Bispec can be used to calculate linear and nonlinear spectra including "Constant Strength", "Constant Ductility" and "Constant Damage" Nonlinear spectra.
It can be used by Engineers, Students and Researchers to:
Bispec supports 7 different ground motion formats, 10 different hysteretic element models, and more than 60 different spectral values. It provides powerful visualization and plotting tools and allows all data to be exported for further analysis.
Perform 1D & 2D dynamic analysis
Calculate Linear Spectra
Calculate 5 types of nonlinear spectra
10 different linear and nonlinear hysteretic models
Over 60 different spectral quantities
Linear and Nonlinear viscous damping
Why Use bispec?
Easy calculation of Linear and Nonlinear Spectra
Multiple nonlinear hysteretic models: Represent multiple types of structures
Easy Parametric Analysis: Amazing Power for Engineering, Educational and Research Work
Powerful Data Analysis and Export: Visualize data using 2D and 3D Plots and Export all data
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Bispec is a nonlinear spectral analysis software program that performs unidirectional and bidirectional dynamic time-history analysis of a simple dynamic system under earthquake ground motion records. It can also compute several types of Nonlinear Spectra including Constant-Strength, Constant-Ductility and Constant-Damage spectra.
Here are some of Bispec's features:
Time History Analysis Features
Spectral Analysis Features
Force-Deformation Hysteretic Models
The following is the list of 10 hysteretic models available in Bispec. They can be used to model a wide range of structural behavior. See more details on the Nonlinear Hysteretic Models page.
Earthquake Ground Motion Data Formats
Different element models can be used to characterize the hysteretic behavior of the system.
There are 10 different elements that are currently available in Bispec:
1. Elastic Linear Model
2. Bilinear Model with Hardening
3. Bilinear Model with Bidirectional Interaction
4. Clough Bilinear Stiffness Degrading Model
5. Modified Clough Bilinear Stiffness Degrading Model
6. Bilinear Origin-Oriented Model
7. Bilinear Peak-Oriented Model
8. Bilinear Elastic Model
9. Bilinear Flag Model
10. Bilinear Slip Model
Bispec computes a large number of spectral quantities that can be plotted and examined in the Spectral Analysis dialog. They can also be exported to text files for further analysis.
In the spectral analysis window, different spectral values can be selected for plotting along the horizontal or vertical axis. This allows any two spectral quantities to be plotted against each other providing a high degree of freedom for the user to explore alternative data plotting and interpretation forms.
In addition to computed spectral quantities, some of the basic input properties can also be plotted such as period, mass and stiffness. This allows for example plotting any quantity vs. period (T) or stiffness (K).
In general, the available quantities are divided into 5 separate groups of related quantities:
Basic Properties: Period (T), frequency (f), Stiffness (K), Damping Ratio (z ), Mass (M), Hardening Stiffness (Kh), Hardening Stiffness Ratio (Kh/K), Post-yield period (Tsec), P-Delta ratio (P/KL), Damping Coefficient (C), Nonlinear Damping Coefficient (Csup), and nonlinear damping exponent (alpha).
Effective Properties: Effective Period (Teff), Effective Frequency (feff), Effective Stiffness (Keff), Effective Linear Viscous Damping (bIeff), Effective Nonlinear Viscous Damping (bVeff), Total Effective Viscous Damping (bV+Ieff), Effective Hysteretic Damping (bHeff), and Total Effective Damping (bTot_eff).
Kinematics (D, V, A): Sd, Sv, Sar, Sat, PSv, PSa, Dres, Dres/dy, Dres/Sd.
Yielding related quantities: Dyp, Dyn, Gamma (Dinel/Del), Ductility, Pos Ductility, Neg Ductility, YE (Yield Events), Pos YE, Neg YE, Collapse.
Forces: Sfs, Sfd, Sfa, Fyp, Fyn, Cy (Fyp/W), R (Fel/Fyp), Cs (Sfs/W), Eta (Fyp/(M*PGA))
Energy and Power: EI, EK, EE, EH, EHnr, ED, PI, PK, PE, PH, PHnr, PD, and DI_BB (damage index).
