The design of concrete walls or columns reinforced by several encased steel profiles, also called 19 hybrid walls, is similar to the one of classical reinforced concrete, although specific features 20 require adequate design approaches. Experimental research and numerical models demonstrated 21 the feasibility and validity of such structural components, but simple and practical design 22 methods are still lacking regarding their shear resistance. The evaluation of longitudinal shear 23 action effects at the steel profile concrete interface is a key aspect: research results have been 24achieved in a more or less recent past for different types of connection but without leading to 25 design conclusions. In this paper, the classical equivalent truss model for reinforced concrete 26 subjected to shear is extended to take into account the contribution of the encased profiles to the 27 shear stiffness and strength. Resulting action effects in the steel profiles, in the concrete and at 28 the steel profile concrete interfaces are established which allows performing design checks for 29 those three components. In particular, it is evidenced that friction is one of the main component 30 of the resistance to longitudinal shear at the steel profile-concrete interface. It can be directly 31 checked since the proposed method clearly identifies the compression stresses at that location. 32The validity of the method is assessed by referring to tests results from experimental campaigns 33 in China and in Europe. Some of these tests were carried out without shear connectors welded to 34 the encased steel profiles allowing however achieving the full bending resistance of the element 35 without any apparent problem related to longitudinal shear, like slippage between concrete and 36 steel profile. For some other tests, failure was observed as a consequence of an insufficient shear 37 connection. A detailed assessment of these results shows that the new design proposal is perfectly 38 consistent with all the experimental observations.

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