Earthquake Resistant Behavior Of Tapered Portal Frame

Because of its many advantages, the tapered portal frame is getting more and more application. ((Technology Code of Light Steel Structure of Portal Frame)) (CECS 102:2002), our country enacted, doesn't define conditions that tapered portal frame needs anti-earthquak-e design. But mentions in illustration of rules: when earthquake fortification intensity is 7 degree, the portal frame doesn't need anti-earthquake checking generally; but for 8 degree and above, horizontal just with lengthways frames both need anti-earthquake checking. By calculating large quantity of examples, this text studies earthquake resistant behavior of tapered portal frame with pined bases and analyzes its natural frequency, natural period of vibration and vibration mode. By comparing interior forces of pillar top, beam end and span midpoint in two conditions that seismic action effect participates combination of forces and not when portal frame isn't changed, ensure conditions that combination of seismic action effect has controlling function during tapered portal frame design, and tapered portal frame demands anti-earthquake design.