Category: English Version


Introduction

The ISO 9000 standards were the result of actions and needs for industrial processes during World War II. When the war was over, concepts such as inspection and control were established. Production and products were being consistently controlled. By then, the word “quality” was associated with “conformity”, i.e. control and command of production.

By the end of the 50s, the approach that used inspection processes to ensure quality continued developing in theUSAquality requirements procedures and specifically “Quality Program Requirements” MIL-Q-9858 applicable to military industry. Afterwards, NASA promoted the evolution of the concept of Inspection to systems and processes to guarantee quality.

The procedures destined to guarantee quality continued their processes in the most critical industries such as energy generation, aeronautics and nuclear, until 1987 that the Guide for Quality Assurance in Great Britain BS 5750, turns into ISO 9000 standard under the support of the International Standards Organization, entity that promotes standards for products and services.

Throughout the years, Quality Management through ISO 9000 spread from its original application in critical industrial processes to all kinds of companies including those that generate intellectual products such as Legal Firms; it goes from fast food companies to the ones we are going to analyze in these lines: construction companies.

Let’s see the difference between the industrial processes the standard was originally design for, and the processes of the industry we are dealing with.

Quality in Construction Industry

In an industrial process, production resources are well defined and with a marked permanence in time. We could simplify this by saying that in an industry, machines and workers operating them are quasi-stable resources in the production process. Their modification is slow and it’s conditioned by technological improvement. 

The products generated in this industry by the use of those machines, are well defined and last in time.

Production means and products elaborated remain in time. As a result, the production procedures are developed at the beginning of the production process and remain the same throughout the process being altered only by modifications due to equipment technological improvement and continuous improvement processes resulting from the application of ISO 9001 standard. Through the application of the norm productive process flaws are capitalized in pursuit of continuous product improvement.

In the case of construction industry these conditions of process and resources stability that make relatively simple the application of the conditions established in the standard, are not verified. This turns the correct application of the norms exceedingly difficult.

The singularities of construction industry are the following:

The product generated by the construction industry is always changing. 

Indeed, every work fulfilled – a building, a power plant, a transmission line, a dam – is different and has its own singularities.

  • The resources employed in the productive process are also changing. Indeed:
    • The professionals and technicians employed in these constructions change due to the fact that the companies develop works with different characteristics.
    • Moreover, even though when the staff is the same, the professionals have neither the same level of competence nor a thorough knowledge of the procedures to complete.
  • In many cases, works are done between professionals coming form the companies and their subcontractors who should work as a real team with the implied information and qualifications.
  • Even though a new construction is done with the same characteristics that the one before, construction teams are not usually the same.
  • Execution and control procedures differ from work to work. Even though construction assignments have specific realization procedures, the technical contract specifications are different.
  • Finally, quality management systems do not exist or barely exist in non-certified companies or consortiums and Joint Ventures of certified companies in which each company has their own management procedures.

So, the question is: How can we apply an established standard for permanent and qualified human resources, stable production means, defined procedures and always alike final products to an activity where everything changes?

ISO 9001 standard has chapters related to the general organization of the company and one chapter aimed specifically to the production process.

The chapters on general organization refer to the company’s indirect operations, i.e. those processes that are not specifically developed for any work.

This is the case of Human Resources, Purchases, Equipments, accounts departments among others.

But there is a department, the production one, which is regulated in chapter 7 of the standard and refers to planning, production and product control processes.

After having applied the concepts of quality management to many important public and private works inArgentina, we can state that the inconvenients mentioned above caused poor instrumentation of chapter 7 of the ISO 9001 Standard by most of the building companies inArgentina, including many of the big ones.

Now, how can we approach this matter?

I asked myself that question when YPF invited our company to bid for the Quality Management Audit for YPF’sCorporateBuildingin Puerto Madero. 

Induction of quality management system

Supplies and processes should be effectively controlled by the ones producing them. This is the basic principle to achieve good results.

We have two participants in the productive process, the Contractor and the Work Inspector.

When I say Contractor I refer to the one that produces something.

A good contractor is the one who knows how to do the job. When we perform activities of direction, inspection and contract management it’s a relief to audit a good contactor.

If the contractor doesn’t do its job with a proper control system, it doesn’t matter how good the inspection is; the work won’t turn out fine.

Control activities will not necessarily increase the cost of the work. Contractors know how to their jobs and have all the experience. Sometimes they just need to follow certain organized steps within a structured management system to achieve quality.

This is why, before the work begins -no matter the level of certification the company has- as directors, managers or work inspectors, we have to verify the quality management systems employed by the contractors and if they are not consistent, which the case most of the time, we should lead the contractor to implement a suitable quality management system.

We never try to substitute the contractor’s shortcomings with an intensive inspection work. On the contrary, we believe that they are the experts on “doing” and that they were the ones qualified to carry out that work. That’s why we should help them to provide a self-controlled service through the application of a quality management system under the guidelines of the Standard.

After that, as inspectors and auditors, we audit the management system verifying that the contractor is taking evidences of the systematic control done and we inspect by sampling the resulting products under those controlled procedures.

