Ground Motion Intensity Measures For The Evaluation Of Effects Of Pulse-type Ground Motions On The Response Of Single-layer Reticulated Shells

In recent years,pulse-type ground motions were found in several large earthquakes,causing severe damage to many structures.However,the analysis of structures subjected to pulse-type ground motions was mostly about bridges,and few relevant studies were conducted to single layer reticulated shells.To identify ground motion intensity measures for use in the seismic response prediction of single-layer reticulated shells,several ground motion intensity measures were analyzed and evaluated in terms of correlation,efficiency and sufficiency.The major work and conclusions of this thesis are as follows:?1?Three single-layer spherical reticulated shells with different rise-span ratio and five single-layer cylindrical reticulated shells with different rise-span ratio or length-width ratio were designed.Then modal analysis and harmonic response analysis were conducted to them.Results show that for single-layer spherical reticulated shells subjected to harmonic excitation in the horizontal direction,the center of response region is the first natural frequency;and for those subjected to harmonic excitation in the vertical direction,the center of response region is not a particular natural frequency.For single-layer cylindrical reticulated shells subjected to harmonic excitation in the direction along the span,the center of response region is the first natural frequency;for those subjected to harmonic excitation in the direction along the length,the center of response region is the second natural frequency;and for those subjected to harmonic excitation in the vertical direction,the center of response region is the third natural frequency.?2?Incremental dynamic analysis was conducted to the three single-layer spherical reticulated shells and several ground motion intensity measures were evaluated in terms of correlation,efficiency and sufficiency.Results show that for any particular ground motion intensity measure,the measure along the span has stronger correlation compared with that in the vertical direction;and that values of acceleration response spectrum Sa?T1?and Sa?T₂?are the proper intensity measures for the evaluation of the response of single-layer spherical reticulated shells.?3?Incremental dynamic analysis was conducted to the five single-layer cylindrical reticulated shells and several ground motion intensity measures were evaluated in terms of correlation,efficiency and sufficiency.Results show that for any particular ground motion intensity measure,the measure along the span has stronger correlation compared with that in the vertical direction and the direction along the length;and the value of acceleration response spectrum Sa?T?,the value of velocity response spectrum Sv?T?and the value of displacement response spectrum Sd?T?are the proper intensity measures.When the rise-span ratio or the length-width ratio are large,the basic period T1 should be chosen as the parameter T,otherwise the second or third natural period?T₂ or T₃?of the structure should be chosen as the parameter T.