Composite action of precast hollow core slabs with structural topping

Wit Derkowski,

Mateusz Surma


There is no interface reinforcement in composite floors made of HC slabs covered with structural topping. In such structures, the preparation of the top surface of the precast element has a major influence on longitudinal shear strength. The recommendations of various codes concerning the bearing capacity of the non-reinforced joint in concrete composite structures are presented in this paper. The results of the authors’ own computational analysis have been compared with the results of experimental tests carried out by different research institutions. Calculations according to Eurocode 2 underrate the value of the bearing capacity. A much stronger conformity of the results was achieved for the calculations carried out according to previously existing standards or according to information given in Model Code 2010.

Słowa kluczowe: composite action, composite structures, hollow core slab, longitudinal shear, structural topping

[1] ACI 318M-11, Building Code Requirements for Structural Concrete and Comentary, American Concrete Institute, USA 2011.

[2] Ajdukiewicz A. et al., Experimental study on effectiveness of interaction between pretensioned hollow core slabs and concrete topping, ACCE, No. 1, 2008.

[3] Derkowski W., Kreska M., Fire resistance of prestressed hollow core slabs, Proc. of KS2015 Conference, Kraków 2015 (in Polish).

[4] Derkowski W., Surma M., Composite action in prestressed rib and beam floor systems without transverse reinforcement, Materiały Budowlane 11/2011, 1–6 (in Polish).

[5] Djazmati B., Pincheira J.A., Shear stiffness and strength of horizontal construction joints, ACI Structural Journal, Vol. 101, 2004.

[6] Elliot K.S. et al., Bending capacity of precast prestressed hollow core slabs with concrete topping, Malaysian Journal of Civil Engineering, Vol. 20, No. 6, 2008.

[7] EN 1168:2005+A3:2011 Precast concrete products – Hollow core slabs, 2011.

[8] EN 1992-1-1:2008 Eurokod 2: Design of concrete structures – Part 1-1: General rules and rules for buildings, 2008.

[9] fib Bulletin 6, Special design considerations for precast prestressed hollow core floors, fib, Lausanne, Switzerland 2000.

[10] fib Bulletin 65, Model Code for Concrete Structures 2010, fib, Lausanne, Switzerland 2012.

[11] Girhammar U.A., Pajari M., Tests and analysis on shear strength of composite slabs of hollow core units and concrete topping, Malaysian JCE, Vol. 22, 2008.

[12] Gohnert M., Horizontal shear transfer across a roughened surface, Cement & Concrete Composites, Vol. 25, 2003.

[13] Halicka A., Study of stress and strain in contact plane and support zone of composite elements involving the shrinkage and expansive concrete, Wydawnictwa Uczelniane, Lublin 2007 (in Polish).

[14] Hegger J., Görtz S., Nachträglich ergänzte Querschnitt mit horizontal Fuge nach DIN 1045-1, Beton- und Stahlbetonbau 98, Heft 5, 2003.

[15] Jansze W. et al., Structural behavior of prestressed concrete hollow core floors exposed to fire, BIBM, 2014.

[16] Mones R.R., Interfacial strength between prestressed hollow core slabs and cast-inplace concrete toppings, Masters of Science in Civil Engineering, 2012.

[17] Mones R.R., Brena S.F., Autors’ response to discussion on hollow-core slabs with castin- place concrete toppings, PCI Journal, Vol. 59, No. 1, 2014.

[18] Pajari M., Shear capacity of hollow core slabs on flexible supports, VTT Research Notes 1587, Espoo 1994.

[19] PCI Design Handbook, Precast and Prestressed Concrete, USA, 2004 Stitmann A., Ueda T., Shear-strength of precast prestressed hollow core slabs with concrete topping, ACI Structural Journal, Vol. 88, No. 4, 1991.

[20] PN-B-03264:2002 Konstrukcje betonowe, żelbetowe i sprężone. Obliczenia statyczne i projektowanie, PKN, Warszawa 2002.

[21] Randl N., Design recommendations for interface shear transfer in fib Model Code 2010, Structural Concrete 14, 2013, No. 3, 230–241.

[22] Scott N.L., Performance of precast prestressed hollow core slab with composite concrete topping, PCI Journal, No. 2, 1973.

[23] Stitmann A., Ueda T., Shear-strength of precast prestressed hollow core slabs with concrete topping, ACI Structural Journal, Vol. 88, No. 4, 1991.

[24] Walraven J.C., Mercx, W., The bearing capacity of prestressed hollow core, Research Raport, Delft 1983.