J-1-1_Statement_of_Work_(A0001)_(TRACK).pdf

INTERNATIONAL NARCOTICS

& LAW ENFORCEMENT

COSTA RICA

STATEMENT OF WORK

PROVISION AND INSTALLATION OF

DEMOUNTABLE CONTAINERS CAMP

FOR THE AIR SURVEILLANCE POLICE

COTO 47, COSTA RICA

STATEMENT OF WORK Page 2 of 26

STATEMENT OF WORK

PROVISION AND INSTALLATION OF

DEMOUNTABLE CONTAINERS CAMP

FOR THE AIR SURVEILLANCE POLICE

COTO 47, COSTA RICA

BACKGROUND

The USA Embassy in San Jose, through the International Narcotics and Law Enforcement (INL) Affairs Office, is interested to cooperate with the Air Surveillance Police of Costa Rica in providing and installing a mobile base camp to be located at the aircraft track in Coto 47.

The overall intent of the contractual effort for this project is to provide a base camp for the Police personnel that need to control the operations at the aircraft track. The base camp has to be constructed with containers in order to provide a provisional facilities that can be mobilized to other areas once it is no required.

The project shall be conducted in accordance with the plans and specifications detailed in this document.

The Contractor shall perform the following work:

C.1 SPECIFIC TASK

C.1.1 PRELIMINARY WORK

The preliminary work includes the conditioning of the area in order to install 3 containers for the mobile base camp. This work includes the following:

Demolition of the existing building and removal of the communication’s antenna that is located in the center of the plot (see drawing A-01). Also the contractor shall demolish the existing tree located in the back of the plot.

Develop the final designs of the access road, platform, and utilities and for the base camp (containers) based on the basic requirements detailed in drawings S-01, A-01, A-02 and A-03. The technical designs for the connection of utilities that include the electricity, sewage and water system shall accomplish with all the local requirements that the host country demands for construction approvals. Also the design shall include the concrete foundation for the containers.

Therefore the contractor shall provide all the qualified technical staff that will be responsible of all the designs, and will develop all the drawings according the local regulations based on the pre-designs, drawings and specifications stated in this document.

Construction of the access road from the landing track border to the container’s patio. The access road shall be constructed with 280kg/cm2 concrete reinforced with Ruredil XF-45 or other with similar or superior features. The access road shall be according to the site plan and the floor detail #2 addressed in drawing A-02. The contractor shall develop all the earthwork and backfilling in order to reach the respective floor’s levels and details. Also the contractor shall provide and install a drainage pipe of minimum 50cm in diameter across the road in order to avoid flooding and allow the evacuation of the rainy water through the natural course in the area.

Construction of one concrete platform for the Containers’ patio and the concrete foundations. The platform for the patio shall be constructed with 280kg/cm2 concrete reinforced with Ruredil XF- 45 or other with similar or superior feature. The platform shall be according to the site plan and the floor detail #1 addressed in drawing A-02. The contractor shall develop all the earthwork and backfilling in order to reach the respective floor’s levels and details.

Construction of the sewage system network that includes the provision and installation of one PVC Septic Tank (Ecotank type or other with similar or superior features) no less than 2500 liters

STATEMENT OF WORK Page 3 of 26 of capacity. The network shall include all the interconnection PVC pipes and 3 inspection boxes in which the sewage system for the containers shall be connected. The system will include a filtration field for final disposal for the septic tank; this area shall be constructed in the back of the plot.

In order to have the potable water required for the bathrooms and kitchen of the containers, the contractor shall build the respective network, that include the PVC pressure pipes, one PVC water tank of 2000 liters with a hydro-pneumatic system (pump of 1HP – 310 liters Compression tank).

The system shall be connected to the existing water system that is providing water to the existing building.

Regarding the electric connection the Contractor shall provide and install the main connection from the existing service to each one of the containers. This work shall be done according the local regulations and requirements of the host country.

C.1.2 PROVISION AND INSTALLATION OF CONTAINERS

The Contractor shall provide and install 3 Containers at Coto 47 according to the pre-design established in drawings A-01, A-02 and A-03 and also to the specification C.3.6 detailed in this document. The following containers are part of the project that the Contractor has to deliver in order to be used as soon the project is finished and according to the contract:

Container #1: One 40’ (2 TEU) Container that includes two dormitories for 4 policemen each, and two bathrooms.

Container #2: One 40’ (2 TEU) Container that includes one office for two work stations, one dining-room for 10 policemen and one kitchen.

Container #3: One 20’ (1 TEU) Container that includes two dormitories for 4 policewomen, and one bathrooms.

The Containers’ finishing shall be according the specifications detailed in this document (see specification C.3.6).

C.1.3 CONTAINERS’ FURNITURE AND EQUIPMENT

All the furniture and equipment detailed in drawing A-03 and in this document shall be provided and installed by the Contractor. The furniture and equipment shall be fixed to the containers (except for the chairs) in order to guaranty the transportation, for this purpose the contractor shall design elements that provide the fixation and facilitate the removal of the items for the respective maintenance.

