(Fairly easy) Estimating the investigative cost of a catastrophic engineering failure

I blogged recently on the difficulty estimating the cost of forensic engineering investigation (Ref. 1).  The item included a tabulated assessment of the ease or difficulty estimating the cost of a possible 16 or more steps in an investigation.

You could be excused for thinking that the more catastrophic the engineering failure the more difficult estimating the cost to investigate the cause.  But, this is not necessarily the case at all.

I thought of this a few days ago when I received a report that is being circulated on the internet about a 13 story residential building collapsing in China in June 2009 (Ref. 2).  Take a look below; it’s quite a sight to see a multi-story apartment building lying on its side.

Why would it be fairly easy to estimate the cost to investigate the cause of the catastrophic collapse of a 13 story building?  Surely not easy, you say.

Because reading the documents – one of the first steps in a forensic engineering investigation, would identify the type of foundation – piles, supporting the building.  A simple site visit and visual examination would then note the blunder made on site.  Based on these two simple tasks, it would be easy to hypothesize the cause with considerable reliability.

For certain, a fairly standard investigation of the foundation soil conditions would be carried out to confirm the hypothesis – if, in the unlikely fact, the documents did not contain this soil data.

It is fairly easy to estimate the cost of these particular forensic engineering investigative tasks:

  • Document review,
  • Site visit, and
  • Standard soil tests – if the soil data was not already in the documents..

By way of further comment, an experienced professional engineer would recognize   that a basic foundation engineering principle had been violated, that of excavating and undermining the foundation on one side – this alone could cause the problem if the excavation was deep enough.  Then, making the situation worst by piling the excavated soil on the opposite side and surcharging the foundation.  The rain made the situation worse still by increasing the surcharge weight of the excavated soil on the ground and possibly reducing the strength of the soil beneath the ground surface.

The fact of the piled foundations would tell the engineer that the soils near the surface are weak adding further to the effects of the undermining and surcharging.  Piles simply carry or transfer the weight of a structure/building through weak soils to bear on stronger soils at depth.

Violation of this simple principle – undermining one side, surcharging the other, would leap off the note book page containing a sketch of a cross-section through the excavation, building foundations, the normal ground surface on the other side, and surcharge pile on the ground.  Never mind a note book – draw the sketch on a cigarette package, the violated principle is that obvious; I don’t smoke but that’s what people use to do.

A similar principle is at work prompting any one of us to be careful walking too close to the high, steep bank along the shore of a lake or river lest we fall in like the Chinese building fell down.

These kinds of catastrophic failures have also occurred in Canada, and estimating the cost of investigating the cause is sometimes easy.

For example, the failure of the nine story high Transcona Grain Elevator in Winnipeg in 1913 – you can find on Google.  The elevator failed – and leaned over 27 degrees, while being filled with wheat.  The wheat added weight to the foundations such that the bearing capacity of the supporting soils was exceeded.  Reading documents, a site visit, and a fairly conventional – and fairly easy to estimate, geotechnical investigation of the foundation soils would confirm a hypothesis of bearing capacity failure.

So, estimating the cost of investigating the cause of a catastrophic failure is not always difficult.  And, if you don’t mind, I would like to say that estimating the cost of investigating a simple failure is not always easy.


1. Difficulty estimating the cost of forensic engineering investigation.  Posted July 23, 2013


2. Chinese multi-story building failure


Anybody who bought a condo here sure has a problem.
Talk about a collapsed market!

Collapsed 13 Story Buliding China 1

(1)  An underground garage was being dug on the south side,  to a depth of 4.6 meters.

(2)  The excavated dirt was being piled up on the north side,  to a height of 10 meters.

(3)  The building experienced uneven lateral pressure from south  and north.

(4)  This resulted in a lateral pressure of 3,000 tonnes, which was  greater than what the pilings could tolerate.

Thus the building toppled over in the southerly direction.

Collapsed 13 Story Buliding China 2

*First, the apartment building was constructed.*

Collapsed 13 Story Buliding China 3

Then the plan called  for an underground garage to be dug out.
The  excavated soil was piled up on the other side of the  building.

Collapsed 13 Story Buliding China 4

*Heavy rains resulted in water seeping into the ground.*

Collapsed 13 Story Buliding China 5

The building began to tilt
Then it began to shift and the  “hollow”  concrete pilings were  snapped due to the uneven lateral pressures

Collapsed 13 Story Buliding China 6

And thus was born the eighth wonder of the world.

Collapsed 13 Story Buliding China 7

If the buildings were closer together it would have resulted in a domino  effect.

Collapsed 13 Story Buliding China 8

Collapsed 13 Story Buliding China 9

Collapsed 13 Story Buliding China 10

Collapsed 13 Story Buliding China 11

Collapsed 13 Story Buliding China 12

Collapsed 13 Story Buliding China 13

Collapsed 13 Story Buliding China 14

Collapsed 13 Story Buliding China 15

Collapsed 13 Story Buliding China 16

Collapsed 13 Story Buliding China 17

They built 13 stories on grade, with no basement, and tied it all down to hollow pilings with no rebar.


Are professional people, like children, learning what they live?

If recent surveys of ethical practice in the workplace are any indication it seems that we as professional people must be on guard all the time against undue influences.

This occurred to me a few days ago when I read two recent posting by Chris MacDonald, a chap who blogs on business ethics.  The postings are entitled:

  1. Do you report unethical workplace behaviour?
  2. The state of global corruption

I was struck by the high percentages of observed unethical behaviour in the workplace.  For certain, some of it quite small stuff, but, it starts there.  Ask some of our politicians and captains of industry.

In the one posting, Chris reports, “A new study of ethics in Canadian workplaces suggests that 42% of workers have witnessed ethical breaches in the workplace, and nearly half of them failed to report such misconduct”.  He goes on to argue that it may be higher.

In Chris’ second posting, he reports on the findings of a world wide survey of corruption in 107 countries.  Why worry about what is going on in all these countries, you say?  Well, Canada is one of the countries.  Guess what percentage of Canadians think the following institutions are either corrupt or very corrupt?:

  • 62% think Political parties are either corrupt or very corrupt
  • 48% ……. Business ……
  • 47% ……. Parliament ……
  • 39% ……. Media ……

Interesting, eh?

If this perception of Canadians is only partially true, and extends to other segments of our society, it’s a toxic place we be in as far as ethics are concerned.

How is it possible to practice ethically with so much mischief about?  Continue to stand guard as most of us have in the past.

How does this relate to forensic engineering investigation?  Well, I’ve been asked in the past to write a forensic report that supported an argument – I didn’t.  And, I was asked recently to investigate a problem and “…show that we are right” – I explained that’s not how it works, that the justice systems requires us to be thorough, reliable, and objective.  The person accepted that, a little embarrassingly – they just didn’t understand.

For the rest of Chris’ postings – they’re a good read, and they remind us to be on guard:

On ethics in the workplace:

For the rest of this item, visit … http://www.canadianbusiness.com/blogs-and-comment/do-you-report-unethical-workplace-behaviour-chris-macdonald/

On corruption in the world, including Canada:

For the rest of this item, visit … http://www.canadianbusiness.com/blogs-and-comment/the-state-of-global-corruption-chris-macdonald/

I introduced you to Chris’ blog last April in a posting of my own at: