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1

Overstrength and ductility factors of XBF structures with pinned and fixed supports

Yahmi Djamal, Branci Taïeb, Bouchaïr Abdelhamid, Fournely Eric

Studia Geotechnica et Mechanica

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2023

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Vol. 45, nr 1

41--54

EN

In today's time, most seismic design codes are based on a linear elastic force-based approach that includes the nonlinear response (ductility and over strength) of the structure through a reduction factor (named behavior factor q in Eurocode 8 [EC8]). However, the use of a prescribed q-factor that is constant for a given structural system may fail in providing structures with the same risk level. This paper focuses on the estimation of actual values of q-factor for X-braced steel frames (XBFs) designed according to the European codes and comparing these values to those suggested in EC8. For this purpose, a nonlinear pushover analysis has been performed. The effects of specific parameters, such as the stories number, the brace slenderness ratio, the local response of structural members, and the support type, are evaluated. The results show that the most important parameter that affects the q-factor is the brace slenderness ratio, while the support type has less effect on this factor. Furthermore, a local strength criterion has been proposed to implicitly ensure that the suggested value of the q-factor is conservative.

2

Seismic behavior of cross-laminated timber panel buildings equipped with traditional and innovative connectors

Latour M., Rizzano G.

Archives of Civil and Mechanical Engineering

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2017

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Vol. 17, no. 2

382--399

EN

The aim of this paper is to analyze the possibility to improve the seismic performance of cross-laminated timber (CLT) panel buildings introducing in the structure dissipative connectors in substitution of the classical hold-downs. In fact, as demonstrated by past experimental tests and numerical analyses, hold-downs exhibit a limited dissipation capacity. The proposed dissipative connector is called XL-stub and applies the concept usually adopted for ADAS devices. In order to prove the effectiveness of the proposed system the results of an experimental program devoted to characterize the force–displacement response under cyclic loads and low fatigue behavior of the XL-stub are presented and compared to the results of cyclic tests of hold-downs with same resistance. Afterwards, the comparison is extended at the level of the building, evaluating the influence of the connection on the seismic performance of the whole CLT panel building. To this scope, a FE model of the three-storey building tested within the SOFIE project is calibrated and multiple transient dynamic analyses are performed both for the building with the classical layout of connections and for the building equipped with XL-stubs. The obtained results are compared and the values of the behavior factor for the two solutions are calculated.

3

Compare the behavior factor of the ultimate resistance of moment frame, plain and perforated steel plate shear walls, and buckling restrained brace as yielding metal damper

Ashrafi H. R., Shahbazian K., Bidmeshki S., Yaghooti S., Beiranvand P.

Advances in Science and Technology. Research Journal

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2016

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Vol. 10, nr 29

1--12

EN

Steel moment frame systems, steel plate shear walls and also buckling restrained brace (BRB) are considered as the most widely used seismic resistant systems of the world. Firstly, in this research, in order to validate the finite element models, the tested sample of steel plate shear walls of 4 floors at the University of Alberta, Canada, and the tested sample of buckling restrained brace at the University of Berkeley California, with the software ABAQUS 6.10-1 were used. Then, the obtained results of the test and analysis have been compared. The confirmed models have been used for the analysis of two-dimensional frame of plain and perforated steel plate shear walls with a regular pattern of positing holes in the screen, buckling restrained brace and moment frame of 4 floors.