**SAP2000 is a structural analysis and design software produced by Computer and Structures, Incorporated (CSI), a structural and earthquake engineering company.**

**SAP2000 is a general purpose finite element program which performs the static or dynamic, linear or nonlinear analysis of structural systems. It is also a powerful design tool to design structures following AASHTO specifications, ACI and AISC building codes.**

SAP2000 is a full featured program that can be used for the simplest problems or the most complex projects. It features powerful graphical user interface that is unmatched in terms of ease-of-use and productivity.

Load Cases

• Defines how load are to be applied on the structure and how the structural response is to be calculated

• Classified into two, namely linear and nonlinear, depending on how the structure respond to the load

Linear load

• Static - most common type of analysis, loads are applied without dynamic effect

• Modal - calculation of dynamic mode uses eigenvector or Ritz-vector method,

• Response -Spectrum- statistical calculation caused by acceleration load

• Time-History –time varying load are applied, requires time history function

• Buckling - Calculation of buckling modes under the application of load

• Hyperstatic – calculation of secondary forces due to pre-stressed foces and other self-equilibrating loads

• Moving Loads – calculation of response caused by vehicle loads moving along the paths on the structure

• Multi-Step static – linear static analysis for multi-stepped load cases

• Steady State – harmonically varying load are applied at one or more frequency

• Power Spectral Density - harmonically varying load according to a probalistic specification of loading over a range of frequencies

Nonlinear Load

• Nonlinear Static – loads applied without dynamic effects

• Nonlinear staged construction – loads are applied

without

dynamic effects with portion of the structure being added or removed

• Nonlinear Time-History – time varying load are applied

Function

• Describes how load varies as a function of period or time

• A series of abscissa-ordinate pair

Types

• Response Spectrum Function

• Time-History Function

• Steady-State Function

• Power-Spectral-Density Function

Load Combination

Types

• Linear – results from the included load cases, combos are added linearly

• Absolute – absolute values of the results from the included loads and combos

• SRSS – square root of the sum of the squares of the result from included loads and combos

• Envelope – results from the included load and combos are enveloped to find maximum and minimum values

• Range Add – positive valus are added to the maximum and negative values are added to the minimum value

Output and Display Definition

• Two and three dimensional views

• Tables of values

• Formatted documents containing tables of values in rich text and HTML format

• Function plots of analysis results

• Reports created by using a single command

• Reports customized using an advanced report writing feature

• Exports to other drafting and design programs

Design Setting

• Design features of the program can be used on the frame object whose section properties uses different material

• Several settings can be made that affects the design of a model:

o Specific design code to be used

o Setting on how the codes should be applied

o Combination for which the design should be checked

o Groups of object that should share the same design

o Overwrite function

Groups

A group is a named collection of objects. It may contain any number of

objects of any number of types. Groups have many uses, including:

Quick selection of objects for editing and assigning.

Definition of incremental construction stages.

Definition of section cuts across the model.

Grouping objects that are to share the same design.

Selective output for grouped object.

As many groups as needed can be defined. Using groups is a powerful

way to manage larger models

SAP2000 works with four basics units:

• Force- Kip, Newton

• Length- inches, mm

• Temperature- farenheit, celsius

• Time- seconds

• Mass is usedonly for calculating dynamic inertia and for loads resulting from ground

acceleration.

• Weight is a force that can be applied like any other force

Load. Be sure to use force units when specifying weight values, and mass

units (force-sec2/length) when specifying mass values.

Angular measure always uses the following units:

Geometry, such as axis orientation, is always measured in

degrees

Rotational displacements are always measured in radians

Frequency is always measured in cycles/second (Hz)

Objects and Elements

The physical structural members in the model are represented by objects.

Use the interface to “draw” the geometry of an object, and then “assign”

properties and loads to the object to completely define a model of the

physical member.

The following object types are available, listed in order of geometrical

dimension:

Point objects, of two types:

o Joint objects: Are automatically created at the corners or

ends of all other types of objects, and they can be explicitly

added to model supports or other localized behavior.

o Grounded (one-joint) link objects: Are used to model

special support behavior such as isolators, dampers, gaps,

multi-linear springs, and more.

Line objects, of two types:

o Frame/cable/tendon objects: Are used to model beams,

columns, braces, trusses, cable, and tendon members.

o Connecting (two-joint) link objects: Are used to model

special member behavior such as isolators, dampers, gaps,

multi-linear springs, and more. Unlike frame/cable/tendon

objects, connecting link objects can have zero length.

Area objects: Are used to model walls, floors, and other thinwalled

members, as well as two-dimensional solids (plane stress,

plane strain, and axisymmetric solids).

Solid objects: Are used to model three-dimensional solids.

As a general rule, the geometry of the object should correspond to that of

the physical member. This simplifies the visualization of the model and

helps with the design process

**SAP2000 means Structural Analysis Program2000.**

All locations in the model are ultimately defined with respect to a single

global coordinate system. This is a three-dimensional, right-handed,

Cartesian (rectangular) coordinate system. The three axes, denoted X, Y,

and Z, are mutually perpendicular, and satisfy the right-hand rule.

SAP2000 always considers the global +Z direction as upward. By

default, gravity acts in the –Z direction.

Additional coordinate systems can be defined to aid in developing and

viewing the model. The systems are defined with an origin and

orientation measured with respect to the global system.

For each coordinate system (the global and all additional systems), users

can define a three-dimensional grid system consisting of intersecting

“construction” lines used for locating objects in the model. Each grid

may be of Cartesian (rectangular), cylindrical, or general type.

Drawing operations tend to “snap” to gridline intersections unless this

feature is turned off. The snap feature facilitates accurate construction of

the model. When a grid line is moved, an option can be used to specify

that the points in the model move with it.

Each object in the model (point, line, area, and so forth) has its own local

coordinate system used to define properties, loads, and response for that

object. The axes of each local coordinate system are denoted 1, 2, and 3.

Local coordinate systems do not have an associated grid.

COORDINATE SYSTEM AND GRIDS

Properties are “assigned” to each object to determine the structural

behavior of that object in the model.

Some properties, such as material and section properties, are named

entities that must be defined before assigning them to objects. For

example, a model may have the following properties:

PROPERTIES

A concrete material property called 4000Psi.

A rectangular frame section property called RECT, and a circular

section called CIRC, both using material 4000Psi.

An area section property called SLAB that also uses material

4000Psi.

If a user assigns frame section property RECT to a frame object, any

changes to the definition of section RECT or material 4000Psi will

automatically apply to that object. A named property has no effect on the

model unless it is assigned to an object.

Other properties, such as frame end releases or joint support conditions,

are assigned directly to objects. These properties can only be changed by

making another assignment of that same property to the object; they are

not named entities and they do not exist independently of the objects.