous over the central support, and top reinforcement extended only over the supports. In the second specimen, reinforcing bars were continuous from one outer support to the other on both faces of the slab. Thanks to the membrane action due to the horizontal restraint by the rest of the floor system, both specimens—especially the one with continuous top bars—sustained the distributed load of the slab plus a line load along the sinking outer support of without collapse in full scale, with settlement of that support as high as 0.5 m. The main features of the force-deformation behavior can be captured by a simple, hand-calculation model, taking into account geometric nonlinearities, including large deformations. Model predictions compare best with test results when tension stiffening is neglected; moreover, they are not very sensitive to the exact location where the slab first cracks or develops the critical plastic hinge. Test results were combined with those of the perimeter beams on which the slabs are supported to estimate the margin of bearing capacity of these beams over and above self weight, finishings, and quasipermanent loads on the slab. Membrane action in the slab seems to become a prime player in the global response to the loss of a perimeter column when the beam’s flexural mechanism and arch action are past their peak resistance. The slab’s membrane mechanism, together with the arch and catenary actions that develop at the edge beam in the transverse direction when the full structure is considered, are important for maintaining the capacity margin close to its peak value at larger beam deflections. This is better achieved if the slab is reinforced throughout its top surface.
Get full access to this article
View all available purchase options and get full access to this article.
Acknowledgments
The research leading to these results received funding from the General Secretariat for Research and Technology through grant ERC-12 of the Operational Program Education and lifelong learning, cofunded by the European Union (European Social Fund) and national resources.
References
CEB (Comite Euro-Internationale du Beton). (1978). “International system of unified standard codes of practice for structures. 1: Common unified rules for different types of construction and material. 2: CEB-FIP model code for concrete structures.”, Paris.
CEN (European Committee for Standardization). (2004). “Design of concrete structures. 1.1: General rules and rules for buildings.”, Brussels, Belgium.
Dat, P. X., and Hai, T. K. (2013). “Experimental study of beam-slab substructures subjected to a penultimate-internal column loss.” Eng. Struct., 55, 107–115.
Gouverneur, D., Caspeele, R., and Taerwe, L. (2013). “Experimental investigation of the load-displacement behaviour under catenary action in a restrained concrete slab strip.” Eng. Struct., 49, 1007–1016.
Kai, Q., and Li, B. (2012). “Slab effects on response of reinforced concrete substructures after loss of corner column.” ACI Struct. J., 109(6), 845–855.
Kai, Q., and Li, B. (2013a). “Experimental study of drop-panel effects on response of reinforced concrete flat slabs after loss of corner column.” ACI Struct. J., 110(2), 319–329.
Kai, Q., and Li, B. (2013b). “Strengthening and retrofitting of RC flat slabs to mitigate progressive collapse by externally bonded CFRP laminates.” J. Composites Constr., 554–565.
Liu, J., Tian, Y., Orton, S. L., and Said, A. M. (2015a). “Resistance of flat-plate buildings against progressive collapse. I: Modeling of slab-column connections.” J. Struct. Eng., 04015053.
Liu, J., Tian, Y., Orton, S. L., and Said, A. M. (2015b). “Resistance of flat-plate buildings against progressive collapse. II: Modeling of slab-column connections.” J. Struct. Eng., 04015054.
Peng, Z., Orton, S. L., Liu, J., and Tian, Y. (2016). “Effects of in-plane restraint on progression of collapse in flat-plate structures.” J. Perform. Constr. Facil., 04016112.
Stathas, N., Bousias, S. N., Palios, X., Strepelias, E., and Fardis, M. N. (2017). “Tests and simple model of RC frame subassemblies for postulated loss of column.” J. Struct. Eng., 04017195.
Vecchio, F., and Tang, K. (1990). “Membrane action in reinforced concrete slabs.” Can. J. Civil Eng., 17(5), 686–697.
Yi, W. J., Zhang, F.-Z., and Kunnath, S. K. (2014). “Progressive collapse performance of RC flat plate frame structures.” J. Struct. Eng., 04014048.
Information & Authors
Information
Published In
Copyright
©2017 American Society of Civil Engineers.
History
Received: Sep 8, 2016
Accepted: May 11, 2017
Published online: Nov 23, 2017
Published in print: Feb 1, 2018
Discussion open until: Apr 23, 2018
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.