nirman book

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ILL [EAGLE]

NIRMAAN...of a more beautiful world

sIs ueIIanu y2008J ar

A Civil Engineering Society, IIT Delhi Publication


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Before you start.Training & Placements continues to be mostimportant thing for every student right from thetime of his entry into IIT. And when theplacements are as good as this years, how couldwe have lagged behind in providing you the dataregarding the same. We hope that you would likeour exclusive report on Placements this year so

far including other interesting data that providesan overall picture of the performance of thestudents of the department. Among otherarticles, we have been very peculiar about thevariety - Btech, Mtech, PhD, Alumni, GuestColumns by Professors from Universities fromUS/UK, Newspaper clippings regarding thedepartment, TnP statistics, Student performancedata and experience based article by HighlyExperienced Engineers gives this magazine aunique status in the campus and an edge to theCES over all other departmental societies. Iwould like to thank them all for their support and

contribution.First issue of Nirmaan was an achievement forthe Society. It was liked by all those who cared toread it. There had been requests for bringing outthis magazine atleast twice a year. But it is ourlimitation of time and resources that we areunable to bring this magazine frequently. We dokeep in mind the quality you expect from themagazine that involves your money and hence,once in a year seems to be a better idea as fornow. I hope that this second edition will be muchmore useful to you than our first edition.Please note that this magazine has nocommercial interest and there is a spacelimitation too. Hence, the References of many ofthe research based articles have been removed.We are sorry for this deletion. The references, ifrequired, can be provided on request.It was good to see the involvement of some newfaces in the Magazine team this year which is agood sign to all the contributors and readers ofthis magazine that this will continue to come outin the future.Before leaving CES, I would like to thank all thosewho helped in bringing out this magazine since

its very first issue. A major credit of this goes toBoard for Student Publications, IIT Delhi, and its2004-05 team, for it helped me in learning the ar tof bringing out a magazine. Secondly, I thankNishit Garg, ex-General Secretary, CivilEngineering Society, on whose proposal westarted the work of the first issue. I would alsothank all the students who paid their CES fee ontime that took care of the finance part, and theCES students team, especially AbhinavBhardwaj, Jyoti Shankar Pandey and PrshantBatra for their contributions in collecting theimportant data.

So, enjoy reading..

Saurabh Jain,Ex-General Secretary.

From Editors Desk...Nirmaan.... of a more beautiful world!!! The Journey of 'Nirmaan' hadbegun in September 2006 with its Inaugral Issue. Civil EngineeringSociety (CES) brought a revolutionary idea of departmentalmagazine whose fruit is this issue which you are holding in your hand.This 52 pages magazine is a combined effort of CES team,professors, alumni, and UG & PG students of Civil Engineering.

Nirmaan contains a wide variety of Technical articles which are notonly submitted by students and faculty of IIT Delhi but alumni & foreignProfessors too. Sincere efforts have been made by providing a newinsight to readers regarding the Departmental facts and activities.Special attention is paid towards informative and research basedarticles over literary articles while making the selection from thecollection of submitted articles. The contribution in terms of articlesubmission & suggestion by all the concerned people played a veryeffective role and should be appreciated.

During the last year, CES have organized a lot of academic & non-academic activities like Dimensions, Departmental Cricket Matches,and Seminars & Workshops by eminent persons. This issue highlights

all these activities not only in written but also in pictorial terms. TheCentral 4 pages of magazine contain pictures of different seminars,academic and non-academic activities of Civil Engineering Students.Department plays a crucial role in the development of IIT Delhi, It hasshown its power to the outside world with its innovative ideas. TheNews Column of Nirmaan tries to cover all such news whichenlightens the glory of Department.

We are bringing an online issue of Nirmaan due to world wide highdemand of magazine. Explore the online Issue on official website ofCES i.e. web.iitd.ac.in/~ces/. Students can easily access its onlineissue from the link www.civilmag.ne1.net.

At last, I want to thank all the contributors of the magazine for devotingtheir time for the welfare of magazine specially Dr. Suresh Bhalla,Saurabh Jain, Prashant Batra, Jyoti Shankar. I hope that you willappreciate this coloured issue of magazine and contribute to us withyour innovative ideas.

Regards,

Abhinav BhardwajChief Editor

Special Thanks to all the contributors of magazinespecially:

Civil Engineering DepartmentUndergraduate StudentsPost graduate StudentsFaculty

AlumniForeign ContributorsDr. Suresh BhallaShravan - General Secretary

For Online Issue of NIRMAAN. Visit the following link:http://web.iitd.ac.in/~ces


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INDEXNDEXINDEX

1. Message From President 2Prof. A. K. Nagpal

2. Disinguished Alumni Service Awards - 2006 3

3. Modelling Cities 4Prof. Rex Britter

4. Efficiency and Versatility of Post Tensioning in Building Constructions 6

5. Unrevealed Facts of 2007 10

6. Liquefaction Hazards in Delhi 13

7. Structural Engineer 18

8. CES Album 23

9. Connecting Civil Engineers 27

10. Assessment of Risk 29

11. Slip Form 34

12. Tensegrity Structure and their analysis using Neural Networks 36

13. Particulate Matter 38

14. International Lecture Series 43

15. Build-Operate-Transfer Model For Infrastructure Developments in Asia 44

16. IIT in NEWS 49

CES Team

Pawan R. Gupta

CES Team

Hanumantharao. Ch.

Ajit Kumar Bhattacharyya

Civil Engineering Department

Gita Balakrishnan

Manaswini Behera & Subrata Bhattacharjee

V. Naga Veera Bhadra Rao

Dr. Suresh Bhalla & Prashant Batra

Prashant Kumar & Rex britter

a new Seminar by CES

R. S. Sravan Kumar

INDEXNDEXINDEX


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MESSAGE FROM PRESIDENTdirectly from heart...

Date: 9th December, 2007

The second issue of NIRMAAN is in your hands after a period of one

year. I congratulate the editorial team of Abhinav Bhardwaj and

Saurabh Jain working under the guidance of Dr. Suresh Bhalla for

bringing out this issue.

The issue gives a glimpse of what Civil Engineer is about aprofession which is now exhibiting its grandeur within the country. This

issue also gives interesting statistics on the profile of Civil Engineering

students on batch strength, salary & placements in the industry for last

few years.

It is hoped that NIRMAAN would continue to grow and become

increasingly more encompassing in width and depth.

(Prof. A. K. Nagpal)

Head of Department

Prof. A. K. NagpalHead of DepartmentCivil Engineering, IIT Delhi


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Modelling CitiesGuest Column...

Professor Rex BritterProfessor of Environmental Fluid Dynamics,Department of Engineering, University of Cambridge

Professor Rex Britter Professor of Environmental Fluid Dynamics, Department of Engineering.Research interests include fundamental studies into turbulent fluid dynamics, particularly thoseinvolving buoyancy. This is paralleled with operational interests in the flow and dispersion of hazardousmaterials, conventional pollutant dispersion problems in complex geometries such as cities,formalised model evaluation procedures, urban air quality and sustainable energy use in cities, urbanclimatology and security. Worked extensively with the UK, EU and US Government Agencies andindustry. Recently been on the Steering Committee or a participant in the EuropeanEnergy/Environment projects COST 615, TRAPOS, SATURN, ATREUS and Vice-Chairman of COST732. Led the Cambridge group in the EPSRC funded DAPPLE project on urban air quality in Londonand in the NERC funded UWERN programme on weather research.

Increasing urbanisation and concern about sustainability and quality of life issues have producedconsiderable interest in flow and dispersion in urban areas. My research is mainly within the generaldisciplines of fluid dynamics and thermodynamics. Though slightly obscure in the main, these subjectsare surprisingly pervasive, being central to most Engineering areas, including the major areas ofAerodynamical, Mechanical, Civil, Chemical and Manufacturing Engineering. Within the Universitystrong groups working in these areas are also to be found in Applied Mathematics and Theoretical

Physics, Architecture, Astronomy, Chemistry, Geography, Geophysics, Materials Science, Medicine,Meteorology and Oceanography, Physics, Life Sciences and many more. This pervasiveness and verylong history (Da Vinci made very significant observations and contributions ) is undoubtedly due tomankind living within a fluid environment and due to the strong non-linearity (read VERY difficult), ofthe fundamental Navier-Stokes equation; an equation that reflects in part the work of G.G. Stokes, pastMaster of Pembroke College, Cambridge.Being somewhat of an opportunist this seemed a good area to work in; very pervasive, generally usefuland with little chance of running out of interesting problems to address. A further attraction to mepersonally, but this is definitely just a matter of taste, is that problems of great difficulty, for whichanswers are required soon and with resource constraints are the bread and butter of engineering andthe training of engineers whether at the research or professional level. It is always important to

remember that the essence of Engineering can be summarised with the four attributes ofCompetence, Confidence, Creativity and Judgement; the last being, arguably, the most important.