C.2 GENERAL SPECIFICATIONS

All work shall be carried out in strict compliance with all contract clauses and these technical specifications. In the event that the Contractor discovers discrepancies contained in the various design/technical documents, Contractor must immediately notify the Contracting Officer Representative (COR) before taking any other action.

C.2.1 TRIALS AND TESTS

Materials, permanent equipment, its accessories and other elements destined to the work, shall be subject to trials and tests necessary to verify their compliance with specifications, properties and characteristics, in accordance with permitted requirements and tolerances, in line with the use for which they have been intended. Materials, equipment, accessories or elements that have not been accepted by the COR, shall be withdrawn from the work site or replaced, at Contractor’s cost.

Laboratory tests can be carried out, according to the specific case, at the work site or in laboratories previously authorized by the COR. Materials that bear quality certificates issued by International Standard Organization (ISO) or its equivalent, do not need to be routinely tested. Costs of laboratory trials and tests

STATEMENT OF WORK Page 4 of 26 shall be for the account of Contractor. The COR shall be able to carry out special trials and tests at any time if it is needed to clarify the quality of any item.

C.2.2 WORK EXECUTION

The different items of the construction program shall be carried out in a gradual and progressive manner, without initiating work that could later be affected by other items that have not been concluded or that lack an adequate support or safety, taking care that work that has been finished is not affected by weather or other elements.

Contractor shall be responsible for maintaining quality of work by following proper operation procedures in construction.

Throughout the different stages of construction work, Contractor shall obtain approval, either from the COR, in order to continue with subsequent stages of construction. Before receiving approval to continue through various stages of work, samples of completed work shall be tested to verify the quality of the work.

C.2.3 COST OF THE PROJECT

The Contractor should include all the costs of the materials, labor, transportation, and materials testing that will be needed to complete the project and comply with all the specifications stated in this document.

C.3 SPECIFICATIONS FOR MATERIALS & CONSTRUCTION ACTIVITIES

C.3.1 LAYING OUT AND LEVELING

Prior to initiating construction, the Contractor and COR will define the outline of the components of the project in accordance with the project drawings and, if necessary, the construction levels to be achieved will be appointed.

Additionally, signals (bench mark or B. M.) shall be placed on the main points to confirm location and levels of work. The signals shall be with paint at strategic points at the existing walls.

Before beginning the project, the Contractor shall verify all data, as shown in the drawings, and correct them in case there are any divergences between the real dimensions of the building and the data of the drawings, in accordance with the COR.

The construction axes and levels shall be marked in the building in a safe manner. The marks should be the most precise, clear, safe and stable for the most important axes and elements.

To comply with these requirements, the Contractor shall provide an expert topographer, supported by precision equipment such as: total station, levels, measuring tape, etc. as required for the placement of milestones and layouts of the remodeling project.

C.3.2 WARNING SIGNALS:

The Contractor shall provide all the necessary signs and announcements to prevent accidents according to the safety plan (that include signals for restricted areas, excavation zones, electric risk, flammable materials, construction zone, danger for general risk) which shall have the approval of the COR. Signs shall be made of acrylic or galvanized sheets painted with a yellow background and with red or black letters.

STATEMENT OF WORK Page 5 of 26

C.3.3 TEMPORARY STRUCTURES: SANITARY FACILITIES & WAREHOUSES

Temporary structures will be implemented in the plot for the Contractor’s personnel, workers. It is the Contractor’s responsibility to implement offices, warehouses, provisional bathrooms and the guardhouses required for their own use.

The Contractor will implement provisional sanitary facilities for the personnel, and a guardhouse with a temporary connection to a potable water and sewage system prior to commencing construction. One (1) sanitary facility shall be implemented for every 10 workers. The Contractor will be responsible for cleaning and maintaining these structures.

The materials to be used for these provisional facilities can be of metal, concrete, or wood, as long as they are secure and provide a private area. Also the Contractor is allowed to rent a place nearby the location of the project. The COR can demand changes or improvement of the provisional facilities at any time if he determines that the Contractor is not providing a clean area with sufficient privacy and safety.

C.3.4 EARTHWORK, EXCAVATION AND BACKFILLING

The work described in this chapter includes excavation and backfilling, as well as carrying, piling up and removing excavation material necessary for the construction of the building, channels, piping, and all elements indicated in the project drawings.

C.3.4.1 LEVELING AND CLEARING OF LAND

This section refers to land modifications required for the execution of building construction in accordance with the project drawings.

To determine final levels, theodolites or precision instruments will be used. If there are considerable differences with the specifications in the drawings, the COR shall be notified and only through a report of mutual agreement will the new levels be determined.

The residual material must be removed and placed outside the construction site in places approved by the local authority.

C.3.4.2 SLOPE CONFIGURATION

For the access road the contractor shall perform an slope configuration (slope of 45°) in both sides of the road in order to reach the level recommended in the pre-design. This portion of the contract will be carried out by hand. It consists of giving the slope a slant recommended to avoid sliding of material or soil. The purpose is also to provide appropriate precipitation drainage, including for very heavy rainfall.

Once excavation is finished and approved, resulting levels shall be verified to establish the need for complementary manual work for slope configuration. Location of final slants and levels shall be done to reach finished surfaces, in accordance with the final designs provided by the Contractor. Material which is wobbly, cracked, or in danger of sliding shall be removed by the Contractor.

