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Planning for structure repair work

posted Apr 4, 2011, 7:53 AM by jeffery jim   [ updated Jul 7, 2016, 10:17 AM ]

INTRODUCTION

Recently, structure repair work has been one of the most newest most demanded disciplines in local construction industry aside from the industrialized building system (IBS). Many inexperienced general contractors got the contracts to conduct structure rectification and rehabilitation works but the main question is how do they even justify their planning and their pricing to this new field of work in the industry? Will this effect their performance as they are vague in regards to the task and professional level lies ahead?

Yes! These general contractors are indeed vague in regards to planning especially the sequence of the whole project  although the contracts signed are PWD203A 2007 based. Let us shade some lights in regards to this matter from my past experience as the Resident Engineer for many structure repair and rehabilitation works. Aside from that, we shall discuss the problems arises from many prominent and small timer consultants when they are engaged with structure repair.



PLANNING, A SIMPLIFIED  LITERATURE
Planning for a project is essential but who can review and endorse them? As known to many, work program submission is nothing but another less important annex to the binding of contract by many justly defined as inexperience contractors who are profit oriented. Microsoft Project or Primavera Project Planner 3.0 or 6.0 are software to conform to the instructions as specified in most Instruction to Bidders (ITB) and project briefs regardless of the project size and complication. The submitted work program usually remains as dusty ad-hoc and forgotten appendix to the contract document and rarely these plannings are tracked to satisfactory as in most progress or interim reports.

Planning also can be a tactical substance for those who are familiar with financially hungry contractors. It is not a taboo to do so if one knows how to deliver a low physical work with high financial weightage as long as it comply with requirements.  This can be easily spelled out using planning tools, instead many still use lip service with Bill of Quantity spreadsheets and skyward-picked-assumption for resources and period of execution. This can assist the in-house quantity surveyors, procurement coordinators and other professionals to read the unified language from planning tools instead of various translations in terminologies and hand physical gestures which may lead to misunderstandings and incoherent.

Awkwardly this still happen even though planning is the prime key to success of executions regardless in construction industry or even in personal life. Therefore it is appropriate why many planners blurted out the concept of ”90% on paper, 10% on executions”; which clearly identify that planning is a vital manifesto and to those with clear conscience that plannings are not futile if appropriate plannings are in place,  risks are identified and some are highlighted, calculated executions at achievable rate, leverage of resources and most important, the handling of cash flows for multiple projects for a contractor.

Planning work concept in construction often rendered differently where at most time it is about the method to compute a gantt chart out from a scheduling software. Indifferent to many successful managers and senior construction players, planning work is more than that. For an ISO accredited company, the main frame of plannings are in the Project Quality Plan itself and it houses multiple plans which usually consist of project execution planning, HSE planning, procurement planning, resources planning, financial planning, traffic and communication planning and the consultant-favorite planning; the Inspection and Test Plan.



STRUCTURE REPAIR PRINCIPLES FOR DUMMIES
Structure repair is not just another construction field as presumed by many and is not similar to conventional construction regardless of the construction contract nature itself. Structure repair work is a field which requires professionals with analytical thinking and being very articulate in many principles outside of construction and structural engineering.

The main essence of structure repair is all about forensic work in order to determine the actual and factual cause of degradation of reinforced concrete structure member’s quality. To cut short, the engineering inputs are vital to summarize the reasons of it’s failure, identifying the mechanisms of ingression and those detrimental agents, the physics and method of ingression and transgressions as well as fusion in electro-chemical reactions, material properties, the understanding of basic requirements in the light of relevant specifications and to ensure that the appropriate solutions are applied to tackle the problem within the agreed and affordable budget.

The main concept of structure repair is to treat and rehabilitate the structure as a whole when it lapsed its serviceability period or when certain structure members has lost it’s durability, robustness and probably has lapsed it’s permitted service limit state and entered ultimate limit state due to defects and degradations.

Structure repair work is not similar to new construction work and therefore at most time, the repairs are performed without halting the activities at the adjacent (safe distant with buffers) venues as a whole, instead these were orderly orchestrated  to ensure the forms are remedied and functions keep on going. This is the significant difference and have defied many contractor from smooth work progress when their planning is not even close to the reality in structure repair works.



SETBACKS DURING STRUCTURE REPAIR WORKS
Among the most important essence in structure repair work planning is to quantify to approximate the said-to-be intangible quantity of percentage and degree of damages. This is true in many cases due to the inability to detect  the main fault that caused the deterioration and the agent that caused it.

This itself would have lead to controversial quantity issues which would lead to argument and to conclude the type of repair persisted by the structure consultants. This has been the main setback and idling period during the contract and this would rule in the high possibilities in changes of methodologies which imply various proposed materials. This would prolong the work from commencing at the project site. Among the common failure of the contract, which I would amplify as the nullification of the contract would be the contradictions of contract documents. An easy cross reference would usually shows that, the quantity mapped are not similar to the Bill of Quantity and the defect mappings at most time are not related to the finding/discovery at site.