Some of our recent work has looked at the fluid dynamics and thermodynamics of cities throughseveral distinct though connected themes including air quality in cities, various aspects of securitywithin cities and urban climatology.

The air quality in cities is largely determined by the pollutant emissions, the urban meteorology and theurban topography. The prediction of the concentrations in the atmosphere is essential for thedevelopment of cost-effective mitigation strategies. Mathematical modelling is the technique used forprediction purposes and the development and quality evaluation of mathematical models is importantas too optimistic or too conservative predictions both have major economic and safety downsides.Formal evaluation of the predictive ability of the models ensures an acceptable quality (fitness-for-purpose) of model. This is a surprisingly underdeveloped activity, particularly given the generalconcern with the formal standards and standards of practice that are central to the profession ofengineering. A recently completed multi-million pound project on urban air quality was based aroundthe Marylebone Rd/ Gloucester Rd area in London. Traffic number and behaviour, emissions modelling,urban meteorology, pollutant dispersion and the exposure of pedestrians, cyclists, drivers and bus andtaxi users were all studied. A principal goal of the project was to undertake some large scale releasesof tracer materials within a city and to track them over a range up to around 1 km; the neighbourhoodscale. The multi-disciplinary nature of this project proved to be a source of its success with creativeinputs and collaborations that reduced the limiting isolation often experienced with research work thatis too strongly focussed. Mr Prashant Kumar from IIT Delhi is currently working with me on themeasurement and prediction of the formation and dispersion of nanoparticulate matter within urbanareas; a problem widely perceived to be of increasing importance for health effects in cities.


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Predictions are also required for assessing the consequences of the release of hazardous materials inurban areas. Models are required by emergency responders (e.g. police, ambulance and the firebrigade) that provide realistic predictions in real time and this need drives an interest in simple models

and their quality. Much of this work transfers directly across to aspects of security concerns in cities.

Air quality was the UK governments main concern in a recent white paper on Aviation. Somewhatsurprisingly it is often regulations that push forward engineering. Developers have to convince thegovernment that they can meet the air quality targets with any new buildings or with any expansion ofairports such as Heathrow or Stansted. Our research formed part of a project on the sustainabledevelopment of Heathrow recently tabled in Parliament. The interdisciplinarity of this subject has led tothe setting up of The Institute of Aviation and the Environment at the University of Cambridge, whichbrings together engineers, chemists, applied mathematicians, economists, architects and geographersfrom across the University. It has amazed me how effective and stimulating research can be thatinvolves collaboration across disciplines provided the participants engage fully with their colleagues.

The climatology within cities is the result of the influence of the city on the environment and theenvironment on the city. The city acts as a resistance to the wind, provides an anthropogenic heat andmoisture source, and has a complex surface that is likely to be very effective at absorbing and re-emitting radiation and not absorbing moisture. The urban climatologist wants to understand andquantify these effects; the engineer has similar goals but also wants to apply the understanding in thebroad areas of the design of the built environment (materials selection, spatial design, human comfortetc.), energy use, land use, transport, public health, security and particularly the sustainability of theurban environment. The engineering topic of materials selection (and development) has a stronginteraction with urban climatology in determining the scale and strength of urban heat islands and thepossibility of their mitigation. Urban heat islands and spatial design impact upon thermal comfort

(indoor and outdoor). This produces consequential changes in energy requirements and the impact ofthe release of that energy (through heat) to the urban canopy. There is a strong interconnectednessamong the various engineering disciplines, urban climatology, behavioural sciences and otherdisciplines that will determine the sustainability of our cities.

Our work focuses on the use of statistical descriptions of the geometry, flow and transport processesfor mass, momentum and energy within and above the urban canopy to determine the wind, thermaland moisture environments in a city. The influence of the urban geometry and the heat and moisturetransfer processes on the temperature and moisture fields within the city can be used be investigatethe energy requirements for heating and cooling of buildings that are subject to the heat islandphenomenon.

Most of the research requires an interdisciplinary approach and it is exciting to be doing work like thiswhere you have excellent engineers working alongside leading scientists, and then you can throw theissues open to international experts in geography, economics, law and many other disciplines. A recentvisit from the Prime Ministers Office was impressed to have such a strong team in the one room andwho knew each other well. Top-ranked Universities like Cambridge and the IITs are in the strongestposition to put teams like this together.

Further Reading: Britter, R.E. and Hanna, S.R. (2003) Flow and dispersion in urban areas. AnnualReview of Fluid Mechanics, 35, 469-496

Modelling CitiesGuest Column...

Professor Rex BritterProfessor of Environmental Fluid Dynamics,Department of Engineering, University of Cambridge

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Efficiency and Versatili ty of Post-Tensioning in Building Construction

Pawan R. Gupta, Ph.D., P.E., P.Eng.Technical Director, Post-Tensioning InstitutePhoenix, AZ

IntroductionPost-tensioning (PT) is an efficient structural system that offers many benefits in a wide rangeof construction, repair, and rehabilitation applications. The efficiency and economy of post-tensioning system stems from its efficient use of high strength materials. Post-tensioning hasbeen successfully used throughout the world for small as well as large projects for over 40

years.

Use of High Strength MaterialsPost-tensioned concrete is a perfect balance of two materials which complement each other.Concrete is strong in compression but relatively weak in tension, Fig. 1. The tensile strength ofconcrete is about 10% of its compressive strength. Prestressing steel, on the other hand, has avery high tensile strength (270 ksi (1862 MPa)) which is about four times that of commonreinforcing bars. By combining the strength of the two components a post-tensioned membercan resist both compressive and tensile stresses caused by the applied loads throughout theservice life of the structure.

In the flexural design of non-prestressedconcrete members, the tensile strength ofconcrete is typically neglected; it isassumed that the concrete is cracked andall tensile stresses are resisted byreinforcing steel. Typically less than half ofthe concrete cross-section of a non-prestressed concrete member is actuallyused to resist flexural compressivestresses. Resisting flexural loads with non-

prestressed concrete is inherentlyinefficient, since most of the concreteserves to add weight and separate the

reinforcing bars that are in tension from the small portion of the concrete section that is incompression and participates in carrying the load.

In a post-tensioned concrete member the steel is put into tension shortly after the concrete isplaced, by elongating it with hydraulic jacks and anchoring against the concrete throughspecially designed anchoring devices, Fig. 2 shows the components and constructionsequence for an unbonded post-tensioned slab.This pre-compresses the concrete. Since concrete is relatively strong in compression these

forces are easily resisted by the concrete and help in compensating for the tensile stressesthat would be generated when the member is subjected to loads. This significantly increasesthe load necessary to cause cracking in concrete. Post-Tensioned concrete members can bedesigned to have minimal amount of cracking during normal usage. Since all of the concretesection is participating in post-tensioned members, it is inherently more efficient and able touse the high strength materials effectively.

Flexibili ty in DesignThe designer of a post-tensioned structure has a tremendous amount of flexibility inchoosing the amount and location of the prestressing steel to best resist the anticipated

loads and deflection. The depth within a structural member can be varied to providecompression where needed. Post-tensioning also allow the architects and designersflexibility in placement of columns. The horizontal alignment of tendons can also be easilyadjusted to follow the load path easily, see Fig. 3. The ability of the prestressing steel to

Figure 1: Concrete Member Subjected to Loads


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Efficiency and Versatili ty of Post-Tensioning in Build ing Construction


change horizontal alignment also helps in providing enormous flexibility in the locations ofopenings and obstructions such as plumbing and heating and ventilation ducts, see Fig. 4. Thedesigner can easily vary the amount of force in a particular area by adding tendons to spanlonger distances without columns or carry additional loads. This flexibility gives the designer apowerful tool to meet the needs of even the most complex engineering challenges.