In the case of YPF’s corporate building we were only in charge of auditing the quality management system.

The subcontractors in this project are some of the most important companies in the Argentinean market. Some of them had an ISO 9001 certification and some hadn’t. But all of them had to be induced to complete or implement from scratch a quality management system.

The result was that once consolidated the use of the management system, some companies remained using it as internal procedures and others got certified ISO 9001 with that same foundation.

What to control

Buildings such as YPF’s corporate building present great complexity.

Architecture, structure and facilities have characteristics and dimensions that are not what an average professional is used to find in common buildings. For example, the cool water collectors for the air conditioner system are steel pipes ASTM A53 Gr B of 12’’ similar to the ones used in distilleries.

All the supplies used in the building’s construction are of unusual amount: wires, connectors, lamps, lights, and the like.

So, how can we make an efficient control of all these supplies and processes involved??

Quality’s purpose is to create a product that, as times goes by, can be operated and maintained within design conditions and that provides safety to goods and guarantees health to the users.

Our criteria was to divide products and processes in different degrees of criticality, giving a greater level of control to those that affect people’s health and building safety.

These supplies were qualified as critical.

Within this category the supplies included are high power isolating switches, fire sprinklers, among others and the processes included are, for example functioning test for elevators as trials for emergencies.

The requirement for supplies traceability in the ISO 9001 standard is left to the Customer’s request.

Tracing a supply is to identify its exact typology, manufacturing lot and exact location in the construction work.

In order to ensure the safety of the building and its users’ helath the management system established supply traceability as a requirement for critical supplies.

Focusing on the construction work 

As we’ve said before, the standard establishes management conditions for every sector within the company: Purchases, Human Resources, Warehouse, Planning, Production, etc.

In cases of Standard application to quality management in construction, as for consultants and engineers, the fundamental target must be focusing in our work management, i.e. focusing in the development of the quality management system in the following aspects:

  • Engineering Management
  • Supplies Management
  • Production Procedures Management
  • Precommissioning and Commissioning
  • Quality Records Final Issue

 The Quality Supervisor of the building company is in charge of the proved control procedures established for all these stages.

When we talk about “proved” it means that the controls done are registered in forms that might be audited by others, whether they be in paper or in digital form.

Let’s make a brief summary about the stages of the quality management system.

Engineering management

The basic idea of this kind of control is to establish procedures to ensure that the blueprints or documents used in the construction works correspond effectively with the last version approved.

It seems obvious. However, the complication is considerable in big works.

The parties involved are many: Client, Work Direction, Managers, Construction Company, Subcontractors, Engineering Departments, Purchases, and the like.

For this reason the following procedures, among others, must be implemented: 

  • Procedures of emission control and report

Procedures of control of the emission state and report of documents, in the jargon “engineering situation” 

  • Procedure of implementation in construction

Clear procedures of what can the Contractor do with the various possible reports of a document, to ensure that the construction is done with those documents validated for such purpose. 

  • Procedures of valid revision

If there is a modification in any of the blueprints for construction, there is a procedure that assures that the copies distributed among all the sectors are properly replaced.

This also includes the equipment tested in factory through protocols such as boards and cells. They have to be manufactured and tested according to the latest engineering version. In terms of boards, this is a rare case since they receive new loads as the work progresses.

It seems simple but it is not for complex works. 

Supplies management

  • Approval requirements

Approval requirements must be established for each supply.

Each supply must fulfill certain requirements such as resistance requirements, anticorrosive protection, linearity, thickness, material quality, dielectric insulation, etc. to be suitable for its incorporation to the building work. 

  • Procedures of inspection in-factory.

Definition of product, procedures of prototype test, shipment test, packing conditions and documentation for dispatch to work. 

  • Procedure of reception in work and internal dispatch

Procedures of reception including proved verification of all requirements, storage conditions, segregation or quarantine in case of non conformities, recording of lots for traceable supplies and internal dispatch procedures.

Production Procedures Management

In this case the procedures employed in construction and assembling of supplies are described.

This procedure implies to specify the contractual conditions to the Contractor’s methods and equipment. It also implies to establish proved self-control records that allow the supervisors, who are in charge of going through the construction or assembling, to note or register the control results.

In fact, this control is always done by the companies in charge of the work. So this is simply about the implementation of a control record to be systematically completed in the moment of realization, which in practice, turns out to be a marginal cost.

Precommissioning and Commissioning

Precommissioning defines the pre-operation test of every part of the installation.

For example, the verification of a pump set in motion in normal operation conditions. Usually, this operation is done by the manufacturer. However, the fact that the item can be set in motion and that it functions correctly doesn’t mean that it was verified to meet the target for which it was designed. 

Commissioning defines the set in motion of the installation, i.e. the verification of the design conditions of the item.

This type of verification is usually done in big engineering works such as dams, transmission lines, industrial and oil related works but, as far as I know, there is no precedent of its application in big buildings.

