# Finite elements

The structural frame
The construction
The reinforcement I
The reinforcement II
Quantity/Cost estimation
Detailing drawings
Introduction >

Wind and Seismic Forces >
Structural model and Analysis
Slabs
Seismic behavour of frames
Appendix A
Appendix B
Appendix C
Appendix D
Introduction >
Modelling slabs

Materials
To be continued >
Introduction

## General

 (1) two-way,  (2) one-way,  (3) two-way three-edge-supported,  (4) two-way two-edge-supported,  (5) cantilever

Slabs are two dimensional structural elements bearing loads transverse to their plane.

## Structure with various types of slabs

Slabs are either isostatic (e.g. one-way, cantilever) or hyperstatic (e.g. two-way) structures. Hy-perstatic structures redistribute stresses and provide high safety both under bending and shear-ing.

## Assumptions for modelling slabs

In this chapter, two basic assumptions are adopted for modelling slabs allowing their analysis separately from the rest of the structure. Specifically,

1)    The slab supports on beams and columns provide vertical restraint.

2)    The slab supports on beams and columns provide no rotational restraint.

Practical calculation of rectangular slabs is performed with the computational methods proposed by two great engineers, Marcus and Czerny.

The two-dimensional finite element method is not applicable without the use of software. The reader of this book could use the related software or other similar software, in order to re-run all the examples in the book and especially to create different variations, so as to comprehend the behaviour of slabs and become familiar with the order of magnitude of stress resultants.

The pi-FES module, called SLABS, for modelling and analysing isolated as well as continuous slabs using two-dimensional finite elements, yields results similar to those of the theory of elasticity as developed and tabulated by Czerny. pi-FES generates automatically both independent and adverse loadings, therefore only the results are requested from interface.

In order to understand the method, three examples are presented using the related software.