Benefits of Post-TensionedConstructionPost-Tensioning provides someunique benefits and advantagesthat are leading to rapid growth inits use. These benefits include:Higher Structural CapacityLonger spans are possible withsame structural depth for post-

tensioned members. In buildings,this can mean larger column-freespaces and greater flexibility infloor space. Spans up to 40-50 ft(12-15m) are common in standardpost-tensioned floor systems. Inbr idges, par t icu lar ly whencombined with segmental bridgeconstruction techniques, clearspans of several hundred feet are

not unusual

When longer spans are not required, post-tensioned concrete can provide equivalent orsuperior performance as compared to RCC members with significantly less structural depth.In buildings and parking structures, PT structural members are normally about 30% shallowerthan other comparative RCC and structural steel floor systems for the same span. This canreduce building height, and the cost of all related building components, such as plumbing andelectrical systems and curtain walls. In multistory buildings the reduced structural depthpossible with post-tensioned concrete often permits the adding of one or more floors with noincrease in total building height. In the case of underground structures, this can lead to

reduction in the cost of excavation, soil retention systems and dewatering in areas with highwater tables.

7

Figure 3: Flexibili ty in the Layout of Tendonsin a 2-Way Post-Tensioned Slab

Figure 4: Alignment of Post-Tensioning Tendonsaround Openings

Figure 2: Components and Construct ion sequence for anUnbonded Post-Tensioned Slab (adapted from Ref. 2)


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Efficiency and Versatili ty of Post-Tensioning in Building Construction


Material SavingsStructural efficiency of PT can also result in significant savings in steel and concrete. Post-tensioned concrete members generally contain about 30% less concrete as compared toRCC members designed for equivalent load, span and performance. With the rising cost ofsteel and concrete, this can be a major factor in the overall economy of a structure.

Architectural Versatility

PT is used in a wide variety of structures, ranging from every-day applications such as groundsupported slab foundations for residential and light commercial construction to more exoticengineering structures such as long span bridges and multistoried buildings.

Cast-in-place, post-tensioned concrete can be easily adapted to accommodate complexgeometry and other special design challenges necessary to meet the architectural needs of aproject. Curved shapes, non-symmetrical layouts, and unusual design loadings can easily behandled with post-tensioned concrete. Longer slender members with large spaces between

supports are possible with post-tensioning--giving the architect freedom to create structuresthat are both functional and aesthetically pleasing, see Fig. 5.

ServiceabilityPT structures are durable and require little maintenance. The compressive forces that areapplied to a structure during prestressing result in better crack and deflection/vibration control.Monolithic connections between slabs, beams, and columns can eliminate maintenance-intensive joints between elements. PT is often preferred over other types of structures in highlycorrosive environments near the sea coast.

Environmental ImpactSustainable engineering is thecurrent buzzword in structuralengineering and architecture. It isimportant to understand theenvironmental impacts of thematerials and structural systems weuse and to try to minimize thoseimpacts as much as possible toprotect our future resources and

quality of life. The use of post-tensioning can help to lower theenvironmental impact of a concretebuilding. As noted above, thest ruc tu ra l e f f i c iency o f PT

particularly when coupled with high strength concrete--can result in reduced quantities ofsteel and concrete. The reduced floor-to-floor height results in a smaller building envelopesaving exterior finish material and resulting in reduced energy usage for heating, ventilationand air conditioning. In parking structures, the openness of post-tensioned designs results inimproved lighting and more efficient energy usage and safety.

ConstructabilityPost-tensioning can enhance the speed of construction and overall constructibility. The useof PT in segmental and cable-stayed bridges has revolutionized long-span bridge

Figure 5: entrance area of Knowlton hall, Ohio State University


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Efficiency and Versatili ty of Post-Tensioning in Build ing Construction


construction and has enabled concrete bridges to be built in situations previously thought tobe impossible.

High-rise buildings can be constructed very quickly using post-tensioned concrete systems.Rapid floor construction cycles are achieved through the use of high early-strength concrete.

The use of standard design details of the post-tensioned elements, minimum congestion ofprestressed and non-prestressed reinforcement, and earlier stripping of formwork cansignificantly reduce the floor construction time. A 3-4 day construction cycle per floor iscommon.

Efficiency and Economy with Post-TensioningThe significant advantages of post-tensioning as compared to RCC construction serve tomake post-tensioning a very cost-effective structural alternativeboth in terms of initialconstruction cost and life cycle costs. With spiraling material costs, the desire to constructquickly, and the growing concern over energy usage and the environment, post-tensioning is

receiving renewed attention from many designers and discerning owners. Its use is limitedonly by the imagination and creativity of designers and contractors.

References1. Post-Tensioning Manual, 6th Edition, Post-Tensioning Institute, Phoenix, AZ, 20062. Collins, M.P. and Mitchell, D., Prestressed Concrete Structures, Prentice Hall, Englewood Cliffs, NJ, 1991.3. Lin, T.Y. and Burns, N. H., Design of Prestressed Concrete Structures, 3rd Edition, John Wiley & Sons, NY, NY,

1981.

PS: Artic le collected with the effort of Mr. Jyoti Shankar Pandey, Btech, 3rd year.

Seminar on Stress ManagementCES had organized a seminar which was led by Mohan Rupa Das. This seminar

had focused on a very common day to day problem of life- that of stress, and that isa part of academic life at IIT, especially near major exams. It not only spoils ourhealth but also kills our efficiency. However, through simple practice, stress couldbe kept at bay and life could be made happy and blissful. The seminar had thrownlight into how stress can be efficiently managed.

Workshop on Technical Paper PresentationFor the first time in the history of the CES, a workshop was organized for the firstyear students to teach them the art of writing a Technical Paper, and presenting it.Dr. Bhalla and Dr. K.N. Jha were the speakers.

Spotter

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Unrevealed Facts of 2007Statistical Survey...

Civil Engineering SocietyIIT Delhi, Hauz Khas,New Delhi - 110016

0

DCE Fest:Concrete Cube Designing (Runners-up)Amol Varshney (Btech II yr)

Vrinda Grover (Btech II yr)R.S.Sravan Kumar (Mtech)D.V.S.Rama Rao (Mtech)

Techincal Paper (3rd Prize)R.S.Sravan Kumar (Mtech)

Bending Moment (All India Civil Engineering Quiz)(3rd Prize)Anupam Mishra (Btech 4th yr)Nikhil Mahant(Btech 3rd yr)

Inter-College Technical Event Results


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Averages

Department : 6.44Boys : 5.46Girls : 10.91

*No girl has salary (ctc) lessthan the average Boys Salary

*All girls placed

Please Note that.

1. The data has not been collected from the official TnP sources, but our own efforts. Hence,this data might be different from actual TnP figures.

2. The Salary ranges are the Cost-to-Company. The inhand/basic salaries of lower CTCmight be same as that of high CTCs.

3. CTCs sometimes deceive students.4. As per TnP office regulations, names have been kept confidential.

5. Off-campus records not included

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2


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LIQUEFACTION HAZARD IN DELHIa technical report...

Hanumantharao. ChResearch Scholar, Department of Civil EngineeringIndian institute of Technology Delhi, Hauz Khas, New Delhi

ABSTRACT Evaluation of liquefaction susceptibility requires a reliable ground motion and athorough dynamic site characterization. In case of Delhi, the strong motion data available is scanty.In absence of a reliable pga, evaluation of depth of liquefaction using so called simplified methodis certainly questionable. Moreover, this method has not been validated in India. An effor t has beenmade in this paper to estimate the depth of liquefaction for clean sand using measured shear wave

velocities and reliable ground motions to find CSR. For magnitude of 7 and 7.5 earthquakes, thedepth of possible liquefaction is observed to be a maximum of 2 m, which increased to 4 to 6 m formagnitudes of 8 and 8.5. However, in Delhi, most of the areas, in general, the top 10 m of soilconsist of silt in excess of 20%. This will further reduce the liquefaction hazard.

1. INTRODUCTION

Soil liquefaction is a major concern for structures constructed with or on sand and sandy silt. Thevery recent Republic day earthquake at Bhuj in 2001 has again illustrated the significance andextent of damage caused by soil liquefaction. Currently the method proposed by Seed and Idriss

(more popularly known as simplified method) is being used in India to evaluate the zone ofliquefaction. Though the accuracy of this method has been verified in US and Japan, in our country,there is no well-documented case history to prove the efficacy of this method. The critical input toestimate the CSR (cyclic stress ratio) induced at any depth using simplified method is peak groundacceleration amax (pga) and to estimate the CRR (cyclic resistance ratio), the most critical input isthe Magnitude, Mw of the earthquake. These two quantities play a major role in evaluating the zoneof liquefaction, but these two quantities are the uncertainties exist in liquefaction evaluation forDelhi. Due to lack of strong database of earthquakes that occurred in Delhi, considerablejudgment is required in using this method. Though a large database of SPT data is available fordifferent regions, the quality of data has been a matter of discussion and concern. Another way ofassessing the liquefaction susceptibility is to use shear wave velocity, which is a basic engineering

property, than using an index property provided by SPT and CPT.An attempt has been made to ascertain the real liquefaction threat using the shear wave velocitymeasured and realistic ground motions provided by Singh et al., 2002. CSR has been calculatedusing wave propagation technique. CRR has been calculated using the methodology proposed byAndrus and Stokoe (NISTIR 6277, 1999).