Aside from the quantity of work that have gone burst  from the specified relative bill of quantity for a lump sum contract work, the methods of requisitioning data during the investigation might impair the whole concept of repair where the proposed repair are not suitable for the actual defects at site. As an example, chloride attack issues are not to be answered and resolved with methods of remedial which are only for carbonation cases (Please refer to BS EN 1504 as guidance). It may involve the appropriate method in priming as preparation however it does require another set of extra work which is passivization of the chloride ion which have induced the corrosion of steel bar since chloride ions are well known to remain on affected concrete and able to penetrate the newly well grouted structure members. Aside from that, it would be an argument for some inexperienced Resident Engineers to argue the claim of reinforcement bars used are lesser (pitting of reinforcement bars due to chloride attack would result in minimal lapping of reinforcement bars while corrosion due to carbonation would effect the whole exposed section of reinforced concrete structures) than specified in the Bill of Quantity (even though clearly it is a lump sum contract). Contractual issues as mentioned should be handled by professionals who could mediate and resolve the whole issue to ensure work are verified and justified or else, the main reason of contracting for profit would end up with cash flow problems due to delay in claim approval.

Another good reason why your planning look too crowded with multiple critical path relationships in your gantt chart and network diagram. Did you realize that your planner has actually being a procrastinator indirectly to the project?  Your planner and coordinator owe you an apology. Not many and even consultants would not understand why some work could be done faster than the projected work program. In the case of material selection, if you have selected non-shrink grout as a method to remedy at many cases, the JKR standard specifications for building work 2005 for concrete work can be superseded. The Table 10 – Minimum periods between concreting and removal  of forms can be easily justified and give the team the time saving of almost 18 days? The compressive strength from the grout easily achieves the equivalent strength of 21 days from normal G30 ready mix concrete in just 3 days?

Structural repair work are usually conducted on sections of the structure which are still in use when they have yet to pose significant danger to it’s inhabitant. Structure members which have just entered the propagation period may not set off a sudden failure for reinforced concrete structures as they normally do during fire. Therefore it is quite normal to carry out repair work with inhabitants and their dynamics at adjacent areas which buffered from peril or fatality. This involves traffic management; both internal and external. Engaging in coordination would be a painstaking task since the contractor have to deal with the client, third party, users, and public who are appropriate to be labeled as obstinate at times. These would caused time lost of resources if the site agent is not responsive enough in leveraging the resources to catch up with time lost. Aside from that unscheduled and unforeseen activities (on the client side) also may lead to stalling of works due to the client’s inability to give exclusivity for job continuation. Abruption of works due to this factor can be time consuming and even lead to rejection by supervisory team due to conformity to specifications.

Aside from that, the coordination of work is really important to ensure that there are no encroachment by other handymen or subcontractors during the critical period of the structure repair work to avoid contamination or substandard in delivering product during realization processes. Aside from encroachment, preservation of work done which integrates part of other installation at the later stages should not be ignored. In some structure repair work, pre-installation of other specialized goods are needed and it is a critical factor to ensure that these goods are installed and completed at due time. Coordination between the contractor and the consultant often not foreseen as a critical factor in eliminating the idling time when this has been one of the highly identified contributors to time lost for sequence-impact task where a hold point inspection is needed and established for verification, justification and documentation.

Aside from the lack of fundamental understanding of how delicate a structure repair work can be, usually planning done by inexperience general contractor can be useless. It is always a good practise to come back to the forensic work and/or site surveillence to ensure that progress of work are not limited due to working ambient. The classic example would be from priming work to the reinforcement bar. The allowance given to conduct priming would be at the humidity of under say, 80% (as per manufacturer’s instruction). Therefore the planning schedule should reduce the factor of priming at overtime for external structure and working/peak hours (if work are to be carried out in the factory’s processing rooms).

Another problem which most general contractors failed to identify is the relation of logistics and statutes during procurement. It is easy to determine whether the access to the site or delivery could be established prior to purchasing and it is even easier when procurement is done by experienced logistic companies. The cost saving factor which made many contractor a little bit selfish and try to D.I.Y purchasing can be a doomed  effort.  Among the  famous purchasing blunder would be buying materials off factory only to find that these materials could not be air freight due to their nature as a flammable substances.

The inability of material coordinator  will spell disaster and time lost when materials cannot be delivered on time. This way procurement planning is vital to ensure continuity of work may not seize and depend so much on local market if the sought after items are special items instead plan for arrival accordingly as set on the procurement plans.



A LEGAL NOTE CAN BE A SUICIDE NOTE

Many general contractors who have been involved in structural repair might not took into account the most important aspect of their contract and legality of their work. After a well-planned activities run smoothly, it comes to the point of handling back the project to client for issuance of Certificate of Practical Completion (CPC). Now, here is the spoiler to most general contractor who try to save cost without employing structure repair specialist.

General contractors are nullified from most warranties of the system where most manufacturers will not disclose this to them during the purchasing. This is because the manufacturers are selling their material to the contractors as consumers rather than giving guarantee since it has always been the basis that guarantee are only given and applied to works done only by authorized applicators/specialists.



Most contractors have to give guarantee to the client that their system should function during the Defect Liability Period (DLP) and for at least ten years. If you are one of the SMART general contractor and did a lot of structure repair work, probably this is a time for reflection whether  you are protected by the manufacturers  after using their products. All you can do is to hope for devine intervention, after all; you have executed works in the given time frame but did you PLANNED  to get yourself out of the equation of being possible risk takers? Hope that when any general contractor who finished going through this review, the cost saving act is not going to backfire any of you.

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