1 Introduction
Date | Magnitude (Richter scale) | Epicenter |
---|---|---|
October 6, 1911 | 7.0 | Central Mountains |
October 11, 1918 | 7.5 | Mona Passage |
August 4, 1946 | 8.1 | Scotia Bay, Samana |
January 8, 1962 | 6.5 | Central Mountains |
March 23, 1979 | 6.1 | Higüey |
June 24, 1984 | 6.7 | La Romana |
September 22, 2003 | 6.5 | Puerto Plata |
January 12, 2010 | 7.0 | Puerto Príncipe, Haiti |
2 Previous studies
3 Objectives and scope of the ONESVIE project
4 Code practice in the Dominican Republic
4.1 1979 provisional recommendations for the seismic analysis of structure
4.2 Regulations for the seismic analysis and design of structures R-001
Period (s) | Sa (%g) M-001 | Sa (%g) R-001 | Difference | Difference (%) |
---|---|---|---|---|
0 | 0.127 | 0.149 | 0.02 | 18 |
0.01 | 0.127 | 0.168 | 0.04 | 32 |
0.02 | 0.127 | 0.186 | 0.06 | 46 |
0.03 | 0.127 | 0.204 | 0.08 | 61 |
4.3 Seismic hazard maps for Haiti
4.4 Seismic and windstorm evaluation of existing RC buildings for the Dominican Republic
5 Methodology
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Schools selection;
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Architectural survey;
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Structural survey;
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Structural modeling;
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Recommendations.
5.1 Schools selection
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The structure’s material must be reinforced concrete;
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Have two or more storeys;
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Have a medium to high vulnerability index [from the ONESVIE study (ONESVIE 2014)];
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The year of construction must be before 2011. (It is assumed that the structures built with the current code are not vulnerable.)
5.2 Architectural survey
5.3 Structural survey
5.4 Preliminary structural model
5.5 Refined structural model
5.6 Recommendations
6 Case study: the Fernando Cabral Ortega School
6.1 Architectural and structural survey
Sample ID | Building | Element type | Diameter (cm) | Area (cm2) | L/D | Factor | Load test (kg) | Stress test (kg/cm2) | Stress test (MPa) |
---|---|---|---|---|---|---|---|---|---|
N#l | 1 | Beam | 5.6 | 24.63 | 1.75 | 0.98 | 9384 | 381 | 37 |
N#2 | 2 | Beam | 5.6 | 24.63 | 1.75 | 0.98 | 10,369 | 421 | 41 |
Mean | 401 | 39 | |||||||
Stdv | 20 | ||||||||
COV | 5% |
Sample ID | Building | Element type | Diameter (cm) | Area (cm2) | L/D | Factor | Load test (kg) | Stress test (kg/cm2) | Stress test (MPa) |
---|---|---|---|---|---|---|---|---|---|
N#l | 1 | Column | 5.6 | 24.63 | 1.75 | 0.98 | 5148 | 209 | 20 |
N#2 | 2 | Column | 5.6 | 24.63 | 1.75 | 098 | 3374 | 137 | 13 |
N#3 | 3 | Column | 5.6 | 24.63 | 1.75 | 0.98 | 4877 | 198 | 19 |
Mean | 181 | 18 | |||||||
Stdv | 39 | ||||||||
COV | 21% |
6.2 Structural model
6.3 Results
6.3.1 Pushover analysis
7 Conclusions
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The seismic demand expected with the seismic regulation of 1979 could be underestimated between 32 and 61% in school structures from 1 to 3 levels, located in the province of San Cristóbal, when compared with the seismic demand obtained with the current seismic code.
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Although according to their authors, the seismic hazard maps developed by the USGS cannot be considered complete for the eastern part of Hispaniola, they show that spectral accelerations for a 2% and a 10% probability in 50 years suggested by the current regulation could be underestimating the seismic demand for the entire area of the country located below the northern fault. This implies that more research is needed.
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It is necessary to develop or implement a code for the evaluation of existing structures in the Dominican Republic, since the current one was not intended for this purpose.
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The structural configuration of typical schools in the Dominican Republic promotes a poor seismic behavior (short column effect, buildings with irregular plan shapes, etc.) as observed during the Puerto Plata’s earthquake in 2003.
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For the case of the Fernando Cabral Ortega School, concrete compressive strength obtained by destructive test resulted in a high coefficient of variation in both beam and column elements. This implies that more tests must be performed to obtain a representative resistance for the structural elements. However, it is important to mention that the other assessed schools had concrete strength well below those allowed by the design codes, which suggests that the quality control during the construction process was very deficient.
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The evaluation of the performance of the structure with the demand estimated according to the current seismic code showed that the expected level of damage exceeds the limit state for a structure with special occupation and, therefore, must be reinforced. The same observations apply for the remaining 21 schools evaluated in this project.
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When evaluating the proposed scheme reinforcement, the analysis results showed that the level of expected damage is within the limits for a special occupation structure, and therefore, it is demonstrated that this solution is adequate.