January's devastating earthquake in Haiti has been viewed from every possible vantage point, spanning humanitarian to political perspectives. But, Cornell University Professor of Structural Engineering Ken Hover Û a late addition to the World of Concrete speaker roster Û reflected on how Haiti, much like countries accounting for the bulk of world population, depends on concrete and masonry construction.
Showing dozens of photos of his recent Port-au-Prince trip, Hover described inspection of the Cornell-sponsored Gheskio medical clinic campus buildings. He explained that concrete and masonry typically are the building materials of choice in nations like Haiti because there simply is no wood, clay, fiberglass, or other raw material available without being imported. After examining the medical center and labeling certain structures as uninhabitable, he went on to inspect other buildings for possible habitation. He found that since the shockwave traveled north-south, most walls running parallel to it remained intact, while walls aligned east-west failed.
The professor detailed conventional home and light-duty/light-commercial construction in Haiti, which involves support beam at the corners and masonry block used as walls. Typical home erection involves incremental building as money becomes available and small amounts of cement and block can be purchased. Often blocks are homemade from a single mold, and the maker typically will attempt to get 20 units from one bag of cement, resulting in variable strength grades.
While emphasizing and documenting the critical need for quality design, materials and construction technique, Hover also saw several excellent examples of well-made commercial buildings that performed as they should. And while many of the more modern buildings stayed standing so people could be evacuated, structural damage would eventually require them to be torn down.