Abstract
Steel connection is utilized to link the beam and column. It moves the plastic hinge structure away at a predetermined distance from the face of the column. To lower the cross-sectional area of the beam flanges, several shape cuts (uniform, radius, taper, and straight cut) are available, and a piece of the beam flanges at the column face is purposefully intended to yield and plastic hinge. The use of a lowered beam section connection reduces stress absorption since the criteria for a strong column–weak beam are met. The ANSYS 14.5 software was used to model four types of reduced beam sections by decreasing the beam flange. In various patterns, fatigue behaviour was studied. The objective of this project is to evaluate the deformations, stresses and transient temperatures deformations, and stresses of the reduced beam section at static structural analysis. In comparison to other connections, steel connection reduced beam section ductile and dissipated energy more. A nonlinear finite element software was used, along with a static study of exhaustion responsiveness transient temperatures. The analysis is carried out to identify the thermal effects on the behaviour of material properties in the elastic and plastic regions. The members with cuts have performed superior in comparison with members without cuts.
1. Introduction
In and near the heat-affected zones, the bolted web-welded flange moment connections in steel moment-resisting frames had unanticipated brittle failures [1]. The Northridge earthquake [2] caused a great deal of damage to people and property. Many industrial steel structures suffered significant damage [3]. Following the Northridge earthquake, many changes have been proposed for new building and steel moment. Many of the suggestions in FEMA 350 [4] have now been incorporated into the Provisions for Structural Steel Buildings of the American Institute of Steel Construction (AISC Seismic) [5]. The welded junction between the bottom flange of a girder and the supporting flange of a column was the most commonly damaged region. All of the steel moment-resisting frames connections that were approved in combined advancements in welding with details caused the beam plastic hinge to form a short distance away from the beam-to-column interface in order for the beam plastic hinge to form a short distance away from the beam-to-column interface. Strengthening details and decreased beam section detailing are the two primary forms of detailing that relocate the plastic hinges away from the connection region [6]. Connections provide a lot of advantages in design practice [7]. When compared to reinforced connections, they do not require continuity plates, panel zone reinforcement, or strong column–weak beam criteria. Due to the poor performance of pre-Northridge moment connections, researchers began to examine the reasons of failure and create new connections for repair, restoration, and new construction [8]. The current investigation could reduce the failure at beam–column connection.
The use of moment-resistant connections in steel constructions has been recommended as a solution by the Federal Emergency Management Agency (FEMA) 350, 351 [9]. Some other reasons why we use RBS is that it reduces stresses and deformation and we can reduce the cost in that particular area of cross-section. Other objective is to construct a connection which is cost-effective. This study helps in the investigation of suitable location of reduced beam section in buildings. The scope is to analyze the steel structure with RBS to that of steel structure without RBS [10]. First, the model is implemented into known computer software ANSYS 14.5 without RBS, and then, it is analyzed by introducing RBS in the model for the investigation of total von Mises stresses, total deformations, and nonlinear finite element software used, along with a static study of exhaustion responsiveness transient temperatures [11]. The analysis is carried out to identify the thermal effects on the behaviour of material properties in the elastic and plastic regions. In addition, severe nonlinear deformation was studied.
2. Geometrical Details of Reduced Beam Section Models
In the structural steel used for this investigation, grades were taken into account. Connections without RBS were labelled as “WRBS,” while connections with RBS were labelled as “RRBS.” The TRBS-to-SRBS connection was built in accordance with AISC and FEMA standards [12]. Geometrical detail of reduced beam section is shown in Figure 1. For both panel zones and continuity plates, the design shear strength, required shear strength, and column web/flange thickness limitations were examined. From the outside, the link was a strong-axis connection [13]. Figure 2 shows the geometrical details of the reduced beam section model. Table 1 provides the material properties of steel section. The column’s height was 194 inches, while the beam’s length from the column’s centre was 156 inches. Table 2 provides the list of the other geometrical details. Table 3 provides that doublers plates and continuity plates are not required when the connection strength is computed using the AISC/FEMA formula.
