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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 What paper do earthquake resistant codes play in Seismic Risk Management?

Risk Hazard Vulnerability

Llanes, C./ PREMIDES, Havana, Cuba Earthquake Resistant Codes 2 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.

Llanes, C./ PREMIDES, Havana, Cuba Earthquake Resistant Codes 3 • 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.

Llanes, C./ PREMIDES, Havana, Cuba Earthquake Resistant Codes 4 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.”

Llanes, C./ PREMIDES, Havana, Cuba Earthquake Resistant Codes 5 • 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.

Llanes, C./ PREMIDES, Havana, Cuba Earthquake Resistant Codes 7 Project of Association of Caribbean States

Llanes, C./ PREMIDES, Havana, Cuba Earthquake Resistant Codes 8 Project of Consensus Conference for the Caribbean, 2002-2004

Llanes, C./ PREMIDES, Havana, Cuba Earthquake Resistant Codes 9 DEVELOPED STUDIES

• Meteorological and Geological Hazards Criteria • Design Standards • Construction Techniques and Detailing • Certification and Testing of Building Materials • Enforcement • Insurance Issues

Llanes, C./ PREMIDES, Havana, Cuba Earthquake Resistant Codes 10 Interreg III.B 2008

Llanes, C./ PREMIDES, Havana, Cuba Earthquake Resistant Codes 11 Earthquakes

Earthquake Resistant Codes 12 Damages in the IX th Region of Araucanía, Chile

Llanes, C./ PREMIDES, Havana, Cuba Earthquake Resistant Codes Author Photos Damages in the IX th Region of Araucanía, Chile

Llanes, C./ PREMIDES, Havana, Cuba Earthquake Resistant Codes Author Photos Damages in Hospitals of the IX th Region of Araucanía, Chile

Who is failing?

Llanes, C./ PREMIDES, Havana, Cuba Earthquake Resistant Codes Author Photos Damages in the VI th Region of O`Higgins, Chile

Prof. Carlos Llanes Earthquake Resistant Codes Author Photos Damages in the VI th Region of O`Higgins, Chile

Llanes, C./ PREMIDES, Havana, Cuba Earthquake Resistant Codes Author Photos Damages in Hospitals of the VI th Region of O`Higgins, Chile

Llanes, C./ PREMIDES/CECAT Havana, Cuba Earthquake Resistant Codes Author Photos 19 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 .

Llanes, C./ PREMIDES, Havana, Cuba Earthquake Resistant Codes 23 Seismic zoning with purpose of engineering.

Llanes, C./ PREMIDES, Havana, Cuba Earthquake Resistant Codes 24 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.

Llanes, C./ PREMIDES, Havana, Cuba Earthquake Resistant Codes 25 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.

Llanes, C./ PREMIDES, Havana, Cuba Earthquake Resistant Codes 26 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:

A: ground maximum horizontal acceleration expressed as a fraction of A I C the gravity corresponding V  W (kN) to a seismic zone. Rd I: coefficient that takes into account the seismic risk as function of the importance of the civil engineering works. Earthquake Resistant Codes 27 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:

Rd: coefficient of reduction by ductility that shall depend on the used structural system and level of ductility in A I C agreement with the zone and V  W (kN) the importance of the civil Rd engineering work. W: weight of the building in C: spectral seismic kilonewton determined coefficient which according to the requirement depends on soil profile of the code. and the period of the

structure. 28 Graph of elastic response spectra.

Llanes, C./ PREMIDES, Havana, Cuba Earthquake Resistant Codes 29 Modal shear force at Modal Analysis the base, Vm.

Cm: modal spectral The fraction of the base seismic coefficient which shear force contributed shall be determined for by the "m" th mode shall each mode using their be determined period of vibration. according to the Tm: according to the following formula: formulas established in

the code, where T= Tm. A I C m W : effective modal Vm  Wm (kN) m Rd weight.

Llanes, C./ PREMIDES, Havana, Cuba Earthquake Resistant Codes 30 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.)

Llanes, C./ PREMIDES, Havana, Cuba Earthquake Resistant Codes 31 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.

Llanes, C./ PREMIDES, Havana, Cuba Earthquake Resistant Codes 32 Importance factors

Llanes, C./ PREMIDES, Havana, Cuba Earthquake Resistant Codes 33 SITE CLASS

• A classification assigned to a site based on the types of soils present and their engineering properties.

Llanes, C./ PREMIDES, Havana, Cuba Earthquake Resistant Codes 34 SITE CLASSIFICATION

Llanes, C./ PREMIDES, Havana, Cuba Earthquake Resistant Codes 35 Site Coefficients

• Site Coefficients and Adjusted Maximum Considered Earthquake (MCE) Spectral Response Acceleration Parameters are introduced:

SDS ≈ Fa Ss

SD1 ≈ Fv S1

Llanes, C./ PREMIDES, Havana, Cuba Earthquake Resistant Codes 36 DESIGN RESPONSE SPECTRUM

Llanes, C./ PREMIDES, Havana, Cuba Earthquake Resistant Codes 37 Hazard maps

Llanes, C./ PREMIDES, Havana, Cuba Earthquake Resistant Codes 38 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) Earthquake Resistant Codes 39 Others enhance coefficients • New Analyses methods are included. – Static analysis • Pushover analysis method – Dynamic analysis • Time history analysis method

Earthquake Resistant Codes 40 Others enhance coefficients

• 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)

Earthquake Resistant Codes 41 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.

Llanes, C./ PREMIDES, Havana, Cuba Earthquake Resistant Codes 42 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.

Llanes, C./ PREMIDES, Havana, Cuba Earthquake Resistant Codes 43 Thanks you very much