1. Staff Deve
elopmen Progra
nt amme (S
SDP) on
RECE
ENT AD
DVANCE IN F
ES FINITE E
ELEME
ENT
MOD
DELLIN
NG
19-30 January, 2009
Sponsored b
by
All In
ndia Co
ouncil fo Tech
or hnical E
Educati
ion
(AICTE New D
E), Delhi
Coo
ordinator
JOB THOMA
AS
Div
vision of C Eng
Civil gineering g
School o Engine
S of eering
Coc
chin Univ
versity of Science and Te
f e echnolog
gy
Coochin – 6 022, Kerala
682 ,
http://civ
vil.cusat.
.ac.in
2.
3.
4.
5.
6.
7. Transverse Bending Analysis of Concrete Box-Girder Bridge
Dr. Babu Kurian,
Assistant Professor, Department of Civil Engineering, Mar Athanasius College of
Engineering, Kothamangalam – 686 666.
Box-girder bridges are widely used throughout the world because of their high structu
efficiency as well as better aesthetics compared to open-web type sections. The cro
section of the box-girder may take the form of single-cell, multi-spine or multi-cell. T
single and multi-cell box-girders (made of reinforced or pre-stressed concrete) w
vertical or inclined webs are preferred as economic and aesthetic solutions for ov
crossings, under-crossings, viaducts, etc. The present trend in concrete box-girders is
use thinner webs and flanges in order to reduce self-weight.
The various structural actions involved in box-girders are flexure, shear, torsion, warpi
and distortion, in which the effects of distortion and warping are particularly significa
in thin-walled box-girder bridges. The typical box-girder behaves like a beam, but
longitudinal flexural action is accompanied by transverse bending, and is affected
distortion and warping of the cross-section.
In design practice, the longitudinal action and transverse action are often analyz
separately. The box-girder bridge is modelled as a beam for longitudinal action and a
frame (of unit width) for transverse action. Here, the transverse action induced
vehicular loading is described.
The Beam on Elastic Foundation (BEF) can be used for the transverse bending analy
of single-cell box-girders. However, the BEF methods are not commonly adopted
practice, as they require involved calculations. Three-dimensional finite element analy
(3DFEA) provides an alternative computational method, which addresses both transver
and longitudinal actions integrally.
In design practice, the rigor of BEF and 3DFEA is often avoided, and simple fram
analysis is carried out on a frame of unit width (Fig. 1), to obtain the transverse bendi
moments. Longitudinal bending action is similarly simplified by modeling the bridges
a simple beam spanning between bearing supports. In thin-walled box sections warpi
stresses (in the longitudinal direction of the bridge) are developed due to torsion a
distortion. To account for the error arising out of the neglect of this warping effect, t
results of simplified analysis are sometimes enhanced by some percentage (10 percent
so).
Errors in Simplified Frame Analysis (SFA)
The errors in SFA can be attributed to the following:
(i) Neglect of distortion analysis which can result in serious errors when t
8. FEM MODELLING OF NATURAL GEOTEXTILES
K. S. Beena
Reader, School of Engineering, Cochin University of Science and Technology, Kochi, Kerala – 682 022, INDIA,
Email:beenavg@cusat.ac.in
ABSTRACT – The importance of Natural Geotextiles in Civil Engineering cannot be over emphasized, the major
application area being soil stabilization, erosion control and drainage. With the better understanding of the properties
and functions of these materials, they can be utilized in a better way and this is possible by way of numerical modeling.
In this paper using a three dimensional nonlinear finite element analysis, the versatility of the discrete analysis and the
need to represent the frictional properties of the natural geotextiles, while modeling, are emphasized. A model
foundation using coir and bamboo as natural geotextiles is taken for the study and the results are compared with
laboratory models.
1 INTRODUCTION
The construction material Geotextile introduced new techniques, design and construction methods in Civil Engineering.
These are made of long, flexible and thin fibrous material with high tensile strength. These characteristics are essential
for good contact with soil particles and there by ensuring stress transfer by friction. The natural geotextiles like jute, coir
and bamboo are having these characteristics and can be looked upon as an alternative for synthetic materials, especially
in developing countries like India.
One of the areas where these natural materials can be effectively used is in unpaved roads. Laid over subgrade
before placing the sub-base it act as a separating media which prevents the inter mixing of the material, it assist in
drainage by removing excess water and provide improvement in bearing capacity by virtue of their reinforcement value.
