J-1-1_Statement_of_Work.pdf

SECTION C DESCRIPTION/SPECIFICATIONS/WORK STATEMENT

REMODELING OF THE WOMEN’S BARRACKS FOR THE

POLICE ACADEMY AT MURCIELAGO

COSTA RICA

BACKGROUND

The Embassy of the United States of America, through the International Narcotics and Law Enforcement (INL)

Affairs Office, and in cooperation with the Costa Rican Police Academy, is heading an infrastructure improvement project of the Police Academy training site at Murcielago. The goal of the project is to improve the barracks facilities used by the women students during their assigned periods of training.

The overall intent of the contractual effort for this project is to remodel the existing building according to the architectural design that has been performed by the INL technical advisor. The existing building is located at the Murcielago Police Academy training site, in the vicinity of Cuajiniquil de La Cruz, Guanacaste, Costa Rica, (approximately 168 miles from San Jose. See drawing G-02.)

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

Preliminary work includes the construction of temporary facilities according to the specifications detailed in

Section 3.1.

Also preliminary work includes the demolition of the existing walls, windows and doors that are no longer needed in order to accomplish with the new architectural distribution.

The preliminary work includes the conditioning of the area in order to perform the remodeling of the building and complete the final designs, these includes the following:

Demolition of the existing walls, windows and doors that are no longer needed in order to accomplish with the new architectural distribution (see drawing A-01.).

Dismounting of the existing roof and existing fascia. (see drawing A-01.).

Demolition of the existing laundry. (see drawing A-01.).

C.1.2 Structure for Bathroom and Laundry

The contractor shall build the appropriate structure for the extension of the bathrooms (area 103 between axis 2 and 4 and between axis A to D see drawing A-02. ) and for the new Laundry (area 105 between axis 5 to 6 and between B to C) in order to accomplish with the new architectural design detailed in drawing A-03. and A-04..

The design was be based on concrete (for foundations and columns see drawing S1.1) and a metallic structure

(for the roof see drawings A-05., S4.1 and S5.1) covered with a thermal and acoustic roof (the thermal acoustic roof is included in section C.1.6). The floor shall be built with reinforced concrete (minimum thickness 10cm) and covered with ceramic tiles according to the specifications see drawing A-06. (included in section C.1. 5).

The design has to accomplish with the local construction regulations established by the MSA (Health Ministry) and the CFIA (Colegio Federado de Ingenieros y Arquitectos de Costa Rica)

In order to develop the bathrooms for women (area 103 between axis 2 and 4 and between axis A to D see drawing A-02. ), the contractor shall demolish the floor of the existing bathrooms and shall build a new concrete floor according to the new architectural distribution including the extension. The new floor shall be constructed according to detail #3 specified at drawing S1.1.

C.1.3 Construction of new walls and façade coatings

The contractor shall build the walls according to the architectural drawings (A-02., A-03., A-04.) and Structural drawings S1.1 and S2.1 and these specifications, nevertheless the contractor shall guarantee the stability of the walls, therefore the contractor shall include any type of reinforcement that he considers and that is not included in these specifications and drawings.

The walls shall be constructed with prefab concrete units (Prefa PC) and finished with plaster (stucco) according to the materials specifications, this type of finish will also be applied to the existing exterior and interior concrete walls in the areas that are visible and in the area of the improvement that are detailed in drawings.

For the renovation of facades the contractor shall build coatings according the respective material specification and according to drawings A-02., A-03. and A-04.. The “coating for façade” refers to the wall that covers part of the facade from a concrete wall (Prefa PC) to the roof. This coating shall be done at the exterior side using aluminum panels and at the interior with dense glass gypsum panels (for humid areas of 12,6 mm) supported in a metallic structure.

Also the wall located at axel 3 that divides the barrack building in two separated areas shall have an interior coating from the concrete wall to the roof according to drawings A-02., A-03. and A-04.. This wall shall be assembled with galvanized metallic supports and gypsum panels in the two sides (as a sandwich). The contractor shall design and build this wall using dense glass gypsum panels for humid areas of 12,6 mm.

