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RESUMODiante do amplo cenário de crescimento do setor da construção civil, novos processos construtivos estão sendo empregados para obras de pequeno e médio porte, como é o caso de sistemas formados por painéis duplos treliçados pré-moldados de concreto preenchidos com concreto moldado no local. Este artigo buscou investigar analiticamente e experimentalmente, os fatores que interferem na resistência a tensão de cisalhamento da interface entre concretos moldados em diferentes idades. O programa experimental consistiu no ensaio de vinte e seis modelos submetidos a tensão de cisalhamento direto com a espessura do concreto de preenchimento variando de sete, nove e treze centímetros, possuindo interfaces lisas e rugosas além, de diferentes resistências à compressão do concreto de preenchimento. Os resultados do estudo do comportamento dos modelos sob cisalhamento direto mostraram que a presença da armadura que cruza a interface, a resistência à compressão dos concretos envolvidos, a rugosidade e a menor relação entre a espessura da região de preenchimento de concreto e da região de concreto pré-moldado melhoram o comportamento do elemento estrutural. Em geral, os modelos de interfaces lisas deslizaram na ordem de 10 -2 mm, enquanto os modelos de superfícies rugosas ficaram na ordem de 10 -3 mm. Palavras-chaves: painéis duplos treliçados, cisalhamento direto, rugosidade, transferência de esforços de cisalhamento ABSTRACT Due the scenario in the civil construction industry, new constructive processes are being used for construction of small and medium size structures, as is the case of systems formed by double precast concrete panels lattice filled with concrete cast in place. This study aimed to investigate analitically and experimentally, the factors that affected the shear strength on the interface between concrete cast at different ages. In experimental program was tested 26 models subject to a direct shear taking into account different thickness of concrete filling as 7 cm, 9 cm and 13 cm, with smooth and rough interfaces, as well as different the concrete of compressive strength. The models results under direct shear showed that the reinforcement amount which crosses the interface, the concrete compressive strength, the interface surface and a lowest ratio between the thickness of the filling region of concrete and precast concrete improves the behavior of the structural element. In general, the models with smooth interface slided in the order of 10 -2 mm while the rough surfaces models were in the order of 10 -3 mm.

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An experimental and numerical investigation was conducted into the factors that interfere in the shear strength of the concrete-concrete interface in structures composed of double lattice panels subjected to direct shear stress. The experimental program consisted of testing 26 direct shear models with varying widths of concrete filling of 7 cm, 9 cm and 13 cm, with smooth and rough interfaces, as well as different concrete compressive strengths in the filled region. The numerical modeling, which was performed with ANSYS software, employed solid finite elements, bar elements and contact elements, taking into account the non-linearity of the materials involved. The analyses of the experimental results under direct shear indicated that the transfer of stresses at the interface occurred with loss of adhesion. The numerical simulations indicated that the higher the geometric ratio of reinforcement the higher the direct shear strength of the structural model. In general, the slip of the models with smooth interfaces was 2 or 3 times greater than the models with rough surfaces. Numerically, the models with smooth interfaces showed a 36.61% gain in shear strength when the compressive strength in the region filled with concrete increased from 20 MPa to 28.4 MPa.