In the present study, the load deformation characteristic of a reinforced foundation bed is analysed, using coir and
bamboo as reinforcement.
The Finite Element Method has indeed become a highly useful tool for the numerical analysis of problems
involving soil and reinforcement. An early approach to considering reinforced soil has been based on “unit cell”
approach suggested by Romstad et al. (1976), which introduces the effect of reinforcement in the constitutive law of the
soil matrix by homogenization methods. This approach may be appropriate only when there are numerous reinforcing
elements that enable the soil reinforcement matrix to be considered as a homogeneous material. In many cases, the
reinforcement elements and the interface behaviour need explicit modeling to get realistic results. Here a three-
dimensional finite element analysis is resorted giving individual attention to soil, reinforcement and the interface.
2 MECHANISM OF REINFORCEMENT
The mechanism of reinforcement in reducing the settlement can be explained (Beena, 1994) by considering a block of
soil subjected to a compressive load under the effect of which it settles axially and deform laterally as an elastic medium
as shown in Fig.1 (a). The same block with reinforcement, having higher modulus of elasticity, included therein is
subjected to the same load as shown in Fig.1 (b). If such reinforcement can be assumed to be perfectly bonded with the
surrounding soil, it is obvious that soil and the reinforcement must deform laterally by the same amount and this must
necessarily be much smaller than the same in the unreinforced case. This is on account of the fact that the reinforcement
permits the soil to move laterally by the same distance both can move together. This naturally brings down the axial
deformation. It is obvious that under the integral action assumed in the above, the higher the modulus of the
reinforcement lesser the settlement.
This is subjected to a serious limitation when it comes to the soil and its reinforcement in terms of the bond that
can develop between the two, for which one has to depend on frictional bonding due to mechanical friction
9. STRUCTURAL DAMAGE IDENTIFICATION IN LAYERED
COMPOSITES USING FREQUENCY RESPONSE METHOD.
Saraswathy B. 1, Asha V. 2, Lalu Mangal 3, Rahul Leslie4, Ramesh Kumar R. 5
1 Selection Grade Lecturer in Civil Engineering, T.K.M.College of Engg; Kollam,
2 Postgraduate student, T.K.M.College of Engg; Kollam,
3 Asst.Professor in Civil Engineering, T.K.M.College of Engg; Kollam,
4 Asst. Engineer, Design Wing, Kerala P.W.D, Trivandrum,
5 Structural Design and Engineering Group, VSSC, Trivandrum
Abstract
This work aims to establish a vibration-based damage identification method
for laminated composites. This new on-line technique uses the changes in
Frequency Response Functions (FRFs) of a sound structure and that of a
damaged structure for structural damage identification. There are strong
needs and requirements for on-line damage (delamination) detection and
health-monitoring techniques of composite structures. Since damage alters the
dynamic characteristics of a structure, several techniques based on
experimental modal analysis have been developed in recent years. Vibration
signature, e.g.: modal properties or frequency response function data is a
sensitive indicator of structural physical integrity and thus can be used to
detect damage. Most of the reported works are based on changes in modal
parameters. A new damage detection and assessment method is proposed
using the FRF data.This newly developed technique covers the major steps of
damage detection-existence, localization and extent, using the Frequency
Response Function Curvature method.
1. Introduction
As structures degrade or experience damage from natural disasters, they will
no longer behave as they were originally designed to, which could pose safety
and reliability hazards. Since damage will alter the stiffness, or energy
dissipation capabilities of a system, the measured dynamic response of the
system will also change. Much like a human’s routine checkup at the doctor’s
office, structural health monitoring consists of observing a system’s response
periodically and implementing damage diagnosis strategies. This helps
engineers to ensure that the structure is in good health, and if necessary, to
employ prompt measures to rectify any damage.
10. Finite Element Solution of
Reynolds Equation using
Matlab
Dr. Jayadas N. H
Reader
Division of Mechanical Engineering
School of Engineering, CUSAT
11.