Some internal walls shall be constructed using light gage metallic structure 4” thick gage 20 with dense glass gypsum panels 12,6mm (each side) and finished with dry bond plaster and acrylic paint.

Some partitions walls on toilets and showers shall be construted using stainless steel 316 systems gage 1/16”.

The contractor shall guarantee the stability and operability of the partitions doors and al the fixtures.

C.1.4 Floors Renovation

For this project a renovation of floors shall be performed according the following:

The bathroom (area 103 between axis 2 and 4 and between axis A to D see drawing A-02. ), the exterior hall

(area 100 marked between axis F to G), and the new laundry (area 105 between axis 5 to 6 and between B to C) shall be covered with new antiskid ceramic tile floor according to the specifications and drawing A-06..

The barracks for women (area 101 between axis D to F and between axis 1 to 6), and including the dressing rooms (area 102) shall be covered with new Porcelain floor tiles (Porcelanato) according to the specifications and drawing A-02. and A-06..

According to drawing A-02. and A-06. the sidewalks (Area 104) shall be reconstructed, the sidewalks shall be constructed with concrete (f’c=210kg/cm2) of 10 cm high and reinforced with electro-welded mesh

(150x150x6.35mm, and a broom finish shall be applied according to the respective specification.

Between the finished floors and the interior walls mop boards of timber or vinyl shall be provided and installed by the Contractor (see finishing schedule at drawing A02/19, A-03. and A-04.), except for those areas that the walls are covered with ceramic tiles.

C.1.5 Roof and Fascia

The Women’s’ Barracks shall be covered with new thermal-acoustic roof according to the specification an according drawing A-05., the new roof shall cover the existing area, the extended area (Bathroom) and also the new laundry, for this purpose the contractor shall also paint the existing metallic structure with two layers of antirust paint and two layers of enamel paint. The structural details for the roof structure are shown on drawings

S4.1 and S5.1.

The Contractor shall also design and build the respective roof ridge, valley and edges with metallic elements recommended by the manufacturer of the thermal-acoustic roof.

The Contractor shall also design and build a new fascia according to drawings A-05., and S5.1. The fascia shall be constructed with gypsum panels for humidity zones of 9mm supported with galvanized metallic shapes.

C.1.6 Finishing, Windows and Doors

New ceramic wall tiles shall be provided and installed by the Contractor in the bathrooms (area 103) and in the laundry (area 105 between axis 5 to 6 and between B to C) according to drawings A-02., A-04. and A-07. The new ceramic wall tile shall be according to the respective specification.

All the walls of the project shall be painted with acrylic paint according to the spec except for those that are covered with ceramic tiles. The paint shall include the existing walls at the interior and exterior areas of the building.

Also the existing metallic structure of the building shall be painted with enamel in order to provide an appropriate maintenance of the facilities. The contractor shall cover with two layers of enamel. Check drawing

S0.1 y S0.2 for thickness specifications.

Regarding the countertops for the barrack’s bathrooms (area 103) the contractor shall build it with granite according to the respective specification. The Contractor shall guarantee the stability of the Countertop that will support the washbasins.

New windows shal be provided for the bathroom (area 103 between axis 2 and 4 and between axis A to D see drawing A-02. ), the exterior hall (area 100 marked between axis F to G), and the new laundry (area 105 between axis 5 to 6 and between B to C).

The Contractor shall provide new doors to the women barrack building including the existing and the new areas according to the respective specification and to drawing A-07.

C.1.7 Hydraulic and Sanitary Systems

Construction of a potable water system:

Following the specifications stated in the project and drawings M1.2 and M1.3, the contractor shall design, provide, place, connect, fix and test all the pipes, accessories and special items, as well as the required valves, which together will serve to conduct potable water. The potable water comes from an existing source that is providing water to the current bathrooms (see location in drawing G-02.). The Contractor shall include all the accessories needed to connect the building to the existing water system.

Also the contractor has to design and build the pipe line for the hose cabinets of the fire protection system shown on detail #1 on drawing M1.4. For this design the contractor shall review and test the existing water service. The water connection for this fire protection system shall be taken from the existing supply that correctly is providing water to the building (see location in drawing M1.2 and detail M-01.4). If the

Contractor’s study determine that there is not enough pressure to provide water to the hose cabinets the contractor will propose solution that will be analyzed through a contract modification.

The system shall follow the local regulations and the regulations of the American Water Works Association

(AWWA), and the National Standard Plumbing Code (NSPC).

Construction of the Sewer System:

The Contractor shall design and build the sewer system to meet the basic requirements identified in drawings G-

02. and M1.1. The Contractor shall provide, place, connect and satisfactorily test the pipes, revision points, and other devices of the entire sewer systems for the barracks’ bathrooms (area 103). Requirements include a connection to an existing sewage system located besides the building (see location in drawing G-02.) to provide appropriate drainage of wastewater from the bathrooms and the construction of inspection wells constructed with reinforced concrete as it is detailed in drawing M1.4.

Also the contractor shall design and build metallic gutters to collect the rainy water from the roof. The contractor can use the existing metallic gutter that does not have holes or that is not bent. The contractor shall design and build a fluvial system to evacuate all the rainwater from the roofs, this system shall not be connected to the sewer system that collects the wasted waters from the bathrooms and laundry. This fluvial system must be a separated from the sewer system; it shall be around the buildings (Barracks and laundry) conducted to the existing dicks that are close to the area (see drawing A-05. and G-02.).

C.1.8 Construction of the Electric System

The contractor shall design and build the electric system to meet the basic requirements identified in drawings

E-01.1, E-01.2, E-01.3 and E-01.4 and according to the Local Electric Code. This must be developed and certified by a professional (Electric Engineer).

The internal electric system of the building shall be totally reconstructed including the new panel board TD1, therefor the contractor shall designed and built it according the basic requirements detailed in drawings E-01.1, E-01.2, E-01.3 and E-01.4. Also the contractor shall design and build the electric connections (outlets, pipes and cables) for the air conditioning and ventilation systems. It is needed to clarify that the ventilation system and the air conditioning system shall be designed by the Contractor, for this design review section C.1.10.

The electric supply for the building shall be from the electric line that is located in front of the building (see location in drawing G-02.). The final connection from the electric supply to the main electric boards shall be designed by the Contractor in order to have the electric service for the basic requirements.

This contract does not include the construction of the connection from the existing transformer to the main electric boards, the contractor can use the actual electric connection (transformer to the main electric boards) to provide the power, but it is needed to remark that If it the Contractor’s electric design requires an improvement of the actual connection shown in drawings, the contractor shall deliver all the drawings, specification and the economical proposal to the COR in order to process a modification. In this case INL will evaluate the request and will approve it through the CO.

C.1.9 Construction of Special Systems

Construction of the Fire Protection System:

The fire protection system includes a fire alarm system with smoke detectors, and Fire Host Cabinets that should be according to drawings A-08., E-01.4 and M-01.2.

The contractor shall design and build this system according to the mentioned drawings and shall include the equipment and pipes for the Fire Host Cabinets according to the specifications (Also review the water system).

Air Conditioning and Ventilation System:

The contractor shall design and build the air conditioning system to meet the basic requirements identified in drawing E-01.3. All the equipment for this system shall be from an United States manufacturer that has a representation in Costa Rica in order to facilitate the maintenance of the system. The pipes shall be of cooper and with an insulation protection according to the manufacturer recommendations. Also it is needed to remark that the Contractor shall include the design and build of the required drainage for the equipment to avoid leaking area in the interior of the building.

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) and the Contracting Officer

(CO) before taking any other action.

C.2.1 Quantities

This contract is based on a firm-fixed price sum. Any quantities indicated in the specifications and drawings are for reference only and the Contractor is responsible for providing quantities needed to complete the work, without any price adjustment after award.

C.2.2 Trials and tests

Materials, permanent equipment, its accessories and other elements destined for 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 the 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 ISO or its equivalent, do not need to be routinely tested. The Contractor shall account for costs of laboratory trials and tests within their firm-fixed price. 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.2.3 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.

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

Throughout the different stages of construction work, the Contractor shall obtain approval, 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.

The Contractor shall provide a construction schedule in which all the works shall be detailed with the date of performance and delivery.

C.2.4 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 contract.

C.3 SPECIFICATIONS FOR MATERIALS AND CONSTRUCTION ACTIVITIES

C.3.1 SUPPLEMENTARY WORK

C.3.1.1 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. Before starting the construction of the project the Contractor shall verify and mark all the construction levels of the different areas that shall be according the designs stablished in drawings. Once the

Contractor finish this verification and all marks are placed in the site the Contractor shall request to the COR the confirmation of these construction levels.

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

Before beginning the remodeling, 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, coordinating with the COR.

The construction axes and levels shall be marked in the building in a safe manner. The marks shall be 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.3.1.2 WARNING SIGNALS:

The Contractor shall provide all necessary signs and announcements to prevent accidents in accordance with the safety plan (see Section H.8.2), 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.

C.3.1.3 TEMPORARY STRUCTURES: OFFICES, SANITARY FACILITIES & WAREHOUSES

Temporary structures will be implemented in the existing facilities for the Contractor’s personnel, the COR, the

Government Technical Advisor (GTA). It is the Contractor’s responsibility to implement offices, warehouses, provisional bathrooms and the guardhouses required for their own use. These areas can be implemented in the existing building that is going to be demolished.

The Contractor will implement provisional offices, sanitary facilities for the personnel, and a guardhouse with a temporary connection to a potable water and sewage system prior to commencing construction. One sanitary facility shall be implemented for every 10 workers, and one for the technical staff, the COR and the GTA. The

Contractor will provide a 9 square meters office for the exclusive use of the COR, the GTA or his authorized assistants. 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. The Contractor shall ensure that the temporary facilities are clean, and provide sufficient privacy and safety for personnel.

C.3.2 EARTHWORK, EXCAVATION AND BACKFILLING

The work described in this section 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.3.2.1 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 the Contractor shall use theodolites or precision instruments. 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.3.2.2 SLOPE CONFIGURATION

Not applicable for this project.

C.3.2.3 EXCAVATION

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 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 C2.2 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:

a) 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.

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

c) 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.3.2.4 OVER EXCAVATION

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.3.2.5 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.3.2.6 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.

C.3.2.7 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 C2.2 and C3.2.8). 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.3.2.8 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.3.2. 9 BACKFILLING

Backfilling is the process of putting soil back inside a trench or in a foundation when the excavation has been completed. Backfilling shall be performed according to the architectural and structural designs. The space 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 free in general of all organic material and all the material that is not appropriate for backfilling. Advanced COR approval is required for the material that will be used for backfilling, and for the material will come from the excavation itself or other extraction sites.

The backfilling will be done according to the project specifications and according to the lines, levels and gradients described in the architectural 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 that have the Certification of Operation from the Government of

Costa Rica.

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.3.2.9.1 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. COR approval of the material that will be used in the backfilling process is required. 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 shall be included in the Contractor’s firm-fixed price.

C.3.2.9.2 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 determined in accordance with the structural and architectural detailed drawings. Prior to backfilling, the land shall be free of debris. COR advance approval is required for 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). 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.3.3 CONCRETE STRUCTURES

C.3.3.1 MATERIALS FOR CONCRETE

C.3.3.1.1 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.3.3.1.2 GRAVEL STONE AGGREGATES

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

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.3.3.1.3 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.

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.3.3.1.4 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.3.3.2 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):

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.3.3.1.1, and “fine-grained sand” under Section C3.3.1.3).

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.