MIDAS SDS

SDS is a structural analysis and automatic design system for floor plates and foundation mats. It uses the Graphic User Interface proven by Gen for efficiency and versatility. SDS retains utmost quality so far as accuracy and productivity are concerned.

	100% Data conversion is possible between Gen and SDS. This capability results in a dramatic increase in productivity in the analysis and design of floor/mat structures of shear wall type residential buildings.
	SDS supports the Input System in the form of Drag & Drop to ease the modification process of design models.
	Object oriented modeling and automatic finite element generation capabilities enable the user to freely model the structures of complex floor layouts.
	Model Wizard provides various types of pre-defined slabs for convenient modeling.
	SDS automatically calculates the elastic support stiffness of columns, walls, piles and sub-soils beneath foundation.
	Analyses of anisotropic slabs such as metal decks are possible using Skewed Orthotropic Element.
	Using the Mesh Line generation function for each Domain, member forces and reinforcement reflecting the reinforcing directions can be obtained.
	SDS performs serviceability evaluation for floor vibrations due to walking loads. SDS contains several types of walking loads in the database.
	Applying Multi-frontal Solver considerably reduces analysis time.
	Using the reactions of the frame analysis, SDS automatically carries out pile placing and mat design.
	SDS provides Punching Shear Stress Ratios due to direct reactions and reinforcement contours, which are used to examine the shear stresses and required reinforcement.
	Pile placing drawings and slab/mat reinforcing drawings are produced (Upgrade in progress).

SDS adopts the advantages of the Graphic Interface and Menu/Input System of Gen. Accordingly, the Gen user becomes familiar with SDS without additional efforts.
The Model Table, MGT Command Shell function of Text type and On-line Manual function are identically applied. The Works Tree of the Tree Menu identically supports the data revision function via Drag and Drop.

Data Conversion between Gen and SDS plays a significant role for residential projects where overall structural analyses shall be carried out in conjunction with the analyses of floor plates and mat foundations. Residential projects of irregular shear wall layouts become the substantial beneficiaries of this functionality in terms of high productivity.

Gen->SDS (Model Data)
Auto-generation of an analysis model for a floor plate or foundation mat using the Gen model of the total structure

SDS->Gen (Load Data)
Auto-generation of loading data for the total structure using the reactions obtained from floor plate analyses

Gen->SDS (Model+Reaction Data)
Auto-generation of loading data for an SDS model of a foundation mat using the reactions of the Gen model for the total structure

Application of Objects

SDS adopts the notion of Object, which is a step before the generation of nodes and elements. The concept of Object provides the freedom of modeling from the constraints of Mesh Line.

Object	Member	Boundary	Load/Mass
Point		Column Support Pile Support General Spring Punching Check Size	Point Load Specified Displacement Dynamic Point Load Point Mass
Line		Wall Support Beam End Release Beam End Offset	Line Load Line Mass
Area		Soil Support Slab End Release	Area Load Area Mass

Model Wizard
		Model Wizard generates analysis models for floor plates and foundation mats by simple specifications of basic information.
Object Generation
		SDS provides utmost efficiency in plate modeling on the basis of CAD-based Object Generation. Assigned attributes (members, loads, boundary conditions, etc) may be selectively included when copying the Objects. Also, using the Point Object, Line Objects in the horizontal or vertical directions can be generated by the Orthogonal function.

Generation of Mesh Line by Domains

In the case of a residential structure with complex shear wall and building layouts, difficulties arise using the conventional Grid Mesh Line if the layouts deviate from an orthogonal pattern. The global application of Grid Line Mesh permits no flexibility in pile modeling and reinforcement directions. SDS now resolves all these problems for practicing engineers. All you have to do is to simply define the domains of different plan layouts such that Mesh Line is generated for each domain reflecting the reinforcement directions.

Pile layout of a 'kinked' plan

Meshing for each domain

Conventional Grid Mesh

The Domain function allows the user to obtain accurate member forces for reinforcement design. Piles arranged in a number of specific directions can be defined by flexible user-defined coordinate systems for the total plate analysis.

