scholarly journals STUDI PENGARUH REDISTRIBUSI MOMEN TERHADAP DAKTALITAS STRUKTUR

2018 ◽  
Author(s):  
ARMAN SETIAWAN
Keyword(s):  
Structure Analysis ◽  
Plastic Hinge ◽  
Pushover Analysis ◽  
Combined Effect ◽  
Efficient Design ◽  
Concrete Frame ◽  
Regular Frame ◽  
Before And After ◽  
Structure Collapse ◽  
Seismic Forces

The combined effect of gravity loads and seismic forces often results inframe moment patterns that do not allow efficient design of beam andcolumn members. Even in the seismic dominated regular frame, wheregravity load moments are approximately 30% of seismic moments, theresulting combination of gravity and seismic moments results in themaximum negative beam moment being about 2.5 times the maximumpositive moment. In line with load increasing, plastic hinges may occur atother locations along the span and may trigger structure collapse but this is only possible when redistribution moment occurs. The structure analysis used is SAP 2000 Version 10.01 and analysis of non-linear staticpushover using Drain 2DX for evaluation and plastic hinge mechanism.Redistribution moment analysis produces an average moment reduction of30%. This result is later analysed with DRAIN 2DX to calculate non-linearstatic pushover analysis both before and after redistribution moment. Afterthe analysis, it is found that the structure ductility is 2.42 beforeredistribution moment and 3.58 after redistribution moment. The resultproves that this method can be used as an alternative design forreinforced concrete frame.

scholarly journals Effect of position of irregularity in concrete frame on response to seismic forces

BIBECHANA ◽  
2017 ◽  
Vol 15 ◽  
pp. 121-130
Author(s):  
Md. Tariqul Islam ◽  
Md Samdani Azad ◽  
Md. Fahim Atif ◽  
Gazi Md. Sharfaraz Imam Azad
Keyword(s):  
Static Analysis ◽  
Pushover Analysis ◽  
Vertical Direction ◽  
Nonlinear Static Analysis ◽  
Concrete Frames ◽  
Concrete Frame ◽  
Frame Building ◽  
Seismic Force ◽  
Frame Buildings ◽  
Seismic Forces

This paper deals with the irregular profile of concrete frame building along vertical direction comprising of mass discontinuity and overhanging mass. The underlying fact of the paper is the effect of seismic force in concrete frames with different types of irregularities including mass discontinuity and overhanging mass. For each successive model, the position of overhanging mass and mass discontinuity is kept variable to make the study effective. This study delineates the vulnerable effect of mass discontinuity and overhanging mass in concrete frame buildings. To attain the nonlinear property of each element of frame, pushover analysis method along with the equivalent static force method has been adopted for the present study. UBC97 code has been used here for linear static analysis while the parameters for nonlinear static analysis are arrogated from FEMA356 and ATC40. Investigations on different frames exhibit that the location of mass discontinuity and overhanging mass can be a key matter to avoid risks due to earthquake. While considering the design of such frames which have irregularities, designer must think about the position of irregularity. Basically, vulnerability increases in the mass discontinuity if the irregularity is in lower stories. Moreover, vulnerability increases in the overhanging masses if the irregularity is in higher stories.BIBECHANA 15 (2018) 121-130

Performance-Based Pushover Analysis for Reinforced Concrete Frame

2011 ◽  
Vol 255-260 ◽  
pp. 2426-2433
Author(s):  
Hui Zhi Zhang ◽  
Xiu Qin Cui
Keyword(s):  
Reinforced Concrete ◽  
Plastic Hinge ◽  
Pushover Analysis ◽  
Time History ◽  
Bending Moment ◽  
Reinforced Concrete Frame ◽  
Concrete Frame ◽  
History Analysis ◽  
Hinge Bending ◽  
Stable Result

For more reasonable and convenient evaluating structure seismic performance,static elasto-plastic analysis of reinforced concrete frame is presented by pushover with different lateral load distributing modes including uniform distribution, inverted triangle distribution and self-adaption distribution adopted, custom plastic hinge, bending moment-curvity relation and bending moment-axial force correlation of each member section are acquired by Response2000, and time history analysis is used to reinforced concrete frame. It is revealed that the presented method is easy and feasiable, and can generatee stable result.

Base-Isolated Multi-Storey Reinforced Concrete Frame Structure Modal Analysis

2012 ◽  
Vol 204-208 ◽  
pp. 869-871
Author(s):  
Cai Hua Wang ◽  
Hui Jian Li ◽  
Jian Feng Wu
Keyword(s):  
Reinforced Concrete ◽  
Modal Analysis ◽  
Seismic Isolation ◽  
Base Isolation ◽  
Frame Structure ◽  
Reinforced Concrete Frame ◽  
Concrete Frame ◽  
Reinforced Concrete Frame Structure ◽  
Before And After ◽  
Isolation Device

The multi-storey reinforced concrete frame structure used lead rubber pad as the base isolation device. The paper had modal analysis of base-isolated multi-storey reinforced concrete frame structure using the ANSYS software. Comparing the frequency and vibration mode before and after isolation under El-Centro wave, It concluded the leader rubber pad have seismic isolation effect for multi-storey reinforced concrete frame structure .