The intersection area of the excavated slope and the natural land surface will be rounded off if required by the project. This activity, as well as material removal, is part of the slope configuration portion of the contract.

Disposal of excavation material will be done in places allowed by the beneficiary and or the local Municipality.

C.3.4.3 EXCAVATION

STATEMENT OF WORK Page 6 of 26

Generally, excavation is understood as the removal of volumes of land or other materials for the purpose of forming spaces for construction, foundations, structures, buildings, roads, etc.

Excavation shall be done according to the heights, limits, elevations, gradients and sections set forth in the contractor’s structural, architectural, and sanitary drawings, save for different or real conditions of the project.

During excavation, material satisfactory for backfilling shall be stockpiled in an orderly manner at a distance from banks of the trench equal to ½ the depth of the excavation, but in no instance closer than 60

cm. Excavated material not required or not satisfactory for backfill shall be removed from the site, without affecting the adjacent properties.

The material produced from excavation will be temporarily disposed of on the sides of excavations, so that it will not impede the execution of other work.

The final excavation is to be performed in the places where specific concrete, exterior works are to be built.

Excavation shall be carried out as close to the pouring of concrete to avoid any alterations due to bad weather.

In no case shall excavation be performed to a depth wherein the base soil is loosened or removed. If this happens, it will be considered as an “over excavation” that should be corrected by the contractor, according to the project specifications.

If, in the Contractor’s or COR’s opinion, the bottom of the ditch is not strong or is unstable, over-excavation (for additional information, see Section C.3.4.4 Over Excavation) will be carried out until solid ground is reached, otherwise another solution shall be jointly agreed upon by the Contractor and the COR.

It is the Contractor’s duty to protect the stability of the adjacent properties while excavation is carried out.

This should be done in such a way as to guarantee the stability of those buildings without causing any damage.

Excavation shall be protected against rain, landslides and other excavation. The Contractor shall protect the personnel executing the excavation in ditches and, if for safety reasons it is deemed necessary, the Contractor shall provide timbering and shoring.

The shoring shall be reviewed and approved by the COR, and the Contractor will protect the shoring and will removed shoring after the excavation has been performed.

The standards for the provisional shoring in excavations are as follows:

When assemblages and props are used, they are placed at intervals no greater than 2.50 meters, measuring the timber lengthwise, and should penetrate the land enough to withstand the push of the walls in the excavation.

Metallic cribbing shall be used for excavations greater than 5.00 meters deep or when the lateral push on the excavation walls is great.

Whenever the conditions of the land demand so, or when the structural drawings states, the excavation walls will be protected with stakes or projected concrete. This will be subsequently refilled according to the requirements established for the filling process.

For piping placement in excavation, the filling will be laid as a first step to cover a height of at least 20 centimeters above the highest part of piping and shall be compressed in accordance with the article of this section. Excavation will be done from the ditch in accordance with the gradient slope and required transversal lines for placement of piping as indicated on working drawings.

C.3.4.4 OVER EXCAVATION

STATEMENT OF WORK Page 7 of 26

The term over-excavation, for the purposes of this contract, is understood as excavation outside the lines and levels set forth in the drawings, the specifications and/or the COR’s instructions.

If over-excavation occurs, removal should go up to the required level, and filled with soil, granular material or concrete or any other material approved by the COR. Compressing will be done with adequate water content, in layers that will not exceed a thickness of 15 cm, using an appropriate mechanical compressor.

The compression process shall be done according to the regulations established by the standards of the American Association of State Highway and Transportation Officials (AASHTO T-130).The material to be used shall be granular selected material according AASHTO 145.

The Contractor shall not receive any additional payment for over-excavation that may result from the conditions of the land, the action of natural agents, operations that are executed to facilitate the construction, and mistakes made by the Contractor.

C.3.4.5 EXCAVATION IN CONGLOMERATE STRATUMS AND ROCK

The process of excavation when hard materials are found which cannot be loosened through ordinary methods is understood as conglomerate and rock excavation. For this process, the use of shovels, pickaxes, backhoes, or excavators is not sufficient and explosives, mechanical hammers, wedges, or sledge hammers or other similar are absolutely necessary.

If a rock is found in pieces, only fragments greater than 200 cubic decimeters will be considered a rock.

When removing rock or masonry fragments from a ditch is necessary, and if they form clusters that do not have to be totally extracted in order to erect structures, those pieces excavated within the presumed boundaries will be considered as rock, although their volume could be smaller than the one indicated in the above paragraph.

If the bottom of the trench (made to install pipe lines) is made up of conglomerate or rock, excavation will be carried out up to 0.15 m below the seat of the pipe and it will be filled later with sand and fine gravel.

When excavation is carried out on fixed rocks, the use of explosives will be allowed, provided that the Contractor does not alter the land adjacent to the excavation works, and has received prior written authorization from the COR.

C.3.4.6 EXCAVATION WITH WATER PRESENCE

The presence of water may be caused by water coming from the underground, rainwater, floods, operation of the construction, sewage, etc.

Excavation cannot be executed in the presence of water, whatever its origin. For this reason, due precautions and protections must be taken, as construction techniques advise in these cases. Excavating during the rainy season is prohibited.

