This study is devoted to seismic collapse safety analysis of performance based optimally seismic designed steel chevron braced frame structures. An efficient meta-heuristic algorithm namely, center of mass optimization is utilized to achieve the seismic optimization process. The seismic collapse performance of the optimally designed steel chevron braced frames is assessed by performing incremen...

Objectives: To determine if immobilization of the knee at varying degrees of knee flexion will limit the surface electromygraphical (sEMG) activity of hamstring muscles during crutch-assisted ambulation. Methods: Ten healthy participants walked with crutches with the knee maintained at 0°, 30°, 60° and 90° of knee flexion, both with and without a brace. The leg was non-weight bearing for all tr...

This paper proposes a simplified analytical model for seismic response prediction of concentrically braced frames. In the proposed approach, a multistory frame model is reduced to an equivalent shear-building one by performing a static pushover analysis. The conventional shear-building model has been improved by introducing supplementary springs to account for flexural displacements in addition...

BACKGROUND The role of knee bracing in anterior cruciate ligament reconstructions is controversial. HYPOTHESIS Functional bracing will have an effect on subsequent knee injury in skiers with anterior cruciate ligament reconstruction. STUDY DESIGN Cohort study; Level of evidence, 3. METHODS From 1991 to 1997, 11606 skiers at a major destination ski resort underwent preseason knee screening...

This is the second of 2 articles on a 3-year investigation of medial collateral ligament sprains of the knee to assess the effectiveness of prophylactic knee braces in NCAA Division I college football players. Position, string, type of session, and daily brace wear were recorded. The injury rates for braced and unbraced knees were used to create an incidence density ratio. The data were stratif...

response modification factor (r-factor) is one of the seismic design parameters to consider nonlinear performance of building structures during strong earthquake. relying on this, many seismic design codes led to reduce earthquake loads imposed to the structure. the present paper tries to evaluate the r-factors of conventional concentric braced frames (cbfs) and special moment frames (mrfs) in ...

Displacement-based methods are recognized as appropriate approaches to reach the goals of performance-based seismic design method. In the direct displacement-based seismic design method, the seismic yield displacement is applied as one of the important design parameters. In this paper, a new relation is suggested to determine the lateral displacement pattern at first yielding of eccentrically b...

yielding elements (ye) are among those devices that not only help control structural damages, but make better seismic behavior by concentrating the frames in some removable part of the structures. ye are located at the intersection of concentric braced frame (cbf) in a rectangular shape. in this paper, seismic behavior of the frames with ye will be investigated. for this reason, 5 braced steel ...