The following table lists the 61 spectral quantities and sdof properties that are available for plotting in the spectral results dialog. Each quantity is listed with its symbol, description, dimensional form and physical units. Highlighted text indicates recent changes and additions to Bispec. See the Bispec Help Manual (installed with software) for more details.
Symbol |
Description |
Physical Units |
Unit |
Basic Properties |
|||
T |
Period |
T |
s |
f |
Frequency |
F |
Hz |
K |
Stiffness |
F/L |
Kip/in |
Damping % |
Damping |
- |
% |
M |
Mass |
M |
Kip*s2/in |
Kh |
Hardening Stiffness |
F/L |
Kip/in |
Kh/K |
Hardening Stiffness Ratio |
- |
- |
Tsec |
Post-yield period, corresponding to Kh |
T |
s |
P-Delta ratio |
P-Delta Ratio = P/KL , (where L is the effective height) |
- |
- |
C |
Damping Coefficient for Linear Viscous Damping (LVD) |
F.t/L |
Kip.s/in |
Csup |
Damping Coefficient for Nonlinear Viscous Damping (NLVD) |
F.(t/L)α |
Kip.(s/in)α |
Alpha (α) |
Exponent coefficient for Nonlinear Viscoud Damping (NLVD) |
- |
- |
Effective Properties |
|||
Teff |
Effective Period |
T |
s |
feff |
Effective Frequency |
F |
Hz |
Keff |
Effective Stiffness |
F/L |
Kip/in |
βIeff % |
Effective Inherent (Linear) Viscous Damping (LVD) |
- |
% |
βVeff % |
Effective Supplemental (Nonlinear) Viscous Damping (LVD) |
- |
% |
βV+Ieff % |
Total Effective Viscous Damping (LVD+NLVD) |
- |
% |
βHeff % |
Effective Hysteretic Damping |
- |
% |
βTot_eff % |
Total Effective Damping (Hysteretic + Viscous) |
- |
% |
Kinematics (D, V, A) |
|||
Sd |
Spectral Displacement |
L |
in |
Sv |
Spectral Velocity |
L/t |
in/s |
Sar |
Spectral Acceleration (Relative) |
L/t 2 |
in/s 2 |
Sat |
Spectral Acceleration (Absolute) |
L/t 2 |
in/s 2 |
PSv |
Pseudo-Spectral Velocity = Sd*(2 π /T) |
L/t |
in/s |
PSa |
Pseudo-Spectral Acceleration = Sd*(2 π /T) 2 |
L/t 2 |
in/s 2 |
Dres |
Residual Displacement at end of record (Absolute) |
L |
in |
Dres/Dyp |
Residual ductility |
- |
- |
Dres/Sd |
Dres/Sd ratio |
- |
- |
Yielding |
|||
Dyp |
Positive yield displacement |
L |
in |
Dyn |
Negative yield displacement (Signed) |
L |
in |
Gamma (γ) |
Dinel/Del: Ratio of inelastic Sd to elastic Sd |
- |
- |
Ductility |
Peak Ratio inelastic displacement to yield displacement,
|
- |
- |
Pos Ductility |
Positive Ductility (Dmax/Dyp) |
- |
- |
Neg Ductility |
Negative Ductility (Dmin/Dyn) |
- |
- |
YE |
Number of yielding events |
- |
- |
Pos YE |
Number of positive yield events |
- |
- |
Neg YE |
Number of negative yield events |
- |
- |
Collapse |
Collapse indicator (1: Collapse, 0: No Collapse) |
- |
- |
Forces |
|||
Sfs |
Hysteretic Force = max(fs) |
F |
Kip |
Sfd |
Damping Force = max(fd) |
F |
Kip |
Sfa |
Inertia Force = M*Sat, also equal to max(fs+fd) |
F |
Kip |
Fyp |
Positive yield force |
F |
Kip |
Fyn |
Negative yield force, (Signed) |
F |