When placing stone masonries and/or any structure (e.g. concrete structures), the Contractor will insure that water is not present in excavations, and that it will remain so until mortar and concrete have set.

The presence of water makes work more difficult and the safety of personnel and the overall project is jeopardized. Therefore, the Contractor is required to take due precautions to eliminate water in excavation sites by using stake boards, cofferdams, pumping, drainage, curbs, etc.

Again, excavation is forbidden during the rainy season. None of the excavations shall have water present before placing the pipes, and under no circumstance will they be placed under water. The trenches shall remain dry until the pipes have been totally coupled and the welded junctions are completely dry.

STATEMENT OF WORK Page 8 of 26

C.3.4.7 EXCAVATION FOR FOUNDATIONS

This section refers to the depth of the excavation needed for foundations that will be lower than that marked for cleaning and leveling, down to the depth established by the structural drawings or by recommendation of COR. Excavation shall be done in manner best suited for the construction, based on the structural designs that will follow. The excavation sides will be totally vertical and the bottom will be clean, free of waste, and correctly leveled.

In no case will machine excavation be performed to a depth in which the soil of the bottom is loosened or removed. The final material to be excavated must be removed by pickax and shovel to a depth of 50 centimeters, also known as “conforming the plinth or ditch bottom.”

If landslides or collapses due to the depth of excavations or inconsistency of soil happen, shoring shall be built to prevent further damages or accidents.

Ditches shall remain clean and no work will be executed in them if waste, loose dirt, water, etc. are found.

After casting the foundation and pouring the foundation, the gap caused by excavation shall be filled and compressed with the extracted soil until reaching the initial level. This work shall meet the specifications detailed for “compacted backfilling with natural soil” (see Section C.3.4.9.1 Compacted Backfilling with Natural Soil). Leftover material shall be removed or placed as filling if acceptable by COR.

The Contractor shall take all necessary precautions to prevent water from entering excavation sites awaiting concrete pours. However, if soil deterioration is caused by unforeseen circumstances, the Contractor will perform necessary studies and analyses of the soil to deepen excavation.

C.3.4.8 REMOVAL OF WASTE AND/OR EXCAVATED MATERIAL

Waste removal is defined as the method of transportation of the materials produced by excavation, which should have a specifically determined place for disposal approved by the local authority.

When there is an excess material, the Contractor shall remove it and place it outside the area of construction, where such material will not obstruct watercourses or cause detriment to the neighboring areas.

Excess or waste material shall not be located in properties adjacent to the construction site unless the Contractor receives written authorization from the owners of such properties, evidence of which shall be provided to the COR upon request.

The material produced by excavation that will not be used for the construction of the project shall be removed from the site using heavy mechanical equipment in good condition, without causing vehicle transit interruption or neighbors’ annoyance.

C.3.4.9 BACKFILLING

Backfilling is defined at the sections indicated by the project, the existing gaps between structures and excavations, or between the structures and the natural soil in such a way that any point of the finished section will remain at a distance greater than 10 centimeters from the corresponding section of the project.

The backfilling process will be carried out using earth, gravel, sand or rock with approval from the COR.

Prior to backfilling, the land shall be free of debris, trunks, branches, etc., and in general of all organic material and all the material that is not appropriate for backfilling. The COR will approve the material that will be used for backfilling in advance and the material will come from the excavation itself or other extraction sites.

STATEMENT OF WORK Page 9 of 26

The backfilling will be done according to the project specifications and according to the lines, levels and gradients described in the architectonic and structural drawings.

The Contractor is required to obtain, transport and maintain the necessary material for backfilling, either from the excavation site or from qualified quarries.

Special care will be given by not using the mechanical compactor in areas close to buildings or existing construction inside or outside of the property. If any damage occurs, this shall be repaired and costs assumed by the Contractor.

The refill and/or cover of any excavation that contains lines or pipes installations and other services will not proceed until they have been placed and tested as well as approved and accepted by the COR.

The backfilling for subflooring will be placed and mechanically compacted in beds of 0.20m thick according to the D698-64Tspecifications of the American Society for testing and Materials (ASTM).

Backfilling with gravel, sand or ground stone for formation of drains or filters shall be consistent with the grain grading specified in the working drawings; materials will be sieved and washed if required. For filter formation, the materials will be placed in such a way that the higher grade particles remain in contact with the structure and the ones with lesser diameters in contact with the natural terrain, unless otherwise indicated.

The backfilling of rock placement shall be made with fragments of healthy, dense, and exposure-resistant rocks, with angle formation satisfactory to COR. The minimal size of the stones shall be 20 centimeters, and the maximum determined by the project, always protecting the structure.

C.3.4.9.1 COMPACTED BACKFILLING WITH NATURAL SOIL

Compacted backfilling with natural soil is defined as placing horizontal layers of the existing soil, with a thickness of 20 cm, with the humidity that the material requires to get a mechanical compression to 95% minimum of the density of the Proctor Standard measure. Each layer shall be evenly compacted on the entire surface by pneumatic rammers or other construction equipment until obtaining the maximum compression possible with the use of these tools. The material to be used in this backfilling shall be free of organic residues and waste. Prior to backfilling, the land shall be free of debris. The COR will approve in advance the material that will be used in the backfilling process. The compression process shall be done according to the standards of the American Association of State Highway and Transportation Officials

(AASHTO T-130).

