This study examines the mechanical properties of adobe and their relationship to vulnerability in adobe buildings. Experimental testing was conducted to determine geometric characteristics, flexural strength, and compressive strength of individual adobe blocks and walls. Various structural characteristics of adobe buildings like wall density, dimensions, and construction quality were analyzed. A vulnerability index is proposed based on these characteristics to classify adobe structures according to their expected damage from seismic events. The study concludes that a lack of regulation and quality control in adobe construction contributes significantly to vulnerability, and that structural interventions and strict construction standards can reduce the vulnerability of adobe buildings.

1. MECHANICAL CHARACTERIZATION OF THE ADOBE AND THEIR RELATION WITH VULNERABILITY cDr. Raúl González Herrera, M.A. Borraz María Alejandra Santiago, M.C. Jorge Aguilar Carboney, M.C. Carlos Narcía Lopez, and Dr. Janio Alejandro Ruiz Sibaja

2. INTRODUCTION In Tuxtla Gutierrez, there are significant number of adobe buildings, these have different vulnerability levels, in this investigation has the proposal to find a correlation between the pieces strength, the effect of the regularity of the architectural project, and the density of walls, like an attempt to present a proposal for vulnerability indices for adobe structures.

3. INTRODUCTION

4. INTRODUCTION

5. EXPERIMENTAL WORK Adobe characterization was performed by Ovando and Ruiz (2008) considering the following stages: Geometric characterization: length, width and thickness as well as obtaining the weight of each piece . Pieces Flexural strength . Pieces and Walls Compressive strength Mortar Compressive strength .

6. EXPERIMENTAL WORK Adobes have a length about twice of the width (50/30 = 1.67). Relationship between length and height was 4-1 (50/10 = 5-1) Height greater than 8 cm (10cm).

7. EXPERIMENTAL WORK

8. EXPERIMENTAL WORK Adobe block weight Standard dimensions (cm) 50,00 30,00 10,00 24,00 Average (cm) 48,65 28,54 9,19 23,30 Standard deviation 0,46 0,40 0,35 1,00 Coefficient of variation 0,01 0,01 0,04 0,04

9. EXPERIMENTAL WORK Adobe flexural resistance (Kg/cm 2 )

10. EXPERIMENTAL WORK Wall of adobe compressive resistance (Kg/cm 2 ) Block of adobe compressive resistance (Kg/cm 2 )

11. HISTORICAL BACKGROUND Damage to adobe structures in the earthquake of October 21th, 1995 in Villaflores, Chiapas.

12. VULNERABILITY Classification of building types in vulnerability classes according to the MSK-92 scale

13. VULNERABILITY Percentage distribution of house that were considered vulnerable according to INEGI information in the censuses of 1990 and 2000 (Sánchez, 2005).

14. VULNERABILITY These houses are of adobe, Do they have the same vulnerability?

15. VULNERABILITY Plants typical of adobe buildings with different aspect ratios (1:5, 1:4 and 1:1.5), (Gonzalez and Gomez, 2007)

16. VULNERABILITY Wall density in terms of length of the construction of adobe, based in Rodriguez (2004). Adobe constructions Number of levels

17. VULNERABILITY Vulnerability adobe buildings of varying construction and structural characteristics Indicator Vulnerability A B Adobe Compression resistance <20.00 kg / cm 2 > 20.00 kg / cm 2 Mortar compression resistance <35.00 kg / cm 2 > 35.00 kg / cm 2 Adobe dimensions thickness <30cm Minimum section 30x30x8 Wall density < 8.00% > 8.00% Length / width ratio > 1.1.5 <1:1.5 Height > 3.50m <3.50m single level Confining elements of concrete in corners, changes of direction, chains, similar to confined masonry If the features are not adequate or sufficient Includes Adobe recover against humidity Not included or no maintenance Includes plaster according to the specified and its maintenance Ceiling Light or heavy with a detailed design or inadequate Light, well anchored, with straps to ensure the stability of the diaphragm

18. CONCLUSIONS The most of the problem and deaths that have the adobe buildings originate has an explanation: there is almost enough research and experimentation, but NOT REGULATION . The adobe brick is a traditional material, which is and can still be used, but it must be prepared keeping a strict quality control . There are adobe buildings, which for technical quality, quality control during the building process, architectural or structural interventions, are less vulnerable than others. This article proposes a set of criteria that need to be consider if we want to have lees adobe vulnerability .

19. Thanks for your attention cDr. Raúl González Herrera, M.A. Borraz María Alejandra Santiago, M.C. Jorge Aguilar Carboney, M.C. Carlos Narcía Lopez, and Dr. Janio Alejandro Ruiz Sibaja