12. DYNAMIC BEHAVIOUR OF PILE IN A LAYERED SOIL MEDIUM
Jaya K P
Assistant Professor
Structural Engineering Division
Anna University, Chennai - 600 025
jayakp@annauniv.edu
INTRODUCTION
Considering the frequent occurrence of earthquakes all over the world, studies on the behaviour of
structures under dynamic excitations are of great importance. There are many parameters affecting the
dynamic response of structures, such as: the type of structure, type of foundation, soil characteristics
etc. The observations from the earthquake damaged sites show that, the local soil properties,
underground and surface topography of soil medium and the foundation geometry have an important
effect on the dynamic behaviour of structures. The local soil conditions and the interaction between
soil and foundation will affect the dynamic behaviour of a structure in three different ways.
i. The characteristics and frequency content of the motions that occur at the free surface of a soil
deposit resting on a base rock, will differ from that of the motions generated at the top of base
rock. The motions at the free surface of the soil layer are functions of soil properties as well
as the type and frequency contents of the waves. In general, the motion is amplified. This is
known as soil amplification effect.
ii. The characteristics of the seismic motions will be modified by the presence of a rigid or stiff
foundation, particularly for embedded foundations. The modification is due to the reflection
of waves at the rigid face of the foundation. This phenomenon is referred to as the wave
scattering or kinematic interaction effect. The base will experience some horizontal and
rocking displacement.
iii. The inertia forces in the structure during its vibration result in a base shear and an overturning
moment, which will give rise to additional deformations and displacements. These will cause
deformations in the surrounding soil and thus modify the motions at the base. This
phenomena is known as inertial interaction effect.
The total interaction effects between the unbounded soil media and the structure, resting on or
embedded in the soil, can be referred to as Soil-Structure-Interaction (SSI) effects. It is possible to
characterise SSI analysis methods in a number of ways: linear versus nonlinear cases, continuum
versus discrete formulations, frequency-domain versus time-domain solutions, etc., For the present
discussion, two broad categories of solution techniques are distinguished, such as: the direct approach
and the substructure approach.
13. STADD Lab
EXERCISE 2
SPACE FRAME WITH STEEL DESIGN.
A steel frame with truss members are analysed. After one analysis, member selection
requested. Since member sizes change during the member selection, another analysis
done followed by final code checking to verify that the final sizes meet the requiremen
of the code based on the latest analysis results.
5
8
3
15
7 10
18
6
13
9 25
17 20
2 28
16
23
19 35
27 30
12 38
26
33
29
37 4 40
22
36
39
14
32
1
24
11
34
Load 1
Y 21
X
Z
31
STAAD SPACE
START JOB INFORMATION
ENGINEER DATE 13-Dec-08
END JOB INFORMATION
INPUT WIDTH 79
UNIT METER KN
JOINT COORDINATES
1 0 0 0; 2 0 6 0; 3 10 6 0; 4 10 0 0; 5 5 8.8 0; 6 5 6 0; 7 2.5 7.4 0;
8 7.5 7.4 0; 9 2.5 6 0; 10 7.5 6 0; 11 0 0 3.5; 12 0 6 3.5; 13 10 6 3.5;
14 10 0 3.5; 15 5 8.8 3.5; 16 5 6 3.5; 17 2.5 7.4 3.5; 18 7.5 7.4 3.5;
19 2.5 6 3.5; 20 7.5 6 3.5; 21 0 0 7; 22 0 6 7; 23 10 6 7; 24 10 0 7;
25 5 8.8 7; 26 5 6 7; 27 2.5 7.4 7; 28 7.5 7.4 7; 29 2.5 6 7; 30 7.5 6 7;
31 0 0 10 5; 32 0 6 10 5; 33 10 6 10 5; 34 10 0 10 5; 35 5 8 8 10 5;
14. EXERCISE 1
STAAD SPACE FRAME WITH CONCRETE DESIGN
4m
5m
6m
5m 5m
4m
5m
5m
6m
5m
6m 5m 4m
5m 5m
3.2 m 5m
3.2 m
6m
5m
5m 5m 3.2 m
3.2 m 6m 4m
6m 3.2 m
5m 3.2
3.2 m 6m
3.2 m
3.2 m
5m
3.2 m 6m
3.2 m
Y
X
3.2 m
Z
The above example represents a space frame, and the members are made of
concrete.
Actual input is shown in bold lettering followed by explanation
STAAD SPACE
START JOB INFORMATION
ENGINEER DATE 20-Nov-08
END JOB INFORMATION
INPUT WIDTH 79
UNIT METER KN
Joint number followed by X, Y and Z coordinates are provided below
JOINT COORDINATES
1 0 0 0; 2 16 0 0; 3 16 0 5; 4 0 0 5; 5 6 0 0; 6 12 0 0; 7 6 0 5; 8 12 0 5;
15. STAAD Pro
Introduction
STAAD.Pro is a general purpose program for performing the analysis and desi
of a wide variety of types of structures. The basic three activities which are to be carri
out to achieve that goal - a) model generation b) the calculations to obtain the analytic
results c) result verification - are all facilitated by tools contained in the program
graphical environment
Types of Structures
A STRUCTURE can be defined as an assemblage of elements. STAAD is capable
analyzing and designing structures consisting of both frame, plate/shell and so
elements. Almost any type of structure can be analyzed by STAAD.
