Punching behaviour of RC flat slabs under reversed horizontal cyclic loading,
Almeida, André F. O., Inácio Micael M. G., Lúcio Válter J. G., and Ramos António Pinho
, Engineering Structures, Volume 117, p.204–219, (2016)
AbstractThe aim of this work is to study the behaviour of reinforced concrete flat slab structures under combined vertical and horizontal cyclic loading. A total of five specimens were cast and tested: a control specimen was punched without eccentricity, one specimen was tested under constant vertical loading and monotonically increased eccentricity until failure and the remaining three were tested under constant vertical load, at different shear ratios, and cyclic horizontal loading with increasing horizontal drift ratios. All slabs were similar, measuring 4.25×1.85×0.15m3. The reinforced concrete slab specimens were connected to two steel half columns by 0.25×0.25m2 rigid steel plates, prestressed against the slab using steel bolts, to ensure monolithic behaviour. The cyclic tests were performed using an innovative test setup that allows bending moment redistribution, line of inflection mobility, assures equal vertical displacements at the North-South borders and symmetrical shear forces. Results show that cyclic horizontal actions are very harmful to the slab–column connection, resulting in low horizontal drifts and energy dissipation.
Punching of Flat Slabs under Reversed Horizontal Cyclic Loading,
Ramos, António, Marreiros Rui, Almeida André, Isufi Brisid, and Inácio Micael
, ACI Fall Convention 2016, Philadelphia, (2016)
AbstractFlat slab structures are a very common structural solution nowadays, due to their architectural and economic advantages. However, flat slab-column connections may be vulnerable to punching failure, especially in an event of an earthquake, with potentially high human and economic losses. This type of structural solution is adequately covered by design codes and recommendations in North America, due to a large amount of experimental research carried out. In Europe the situation is different, missing specific guidance to flat slab design under earthquake action in most European codes. The ACI 318-14 prescriptive approach to the gravity shear ratio-drift ratio relationship shows good agreement with experimental results. Following a similar approach and, based in a databank containing cyclic horizontally loaded tests of slab-column connections found in literature, proposals are made applicable to EC2 and MC2010.
Punching of high strength concrete flat slabs without shear reinforcement,
Inácio, Micael M. G., Almeida André F. O., Faria Duarte M. V., Lúcio Válter J. G., and Ramos António Pinho
, Engineering Structures, nov, Volume 103, p.275–284, (2015)
AbstractThe experimental research carried out to study the punching behavior of high strength concrete (HSC) flat slabs is reported in the present work. Three flat slab specimens were cast using HSC and another one with normal strength concrete (NSC), to be used as a reference slab. The HSC mix presented a compressive strength of about 130MPa, with a basalt coarse aggregate. The tested specimens were square with 1650mm side and 125mm thickness. The longitudinal reinforcement ratio varied between 0.94{%} and 1.48{%}. The experimental results show that the use of HSC led to a significant load capacity increase when compared with the reference model made with NSC. Furthermore, the experimental results also indicated that as the longitudinal reinforcement ratio increased, the punching capacity also increased. The results obtained in this set of experimental tests and others collected from the literature were compared with the code provisions by EC2, MC2010 and ACI 318-11.
Punching of Strengthened Concrete Flat Slabs—Experimental Analysis and Comparison with Codes,
Duarte, Faria, Micael Inácio, Válter Lúcio, and António Ramos
, Structural Engineering International, may, Volume 22, Number 2, p.202–214, (2012)
Abstract