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3. Results and Discussion
Figure 3 shows the meshed model for the W30 × 283 as a beam and W14 × 283 as a column connection. Figure 3(a) shows the CAD model of steel beam. Figure 3(b) shows RRBS meshing, and the model was constructed with C3D8T field-variable-dependent conductivity elements. Near the junction, the mesh was fine-tuned. For each of the three model instances, a sensitivity analysis was conducted on the mesh size [14]. The final mesh size was 5 mm, which is course meshing. The column was assumed and boundary conditions as both ends are fixed attached, and the joint beam-to-column element connection is totally restrained in Figure 3(c) [15]. Each subassembly is loaded in the displacement control at the beam free end, as detailed in the preceding portion of the analysis research. W14 283 is used as a column and W30 283 is used as a beam in this study. Specimens are taken into account to be free of continuity plates for this research. Figure 4 shows the static structural analysis at 0.05 rad. TRBS static structural, fatigue, and transient thermal analysis is carried out by importing the (Figure 4(a)) CAD model of TRBS utilized in FEM analysis ANSYS 14.5 workbench. From that, the effectiveness of the results on these models is given [16]. The top and bottom of the beam flange reduction of 50% is applied to all connections. Specimens are considered to be free of continuity plates for this research [1]. This was achieved by putting a 100 kN cyclic load on the beam’s flange at a distance and the distance from the support is 147.63 inches [17]. After that, ANSYS was used to execute the static-coupled temperature displacement model by measuring temperatures at various locations of the joint and beam as a function of time [18]. The column’s base was thought to be fixed and joined at both ends [19]. The three cuts performed better compared to other cuts as per literature in seismic analysis.
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This project is to learn about and compare the behaviour of various cut profiles. The von Mises stress diagrams for all connections between 414 MPa (Figure 4(b)) and 703 MPa (Figure 4(c)) are under static structural conditions [20]. For all connections, the stress intensity in the panel zone ranges from 140 MPa to 235 MPa due to flange reduction of 50% applied to all connections, due to flange reduction of area is 55.38 in2. Figure 5 shows the static structural von Mises stress distribution at 0.05 rad. Compared to other RBS, WRBS is the most overall static structural von Mises stress equivalent stress distribution at a static.
The maximum static structural total deformations for all connections are between 29.83 mm and 26.238 mm under static structural conditions shown in Figure 6. Flange reduction of 50% is applied to all connections. Flange reduction of area is 55.38 in2. At a static structural level, in comparison to other RBS, WRBS has the most overall deformations [21]. The value that is displayed next to each colour is static structural total deformations region which is depicted by that particular colour in the model. The blue colour in the model represents the lowest value of the total deformations [22]. Whereas, red colour denotes that the maximum value of the total deformations is 29.83 mm due to flange reduction of 50%. At a static structural level, in comparison to other RBS, WRBS has the most overall deformations.
The value at the temperature 100 centigrade then produces stress distribution. Static structural thermal equivalent (von Mises) stress distribution in TRBS is shown in Figure 7(a) and 810.2 MPa in Figure 7(b). Static structural thermal von Mises stress in SRBS, as shown in Figure 7(c), due to flange reduction of 50%, is applied to all connections due to flange reduction of area is 55.38 in2. The maximum von Mises stress intensity for all connections is 810.2 MPa, as shown in Figure 7(d). Static structural thermal total deformations at 0.05 rad are shown in Figure 8.
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The value at the temperature 100 centigrade then produces the value displayed static structural thermal total deformations region depicted by that particular colour in the model. The blue colour in the model represents the lowest value of the total deformations [23]. Static structural transient thermal maximum total deformation for all connections is 97.028 mm, as shown in Figure 9. Static structural thermal incremental deformations in WRBS and 92.66 mm. Static structural transient thermal total deformations, due to flange reduction of 50%, are applied to all connections, due to flange reduction of area is 55.38 in2.
4. Conclusions
(i)For all connections, the stress intensity in the panel zone ranges from 234.36 MPa to 319.48 MPa at static structural thermal equivalent von Mises stress distribution(ii)At a static structural level, in comparison to other RBS, WRBS has the most overall von Mises stress intensity(iii)The maximum at static structural total deformation for all connections is between 29.83 mm and 26.238 mm under static structural conditions(iv)Static structural transient thermal maximum total deformation for all connections is between 97.028 mm and 92.66 mm(v)For the radius cut RBS, the stress contours are uniform. Stress concentration is seen at the reentrant corners of trapezoidal and straight cut RBS connections, which may ultimately lead to beam flange fracture(vi)For the radius cut RBS, the stress contours are uniform. Stress concentration is seen at the reentrant corners of trapezoidal and straight cut RBS connections, which may ultimately lead to beam flange fractureData Availability
The data used to support the findings of this study are included within the article and are available from the corresponding author upon request.
Conflicts of Interest
The authors declare that there are no conflicts of interest.
Acknowledgments
The authors thank and acknowledge the management of REVA University, Bengaluru, for their support to carry out this research work.