APPENDIX A
ENTERANCE REPAIRS TECHNICAL PROPOSAL
Introduction For the purpose of this tender Tawazuh has adopted the concept drawings included with the specification for design purposes. the design drawings will be evolved as the project progresses and new as built drawings will be issued at handover of the project It is assumed for design purposes that no issues will arise in either ground conditions and end user requirement that will require major changes or deviations from the calculations and designs submitted. we have used the following as references when designing this project • • • • •
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UK Building Regulations The Joint Service Publication CDM Regulations The Latest British Standards or European Norm The Electricity Safety, Quality and Continuity Regulations 2002 Chartered Institute of Building Services Engineers Code
All works will be carried out to the appropriate BS specification these are detailed beside the specific task. Drawings Existing Site Plan and Proposed Task Locations. 170/BSN/STRE/2187/G/01 Typical Culvert Wing Wall Detail. 170/BSN/STRE/2187/C/01 Vehicle Gate Details. 170/10093/STD/C/081 Newey Manual Drop Arm Barrier Details. 170/BSN/STRE/2187/M/01 Scope of the overall project 1.General. To replace and repair the entranceways, barriers and culvert wings at MOB Price. 2.Location. The proposed site is at MOB PRICE, GERESHK. The location of all tasks and camp is shown on Dwg No 170/BSN/STRE/2187/G/01. Requirement 3. The user requirements are as follows: a. Install 3 No. Newey Manual Drop Arm Barriers. b. Replace approximately 25 m of damaged Mil 1 HESCO baskets in various locations. c. Replace approximately 50 m of damaged Mil 7 HESCO baskets in various locations. d. Replace 8 No. damaged 6 m vehicle gates. e. Replace 10 No. damaged culvert wing walls and paint in a black and yellow stripes pattern. f. Reinstate 6 m of V ditch behind BGHQ compound. g. Repair approximately 2 m2 concrete pavement on MEP.
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Outline scope of works 1. Installation of Newey barriers. The existing 3 No. finger barriers are shown on 170/BSN/STRE/2187/G/01 to be replaced with the installation of 3 No. Newey barriers. The barriers are to be fabricated from steel tubing and I-beams. The barriers are to be constructed at the Main Entry Point (MEP), as shown on Dwg No 170/BSN/STRE/2187/M/01. 2. Replacement of HESCO. Approximately 25 m of Mil 1 and 50 m of Mil 7 HESCO is to be replaced at various locations around MOB PRICE. The locations for the HESCO force protection can be seen on Dwg No 170/BSN/STRE/2187/G/01. 3. Culvert wing walls. A total of 10 No. damaged culvert wing walls are to be reconstructed using reinforcement on various locations as shown on Dwg No. 170/STRE/2187/G/01 and 170/BSN/STRE/2187/C/01. Concrete should be C40 and cast in-situ using suitable formworks. Wing walls are to be 200 mm in width and constructed at an angle of 450. Wing walls then are to be painted with yellow and black stripes pattern. 4. Replacement of vehicle gates. There are a total of 8 No. vehicle gates 6 m wide to be replaced at the front and rear MEPs. Details of the gates and the locations can be seen on Dwgs No. 170/BSN/STRE/2187/G/01 and 170/10093/STD/C/081. 5. V ditching. Approximately 6 m of V ditch is to be reinstated in front of the BGHQ gate and the location is shown on Dwg No. 170/BSN/STRE/2187/G/01. The V ditch should be same profile as the existing ditch. 6. Repair pavement. There are two small defective pavement areas to the front MEP which requires repairing and locations is shown on Dwg No. 170/BSN/STRE/2187/G/01. The defective area is approximately 2m2. The repaired pavement should be capable of taking all types of vehicle load. Design responsibilities 7. Tawazuh accepts responsibility for the f ollowing aspects of the project, •
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Health & safety the integrity of force protection be breached during the construction. No work should impact on the operation of the helicopter landing site (HLS). If vehicles such as cranes are to be used, it should be notified to the Authority at least 7 days in advance. for ensuring that the quality of the works meets the required standards and specification through stringent, continual and recorded QC and QA. for ensuring all designs conform to the most recent editions of BS/EN and standards identified within this PS.
