Asahi Kasei – Faulty Yokohama Condo Pile Installation

If you’re living in Japan, you’ve most likely heard about the latest construction scandal involving the modification/falsification of pile installation reports for a large Yokohama condominium, Park City Lala Yokohama, and subsequent tilt. Although the media attention is currently being focused on Asahi Kasei, it’s important to note the 3-tier contracting hierarchy in this fiasco:

– Sumitomo Mitsui Construction Co., Ltd. (Primary contractor)
– Hitachi High-Technologies Corp., (Subcontractor)
– Asahi Kasei “Kenzai” Construction Materials Corp., (Secondary subcontractor)


Initial Discovery

A resident of the condo in question became concerned as early as November of 2014, when noticing a roughly 2 centimeter height difference in hand rails in the public hallway connecting the west and central courts of the complex.

When this was brought to the attention of Mitsui Fudosan Residential (condo-owner), they simply blamed it on the 2011 Tohoku Earthquake and continued to evade the issue for almost a year until they were practically forced to action by Yokohama city.

Note here that the construction warranty against defects is 10 years. Park City began selling condo units in 2006 and finished the project by December of 2007. Had the problem gone unnoticed another 2 years, any payout or compensation deal would have been significantly harder to reach.

So in a way, these folks are lucky.

Cause of Tilt

In the subsequent investigation carried out by Mitsui Fudosan and Sumitomo Mitsui Construction Co. in late September, the following problems were unearthed (literally):

Faulty installation of piles. 6 piles out of 473 failed to reach bedrock, and 2 didn’t reach the required depth within the bedrock.

Proper and Improper Pile Installation - Left and Right Respectively

Proper and Improper Pile Installation – Left and Right Respectively

Modification of ammeter data. Records of the magnitude of the pile-torque – used to assess whether or not a pile has reached sufficient bedrock depth – for 38 piles was found to be modified.

Modification of flowmeter data. Flowmeter data – used to determine the volume of concrete injected into the borehole to fill cavities between the pile and borehole – for 45 piles was found to be modified.

On September 24th, Sumitomo Mitsui Construction Co. Ltd. informed Asahi Kasei Kenzai of the above result of their preliminary investigation.

Who’s to Blame?

Directly, Asahi Kasei Kenzai – as they were the ones who were subcontracted to carry out the pile installation.

Of course, each of these companies are “big boys” in that they should be expected to take responsibility for their own mistakes, screwups etc, but again, it’s important to note the kind of financial and timetable-related pressures those at the bottom experience, as well as the professionally understood risks of all the firms involved in a project of this magnitude.

When it comes down to it, the final contractors are the ones under the most pressure to get the job done on time. When clients are given an exact date as to when they can move in to their new apartment flat, it’s generally not an option to tell them they’ll have to wait a few more weeks or months as “things got delayed”.

They’ve paid handsomely (many no doubt incurring heavy debt) for their new home, and as would be expected, are most likely waiting eagerly for this date. So naturally, the top-tier contractors are continually putting pressure on those at the bottom (from their air-conditioned offices) to get the job done on time to ensure a smooth timetable.

As far as accountability within Asahi Kasei Kenzai, we don’t know – and may never know – whether the foreman in charge acted alone, or on the orders of superiors when falsifying reports. However, here’s what we do know (pertaining to civil-engineering projects; residential requirements are different):

– All piles must reach bearing stratum (bedrock).
– Individual borehole investigations are required to determine bedrock depth and hardness, as bearing stratum often isn’t at the same depth across a wide area.
– These borehole investigations are expensive; said to be between 100,000 and 200,000 yen per borehole, depending on depth.

Another factor to consider here is that pile lengths are set at the factory based on borehole investigations conducted beforehand, which means that unless the same foreman was responsible for those initial data-readings as well, there was at least one other higher-level individual involved.


The question now is, with this kind of incentive to cut corners, along with unrealistic expectations, harsh deadlines, and the possible involvement of multiple individuals, can we really pinpoint the blame on any one person or even company? And more importantly, what can we do to ensure these things don’t happen again?

Here’s a quote from a twitter user:


Translation: “Although the depth to which the piles are driven are determined by data records taken onsite by the pile-installation contractors, I can’t think of any practical way with which to verify whether or not these records have been modified (after the fact). It makes you wonder just how many piles used to date around the world aren’t actually reaching bedrock.”

I wondered the exact same thing.

In other words, because piles are hidden deep underground, largely inaccessible, how can they practically be double-checked in an economic and efficient manner? What methods can be used as a fail-safe aside from a third party simply looking over the data but ultimately having to take the contractor’s word, trusting that he knows what sort of s**tstorm can brew from falsifying data?

Practical solutions for residents can be broken down to the following 3:

1. Repair, replace, and/or reinforce piles. This option is largely seen as near impossible due to the nature of the job. The first and second floors would need to be completely gutted, leaving only the structural columns, beams and walls, to allow pile drivers and other heavy machinery in to do their work.

And after all is said and done, will residents be satisfied? And more importantly, from a business perspective, will the general public be satisfied with this course of action, and will it be enough to repair the tattered image of these construction and real estate firms?

2. Demolish and rebuild the entire condominium from scratch. This is also largely seen as too impractical due to the time it would take. All residents would need to be temporarily relocated (could be several years), and there would be a sizeable physical and emotional toll.

3. Buyback. Mitsui Fudosan would buy back all the condos and subsequently demolish the structure. On the face of it, this option would cause residents the least headache, but it would also destroy the social community built up by residents up until this point.

In the end, there really is no option that could be seen as a “bargain” for the owners (unless there happened to be an owner who had been desperately wanting to sell and was praying for just this kind of incident so he could haggle for above market value). It’s kind of a lose-lose situation for everyone involved. But what’s done is done, and all we can do now is hope the Japanese construction industry will wake up and turn a new leaf.


Asahi Kasei – October 20th, 2015, press release
Safety Japan on the faulty pile installation – Article by Hosono Tooru, a free-journalist covering construction and architecture.

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