Earthquake Research
Research at Detroit Mercy focuses on design for seismic (earthquake) loadings for structures located around the world. Many people around the world don’t have adequate material resources or knowledge about how to design safe buildings.
One consequence is that a very high number of people are killed in developing countries. In 2010, Haiti had a 7.0 Earthquake that killed more than 100,000 people according to the USGS. Detroit Mercy responded to this immediate need by sending a team of professionals to Haiti to assess damage to schools. (Read how Detroit Mercy assists in Haiti school inspections)
Detroit Mercy research focuses on developing materials and methods that will prevent tragedies like this. People in developing countries often can’t afford to construct building that will withstand seismic loads. Then once the buildings have been made, there is little that can be done to make them more durable. We are working on solutions to this. (Read about new methods and materials)
Are earthquakes an issue for Detroit? The public has not had much concern for earthquakes in Detroit, but professional engineers have considered their potential impact. Building codes for Michigan require attention to the possibility of earthquakes. These are based on historical records for the last couple hundred years which say there is a potential for some seismic motion. This is most likely caused by feeling effects from earthquakes in other parts of the country. Even with that, many brick and concrete block buildings in Detroit would likely damaged by small earthquakes. Additionally, the earth is always changing. It is possible that we could have a return to pre-historic times when large earthquakes were more common in Michigan. Therefore, it is good to be prepared.
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Detroit Mercy assists in Haiti school inspections
In conjunction with the Jesuit Refugee Service (JRS), Detroit Mercy organized two volunteer teams of engineers and architects to assist Haiti’s Ministry of Education in assessing damaged school buildings in Port au Prince during the month of March. Architecture professor Gilbert Sunghera, S.J. and alumnus Joe Coriaty ’78, a partner in the architecture firm of Frederick Fisher and Partners in Los Angeles, comprised the first team, who served as building inspectors from March 8-13. The second team of Architecture alumna Marie Haener-Patti ’80,’85, and professional engineer Nathan Galer from Seattle, served as building inspectors during the week of March 16.
In total, the Detroit Mercy teams evaluated the condition of 55 school buildings. According to Fr. Sunghera, approximately 60 percent of those schools were partially usable (though not by American standards), and about 15 percent were beyond repair. Team members completed a five-hour, online training program conducted by Architectural Engineering Professor Alan Hoback, in preparation for their assignment.
“It was wonderful to use our professional training and tap into the Jesuit network to help, “ says Fr. Sunghera. “All team members would go back in a heart beat.” Although the initial project is completed, Fr. Sunghera will work through the Jesuit networks to determine any future assistance.
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New Methods and Materials
Use of new materials in developing Countries
A major problem in developing countries is poor construction. Concrete is primary building material since it is made from common materials from the ground. However, developing countries rarely use timber or steel. Steel is often too expensive since it is made in developed countries and shipped where needed. Also, wood is usually not available because of few forests and it is expensive to ship. Therefore, the primary building materials are concrete or clay. Concrete is used in masonry blocks or in cast beams and columns. Clay is made into bricks.
The problem with concrete and brick is that they are not effective at resisting forces in earthquakes that cause tension and shear. These forces cause cracking and failure. Since concrete is heavy, that makes seismic loads worse when earthquakes shake heavy buildings. Therefore, a building that may stand up day to day could fall in earthquakes.
Two problems need to be solved: First, what should be done with buildings already built using poor construction? Second, how can new construction be made that will resist earthquakes but not cost too much money?
Retrofit of existing buildings
What can be done to make building durable? The same problem can exist with older buildings in the US. In developed countries, one solution is to glue on carbon fibers that are also used in lightweight airplane wings. This is much too expensive to consider doing in developing countries. If they could not afford the steel bars in the construction originally, they can’t afford high-grade airplane parts.
Mohammad Mansourikia and Dr. Hoback have worked on using less expensive materials. For example, geotextile is a fabric that is used in other civil engineering applications. The fabric can be glued onto the sides of buildings in X patterns to add strength. It is much cheaper than carbon fibers.
Read more: Retrofit of Unreinforced Masonry Walls Using Geotextile and CFRP, M.T. Mansourikia & A. Hoback, Electronic Journal of Structural Engineering, Issue 8 of Volume 14, 2014.
Constructing new buildings
Steel bars in concrete buildings are the most common method to carry shear and tension forces caused by earthquakes. Dr. Hoback and a few students are looking at inexpensive building materials that can be used instead of steel bars.
One possible material is bamboo. Bamboo is a grass that grows across the world. It is stronger than most wood. It has high tension strength, but not as high as steel. Since it grows very quickly, it doesn’t take much forest space to grow it.
There are a few problems with bamboo that need to be resolved. First, when put into concrete, it absorbs the water and swells, then later it dries it contracts. This makes it hard to connect with concrete which doesn’t swell. Our sister university, Santa Clara U is working on this problem.
Second, most engineers have no experience with bamboo. Therefore, Detroit Mercy is working on evaluating different uses of bamboo in parts of concrete structures. Also, Detroit Mercy is working on new ways of connecting the bamboo to the concrete.