Status of Earthquake Resistant Building Codes in Cuba …uwiseismic.com/Downloads/CARLOS_BURON.pdf · Status of Earthquake Resistant Building Codes in Cuba and ... Cuba Earthquake

Status of Earthquake Resistant

Building Codes in Cuba and

other Spanish speaking

countries in the Caribbean.

By Prof. Dr. Eng. Carlos Llanes Burón

PREMIDES/CECAT/ Faculty of Civil Engineering/ CUJAE

Havana, Cuba

THREE-DAY WORKSHOP TO LAUNCH THE GLOBAL

EARTHQUAKE MODEL IN THE CARIBBEAN.

PORT OF SPAIN, TRINIDAD AND TOBAGO

Llanes, C./ PREMIDES,

Havana, Cuba Earthquake Resistant Codes 2

What paper do earthquake resistant codes

play in Seismic Risk Management?

Risk Hazard Vulnerability



Vulnerability factors

• Inside the technical factor the existence of

the building codes are framed, which allow

to design and analyze the structures

considering criterions of Risk

Management, which permit to prevent and

mitigate natural disasters.



• Many countries and regions develop

seismic and wind load codes that they

provide economic and reliable designs of

buildings and structures in their respective

areas. The intense international exchange

in this field of science has given place to

most of these Codes respond a same

basic outline, which corresponding to the

guidelines established in International

Standards.



International Standard ISO 3010

• In the case of seismic codes, the first and

second editions of ISO 3010. Bases for

design of structures – Seismic actions on

structures, was elaborated in WG1 under

TC 98.

• The standards prepared by TC 98 serve as

references in the field of buildings and

construction and they are frequently called

as “Code for Code Writers.”

• The stochastic character of

geological phenomenon makes

necessary the use of design

codes, because the prediction of

the seismic loads, during the

service life of a structure is not

precise. The probability

prediction of the prospective

seismic acceleration in a place

could provide an economically

reliable design building.



RECENT WORKS

The International Project of 2002- 2003

"Upgrade the Codes of Construction of the Great

Caribbean for Winds and Earthquakes"

directed by the Association of Caribbean States

had the following objectives:

• Reviewing the corresponding standards for

countries of the Greater Caribbean.

• Elaborating the Model Codes for Wind and

Earthquake.



Project of

Association of Caribbean States



Project of Consensus Conference

for the Caribbean, 2002-2004



DEVELOPED STUDIES

• Meteorological and Geological Hazards

Criteria

• Design Standards

• Construction Techniques and Detailing

• Certification and Testing of Building

Materials

• Enforcement

• Insurance Issues



Interreg III.B

2008

Earthquake Resistant Codes 12

Earthquakes


Havana, Cuba Earthquake Resistant Codes

Damages in the IX th Region of

Araucanía, Chile

Author Photos



Damages in the IX th Region of

Araucanía, Chile

Author Photos



Damages in Hospitals of the IX th

Region of Araucanía, Chile

Author Photos

Damages in Hospitals of the IX th

Region of Araucanía, Chile


Havana, Cuba Earthquake Resistant CodesAuthor Photos

Who is failing?

Prof. Carlos Llanes Earthquake Resistant Codes

Damages in the VI th Region of

O`Higgins, Chile

Author Photos



Damages in the VI th Region of

O`Higgins, Chile

Author Photos

Llanes, C./

PREMIDES/CECAT


Damages in Hospitals of the VI th

Region of O`Higgins, Chile

Author Photos

Earthquake, March 20th, 2010

Earthquake, March 20th, 2010 Santiago

of Cuba and Guantanamo

Photos from Internet

Earthquake, April 12th, 2010



SYNTHESIS OF CURRENT CUBAN

STANDARD FOR SEISMIC LOADS.

• In this code, the NC 46: 1999, the basic requirements for the design and construction of earthquake resistant constructions located in seismic hazard zones, are established. It includes as buildings as to civil works with the purpose to reduce or mitigate their degree of vulnerability, except special structures as nuclear, electric, mechanical and similar plants; for such cases, specific considerations which shall be used according to requirements established in this standard are required .



Seismic zoning with purpose

of engineering.



The design motions, as function of the

maximum acceleration of horizontal

component obtained for rock to evaluated

seismic hazard, are defined. The values of

Peak Ground Acceleration (PGA), with

10% probability of exceedance in 50 years

of service life corresponding to a return

period of 475 years, were obtained.