In many of our supervised works, the systematic application of these procedures lead us to discover, for example, that the level of real lighting verified doesn’t correspond to the one in the design, or that the flow of air of a VAV box was not the corresponding one, or that the engines of the anti-smoke blinds didn’t work because they were wrongly polarized affecting not only the performance of the entire air conditioning system but also the building’s safety. 

In YPF’sCorporateBuilding, all these proved tests were done through pre-operation and set in motion protocols.

These protocols were designed as any other engineering document and contained, among other details, the expected conditions of the equipment or facility and all the verified conditions from the tests.

Final Emission of Quality Records

Once the work and the management process are over, all the documents that provide evidence of it are ordered into labeled volumes, in paper or in digital form. This invaluable information is left to be used in subsequent operation and maintenance tasks during the building’s lifetime.

This information includes records of traceability concerning critical elements so that, in case of failure, the building’s operations manager can locate them and those belonging to the same manufacturing lot.

Certifier or Consultant Company?

When YPF invited our company to quote for this service, we had the opportunity to compete with quality certifier companies.

 What made them decide for us was the methodology proposed to solve the problem related to the building’s quality management.

This methodology is the one described in this article.

So, what’s the difference between a quality certifier company and an engineering consultant company when it comes to focusing on quality problems?

I can answer this question knowingly since I’m a consulting engineer and I’m trained as IRCA-ISO 9001 auditor.

The quality certifiers are trained to verify if every management procedure of the auditing company suits the guidelines indicated in the Standard’s latest review. That is to say, they audit processes, not products.

Deceptively you can see in the boxes of pharmaceutical products a seal of conformity to the ISO 9001 Standard. However, when a search in detail is done, it can be realized that the seal related to the “process” used to manufacture the carton box. In the best scenario what is certified is the production process of the drug but never the drug’s qualities.

When we -the consulting engineers- face quality audits on construction works, we must apply the concepts of the ISO 9001 Standard to achieve a final product that responds to the conditions for which it was designed, prioritizing and balancing design, safety, construction and operative matters as well as possibilities of fulfillment.

That engineering criteria is what separates and differentiates us from them, the quality certifiers.

The market of work direction and quality certifier companies

During the last 20 years, several certifier companies have settled down in our country in order to develop a market of quality management systems certification for companies.

First they dedicated to the automotive industries, then to the industrial companies that supply automotive companies, after that they went for industrial companies in general, then service companies, banks, insurance companies and finally construction ones.

When an ISO 9001 certificate is granted to a company, it means that all the procedures that the company uses to manage quality are within the guidelines given by the standard. It doesn’t mention anything about the functional aptitudes of the products or services generated by those companies.

Lately, several private and fundamentally public clients, blinded by the word quality but little informed of the function of quality certification companies, entrusted these companies with control assignments of engineering works, assignments specifically related to work management which is an undeniable responsibility of engineers.

In fact, the two latest power plants in construction were trusted to international certifier companies for which quality is only one part of work direction.

Professional scope and training.

Direction and management of an engineering work or even an architectural work of the magnitude of YPF’sCorporateBuilding, is a non-delegable responsibility of engineers and engineer consulting companies.

But, due to the development of control and management techniques, directing a complex work without education concerning project management, costs and work standards, quality management systems auditing, environmental auditing, safety and sustainability auditing is not possible today.

In view of the advancement of certification companies over the engineering market, thoughtful, coordinated and effective actions are imposed to defend our market. Moreover, universities should take actions such as fixing the new engineers’ curricula to properly prepare them in direction and inspection of works and in particular the new paradigm of quality in construction.

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YACYRETA HYDROELECTRIC POWER PLANT

 

WORKS FOR THE PROTECTION OF THE AGUAPEY STREAM

 

Introduction

 

Aguapey Stream Basin Protection is one of the main works for the finishing of Yacyreta Reservoir Project. This Project is fundamental since its completion will impede the flooding of vast territories of the Republic of Paraguay thought the elevation of the reservoir storage level to its definitive height of 83 m above sea level.

Main works consist of 64.5 km of land dams which begin in the left margin of the river in Rincon de Santa Maria, cross over the main branch where they reach a maximum height of 43 m. After covering part of Yacyreta Island, cross over Aña Cua branch, then continue through the right margin 25 km, finishing in Paraguay’s San Cosme and Damian cities.

Nearby Damian city is Aguapey Stream, tributary of Parana River, which discharges an average flow of 25 m3 / s over the reservoir at a level of approximately 78 meters.

The Elevation of the Reservoir to its definite storage level of 83 masl would flood Aguapey Stream Valley, generating a sub reservoir of over 450 km2 of which 360 km2 correspond to mainland and wetland, and the remaining 200 km2 corresponding to productive land.

To prevent this situation, Protection Works of Aguapey Stream have been developed consisting of a land dam in the stream mouth to avoid flooding when the reservoir in filled with more than the current storage level and, a drainage channel of 12.5 km long downstream which connects with the collection channel that exists in the dam’s bottom until it reaches the Aña Cua branch.