Investigation of Plastic Hinge Length in Reinforced Concrete Columns on Column Behavior

2017 ◽  
Vol 21 ◽  
pp. 45-49
Author(s):  
Mehmet Kamanli ◽  
Alptug Unal
Keyword(s):  
Reinforced Concrete ◽  
Plastic Hinge ◽  
Pushover Analysis ◽  
Concrete Columns ◽  
Analysis Program ◽  
Reinforced Concrete Buildings ◽  
Reinforced Concrete Columns ◽  
Concrete Buildings ◽  
Horizontal Stability ◽  
Plastic Hinge Length

In reinforced concrete buildings in case of a possible earthquake, the buildings slamp as they lost their horizontal stability because of hinging of column ends. The assumptions for plastic hinge lengths are present during project stage of reinforced concrete buildings. According to Turkish Earthquake Regulations, although plastic hinge length is determined to be 0.5h, it's known that plastic hinge length is determined via various formulas in some other regulations all over the world. In reinforced concrete columns, it's necessary to indicate the effect of plastic hinge length on the column behavior. For this purpose, pushover analysis of 5 column samples having different plastic hinge lengths was performed with non-linear analysis program. As a result of pushover analysis, situations of plastic hinges formed in columns and their load-displacement curves were determined. The graphs and the data were compared and the results were discussed.

Seismic Retrofitting of Rectangular Bridge Columns with Composite Straps

1997 ◽  
Vol 13 (2) ◽  
pp. 281-304 ◽  
Author(s):  
H. Saadatmanesh ◽  
M. R. Ehsani ◽  
L. Jin
Keyword(s):  
Plastic Hinge ◽  
Poor Performance ◽  
High Strength ◽  
Bridge Columns ◽  
Absorption Capacity ◽  
Seismic Retrofitting ◽  
Frp Composites ◽  
Reinforced Polymer ◽  
Seismic Forces ◽  
Reversed Cyclic

Behavior of typical rectangular bridge columns with substandard design details for seismic forces was investigated. The poor performance of this type of column attested to the need for effective and economical seismic upgrading techniques. A method utilizing fiber reinforced polymer (FRP) composites to retrofit existing bridge columns is investigated in this paper. High-strength FRP straps are wrapped around the column in the potential plastic hinge region to increase confinement and to improve the behavior under seismic forces. Five rectangular columns with different reinforcement details were constructed and tested under reversed cyclic loading. Two columns were not retrofitted and were used as control specimens so that their hysteresis response could be compared with those for retrofitted columns. The results of this study indicated that significant improvement in ductility and energy absorption capacity can be achieved as a result of this retrofitting technique.

scholarly journals Shear model with shear-flexure interaction for non-linear analysis of reinforced concrete frame element

2018 ◽  
Vol 192 ◽  
pp. 02003
Author(s):  
Worathep Sae-Long ◽  
Suchart Limkatanyu
Keyword(s):  
Reinforced Concrete ◽  
Interaction Effect ◽  
Plastic Hinge ◽  
Shear Stiffness ◽  
Reinforced Concrete Frame ◽  
Shear Model ◽  
Concrete Frame ◽  
Frame Element ◽  
Proposed Model ◽  
Frame System

This paper presents the shear constitutive model for the reinforced concrete (R/C) frame structures analysis under monotonic and cyclic loading. The proposed model is adopted and modified from Mergos and Koppos model [1] that accounts the shear stiffness degradation effect by the shear-flexure interaction in the plastic hinge region. Firstly, the proposed shear model starts from the primary curve without the damages due to the shear-flexure interaction effect. Then, the shear-flexure interaction effect is taken into consideration at the locations of plastic hinges and this effect leads to the degradation of the shear strength and shear stiffness on the undamaged primary curve that is replaced with the damaged primary curve. To determine the sectional shear stiffness with the shear-flexure interaction, an alternative way of the iterative procedure is proposed here. Finally, a numerical example is used to verify the characteristics and behavior of the R/C frame system and confirm accuracy and computational efficiency of the proposed model among the experimental data.

