Disaster Resistant Design and Seismic Strengthening of Buildings

Workshop on Preparedness and Mitigation for Earthquake Vulnerability in major cities of India

7th-8th July, AhmedabadAlpa Sheth, Seismic Consultant

VMS Consulting Engineers

Background

26 January 2001 earthquake exposed serious flaws in man-made constructionsProblems at all levels: Lack of competence (knowledge) Lack of motivation for proper engineering and

construction Lack of awareness about codes and seismic

requirements Lack of monitoring mechanism Lack of punitive measures

A classical example of systems failure

StakeholdersBuilderGovernmentContractorStructural engineerConstruction engineerArchitectMunicipalities, Development Authorities….MasonsPublic

Why is seismic engineering not widespread?

•Not taught in engineering colleges •Pace of change.

•First strong ground motion recorded was only recorded in the 1930s. •Seismic codes of the ‘60s, rather simplistic. •Rapid pace of research and availability of computers have added tremendous sophistication to the subject. •All this has happened in just one life time!!!!•Few working engineers outside Universities with the time or inclination to keep up to date.

•Cannot be practised as from a recipe book as complex concepts and mathematics involved.

Why is seismic engineering not widespread?

Seismic Engineering very different from regular structural design

In regular structural engineering design such as for gravity and wind,

•Check the stresses in members and determine acceptability by a basic criterion such as actual stress < permissible stress.

•Not so straightforward in seismic design!!

In earthquakes, structures designed for only a fraction (fifth to a tenth) of the seismic forces they can be actually subjected to.

•To ensure safety, the structure is to be specially detailed for ductility so that the structure can undergo large deformations without total collapse.

“In dealing with earthquakes, we must accept the probability that failures will occur in the near future otherwise all the wealth of the world will prove insufficient to fulfill our needs: the most modest structures would be fortresses. We must face uncertainty on a large scale for it is our task to design engineering systems – about whose properties we know little - to resist future earthquakes and tidal waves - about whose characteristics we know even less” (1971)

- W. Housner

•The seismic engineer is concerned not so often with preventing minor damage in moderate and severe earthquakes as he is with preventing total collapse so as to protect life.

•This means that for design of structures, there is a wide choice of design acceptance criteria, all with implications for damage and loss vs cost. “PERFORMANCE BASED DESIGN”

•Getting to be very popular in developed countries

A. Competency Building at Education level • Earthquake Engineering Education in Colleges • Training of Teachers to teach earthquake engineering

B. Competence Building in Practice of Seismic Engineering • Training of Practising Engineers • Training of Government Engineers • Mason Training and Certification

C. Awareness of Codes and Seismic Requirements • Review Earthquake codes • Home-Owner’s Guide to Earthquake Safety• Small Buildings Code

D. Monitoring Mechanisms• Comprehensive Review of Drawings by Municipal Authorities for

earthquake code compliance• Licensing of structural engineers through competency tests

Capacity Building in Seismic Engineering

Workshops held with all universities and Polytechnic Cell of Gujarat to discuss introduction of earthquake engineering education.

Based on consensus report of the workshops, it was decided to change the syllabus to incorporate earthquake engineering.

Detailed study was undertaken to ensure that students were not overburdened- meant overhauling of obsolete topics.

Curricula formulated for all the programs for seismic engineering for Degree, Diploma and Master’s level programs again through workshops and discussions.

GoG issued a GR to change syllabus in civil

engineering colleges accordingly in Polytechnic

Colleges, Degree & Post-Graduate Colleges

Capacity Building at Education level -Earthquake Engineering Education in Colleges Development and Implementation of Revised Curriculum in Engineering Colleges

Curriculum changes already implemented in all engineering colleges and polytechnics in Gujarat.

Follow-up workshop with colleges for continuing support.

Collaborative process.

Hand-holding of colleges through the process of change.

Capacity Building at Education level -Earthquake Engineering Education in Colleges Development and Implementation of Revised Curriculum in Engineering Colleges Cont’d

Capacity Building at Education level – Gujarat Teacher Training Program –Short Term Courses

•Training Teachers to teach new earthquake engineering syllabus and build a force of earthquake engineering experts in state•Teachers’ Training

•13 courses of one week each for engineering teachers almost equivalent to a full semester program in earthquake engineering – •Courses to be offered twice each for convenience of faculty•Courses go online from July 2003 and to end by March 2004•About 80-120 engineering faculty of Gujarat degree and polytechnic colleges to be covered under this training program

Teachers to be deputed for intensive 19 week program to IIT Kanpur. •Courses to be covered, course content finalised and will be covered under the NPEEE scheme. •Date of commencement- July 2003

Teacher Training Cont’d

Capacity Building at Education level – Gujarat Teacher Training Program –Medium Term Courses

Capacity Building of State of Practice- Training Programs for Practising Engineers of Gujarat

•Engineers’ Training•High demand for courses•Courses preferably on weekends. •Courses free of charge or nominal fees.•Courses on IS earthquake codes- Rationale of codes and design examples and on Seismic Detailing and Design of Concrete and Masonry Structures very popular.