Groundwork's 1. Preparatory work. Tawazuh will: a. Request a Statement of Known Services from the Deputy Facilities Manager (DFM GSK) prior to any ground works takes place. b. Identify all local services and take adequate precautions to protect such services from damage for the duration of the works. c. Inform the authority immediately if any unknown services are discovered. 3
d. Clear and remove from the site all arising. Where stockpiling is unavoidable the Authority will be informed in advance to identify a suitable area where all unwanted material can be dumped. Preliminary groundwork's 2. General. In general all excavations are to be carried out to BS 6031: Code of Practice for Earthworks and BS 8000-1: Workmanship on Building Sites. 3. Foundations. Tawazuh will level and compact sufficient material around the exterior of the existing HESCO wall to allow the construction of the proposed HESCO wall. The base will be mechanically compacted before placing and compacting fill as necessary to form the required formation levels. A minimum CBR of 10 % will be achieved . 4. Stockpiles. Any material stockpiled from levelling is to be hauled and dumped at a suitable area away from MOB PRICE and levelled. Every effort will be made to reduce any dust or FOD hazard during construction. 5. HESCO Bastion Concertainer wall. The sections of wall are to be placed onto the firm foundation. Joints between sections are to be made using the propriety-jointing pin prior to backfilling with the specified fill material. The baskets are to be connected by joining pins supplied. Plastic ties that are supplied are to be used to close the geotextile together at the top of the unit ends to prevent the fill material from falling between the unit joints. 6. Placing fill. All HESCO Bastion Concertainer baskets are to be free from loose soil, rubbish and standing water prior to being filled. The fill will be placed and compacted in 150 – 300 mm layers. Filling is to proceed along the full length of the structure in incremental lifts. The fill is to be a sand/gravel mix 0 – 75 mm with no more than 30 % fines. Concrete Work 1. General. An RC40 mix design be used in all Culvert work to achieve the following specifications a. 28 day compressive strength on pavement - 40 N/mm². b. 28 day compressive strength on culvert wing walls – 40 N/mm². 2. Construction of formwork. The formwork is to be secured and then inspected by the Authority to ensure it is structurally sound and meets the required specifications. 72 hrs notice will be given prior to formwork inspection. 3. Reinforcement bar. It is to be placed with a minimum 50 mm end-cover in all directions from formwork prior to the concrete being poured. 72 hrs notice will be given before the pour so inspection can be done. 4. Placing. The following procedures will be used during pour: a. Place as soon as practicable after mixing and while sufficiently plastic for full compaction. After discharge from the mixer no water will be added. b. Ensure that temperature of concrete is not more than 30 deg C in hot weather and not less than 5 deg C in cold weather. c. Do not discharge from an excessive height or through reinforcement or other obstructions in a way which may cause uneven dispersal, segregation or loss of ingredients or adversely affect the formwork or formed finishes. d. Place in layers no thicker than can be effectively compacted with the equipment being used, without delay between layers. Merge together by compaction. f. Do not use vibrators to make concrete flow horizontally into position, except where necessary to achieve full compaction under void formers and cast in accessories and at vertical joints. 4
5. Compacting: Compact concrete to full depth (until air bubbles cease to appear on the top surface), especially around reinforcement, cast-in accessories, into corners of formwork and at joints. Ensure amalgamation with previous batches, but do not damage adjacent partly hardened concrete. a spud type vibrator will be used. 6 Concrete finish. Carry out all finishing operations at optimum times in relation to the setting and hardening of the concrete. Do not wet surfaces of concrete to assist surface working. Do not sprinkle cement on to the surface. Use a hand or skip float to give an even surface with no ridges or steps. The surface of the concrete shall receive no special treatment other than finishing operations required to produce the specified degree of accuracy of the surface level. 7 Admixtures. Air entrainment shall be used to give a minimum air content of 3.5% in the top 50 mm of the concrete. The air-entraining admixture shall comply with BS 5075: Part 2. Plasticisers or water reducing admixtures shall comply with BS EN 480. Admixtures containing calcium chloride shall not be used. All admixtures used are to be approved by the Authority. 8 Aggregate. Aggregates for all pavement concrete and wing walls shall be natural and a nominal size of 20 mm. 9. Quality control of concrete strength. Sampling and testing for compliance with the specified characteristic strength of designed mixes shall be in accordance with BS 5328: Part 4. The Authority reserves the right to test alongside the Contractor. 10. Workability. The workability of the concrete at the point of placing shall enable the concrete to be fully compacted and finished without undue flow. 11. Curing and Protecting. Prevent surface evaporation from concrete surfaces by covering with a suitable curing membrane or system as soon as practicable after completion of placing and compacting, removing only to permit any finishing operations and replacing immediately thereafter, or applying a suitable curing agent. Adequately protect concrete fr om shock, indentation and physical damage. Alternative curing compounds may be submitted to the Authority for agreement prior to use. 12. Hazardous, aggressive or unstable materials. The Contractor is not to import or use fill materials which would either in themselves or in combination with other material or ground water, give rise to health hazards, damage buildings or structures. The construction materials should not include any finishes that may lead to shedding of particles. WELDING WORK 1. The inspection, testing and approval of the welders and the welding of, low carbon steel work may be carried out by an independent inspecting authority as necessary. 2. Welding shall be: a. To Class II by electric arc process to BS 2971: using welding materials to BS 639. b. To Class II by oxy-acetylene process to BS 2640: using welding materials to BS 1453. Competency of Welders and Test Welds 3. Welders holding valid provisional certificates may carry out welding subject to being under the constant supervision of a person currently competent for the work in hand. 4. All certificates (originals, not photocopies) shall be submitted for inspection and recording before work commences. Where certificates of competency are not available the contractor shall submit written evidence/reference of works carried out in similar tasks. 5. The welder shall be required before or during the work to carry out a specimen butt, lap joint and round section connection fusion test in accordance with BS 4872 Part 1 procedures and acceptance levels. He is also required to submit a test piece of welding work to the Authority in advance. 6. If the welder cannot meet the requirements of BS 4872 Part 1 this person shall be replaced by a competent welder who shall also be subjected to the same test requirements. 5
7. A welder approval test record to Appendix B of BS 4872 Part 1 showing results of visual examinations and destructive tests shall be made out for each test and each welder tested. INSPECTION, TESTING AND COMMISSIONING 1. Inspection. All materials, installations and construction can be inspected by the client at anytime 2. Commissioning. All commissioning is to be carried out in strict accordance to BS/EN codes of practice, noting any expedient regulations pertaining to specialist equipments or installations. 3. Notification. The Authorities will be informed in writing at least 7 days in advance of any tests and commissioning being carried out. Access will be available to the Authorities Representative to carry out testing as deemed necessary by the Authorities Representative. Civil testing and inspection 4. Tawazuh accepts responsibility for ensuring that the quality of the works meets the required standards and specification. a. Concrete testing. any testing of concrete required is to be done by The Authority and at their own expenses.
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