The National Building Code of Canada (NBC) 2020 Article 4.1.8.7 provides a clear procedure for earthquake methods of analysis. The more advanced method, the Dynamic Analysis Procedure in Article 4.1.8.12, should be used for all structure types except those that meet the criteria set forth in 4.1.8.7. The more simplistic method, the Equivalent Static Force Procedure (ESFP) in Article 4.1.8.11, can be used for all other structures.
Plate girder is an economical choice for long spans construction. I-section steel plate girder typically has a deep web to maximize its shear capacity and flange separation, yet thin web to minimize the self-weight. Due to its large height-to-thickness (h/tw) ratio, transverse stiffeners may be required to stiffen the slender web.
With the most recent ACI 318-19 standard, the long-term relationship to determine the concrete shear resistance, Vc, is redefined. With the new method, the member height, the longitudinal reinforcement ratio, and the normal stress now influence the shear strength, Vc. This article describes the shear design updates, and the application is demonstrated with an example.
The optimal scenario in which punching shear design according to ACI 318-19 [1] or CSA A23.3:19 [2] should be utilized is when a slab is experiencing a high concentration of loading or reaction forces occurring at one single node. In RFEM 6, the node in which punching shear is an issue is referred to as a punching shear node. The causes of these high concentration of forces can be introduced by a column, concentrated force, or nodal support. Connecting walls can also cause these concentrated loads at wall ends, corners, and ends of line loads and supports.
In RFEM 6, seismic analysis can be done by using the Modal Analysis and the Response Spectrum Analysis add-ons. Once the spectral analysis has been performed, it is possible to use the Building Model add-on to display story actions, interstory drifts, and forces in shear walls.
The punching shear design, in line with EN 1992-1-1, should be performed for slabs with a concentrated load or reaction. The node where the design of punching shear resistance is performed (that is, where there is a punching problem) is called a node of punching shear. The concentrated load at these nodes can be introduced by columns, concentrated force, or nodal supports. The end of the linear load introduction on slabs is also regarded as a concentrated load and therefore, the shear resistance at wall ends, wall corners, and ends or corners of line loads and line supports should be controlled as well.
RF-CONCRETE Members also includes the design of a shear joint. In order to perform this design, you should select the "Shear joint available" check box in Window 1.6, Shear Joint tab.
An elastic foundation can be applied to a member. Thus, the influence of the soil is usually included in the modeling. Member elastic foundations can only be defined for the "Beam" member type.
Cross-section properties in RFEM and RSTAB include different types of shear areas. This technical article explains the calculation and meaning of various values.
Very small torsional moments in the members to be designed often prevent certain design formats. In order to neglect them and still perform the designs, you can define a limit value in RF‑/STEEL EC3 from which torsional shear stresses are taken into account.
In the case of wall-like load-bearing behavior of the cross-laminated timber plate, special attention must be paid to the shear deformation in the plane of the pane and thus, in particular, to the displaceability of the fasteners.
The support of the cross-laminated timber panel deserves special attention. Usually, a cross‑laminated wall is secured against shearing by means of shear connectors and against lifting forces by means of tie rods.
With the SHAPE‑THIN cross‑section properties software, you can create any thin‑walled cross‑section and use it in RFEM or RSTAB as a member cross‑section. SHAPE‑THIN can give all relevant cross‑section values of any cross‑section for a design and stress analysis.
For uniformly distributed loading according to EN 1992‑1‑1 (Eurocode 2), the design section for the shear reinforcement can be placed at the distance d from the front edge of the support. Thus for the shear reinforcement, the applied shear force is reduced to VEd,red. To analyze the maximum design shear resistance VRd,max, however, the total shear force is applied.
In RF‑/STEEL EC3, you can assign the same input data to several members or sets of members at the same time. The simultaneous assignment of the input data is possible for intermediate supports, effective lengths, nodal supports, member end hinges, and shear panel and rotational restraint.
RFEM 5 allows you to use many different member nonlinearities for designing a model. In the following text, we look at an example of the use of the "slippage" member nonlinearity. The example is a simplified model of a concrete manhole with a square plan view.
The shear force resistance VRd,c without computational shear force reinforcement according to 6.2.2 of EN 1992-1-1 [1] or 10.3.3 of DIN 1045-1 [2] is calculated depending on the longitudinal reinforcement ratio. If the required longitudinal reinforcement from the bending design is used for the calculation of VRd,c, this leads to an underestimation of the shear force resistance without shear reinforcement in the vicinity of the hinged end supports. In contrast to the shear force, the required bending reinforcement decreases in the direction of the support. Furthermore, the actually inserted longitudinal reinforcement usually deviates significantly from the required bending reinforcement in the end support area (for example, in the case of non-staggered beam reinforcement).
This article deals with elements concerning which the cross-section is subjected simultaneously to a bending moment, a shear force, and an axial compressive or tensile force. However, in our example we will not include loading due to shear force.
In this article, we will look at the design of shear connectors of cross‑laminated timber structures that transfer the longitudinal forces of the shear wall to the soil.
The stresses in the cross‑section of the member are calculated in the stress points. These points are set at locations in the cross‑section where extreme values for the stresses due to the loading types can occur in the material.
In cross‑sections created in SHAPE‑THIN, the openings, such as bolt holes, can be modeled by using the elements with zero thickness. The program provides two options for calculating shear stresses in the area of such null elements.
The most recent standard ACI 318‑19 redefines the long-term relation for the determination of the concrete shear resistance Vc. With the new method, the member height, the longitudinal reinforcement ratio, and the normal stress now influence the shear strength, Vc. This article describes the shear design updates, and the application is demonstrated using an example.
The National Building Code of Canada (NBC) 2015 Article 4.1.8.7 provides a clear procedure for earthquake methods of analysis. The more advanced method, the Dynamic Analysis Procedure in Article 4.1.8.12, should be used for all structure types except those that meet the criteria set forth in 4.1.8.7. The more simplistic method, the Equivalent Static Force Procedure (ESFP) in Article 4.1.8.11, can be used for all other structures.
When performing shear force design in RF-CONCRETE Members and CONCRETE, you can reduce the acting shear force Vz according to EN 1992-1-1. The following article describes the reduction of the concentrated loads close to the support and the shear force design at the distance d from the support face for a uniform load.
In RF-PUNCH Pro, you can perform the punching shear design on wall corners and wall ends. The basis for the design is the punching load, which is automatically determined from the RFEM internal forces in the connected surface. Since the surface internal forces from the RFEM calculation may be subject to the influence of singularity locations, this can also have a negative influence on the determined punching load at the wall corner or end. This article describes possible optimization options that you can use to minimize this unfavorable influence.
In RF-PUNCH Pro, enlarged column heads can be arranged at point-supported punching shear points, thus increasing the shear force resistance of a reinforced concrete floor. In the following article, we will show the punching shear design with the optional application of an enlarged column head.
RF-PUNCH Pro performs punching shear design on concentrated load application locations (column connection, nodal support, and nodal load) as well as on wall ends and wall corners.
In current literature, the formulas used to determine internal forces and deformations manually are usually specified without considering the shear deformation. The deformations resulting from shear force are often underestimated in timber construction in particular.