Here, to capture a worst case scenario, a site in trans-Yamuana area (recent fluvial deposit) wherethe percentage of silt is less than 5% is chosen and shear wave velocities have been measured.

2. INPUT GROUND MOTION

Possible ground motions in Delhi from future large/great earthquakes in the central seismic gap ofthe Himalayan arc were estimated by Singh et al., (2002) using the seismic records (three on softand one on a hard site at Delhi) of the 1999 Chamoli earthquake (Mw 6.5, epicenter distance, ~300 km). The recorded motion on rock site has been used as an empirical Greens function (EGF)to generate ground motions for higher magnitudes. The ground motion data used as input motionfor magnitudes of 7, 7.5, 8 and 8.5 is shown in Figure 1. Peak ground acceleration (pga) on thebedrock corresponding to each magnitude is shown in Table 1.

3. DYNAMIC SOIL PROPERTIES

Spectral Analysis of Surface Waves (SASW) method, which isenjoying lot of popularity among the researchers andpractitioners alike, has been used for shear wave velocityp ro f i l i ng a t severa l loca t ions in De lh i . F igu re 2

Magnitudepga onBedrock

77.58

8.5

0.007 g0.015 g0.024 g0.050 g

Table 1: pga on bedrock fordifferent magnitudes

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4

shows the representative shear wave profiles measured for 15 m and 25 m depths of sandysoil (trans-Yamuna deposit). These profiles were used in the analyses by assuming clean sandwith no fines for getting a conservative solution.

4. GROUND RESPONSE ANALYSES

The response on the free field has been computed for 15 m and 25 m depths using the aboveinput ground motion in two different ways (Hanumantarao & Ramana (2004):

(c.) Input motionFigure 3. Input and free field response on top of 15 m deep clean sand profile for 7.5 magnitude earthquake

(b) Response on free-field when input motion

is used as bedrock motion

(a) Response on free-field when input motion

is used as outcrop motion

Figure 2. Measured shear wave velocity for 15 m,and 25 m deep clean sand deposits

Figure 1. Input acceleration historiesused in analysis


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15



(i) The object motion is with in the profile i.e., it is assumed that bed rock is below and(ii) The object motion is rock out crop i.e., the ground motion is recorded on the rock outcrop ina near by area. These two cases were considered because the depth of bedrock in Delhivaries from ground level to a few hundred meters with in a km span. Figure 3 shows the inputmotion and the computed free field response for a magnitude of 7.5, for 15 m deep soil profile.

It can be seen from Figure 4 that the simplified method over estimates the CSR induced in the

soil as compared to the wave propagation analyses using SHAKE 2000. This is even after thecorrection factor rd has been applied. This behavior is due to the fact that amax is assumed tobe constant through out the soil column. So, a more realistic approach would be to evaluate thevariation of amax with depth using wave propagation analysis


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LIQUEFACTION HAZARD IN DELHI

6

a technical repor t...


Figure 5 shows the CSR induced at different depths, using wave propagation analyses, for amagnitude of 7.5, when the ground motion is used as rock outcrop as well as bedrock motion.It can be observed that the CSR induced is significantly less when the ground motion is usedas rock outcrop as compared to using the input motion as bedrock motion. This is due to the

fact the pga becomes significantly less in the former case.

Figure 4. CSR from simplified method andwave propagation analysis

Figure 5. CSR for 25 m and 15 m deepsites (for Magnitude 7.5

Figure 6 shows the depth of liquefaction, for clean sands, for different magnitudes for a 15 mdeep profile. One can easily see that the zone of liquefaction is about 2 m for magnitudes of 7and 7.5 where as it is about 5 m for higher magnitudes. It should also be noted that when the

ground motion is used as rock outcrop, the depth of liquefaction reduces to about a metereven for higher magnitudes.

(a) Input as bedrock motion (b) Input as outcrop motion

Figure 6a, b. Depth of liquefaction for 15 m deep profile

IS 1893 2002 par t I gives a ZPA of 0.12 g for design in Delhi region, which is higher than that calculated valuesusing SHAKE. A close look at the codal provisions in this regard is required.


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LIQUEFACTION HAZARD IN DELHI


17

a technical repor t...

6. SUMMARY

The preliminary analysis indicated that: An accurate/reliable pga as well as magnitude is required for using the simplified method The uncertainties in these parameters will significantly influence the computed zone of

liquefaction A more rational method would be to estimate CSR using wave propagation analyses The choice of using the input motion as outcropping motion or motion within the profile

has significant influence on the computed CSR Using a pga as given by code of practice leads to higher depths of liquefaction The results presented here in assumed clean sand. Any increase in percent of fines will

lead to increase in resistance to liquefaction The results are based on strong motion records developed for earthquakes in the greater

Himalayan arc i.e., at epicentral distances of 300 km. Further work is needed to assess the effect of near source effects on liquefaction of

Delhi Silt Laboratory tests are under progress to corroborate these findings

lpa approx. The highest package for the Civil Engineering Student this year. All of

them being 7-pointers.

The number of students getting a core Civil Engineering job this year

The number of students placed till date (11/03/07) out of a total of 52 eligible

students.

lpa. The average package of the department students placed so far.

The number of 7-pointers who couldnt get placed this season. While this number isfor 9-pointers, for 8 pointers, for 6 pointers, and for 5-pointers.

students from the department got placed before 1st Feb. This number was last

year.

The number of 2003 entry students who went abroad for Summer Internships this

year.

The number of GRE candidates from the Department of Civil Engineering this year

The lowest CGPA of a GRE candidate

The lowest CGPA of a GRE candidate to receive the call for MS

The highest GRE score of two candidates this year The number of 9-pointers in 2005 entry batch so far

The number of 6-pointers in 2006 entry year students. Almost of the batch

strength of 74.

The number of 2006 entry students below 7 CGPA mark. Almost 69% of the batch

strength. This percentage is for 2005 entry, for 2004, and for 2003 entrystudents.

The number of House Secretaries from the department this year

The number of Representatives in various clubs from the department this year

The percentage increase in the batch strength of the department in 5 years.

The number rises from 39(passing out students) in 2002 to 74(current batch strength)in 2006. 73 is the stable batch strength of 2005 entry Civil Engg. batch.

15.2

639

6.44

01 1 3 7

36 19

19

185.66.33

1460031 42%

5160 53 49

31589.74%

Spot t er on F A CT & F I GU RE S of L ast Year


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contribution to society...

Ajit Kumar BhattacharyyaI.R.S.E. [Retd]

IntroductionIn the changing World Scenario Structural Engineer plays a leading strategic high- valued role in both design andprocurement of Construction projects utilizing their knowledge, expertise and experience. As Structural Engineers weshape the world that surrounds all of us. It is an International Science and ever-progressing technology. There is a

common understanding between structural engineers that many other professions do not have. Structural Engineer is an

important link in the chain of Mother Productive Construction Activity and contributes to the formation of assets of theNation, so vitally important for poverty alleviation amongst the masses. Such Engineers are responsible for the guidanceof public safety; make the structure stand safely, through a creative process, operationally and on long-term basis.People all over the world use structures like, houses, buildings, utility services, Water supply sewerage, power cables,Oil Pipe line, bridges, while using them want to be assured of safety. Structural Engineers design the muscles and

skeleton of the structure. Ethical foundations of profession and concern for human welfare were laid since the verybeginning of civilization. The talent of the structural engineers involved shines through the outcome. The Engineers needto provide assurance of their experience and updated professionalism to satisfy the public desire. Communicating thebasis of engineering judgment is the need of the day. Conversion of the basics of expert knowledge into technology,

which is simple, reliable, sustainable and flexible for solution of local problems with use of readily available resources, isthe process. The art of Structural Engineering can be deceptively simple. Unless we are prepared to contribute to thewider purpose within a situation we will continue to be marginalized as technical experts. As team players we have a role

in finding win- win situation for everyone involved. Importance of innovation and the challenges posed by the need forsustainable construction need be a part of overall plan. They have to debate about what is most efficient and

environmentally sound the structure should be able to produce renewable energy.Developing and evaluating dependable evidence on the basis of demonstrably assured and justifiable way are means ofpractice. They have to visualize the patterns of loads, which the structure must withstand and load paths, which conductthese loads through structure to the foundation, and to stable earth. The topics of internal force paths, internal forcedistribution and their influence on structural stiffness should figure strongly in his knowledge. Practical advice topracticing engineers to fairly judge the structural behavior will make them understand true engineering.