If the approved material for this backfilling is not enough to reach the levels specified in the project design, the Contractor shall complete the volume needed, with granular material according to the specification for “Compacted backfilling with granular material.”

The Contractor shall carry out laboratory tests to guarantee the compliance with the aforementioned specifications and the cost of these tests will be assumed by the Contractor.

C.3.4.9.2 COMPACTED BACKFILLING WITH GRANULAR MATERIAL

Compacted backfilling with granular material is defined as placing horizontal layers of sub-base to a thickness of 20 cm. Each layer will be compacted evenly on its entire surface by pneumatic rammers or heavy construction equipment until obtaining the maximum compression possible with the use of these tools. Compaction shall be carried out using sheepsfoot rollers, pneumatic-tried rollers, steel-wheeled rollers, vibratory compactors, or other approved equipment. The thickness of the backfilling shall be in accordance with the structural and architectonic detailed drawings. Prior to backfilling, the land shall be free of debris. The COR will approve in advance the material that will be used in the backfilling process.

STATEMENT OF WORK Page 10 of 26

The compression process shall be done according to the standards of the American Association of State Highway and Transportation Officials (AASHTO). Compacting shall be have a 95% of the maximum density (Proctor Test). The material to be used shall be granular selected material according AASHTO 145 (A1, A2, A3).

C.3.5 CONCRETE STRUCTURES

C.3.5.1 MATERIALS FOR CONCRETE

C.3.5.1.1 Cement

Cement is any powder-like material that mixed with a liquid, forms a binding paste capable of hardening, in time, both under water as well as in free air and which serves to join solid bodies. It must comply with the ASTM standards, specification C 150.

The Contractor shall provide adequate facilities for the storage and protection of the cement against humidity. Cement that for any reason is partially dried or has clods is unacceptable. The Contractor will not use rejected cement or previously used bags of cement.

Portland Standard cement of national production will be used and should comply with ASTM specifications and be accepted by the corresponding entities. The use of foreign cements is acceptable in case national cement is unavailable, as long as these foreign cements comply with the same basic requirements. All cement shall comply with the regulation RTCR 383:2004 (“Reglamento Técnico de Costa Rica”). The use of different brands of cements is not recommended at all when building one single structure or foundation.

The manufacturer might decide to add additives during the cement manufacturing process, which is acceptable if those materials, in the amounts to be used, meet the requirements of ASTM standards.

The cement must be stored in a completely dry and ventilated place, under cover, and placed on wood pallets. No more than 14 bags of cement should be placed on top of each other and the cement should not be stored for long periods of time.

If Portland cement has been stored in bulk for over 6 months, or has been stored in bags for over 3 months, the cement should be sampled, tested and must meet the appropriate requirements, before being used.

Cement shall meet the tests listed in the previous paragraph, and correspond to ASTM and AASHTO standards:

TYPE OF TEST

Chemical analysis Grain fineness Setting time Normal consistency Resistance to compression Resistance to flexion Resistance to pulling forces

If the test results do not fulfill specified requirements, the cement will be rejected.

If there are several types of cement, these should be stored separately and correctly identified so that they are not mixed.

C.3.5.1.2 Gravel Stone Aggregates

STATEMENT OF WORK Page 11 of 26

Gravel stone aggregates for concrete will be made up of gravel, crushed rocks, or a combination of these, and shall meet the requirements of the American Concrete Institute ACI, AASHTO and ASTM standards.

Concrete will use mechanically ground rocks, from andesitic sources, preferably made out of blue rocks.

Gravel stones used for the manufacturing of any type of concrete shall be the product of mechanical grinding; the use of natural material extracted from a quarry is not allowed. This material shall preferably be blue stone and shall have passed through a 4 cm sieve, as specified in the ASTM standard.

The Contractor shall assure availability on the work site of the required quantity of gravel stone that will be used for mixing concrete, fills, filters, transition zones, drains, etc.

The Contractor shall use gravel without impurities, organic matter and other harmful elements. It shall be thoroughly washed before use. Tile-shaped or long- shaped gravel is not allowed.

The thick aggregate that shall be used for concrete elaboration will consist of hard rock fragments with a diameter not less than 5 millimeters, dense and long-lasting, free of objectionable quantities of dust, soil, slates, alkalis, organic material, vegetable soil, mica and other harmful substances.

Round-shaped gravel that has been manually crushed or gravel from natural quarries, as long as it has a cubic or pyramidal shape, may be used. Gravel with over 15% of flat or long-shaped rocks will not be used.

The production and storage of gravel shall be done by dividing the gravel into three separate groups according to the maximum nominal size of the gravel and the following requirements:

SIEVE PERCENTAGE OF MASS PASSING SAUARE MESH SIEVES

(square openings) No.4 to 3/4"(19 mm) 3/4" to 11/2"(38mm) 11/2 to 2" (76mm) 3" (76 mm) 90-100 2" (50 mm) 100 20- 55 11/2" (38 mm) 90-100 0- 10 1" (25 mm) 100 20- 45 0- 5 3/4(19mm) 90-100 0- 10 3/8(10mm) 30- 55 0- 5 No. 4(4.8mm) 0- 5

All components added to Portland cement concrete shall meet the requirements regarding particle size standards according to ASTM C136-06 and to the regulations of INTECO (Instituto de Normas Técnicas de Costa Rica).

