Having quizzed Laytoe’s structural engineers, I know that what they don’t do is assemble or repair the bits that keep a building upright. No nuts, no bolts, no lefty-loosey or righty-tighty. They don’t appear to engineer or even fix anything. Structural engineering isn’t what I thought it was.
WHAT IS IT THEN?
Structural engineering is branch of civil engineering; it deals with buildings and other upright structures. Please don’t ask what civil engineering is. Structural engineers know what keeps buildings up and what stop buildings falling down. They know how much weight and pressure each part of a building can take. However, they don’t manually install the bricks, beams or joists that provide the required support. They look at foundations, poke about a bit, take measurements, peer at cracks, ask questions and then input this and other data into a computer. All of this allows them to produce reports and calculations.
Structural engineers also use terminology which, when broken down, isn’t rocket science, but still isn’t what you might think it should be. The team at Laytoe use phrases like structural integrity and load paths which I used to pretend to understand. But no longer. Here goes…
STRUCTURAL INTEGRITY MEANS?
The structural bit is easy. All buildings are structural; they all have solid parts that keep them up. Integrity is where you might furrow your brow. With people, integrity implies respect, honesty or strong morals. If applied to buildings, are we saying that the structure of St Paul’s Cathedral has more integrity than the Playboy Mansion? Actually, it might do as structural integrity relates to the quality of the structure. Structural integrity means that the components of the building stay strong and keep their shape under the stress and pressure they are subjected to over the years.
In the case of St Paul’s, this means that after a rebuild in 1710 following the Great Fire of London and partial damage to the roof during the Blitz, the design and construction standards of this iconic demonstrated enduring structural integrity. As for the stresses that 10236 Charing Cross Road in Los Angeles is exposed to, one dreads to think.
Structural engineers assess the structural integrity of a building by inspecting and monitoring areas of concern. Cracks around your widows or door frames, for example, could indicate issues that, if unchecked, will lead to significant structural damage. This then impacts on the structural integrity of your property.
Load: yes, weight and pressure: got that. A path is a path. So before I confirm with Laytoe’s experts, I will tentatively suggest that a load path is a horizontal surface somewhere in your house that can take heavy loads. To me, that sounds like floors. A window sill might be a load path, a new coffee table is definitely not. Let’s see how wrong I am.
Depending on how you define incorrect, I was almost half right. The load in a load path is definitely a load in the conventional sense. But a path is not a flat horizontal surface that you might walk on. The path of a load path refers to the direction in which loads are transferred. As such, a wall is an example of a load path, even though it is an upright vertical structure, because the direction of the load from the roof of a house is through the walls. Load paths start at the top of a building and travel down to the foundations. Travelling down doesn’t mean that the direction is vertical; the weight, pressure and movement of heavy furniture and people does indeed travel horizontally across the floor (and ceiling above) before transferring vertically down the walls.
TRUST THE EXPERTS
There’s only so much googling, going off on tangents and interrogating of colleagues that one can do before one realises that it takes years of study and practice to be able to plan and design the structures that many of us take for granted. From majestic cathedrals to humble lean-tos, I for one have a newfound respect for the people who know how to keep our walls, roofs and floors safe and stable.