A SPACE structure, which is a three dimensional framed structure with loads applied
any plane, is the most general.
A PLANE structure is bound by a global X-Y coordinate system with loads in the sam
plane.
A TRUSS structure consists of truss members which can have only axial member forc
and no bending in the members.
Analysis Facilities
The following PERFORM ANALYSIS facilities are available in STAAD.
1) Stiffness Analysis / Linear Static Analysis
2) Second Order Static Analysis
P-Delta Analysis
Non-Linear Analysis
Multi Linear Spring Support
Member/Spring Tension/Compression only
3) Dynamic Analysis
16. APPLICATION OF FINITE ELEMENT TECHNIQUE IN
FREQUENCY ANALYSIS OF LOW-RISE MASONRY BUILDINGS
S Raghunath
Professor, Department of Civil Engineering
BMS College of Engineering
Bangalore 560019
e-mail: sraghunath_bms@yahoo.co.in
Masonry
Masonry is an assemblage of units (such as bricks, blocks, stones etc) bound togethe
with the help of a binding material that is commonly known as mortar (cement, lime
mud mortar etc). It is therefore obvious that the structural (and architectural) properties o
masonry is mainly governed by the strength, elastic and geometric properties of th
masonry units and the mortar. There are other factors which also influence the behaviou
of masonry, such as;
• Bond strength (between unit and mortar)
• Slenderness ratio of masonry
• Workmanship
• Nature of loading and boundary conditions
• Geometry of openings
• Moisture transport between mortar and unit
• Effects from weathering such as wetting/drying and creep
It may interesting to note that masonry components/buildings are essentially continuum
structures with strength and elastic property distributed all over the structure, henc
conventional structural analysis may not reveal the true structural behaviour of masonry
This obviates the need to apply Finite Element Analysis (FEA) to study the nature o
stresses developed in masonry. It is quite well known that FEA is a very powerful tool fo
analysis of such continuum structure. The power and storage capacities of the moder
day computers have given the researchers and designers a choice of wide variety of user
friendly commercial FE packages. These packages are often loaded with many module
that are capable of handling different types of analysis such as linear and non-linea
analysis, static and dynamic analysis, optimization, thermal analysis etc. They are als
complemented with a wide variety of choice of ‘elements’. Almost all the packages ar
usually supplied with user-friendly pre-processor and post-processor. Indeed, nowaday
the use of such ubiquitous packages is quite common. However it is important to realiz
that a prior understanding of structural masonry is very much essential before on
analyses the mathematical model.
In this lecture notes the usefulness of adopting FEM technique in obtaining the natura
frequencies and mode shapes of box-type masonry buildings is highlighted
17. CONCEPTS OF FINITE ELEMENT ANALYSIS:
1D & 2D BOUNDARY VALUE PROBLEMS
Dr. Palivela Subba Rao, JNTU College of Engineering, Kakinada, (AP).
1.0 INTRODUCTION
The nature is full of varieties of phenomena, viz., biological, chemical, geologi
physical etc. A phenomenon is defined as an interaction of various parameters involved
the phenomenon influencing the phenomenon. All the phenomena in the in nature can
expressed either in terms of differential equations or in terms of integral equations
algebraic equations mathematically called as mathematical models. These models help t
scientists and engineers to predict and forecast quantities of their interest. Mathemati
models in terms of differential equations of the all phenomena in the nature are classified
to three, viz., Boundary Value Problem (BVP), Initial Value Problem (IVP) and Eigen Val
Problem (EVP). Specified boundary conditions decide the physical problem to be categoriz
as BVP or IVP or EVP. Problem is said to be BVP, if all the required boundary conditio
are specified at different locations on the boundary of domain. Otherwise, it is said to be IV
if the boundary conditions are specified at one point on the domain. Mathematical mode
which has multiple solutions, as in case of buckling problems, free vibration problem
(different modes) are called as EVP. Here a few examples on Boundary value problems fro
engineering applications are discussed for understanding the concepts of Finite Eleme
Method.