The ASTM standard requires particle sizing tests to verify their sizes. This will also be confirmed by the Contractor.

The specific gravity of particles shall be determined according to the testing method specified by the ASTM standard.

The following are the maximum allowable percentages (expressed as percentages of the sample weight) of foreign substances and determining factors of added components.

COARSELY-GRAINED COMPONENTS % OF THE TOTAL WEIGHT

Firmness, sodium sulphate, losses after five cycles: 12.00 Abrasion – Los Angeles test (losses): 35.00 Material that passes through sieve number 200: 0.50

STATEMENT OF WORK Page 12 of 26

Clay: 0.25 Coal and lignite: 0.25 Soft or lightweight particles: 2.00 Other substances: 1.00

The amount of harmful substances in gravel stone shall not exceed the limits specified by the ASTM standard for this component.

The use of premixed concrete produced by companies that have certificates proving the use of high-quality materials is recommended. Specifically, the company must support its decision to use certain materials based on their resistance, which cannot be lower than the one specified in the structural design.

C.3.5.1.3 Fine-Grained Sand

Fine-grained sand for concrete should be comprised of natural sand, sand from grinding processes (gravel), or a combination of both.

The sand should be clean, siliceous (quartz or granite sand), from mines or from other inert materials with similar characteristics. The sand should be made up of hard, angular and rough grains, which should be strong and free from soft particles, organic material, shale or slate. Clayish, soft or disintegrating sands must not be used. Likewise, finely-grained sand with a humidity of over 8% must not be used.

The requirements regarding particle sizing shall meet the INTECO and ASTM standard, i.e. arid elements for concrete. The fineness module shall be less than 2.4 and greater than 3.1. After the particle size has been established, the fineness of the sand module is to remain stable, with variations of at most ± 0.2. In the event the variation is outside of the defined range, the COR shall review to determine whether another combinations must be produced. If there are no satisfactory results, this material must be rejected.

The material shall meet the following tests:

The ASTM C136-06 standard specifies the particle sizing tests to be undertaken to verify their sizes.

The specific gravity of sand particles will be determined according to the testing method specified by the ASTM standard.

The weight per unit of sand particles will be determined according to the testing method specified by the ASTM standards for concrete.

The fine-grained arid component must not contain harmful or organic matter. To verify this, the testing method specified by the ASTM standard shall be used. If it is darker than the standard, it must be rejected.

Fine-grained sand that was rejected due to organic impurities can still be used if the discoloring is mainly caused by small amounts of coal, lignite, or similar discrete particles. It may also be accepted if, after running tests to determine the effect of organic impurities on the resistance of concrete, the relative resistance, after a seven-day period, according to the ASTM standard, is not lower than 95%.

Fine-grained sand to be used in concrete that will be exposed to water, to prolonged exposure to environmental humidity, or contact with soil humidity, should not have materials that might react adversely to the alkali of cement and whose amounts are such that an excessive expansion of concrete might take place. If these materials are present in harmful amounts, fine-grain sand can be used, provided that the cement will have less than 0.6% alkali estimated based on the amount of sodium oxide.

Fine-grain sand submitted to 5 immersive and drying cycles for the test to measure the resistance to disintegration (the ASTM standard) must have a mass loss of less than 10% if sodium sulfate is used and less than 15% if magnesium sulfate is used. Finely-grained sand that does not meet these standards may be used provided that concrete with similar features, made from similar sand from the same source, has produced satisfactory results when exposed to similar weather conditions to the ones to which the concrete with those characteristics will be exposed.

STATEMENT OF WORK Page 13 of 26

All fine-grain sand used for tests shall meet the sampling requirements established by the ASTM standard.

The amount of harmful substances in fine-grain sand shall not exceed the limits specified by the ASTM standard.

The following are the maximum allowable percentages (expressed as percentages of the sample weight) of foreign substances and determining factors of added components.

FINELY GRAINED SAND % OF THE TOTAL WEIGHT

Material that passes through sieve number 200 3.00 Clays and disintegrating particles 0.50 Coal and lignite 0.25 Other harmful substances 2.00 Maximum allowable total 4.00

The amount of harmful substances in fine-grained sand shall not exceed the limits specified by norms ASTM standard and INTECO (Instituto de Normas Técnicas de Costa Rica) for fine-grained sand.

C.3.5.1.4 Large Stones for Cyclopean Concrete (Rip-Rap Concrete)

The large stone for cyclopean concrete shall come from quarries or collection banks that must be clean, granitoid or sandstone. Stones of between 10cm to 25cm in diameter shall be used for this type of concrete.

The stone shall not exceed more than 50% of the concrete component. The stone will be solid, resistant and long-lasting, and free of organic matter or clay residues. It will be homogeneous, with uniform color and will be free of cracking or crevices (clear sound to hammering), or other flaws that would reduce its strength.