CharacteristicsWe need to be less nave in our expectation of what the society can do for us. Nations seem to encourage Engineers whoare articulate, innovative and commercially astute. Public does admire technological self- confidence. The professiongives excitement, imagination and youthfulness not related to age. It offers many challenges in the frontier of future

developments. They are needed for their practical rigors and society gets more by savings through adoption of an optimaldesign and execution method. They are leaders and managers, add value, and deal with facts, take decisions that work.

Being aware of the change in our business, of dif ferent ways of doing things and what can be done, we could improve theattention we give to the owner.

Upgradation of TechnologyRapid evolution of Construction processes and technological up gradation as now taking place is likely to change therole of participants substantially creating oppor tunities and warnings systematically for future development. Danger ofconcentrating much on the Calculations and numerical parts of the design are failing to develop the conceptual skills and

ensuring link to efficient process at site is equally vital. Built environment is identified as Key Area. Essential and radicalchanges are needed to meet aspirations of the people One must be far more aggressive in the market place to ensurethat clients understand difference between Quality Service and Average service. Increasing the professional Identity and

telling clients we are the greatest, not hiding from reality should be the criterion. Quality is a fitness for purpose with adegree of excellence

Importance of DesignPlanning and Design is the basis of all Engineering This demands functional efficiency with economy, enduring visualelegance under challenging circumstances, containing intellectual logic, achieving social and environmental congruity,durability and low maintenance cost, capable of being constructed with ease and speed, - significantly much more thanmere analysis. When good design is demonstrated with quality control it is well appreciated Design at its best

incorporates attention to the interaction of structures with services and finishes, its environmental setting as well asstructure itself. For the sake of his career a structural engineer must assure reliability of the structure.For durability and good performance in maintenance, design and construction engineers must take precautions ofprotection and detailing of the reinforcement bars, in addition to the design considerations. Structures subjected to

dynamic loads such as gust wind, cyclonic weather and earthquake undergo repeated reversal of stresses. Lack ofproper reinforcement detailing and enforcement of quality assurance lead to disasters. Reinforcement is required for

protection against cracking and also provides ductility to the structure. Location of laps and splices,


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required for protection against cracking and also provides ductility to the structure. Location of laps and splices,curtailment of the bars are important from strength point of view, durability and construct ability angles.

Existing StructuresStructural Surveys are not proper engineering but real Engineering in the true sense and best equipped to do so are

structural engineers. It is essential to know / understand as to how buildings/ structures behave compositely undervariety of conditions they are expected to experience in their life cycle. Assessment of repair to damages systematicallyis the first step before elaborate repairing schemes are to be formulated. Proactive asset management requiresinformation on the state of the structure and this is changing over time. Continued research undertaken has establisheda common point in the loading unloading cycles beyond which the structure is not economically sustainable. FewInstitutional courses deal with the challenge of dealing with existing buildings requiring rehabilitation/ renovation.Examination of failures are remarkable source of experience for those who are engaged in the course of their career- thestudies reveal the reality of human frailty which forms a salutary and perhaps alarming lesson- in the context of publicsafety. Recent trends on maintenance, repair, retrofitting and monitoring of structures should be assessed and reviewed.Health assessment periodically and inbuilt monitoring of Structures from durability/safety consideration by experts hasto come into existence.Development and Calibration of instrumented inclusion acting as Stress- meter, bonded with existing structure toestimate the level of residual stress and prestress in the body has opened wide horizon in declaring the in state condition

of the same. High frequency piezoelectric signatures for diagnosis of seismic/ blast induced structural damages arerecent tools to help monitoring of distressed structures. Consequent on the development of the know-how of Externalprestressing provision for future prestressing during the construction to impart same to counter distress, such as,cracking, excessive deflection etc at a future date. Sound judgment is more important than playing with the technicalgadgetry, with an element of risk involved in most engineering decision.Engineers should be capable of developing a qualitative Bending moment and deflection diagram with a clearunderstanding of structural behavior instead of totally being dependent on software and use of computer.

Managing StructuresStructural Engineers have an important task in managing existing structures, drawing upon the skills and expertisecomplementing the work of the building maintenance team besides creation of structures. The management ofstructures requires special supporting skills and knowledge which aspect is under developed. An appreciation of inservice good structural order performance is required for the whole life design of new structures. Knowledge on best

practice performance in this increasingly important area of activity is to be gathered. Processes, activities necessaryformulated. The aspect developing quickly is the design of structures against fire resistance with advanced analyticalmethods and improved risk assessment techniques

Competitive EnvironmentKnowledge Economy, requirements of Social Accountability and the insistence on sustainability will force continuedchanges and may possibly accelerate the process. The Engineers are to organize against the turbulent forces of newworking practices, new way of material management, and demands of performance along with technological innovationkeeping balance with economic agencies which place a premium on ethical practices. A strategic view of the futuretrends identification based on systematized data collection is necessary .to anticipate changes and manage themeffectively. Creativity is a culture and out of creativity comes competitiveness to withstand economic and environmentalchanges.

Past DevelopmentThe existing heritage structures of India are all of immense intensive structural intricacy and marvels of conception,innovation. From prehistoric days when primitive implements were used for agriculture and small-scale industries, designof country boats, the structural engineer contributed his mite to evolve the process of effective use of natural materials,making it stronger and stronger with passing time. They realized the condition of stability of the structure through study ofNature and developed mathematical sciences. Nature has always been an inspiration to designers. Biology [biometrics]is to be next engineering science. In the field of modern medicine structural mechanics has an impor tant role. We shouldlook inside our own bodies to seek openings for innovation of structural mechanics Structural Engineering helps todevelop the understanding of human frame dynamics, useful in sports and making of artificial limbs. Engineering ishaving a major impact on the biological sciences understanding. In recent times none can overlook the contribution ofstructural engineers in the modern technological field of aviation, navigation, rail- road transit systems and surgicalinputs for replacement of worn out human body joints.

Creativity/InnovationManaging Creativity requires a tolerance for ambiguity and for the unexpected and readjust accordingly .We are


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more at ease in taking risks and to prototype endlessly. Innovation is a primary focus for all Engineers and will remain soin the foreseeable future to deliver better products, source of competitive advantage and opportunity, to provide benefit tothe customers and society through a truly creative solution and revolutionary design. It is facilitated through a blend ofmethodologies, work practices, a supportive culture and right business infrastructure. We should develop a positiveattitude that we are vital part of the society and put in efforts to empower, energize, enable and ennoble society through

selfless service. Crucially, risk takers need to balance nerve with creativity. Innovation is the driving force to overcome allthe site problems. Using Computer enabled understanding of theoretical models, allowing much more to think aboutvariables, the present-day Structural Engineer are better equipped to take up assigned job. They are in a position toconvert a 2- dimensional object with 3 dimensional one in their vision. Drawing is the language of Engineers andperfection in this art is essential for a successful one.The knowledge for implementation of new procedures, advanced analytical methods and improved risk assessmenttechniques to support performance design for Fire-load case tends to be in the hands of a few specialists and to bespread amongst a wide range. Numerous are the examples of successful adoption of Innovation in StructuralEngineering which is practiced by all aspiring engineers maximize the productive capacity and we become the mostefficient, technically aware, practically minded professional. Structures that adapt to changing forces and circumstancesresulting in forms that are tolerant and hence robust-the structures that we build have a marked impact on oursurrounding. We strive for structural efficiency and excellence .Let us expand our horizon and move forward with prideand confidence in this fine profession of ours.

Changing use of MaterialsThere is need to choose materials on the basis of a wider set of criterion in technological, energy consumption,renewability and recyclables. Selection of Materials that can be formed and placed ensuring safety of operation and endcost is a challenge to the engineers. Resort to expensive alternatives to conventional reinforcements should be done onlyon reasoned basis and absolute requirement. Optimum use of resources physical, financial and human is adetermining factor in raising, expediting the rate of growth. Exploitation of abundant natural resources to productiveadvantage must be resorted to. Revolutionary Nano-Technology may change the entire scope of established designpractices through adoption of new lighter /stronger materials and consideration of structural behavior. Reluctance toaddress issues relating to good concreting which is fairly basic but requires obligatory site supervision rather thanunnecessary initial capital expenditure by use of many claimed quality reinforcing bars, to be banished. It would be surelyof more lasting benefit to depend on skilled trained manpower and produce by tested practices High-performanceConcrete. The high grade concrete structures used in Bridge decking regular behavioral survey need be excercised

regarding micro cracking and alternative solutions should be evolved. Before specifying use of FBEC, Stainless Steel orFRP avoidable deficiencies in site workmanship must be attempted. They must be confident of producing structures ofreliable strength and durability. Many investigation reports on existing structures point to the deficiencies in our system.and must be dealt with.Without advanced FE analysis and improved weldability of steel the construction of many large structures would not befeasible to day.

