Marcial Blondet

A Challenge to Earthquake Engineering Professionals

Recent earthquakes have caused unacceptably high death tolls. We, the editors of the World Housing Encyclopedia, believe that reducing such an unacceptably high loss of life from earthquakes is the most important challenge facing the global earthquake engineering community. This paper acknowledges the continuing disparity between life loss from earthquakes in developing and developed countries, and the increasing vulnerability in developing countries. A sampling of current efforts to improve construction practices includes the publication of earthquake tips in India, construction manuals in Colombia, and the formation of various international networks to promote collaboration and information sharing. Future possibilities include more rewards for research into inadequately engineered construction, greater emphasis on small-scale, local efforts, and a stronger emphasis on advocacy. We believe that all of us, as earthquake professionals, have a responsibility to make the built environment safer worldwide.

Structural Behaviour and Retrofitting of Adobe Masonry Buildings

Earth is one of the most widely used building materials in the World. Different types of adobe dwellings are made to assure protection and wellbeing of the population according to the diverse zones needs. Therefore, it is important to study the structural behaviour of the adobe masonry constructions, analysing their seismic vulnerability, which may help in preventing social, cultural and economic losses. In the present chapter, an explanation of the seismic behaviour of adobe buildings, a summary of recent research outputs from experimental tests conducted on adobe masonry components and from numerical modelling of full-scale representative adobe constructions are reported. In addition, different rehabilitation and strengthening solutions are presented and results from the testing of retrofitted adobe constructions and components are discussed.

Nonlinear Dynamic Analysis of a Full-Scale Unreinforced Adobe Model

This paper describes the results of a numerical study of a full-scale adobe building model tested on a shaking table. Material properties of adobe masonry were calibrated to represent the wall in-plane seismic behavior, based on a prior numerical analysis of an adobe wall carried out by the authors. The inelastic part of the constitutive model was represented by a softening curve in tension and by a hardening/softening behavior in compression; thus, the fracture energy is a key issue in the modeling process. A finite element model that relies on a homogenous continuum approach was developed in Abaqus/Explicit software. The damage evolution in the numerical simulation represented fairly well the experimental crack pattern, for in-plane and out-of-plane seismic effects. Overall, the calibrated material properties and the explicit solution scheme proved to be appropriate for simulating the seismic behavior and predicting capacity of unreinforced adobe structures subjected to seismic loading.

Seismic Reinforcement for Adobe Houses with Straps from Used Car Tires

After outlining introductory research on a proposed reinforcing system for adobe housing using straps cut from used car tires, the paper reports on full-scale tests. One dynamic and two static tests are described and results presented. The most significant outcome was that a single-room adobe house reinforced by tire straps successfully withstood the strong shaking that routinely collapses unreinforced adobe dwellings. The reinforced house strength, as measured during the shaking, exceeded the requirements of the Peruvian seismic code. This type of reinforced adobe can undergo large horizontal deformations without collapse. Design, construction, economic, and cultural issues are discussed prior to concluding that the proposed system can prevent collapse of adobe houses during damaging earthquakes.

Seismic Behavior and Shaking Direction Influence on Adobe Wall Structures Reinforced with Geogrid

The aim of this work was to assess and validate the construction technology proposed in the manual published by the Pontificia Universidad Católica del Perú (PUCP), Building Hygienic and Earthquake-Resistant Adobe Houses Using Geomesh Reinforcement. In order to validate the proposed technology, two full-scale adobe wall house models were built and subjected to dynamic tests on the PUCPs unidirectional shaking table. Geogrid was used as reinforcement for the adobe walls. One of the models was aligned with the direction of shaking, so that its longitudinal walls were subjected to in-plane forces and its transverse walls to out-of-plane forces. The other model was turned 45° with respect to the direction of shaking in order to have all the walls subjected to both in-plane and out-of-plane forces. The results of both tests were also compared to those obtained during previous tests of an unreinforced adobe model.

The Intervention of Earthen Heritage in Seismic Areas and the Conservation Charters

Earthquakes are recurring natural phenomena that cause cumulative damage to earth constructions that can lead to their collapse. The discovery of earthen architectural heritage in Peru, has led to the re-exposure of adobe buildings, increasing their vulnerability to seismic activity. How can we prevent protect them from further damage their loss and Due to their gradual and progressive destruction, earth constructions located in seismic areas constitute a critical and unique case. The structural response of stone masonry joined with mud mortar depends on the weakest of their construction materials: earth. This paper presents the criteria for structural conservation of earthen architectural heritage and tools for seismic-resistant reinforcement developed by field experts during the last 25 years. The concepts of reinforced earth and liquid mud injection, developed by the Pontifical Catholic University of Peru (PUCP) with support from the Getty Conservation Institute (GCI), are also included in this work. The article also analyzes recent cases of the re-intervention of earth monuments initially restored during the last century and re-destroyed by more recent earthquakes; offers solutions to this situation, ranging from the safest and friendliest to the most aggressive ones. Finally, I concludes expressing the urgent need to reassess the conservation criteria accepted by the International Charters ratified by ICOMOS and UNESCO regarding earthen architectural heritage located in seismic areas.

Evaluation of a Rope Mesh Reinforcement System for Adobe Dwellings in Seismic Areas

Throughout the world millions of people are at unacceptable risk because they live in unreinforced earthen dwellings, which have consistently shown extremely poor structural behavior during earthquakes. This article presents a design procedure for the structural reinforcement system for one-story earthen constructions located in seismic areas. The proposed reinforcement consists of a mesh made of nylon ropes which envelopes completely all the earthen walls and maintains structural integrity even after the walls have been significantly damaged. It is thought that its use has the potential to protect the lives of millions of families which are currently are at risk, and the integrity of invaluable earthen historical monuments.

Sustainable dissemination of earthquake resistant construction in the Peruvian Andes

Abstract This article describes the challenges and initial accomplishments of a project developed by the Pontifical Catholic University of Peru (PUCP) to disseminate technology and to train low-income families in the Andes Mountain region to build earthquake-resistant homes made of adobe bricks. The initiative has focused on improving the livability of households through affordable seismic reinforcement of traditional construction processes to enhance the social sustainability of housing in the area. We selected the rural Andean community of Pullo as a case study because of its preponderance of non-reinforced adobe construction and poverty. The research team developed tools and methodologies for technology transfer, worked with local residents to raise awareness of the high seismic vulnerability of adobe dwellings, and introduced the concept of seismic reinforcement. This article explores the barriers to disseminating earthquake-resistant technology in the study area and presents adaptive measures to overcome these challenges. Initial results demonstrate the positive impact of educational workshops to raise seismic awareness and to introduce earthquake-resistant construction among rural dwellers. The project is deemed to have wider applicability to other communities in seismic areas with similar housing, social, and economic conditions.