Kip |
Cy (Fyp/W) |
Normalized Yield Capacity |
- |
- |
R |
Fel/Fyp: Ratio of elastic Sfs to Fyp |
- |
- |
Cs (Sfs/W) |
Normalized Peak Force |
- |
- |
Eta (η) |
Normalized yield strength = Fyp/(M*PGA) |
- |
- |
Energy & Power |
|||
EI |
Input Energy |
F.L |
Kip.in |
EK |
Kinetic Energy |
F.L |
Kip.in |
EE |
Elastic Energy |
F.L |
Kip.in |
EH |
Hysteretic Energy |
F.L |
Kip.in |
EHnr |
Hysteretic Non-Recoverable Energy |
F.L |
Kip.in |
ED |
Damping Energy |
F.L |
Kip.in |
PI |
Input Power |
F.L/t |
Kip.in/s |
PK |
Kinetic Power |
F.L/t |
Kip.in/s |
PE |
Elastic Power |
F.L/t |
Kip.in/s |
PH |
Hysteretic Power |
F.L/t |
Kip.in/s |
PHnr |
Hysteretic Non-Recoverable Power |
F.L/t |
Kip.in/s |
PD |
Damping Power |
F.L/t |
Kip.in/s |
DI_BB |
Damage index (Bozorgnia and Bertero) |
- |
- |
Bispec is available in three different editions: Standard, Professional, and Advanced. Please see the description below for the various features supported by each edition.
|
Bispec Student |
Bispec Professional |
Bispec Advanced |
Open/Save Functionality |
Yes |
Yes |
Yes |
Single Dynamic Analysis |
Yes |
Yes |
Yes |
Linear Spectra |
Yes |
Yes |
Yes |
Nonlinear Spectra |
Yes |
Yes |
Yes |
Maximum Number of Records in Spectral Analysis |
7 |
100 |
Unlimited* |
Number of Available Hysteretic Models |
6 |
10 |
10 |
Supported Hysteretic Models |
1. Linear 2. Bilnear 3. 2D Bilinear Coupled 4. Clough 5. Modified Clough 6. Bilinear Elastic |
1. Linear 2. Bilnear 3. 2D Bilinear Coupled 4. Clough 5. Modified Clough 6. Bilinear Elastic 7. Origin-Oriented
8. Peak-Oriented
9. Bilinear Flag
10. Bilinear Slip
|
1. Linear 2. Bilnear 3. 2D Bilinear Coupled 4. Clough 5. Modified Clough 6. Bilinear Elastic 7. Origin-Oriented8. Peak-Oriented 9. Bilinear Flag 10. Bilinear Slip |
Parallel Processing Number of Processors |
4 |
8 |
Unlimited* |
Parametric Analysis Capability |
Good |
Better |
Excellent |
Export Resutls for Processing |
Yes |
Yes |
Yes |
Ground Motion Formats |
7 |
7 |
7 |
Export of Results to Text File |
Yes |
Yes |
Yes |
Export all spectral analysis results to a single file (database-like format) | No | No | Yes |
Constant Strength Spectra |
Yes |
Yes |
Yes |
Constant Normalized Strength Spectra |
Yes |
Yes |
Yes |
Constant R Spectra |
Yes |
Yes |
Yes |
Constant Ductility Spectra |
Yes |
Yes |
Yes |
Constant Damage Spectra |
Yes |
Yes |
Yes |
Bidirectional Spectra (Maximum Rotated Spectra) -Compute Resultant -Compute Resultant Angle -Compute SRSS -Compute Geomean |
Yes Yes No No |
Yes Yes No No |
Yes Yes Yes Yes |
Supported Spectral Quantities |
61 |
61 |
61 |
|
|
|
|
Interactive Hysteretic Model Testing |
5 |
10 |
10 |
P-Delta Effects |
Yes |
Yes |
Yes |
2D & 3D Dispaly of Spectral Results |
Yes |
Yes |
Yes |
Animation of Dynamic Analysis Results |
Yes |
Yes |
Yes |
New Detailed Help Documentation |
Yes |
Yes |
Yes |