Application of ICTIncreasingly the focus on use of IT will be a co- coordinated knowledge management tool across the profession, toimprove quality of the process not just economy. Enhancement of Technological Literacy through setting up ofinformation clearing houses with directed basic, applied or development works details covering domestic and foreignknow how an issue to be seriously considered is. This allows even small group of people make independent enterprisesand takes up technology interesting, challenging. The use of computers has revolutionized finalizing structural detailsinvolving non- linear and dynamic effect analysis. The designers should however have more understanding of structuralbehavior than the in the past when worked manually. Relatively cheap powerful desktop computers are nowcommonplace and finding a profound influence in our profession. Modern development in software and hardware offerlimitless possibilities in its application on Engineering and potential development is inconceivable.

Continuous Professional DevelopmentPublic policies and market forces linked to environment protection, social equity and economic viability will graduallytransform the development position and redefine social progress. Professionals have to act professionally and sharetheir knowledge experience to further their role as a learned society for the benefit of fellow beings. The rules of conductand ethics of profession need to be enforced at all levels. CPD does not have to be restricted to attendance of coursesbut includes work shadowing, structural research to an objective goal, in- house training, IT skills development,mentoring young engineers, management training, careers talk and activities in professional Institutions etc. News letters

from CROSS regarding experiences on Safety and discussions through forum like SEFI are useful tools to developprofessional knowledge.


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Engineering Council Of Indias efforts in this direction for enforcing Continuous Professional Development andProfessional Registration is laudable. Local authorities controlling building standards need to exercise greater emphasison strict compliance with sincerity and integrity, the quality of construction and observe statutory obligations. NaturalDisasters experienced in the country has exposed many shoddy constructions with poor professional handling. Newgeneration codal provisions, Microzonation work undertaken for metropolitan cities, Base isolation processes evolved

are a guide to earthquake resistant structures. Training of the large body of engineers to understand the implications is astep in the right direction, to be pursued. Expert committee repor ts on after Tsunami effects or Seismic damages in Indiamust be gone through with care and recommendations applied in practice..

Certain Caring i ssuesThe highest state of expertise is recognition of interdependence and that depends on shared values, which are based onethics and expressed through rules of conduct. Looking for unintended consequences is an important idea in theprocess of risk management. Considering the whole as well as the parts, connectivity to the entire process links, creatingappropriate models, using systems highly interconnected and processes which are part and whole of interdependence,making prompt judgments, exercising creative foresights, feedback and learning are important process of experthandling and resulting success.The availability of sophisticated FE packages has enabled engineers to push the frontiers further in adopting newconcepts and be forward looking possible.

Effects on Structures [Unusual Causes]Climate change due to global warming is to be assessed. This is attributed to natural or Man made influences. This maylead to great number of extreme events and cause great severity. There is a large margin in our quantitative assessmentof the likely effects, climate changes on the exposed structure magnified by non-linear response system. A properunderstanding of the effects of factors such as prolonged exposure to high intensity wind speeds along with highfrequency extreme gusts, extreme precipitation leading to flooding and scour [erosion resulting from the shear forceassociated with flowing water and wave- action], the ability of Bridge piers to withstand super-floods and the influence onfoundation of accelerating, more severe shrunk- swell behavior, subsidence caused by ground changes as a result ofprolonged dry- spells or droughts, behavior of clay-soils, which change volume as the moisture rises and falls withconsequent potential moisture deficit, are important factors for consideration. People dealing with structures mustunderstand must understand what toxicity of Standing Water can cause to a structure remaining under submergedcondition for days as experienced recently in Mumbai/Surat and several other places.

Understanding of likely future climate, extreme diurnal temperature changes and its influence on key structure-response, periods of drought and high temperature leading to ground movements and to make necessary provisions towithstand the effect, Warmer and wetter climate, higher sea levels, increase in gale-frequencies, greater probability ofstorm surges are the predictions necessitating more call for flood defense schemes built to offer increased levels ofprotection, Effect of typhoon loading on cumulative fatigue damage assessed by the time period of stress spectrumincluding potential severe effects on such situation are important consideration.Possible changes in the level of degraded environmental design loadings, alteration in the mix of construction and tocertain extent the features present, greater awareness and sensitivity over climatic issues, contaminated surroundings,influencing design choice should be thought of.Experience has shown large number of habitats has crumbled at the time of earthquake mostly due to poorworkmanship of construction, detailing, material used and design by ill-informed architects/ engineers. Extra provision atcorrect location has to be made to limit damage Post earthquake management, inspection and restoration measuresneed to be gone into more seriously. Ill effect of tidal wave in uplifting of badly detailed Bridge Girders and gale storm inuprooting of incompetent poor design of transmission line towers are often witnessed. Forces of nature like earthquake,landslide, and floods sometimes get the better of us we have to be sensitive and respond to them adequately throughadoption of upgraded technology. Structural Engineers competence will be necessary for early restoration measuresplanning and execution both as short time and longtime way which will be of considerable importance in alleviatingsufferings of the country men Monsoon reserves including demountable light weight high strength structures are to bekept at specified location under charge of Inspector at workshop earmarked for emergency works for speedymobilization and execution of works. Advance action for prevention and preparedness for various possible NaturalDisasters of different regions needs to be engineered with definite action plan. Regular Drilling of action plans will go along way in prompt restoration.

Case Stud iesA] Land SlidesChakki Hills short of Pathankot, toe of unstable hillock, land slides in monsoons blocking both rail and

road traffic due to falling boulders and soil erosion getting hardened after draining. Many remedial measures andpassage of time before slides reduced. In tunnels approaches land slides and heavy seepage through joints causesdisruption of traffic of long duration.


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B] FloodsBridges generally constrict the flow of water and can act as artificial dams of debris jams on the structure. High standardHydraulic characteristics must be considered at the design stage to prevent an unacceptable rise of water levelsupstream of the structure and withstand extreme events. Bridges are important in terms of maintaining access for

evacuation and delivery of medical and other emergency services.

1] Intensive rainfall in 1962 Firozpur, important border town was cut off from 3-sides due to floods. Important wideRajasthan Canal under Construction high banks cut by villagers to save themselves caused scouring locally of pier- wellfoundation. Temporary waterways had to be kept at select locations to save important installations while resumingthe traffic.

2] Pathankot Jammu line Basantar river having a flat slope with rising river bed, floods in 1977 caused breaching ofhigh embankment on the approaches causing strategic disturbance.

3] Laksar- Dehradun section Motichur river inundated due to aforestation on upstream neglect of dismantling theabandoned causeway and non appreciation of effect of the newly constructed downstream road bridge to existingrail bridge caused oblique flow of water and scouring of open pier foundation greatly.

4] Lohand Khad-Ropar- Nan gal Dam Section Continuous flow of heavy silt free discharges effluent from a newlyconstructed Power House on up-stream and during receding monsoon, oblique flow caused settling of piers due to

scour on open foundation with flooring, resulting stoppage of power house

5] Degana Ratangarh section of Rajasthan- changes in the sand dunes on upstream due to wind effect, oblique flowcaused instability of piers resting on shallow open foundation due to scouring6] Harike Barrage under construction on upstream of Delhi- Rewari line caused diversion of natural flow of rain water

away from openings provided in the railway line and sudden letting out of accumulated flood water downstreamcaused extensive breaches on the approach banks far away from the designated openings. In the case of old tunnelswith heavy concentrated rainfall considerable seepage of water and occasionally falling of portion do take place.Localised cement pressure grouting was used for restoration purpose.

In all these emergent situations vigilant patrolling Gagmen prevented any mishap. Well-drilled and tested restorationmeasures designed to suit each local conditions and devoted set of workforce helped in bringing traffic flow although

with restriction in the shortest possible time. The river protection works needs to be kept under constant vigil by postingstationary patrollers and keeping in stock restoration materials as also access ways, as meandering of river flow is itsbasic nature Colcreting of existing damaged flooring of Bridges has been used to prevent unsafe scour of existingshallow foundations. We have to undertake systematic study on protection measures and foundation depth to be

provided in a country with varying conditions of base materials/ and sizes. Demountable flood defense structuralsystems both on permanent and temporary basis to protect valuable properties and life against rising water is beinginstalled in European Countries as against humble Sand wallings. This development has tremendous potentiality in theingenuous handling of selection of materials by Structural Engineer.