Pushover Analysis of Base Isolated RC Frame Buildings With Masonry Infills

2019 ◽  
Vol 10 (2) ◽  
pp. 18-31
Author(s):  
Radhikesh Prasad Nanda ◽  
Subhrasmita Majumder
Keyword(s):  
Base Isolation ◽  
Plastic Hinge ◽  
Pushover Analysis ◽  
Base Shear ◽  
Infilled Frame ◽  
Masonry Infills ◽  
Time Period ◽  
Frame Buildings ◽  
Story Drift ◽  
Rc Frame Buildings

In the present article, the performance of base-isolated infilled frames is studied analytically. The seismic performances of four RC buildings, namely RC bare frame without isolator, RC bare frame with isolator, RC infilled frame without isolator, and RC infilled frame with isolator are analysed. The results show a decrease in base shear value and increase in time period due to base isolated buildings, while these parameters are reversely affected due to infills. The decrease in story drift for the base isolated buildings is in phase while considering infill. Also, it can be inferred that plastic hinge formation is greatly affected by the introduction of masonry infill. Hence, relying on base isolation without considering infills may underestimate the seismic performance.

scholarly journals The hunt for efficient, incomplete designs for stepped wedge trials with continuous recruitment and continuous outcome measures

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Richard Hooper ◽  
Jessica Kasza ◽  
Andrew Forbes
Keyword(s):  
Outcome Measures ◽  
Total Sample ◽  
Fixed Number ◽  
Good Precision ◽  
Efficient Design ◽  
Stepped Wedge ◽  
Continuous Outcome ◽  
Incomplete Designs ◽  
Before And After ◽  
Stepped Wedge Trials

Abstract Background We consider the design of stepped wedge trials with continuous recruitment and continuous outcome measures. Suppose we recruit from a fixed number of clusters where eligible participants present continuously, and suppose we have fine control over when each cluster crosses to the intervention. Suppose also that we want to minimise the number of participants, leading us to consider “incomplete” designs (i.e. without full recruitment). How can we schedule recruitment and cross-over at different clusters to recruit efficiently while achieving good precision? Methods The large number of possible designs can make exhaustive searches impractical. Instead we consider an algorithm using iterative improvements to hunt for an efficient design. At each iteration (starting from a complete design) a single participant – the one with the smallest impact on precision – is removed, and small changes preserving total sample size are made until no further improvement in precision can be found. Results Striking patterns emerge. Solutions typically focus recruitment and cross-over on the leading diagonal of the cluster-by-time diagram, but in some scenarios clusters form distinct phases resembling before-and-after designs. Conclusions There is much to be learned about optimal design for incomplete stepped wedge trials. Algorithmic searches could offer a practical approach to trial design in complex settings generally.

Strengthening Research in the Longitudinal Frames of Prefabricated Structures with Viscous Dampers

2013 ◽  
Vol 671-674 ◽  
pp. 782-785
Author(s):  
Bin He ◽  
Jin Lai Pang ◽  
Cheng Qing Liu
Keyword(s):  
Seismic Performance ◽  
Pushover Analysis ◽  
Vertical Direction ◽  
Time History ◽  
Nonlinear Time History Analysis ◽  
Viscous Dampers ◽  
Existing Building ◽  
Concrete Frame ◽  
Uniform Drift ◽  
Nonlinear Time History

For the lack of research in the longitudinal frame of prefabricated structure for its weak lateral stiffness, pushover analysis is conducted to evaluate the seismic performance of a fabricated concrete frame. Based on case study, the strengthening strategies with viscous dampers are analyzed. In view of the undesirable drift distribution and failure mode in the existing building, it is believed that arrangement of dampers should be designed to attain a uniform drift distribution. Based on the nonlinear time history analysis method, the strategy of damper allocation in vertical direction of the structure is investigated .Results indicate that a proper design might be attained based on the property of existing system, leading to a uniform drift distribution and better seismic performance.

Study on the Seismic Performance of Shear Wall Structure with Unidirectional Wall Frames Based on Pushover Analysis

2013 ◽  
Vol 353-356 ◽  
pp. 1976-1980
Author(s):  
Kang Yuan ◽  
Ying Min Li ◽  
Song Bai Zhang
Keyword(s):  
Seismic Performance ◽  
Development Process ◽  
Plastic Hinge ◽  
Pushover Analysis ◽  
Shear Wall ◽  
Wall Structure ◽  
Deformation Characteristics ◽  
Displacement Angle ◽  
Earthquake Action ◽  
Overturning Moment

In the paper, the equation of stiff characteristic coefficient of shear wall structure with unidirectional wall frames was derived, the deformation characteristics of structure with different wall frames ratio and height were analyzed. Through pushover analysis, the seismic performance of structures were evaluated by interlayer displacement angle and plastic hinge development process. Under earthquake action, increase of wall frames ratio will make plastic deformation increase and maximum interlayer displacement floor move down.The bottom of structure is the weak region, the short wall limbs of wall frames are the weak structural vertical members. The research results show that the wall frames bring adverse effects on the structural seismic performance, so the different design meathods should be carried out according to the overturning moment proportion of wall frames.

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