Modelling punching shear failure at edge slab-column connections by means of nonlinear joint elements

Design of biaxially loaded external slab column connections

“…Linear order hexahedra elements were used to mesh concrete members, while linear order tetrahedra elements were used for steel loading plates. A gradated mesh similar to [9,18] is used in this paper. Force-control and arc-length methods were used in conjunction with the convergence criteria listed in Table 1.…”

“…In this case, punching failure was assumed to occur when the radial compressive strain in the slab soffit at 0.5d from the column face first reduced to zero. This criterion, which is validated for edge column specimens in [9], is based on the experimental observation [19] that the radial strain in the slab soffit near the column face reduces to zero at or near punching failure. Broms [20] adopts a similar failure criterion in his analytical model for punching failure.…”

“…In the JSPME [8,9], punching failure is modelled with nonlinear joint elements that are placed around a punching control perimeter located at 0.5d from the column face. The main advantage of the JSPME over NLFEA with 3D solid elements is the JSPME's greater computational efficiency which lends itself to accurate nonlinear simulations of large structures.…”

“…in which f 𝑐 ′ (MPa) is the concrete cylinder strength, d g (mm) is the maximum aggregate size and d (mm) is the slab average effective depth and ψ si (radians) is the relative slab-column sector rotation for joint 𝑖 which is extracted along the line of radial contraflexure. More details can be found in [7][8][9]18].…”

“…The paper considers three alternative methods for determining the effect of loading eccentricity on punching resistance calculated with the CSCT. In the first approach, the CSCT is implemented in a Joint Shell Punching Model (JSPME) [7][8][9] which directly accounts for the effect of loading eccentricity within the analysis without the need for ke or manual intervention. In the second approach, the shear resisting perimeter is determined using a modified form [10,11] of shear field analysis [12].…”