Transmission line towersWeak design of transmission line towers not catering to severe gale storms resulted in collapse of 2 towers at Khurja and

Moghalsarai of Delhi-Kolkata trunk route causing disruption to communication system. The structures were redesignedand where feasible rectification works done indigenously in addition to laying strict maintenance schedule. The structureearlier erected was fabricated according to design made and certified by a turnkey developed country firm of standing.Technology intervention is essential to solve/determine1] Disaster risk and working out mitigation methodologies

2] Experimental Simulation facilities for all hazard types to be created3] Active/ passive control systems to be promoted for structures

ConclusionThe use and development of technology must relate to the peoples aspiration. Our own immediate needs in India are theattainment of technological self-reliance. In a developing country this characteristic cannot be overrated. - This is the keyin which has the potential to usher the country to an era of prosperity- with other factors like materials and capital havingtheir relative importance. We have to broaden our service-base and look to provide added value forms with foresight and

competence. Not only the profession should grow and prosper but should be alive to the needs of the Nation. It is theresponsibility and obligation of every society to educate and train its young people to the highest standards for its benefitand development. Engineers must rise to the pressing demand in their role for alleviation of poverty, especially in the ruralareas through infrastructure development and other associated productive works. Emphasis laid on development oftransport sector gives opportunity to the engineers to show their worth for improvement of countries economic prosperity,

remove general poverty. The write up is based on my personal experience spanning over five decades, discussion withmany stalwarts in the field and my systematic study of published literature on the importance of our profession where weproudly belong. I acknowledge with gratefulness any similarity of thought as expressed anywhere by fellow engineer.


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We make our world significant by the courage of our questions and by the depth of our answers. - CarlSagan

Picture this A young civil engineer who has graduated recently, or one who is on the threshold ofgraduation with a bagful of dreams, hopes and ambition. When the actual planning for the future

commences, the young professional finds himself at a loss with the array of options and questionsthat stare him in the face. Does he/she start working right away? Does he/she study further? Whatdoes he/she have an aptitude for? What will be lucrative and at the same time satisfying in the longrun?

Now consider this scenario: A common platform connects the student fraternity of civil engineersacross our country. A platform or a forum that helps them keep in touch with what is happening indifferent colleges; exposes them to the conscious choices being made by their peers; that helps themanswer their queries and make their decisions. This platform could extend to interactions withprofessionals in different parts of our country and to opportunities across the borders. Such anetwork would certainly facilitate easy dissemination of information and help build confident

professionals who have been awake to the situation outside right from the time of joining the graduateprogramme.

Ethos is an organisation that has taken a first step in this direction. The initial effort is being focussedtowards uniting the colleges in different parts of the country under one umbrella. Realising themagnitude of this task, Ethos has chosen to engage these young minds in some friendly competitionas a means of bringing them together. Hence Bending Moment! Ethos launched Bending Momentthis year A National Quiz on Civil Engineering with the intention of igniting the minds of budding civilengineers on engineering and construction knowledge that is beyond the classrooms. The zonalinterfaces are conducted at various centres and this is capped by a National Finale.

While Bending Moment aims at spurring the civil engineers already keen eye into observing andimbibing, Ethos intention is to go beyond and direct the enthusiasm that it has generated even fromremote nooks and corners of India positively towards fostering a national interactive platform thatwould serve the very purpose of equipping young professionals to be agents of change; to lead andnot just follow and to contribute positively towards the building of a harmonious society. It is fortunatethat institutions such as IIT, Delhi and CET Bhubaneswar played host to this event this year. The CivilEngineering Society of IIT Delhi can play a crucial role in making this National Platform a reality.

Whereas this is its first foray into the arena of civil engineering, networking students is familiar terrainfor Ethos. Ethos commenced its journey four years ago with Archumen Indias Biggest ArchitectureQuiz for students of architecture. Once Archumen gained in popularity, Ethos also went on the

challenge the creative prowess of these students through design competitions like Transparenceand the IGBC Green Design Competition. These contests gave the students an opportunity toassess themselves against the best in the country. More importantly, it also helped network on adifferent level. Archumen also travelled to Sri Lanka this year where an edition was held in Colomboand The Grand Finale of Archumen will also see a team from University of Morutowa in Colombomatching their wits with their Indian counterparts. This will also be an opportunity for the network totranscend across the borders.

For Ethos, launching of Bending Moment had a two-point agenda. One was definitely to reach out tothe civil engineering student community as well; the second was to bridge the gap between thearchitectural fraternity and the civil engineering fraternity. One needs to understand that these two

fraternities, in reality complement each other and one is incomplete without the other. One is notmeant to be competition for the other. Hence, Bending Moment and Archumen are held at the samevenues to facilitate some cross-learning and interaction

Connecting Civil Engineers

Gita Balakrishnanmain mover behind Ethos

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to reach out to the civil engineering student community as well; the second was to bridge the gap between the

architectural fraternity and the civil engineering fraternity. One needs to understand that these two fraternities, inreality complement each other and one is incomplete without the other. One is not meant to be competition for theother. Hence, Bending Moment and Archumen are held at the same venues to facilitate some cross-learning andinteraction.

Ethos is exploring alternatives by which there can be regular dissemination and sharing of information onopportunities for training and work, on national level and international level competitions etc. Students should beable to get in touch with other students across the country with similar interests. Young professionals who are

part of the network could guide aspiring professionals on fields of further study or training opportunities.Projects of young students, innovations etc., could also be shared which would work to the benefit of the authorof the work as well as the reader. There would also need to be an active interface between the industry and thestudents which is essential for a healthy development of both.

Ethos has already commenced networking opportunities with young architects and students with a specificintention of matching interest and aptitude with opportunity since this is a prime concern in a field such asarchitecture. Ethos proposes to intensify this effort and extend the same to the fraternity of civil engineers. This

aspect assumes special significance in view of the fact that there are a very few companies/organisations thatare identifying prospective employees through the typical process of campus interviews in the field of civilengineering and architecture.

For such an endeavour to succeed, students, faculty members, institutions and professionals would need to playa proactive role. Colleges and faculty members would need to encourage participation from their wards. Theycould also par ticipate by reverting with regular feedback and suggestions on ways and means to improve. Theresponse in the first year of Ethos has been extremely encouraging on all fronts and portends the realization of

the set goals.

Coming together is a beginning. Keeping together is progress. Working together is success.-Henry Ford

.. And the Third Prize goes to . IIT DelhiThe Northern Interface of Bending Moment resulted in Abdul Mujeeb Mohammed and Tarun Bansal from IITRoorkee taking the first position in the first ever National Quiz on Civil Engineering. The first runners-up wereKarn Agarwal and Sudheesh Kumar again from IIT Roorkee with Nikhil Mahant and Anupam Mishra from IIT

Delhi, the home team taking the third position. The other teams that reached the Nor th zone finals of BendingMoment were from DAVIET, Jalandhar and Delhi College of Engineering.

Seminar on Risk ManagementCES had presented a Seminar on The Risk Management of Risk in Private Funded International

Infrastructure Projects by Prof. Simon Burtonshaw-Gunn. The seminar had begun with a look at therelationship between construction and risk management and then considered the options for privateinvestment in infrastructure projects. The role of the Prime Contractor had been discussed and howrisk management plays a crucial part in selecting potential projects, particular those at internationallocations.

Seminar on Model Based EngineeringA Seminar was presented by CES on Model Based Engineerig Advantages & Challanges. Thisseminar was led by Prof. Dr. -ING. Raimar J. Scherer, Director, Institute of Construction Informatics,University of Technology, Dresden, Germany. It helped in providing the vision of the Building Model,Integration and Interoperability, Collaborative Working, Comparing Algorithms Detect DesignChanges,Mobile Based Working using BIM.

Connecting Civil Engineers

Spotter

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ASSESSMENT OF RISK

Manaswini Behera & Subrata Bhattacharjee2nd year MTech,Environmental Engineering and Management

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envri onmental engineer ing

Assessment of Risk due to Intake of Groundwater Contaminated with Heavy metalsat some places of West Bengal, India

AbstractVarious heavy metal concentrations has been collected in a number of contaminated groundwater samples of West Bengal, India and associated health risk due to ingestion of thesechemicals has been calculated. Noncarcinogenic risks attributable to ingestion of heavymetals for exposed population are not very high, whereas the mean carcinogenic riskestimate for arsenic is found to be very high. The population of this area is liable to arsenicpoisoning. As groundwater is the main source of drinking water for this area proper preventivemeasures should be taken to control this contamination and save the population.

