Steel Buildings in Europe

Part 4: Detailed Design of Portal Frames 4 - 10 M M M y p 1 1 2 3 2  1 True behaviour 2 Elastic-perfectly-plastic model 3 Unloading behaviour Figure 3.4 Moment/rotation behaviour and elastic-perfectly-plastic model for a Class 1 section (4) 2 6 3 5   1 V Ed Ed Ed H H Ed, V (7) 1 Elastic response 2 First hinge forms 3 Second hinge forms 4 Horizontal displacement 5 True behaviour 6 Elastic/perfectly plastic model 7 Increasing vertical and (in proportion) horizontal load Figure 3.5 Simple model of a portal frame subject to increasing vertical and horizontal loads, with failure governed by a sway mechanism