Boundary Condition
		SDS automatically calculates the elastic support stiffness of columns or walls supporting a slab and uses the data for analysis.
Auto-calculation of elastic support stiffness Mesh & Link at Column Boundary in the dialog box of Column Support Type refers to automatic division of floor plate elements following the column outlines. This is intended to accurately reflect the effect of floor plate restraints by assigning Rigid Link within the cross-sections of the columns in a flat plate/slab system. For shallow foundations, the modulus of subgrade reaction (proposed by Joseph E. Bowles) on the basis of an allowable bearing stress concept is automatically calculated and entered. SDS then proceeds to non-linear boundary element analysis reflecting the compression-only characteristics of soils. For piled foundations, the user specifies the type, size, embedded length and construction method to compute the stiffness of a pile. The piles can be designated to resist compression only.

Meterial & Section Properties

SDS contains a database representing various materials and sections such as ASTM, AISC, DIN, BS, EN, JIS and KS. The user is free to choose any one from the database. Anisotropic elements can be used to analyze a plate by specifying different thickness data, which form the basis of calculating flexural stiffness in each direction and torsional stiffness. An example of application may be a metal deck floor system whose sectional properties are different in each direction. Thickness data entry for anisotropic elements

Load Generation
		SDS adopts the data entry method, Load Type, which simplifies the input process of specifying Line Load and Area Load frequently encountered in floor plate analyses. Load Type can define typical superimposed dead loads such as non-structural masonry or partition loads and finish loads. You may construct a database to apply to other analysis models via the Import function of the program.
	Construction of DB for dead & live loads SDS, being a design tool for slabs, is empowered by serviceability checking capability. Often, serviceability criteria are defined in terms of forcing functions. SDS is capable of performing eigenvalue and time history analyses using the floor plates modeled for strength design. Application of a time history analysis becomes a simple matter as the walking loads (Baumann, JIA, etc) are contained in the database. Walking loads supplied by DB

SDS simplifies the design process of piled mat design, which eliminates the process of trial and error practiced by structural engineers.

Automatic Pile Placing
	The Data Conversion function permits automatic transfer of the reaction data of the overall structure to the SDS model file for calculating the number of piles. The effects of wind and seismic loads are accurately reflected into the reactions. The automatic pile-placing feature considers column and wall layouts and the minimum pile spacing. Automatic Pile Placing
Pile Spacing Checks
	It identifies the piles that do not satisfy the spacing requirement based on the diameter of the piles.
Automatic Foundation Mat Generation/Modification (Assign/Modify Basemat)
	SDS automatically generates a Basemat reflecting the edge distance. Creating strip footings is also a simple task as new grid lines can be easily added and modified. Auto-generation/modification of a basemat

SDS automatically generates finite elements based upon entered Objects and the maximum element size specified by the user. SDS now contains Multi-frontal Solver, which reduces analysis time substantially.

Post-processor

SDS is capable of automatically generating load combinations pursuant to various design standards. In the case of analyzing foundation mats, it generates load combinations of service loads and factored loads in addition to applying Scale-up factors for seismic loads based on a response spectrum analysis. Using the Envelope feature, the maximum reactions and member forces resulting from each load combination can be easily verified.

Displacement Contour of a floor plate

Internal forces of slab elements can be displayed in the form of a contour or text, which are presented by a unit width. The internal forces of specific sections can be examined by applying Cutting Diagram.

Internal Forces of a floor plate (Text Output View)

Floor Plate Force Diagram (Cutting Diagram)

Pile reactions that exceed the allowable capacity can be easily verified by using Display Range Filter. For non-piled conventional foundation mats, the Area Reaction feature displays a contour representing reactions per unit area.

Pile Reaction Diagram

Vibration Mode Shapes of a plate structure can be examined through an animation produced by the program.

The Time History Text function allows the user to examine the locations where the maximum displacement, velocity and acceleration occur as a result of a time history analysis for evaluating serviceability. Time History Graph produces the time history graphs of displacement, velocity and acceleration at a specific node.

The FFT (Fast Fourier Transform) feature analyzes the characteristics of time history frequencies. SDS provides analysis results in graphs that can be compared with the serviceability criteria.

SDS designs reinforcing steel for a given floor plate or foundation mat in accordance with ACI 318-95/99/02 and other design standards. It checks punching shear at the locations of concentrated load points, columns and piles. The maximum shear stress at the failure planes may be examined to reflect the effect of shear transfer component. Rebar Contour supplies the required reinforcing steel in each direction in Slab Design Result.

Punching Check Ratio alerts the user of the locations where high 2-way punching shear stresses are expected.

Structural Calculations