QUESTION. Does the collapse of several buildings during the earthquake in Venezuela show that seismic regulations were not followed?
ANSWER. There are several factors. Seismic regulations exist in Venezuela, it is the COVENIN 1756 standard, which has seismic zoning and microzonation, and was reinforced after the 1967 earthquake. The last update is from 2019. The problem in Caracas and La Guaira is the soil composition. They are sediment areas, not rigid or solid soil. They are deposits formed over the years by alluvium on which construction was directly built. In La Guaira, these areas were not suitable for the type of constructions that were made. Even after the 1999 landslide, very tall constructions with soft ground floors were built. That is, when the bottom part of the building is open, only the columns are visible, without masonry walls, causing the building to move much more. Without resistance, all the weight falls on them during an earthquake, becoming a vulnerable point in the structure. This generates the pancake effect, where the building collapses like an accordion.
Q. Was there a lack of supervision in the complexes built after the La Guaira landslide?
A. Yes, absolutely. There was a very large lack of supervision by the Government. The pancake effect occurs because the columns on the ground floor are not well calculated or fail in the connection with the slab. Sometimes construction companies also try to cut costs by using less steel or spacing the stirrups of the columns. In Venezuela, almost all construction is concrete with beams and columns. Concrete resists compression, but steel provides ductility for the building to move without breaking. If the steel is not well calculated or the stirrups are too far apart to save money, the structure collapses. The real problem is not the lack of regulations, but the lack of Government oversight for their correct implementation.
In La Guaira, many new constructions of the Misión Vivienda were built on sediments from the 1999 landslide and were too tall. Venezuela has excellent regulations, but they remain on paper because no one verifies that what is built matches the plans. From my point of view, one of the factors that has significantly influenced this whole catastrophe is the lack of enforcement to ensure compliance with existing regulations. There is no one overseeing that those buildings that collapsed in La Guaira were built in accordance with the regulations that corresponded to that land and geological zone. There is a need for thorough and technical control, similar to what is done in other countries, where municipal inspectors verify the works. In Venezuela, unfortunately, it was historically known in the industry that many construction companies paid off the inspector and the inspection never took place.
Q. What do you think caused the collapse of several buildings in Caracas?
A. I have come to the conclusion that it is a matter of multiple factors. First, geology: in places like Los Palos Grandes, there are up to 380 meters of sediment before reaching solid rock. Soil studies must be conducted to determine the allowed height and foundation typology, such as the use of piles. Second, these were shallow earthquakes, at 20 and 10 km, so the waves were not absorbed by solid rock and shook the soft ground like jelly.
Q. There are videos of Venezuelan rescuers showing the use of white cardboard in constructions. Shouldn't that material be used in construction?
A. That is a common misconception. The slabs, that is, the building floors, are constructed with expanded polystyrene to lighten the structure, make it more efficient, and resistant. The anime, as it is called in Venezuela, is only a filler, what matters is the structural part of concrete and steel.
Q. What should be done for the future reconstruction of the affected areas?
A. There must be a genuine analysis of which areas are buildable and at what heights. The seismic microzoning must be respected, evaluating which standing buildings can be reinforced and which cannot. In La Guaira, the mistake was building on the landslide sediments. It is not a matter of profitability, but of saving lives. Buildings must be designed to give people time to evacuate.
Q. What does Venezuela need for this reconstruction?
A. Venezuela needs Venezuelan architects, who know the materials, construction methods, and the idiosyncrasy, but there are also new technologies developed outside the country that must be absorbed, and especially there is a need for thorough control of everything that will be rebuilt, how it will be done, and in what way, because reconstruction must be done to prevent this from happening again.