Which types of content do you prefer to study in this channel? Your votes help admins to growth of the channel Contents.
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Professional Tcl Language examples about different structures – 46
👍👍👍👍👍👍👍 53%

New algorithms to develop professional Code-Writing – 25
👍👍👍👍 29%

Video cources about earthquake engineering concepts – 12
👍👍 14%

Discussing about users big wrongs in programming – 4
👍 5%

👥 87 people voted so far. Poll closed.

As i accounted for some details about Self Centering Viscoelastic Dampers (SCVDs) devised by (Karavasilis, Blakeborough et al. 2011) a little while ago, take example 5 for instance:👇👇👇
(Part 1);

wipe ;
# Units: Kips, Inch, Sec ;
model BasicBuilder -ndm 2 -ndf 3; # Define the model builder, ndm = # dimension, ndf = # dofs ;
source DisplayModel2D.tcl; # procedure for displaying a
2D perspective of model
source DisplayPlane.tcl; # procedure for displaying a
plane in a model
####################################
# Define Building Geometry, Nodes, and Constraints
####################################
# define structure-geometry parameters
set NStories 5; # number of stories
set NBays 3; # number of frame bays
set WBay 158; # bay width in Inch
set HStory1 197; # 1st story height in Inch
set HStoryTyp 158; # story height of other stories in Inch
set HBuilding [expr $HStory1 + ($NStories-1)*$HStoryTyp]; # height of building ;
# calculate nodal masses -- lump floor masses at frame nodes
set g 386; # acceleration due to gravity
set Floor2Weight 900; # weight of Floor 2 in Kips
set Floor3Weight 900; # weight of Floor 3 in Kips
set Floor4Weight 900; # weight of Floor 4 in Kips
set Floor5Weight 900; # weight of Floor 5 in Kips
set Floor6Weight 700; # weight of Floor 6 in Kips
set WBuilding [expr $Floor2Weight + $Floor3Weight + $Floor4Weight + $Floor5Weight + $Floor6Weight];# total building weight ;
set NodalMass2 [expr ($Floor2Weight/$g) / (4.0)]; # mass at each node on Floor 2 ;
set NodalMass3 [expr ($Floor3Weight/$g) / (4.0)]; # mass at each node on Floor 3 ;
set NodalMass4 [expr ($Floor4Weight/$g) / (4.0)]; # mass at each node on Floor 4 ;
set NodalMass5 [expr ($Floor5Weight/$g) / (4.0)]; # mass at each node on Floor 5 ;
set NodalMass6 [expr ($Floor6Weight/$g) / (4.0)]; # mass at each node on Floor 6 ;
set Negligible 1e-9; # a very smnumber to avoid problems with zero ;
# define nodes and assign masses to beam-column intersections of frame

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Self Centering Viscoelastic Dampers (SCVDs), (Part 2);


# command: node nodeID xcoord ycoord -mass mass_dof1 mass_dof2 mass_dof3
# nodeID convention#
node 11 0 0;
node 21 160 0;
node 31 320 0;
node 41 480 0;
node 12 0 200 -mass $NodalMass2 $Negligible $Negligible;
node 22 160 200 -mass $NodalMass2 $Negligible $Negligible;
node 32 320 200 -mass $NodalMass2 $Negligible $Negligible;
node 42 480 200 -mass $NodalMass2 $Negligible $Negligible;
node 201 240 200;
node 202 240 200;
.
.
.
.
node 16 0 840 -mass $NodalMass6 $Negligible $Negligible;
node 26 160 840 -mass $NodalMass6 $Negligible $Negligible;
node 36 320 840 -mass $NodalMass6 $Negligible $Negligible;
node 46 480 840 -mass $NodalMass6 $Negligible $Negligible;
node 601 240 840;
node 602 240 840;

# constrain beam-column joints in a floor to have the same lateral displacement using the "equalDOF" command
# command: equalDOF $MasterNodeID $SlaveNodeID $dof1 $dof2...
set dof1 1; # constrain movement in dof 1 (x-direction)
equalDOF 12 22 $dof1; # Floor 2: Pier 1 to Pier 2
equalDOF 12 32 $dof1; # Floor 2: Pier 1 to Pier 3
equalDOF 12 42 $dof1; # Floor 2: Pier 1 to Pier 4
.
.
.
equalDOF 16 26 $dof1; # Floor 6: Pier 1 to Pier 2
equalDOF 16 36 $dof1; # Floor 6: Pier 1 to Pier 3
equalDOF 16 46 $dof1; # Floor 6: Pier 1 to Pier 4

# assign boundary condidtions
# command: fix nodeID dxFixity dyFixity rzFixity
# fixity values: 1 = constrained; 0 = unconstrained
# fix the base of the building;
fix 11 1 1 1;
fix 21 1 1 1;
fix 31 1 1 1;
fix 41 1 1 1;
##################
# Define Section Properties and Elements

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Self Centering Viscoelastic Dampers (SCVDs), (Part 3);

###### Material for Beams&Columns Elements ;

uniaxialMaterial Steel02 77 42.06 29e3 0.020
uniaxialMaterial Elastic 78 5.8e3 0.2

# Columns Story 1&2&3 , W14 x 145
section Fiber 21 {
.
.
}
# Columns Story 4&5 , W14 x 74
section Fiber 22 {
.
.
}
# Beams Story 1 , W21 x 83
section Fiber 23 {
.
.
}
# Beams Story 2&3 , W21 x 73
section Fiber 24 {
.
.
}
# Beams Story 4 , W18 x 60
section Fiber 25 {
.
.
}
# Beams Story 5 , W18 x 50
section Fiber 26 {
.
.
}
# however, it is done here simply for illustrative purposes.
# set up geometric transformations of element
geomTransf Corotational 1; # Corotational transformation

geomTransf PDelta 2; # PDelta transformation

# define nonlinear column elements using "element" command
# command: element nonlinearBeamColumn $eleID $iNode $jNode $numintgrpts
$Sectag $transfTag

# Columns Story 1
element nonlinearBeamColumn 101 11 12 5 21 2;
element nonlinearBeamColumn 102 21 22 5 21 2;
element nonlinearBeamColumn 103 31 32 5 21 2;
element nonlinearBeamColumn 104 41 42 5 21 2;
.
.
# Columns Story 5
element nonlinearBeamColumn 501 15 16 5 22 2;
element nonlinearBeamColumn 502 25 26 5 22 2;
element nonlinearBeamColumn 503 35 36 5 22 2;
element nonlinearBeamColumn 504 45 46 5 22 2;
# define nonlinear beam elements
# Beams Story 1
element nonlinearBeamColumn 1001 12 22 5 23 2;
element nonlinearBeamColumn 1002 22 201 5 23 2;
element zeroLength 1003 201 202 -mat 78 -dir 1;
element nonlinearBeamColumn 1004 202 32 5 23 2;
element nonlinearBeamColumn 1005 32 42 5 23 2;
.
.
# Beams Story 5
element nonlinearBeamColumn 5001 16 26 5 26 2;
element nonlinearBeamColumn 5002 26 601 5 26 2;
element zeroLength 5003 601 602 -mat 78 -dir 1;
element nonlinearBeamColumn 5004 602 36 5 26 2;
element nonlinearBeamColumn 5005 36 46 5 26 2;
element corotTruss 901 21 201 30 77;
element corotTruss 902 31 202 30 77;
element corotTruss 903 22 301 30 77;
element corotTruss 904 32 302 30 77;
element corotTruss 905 23 401 30 77;
element corotTruss 906 33 402 30 77;
element corotTruss 907 24 501 30 77;
element corotTruss 908 34 502 30 77;
element corotTruss 909 25 601 30 77;
element corotTruss 910 35 602 30 77;