 

Aguapey II – Aguapey Stream Closure Dam

 

The second stage of the work consisted in the construction of Aguapey Dam with an approximate length of 4.3 km. reaching to a crest elevation over the asphalt pavement of 86.45 masl, the construction of an irrigation channel in the Paraguayan margin and the Closure of the Temporary Deviation and the Opening of Aguapey Deviation Channel simultaneously.

The original Dam Project included in the bidding documents consisted on a body of soil and a blanket towards the reservoir. The Dam contained two lower clay cofferdams in the stream channel bed that along with the blanket were works performed over 14 years ago. All the leaking control in the foundation relied on the blanket and wells of relief.

The Work consisted on the drainage of the sector between both cofferdams and the continuation of the Dam building works until it reaches a final profile of 86.45 masl.

Before the construction started, work direction had begun, by conducting a geological-geotechnical auscultation of the stream channel, the cofferdams and the blanket, in order to reassure that the emptying of the precinct was done in a safety manner.

This study was meant to contemplate the current state of the work that was going to be part of the final project, and the fact that the reservoir level was higher than the level expected when the dam was planned.

As a result, the conclusion was that the bottom of the stream presented significant soil heterogeneity with important permeable sand layers and that the blanket had low waterproofing capacity.

After calculations of thin matter in which filtrations and slopes stability were analyzed, the conclusion was that the central precinct couldn’t be emptied without risking   siphoning effect and cofferdams failure. Even though it was possible to empty the precinct up to a level of 76.50 masl, the work between both cofferdams should be done under a strap of approximately 4 m of water.

Since the blanket provided a poor water proving capability, flow lines were to be prolonged underneath the dam so as to decrease the gradients to acceptable levels.

During design adjustment, 3 constructive alternatives were analyzed to enlarge the flow lines underneath the cofferdams precinct:

  • A bentonite screen constructed underneath the cofferdam in Yacyreta side that goes up to the waterproof mantles
  • A waterproofing of the bottom of the central precinct between the cofferdams through the placement of a concrete layer poured under water
  • The waterproofing of the mentioned precinct through the collocation of a waterproof membrane under water. 

Comparative Studies were done taking into account constructive complexities, costs, work safety and construction time since there were contractual key dates related to the expected time for the elevation on the storage level of Yacyreta Reservoir.

From those studies, the last alternative resulted as the most convenient being the new dam project as indicated in the diagram below:

With the alternative defined, the constructive challenge was the correct placement of the waterproof membrane under a strap of approximately 4 m of water.

Giving the critical conditions of the Project, after having the bottom waterproofed and before the drainage of the precinct, this one had to be filled up with sufficient weight so as to prevent a siphoning effect and stability mentioned before. Filling the area with sand coming from the Parana River was the most viable solution.

The selected membrane was made up of Polyvinyl chloride of 1.2 mm. thick and a resistance of 15 Mpa according to ASTM 882.

The membranes were rolled in rolls of about 1.80 m. The panels were welded by heat with controlled temperature to achieve complete fusion of juxtaposed panels, forming a single piece of the size of the precinct to be fulfilled.

The joints were tested in perpendicular tension to the seam making sure that they possessed greater strength than the membrane itself.

Before the placement of the waterproof membrane, another geotextile membrane was spread on the bottom to protect the former of any tearing element that may be deposited in the bed of the stream.

Alter being welled, the membrane was rolled and placed over a pontoon withheld and mobilized by a hoisting engine for a controlled placement of it over the bottom of the stream.

Before the filling of the precinct it was necessary to counterbalance the membrane to avoid dislocation or movements.

For this reason geocells of 7.5 cm high, 1.1 mm thick of geotextile were employed as well as concrete slipped in a working platform on a maximum area of 1500 cm2 to transform them into counterweight articulated sheets. Afterwards, they were lifted with a rocker arm and collocated over the membrane with a crane.

The positioning and the correct placement of the membrane as well as the geocells were inspected underwater by divers from the Consulting Consortium.

Once the membrane had been counterweighted, the hydraulic filling of sand took place up to the level of the new project.

Alter the filling was done, the precinct was drained to the expected levels continuing in this way with the work in the traditional way.

The new design is stable even though if the membrane deteriorates or even if it disappears during the work. Something that is highly improbable.

The Dam Project is completed with the construction of an irrigation channel on the Paraguayan side with a volume of 600m3 of reinforced concrete.

Special Tasks had to be made for the coordination of the closure of the stream discharge over the reservoir and the simultaneous opening of Aguapey Channel.

Those tasks were performed under strict supervision and having developed an Operative Plan and a Plan for Contingencies on the handling of the plug cofferdams and the Channel gates that provide all the possible contingencies and other exceptional events that could appear while the Aguapey sub reservoir drainage was done.

 

The main data of the project is the following:

 

The Project Adjustment, Inspection, Contract Administration and Work Direction were in charge of the Joint Venture COINTEC-INCONPAR-GCM-ELEPAR-GEIPEX-GCA UTE under the denomination ENERYA Consortium.

