12 Structural Foundation Tips, a Horror Story and a Good Method

Choose the right Expert

Groundworks and foundations are potential financial black holes. They are often misunderstood and mistakes are seldom cheap or delay free. It is as much about knowing what not to do as how best to obtain the support you must have to carry off a successful project. There are a surprising number of so called experts who are ill equipped to lead technical projects with an equally surprising lack of understanding of the subject you are taking to them. This too often results in people leading projects for industry on the same basis as they would approach smaller or domestic works and that inevitably leads to delays, misunderstandings and unnecessary avoidable frustrations. This article helps to clarify various roles and milestones which will stabilise and smooth the path to a successful conclusion.

What do Engineers do?

The best foundation you can have for strength is a strong rock, like granite. However it is unlikely to be the right shape and rock is not easy to shape so what is the best sort of ground to have? Geotechnical engineering is a very big subject and often confused with structural and civil engineering. The answer to the question is ground with sufficient strength to be able to take the weight you wish to impose on it. The geotechnical engineer will be able to tell you what you have got by taking samples, measuring the compressive strength and analysing the materials sampled.

Structural engineering is simply about structures. Civil engineering has become associated with altering the shape of the landscape but its origins quite simply emanate from the civilian end of military engineering.

I divide it up into two categories for the purposes of building and construction. Above ground is everything which is factory prepared and brought to site to be erected and below groundworks, which include all the services works, preparations, slab and foundations works, comprise the onsite preparations.

The structural engineers need metallurgists and the civil engineers need geotechnical engineers. This latter part is something which vanishes into the mists of time until you want some work doing which involves the floor or beneath it so when the information is published at the very outset of the project it usually disappears into the groundworks designs and never re-emerges. Make sure you always keep a copy of it. If you want to develop the site in future, it is the first thing the engineers will ask you for.

Before anything can be constructed on land (or below water) you have to establish exactly what you are building on and whether or not it will support the weight of the proposed structure.

I am amazed at how many experts there are in this field who are prepared to take massive risks and place amazing confidence in the properties of concrete even after 60 years of use. It’s a bit like assuming Blondini’s tight rope would be as good today as it was the day it was put up and then deciding to go for an afternoon stroll across it in ski boots.

Ground moves, it’s as much alive as you or me, there are hundreds of small tremors and vibrations at work all the time and this has an effect on geotechnical engineer new zealand everything we do or make. To just assume it will be safe to erect a mezzanine floor on a concrete slab is an unsound decision which could be costly. The same applies to shelving and racking especially if you intend to erect it on a mezzanine floor. If you load it to full capacity without knowing what you are doing you could be applying the equivalent of a stiletto heel load on balsa wood and we all know what stiletto heels do to lino and timber floors!

I was shocked after structural engineers had stated that a former canal side engineering works should have the floor strengthened that the directors of the company overruled the structural engineers and refused to pay for the works to be carried out. They went on to build cantilever racks designed to take 20 tonnes a bay onto a cracked floor stating that they had done the same at other locations and never had any problems. It’s like driving south on the north bound carriage way at 2.30 in the morning in thick fog and saying it is safe just because you can’t see anyone else and you are driving slowly!

Why does Pisa lean?

When we build load bearing structures these connect inevitably to the ground and that is where, with the aid of gravity, the full force is finally taken. You can make most things stable and perfectly able to accept very heavy and extreme loads. Steel will float if it is designed to do so and sink and re-surface again. Air will support metal. Groundworks are every bit as important and there are many ways of finding out what is going on in the ground. The leaning tower of Pisa is an amazing and famous example of problem ground. There was much argument and discussion regarding the work to save the tower from falling over completely and in particular how much of the “lean” to preserve in the reconstruction works. The answer was they reduced the lean by approximately 1.5 degrees to just short of 4 degrees and it leans because the ground is very weak and unstable. It was constructed over a substantial period of time which probably saved it in a period when little was understood about foundations. There were a lot of corrective building works which in fact make the tower curved as well as leaning. This is fine as a tourist attraction but you certainly do not want it in your factory!