Abstract: The design of high-rise building is more often dictated
by its serviceability rather than strength. Structural Engineers are
always striving to overcome challenge of controlling lateral
deflection and storey drifts as well as self weight of structure
imposed on foundation.
One of the most effective techniques is the use of outrigger and
belt truss system in Composite structures that can astutely solve the
above two issues in High-rise constructions.
This paper investigates deflection control by effective utilisation
of belt truss and outrigger system on a 60-storey composite building
subjected to wind loads. A three dimensional Finite Element Analysis
is performed with one, two and three outrigger levels. The reductions
in lateral deflection are 34%, 42% and 51% respectively as compared
to a model without any outrigger system. There is an appreciable
decline in the storey drifts with the introduction of these stiffer
arrangements.
Abstract: This paper presents a conceptual model of agreement
options for negotiation support in multi-person decision on
optimizing high-rise building columns. The decision is complicated
since many parties involved in choosing a single alternative from a
set of solutions. There are different concern caused by differing
preferences, experiences, and background. Such building columns as
alternatives are referred to as agreement options which are
determined by identifying the possible decision maker group,
followed by determining the optimal solution for each group. The
group in this paper is based on three-decision makers preferences that
are designer, programmer, and construction manager. Decision
techniques applied to determine the relative value of the alternative
solutions for performing the function. Analytical Hierarchy Process
(AHP) was applied for decision process and game theory based agent
system for coalition formation. An n-person cooperative game is
represented by the set of all players. The proposed coalition
formation model enables each agent to select individually its allies or
coalition. It further emphasizes the importance of performance
evaluation in the design process and value-based decision.
Abstract: A lot of computer-based methods have been developed
to assess the evacuation capability (EC) of high-rise buildings.
Because softwares are time-consuming and not proper for on scene
applications, we adopted two methods, fuzzy analytic hierarchy
process (FAHP) and technique for order preference by similarity to an
ideal solution (TOPSIS), for EC assessment of a high-rise building in
Jinan. The EC scores obtained with the two methods and the
evacuation time acquired with Pathfinder 2009 for floors 47-60 of the
building were compared with each other. The results show that FAHP
performs better than TOPSIS for EC assessment of high-rise buildings,
especially in the aspect of dealing with the effect of occupant type and
distance to exit on EC, tackling complex problem with multi-level
structure of criteria, and requiring less amount of computation.
However, both FAHP and TOPSIS failed to appropriately handle the
situation where the exit width changes while occupants are few.
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.
Abstract: We study dynamic instability in high-rise steel moment
resisting frames (SMRFs) subjected to synthetic long-period ground
motions caused by hypothetical huge subduction earthquakes. Since
long duration as well as long dominant periods is a characteristic of
long-period ground motions, interstory drifts may enter the negative
postyield stiffness range many times when high-rise buildings are
subjected to long-period ground motions. Through the case studies of
9 high-rise SMRFs designed in accordance with the Japanese design
practice in 1980s, we demonstrate that drifting, or accumulation of
interstory drifts in one direction, occurs at the lower stories of the
SMRFs, if their natural periods are close to the dominant periods of the
long-period ground motions. The drifting led to residual interstory
drift ratio over 0.01, or to collapse if the design base shear was small.