 

 

 

 

 

 

 

 

 

YACYRETA HYDROELECTRIC POWER PLANT

WORKS FOR THE PROTECCION OF THE AGUAPEY STREAM

Introduction

 

The Protection of the Aguapey Stream Basin is one of the main works for the finishing of Yacyreta Reservoir Project. This Project is fundamental since its completion will impede the flooding of vast territories of the Republic of Paraguay thought the elevation of the reservoir storage level to its definitive height of 83 m above sea level.

Main works consist of 64.5 km of land dams which begin in the left margin of the river in Rincon de Santa Maria, cross over the main branch where they reach a maximum height of 43 m. After covering part of Yacyreta Island, cross over Aña Cua branch, then continue through the right margin 25 km, finishing in Paraguay’s San Cosme and Damian cities.

Nearby Damian city is Aguapey Stream, tributary of Parana River, which discharges an average flow of 25 m3 / s over the reservoir at a level of approximately 78 meters.

The Elevation of the Reservoir to its definite storage level of 83 masl would flood Aguapey Stream Valley, generating a sub reservoir of over 450 km2 of which 360 km2 correspond to mainland and wetland, and the remaining 200 km2 corresponding to productive land.

To prevent this situation, Protection Works of Aguapey Stream have been developed consisting of a land dam in the stream mouth to avoid flooding when the reservoir in filled with more than the current storage level and, a drainage channel of 12.5 km long downstream which connects with the collection channel that exists in the dam’s bottom until it reaches the Aña Cua branch.

In this article I will refer to Aguapey I – Aguapey Stream Discharge Channel

 

Aguapey I – Aguapey Stream Discharge Channel

 

The first stage of the construction consisted on a linking channel from Aguapey stream intake position to the station 12+500 in which a junction is made between this one and the channel at the bottom of the dam in order to derive water from the stream to the discharge area in the Aña Cua branch. Construction began in the second part of the year 2005.

The path of the trace was carried out mostly on clay soils, having to go through an important basalt mantle, sandstones and altered rocks between the stations 8+100 and 10+275.

The first excavations in these progressives allowed us to perceive the bedding state of rocky mantles, having as a consequence important alterations that required a demanding and heterogeneous slopes project to meet the safety of all personnel and equipment employed during the process of excavation and also to meet the channel’s medium and long term stability.

For this reason the degree of alteration, the jointing and the RQD of the rock mantle have been entirely analyzed and different sections have been designed to assure proper slope stability.

Due to the alteration of the rock mass, blasting methods were adjusted as regards positioning, separation, depth and drilling load to the effects of making blasting works more efficient.

Taking into account the deep alteration state of the rocks and sandstones present and giving prestige to the integrity of the work in its expected long lifetime, slopes that don’t require injected anchors as a means of support were decided.

 In some cases of deep alteration shotcrete protective paving was done.

Pure soil areas were found with a few little rock outcrops up to the station 8+000.

In almost every section clay soil was found and slopes and lines sections 3H: 1V were design.

In these sections, excavations were done with conventional high performance equipment through traditional methods and intensive dedication.

Slopes protection was done with medium rank rocks up to the berm, which is likely to get into contact with the water flow, and through a vegetable protection and stabilization drainages in superior areas that presented possibility of collapse.

Main data as regards dimensions:

Channel Length: 12.5 km.
Design Flood:   700 m3/ sec
Regular Excavation Volume: 8.640.079 m3
Rock Excavation Volume: 1.863.895 m3
Total Volume of the Excavation: 10.504.000 m3
Channel Maximum Depth:        39.0 m.
Channel Minimum Depth: 8.0 m.
Storage level of the Channel’s Sill: 69.00 masl.

 

The Channel is crossed by many different building works that completed the Project.

One of them is the crossing of the 5B Route in the station 9+400. This route had to be relocated and re-projected and its crossing required a viaduct to bridge the irregularities caused by the channel’s slopes. In the Interjection between the route and the channel a structure was built to control the flow of water.

The viaduct was design with premolded concrete beams that were mounted through the use of launching beams. The total concrete volume was 750 m3.

The central section contains the Channel’s Flow Control Structure, made of four big columns that hold three flat gates set on by hydraulic mechanisms.

These Gates will allow the realization of maintenance procedures downstream.

The Control Structure involved the realization of 2.230 m3 of concrete.

The Channel Crossings are completed by 3 bridges for animal transit and an irrigation bridge with a capacity of 108 m3 to irrigate arable land in Paraguay’s territory.

Aguapey Channel’s Works were successfully completed and in the original deadlines established in December 2007, except for the Irrigation Bridge. Its construction is to be decided by Yacyreta Binational Entity in a near future.

The Final Project, the Inspection, Contract Administration and the Building Work Direction were in charge of the Joint Venture COINTEC-INCONPAR-GCM-ELEPAR-GEIPEX-GCA UTE under the name of ENERYA Consortium.

COINTEC, from The Argentinean Engineering Consultants Chamber (Cámara Argentina de Consultores de Ingeniería) acted as the Argentinean leading company.

