the nonlinear static procedures (nsps) proposed by design codes do not lead to reliable results especially for tall buildings. they generally provide inconsistent estimates of inelastic seismic demands, especially for the top floors due to their inabilities in considering the higher modes effects. in this paper, a new enhanced pushover procedure is proposed which is based on the envelope of the...

the proposal lateral load pattern for pushover analysis is given in two forms for symmetric concrete buildings: 1-(x/h)0.5 for low-rise and mid-rise buildings, 2- sin(πx/h) for high-rise buildings. these two forms give more realistic results as compared to conventional load patterns such as triangular and uniform load patterns. the assumed buildings of 4, 8, 12, 16, 20 and 30 story concrete bui...

In this study, constant-ductility optimization algorithm under a family of earthquake ground motions is utilized to achieve uniform damage distribution over the height of steel moment resisting frames (SMRFs). SMRF structures with stiffness-degrading hysteric behavior are modeled as single-bay generic frame in which the plastic hinge is confined only at the beam ends and the bottom of the first...

The proposal lateral load pattern for pushover analysis is given in two forms for symmetric concrete buildings: 1-(X/H)0.5 for low-rise and mid-rise buildings, 2- Sin(ΠX/H) for high-rise buildings. These two forms give more realistic results as compared to conventional load patterns such as triangular and uniform load patterns. The assumed buildings of 4, 8, 12, 16, 20 and 30 story concrete bui...

A review of previous studies shows that there are two general views on how to determine demand in structures through incremental nonlinear static analysis. In the first view, multi-modal methods are used to determine demand in structures. In this view, the applied load pattern is applied to the structure according to the shape of each vibration mode, assuming that the structure deformation foll...

well-known seismic design codes have offered an alternative equivalent static procedure for practical purposes instead of verifying design trials with complicated step-y-step dynamic analyses. such a pattern of base-shear distribution over the building height will enforce its special stiffness and strength distribution which is not necessarily best suited for seismic design. the present study, ...

In the present study, ten steel-moment resisting frames (SMRFs) having different numbers of stories ranging from 3 to 20 stories and fundamental periods of vibration ranging from 0.3 to 3.0 second were optimized subjected to a set of earthquake ground motions using the concept of uniform damage distribution along the height of the structures. Based on the step-by-step optimization algorithm dev...

abstract lateral intake is a hydraulic structure which is used for diversion of some portion of water from a river for the purpose of irrigation, storage and industrial. most of lateral intakes from canal are installed at canal with inclined banks which has not received the attention of the researchers in the past. since the flow discharge and sediment which enters the intake canal depends on t...

Buckling analysis of thin cylindrical shells is very important due to their production process.  Usually longitudinal and transversal stiffeners are used to increase the buckling stiffness. In this paper, considering a thin cylindrical shell with longitudinal and transversal ribs subjected to axial force and lateral pressure, the influence of different aspect of axial force to lateral pressure ...