Thursday, August 07, 2008

MRR2 FAILURES: Would the TRUTH be told?

Yesterday, sun2surf columnist Citizen-Nades in his article "Former minister wins uncivil war" wrote:

[quote]

The asking price by the new firm – Leonard Andre and Partners (LAP) was a mere RM18 million – just RM6 million more and they were providing space-age technology – carbon-fibre to save the cracking pillars.

Can we anticipate someone standing up and saying: "Yes, I take responsibility. It was me who approved the use of carbon-fibre technology which had never been tested or used in Malaysia previously."

[unquote]

I would like to tell Nadeswaran that Carbon-Fibre Technology (CFRP) is not space-technology and the proposed methodology for strengthening the reinforced concrete structure using CFRP is not something new and surely is not a space-technology, neither is it used for the first time in Malaysia.

The peeling of the plastic strap do not mean the strengthening works had failed. It is neither about taking responsibility for a failed technology or methodology. If ever we are to discuss failure, we should be discussing about the structural failures which was occasioned by the design failure during the construction stage.

How many of us gets to know the truth of the failure? To make matter worse, we have non-engineers who were fed with surreal knowledge of engineering design and construction technology. Equally we are puzzled by the statement made by Halcrow senior consultant (bridge engineering) Roger Bucky who said he had in 2005 advised PWD not to use carbon fibre straps because the plastic straps used to strengthen the pillars have limited ductility; but JKR proceeded with the use of the carbon fibre straps.

3 of the 18 carbon fibre straps on Pillar 18 had since peeled off.

Roger Bucky in his diagnosis attributed delayed ettringite formation (DEF) as the cause of the peeling of the straps.

For non-structural engineers they may think that DEF is some kind of a cancerous virus in structural concrete. So what is DEF?

Generally, DEF is seen as a form of internal sulphate attack. A number of factors such as concrete composition, curing conditions and exposure conditions influence the potential for DEF. DEF is believed to be a result of improper heat curing of the concrete where the normal ettringite formation is suppressed. The sulfate concentration in the pore liquid is high for an unusually long period of time in the hardened concrete. Eventually, the sulfate reacts with calcium and aluminium containing phases of the cement paste and the cement paste expands. Due to this expansion empty cracks (gaps) are formed around aggregates. The cracks may remain empty or later be partly or even completely filled with ettringite.

(Source: www.concrete-experts.com)

Self-desiccation of normal density (ND) high strength concrete may prevent delayed ettringite formation (DEF).

Was DEF as espoused by Halcrow the reason of the structural failures? It wasn't!

So what cause the failure? What caused the cracks in the crossbeams?

The investigation carried out by the experts into the cracking has comprised of both field investigations and design assessment. The field investigations included site inspections; data gathering; crack mapping; cover-meter tests, concrete strength sampling; chemical tests and crack width monitoring.

The design assessment comprised of both load assessment and structural analysis by a number of methods including Code Assessment, 2D Strut and Tie Modelling, and Non-Linear Finite Element Modelling. The analysis covered both construction phase loading (from temporary overhead erection loading used to erect the precast superstructure segments) and in–Service Phase loading from permanent loads and traffic.

Based on Site Investigations and Design Assessment, the primary causes of the cracking at the critical sections for the Typical Piers and Abutment B are a result of temporary gantry erection loading and early thermal and shrinkage cracking which occurred during the Construction Phase. These load conditions were far more onerous for the structure than any In-Service load conditions.

For the In-Service Phase, calculations (which was done by the contractor's consultant) using both traditional Bernoulli methods and by Strut and Tie methods have demonstrated that the Pier structure has more than the required capacity to carry the factored In-Service loads in-accordance with BS 5400 Code requirements. (However, the JKR audit team later discovered that the lap length of 40mm dia. bars were insufficient)

In the analysis the development of bond stresses in the reinforcing bars has been checked and found to comply with Code requirements.

The FE Model predicts that the Ultimate Capacity of the pier cantilever is in the order of 2.6 times the applied Nominal Loads, which far exceeds the Code required factor of safety (Note: Input parameters were not obtained from site but assumed by the contractor's consultant). Ultimate failure at this level of overload is ductile as required by the Code. Sudden failure would not occur even at this extreme overload condition. (Note: when requested, ductility factor could not be provided to the audit team)

This was the structural analysis reported. However, the recommended solution was not acceptable and was considered as superficial. The engineers wanted a comprehensive rectification methodology, which would ensure that the structural integrity would comply with the Need Statement and in accordance with the Government's Requirement as postulated in the Contract Document. JKR holds the contractor fully responsible for the default which constituted a breach of contract and wanted the contractor to make good the defective works in full compliance of the agreed design integrity.

Under the PWD From DB/T Contract Terms and Conditions, it was stipulated that the Contractor shall check the design and accept responsibility (Read Clause 2.3.2).

As stipulated under Clause 2.2 of the Conditions of Contract: "The Contractor shall be fully responsible for the design, execution and maintenance of the Work/portion of the Works for which the design have been accepted by the Government, and shall absolutely guarantee the Government independent of fault that the design, materials and workmanship for the Works or portion of the works is suitable for the known requirement of the Government."