 

Yacyreta’s hydroelectric power plant generates an approximate storage level of 78.50 masl. The elevation of the final storage level to 83 masl will produce a substantial improvement on the power generated by the turbines that must be evacuated to the consumption centers through the interconnected system in 500 kV.  

One of the transmission lines collaborating with this matter is The Extra High Voltage Line 500 kV – Rincon de Santa Maria – Mercedes – Colonia Elia. This one begins near the hydroelectric power plant and goes from north to south of Corrientes and Entre Rios provinces until it reaches Colonia Elia. The Line covers 281 km in the North Stretch and 386 km. in the South Stretch covering a total of 667 km.

The power is transmitted through three phases R, S, and T. Each of them has a bundle of 4 cables. Cables are protected against lightings through two steel ground wires.

The wires are protected against lightings through steel wires, called “ground wires”, set over the three phases.

One of the wires contains a fiber optic in order to transmit data between the main transformer stations.

Taking into account a certain conductor length, when the transmission voltage is low the energy losses increase substantially in such a way that according to the power to be transmitted and the longitude, in our case it was necessary to employ a voltage of 500 kV to make the project feasible.

Each one of the 4 conductors of each bundle is a modified Peace River wire consisting of an internal plait of 7 steel threads (total 31.92 mm2) that provides resistance to the whole and a plait along the perimeter of 48 aluminum threads (364,63 mm2 total) that confer electric conduction capacity.

The conductor’s insulation is done through the surrounding air. For this reason, different structures were set throughout the route. These structures support the wire to certain distances so as to impede discharges and at the same time they make everything stable in normal conditions and with an adequate safety level in view of destructive effects.

The line layout is a succession of stretches forming a polygonal which was designed bearing in mind, not only the different hills and valleys, constructions or plantations in the way, but also the geotechnical and hydrological conditions found in the area.

The conductor bundles are linked to the towers through chains of retention and suspension insulators respectively which were tested in laboratories to check their mechanic aptitude and electric insulation.

Each stretch of the polygonal is supported by lattice steel suspension towers, that is to say they load predominantly in transverse way. And at the end of each section, lattice steel angular retention towers were placed. These ones support the loads of wires coming from adjacent sections, plus the climate conditions in any possible way.

The suspension towers designed are the ones with the most modern and economical design, i.e. Cross Rope Towers.

This type of suspension structure is formed by two lattice steel masts.

Each mast has a couple of guys that hold it through the sides towards the front and the back, and are linked through a Cross Rope wire. This wire is a transversal catenary to the direction of the line that holds three polymer insulators that sustain the wires.

The retention towers are similar to the suspension self-supported towers but sturdier.

All the towers were designed and their prototypes tested in the Test Station that the manufacturer had in Belo Horizonte, Brazil.

The foundations employed for the structures varied greatly according to different factors such as the characteristics of soils, the presence of water and the accessibility of the construction equipment into the area.

The foundations of the masts of Cross Rope towers were done with pre-molded direct foundations when their transportation was possible, direct foundations concreted in situ, large diameter piles from 0,60 to 1,20 m.

Guys’ foundations were resolved by AIA injected anchors ISCHEBECK type. They consisted in a pre perforation with a steel hollow bar of high resistance. The length varied with the characteristic of soils. After that, grout rich in cement was injected at high pressure to form a traction pile in order to guarantee the guy’s working load plus a safety rate.

After being injected, all the anchors were tested for rupture load.

The foundations of the self-supported towers were done directly in situ when the soil allowed it.

In some cases, depending on the type of soil, such towers were founded through concreted piles in situ or traditional pre moldered piles.

In other cases where the water level was high it was necessary to work with elevated porches, as in the case of Rio Miriñay Crossing, where the towers are lifted between 7,00 and 8,00 m above natural land level.

COINTEC from The Argentinean Chamber of Engineering Consulting (Cámara Argentina de Consultores de Ingeniería) was in charge of the executive design of this Extra High Voltage Transmission Line.

 

DESCRIPTION OF STAGES IN TRANSMISSION LINES DESIGN

 

After knowing the power to be transmitted and the distance to which it must be transported, an electric study of the line is carried out. From this one the transmission voltage, conductors disposition and conductor section are selected in a way that different electrical considerations are taking into account, such as minimizing losts. This calculation corresponds to Electric Engineering.

Like I’ve said, in the case of the line described above, the voltage is of 500.000 V, i.e. 500 kV which in electric jargon is called “extra high voltage”.

From voltage, conductors section and their spatial disposition definition, the civil-mechanical design of the line starts.

I will try to sum up and simplify the different stages of design in order to make my writing more comprehensible to those who are not familiarized with this kind of design. Even though lines’ design has many more steps in between, their absence will not change this writing’s conclusion.

We can summarize the steps as following: 

  • Definition of Climate Conditions

Projects climate conditions can be defined by previous studies, regulations or weather analysis.

