The proposal lateral load pattern for pushover analysis is given in two forms for symmetric concrete buildings: 1-(X/H) 0.5 for low-rise and mid-rise buildings, 2- Sin(ΠX/H) for high-rise buildings. These two forms give more realistic results as compared to conventional load patterns such as triangular and uniform load patterns. The assumed buildings of 4, 8, 12, 16, 20 and 30 story concrete buildings are special moment frame which have been designed according to 2800 standard. Then using conventional load patterns and proposal load patterns, the pushover analysis has been done and results have been compared with the outcomes of nonlinear time history analysis. Results show the accuracy of proposed load pattern in comparing to the load patterns proposed by standards such as FEMA356.
Code:
***************************************
Content of this section is hidden, You must be registered and activate your account to see this content. See this link to read how you can remove this limitation:
Effectiveness of modified pushover analysis procedure for the estimation of seismic demands of buildings subjected to near-fault ground motions having fling step
Author: A. Mortezaei and H. R. Ronagh | Size: 6.3 MB | Format:PDF | Quality:Unspecified | Publisher: Nat. Hazards Earth Syst. Sci | Year: 2013 | pages: 15
Near-fault ground motions with long-period
pulses have been identified as being critical in the design of
structures. These motions, which have caused severe dam-
age in recent disastrous earthquakes, are characterized by a
short-duration impulsive motion that transmits large amounts
of energy into the structures at the beginning of the earth-
quake. In nearly all of the past near-fault earthquakes, signif-
icant higher mode contributions have been evident in build-
ing structures near the fault rupture, resulting in the migra-
tion of dynamic demands (i.e. drifts) from the lower to the
upper stories. Due to this, the static nonlinear pushover anal-
ysis (which utilizes a load pattern proportional to the shape
of the fundamental mode of vibration) may not produce ac-
curate results when used in the analysis of structures sub-
jected to near-fault ground motions. The objective of this pa-
per is to improve the accuracy of the pushover method in
these situations by introducing a new load pattern into the
common pushover procedure. Several pushover analyses are
performed for six existing reinforced concrete buildings that
possess a variety of natural periods. Then, a comparison is
made between the pushover analyses’ results (with four new
load patterns) and those of FEMA (Federal Emergency Man-
agement Agency)-356 with reference to nonlinear dynamic
time-history analyses. The comparison shows that, generally,
the proposed pushover method yields better results than all
FEMA-356 pushover analysis procedures for all investigated
response quantities and is a closer match to the nonlinear
time-history responses. In general, the method is able to re-
produce the essential response features providing a reason-
able measure of the likely contribution of higher modes in all
phases of the response
Code:
***************************************
Content of this section is hidden, You must be registered and activate your account to see this content. See this link to read how you can remove this limitation:
Hi!
Does the old trick of moving time backwards work with demo versions that experies after 30 days?
Im interested in a prigram that still hasnt been cracked and would like to run a demo version 30 day trial (all features available).
Anyone has any experience before I try and start conting time
Due to its simplicity, the structural engineering profession has been using the nonlinear static procedure (NSP) or pushover analysis. Modeling for such analysis requires the determination of the nonlinear properties of each component in the structure, quantified by strength and deformation capacities, which depend on the modeling assumptions. Pushover analysis is carried out for either user-defined nonlinear hinge properties or default-hinge properties, available in some programs based on the FEMA-356 and ATC-40 guidelines. While such documents provide the hinge properties for several ranges of detailing, programs may implement averaged values. The user needs to be careful; the misuse of default-hinge properties may lead to unreasonable displacement capacities for existing structures. This paper studies the possible differences in the results of pushover analysis due to default and user-defined nonlinear component properties. Four- and seven-story buildings are considered to represent low- and medium- rise buildings for this study. Plastic hinge length and transverse reinforcement spacing are assumed to be effective parameters in the user-defined hinge properties. Observations show that plastic hinge length and transverse reinforcement spacing have no influence on the base shear capacity, while these parameters have considerable effects on the displacement capacity of the frames. Comparisons point out that an increase in the amount of transverse reinforcement improves the displacement capacity. Although the capacity curve for the default-hinge model is reasonable for modern code compliant buildings, it may not be suitable for others. Considering that most existing buildings in Turkey and in some other countries do not conform to requirements of modern code detailing, the use of default hinges needs special care. The observations clearly show that the user-defined hinge model is better than the default-hinge model in reflecting nonlinear behavior compatible with the element properties. However, if the default-hinge model is preferred due to simplicity, the user should be aware of what is provided in the program and should avoid the misuse of default-hinge properties.
