I have been encountering quite a few engaging perspectives since the circulation of my post on 'The OECS Buildings Codes vs Hurricane Irma". Recently, I was tagged in a post from a Chevening alumna from The Bahamas, querying my feedback on a blog entry by a Bahamian author. The title of the entry was "Irma: A Meditation on Hurricanes and the Bahamas". In reading the post, it was quite an interesting opinionated piece, and I decided to post my feedback within my own blog. My perspective is, as follows:
Well, I've never been to The Bahamas so I won't be able to definitively endorse or refute what's suggested within the post.
It's an interesting take on hurricane resistivity. The author did capture the barometric pressure contributing to how destructive a hurricane can be, but an additional element to be considered is the speed that the hurricane is moving. Sluggish movement means that the storm has a longer time on the ground. Longer time on the ground means that each building is taking a beating from the force of the winds over a longer period of time. Durability and endurance then become key factors in a building's resistivity.
Some valid points are within the post. I'm curious about the "reinforced poured concrete". If it's what I'm thinking it is, it sounds like a beneficial construction method to consider. However, I'm actually more curious about the reinforcement used (sizes and intervals - since that's what increases the integrity of the structure). However, many of the structures constructed of reinforced concrete block walls in the islands that were hit by Irma seem to still be standing, so I'm not sure if the block wall construction is under major scrutiny at the moment. That being said, I'm most curious about the roof construction, since that's the most vulnerable element in a building when enduring storm-force winds. If there are any new technologies introduced to secure roofs better (that won't excessively hurt the average person's pocket) then I'm sure they'd be welcomed in the wider region. The wall construction would really play a bigger part when it's impacted by the new roof construction techniques (whether the walls, beams, or columns would need additional reinforcement, etc).
On one hand I understand the perspective about The Bahamas not being mountainous and therefore tends to avoid land slippage caused by heavy rains in a storm, but the author did mention that the hilly topography of an island tends to reduce the intensity of the storm when it passes over. The other thing to note is that quite often hills offer protection to structures in lower lying areas from hurricane winds (flatter areas tend to be more exposed). However, alternatively, there's also the concept of the hills sometimes creating wind tunnels if they're a bit close together - but I digress.
Some of the design elements mentioned are a bit typical of the older structures in the region that were built during colonial times. The raised foundations in flood prone areas are a common feature in a lot of the islands. For example, the entire historic district in Roseau, Dominica has buildings that are raised a few feet off the ground. The transom window (above doors for cross-ventilation) is also typical in many of the antiquated structures from that era. It's also used to allow hot air to rise and escape at that level.
The author made a statement towards the end of this post that has spurned my curiosity a bit: "that we should study and standardize our building techniques—all of them, from the working in wood to our facility with concrete". Do you by chance know if The Bahamas has an approved Building Code? I'd be interested in taking a peep at it if you do. That would be a starting point in supporting the author's perspective.
Nicolette Bethel's Blog Entry, can be found here:
https://nicobethelblogworld.wordpress.com/2017/09/09/irma-a-meditation-on-hurricanes-and-the-bahamas/
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