Any weathered stone (affected by meteoric phenomena) must be rejected. It must have a density equal to or greater than 12% on durability assays.

The size of the stones shall not surpass 25% of the smallest dimension on the structure to be built. The Contractor shall note that humidity reduces the strength of concrete, and for this reason porous stone assays shall be done by a saturation process without localized efflorescence.

Upon request from the COR or Contracting Officer, the Contractor shall provide the results of tests and assays used to verify the good condition and quality of the aggregate, taking into consideration the norms specified by ASTM and INTECO for this particular case:

Coarse arid materials for concrete. Determines the abrasion value of the coarse arid material for particles greater than 19 mm, using the Angeles abrasion machine.

Arid materials for concrete. Determines strength to disintegration.

Transportation will be in bulk and precautionary measures will be taken so that during loading and unloading deterioration is not caused by touching one against the other. Covered storage is not necessary, but the Contractor must insure that the material will not become saturated with dust and other material that can lower its strength.

C.3.5.2 TYPES OF CONCRETE

This section addresses the necessary materials, equipment and labor to make plain concrete.

Concrete is the hardened product resulting from the mix of the Portland cement, water and stony aggregates in adequate proportions. It can contain additives to provide it with specific or special properties.

Cyclopean Concrete (Rip-rap):

STATEMENT OF WORK Page 14 of 26

Cyclopean concrete shall be constructed with a mixture of a 60% plain concrete and 40% large stones (variable size between 10 and 25 centimeters). The plain concrete to be used in this job shall have a minimum resistance of 180 kg/cm² on the 28th day, and the materials shall be saturated before creating the mixture. Stony materials will comply with the ASTM standard and dosage will be according to concrete design. In the first step, the Contractor shall apply a plain concrete layer of 15 centimeter depth and subsequently a layer of stone shall be placed manually on top. The spaces between the stones will not be less than 5 centimeters in any of the rows and from structure edges. The next step is to place another layer of plain concrete and the same procedure is followed until the desired height is reached. The dosage varies in accordance with the structure needs described in the respective drawings.

Plain Concrete:

Plain concrete results from mixing coarse, arid materials of up to 5 cm. in diameter (nominal) and fine, arid materials joined by a paste of water and cement (see specification under Section C.3.5.1 Grave Stone Aggregates, and “fine-grained sand” under Section C.3.5.1 Fine-Grained Sand).

To obtain good, uniform, strong, long-lasting and cheap concrete, the following items should be closely monitored:

Material quality Dosage of components Management, placing and concrete setting

The proportion of water and cement must be tested for appropriate dosage and should include the following data points:

Degree of humidity of aggregates Climate of the work area Use of additives Conditions for concrete exposure; and Thickness and type of planking

The dosage of plain concrete varies in accordance with the type of work that it’s going to be used on:

DOSAGE STRENGTH (Kg/cm²) USE

1 : 3 : 6 180 Concrete thick walls of larger thickness, pavements, first concrete layers, floors and anchors for pipes.

1 : 2 : 4 210 Non-voluminous walls and jobs of reinforced concrete in general. (retaining walls)

1 : 1,5 : 4 280 Hydraulic jobs in general

Another factor that has influence in concrete design and its final quality is the water-cement ratio, which has to be as low as possible. This will ensure that concrete always has the conditions of impermeability, and allows for handling and workability in accordance with each purpose.

In order to obtain the appropriate concrete resistance the Contractor shall be consider at the concrete design process, the quality of the materials and the conditions for the curing procedures in order to ensure a low water cement ratio.

STRONG TO:

CONCRETE WITHOUT AIR

INCORPORATOR

CONCRETE WITH AIR

INCORPORATOR

THE SPECIFIED

COMPRESSION

f'c (Kg/cm²)

ABSOLUTE

RELATION BY

WEIGHT

LITERS PER

BAG OF

CEMENT

ABSOLUTE

RELATION BY

WEIGHT

LITERS PER

BAG OF

CEMENT

STATEMENT OF WORK Page 15 of 26

175 0,65 32,40 0,54 37,00 210 0,58 29,30 0,46 23,00 245 0,51 25,70 0,40 20,00 280 0,44 22,20 0,35 17,70 315 0,38 19,10 0,30 15,10 350 0,31 15,10 ** **

Strength at 28th day for the cement to meet the strength limits of the ASTM regulations norm, Type I, IA, II or IIA; and strength at 7 days for cements Type III o IIIA.

With the majority of the materials, the given water-cement ratio, provides average strength higher than the indicated.

** The concrete mix dosage for strength greater than 300 Kg/cm² with air incorporator.

The concrete shall be mix by mechanical vibration, except for small amounts (less that 100 kg) that can be mixed by hand. The dosage will be made by weight, using a platform scale that allows putting a wheelbarrow of aggregate on it.

The concrete prepared in a mechanical vibration will be mixed at least for the time indicated in the following table:

CAPACITY OF THE CONCRETE

MIXER

m3

MIXING TIME

Min

0 – 1.50 1.5

1.50 – 2.30 2

2.30 – 3.00 2.5

3.00 – 3.80 3.75

3.80 – 4.00 4.75

The machine will give at least 60 revolutions in the indicated times.