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Interface for the EigenvalueAnalysis Class (Was Written by Francis Thomas McKenna), Part 1:
Class EigenvalueAnalysis: public Analysis {
Public:
EigenvalueAnalysis(Domain & theDomain,
ConstraintHandler & theHandler,
Dod_Numberer & theNumberer,
AnalysisModel & theModel,
EigenvalueAlgo & theSolnAlgo,
EigenvalueSOE & theSOE,
EigenvalueSOESolver &theSolver,
EigenvalueIntegrator &theEigenIntegrator);
Virtual EigenvalueAnalysis();

Virtual int domainChanged(void);
Virtual int analyze(void);
Virtual double updateMode(int mode);
};

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Pseudo-Code for the EigenvalueAnalysis Class (Was Written by Francis Thomas McKenna), Part 2:

UpdateMode() Method: This is a method to update the nodal displacements with the values in the eigenvector for a specific mode. This is done by invoking update() on the EigenvalueIntegrator object with the correct eigenvector. The method returns the value of the eigenvalue for the specified mode.

EigenvalueAnalysis::analyze(void){
if (theDomain->hasDomainChanged() == true)
this->domainChanged();
theAlgorithm->solveCurrentStep();
analysisDone = true;
};
EigenvalueAnalysis::updateMode(int mode){
if (analysisDone == false)
this->analyze();
const Vector &ɸ = theSOE->getɸ(mode);
theIntegrator->update(ɸ);
return theSOE->getℷ(mode);
}

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Prof. Lu XZ, Prof. Xie LL, Prof. Guan H, Prof. Huang YL and Prof. Lu X. A;

Congratulations on Your Outstanding Achievement !!!

This work develops a new shear wall element model and associated material constitutive models based on the open source finite element (FE) code OpenSees, in order to perform nonlinear seismic analyses of high-rise RC frame-core tube structures. A series of shear walls, a 141.8-m frame-core tube building and a super-tall building (the Shanghai Tower, with a height of 632 m) are simulated. The rationality and reliability of the proposed element model and analysis method are validated through comparison with the available experimental data as well as the analytical results of a well validated commercial FE code. The research outcome will assist in providing a useful reference and an effective tool for further numerical analysis of the seismic behavior of tall and super-tall buildings.
Two mesh schemes are considered, which results in two models: Model 1 and Model 2. Model 1 is relatively coarse, which has 27220 nodes. The coupling beams and shear walls of Model 1 is subdivided to generate Model 2, which has 81572 nodes. The shear walls and coupling beams are simulated using ShellMITC4 in OpenSees. There are some differences in defining the elastic modulus of concrete in ETABS and OpenSees, which will affect the calculated vibration periods. When we conduct the modal analysis, the elastic modulus of concrete material in OpenSees should be adjusted following the equation:

Ec = 2fc / ε ,

Where Ec is elastic modulus of concrete in ETABS. Through the adjustment, the vibration periods of OpenSees agree well with those of ETABS.

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Prof. Y. Jiang, Prof. A. Silva, Prof. L. Macedo, Prof. J. M. Castro and Prof. R. Monteiro;

Congratulations on Your Outstanding Achievement !!!
Thank you for development of an accurate model for CFST members in OpenSees, and to access the influence of CFST members on the seismic performance of moment-resisting frames.
The use of concrete filled steel tube (CFST) member in construction practice has become widespread over recent decades. Confinement effects, that improve both the strength and ductility of the core material, as well as the constraint offered by the core to the encasing steel tube, which minimizes the influence of local buckling, are some of the advantages of these members. As a consequence, the capacity and seismic performance of structures can be improved by the use of CFST members in detriment of reinforced concrete or steel-only solutions.
Two types of beam-column elements were considered to model CFST members in OpenSees, namely Distributed Plasticity (DP) and Concentrated Plasticity (CP) models.
In order to investigate the bending behaviour of long CFST columns, 16 circular rubberized CFST specimens which, were recently tested at the University of Porto, were used to calibrate the aforementioned models.

