Abstract: The seismic rehabilitation designs of two reinforced
concrete school buildings, representative of a wide stock of similar
edifices designed under earlier editions of the Italian Technical
Standards, are presented in this paper. The mutual retrofit solution
elaborated for the two buildings consists in the incorporation of a
dissipative bracing system including pressurized fluid viscous springdampers
as passive protective devices. The mechanical parameters,
layouts and locations selected for the constituting elements of the
system; the architectural renovation projects developed to properly
incorporate the structural interventions and improve the appearance
of the buildings; highlights of the installation works already
completed in one of the two structures; and a synthesis of the
performance assessment analyses carried out in original and
rehabilitated conditions, are illustrated. The results of the analyses
show a remarkable enhancement of the seismic response capacities of
both structures. This allows reaching the high performance objectives
postulated in the retrofit designs with much lower costs and
architectural intrusion as compared to traditional rehabilitation
interventions designed for the same objectives.
Abstract: The main objective of seismic rehabilitation in the
foundations is decreasing the range of horizontal and vertical
vibrations and omitting high frequencies contents under the seismic
loading. In this regard, the advantages of micropiles network is
utilized. Reduction in vibration range of foundation can be achieved
by using high dynamic rigidness module such as deep foundations. In
addition, natural frequency of pile and soil system increases in regard
to rising of system rigidness. Accordingly, the main strategy is
decreasing of horizontal and vertical seismic vibrations of the
structure. In this case, considering the impact of foundation, pile and
improved soil foundation is a primary concern. Therefore, in this
paper, effective factors are studied on the seismic rehabilitation of
foundations applying network micropiles in sandy soils with
nonlinear reaction.
Abstract: In this paper first, Two buildings have been modeled
and then analyzed using nonlinear static analysis method under two
different conditions in Nonlinear SAP 2000 software. In the first
condition the interaction of soil adjacent to the walls of basement are
ignored while in the second case this interaction have been modeled
using Gap elements of nonlinear SAP2000 software. Finally,
comparing the results of two models, the effects of soil-structure on
period, target point displacement, internal forces, shape deformations
and base shears have been studied. According to the results, this
interaction has always increased the base shear of buildings,
decreased the period of structure and target point displacement, and
often decreased the internal forces and displacements.
Abstract: Chevron frames (Inverted-V-braced frames or Vbraced
frames) have seismic disadvantages, such as not good exhibit force redistribution capability and compression brace buckles
immediately. Researchers developed new design provisions on
increasing both the ductility and lateral resistance of these structures
in seismic areas. One of these new methods is adding zipper columns, as proposed by Khatib et al. (1988) [2]. Zipper columns are
vertical members connecting the intersection points of the braces
above the first floor. In this paper applicability of the suspended
zipper system to Seismic Rehabilitation of Steel Structures is investigated.
The models are 3-, 6-, 9-, and 12-story Inverted-V-braced frames.
In this case, it is assumed that the structures must be rehabilitated. For rehabilitation of structures, zipper column is used. The result of
researches showed that the suspended zipper system is effective in
case of 3-, 6-, and 9-story Inverted-V-braced frames and it would
increase lateral resistance of structure up to life safety level. But in
case of high-rise buildings (such as 12 story frame), it doesn-t show
good performance. For solving this problem, the braced bay can
consist of small “units" over the height of the entire structure, which each of them is a zipper-braced bay with a few stories. By using this
method the lateral resistance of 12 story Inverted-V-braced frames is increased up to safety life level.