Concrete will be discharged completely before the mixer will be loaded again. The mixer will have to be cleaned up at regular intervals while being used and will have good mechanical maintenance.

When the concrete is mixed by hand; the sand and the cement will be mixed in a dry basis until it gets a uniform color. The rubble or split stone will be extended in a platform of wood or metal forming a layer of uniform width; adding humidity and then adding the dry mortar. The mix will be mixed with shovel, until it becomes completely homogeneous.

Under normal conditions of operation, the changes in the consistence as indicated in the settlement test will be used as indicators of change in the characteristics of the materials, the ratios or the water content. To avoid mixes too dense or too fluid, the settlement tests shall follow the following guidelines stated in the chart below:

TYPE OF CONSTRUCTION

SLUMP (mm)

MAXIMUM MINIMUM

Concrete foundations, walls and plinths 127 50 Plinths without framework, melting boxes and walls over structures.

100 25

Slab stones, beams and concrete walls 152 76 Pillars for buildings 152 76 Pavements 76 50 Construction of heavy masses 76 25

The setting tests will be done before the placement of concrete additives.

STATEMENT OF WORK Page 16 of 26

When concrete does not reach the strength for compression (cracking load) for which it was designed within 28 days it will be necessary to improve the quality of the aggregates or to create a new design in a material strength test lab.

Test for concrete:

Consistence tests will be made in the first stops until the outflow conditions of the mix are stabilized. In case there are changes in the humidity conditions of the aggregates or weather changes, if the process of transportation from the cement mixer to the foundation site is too long, or is subject to considerable evaporation, field testing shall be performed. The tests will have to be done with the required frequency as follows:

The compression strength tests will be done based in the ASTM specifications for cylindrical molds. Two cylinders for each 30m3 of poured concrete will be taken at least, one that will be tested seven (7) days later and the other twenty eight (28)days. The results of the first test will be useful to analyze the job conditions, mix, materials, curing period and the relationship with the final strength to be achieved, with the objective of facilitating its control.

The result is valid when several tests and an average of the series of tested cylinders has been taken, which cannot be distorted or defective.

When the average of results of the cylinders is taken in a day, tested for seven days, and it does not meet 80% of the compressive strength, an additional drying period for a maximum lapse of 14 days will be ordered; additionally, structure tests will be required and shall be submitted to the COR.

In the event that tests show that that concrete does not meet the specified quality, the structure must be reinforced or replaced, either totally or partially, in accordance with the case, then the Contractor shall proceed to create a new design for the next structures.

Transportation and handling:

Concrete will be transported from the concrete mixer to the site, using methods that prevent or reduce to a minimum separation and material losses. The equipment shall be of an appropriate design and size to assure concrete flow at the delivery site.

Discharge trucks (mixer) will have to avoid the segregation of components. Their surface will have to be smooth (preferable metal) to avoid filtering and overflows.

Concrete will not be located at heights greater than one meter above the plank molding or foundation bottom, when required to drain the concrete from a major height; special devices to prevent segregation will be used.

C.3.5.3 ADDITIVES

Additives will be used on concrete to improve one or several of its qualities, as well as the following:

Improving workability Reducing material segregation Air incorporation Acceleration of the drying process Retard the drying process Waterproofing Thickening of concrete

STATEMENT OF WORK Page 17 of 26

In any case, the use of different additives will be done only with the prior written authorization of the COR, and observing the dosage recommendations from manufacturer. Additives for concrete shall be from recognized manufacturers that meet all the standards set for by ASTM and INTECO regulations for chemical additives and air reducing additives for concrete.

Water reducing, retarding, and accelerating additives must comply with the "Specifications for Chemical Additives for Concrete" (ASTM–C–490) and all other requirements described in it, except the infrared analysis.

C.3.5.4 FORMWORK

It will be understood as formworks the volumetric shapes which are made with pieces of wood, metal or any other resistant material, so as to support the emptying of concrete, in order to mold it to the foreseen shape.

The formworks generally built in wood, shall be sufficiently strong to resist the pressure, resulting from the emptying and vibration of concrete, to be rigidly supported in their correct position and sufficiently waterproof as to avoid the loss of slurry.

To build the different concrete sections, contractor shall use metallic or timber formworks according to the measures that are detailed in the structural drawings. The design and engineering of the formwork as well as its construction shall be the responsibility of the Contractor.

Formwork design shall be submitted to the COR prior to the first concrete placement.

Forms shall be properly aligned, adequately supported, and tight. The form surface shall be smooth and free from irregularities, dents, sags, or holes when used for permanently exposed faces. All exposed joints and edges shall be chamfered, unless otherwise indicated.

Forms for exposed surfaces shall be coated with a non-staining form oil, which shall be applied shortly before concrete is placed.

Formworks shall not be removed before the expiration of 24 hours after concrete placement except where otherwise specifically authorized. Also, in the case of concrete slabs, the formworks shall not be removed before the expiration of 21 days after concrete placement, except if contractor has used additives for its construction and has verified the appropriate concrete’s resistance trough a concrete test. Supporting forms and shoring shall not be removed until the concrete has cured for at least 5 days.