1.1 MATHEMATICAL MODELING OF A BAR PROBLEM: (Differential Equation
The bar structure is a 1Dimensional member subjected to axial force as shown
Fig.1. In general, axial force on the bar structure may be either body force g ( x) / unit vol ,
traction t ( x) / unit length or concentrated load, P or their combination. As the bar structure
under the action of loads, the each and every point of the bar will be displaced to n
position. The function (equation) indicating displacement at any point in the bar structure
called as displacement function/ displacement field.
18. BEHAVIOUR OF A MULTIYSTOREY RC FRAME
WITH OPEN STOREY AT MULTIPLE FLOORS
Thomaskutty Jose 1 and Job Thomas 2
ABSTRACT: Reinforced concrete (RC) framed building having open storey at ground floor
to provide parking facility and also having open storey at upper storey to provide recreational
halls is vulnerable to the lateral deformation when subjected to earthquake loads. This paper
presents the analytical results of a RC frame having soft stories (open halls) at multiple floors.
An eight storey RC frame with a lecture hall (7m) and a verandah (2m) has been analyzed
using STAAD package to study the effect of open halls at multiple floors. The brick infill
walls have been modeled using plate/shell elements having no rotational stiffness. The
columns and beams have been modeled using the 3D beam elements. The analytical results
such as storey drift, bending moment and shear force in beams and columns have been
compared. The analytical results indicate that the presence of open halls at multiple floors
increases the maximum storey drift (of soft storey) significantly. Open storey at multiple floor
in RC frames induces higher moment and shear force in columns This paper presents the
details of design forces of structural elements of a RC frame with and without open stories at
multiple levels.
the soft ground storey of the RC building was found
INTRODUCTION to be significant when compared to the storey drift in
the upper storeys having infill wall panels (Murthy et
In multi-storey reinforced concrete (RC) al., 2003). However, the details of the results of RC
buildings meant for offices and hotels, many storey frame having soft or weak stories at multiple floors
will be intentionally left open without masonry walls were not found in the literature (Dasgupta and
for the conveniently utilizing the space in the future. Murthy 2003, Mahashabde et al. 2003).
Often, structural engineers conveniently neglect the
effect of masonry walls in RC building. Analytical RESEARCH SIGNIFICANCE
studies by Murthy et al. (2003), Goel et al. (2002)
Mahashbode et al. (2003) and Dasgupta et al. (2003) This paper presents the details of FE analysis of a
indicated that infilled frame offers increased RC frame considering the stiffness contribution of
resistance against lateral loads. The difficulties to infill masonry wall panels. The conventional shell
model the structural behavior of the infilled masonry element has been modified by releasing the rotational
panels in the RC frames have been indicated in these stiffness and utilized for modeling the infilled
literatures (Dasgupta and Murthy 2003, Mahashabde masonry panels in RC frames. The analytical results
et al. 2003). This paper presents details of modeling of a RC frame with and without infill masonry panels
of masonry panels in FE analysis. at multiple floors have been discussed in this paper.
The analytical results of the RC frames with weak
storey having no infill masonry walls in the ground DETAILS OF RC FRAME
floor, to be used as car parking area, have been
discussed in the literature (Dasgupta and Murthy An eight storey RC frame building with five
2003, Mahashabde et al. 2003).The presence of infill rooms of size 7mx7m and having 2m wide verandha
masonry or reinforced concrete walls in upper storey has been analysed using STAAD package. The size
makes them much stiffer than the open ground storey. of beams at foundation level and beam supporting 2.0
Thus, the upper storeys, which are not soft, move span has been taken as 300mmx 300mm. The size of
almost together as a single block when subjected to beam supporting 7m span has been taken as
lateral loads (Murthy et al., 2003). The storey drift in 300mmx600mm. The size of column is taken as
500mmx 500mm. The RC frame having no masonry
1
Lecturer in Civil Engineering, Carmel Polytechnic wall at ground floor, at two floors at the bottom, at
College, Allapuzha, kerala three floors at bottom and at four floors at bottom
2 have been considered in this study. The details are
Lecturer, School of Engineering, Cochin
given in Fig 1. The frame has been designated to
University, Kerala; Corresponding author, Email:
indicate the storey at which the masonry wall is not
job_thomas@cusat.ac.in
available. Thus, F1/2/3 is the designation of the