Structural engineer

Another Faulty Tower – John Cleese, Where Are You ?

2009-10-07:   A Cautionary Tale for Clients/Client Organizations … from across the Pond … and a serious lack of Technical Control over the processes of Building Design and Construction …

Where there is no proper Technical Control … can there ever be an appropriate safety factor to incorporate into the design  ?

And before it’s too late … how is it possible to establish that there is no proper Technical Control ?

An artistic rendering of the oval-shaped Harmon Hotel & Spa, in Las Vegas, Nevada (USA), at its original designed height of 49 stories.
An artistic rendering of the oval-shaped Harmon Hotel & Spa, in Las Vegas, Nevada (USA), at its original designed height of 49 stories. Click to enlarge.

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2009-10-26‘Who’s to Blame for Faulty Foster Tower ?’ … by Tony Illia, Architectural Record (archrecord.construction.com) …

Despite the recession, CityCenter continues to rise on the Las Vegas Strip, with several buildings scheduled to open later this year.  One project that certainly has not turned out as planned is the 400-room Harmon Hotel Tower, designed by Foster & Partners, which will be nearly half its estimated height due to construction defects.  The problems have escalated into finger-pointing between project parties, resulting in legal actions and project reviews that are still under way.

The 28-story oval-shaped high-rise broke ground in July 2006.  Pacific Coast Steel, a San Diego-based subcontractor to Perini Building Co., improperly installed reinforcing steel inside link beams on 15 floors, a Clark County Building Department investigation revealed.

The problem should have been caught by inspectors, but a third-party California inspection firm, Converse Consultants, falsified 62 daily reports between March and July of 2008, stating that the steel was properly installed, according to county inspectors, who also missed the problems.

The defects were discovered in July 2008 by the project’s structural engineer, Halcrow Yolles Structural Engineer, temporarily halting construction and leading to the Harmon’s redesign.  Owner MGM Mirage declined to disclose the cost of the errors.

This April, Pacific Coast Steel paid $14,105 in fines after a Nevada State Contractors Board investigation discovered ‘workmanship’ issues.  As part of a settlement, the firm did not admit fault.  In August, Converse Consultants was suspended from seeking new work in Southern Nevada for six months, and its inspectors had their qualifications revoked or suspended.

The subcontractor says Foster & Partners is partly to blame.  “Perini stands by its opinion that design conflicts contributed to the Harmon Hotel structural issues and that portions of the structural drawings, as designed and permitted, contained elements of reinforcing steel that could not be installed as drawn,” said Perini President Craig Shaw in a statement.

The Harmon’s design called for pouring top portions of 2.4m thick link beams at the same time as the floor slab, which is a tricky procedure given the tight and exact spacing of reinforcing rebar.  However, the contractor made installation adjustments in field.  Stirrup hooks, in some cases, were spaced incorrectly and extended past the floor, prompting workers to cut them off so it wouldn’t show, the county inspectors say.

Corrective work and a structural building redesign are in progress.  The building will safely reach 28 stories; pricier work would be needed to meet the originally designed height of 49 stories, say project officials, who would not elaborate.  Foster & Partners declined to comment for this story.

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Architectural & Structural Engineering Design for Robustness !

2009-07-11:  Earlier in the year … a certain non-native English speaking colleague of mine, who is very active in European and International standardization work (and has very good English !), had never heard of the word ‘robust’.  She just could not get her head around either the word or the concept … and thought I was making it all up !

Fast forward a few months … and as a long-time member of the International Association for Bridge & Structural Engineering (IABSE), an occasional ‘freebie’ lands on my desk.  This one was a real treat !

Published by IABSE in Switzerland … Structural Engineering Document #11: Design for Robustness … was written, in language accessible to both structural engineers and architects alike, by Franz Knoll and Thomas Vogel.

The objective of these Structural Engineering Documents is to provide in-depth information to practicing architects and structural engineers, in reports of high scientific and technical standards, on a wide range of structural engineering topics.

Check out the IABSE Website … http://www.iabse.org/publications/orderform/ … and get yourself a copy … pronto !

 

In previous posts concerning Areas of Rescue Assistance in Buildings, for example, I have often referred to robust, fire resisting construction

Robust (in the above specific context):  Structurally hardened, and resistant to severe mechanical damage during the fire and for a period of time afterwards, i.e. the cooling phase.

The further development of Fire-Induced Progressive Damage … will inevitably take place within wider considerations of Robustness.

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