figure 3 - etabs general section for non-prismatic beam ... · the inherent sideplate ® connection...
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Pg 1 of 6Structural Design Optimization
CONNECTION STIFFNESS IMPLEMENTATION PROCEDUREFOR ETABS/SAP USERS
Modeling of Lateral Frames Using SidePlate® Connection Technology:
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The inherent SidePlate® connection stiffness can be implemented within ETABS or SAP by replacing the
beam and column stiffness with the SidePlate® stiffness. The SidePlate® connection provides a 100% rigid
panel zone at the column and increases the beam section properties for a distance of approximately the
beam depth (Db) beyond the face of the column. Refer to the SidePlate® Tech Tips document for a
description of the different SidePlate® connection types and general design guidelines.
Figure 1 - SidePlate® Bolted connection elevation Figure 2 - SidePlate® Bolted connection section
BEFORE YOU BEGIN: It is important to ensure that a "Standard Moment Connection" is applied to all lateral
beams before any non-prismatic sections are applied. To remove any RBS or SidePlate® built in features do as
follows: Select all moment frame beams > Assign > Frame > Moment Frame Beam Connection Type > Standard
Moment Connection > OK. Missing this step can result in inaccurate stiffness and/or stress results.
USING NON-PRISMATIC BEAM SECTIONS is the most accurate way of implementing the SidePlate®
connection properties in ETABS or SAP.
The stiffened SidePlate® section extends from column face to Dim A (shown in Figure 1). This stiffened
SidePlate® section, which consists of the physical side plates {A}, cover plates {B} and beam, has an
approximate moment of inertia (3) times that of the beam alone for SMF, IMF and OMF applications and (1)
times the moment of inertia of the beam for R=3 applications.D
b
Column
Beam
C ColL
100% RIGIDPanel Zone
Side plate {A}
Stiffened Region
Column/BeamSeparation
ELEVATION
Dim A
Dim
B
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For more information: Toll Free 800 475 2077 Tel 949 238 8900 www.sideplate.com
Pg 1 of 6Structural Design Optimization
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STEP 1: CREATE THE SECTIONS FOR THE NON-PRISMATIC BEAM (I.E. XXSP) – 1 TOTAL PER
NON-PRISMATIC BEAM (SEE FIG. 3)
Click Define > Section Properties > Frame Sections > choose "Add New Property" > General
Make sure the steel material matches the steel frame members used.
This stiffened SidePlate® section is referred to as the SP section. Change the Section name to
represent the section + SP. (e.g. For W21X62, this section would be called W21X62SP.)
Update the section dimensions:
o Depth = (Dim B) per the SidePlate® Connection Properties document.
o Width = beam width (however does not affect the results, and may be the column width).
Open "Modify/Show Modifiers" and input connection properties per the SidePlate® Connection Properties
document.
Figure 3 - ETABS general section for non-prismatic beam sections
STEP 2: CREATE THE ACTUAL NON-PRISMATIC BEAMS
• Choose "Add New Property" > Nonprismatic
• Change section name to ‘sectionNPSP’ (e.g. W27x102NPSP)
• Change start section and end section to XXSP, which in this
case is the W27X102SP section. Input length = (Dim A) per the
SidePlate® Connection Properties document.
• SP section lengths are set to Absolute type and the beam
section in the middle is set to Proportional type (this accounts for
different bay widths in which this section may be used).
• All EI33 and EI22 Variations are set to Linear type.
Note: SidePlate® developed a tool to help our clients to easily
implement NP sections in ETABS. This tool allows the engineer
to perform Step 1 and Step 2 with a click of a button . Please
contact SidePlate at [email protected] to request this tool. Figure 4 - ETABS non-prismatic sections
For more information: Toll Free 800 475 2077 Tel 949 238 8900 www.sideplate.com
Pg 1 of 6Structural Design Optimization
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STEP 3: MODEL SIDEPLATE ’S PANEL ZONE
• Select all moment frame beams and columns:
• Assign > Frame > End Length Offsets
• Rigid-zone factor = 1.0 > press OK.
(see Fig. 5)
Note: All SidePlate® full-scale steel moment frame testing has
demonstrated that the panel zone contributes very little to the
total overall drift. Thus, it has been deemed by the AISC
CPRP pre-qualification committee that the flexibility in the
panel zone is negligible and can be considered as 100% rigid.
Thus, it would be incorrect to utilize the ETABS Panel Zone
feature when modeling SidePlate®.
STEP 4: CONNECTION WEIGHT
To obtain the approximate connection weight for a specific project, simply email your ETABS model to
[email protected]. One of our engineers will review the model for validation and reply with the
connection weight.
Figure 5 - ETABS end length offsets
IMPORTANT NOTE REGARDING THE SIDEPLATE BUILT IN FEATURE: Due to some recent
modifications in ETABS, it has been discovered that on several isolated instances the software may
incorrectly implement the increased stiffness of the SidePlate connection thus giving inaccurate results.
CSI is aware of the issue and is working diligently to correct this error. For this reason, SidePlate advises
our clients to avoid using the built in feature and to instead utilize non-prismatic beam sections as
described above. Please contact SidePlate® with any additional questions or concerns. CSI apologizes
for this inconvenience and will alert SidePlate as soon as it is fixed.
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