accurate identification of seismic hazard and the estimation of associated seismic demands are the key components in the performance-based seismic design (pbsd). although nonlinear time history (nth) analysis is the most precise procedure to evaluate the seismic demands of buildings structures, it is relatively complex and time-consuming for routine applications. nonlinear static procedures (ns...

Endurance time (ET) method is a relatively new performance-based earthquake method for structural evaluation and design. In this method, the structure is subjected to a gradually intensifying accelorogram(s) and its performance is assessed based on the maximum time duration that it can meet the specified performance objectives. Using moment-resisting and braced frames which are rehabilitated by...

One of the important issues in the study of steel frames is to find a suitable formulation for semi-rigid connections. In this paper, the explicit stiffness matrix for a two-dimensional beam-column element having end-flexibilities is derived. The effects of the lateral uniformly distributed load on the deflection are considered. Both tensile and compressive axial loads are also taken into accou...

A proper composition of stiffness and ductility parameters is required to obtain a resistant and economic structure. Accordingly, Chevron Knee Braced Frame (CKBF) seems appropriate due to its proper seismic performance. The advantage of this system comes to having the capability of rapid and cheap replacement of chevron knee elements after an earthquake occurs. In this research, response modifi...

the present research is concerned with the determination of ductility, over-strength and response modification factors of coupled steel shear wall frames. three structural models with various numbers of stories, bay width and coupling beam height were analyzed using static pushover and incremental nonlinear dynamic analyses. the ductility, over-strength and response modification factors for the...

in this research optimal reconfiguration strategy of the improved srr reconfigurable mobile robot based on force-angle stability measure has been designed using genetic algorithm. path tracking nonlinear controller which keeps robot’s maximum stability has been designed and simulated in matlab. motion equations of the robot have been derived in parametric form by means of newton- euler, lagrang...

it has been pointed out the static lateral response procedure for a base-isolated structure proposed in international building code (ibc) somewhat overestimates the seismic story force. that is why in the current paper, vertical distribution of base shear over the height of isolated structures considering higher mode effects under near field earthquakes is investigated. nonlinear behavior of is...

   Background: Developmental dysplasia of hip (DDH) is a common childhood disorder, and ultrasonography examination is routinely used for screening purposes. In this study, we aimed to evaluate a modified combined static and dynamic  ultrasound technique for the detection of DDH and to compare with the results of static and dynamic ultrasound techniques.    Methods:In this cross-sectional study...

A new procedure for deriving nonlinear mathematical modeling for a specific class of aerospace hydro - mechanical control valves is presented. The effects of friction on the dynamic behavior of these types of valves along with the experimental verifictions are also given. The modeling approach is based on the combination of the following three tasks: decomposition of the valve into simple speci...