Under Clause 2.6, The Contractor shall take full and unequivocal responsibility for the safety of the design and for the adequacy, stability and safety of all site operations and methods of construction.

And in Clause 2.7.1, the Contractor shall be liable for any damage to the Works occasioned by him in the course of any operations carried out by him.

Clause 2.8.4 states that, if there is any failure, either during the execution of the Works or during the Defect Liability Period, any remedial or repair works shall, in the opinion of the Project Director (Ketua Pengarah JKR) be urgently necessary for the safety of the Works or the public, the Government may employ and pay other persons to carry out such work or repair as the PD may consider necessary; and the costs and charges properly incurred by the Government in so doing shall be recoverable from the Contractor by the Government.

Nadeswaran posed the question: "Who is going to be held accountable for this monumental man-made disaster?"

Mr. Nades, who else? There is a contract and the contract had spelt out the terms and conditions. The German structural engineers had confirm it was design error. The British Halcrow had confirmed it was design fault. The Australian Consultant had reported that the causes of cracking were due to negligence in their design work which have resulted in the design failure. The primary causes of the cracks at the critical sections for the Typical Piers and Abutment B are a result of temporary gantry erection loading and early thermal and shrinkage cracking which occurred during the Construction Phase. Both of these design effects were in the scope of design works provided under the terms and conditions of contract.

So, who else should be responsible? Who is going to be accountable?

I'm sorry; it would have to be the contractor.

I hope Samy Vellu do not come up with another different version of explanation. Let's wait for him to tell us.




20 comments:

Kenny Ng said...

That's more detail about the cause of cracks. The design maybe is just for 3-4 lanes, but Malaysian drivers will line-up till 6-7 lanes during traffic jam just to jump Q, not only that, overloaded lorries & trucks also will give a big impact on it.

Where is the design safety factors?

CK said...

as long as cronies are involved, they will be protected if they are in the right camp.

tat's the pathetic fact. it's not once, not twice but third time now. just when are the BN gomen gotta learn?

bayi said...

"Under Clause 2.6, The Contractor shall take full and unequivocal responsibility for the safety of the design and for the adequacy, stability and safety of all site operations and methods of construction."

The contractor to take full responsibility for the design? Is this the usual and normal practice, Mave?

mohdhaslanr said...

Hai
I think the contractor will take a full responsibility for the design only if he the contractor was the designer itself (i,e, design & build) but in the case of MRR2 I am not sure if it was a design and built contract.
Regards

yok hoong said...

mav

thanks for the insight although some parts are too technical for a layman to understand. but the bottom is clear which is the contractor must bear the ultimate responsibilities.
will the authorities take the contractor to task? thats the key question and i am skeptical given the track record of the authorities.

have heart said...

haiyooo...i dont understand all this engineering thingy.but rather than put all the blame on the govt,i hope the govt gonna look through this matter and solve it asap since it involves humans life.

kittykat46 said...

Carbon-fibre technology has been used extensively in Japan and in the USA for post-construction strengthening of old bridges and buildings especially against earthquakes.

It is proven technology.
Its very high strength vs. weight (many times more than steel) makes it attractive to use for reinforcing existing structures without adding substantial additional weight.


However its still an unusual material to most civil engineers and contractors may not be well versed in how to apply it correctly.

moo_t said...

Apparently, there is an evasive maneuver from the BN government on behalf of the contractor (WTH!).

The MRR2 issues happen more than 2 years, but there

-------------
mohdhaslanr, you make me laugh. Did you read the whole blog? Did you notice Doc mentioned Clause 2.3.2?

Now tell me, you pay and sign the contract, ARE YOU GOING to manage the subcontractor under the main contractor! If otherwise, then tell me, what is the purpose of a agreement contract? Is it a toilet paper to you?

As client, you don't give it damn if the subcontractor f*ck up, because there is an agreement to follow.

If the main contractor careless about selection of subcontract, they must take ALL responsible. And whether the main contractor sign another clause with the subcon, that is their job! If main contractor didn't sign clause to cover their own ass from the subcontractor shoddy works, nobody can help!

Anonymous said...

THE TRUTH IS CRONIES MADE MILLIONS AND THE HIGHWAY WILL DEFINITELY COLLAPSE AND KILL HUNDREDS.

HIGHWAY ROBBER

hasilox said...

Good analysis.

The previous RM70m repair was paid with taxpayers' money. If the contractor can actually make money out of their mistake, where is the motivation to rectify?

Is this another project built using taxpayers' money, profit to concessionaire and decades of payment by taxpayers?

Anonymous said...

mave,

1)pls read the sun's report again....i don't think that Roger Buckby attributed the cause of the CFRP peeling off to the occurrence of DEF. I believed he meant DEF contributed to the earlier cracks that led to Halcrow being appointed to investigate the cause.

2)If the earlier cracks were due to design inadequacy,I concur with you that the "Design & Build" contractor would be responsible.But for the repair work, if the German repair Consultant appointed by JKR ie LAP recommended an inappropriate repair method(allegedly by Roger Buckby),why should the contractor be responsible in this case?? You seemed to be contradicting yourself here. We need to have an open mind on this.