•Two-day workshop on new seismic code IS 1893-2002 conducted in March 2003 -More than 100 participants attended!!•One day workshop on Seismic Detailing Code IS 13920-1993 organised in Ahmedabad on July 6, 2003. 65 participants; 26 from Rajkot, Surat and Baroda

• Additional Courses on Masonry Design and Steel Design in Seismic Regions in next 3 months

• Preparation of 10 courses on seismic engineering covering all aspects of seismic engineering from seismology to foundation problems in earthquakes

• Students, Practising Engineers, Teaching Faculty can obtain copies of these on CDs from GSDMA for self-paced learning

Capacity Building of State of Practice- Training Programs for Practising Engineers of Gujarat

SEISMIC ENGINEERING COURSE MODULES

SEISMIC ENGINEERING COURSE -III

MODULE:

SEISMIC ACCEPTANCE CRITERIA

SEISMIC ENGINEERING COURSE -II

MODULE:

CONCEPTS OF EARTHQUAKE ‘DESIGN” AND RELATIONSHIP TO STRUCTURAL FORM

SEISMIC ENGINEERING COURSE -I

MODULE: INTRODUCTION

SEISMIC ENGINEERING COURSE IV

MODULE:

APPROXIMATE METHODS FOR

CALCULATING NATURAL FREQUENCY

Capacity Building of State of Practice- Training Programs for Government Engineers

•Capacity building of Government engineers greatly enhanced and expedited by having tailored courses for them in seismic engineering from expert faculty•Attendance of courses to be made mandatory.

6 one week courses held by IIT Bombay and IIT Kanpur for Government engineers in Rajkot, Gandhinagar, Bhuj on •Seismic Retrofitting•Seismic Design of Concrete and Masonry Structures•Seismic Design of Bridges and•Special course in Earthquake Engineering for Architects

3 day Masonry Training Course for junior engineers of Jamnagar Municipal Corporation

SEISMIC ENGINEERING TRAINING PROGRAM FOR

DESIGN AND DRAWING PREPARATION

Babtie-ADB Capacity Building TA

GSDMA

May 13-15 2002Alpa Sheth and Allan Mann

IS 4326 - 1993

Earthquake Resistant Design and Construction of Building

Babtie -ADB TA

IS 13920 -1993

DUCTILE DETAILING OF RC STRUCTURES SUBJECTED TO

SEISMIC FORCES

Babtie-ADB TA & GSDMAAlpa Sheth & Allan Mann

Capacity Building of State of Practice- Training Programs for Government Engineers

Road Ahead

4. Formulation of “Systems and Procedures” to assist Municipal and Area Development Authorities when review building plans to check for code conformance of the building designs• Establishing a methodology of drawings submission• Holding a workshop with municipal/ADA engineers to help

them understand what is to be seen in drawings and know “at a glance” if the building is designed for seismic loads or not.

• Holding a workshop for municipal/ADA engineers to apprise them of latest seismic codes and their impact to design of structures

Capacity Building of State of Practice- Training Programs for Municipal Engineers – Road Ahead

Training of Masons

In some urban and most non-urban areas, a large amount of building activity (“non-engineered buildings”) in the hands of the masons with little or no technical input from qualified technical personnel

For Effective Training of Masons, Training Needs Assessment to be carried out – Needs will be different in different parts of the stateTraining Strategy to be formulatedTraining Modules to be preparedInteraction with NGOsCompetency Based Certification

Capacity Building of State of Practice- Masons

There are about 40,000-50,000 masons in the state.

Not more than 2-3% of the present stock of masons is formally trained!!

Capacity Building of State of Practice- Masons - Present Scenario of Masons in State….

Present system of certification of masons requires 10th standard pass and does not have a mechanism for certifying competency of a mason who may have acquired skills through traditional means of apprenticeship

Such masons constitute more than 95 % of the mason task force!!!

Flaw in Present System….Capacity Building of State of Practice- Masons – Flaw in present system….

Competency based certification will provide for Competency check of practicing mason. If there are

any deficiencies, they will be identified and could be rectified by suitable training measures.