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The 2018 NHERI SimCenter Programming Bootcamp will be held July 30 through August 3, 2018, at UC Berkeley’s Richmond Field Station.
The NHERI Computational Modeling and Simulation Center (SimCenter) is hosting a “SimCenter Programming Bootcamp.” The overall goal of the bootcamp is to train NHERI researchers in programming paradigms not covered in traditional civil engineering courseware, but which are needed to advance their capabilities with regard to simulation for natural hazards engineering. The target audience is graduate students, postdocs, and new faculty who are interested in simulating the effects of natural hazards on components, structures, and communities. By the end of the workshop, participants will have a firm grasp of how to build applications that utilize SimCenter products and run on the high-performance computing platform hosted at DesignSafe-CI. During the five-day bootcamp, participants will be instructed by and interact extensively with the SimCenter’s lead development team.
A sampling of course modules to be offered include:
- Programming in C, C++, and FORTRAN
- Developing Applications in C & C++
- Parallel Programming on HPC with MPI
- Web Application Development: UI Design & Qt
- Hands on application development
- Parallel exercises on TACC Stampede (HPC)
Each day’s agenda (8:30am – 5pm) will include instruction, the development of custom capabilities, hands-on coding exercises or roundtables, example applications, accessing HPC resources at NHERI, and discussions on working within NHERI using SimCenter products. Daily homework will be assigned. Refreshments at breaks and lunch will be provided.
An early registration fee ($150) is available until June 22, 2018. After that date, the registration fee increases to $250. Registration closes July 9, 2018 or before if the maximum number of attendees register.
Financial support Limited domestic travel, lodging, and meal support is available for need-based participants. To request financial support, email <NHERI-SimCenter@berkeley.edu> by May 25, 2018. Graduate students, postdocs, and faculty from under-represented groups are especially encouraged to attend.
This workshop is supported by NSF Award Number CMMI-1612843. Learn more about the SimCenter at https://simcenter.designsafe-ci.org
All questions and concerns may be forwarded to NHERI-SimCenter@berkeley.edu

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The probabilistic seismic hazard analysis (PSHA) is composed of the following steps:
1. Identification of all earthquake sources, both faults and areal regions, capable of producing damaging ground motions to a site.
2. Characterization of the distribution of earthquake magnitudes. The cumulative distribution function is computed for the magnitudes of earthquakes that are larger than some minimum magnitude Mmin and smaller than the upper bound of earthquake magnitudes in a region Mmax due to the finite size of the source faults:

FM(m) = P(M ≤ m|Mmin < M < Mmax)

3. Characterization of the distribution of source-to-site distances associated with potential earthquakes. For a given earthquake source, it is assumed that earthquakes will occur with equal probability at any location on the fault.
4. Prediction of the resulting probability distribution of ground motion intensity by a prediction model, as a function of predictor variables such as the earthquake’s magnitude and distance.
5. Combination of uncertainties in earthquake magnitudes, source-to-site distances and ground motion intensity, using the total probability theorem.

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Spectral Shapes of the Records (Professor Laura Eads, Stanford University):

A common method of incorporating spectral shape is to use the ratio of spectral acceleration at a given period to the spectral acceleration at the fundamental period (Sa(T1)), to improve the estimation of peak interstory drift ratios of nonlinear systems.
Spectral shape is an important consideration when choosing which ground motions to use for response history analysis. As demonstrated by previous studies the spectral shape of a record can significantly influence the nonlinear response of a structure; however, the spectral shape can also influence the linear response of a multiple degree of freedom structure when using records scaled to a common Sa(T1) because of higher-mode effects. Design codes often have provisions about the spectral shapes of the records used in response history analysis. For example, ASCE 7-10 (2010) requires that the average spectrum of records used in two-dimensional response history analysis cannot be less than the design spectrum between a period range of 0.2·T1 and 1.5·T1.
Recognizing that spectral shape can play an important role in nonlinear structural response, the Design Ground Motion Library (Power et al. 2007), which contains acceleration histories suitable for response history analysis of various structures in California, evaluates the spectral shape of a potential record on both (1) the mean squared error of spectral ordinates over a period band with respect to a target spectrum and (2) the slope of the record’s spectrum over the period band versus the slope of the target spectrum over the same period band.

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