This research studies the use of outriggers and belt truss system for high-rise composite building subjected to earthquake load, consists of columns (W) and (HP), and beams (W), and central concrete core. Using (SAP2000) in three-dimensional (3D) ana
lysis of building, storey displacements and storey drifts has been compared in four cases:
1. (MWBT): Model without belt truss and outriggers.
2. (MBT2): Model with two belt truss and outriggers at the levels (0.5H, H).
3. (MBT3): Model with three belt truss and outriggers at the levels (0.33H, 0.67H, H).
4. (MBT4): Model with four belt truss and outriggers at the levels (0.25H, 0.5H, 0.75H, H).
Displacements reduction were 41.8%, 67.5%, 75.9%, respectively as compared to a model without any belt truss and outrigger system. So, using outrigger and belt truss system in high-rise buildings increase the stiffness and makes the structural form efficient under lateral load.
The European Standard, the New Zealand Standard, the U.S. Standard, the Syrian Standard and the Iranian Standard define a criterion for selecting ground motion records for time-history analysis by similarity between the seismological signature of ear
thquakes used for the analysis and those earthquakes that are expected to happen at the given location. But these standards follow different methodologies. The New Zealand Standard proposes that the spectrum of each selected record should match the design spectrum over a range of periods related to the fundamental period of the structure investigated. The energy of at least one of these record’s spectra must exceed the energy of the design spectrum. The European Standard recommends that the average spectrum of the selected records should be always higher than 90% of the design spectrum in a defined range of periods, and the value of the average spectrum at period equal zero should be larger than the value of the corresponding design spectrum. The U.S. Standard, also the Syrian and the Iranian Standard; advise that in a defined range of periods, the average spectrum of the selected records should be 40% and higher than the code spectrum.
This study illustrates the differences between selecting approaches, and how these differences affect the resulting ground motion records. Some resulting recommendations for record selecting procedures are presented, and advised to be used in addition to the Syrian Standard recommendations.
A computer program "SigProce" (Signal Processing) has been designed to
evaluate seismic response in sites and buildings by multiple techniques, such as
the H/V method and the reference site method, in simple, easy and efficient
manner. The program
has been written using Fortran language for Windows
XP with Microsoft Developer Studio. It allows applying many methods of signal
processing. So, programming these methods provides us a useful tool in
application and education domains. The processing methods which can be
applied are: calibration, shifting and trending correction, decimation, delete an
interval, data windowing, integration and differentiation, signal rotation,
filtering, convolution/deconvolution, correlation, and smoothing. Furthermore,
the program has many graphical outputs for signals, spectra, spectral ratio,
particle ground motion, polarigram and others.
This research deals with the study of the behavior of piles under the influence of seismic loads through (3D) modeling using FE-Method-program (ABAQUS) with special reference to the most important parameters affecting the displacements and internal f
orces generated in piles. This study has been completed in two phases: the first phase is a case study of the single Pile (reference case), where a study of the behavior of a single pile assigning structure is modeled with a degree of freedom. The parametric study results show that the presence of structure causes the application of a large load in the upper part of the pile resulting from the impact of inertia dominating the kinetic effect. The forces of inertia increases with the increasing mass of structure, and when the frequency of structure nears the frequency of seismic load. The second phase deals with the study of the situation of the group of piles, where the study handles the effect of a number of piles, piles spacing, and locations on the internal force and displacements generated in the piles. The parametric study results have shown for this phase of this research that an increase the number of piles in the group causes a significant increase of internal forces generated at the top of the pile and a slight decrease for those forces in the central part of the pile, that seismic loads are not distributed equally for all piles, and that corner piles are subject to greater loads while mid. Piles are subject to less load.
The phenomenon of impact between the adjacent buildings is one of the most important reasons for collapse of buildings during the
earthquakes for that most of the codes resort to avoid impact by
increasing the distance between adjacent buildings, b
ut on the other hand high cost of land requires us to take advantage of the largest possible area in addition to the difficulty of making the separation architecturally and in particularly for high buildings the separation may offer up to 50 cm.
We tried to have this research one of the studies that discuss the
subject of seismic pounding where we discussed the methods for
modeling the pounding and the most appropriate way to study the impact depending on the program dynamic analysis Ansys
(Autodyn Ver. 11) then chose several cases for study seismic
impact in three-dimensional models to cover most of the study
variables that may affect this phenomenon, and we doer non- linear dynamic analysis for all cases, with applying acceleration function is defined by equation its constants are changing with processing the seismic records data.
After finishing the analysis for all the models we have discussed
changing the transitions and stresses and strains , and studied the
factors affecting the impact , and discussed results of study and
then we have summarizes the recommendations in that we see fit
through this search.
Insuring structural system ductility is a main factor justifying the reduction made on design
earthquake forces. Reinforced concrete shear wall is one of the most important systems used for
earthquake resistance of buildings. In this research, many
factors affecting curvature ductility of
shear wall sections are studied. These factors are reinforcement ratio, reinforcement
distribution (uniform and concentrated), axial force level, section length, and material
properties. Results show that increasing reinforcement ratio, will reduce ductility in case of
uniform reinforced shear walls, but it stays stable in case of concentrated reinforcement. As for
axial force level, curvature ductility becomes lower as axial force increases and almost
diminishes when it becomes more than half ultimate axial force bearing capacity.