Competency check for new entrants to the field

Competency based certification provides an opportunity to a mason for certification in his skill without any age or pre-qualification barriers.

To improve safety standards in the trade.

Capacity Building of State of Practice- Masons – Why competency based certification…

Capacity Building of State of Practice- Masons –Scope of the certification program…

Ideally, all masons should be certified. Need to move step by step. Logistics will not allow for certification of all

masons in the short term It is hoped that atleast 25% (Say 10000-12000)

of the present stock of masons are certified for competency in the next five years- atleast 2000 per year

Certification is proposed to be kept voluntary.

Capacity Building of State of Practice- Masons Creating a Demand for Certification

Considering the importance of certified Mason in all building construction activity, it could be considered to make it mandatory to engage certain % of certified Masons say for the first year 10-20% the second year 20-30% third year 30-50% 4th year onward 50-60%

in public works related to Nagar Palikas, Maha Nagar Palikas, Area Development Authorities and Govt. Civil projects.

Review of IS Earthquake CodesBIS does not review codes often enough.

IS 1893 revised after 18 years. The IS 13920 and IS 4326 not revised after 1993. Today even if you design as per IS 4326, you may be contravening IS 1893!!BIS has stopped preparing explanatory codes and handbooks for the IS codes. Without understanding the rationale behind a clause, it is difficult for engineers to appreciate the import of clauses. No examples to clarify doubts and applications.

Capacity Building - State of Art

A study of review of all Seismic, Wind and Fire IS codes commissioned by GSDMA under WB project.

This study includes preparation of Handbooks and Explanatory codes and recommendations for changes as per the best practices across the world keeping the Indian conditions in mind.

Capacity Building - State of Art

Microzonation Feasibility Study of Seismic Micro-Zonation

Commissioned

Capacity Building - State of Art

Monitoring Mechanisms- Review of Development Control Rules

•Detailed Review of Development Control Rules with specific reference to those DC rules which adversely affect structural integrity such as

•Enclosed Balconies which cause columns to remain untied•Lack of clear agency with supervision responsibility in DC rules•Stilt Floor

Monitoring Mechanisms- New Bill for Licensing of EngineersBackground…

Currently,In Gujarat, one has to register separately for every local authorityRegistration based on degree and experienceNo mechanism to ensure competence before registrationNo punitive provisions Even cancellation of registration with one local body does

not affect registration with other bodies!Not uncommon for structural engineers to use someone else’s license!

Structural Engineer deals with Life safety issues At times a very large number of lives can be

jeopardized Huge projects One-of-a-kind projects

No opportunity for rectification of errors (intentional and unintentional)

Engineering degree and experience does not ensure competence.

Need to have a competence based licensing system

Monitoring Mechanisms- New Bill for Licensing of Engineers Background…

Monitoring Mechanisms- New Bill for Licensing of Engineers

•Workshop held for Competency Based Licensing of Structural Engineers -Overwhelming positive response to the introduction of competency based licensing of engineers•One week E-conference in March-April 2003 on “Licensing Issues in Structural Engineering profession in the Indian context”. More than 550 participants form across the country – Again, a very strong support for examination based licensing of structural design engineers•Draft bill to introduce Act “Professionalisation of Engineers” in final stages•Draft for “Systems and Procedures” for the Act under progress•Bill proposed to be tabled in next Session after approval of the Review Committee

Capacity Building - State of Art “Home owner’s Guide for Earthquake Safety”

Presently, very difficult for a layperson to decide whether his house is safe against earthquakes or whether he should buy into a particular property or how to go about building an earthquake resistant house. New user friendly manual for Homeowners on earthquake safety prepared Fundamentals of earthquakes- the whys and hows How to build a new house and ensure it is designed for

earthquakes How to buy a new flat and ensure it is designed for earthquakes How to retrofit your existing house How to be prepared for an earthquake What to do in the event of an earthquake

Ready for publishing by July end 2003

1. In many areas of the country, technical manpower not available to carry out sophisticated analysis as required by new IS earthquake codes. Need to have an in-between code for small, simple, symmetric one and two storey residential units.

2. New “Small Buildings Code” for Gujarat• Preparation of Complete Code and Handbook with

exhaustive design and detailing guidelines for Seismic Analysis and Design of Small Masonry Houses and Reinforced Concrete Frame Houses (G+1) for various spans and sizes of residential, user owned buildings for zones III, IV and V

• First of its kind in India

Capacity Building - State of Art “Small Buildings Code” - Road Ahead

Thank You…..