For increasing performance of frame structure varioustypes of braces are used in frame structure for seismic design. i.e. X-braced, inverted V braced, ZX braced, and Zipper braced frame. Inverted-V-braced frames are one type of ordinary concentrically braced frame. The behaviour of this system is controlled by the buckling of the first story braces in compression, resulting in localization of failure and loss of lateral resistance. To overcome this problem of V-bracing and reduce the unbalance force,for improving seismic behavioura vertical structural member added at the beam mid span from the second stories above, called zipper strut. And this new brace called zipper brace. On zipper brace frame more research has been done by researchers in steel by using different software’s. This paper represents the review on research conducted on zipper braced frame.
The design of earthquake resistant buildings has progressed in recent years. The building has two types frame structure and load bearing structure, in that frame structure is commonly used. Frame structures are the structure which has been made by assembling beam, column and slab at proper position as per requirement to resist the lateral loads and gravity load. Under lateral earthquake loads, simple concrete frames undergo large lateral displacements that may damage structural and non-structural members. Load bearing and frame structures are our traditional structures which we are using sincea years ofconstruction starts for multi storey RCC structures. Most of our building failure studies concluded thatbuildings fail due to formation of diagonal cracks. But using diagonal structural members in frames can increases the capacity of structures against failure. One of the practical ways to prevent these frames undergoing large lateral displacements is to use diagonal members, called brace. A frame in which bracing are used called braced frames. These members increase lateral stiffness of the frame and enhance the capacity of the energy dissipation by plastic deformations. There are various types of braced frame used in steel namely Chevron braced frame, Concentrically Braced Frames (CBF), suspended zipper braced frames, V-brace frame, X- braced frames, XZ- braced frame etc. Adding steel braces enhance greatly the strength capacity of the buildings on the dynamic characteristic of the building the zipper bracing systems are found the most efficient. For seismic analysis of
structures various software, methods were applied in field of structural analysis such as time history analysis, response spectra method, push over analysis. Prakriti Chandrakar et al.  time history analysis is a more precise in description of the structure under dynamic load and it can give a more precise approximation of the interior stresses and also the time and position of the cracks emerging in the structure.
Kadid A et al.  investigated the seismic behaviour of RC buildings strengthened with different types of steel braces, X-braced, inverted V braced, ZX braced, and Zipper braced. NaeimeS  proposes the behaviour of zipper brace frame by using pushover condition. Chuang-sheng Yang  proposes a refined design methodology for zipper braced frames with partial-height zipper mechanisms. Pourbaba M et al. investigated the behaviour of Zipper Braced Frame (ZBF) and compared with Concentrically Braced Frame. Haifeng Yu et al.  proposed that zipper columns are more reasonable design method. Nouri and Imani Kalesarfound out that employing suspended zipper braced frame for rehabilitation and strengtheningof existing structure was economical and practical.Rahimi R et al.  proposes through numerical simulations for lateral capacity and seismic behavior zipper braced frames and suspended zipper braced frames.LuciyaTrica et al.  studied on to apply suitable static method for zipper column design through nonlinear time history analysis. And they investigated the inelastic behaviour
of zipper braced frame in high rise building in high risk seismic
zone (victoriya, BC) under crustal.RazviM proposed that
cable with appropriate pre-stress as a zipper element.
Engineers found Chevron braced frames difficult to design,
since they are not able to distribute unbalanced large forces
because of buckling at bracing system. In order to achieve the
advantages like the effectiveness of stiffness and resistance to
limit the displacement ratio and also ensure the behaviour of the
stability of the structure, concentrically zipper-braced frame is
shaped. ZBF theory was first proposed in 1988 by Khatib. This
system is similar to Chevron system, but only just one additional
element, which was a vertical structural member, connected
at the top and down to the beams at the mid-span point called
strut. This vertical strut named as zipper, and a frame in which
zipper braces were added called zipper brace frame.
Zipper columns are attached vertically and lie perpendicular
(90 degrees) to floor beams. These columns can transfer the
unbalancing force caused by the buckling of the compressive
member of the first-story bracing to the bracings in upper
stories (Figure 1 & 2).
With a proper zipper configuration, it is possible to address
the problems and weaknesses of the chevron bracing frame .
According to the study of Pourbaba P et al.  found that
adding vertical Zipper member had good effects on the behaviour
of the frames. Thus, as it was seen, while the compressive
braced frame members at the first floor was not buckling (at
the beginning of lateral loading), internal force in Zipper braced
member was zero. Bye using the zipper column in CBF reduction
of mid-point deflections of beam in the braced system as well as
improvement of ductility.
By using zipper braces seismic performance improve
significantly than frame without zipper .
Kai Hu, Yimeng Yang  Time history analysis by SAP200
and ETABS are roughly similar. However, SAP2000 does not have
the concept of “storey”, which made the post- processing much
more complicated.Therefore for regular structure ETABS is
recommended.ETABS mainly offers following types of analysis:
(a) Linear (b)Nonlinear (c)Pushover Analysis (d)PΔ Effect
Analysis,and for this analysis ETABS gives good result Rinkesh R
Bhandarkar (Figure 3).
Time history analysis and pushover analysis is used in past
researches.Bill Tremayne time history analysis is more
effective than response spectrum method. Time History is
realistic method, used for seismic analysis, it provides a better
check to the safety of structures analysed and designed by
method specified by IS code Patil AS , Prakriti chandrakar
et al.Time history analysis is a more precise in description of
the structure under dynamic load and it can give a more precise
approximation of the interior stresses and also the time and
position of the cracks emerging in the structure. This method
calculates response of structure subjected to earthquake
excitation at every instant of time (hence the name Time History).
Adding vertical Zipper member had good effects on the
behaviour of the frames. Amount of absorbing energy in
Zipper bracing members is more than Chevron . By using
the zipper strut it leads to better seismic performance of
the structure,by imposing acceleration on the structure and
conducting time history analysis, it is observed that the zipperstrut-
equipped system shows a stronger tendency to form
shear links, leading to greater dissipation capacity in plastic
zoneSeyedMehadiZahrai.Zipper brace improve lateral
strength, ductility, and yielding mechanism than X-bracing
Ashwin PC . Seismic performance of different buildings
in terms of performance point shows that IVF, VBF and ZBF
buildings have higher capacity than other buildings .ZBF
enhances structural performance against seismic load[20,21].
Bracing element will have very important effect on structural
behaviour under earthquake effect . For constant structural
weight, structures designed by using zipper braced frame
experience up to 50% less global ductility ratio(damage)
compared with code-based structuresVaseghiJ .
According to the research the results which were obtained
is most promising technique for seismic rehabilitation  it
is Concluded as in zipper braced frames as number of stories
increases, appeared to account for the increased conservatism of
the procedure as the number of stories increases . according
to the research adding vertical zipper members has good effects
on the behaviour of the frames, also internal forces in zipper is
zero. The use of suspended zipper concept to rehabilitation
and strengthening of structures were economical and practical
. In addition by adding zipper columns to chevron bracing
systems a more uniform interstorey drift distribution over the
building height was observed .