Code:
***************************************
Content of this section is hidden, You must be registered and activate your account to see this content. See this link to read how you can remove this limitation:
Effect of Lateral Load Patterns in Pushover Analysis
Author: Abhilash R. Biju V. Rahul Leslie | Size: 0.25 MB | Format:PDF | Quality:Unspecified | Publisher: 0th National Conference on Technological Trends (NCTT09) 6-7 Nov 2009 College of Engineering Trivandrum 138 | Year: 2009 | pages: 5
Pushover analysis is a static, nonlinear procedure in
which the magnitude of the structural loading is incrementally
increased in accordance with a certain predefined pattern. With
the increase in the magnitude of the loading, weak links and
failure modes of the structure are found. Static pushover analysis is an attempt by the structural engineering profession to evaluate the real strength of the structure and it promises to be a useful and effective tool for performance based design. The performance point of the structure depends on the lateral load pattern applied,on the structure. Commonly applied load patterns are inverted triangle and uniformly distributed. Then guidelines like FEMA257 & 356 provide guidelines for lateral loads and doing pushover analysis. Here pushover analysis is done a typical RCC structure by applying different lateral load patterns using ETABS and SAP2000. The lateral load patterns used here are uniform load distribution and equivalent lateral force distribution as per FEMA-257, lateral loads from response spectrum analysis as per IS-1893(2002) and the lateral load pattern as per Upper-Bound Pushover analysis method.
Code:
***************************************
Content of this section is hidden, You must be registered and activate your account to see this content. See this link to read how you can remove this limitation:
***************************************
Content of this section is hidden, You must be registered and activate your account to see this content. See this link to read how you can remove this limitation:
Pushover Analysis of Medium Rise Multi-Story RCC Frame With and Without Vertical Irregularity
Author: Mohommed Anwaruddin Md. Akberuddin*, Mohd. Zameeruddin Mohd. Saleemuddin ** | Size: 0.93 MB | Format:PDF | Quality:Unspecified | Publisher: M A M Akberuddin et al. Int. Journal of Engineering Research and Application Vol. 3, Issue pp.540-546 | Year: 5, Sep-Oct 2013, | pages: 7
he performance of a structural system can be evaluated resorting to non-linear static analysis. This involves the
estimation of the structural strength and deformation demands and the comparison with the available capacities
at desired performance levels. This study aims at evaluating and comparing the response of five reinforced concrete building systems by the use of different methodologies namely the ones described by the ATC-40 and the FEMA-273 using nonlinear static procedures, with described acceptance criteria. The methodologies are applied to a 3 storey frames system with and without vertical irregularity, both designed as per the IS 456-2000 and IS 1893-2002 (Part II) in the context of Performance Based Seismic Design procedures. Present study aims towards doing Nonlinear Static Pushover Analysis of G+3 medium rise RCC residential building frame which is to be designed by Conventional Design Methodology. A Nonlinear Static Analysis (Pushover Analysis) had been used to obtain the inelastic deformation capability of frame. It was found that irregularity in elevation of the building reduces the performance level of structure there is also decrease in deformation or displacement of the building.
Code:
***************************************
Content of this section is hidden, You must be registered and activate your account to see this content. See this link to read how you can remove this limitation:
![[Image: info.png]](http://postgen.civilea.com/icon/info.png){kind=icon}
![[Image: download.png]](http://postgen.civilea.com/icon/download.png){kind=icon}
![[Image: 34724488905891966033.png]](https://pic.civilea.com/images/34724488905891966033.png)
![[Image: 9780203974018_p0_v1_s260x420.JPG]](http://img1.imagesbn.com/p/9780203974018_p0_v1_s260x420.JPG)
![[Image: 87853307121974316520.png]](https://pic.civilea.com/images/87853307121974316520.png)
![[Image: 50891524219090987915.png]](https://pic.civilea.com/images/50891524219090987915.png)