Evaluation of seismic actions by

equivalent static analysis.

• The equivalent static analysis could be

adopted for those buildings classified like

regular according to the code whenever

their height is inferior to 80 m and their

fundamental period is not higher than 2

seconds.


The horizontal component or total base shear,

V, due to the seismic action that it act on a

building, will be determined by the formula:

(kN) W C

VRd

IA

A: ground maximum

horizontal acceleration

expressed as a fraction of

the gravity corresponding

to a seismic zone.

I: coefficient that takes into

account the seismic risk as

function of the importance

of the civil engineering

works.

28

The horizontal component or total base shear,

V, due to the seismic action that it act on a

building, will be determined by the formula:

(kN) IA

V WC

Rd

Rd: coefficient of reduction by

ductility that shall depend on

the used structural system

and level of ductility in

agreement with the zone and

the importance of the civil

engineering work.

W: weight of the building in

kilonewton determined

according to the requirement

of the code.

C: spectral seismic

coefficient which

depends on soil profile

and the period of the

structure.



Graph of

elastic

response

spectra.



Modal AnalysisModal shear force at

the base, Vm.

The fraction of the base

shear force contributed

by the "m" th mode shall

be determined

according to the

following formula:

Cm: modal spectral

seismic coefficient which

shall be determined for

each mode using their

period of vibration.

Tm: according to the

formulas established in

the code, where T= Tm.

Wm: effective modal

weight.(kN) m

d

mm W

CIAV

R



Current situation in Cuba and other Spanish

speaking countries in the Caribbean

• ISO 3010: 2001 Bases for design of structures –Seismic actions on structures.

• FEMA 356 Prestandard and commentary for the Seismic rehabilitation of buildings, 2000.

• ASCE/SEI 07: 05 and ASCE/SEI 07: 10.

• International Building Code (IBC) 2009.

• NSR 10. Colombian Code.

• NSE 10. Guatemalan Code.

• RD. Dominican Code. 2008.

• NC 46: 2011. Cuban Code. (It is being reviewed.)



OCCUPANCY CATEGORY OF

BUILDINGS AND OTHER STRUCTURES

• The occupancy categories range from I to

IV, where Occupancy Category I

represents buildings and other structures

with a low hazard to human life in the

event of failure and Occupancy Category

IV represents essential facilities.



Importance factors



SITE CLASS

• A classification

assigned to a

site based on

the types of

soils present

and their

engineering

properties.



SITE CLASSIFICATION



Site Coefficients

• Site Coefficients and Adjusted Maximum

Considered Earthquake (MCE) Spectral

Response Acceleration Parameters are

introduced:

SDS ≈ Fa Ss

SD1 ≈ Fv S1



DESIGN RESPONSE SPECTRUM

Hazard maps




Others enhance coefficients

• Response modification coefficient

– Irregular and Regular Classification in plan and

elevation.

• Seismic load effects

– redundancy factor

– overstrength factor

• Combined Response Parameters

– Square Root of the Sum of the Squares method

(SRSS)

– Complete Quadratic Combination method

(CQC)



• New Analyses methods are included.

– Static analysis

• Pushover analysis method

– Dynamic analysis

• Time history analysis method



• Seismic special hazard intensities

– Next to an active fault line

• Adjust to seismic special hazard intensities

SDS ≈ Fa Ss Na ≤ 2 and ≥ 10 km

Max (1.25) to Min (1.0)

SD1 ≈ Fv S1 Nv ≤ 2 and ≥ 15 km

Max (1.40) to Min (1.0)



CONCLUSIONS

• When it is likely, in a determined place,

that a seismic hazard takes place, the

structures and civil works will be more

vulnerable, providing that they do not

fulfill the requirements established by the

corresponding earthquake resistant

codes.



CONCLUSIONS

• An architectural design that combines

the aesthetics and an appropriate

structuring and configuration to lateral

loads induced by natural phenomena

will be more competent and in better

conditions to mitigate the likely risk that

a disaster takes place.

Thanks you very much

Documents

Status of Earthquake Resistant Building Codes in Cuba …uwiseismic.com/Downloads/CARLOS_BURON.pdf · Status of Earthquake Resistant Building Codes in Cuba and ... Cuba Earthquake