January 31, 2018

Simpson Strong-Tie Fellowship Update: Bogotá & Medellín, Colombia

Build Change


Contributed by Dr. James Mwangi, Simpson Strong-Tie Fellow 2017-18

In October, I spent a few weeks at home in California with my family. Build Change’s annual event was also held during my time there, so I was able to meet the entire management team!

While in California, I spent time getting familiar with building designs Build Change uses in Colombia, in preparation for my next assignment. I was able to review the Colombia Building Design Codes (referred to by their official name NSR-10), and the Build Change Evaluation and Retrofit Manual. I was also able to Skype with the team in Colombia to make sure I was up-to-speed on current projects.

On to Bogotá

On October 17, I flew to Bogotá and spent my first week in Colombia with the Build Change staff in Bogotá. From my preparation for the trip, I knew that Bogotá is the capital of Colombia and sits 8,660 feet above sea level with a population of 8.1 million people.  I was impressed by the high-rise brick clad residential buildings in the city, making the city very densely populated.  I was taken aback by the informal brick residential housing dotting along the mountain slopes all around the city, and all I could think was how dangerous they would be in an earthquake.

Poorly built, informal wall in Bogota
Poorly built, informal wall in Bogota

I was surprised how cold (average 60oF) it was being so close to the equator (4.7o N).  One of the first things I noted was the difference in the Colombian Spanish dialect compared to what I was used to in California (mostly from Mexico).  A business day on the streets of Bogotá felt like being on Wall Street, except the pace was a bit slower. Overall, I would recommend the taxis to get around the city. They are very efficient and will take you to-and-from the incredible restaurants around the city easily. Thankfully, the food in Colombia is not half as spicy as that in Indonesia!

Upon arriving, Walter Cano, Build Change’s Project Engineer in Bogotá, immediately grabbed my ear to talk about the Build Change Evaluation and Retrofitting manual. In order to understand the manual and its implications better, we headed out to visit some of the neighborhoods and houses where Build Change is currently retrofitting houses and residential buildings. It gave me a unique insight into the work that the organization has done so far and equipped me with the understanding to support their projects for the upcoming weeks.

I was able to meet with Professor Orlando Arroyo from the Universidad de la Sabana, regarding nonlinear analysis possibilities of existing masonry

Julio Gravito Uni visit
Julio Garavito University visit, L-R: Walter, Anna, Nancy, Sandra, Felipe, James

buildings in hopes of getting a better understanding of possible incremental retrofit schemes of the existing buildings. I hoped that we could reduce the retrofit cost by establishing different performance levels (collapse prevention, life-safety, etc.) for houses that could benefit from retrofitting. Retrofitting involves a unique design and process for each house. In establishing these performance levels, Build Change may be able to work with more homeowners faster.


I also visited Professors Sandra Jerez and Nancy Torres at the Escuela Colombiana de Ingenieria (Colombian Engineering School) “Julio Garavito” regarding their full-scale wall testing project that they will be conducting for Build Change. We discussed the minimum expected test results to update the Build Change evaluation and retrofit manual. Testing will also be carried out on wall panels that Build Changes has harvested from existing buildings. The wall testing will begin in January 2018 and it was agreed that the University team will use this time to familiarize themselves with the Build Change Manual prior to commencing the tests.

Working with the team in Medellín

Medellin Colombia
Medellin, Colombia


Starting the last week of October through November, I was based in Medellín, Colombia. Medellín, the second largest city in Colombia is located at 4900 feet above sea level with a population of 2.5 million.  The beautiful city is very green and surrounded by mountains, making the scenery almost dreamlike.  The weather was comfortable, temperate with an average of 75oF.  The formal housing is similar to Bogotá, as is the informal housing where about sixty percent of the population lives.  What struck me was how clean the city was.  Public transportation was very impressive and included a very efficient and clean metro tram system, metro cable cars that serve the mountainous informal housing communities, bicycles, taxis, and busses.

During my time in Medellín, I accompanied the technical team to the Santa Margarita area of Medellín while they visited possible homes to be used for training building professionals (civil engineers, architects, and project managers) from the Medellín Social Institute for Housing and Habitat (ISVIMED) on how to implement the Build Change Retrofit Manual.

ISVIMED professionals field training Medellin
ISVIMED professionals field training Medellin


I provided an in-depth review of Build Change Evaluation and Retrofit Manual. This included red-marking the manual not only to make it more user-friendly but also reviewing calculations for areas where the manual can be updated to make Build Change’s retrofit techniques more cost-effective. Additionally, I was able to accompany the technical team in the field in Santa Margarita as they trained building professionals from ISVIMED on how to implement the Manual.

I was elated to meet with the doctoral student Alexis Osorio, who is working under Professor Ana Acevedo of Universidad EAFIT, Medellín. EAFIT will be conducting full-scale wall testing for both in-plane and out-of-plane behavior including shake table testing with Build Change. The results from these tests will also be coordinated with the testing from Julio Garavito Engineering School in order to have a better understanding of the wall systems using the different block types in Bogotá and Medellín. The test results will help in the updating of the Build Change manual.

Homeowners receive subsidies from the government to fund home repairs.  Most of the homeowners use this amount to upgrade kitchens and bathrooms, leaving a very small amount for structural components of the buildings.  There is need to update the Build Change manual using the lessons we have learned from the wall testing and retrofit methods used recently. These are addressed in the current manual, but the goal is to make the structural retrofits even more affordable homeowners using the available government subsidies.

James and Adriana on top of Guatape Rock


Guatape Rock
Guatape Rock

Guatapé was one of the highlights of my time in Colombia. Located 81 km (50 miles) east of Medellín, the city has a beautiful array of colorful, historical buildings. After wandering the streets, we scaled the 747 steps of Piedra del Peñol, a giant granite rock extending 200 meters (650 feet) above ground. It was gorgeous!

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