An Analytical Design Method for Steel-Concrete Hybrid Walls

Abstract

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.

08.59: Shear behavior of concrete walls reinforced by multiple steel profiles Calibration of numerical model

“…Consequently it can be consider that the design method [6] is a viable solution to estimate the shear capacity of SRC walls. In this case the development of the cracks it is dependent on two major parameters: the crack bandwidth that implies the mesh size and the fracture energy.…”

“…This solution is considered helpful for those situations where the architectural dimensions are restricted and where the use of a high concrete class would not prove to be sufficient. A tentative design method has been elaborated by the authors based on theoretical reasoning and presented in previous papers [5,6].The currently presented experimental campaign tends to fill some gaps in knowledge related to the behavior of SRC walls subjected to shear effects and provide a reference for the calibration of the design method proposed above [7]. There is however no or limited guidance hereabout in Eurocode 4 or similar standards such as AISC 2010, in particular on how to properly calculate their resistance in shear, compression and bending and on which detailing is required to achieve those resistances.…”

The Smartcoco Design Guide for Hybrid Concrete-Steel Structures

“…4. At ULg, 6 cantilever specimens were tested, out of which 4 in bending, and 2 in bending and compression, see The comparison of numerical calculations and experimental results at the two sites provided a set of conclusions [3].…”

Experimental study of the force transfer mechanism in transition zone between composite column and reinforced concrete column

“…In the attempt to target a specific failure mode of the specimens, namely, failure in the connection zone, it was considered necessary to increase the vertical reinforcement ratio up to 4.35% to ensure the bending resistance of the column. Based on the approach presented by the authors [5] showing that a steel profile can be replaced for the bending verification by equivalent rebars, 4 additional ϕ40 are thus placed in the lower part of the columns, as shown in Fig. 1b.…”

“…• sin (5) Considering that, for each of the schemes, a resistant design maximum stress V Rd can be calculated and the design stress can be obtained using Eq. (6).…”