IntroductionGovernments and industry have failed to control the spread of dangerous chemicals aroundthe globe.Manmade hazardous chemicals are so widespread in our environment, in our

homes and in the products we use everyday, that we are constantly exposed to pollutingsubstances. As a result even our own bodies are contaminated.A study by The British Medical Journal says that 75 percent of most cancers are caused byenvironmental and lifestyle factors. A report by the Columbia University School of PublicHealth estimates that 95 percent of cancer is caused by diet and environmental toxicity; inaddition, most Americans have between 400 and 800 chemicals stored in their bodies,typically in fat cells( Haris,2003).Water, air and soil quality are issues, which affect the quality of our food, health andenvironment in general. Growing levels of pollution and over-consumption of resourcesdemand some sort of solution. Anthropogenic impact on natural environments and especiallyon aquatic ecosystems is currently a topic of increasing concern. Deterioration ofgroundwater quality has recently observed in many aquatories (Boehm et al., 2002; Campoloet al., 2002; Jain, 2002; Nobukawa and Sanukida, 2002; Tara et al., 2003). The potential causesof such a situation are various sources (Duda, 1993). Most of these sources lead to thepollution of groundwater. The quality of groundwater may vary depending on the geologicalmorphology, vegetation and activities in the catchments, as well as on the location of thesampling site. Heavy metals cause a wide variety of adverse health effects.The term heavy metal refers to any metallic chemical element that has a relatively highdensity and is toxic or poisonous at low concentrations. Renowned medical journalist Dr.Morton Walker, D.P.M. writes, The ingestion of toxic metals destroys the brain tissues andnerve cells by increasing cellular membrane permeability, allowing for leakage of nutrients

out of the cells, and inhibiting enzyme production which, in turn, depresses the bodyschemical reactions. There will be lowered energy in all physiological parameters so thatchronic fatigue of the downhill syndrome becomes inevitable(Haris, 2003).Ingestion of drinking water containing heavy metals may lead to liver and kidney damage,immune system, nervous system, and reproductive system disorders as well as several typesof cancers. Toxic Heavy Metals are well known pollutants from both natural andanthropogenic sources. Their deposits in solid or liquid solutions have several ways to spreadout (including both physical and chemical transformations) and thus to get into the tropicchain.Risk assessment is a statistical tool used in conjunction with actual data to estimate potentialrisks to human health and the environment. Baseline risk assessments assume that noremediation actions are undertaken and assess current and future risks from thecontamination.


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contamination.

Study Area

Arsenic contamination of groundwater in catastrophic proportion has been reported from WestBengal, India (Mandal et al., 1996) and Bangladesh (Dhar et al., 1997). Various other metals are

present in the ground water of these areas.

Data of heavy metal concentration in ten ground water samples has been collected from differenttube wells in the Deganga block of North 24 Parganas district of West Bengal, India (Maity, 2004). Thevarious heavy metal (As, Fe, Mn, Zn, Cd, Cr, and Se) concentrations at different sampling sites areshown in Table1, Appendix I. It has been found that arsenic concentration is very high in these watersamples. This is due to natural arsenic pollution from arseniferous belts in specific geo-morphologicalconditions. Other metals like iron and manganese are also present in high concentrations at someplaces. The total population of this study area is 33,068 as per census,2001.

Effect of Heavy metals on Human health

There are three primary areas affected by heavy metals in our bodies: The nervous system, thecardiovascular system and the immune system. When these substances are constantly present, ourbodys natural detoxification systems become less effective. In fact, the ability to remove thesedangerous toxins becomes diminished and they are stored in adipose (fat) tissues. The EPA states allhumans harbor chemicals (Haris, 2003). The ill effects of various heavy metals found in the study areaare listed below.

Arsenic (As)

About 80% of the absorbed arsenic gets distributed in the tissues including liver, abdominal viscera,bone, skin, hair and nails (Browning, 1961). The health effects that result from the ingestion of arsenic-contaminated drinking water manifest slowly. Arsenic is considered a silent pollutant since there isgenerally NO smell or taste associated with its presence. Arsenic poisoning can easily go undetectedbecause many of its symptoms are also indicative of a number of other illnesses.

Health effects from arsenic exposure include skin damage, circulatory system problems and anincreased cancer risk, especially the skin, bladder and lungs. Early warning signs may includestomach pain, nausea, vomiting, diarrhoea and numbness in extremities.

Iron (Fe)

Anaerobic ground waters may contain iron II at concentrations up to several milligrams per litrewithout discoloration or turbidity in the water when directly pumped from a well. Taste is not usuallynoticeable at iron concentrations below 0.3 mg/l. Although iron has got little concern as a healthhazard but is still considered as a nuisance in excessive quantities. Long time consumption of

drinking water with a high concentration of iron can lead to liver diseases.Manganese (Mn)

Exposure to manganese and compounds may result in noncancer health effects. The probable routeof human exposure to manganese and compounds is by ingestion and inhalation. Short-termexposure to manganese may cause irritation to the eyes, nose, throat, and respiratory tract. Long-term exposure to manganese may affect the central nervous system, causing a psychosis which mayinclude symptoms similar to Parkinson's disease (gait, balance, posture disturbances, tremor, andfacial rigidity) . The International Agency for Research on Cancer has not classified manganese as toits carcinogenicity (IARC, 2005).

Zinc (Zn)

The most sensitive effects of oral exposure to excess zinc in humans involve the copper status of thebody. Zinc exposure can result in a decreased absorption of copper, leading to low systemic



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levels and subsequent health effects, including decreased copper metalloenzyme activity,hematological effects, and decreases in cholesterol levels, immunotoxicity, andgastrointestinal effects. While changes such as decreased copper metalloenzyme levels maynot be adverse in themselves, they have been demonstrated to be precursor events for more

severe effects. Under the Guidelines for Carcinogen Risk Assessment (U.S. EPA, 2005), thereis inadequate information to assess the carcinogen potential of zinc, because studies ofhumans occupationally-exposed to zinc are inadequate or inconclusive.

Cadmium (Cd)The biological half-life of cadmium in humans has been estimated to range from 10 to 30years. Cadmium has moderate acute toxicity, producing gastrointestinal or pulmonaryirritation effects from ingestion. Sub chronic and chronic exposures to cadmium have beenassociated with renal, cardiovascular, endocrine, hepatic, bone, hematological, andimmunological effects. On long term exposure it accumulates in liver, kidneys, pancreas, andthyroid. It also causes hypertension.

Chromium (Cr)Chromium compounds are corrosive on tissue. Long term consumption may lead to skinsensitization and kidney damage.

Selenium (Se)Long term exposure to Selenium leads to red staining of fingers, teeth, and hair, generalweakness, depression.

Results and Discussions

Risk due to non-carcinogensThe environmental risk to the populations from these elevated levels of non carcinogenicmetals in groundwater has been evaluated by first computing the mean estimated total dailyintake (TDI) of each of these toxicants (individual metal) using equation (1) (Singh et al.,2003).

TDI (mg/day) = CD (1)Where C is the mean concentration of individual toxicant in groundwater and D is the meandaily intake of water by a person.The computed TDI (mg/d) values for each toxicant are then compared with their respectiveacceptable daily intake (ADI) values (mg/d), worked out from their individual ADIs (mg/d/kg

bw) as available in the literature for a person of 70 kg body weight. The risk quotient (RQ) foreach toxicant was computed using equation (2) (Singh et al., 2003).RQ=TDI/ADI (2)

Risk due to carcinogensThe lifetime environmental risk to the populations due to carcinogenic metals has beenevaluated by using equation (3) (Singh et al., 2003).

Risk = Chronic Daily Intake (CDI) * Potency factor (3)The computed results are presented in Table2 and Table4 in Appendix I of this paper.As a general principle, the population exposed to some particular toxicant (chemical) will be atrisk with respect to the toxicant, if the value of the respective risk quotient (RQ) is above 1.0.However, if we compare the two population groups for their relative risk with respect to some

common toxicant to which these are exposed, their respective RQs may give an assessmentof their relative risk level for that particular toxicant (Singh et al., 2003).It may be noted that for any of these metals, none of the populations is at significant


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Manaswini Behera & Subrata Bhattacharjee2nd year MTech,E

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