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Steel Portal Frame EC3 RUNET software
13.5.3 Seismic load Eurocode 8-1:2004
The program performs a verification of the structure under seismic loading, using both Lateral force method, and Modal superposition spectrum analysis.
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Basic value used in the seismic design is the ratio of horizontal seismic acceleration. Click and a special dialog window appears where you may in detail specify all the necessary seismic parameters
(soil factors, spectra periods, behaviour factors, etc..) for the design spectrum, according to
Eurocode 8-1:2004.
13.6 Connections
Apex and eave boltconnections with end plate are designed to resist moment and shear forces.
For the apex and eave connection the end plate
(thickness and steel grade) and bolts (diameter, grade) are the same. The thickness of Apex and eave end plate should be at least as thick as the flange thickness of the rafter and column section. At the base of the haunch, a stiffener is designed to resist the increased compressive forces.
Base plate bolt-connection is designed for the column over the concrete foundation. The anchor bolts are designed to resist shear and pullout forces due to uplift wind or seismic forces. CEN/TS 1992-4-1:1992 and CEN/TS 1992-4-2:1992 are used for the design of the fastenings in concrete .
The holding down anchor bolts of the base plate are extended with anchors. The anchor system can be ( simple hook, bended hook or washer plate ) . The hook type anchoring (first two choices) cannot be selected for bolt grade with fy>300N/mm2 (M>5.6), according to
Eurocode 1993-1-8:2005, 6.2.6.12 (6).
The program will, if it is necessary, increase the diameter of the bolts or the thickness of the connection plate to satisfy the design checks. Connections are designed according to EN1993-
1-8.
13.7 Foundation
The concrete footing has to be designed to resist soil pressure for maximum vertical load, and it must have enough weight to resist uplift (from wind or seismic forces).
Reinforced concrete properties
Click and select concrete and steel class. Click to select concrete cover Cnom
[mm]
Fundament dimensions Specify the dimensions of the short column above the fundament cross-section dimensions cx and cy and height ch, and next the diameter of the column main reinforcing bars for the CAD drawing.
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