S T R U C T U R A L A N D E A R T H Q U A K E E N G I N E E R I N G S O F T W A R E

INTEGR ATED DESIGN OF

CONCRETE SL ABS AND BA SEMATS

FOR WINDOWS 95® & WINDOWS NT®

ANALYSIS AND DESIGN OF SLAB SYSTEMSUSING THE FINITE ELEMENT METHOD

ANALYSIS AND DESIGN OF SLABS AND BASEMATS

Slab systems are a very special class of structures. They are characterized by their simplicity in geometry and loading. They are typically composed of horizontal plates supported vertically by beams, columns and walls. The loading in general is comprised of vertical point, line and surface loads. Basemats share the same characteristics as those of elevated slabs, with the exception that basemats are supported on soil and loaded by columns and walls. Most commercially available finite element programs can be used to model slabs and basemats. However, such software packages do not recognize the unique characteristics of slab systems, resulting in excessive solution times and significant loss of productivity and man-hours. Also, such packages are difficult to use and are not integrated with slab design algorithms that will produce information directly usable by the structural engineer.

Recognition of this problem, nearly two decades ago, led to the development of the SAFE System based upon the finite element method. SAFE is special purpose software that automates the analysis and design process for the structural engineer, lending greater sophistication to the engineering of slab systems. It is designed to minimize engineering man-hours and processing time associated with the design of concrete slab systems. SAFE is a completely integrated product that operates within the Windows95/NT environment. It features a powerful graphical user interface unmatched in terms of ease-of-use and productivity. Creation and modification of the slab model, execution of the analysis, checking and optimization of the design and production of graphical displays of the results are all controlled through this single interface.

The SAFE program will analyze and design slabs of arbitrary geometry including drop panels, openings, edge beams and embedded beams subjected to vertical point, line or surface loads. Column supports, wall supports, or soil supports for basemats can be modeled. Discontinuities in the slab system, due to slip joints or differences in slab elevations can be included. The slab is modeled with orthotropic plate elements. The beam element allows for bending, torsion, and shear deformations.

the SAFE system

FLAT SLAB

BASE MATS

CRACKED DEFLECTIONS AND PATTERN LOADING

Á New fully integrated graphical user interface within Windows 95/NTÁ Fast object-based model generationÁ CAD-like drawing utilitiesÁ Automated meshingÁ New fast equation solver and element formulationsÁ International Design CodesÁ Evaluation of punching shearÁ Automatic reanalysis for cracked conditionÁ Graphical displays of design resultsÁ Database outputÁ Online help

User Friendly Graphical Interface

MODEL BUILDING• Automated templates for typical slabs and basemats• Powerful new slab model builder with automated mesh generation• Accurate dimensioning with guidelines and snapping• Quick draw options to create elements with single mouse clicks• Easy editing with move, merge, replicate and mirror• Cut, copy and paste options• Powerful grouping and selection options• On screen assignment of properties, loading and supports• Unlimited levels of undo and redo• Multiple views in 3D perspective with zooming and panning• Import and export of .DXF file for model geometry• Right button click for instantaneous current element or joint information• English, MKS and SI units

INPUT/OUTPUT GRAPHICAL DISPLAYS• Undeformed structural geometry• Loading diagrams• Deformed shapes with animation• Slab displacement, moment, shear and bearing pressure contours • User controlled stress averaging for contours• Beam moment and shear diagrams• Reaction force diagrams• Integrated strip moment and shear diagrams• Numerical values of results shown as pointer moves over display

WHAT'SNEW

Analysis Options• Arbitrary geometry of slabs and basemats• Thickness variations, drop panels and openings• Edge beams and other beam support conditions• Slab shear and moment discontinuities due to slip joints or slab elevations• Column, wall or soil supports• Point loads, line loads, surface loads, self-weight• Orthotropic bending with thick and thin plate options• Beam element with flexural, shear and torsional deformations• Variations in soil modulus of subgrade reaction• Stiffness effect of walls• Automated cracked property calculations• Nonlinear no-tension soil model• Multiple load cases

TEMPLATES FOR FAST MODEL GENERATION

The design options of SAFE allow for the flexural design of reinforced concrete slabs and basemats and the flexural and shear design of beams according to the specifications of a variety of International Concrete Design Codes. American, British, Canadian, New Zealand, Indian and Eurocode Code options are currently available. The slab design is built around a set of design strips, which gives the user control over the slab reinforcement location and layout. This flexibility is not compromised by variations in slab geometry such as skewed configurations, drop panels, openings and irregular support conditions. The design strip moments are obtained by integrating the finite element stresses using an algorithm that always satisfies equilibrium and accounts for the effects of twisting moments. Reinforcing is based upon controlling design-loading combination.Beam design may include T-beam effects. Code based punching shear checks are made around column supports and point loads. Deflection calculations are based on cracked sections using current reinforcement design and service load moments.

the SAFE slab design options

Á Graphical display of required reinforcing with bar sizesÁ Graphical display of integrated strip design momentsÁ Graphical display of punching shear stress ratiosÁ Tables of flexural reinforcing for slabs�Á Tables of flexural and shear reinforcing for beamsÁ Tables of details of punching shear checksÁ Design information in database format

the SAFE slab design output

SAFE CONCRETE DESIGN

SLAB REINFORCINGPUNCHING SHEARCRACKING

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SLAB MOMENT DIAGRAMS & DEFORMED SHAPE

SLAB PUNCHING SHEAR & REBAR LAYOUT

DESIGN TABLES

The CSI logo is a registered trademark and SAFE is a trademark of CSI. Windows 95 and Windows NT are trademarks of Microsoft Corporation.© 1998 Computers & Structures, Inc.