In terms of climatology we have no CIRSOC since in our case what we analyze is the possibility that wind speed may be stronger in some parts of the line. For this reason, probabilities, different from those of the regulation already mentioned, are analyzed.

By means of a probabilistic analysis of severe storms registered in relation with the physical damage they cause in a determined amount of time along the area where the line is going to take place, different wind speeds and load conditions are defined. This data is the starting point for the designer.

  • Conductor mechanical calculations, structure load hypothesis and failure sequence.

Once defined the conductor section by electric design, the mechanical calculation corresponds to the definition of the conductors’ electric wiring voltages associated with every one of the climatic conditions. The calculation is done through the application of the equation of the catenary with special compatibility considerations between aluminum and steel, and special creep considerations due to the slow flow over time. These designs are similar in nature to those employed in bridges shrouds.

From the voltage verified in the conductors and the guard wires for each climatic state, diagrams of the loads that the wires transmit to the structures are obtained.

The loads go from the wires to the structures and the foundations with different failure sequence rates. For this reason, the most suitable failure mode to the design has to be selected before hand.

  • Structures Design

The towers’ geometric design is done followed by the mechanical-civil design.

For this kind of lines, the structures are made of steel lattices of galvanized steel angles with special quality bolts.

All the safety and protection distances used in the tower’s geometrical design depend on each country’s own regulations. Moreover, in some cases international regulations are taken into account such as IEC (International Electrotechnical Commission) or CICGRE (Great Electric Networks Committee).

Naturally, wire goes with the whole line. Appropriate and economic designs as well as a disposition of structures and foundations are what optimize the line’s costs.

Structure’s design evolved along the time in such a way that lighter and more economical structures are being made.

Self-supported towers designs evolved into guyed V structures and more recently into Cross Rope designs in order to minimize production and assembling costs.

The design and sizing is done taking into account second order theory and nonlinear behavior of the guys.

  • Structure prototypes tests

Designs are verified in real size prototypes that are tested in test stations until they collapse. The optimized design is verified when the failure of any element of the tower is produced before load steps going slightly beyond 100 % of the theoretical load of the design.

This process requires the structural designer’s fine expertise.

  • Topographic surveys

These plano-altimetric field surveys are the ones that describe the contour map in which the line is going to be placed.

These surveys are not so different from the ones done for roads.

  • Structures optimized distribution

Even though it’s difficult to explain it in such a few words, we could say that in order to accomplish an optimized distribution of structures, the towers have to be distributed along the area at minimum cost and with such a disposition so as not to exceed the loads admitted by its elements – conductors, insulator chains, towers, guys, anchor bars, foundations – and, at the same time, minimal distances between conductors and ground have to be verified whatever the conditions of wind and temperature are.

These structural and geometrical calculations are carried out by means of specific software. The most popular version is the PLS CADD of Power Line Systems of USA.

  • Soil Studies

Wherever a tower of 480. m and 550 m. is going to be placed; soil, water and electric resistivity studies are performed.

The characteristics of these studies are similar to those for other type of designs.

  • Foundations Design

These designs employ traditional methodology with some technological components of their own and with some operative constrains of this particular type of work, but they are framed in the traditional design of foundations.

  • Complementary Designs

There are other less complex parts of design that are not mention here in order so as not to fill this article with descriptions that doesn’t contribute to the conclusion of it.

 

 

 

 

 

 

 

 

 

OUR MANAGEMENT AS A FUNDAMENTAL TOOL FOR SUCCESSFUL PROJECTS

 

The increasing globalization trend makes private capital investors the engine for development, requiring their investments to be successful.

Globalization, an ever-growing private participation in the development of projects and the outsourcing way for cost effectiveness, represent a challenge to the entrepreneurial organization. 

Today private projects relate such companies as SERVICES PROVIDERS, TECHNOLOGY SUPPLIERS and the COMPANIES EXECUTING the PROJECTS.

Under such conditions, how is it then possible to obtain economic undertakings in time and with an assured quality?

COINTEC, based on its vast experience, processes reports carried out for each structuring of an undertaking, and the experienced application of the most modern software available, attains the implementation of effective Project Management techniques needed for a successful result.

The heterogeneity of the involved agents forces a particular analysis for each case by means of multidisciplinary tools such as:

 

  •       Processes Survey
  •       Analysis of Information Transfer Methods.
  •       Programming of Control Database in any language. Programming in Visual Basic, Access, etc.
  •       Planning and Programming using Critical Path.
  •       Design and Operation of Timing and Industrial Costs Control systems.
  •       In-factory and in-Work Site Quality Controls.
  •       Design and Operation of Information Capture and Transfer Systems for local networks and the Internet.
  •       Projects Web Pages. Programming in HTML, Java, etc.
  •       Creation of Hierarchical Managerial Reports. 

 

 

 

 

 

 

 

 

 

INDUSTRY

 

Ensenada Industrial Complex is one of the most important petrochemical industrial complexes in Argentina.

Its productive structure has numerous Processing Units. Their control was being done in Control Rooms distributed in the Plant’s heart.