Fair comment.

seefei said...

early thermal shrinkage? the concrete temperature must be too high during concreting causing early formation of entringgite at a later stage!!

Maverick SM said...

Kenny Ng,

The design has taken into consideration the live loads, and include distress conditions.

CK,

My emphasis is on design engineering and contractual terms and conditions and did not cover the aspects and considerations regarding the political management.

Bayi,

Ya, it is what is stated in the contract.

Mohdaslanr,

I can assure you that the contract is PWD DB/T -Design and Built. I have the contract numbers.

Yok Hoong,

Ya, it is technical and I do not expect the general populace to understand the technical issue. But I want to provide the essence of the failures so that the people have a true knowledge.

Moo_t,

I think the cabinet members were not feeded with the true story.

Highway Robber,

That's not in this discourse.

Hasilox,

That, the political masters and PAC must explain.

Maverick SM said...

Fair Comment,

I had a day earlier provided with the photographic proof of the crack patterns to show that the original cracks was never due to DEF of which Halcrow attributed it. It was stress cracks from direct loadings in access of capacity and also attributed to the provisions of the lappings of steel bars and the issue of insufficient anchorage into the crossbeam.

You have failed to understand the contract: the contract states that the contractor is responsible for the integrity and safety of the structure. The contract provides that, in the event the contractor did not carry out the defect rectification, the Govt can engage a 3rd party to rectify, but the responsibility and liability remains with the main contractor.

You failed to understand that the repair work was merely strengthening due to design failure and the project and the structure is still under defect liability guarantee and warranty. There is a 5 years design warranty and in the case of inherent defects in design it is perpetual period.

I suppose you do not understand the contractual rights and obligations of the agreement.

Maverick SM said...

SeeFei,

Your theory is correct; but this is not the case here. It was about under-design provisions and recklessness of overloadings during the construction phases and the problem of the loadings imposed by the gantry cranages during construction stage.

Anonymous said...

Mave,

1) You missed my point on my comment (1); the sun's rpt never mentioned that the CFRP peeled off due to DEF or attributed to this from R.Buckby.This was your own interpretation,no? Read again !! ! Nevertherless,you are entitled to your opinion on how the earlier cracks evolved and I hv not commented on that,eventhough I would give the probability of doubt to Halcrow for the in depth study they hd conducted on the concrete samples taken from site.

2)You displayed several crack mapping diagrams in your article,so I assumed you hd your contact probably within JKR circle too.Surely then,you must know the politics(it's been revealed anyway by Citizen Nades in the same sun's editn too)involved at the highest level too.So how sure are you that the contractual rights had not been compromised by the govt's(read certain top JKR gun) own folly of "bulldozing" the repair using their preferred repair consultant???If things are ever so straightfwd,lawyers will be outta job!!! Get it???

3)BTW,I agree with you that using carbon fibre technology for structural repair works is nothing new in Malaysia, BUT in MRR2,LAP introduced "prestressed" carbon fibre technique which have never been used in M'sia( to the best of my knowledge),what more on a large scale repair like this.So, you may want to tell Nades the right fact?

Fair comment,

Maverick SM said...

Fair Comment,

Thanks for your clarification; and I didn't miss your point.

My subject is about the structural failure, not the repair defects. the repair defects is a minor issue and the repair specialist will be responsible to make good.

But you have not considered the Clause 2.8.4 as stated above. If there is a failure during the execution of the work or during defect liability period and the contractor fails to make good, the PD has a right to engage a third party to carry out the works and the contractor shall still be responsible for the original defect.

I am a research engineer and I have been doing research on structural failures in bridges and buildings for many years. The information sourced are available in Universities (local and overseas, particularly in Australia) and from other thesis done by many under-graduates and post-graduates everywhere who are also doing similar research.

I must say that CFRP and prestressing technique are not new in Malaysia and there are quite many prestressing companies doing such work.

What I wrote was based on the law of contracts and from documents available in the public domains including universities

seefei said...

dear SM
sorry i din read yr earlier posts. my apology. from the crack lines pattern drawn on the graph paper, the crack lines look like shear crack. design inadequacy cannot be ruled out.

however, concrete performance depend on the dual interaction between the concrete and the reinforcement. hence, a study of the hardened concrete is necessary. Maybe the use of petrography will shed some light on the issue. petrography is a microscopic assessment of the concrete thru thin slice. workmanship history, material usage, additive usage, water cement etc can be evaluated.

a check on the reinforcement sizes and spacing is also necessary. intrusive and ndt should be carried out.

if you are pursuing the "overloading" theory, evaluation of the progress photograph is necessary to understand the loading scenario during the construction process.

my 2 cents worth...

Maverick SM said...

SeeFei,

You can be assured that all the tests including petrography was done and analyzed and the result gave the same conclusion.

enquiries said...

should use macalloy or dwideg bar with an open anchorage system. the original consultant did not take into consideration maintenability issue.