Response modification factors (R-factor) are used in current seismic building codes to reduce earthquake forces associated with seismic design level to determine force levels. In recent years, many authors have shown great interest in the development of seismic structural systems and several theoretical and experimental studies have been conducted to investigate performance of dampers but littl...

Design and detailing requirements of seismic provisions for concentrically braced frames ~CBF! were specified based on the premise that bracing members with low KL /r and b / t will have superior seismic performance. However, relatively few tests investigate the cyclic behavior of CBF. It is legitimate to question whether the compression member of CBF plays as significant a role as what has bee...

Depending on the tectonic activities, most buildings subject to multiple earthquakes, while a single design earthquake is suggested in most seismic design codes. Perhaps, the lack of easy assessment to second shock information and sometimes use of inappropriate methods in estimating these features cause successive earthquakes mainly were ignored in the analysis procedure. In order to overcome t...

The Behavior of conventional braced frames, are not the same in tension and compression. This problem can be improved by prevention of buckling under compressive loads, which is called buckling restrained brace(BRB). In this field TTD metal damper also have much attention due to simplicity in construction and execution. This damper is recommended because of accessing to better performance than ...

The knee bracing steel frame (KBF) is a new type of energy dissipating frame which enjoys exceptional ductility and lateral stiffness. Rather than the beam-column joint, one end of the diagonal brace in KBF is attached to the knee element. Indeed, the knee element as a hysteretic damper is designed and detailed to behave like a structural fuse by sustaining controlled inelastic deformations as ...