Repsol YPF, as the current plant operator, on a permanent Risk Assessment decided to update the safety conditions within the plant, focusing control in a Bunkerized Control Room to achieve a proper and orderly shut down in case of high power explosions.

For this important project REPSOL YPF trusted COINTEC with field studies, the complementary basic design, the multidisciplinary general detail design, specially the anti-blast design, the preparation of the bidding documents and the assessment during the construction of this important Control Room design with the most modern transmission, control and remote data visualization technologies.

 

 

 

 

 

 

 

Zaragoza Clinic, of METRO Company (Mexico’s Collective Transportation System) was projected and put into service during the initial stage about 20 years ago; back then, these facilities managed to fulfil the needs of S.T.C. working population as in general medicine is concerned.

Due to the growth of METRO’s network, the service capacity was exceeded in spite of the modifications and extensions that had been done in past years. To provide a solution, a new policy for the construction of the adequacy and extension project of Zaragoza Clinic was implemented so as to fulfil effectively as well as in due course the existing demand.

COINTEC carried out the expansion’s constructive project, which implied to double the constructed area by adding a new building to the existing one while it was still fully operational.

The work included:

  • All the civil work of the new building, from foundations to finishing, carpentry and locksmith, including an underground cistern tank.
  • Hydraulic Installation and fire detection and extinction system assembly.
  • Sanitary and pluvial Installation assembly.
  • Electric Installation and ground system assembly.

 

 

 

 

 

During the 90s, Mexico’s FEDERAL COMISSION OF ELECTRICITY (COMISION FEDERAL DE ELECTRICIDAD) began an ambitious expansion plan of Mexico’s Interconnected System of Extra High Voltage in 400 kV.

In order to fulfill the plan, FCE called for bidding which caused an intensive participation of the most important national and international companies in the market.

Due to the demanding requirement for qualified services, COINTEC started to provide services to Mexico in 1991, creating later on COINTEC S.A of C.V. an Engineering and Consulting Society under Mexican legislation.

From that moment, COINTEC participated on several projects presented by the FCE providing different engineering services from preliminary bidding projects to executive projects.

The following are some of the most important projects of Extra High Voltage Transmission Lines and their Transformer Stations:

 

  • EHVL 400 kV – ACATLAN – TESISTAN – AGUASCALIENTES (Bidding Project).

 

  • EHVL 400 kV – LAMPAZOS – ESCOBEDO (Bidding Project for the winning company and Construction Project).

 

  • EHVL 400 kV – CARBON II – LAMPAZOS (Bidding Project and Partial Construction Project for the Winning Company).

 

  • L.A.T. 400 kV – HERCULES – RIO ESCONDIDO (Bidding Project for the Winning Company).

 

  • EHVL 220 kV / 115 kV – PAQUETE LOS MOCHIS (Bidding Project).

 

  • EHVL 400 kV – MAZATLAN – DURANGO (Bidding Project).

 

  • EHVL 230 kV – HUITES – PUEBLO NUEVO (Bidding Project for the Winning Company).

 

  • EHVL y SE – SAN LUIS – POTOSI – ATLACOMULCO (Bidding Project).

 

  • EHVL 400 kV / 230 kV – TULA – QUERETARO – SALAMANCA (Bidding Project).

 

  • EHVL 400 kV / 230 kV – LAZARO CARDENAS – DONATO GUERRA – SAN BERNABE (Bidding Project for the Winning Company and Construction Project).

 

  • EHVL 230 kV – ZIMAPAN – DAÑU (Bidding Project).

 

  • EHVL 400 kV / 230 kV – PAQUETE OAXACA (Bidding Project).

 

  • EHVL 400 kV / 115 kV – PAQUETE CHIAPAS (Bidding Project).

 

  • EHVL 400 kV / 230 kV / 115 kV – PAQUETE TORREON (Bidding Project).

 

  • EHVL 400 kV – TUXPAN – TEXCOCO (Construction Project).

 

Unilever Pond´s Plant is located in Civac city – Cuernavaca – México.

COINTEC did a full survey of the electric facilities of the plant, in electric substation nº 1, service and production area, as regards board disposition, strength distribution (tray and main conduits path) and unifilar diagrams.

COINTEC has also updated UNILEVER’s documentation with the information obtained from the surveys and with respect to changes done during plant shutdown.

COINTEC used these blueprints as a base for the second stage of the surveys, location of the missing boards, determination of conductor section and paths up to each section board in each area.

 

 

 

 

 

 

 

During the past few years SHELL CAPSA developed in Argentina an investment plan for the remodeling and expansion of its Destilleries in Buenos Aires.

COINTEC is one of the Engineering companies selected to collaborate with this plan, having developed in past years works from which we can mention:

 

  • Installation of Air Compressor K-5917 800HP

 

  • LPG Recovery Plant 

 

  • Installation of a System for SH2 burning in Torch

 

  • Precinct for Training on Fire Drills

 

  • Tanks and Lifting Elements Survey and Classification. Blueprints according to Installation.