Search results

In 1993, Tsai et al. studied the effect of unbonded materials on the hysteretic behaviour of buckling restrained braces and developed a double steel tube buckling restrained brace[11].
Schematic of steel moment-resisting frame with EDCs: (a) plane layout; (b) elevation layout of EDC frame; (c) details of EDC system; (d) mechanical behaviour of EDC Figure 26.
[14] Guo Y L, “Design Theory of Assembled Buckling-Restrained Braces and Buckling-Restrained Braced Frames”.
[22] Guo Y L, Dong Q L, “Static behaviour of buckling-restrained steel plate shear walls”.
[36] Dusicka P, Iwai R, “Development of linked column frame system for seismic lateral loads”, Proceedings of the SEI Structures Congress, 2007

Under cyclic loading, BRB exhibits stable elastoplastic hysteretic behavior [1] .
Song has compared the seismic behavior of SC-MRF and MRF with BRBs and it shows that the peak and permanent drift of the former systems are less than the latter [9].
Ou, Effect of brace end rotation on the global buckling behavior of pin-connected buckling-restrained braces with end collars, J.
Sause, Post-Tensioned Seismic Resistant Connections for Steel Frames.
Ye, Modeling and parametric study of beam-to-column connection for self-centering steel moment frames, J.

The inelastic behavior of a 17 level reinforced concrete building, for two structural models, is studied: reinforced concrete frames only (A case), and reinforced concrete frames, and K-type steel braces (B case).
The building is designed to avoid that the drifts exceed 0.012 for the same seismic behavior factor level (Q= 3), in agreement with the Mexico City Code.
In this work, the elastic and inelastic seismic behavior results of a 17 level building (occupation: offices, building type: B) located in a soft soil zone in Mexico City, with two different structural alternatives, is presented: A case, only reinforced concrete frames (beams and columns), and B case, with reinforced concrete frames and structural steel braces in K form.
The structural security facing the service limit state (drifts no bigger than 0.012) and failure limit state (seismic behavior factor Q=3) is checked.
A spectral modal dynamic analysis with three-dimensional behavior is applied taking notice of the gravitational loads and second order effects.

An innovative dissipative (INERD Pin) connection system, which was previously developed for seismic resistant X-braced steel frames, was applied to retrofit existing precast industrial buildings designed only for gravity loads.
The INERD Pin connection was first proposed and applied to steel braced structures, providing high ductility and dissipative capacity, [1].
The aims of this study are: (1) the development of numerical models able to represent the seismic behaviour of precast industrial buildings with dissipative connections; (2) the assessment of the effectiveness of such connections for the mitigation of the effects due to earthquakes.
Conclusions This study investigated the effects of the application of a dissipative beam-to-column connection on the seismic behaviour of existing precast industrial buildings.
These effects were more evident in case of severe seismic excitations.

So the frictions devices are installed on RC (Reinforced Concrete) frames to dissipate the seismic energy and relieve RC elements damage.
Gerald, etal[4] study on design method of energy dissipation braced frame structures.
At the same time, target deformability of the beams and columns are obtained by decomposing the structures storey drift.
Displacement based design are on the basis of elastio-plastic spectrum with various damping ratios and force-reduction factor, which take into account structural nonlinear behavior.
Design example In order to demonstrate the applicability of the proposed method, a five-storey RC frame with friction dissipation brace(as shown fig.5).has been designed.

Introduction Concentrically braced steel frames (CBFs) are widely used in seismic areas due to their high stiffness and strength.
In EC 8 there are two design concepts: i) dissipative structural behaviour and ii) low-dissipative structural behaviour.
Conversely, in EC 8, the requirements on cross-section class of braces depend on the ductility class and behaviour factor, q.
Columns in braced bays shall meet the requirements of Class 1 or Class 2 and be designed as beam-columns.
Seismic design of steel special concentrically braced frame systems – A guide for practicing engineers, NIST GCR 13-917-24, 2013, USA

Seismic Design of Buckling-Restrained Braced Frames.
Experimental Performance of Steel Braced Frames Subjected to Bidirectional Loading.
“Buckling-restrained braced frame connection performance.”
[16] Westeneng B, Lee CL, MacRae G (2016): Prevention of gusset plate out-of-plane sway buckling failure in buckling restrained braced frames.
[17] Westeneng B, Lee CL, MacRae G, Jones A. (2017): Out-of-plane buckling behaviour of BRB gusset plate connections.

But there were fewer studies on seismic behaviors.
The test specimen was a 1/3 scale model and consisted of light-weight portal frame, roof bracing system, column bracings, purline, roof boarding, etc.
Overall, the experimental results and ANSYS analytical results coincided well, but the two displacements had a little difference, because the knee brace and roof bracing system increased the stiffness of the whole portal frame.
Seismic behavior of gable frame consisting of tapered members[J].
Experimental research on hysteretic behavior of light-weight steel portal frame [J].

The braced frame system is widely applied in boiler steel frame for its lower cost and more superior working behavior, some vertical bracings between boiler columns need to be dismantled so as to allow new flue ducts to pass through boiler frame.
According to relevant codes, the effects of vertical bracing on boiler frame are as follows [2]: bearing and transferring the horizontal loads; improving the lateral stability of boiler column; it can help to form spatial force system that bracings work together with frame columns and beams and strengthen the integral rigidity of boiler frame.
If the dismantlement of vertical bracings has great influence on the structural behavior of boiler frame, it should take reinforcement measures to ensure the safety.
General engineering situation The thermal power plant was designed by foreign design institute in the 1990s and boiler steel frame adopts the braced frame system in this project.
The dismantled bracings are located in some floors of boiler frame, which affects mainly structural behavior of the floors where they are located.

Also, sub- structuring pseudo-dynamic earthquake response tests are performed on a possible situation of a two-story braced frame upgraded by the proposed bracing system.
The interface between a bracing member and an existing steel frame consists of a tee stub and a vertical stiffening plate, which are both directly bolted to the H-shaped column web.
Fig. 6 shows the results of loading tests on the braced frame specimen.
The behavior of the fictitious old pair of braces is assumed to follow the hysteresis rule illustrated in Fig. 8.
Further studies are needed to clarify these effects.