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UNOPS eSourcing v2017.1 Section II: Schedule of Requirements eSourcing reference: RFQ/2020/15086 Terms of Reference Foundation Investigation for health facilities in Hlaing Thar Yar Township in Yangon Region of Myanmar 1.0 SCOPE The works for soil investigation shall be carried out in accordance with the specification set out below and as directed by the UNOPS, wherever necessary. The main scope of the work shall include but not limited to the following: ● Performing Site-Specific Ground Motion Study for Seismic Design of Building, ● Soil Liquefaction assessment during Seismic events and foundation recommendations to mitigate liquefaction effects The detail scope is indicated in the section 2.2- reporting below. The scope of the work conform to the relevant Standards on Soils and Foundations for field investigations and Laboratory testing. Reference to any code in these TOR shall mean the latest revision of the code unless otherwise mentioned. In the event of any conflict between the requirements in these TOR and the referred codes, the former shall govern. 2.0 TECHNICAL REQUIREMENTS 2.1 GENERAL The purpose of the proposed sub-soil investigation is to provide adequate information on sub-surface and surface conditions for the foundations and other sub-structures for the proposed project, with special attention to the analysis of liquefied soils, leading to safe foundation design and site specific ground motion study for determining spectral parameters for design of superstructure. The planning of the work, choice of the method of boring, selection of the type of samples and procedure for sampling though indicated in the TOR. Tenderer, however, shall furnish their tentative programme regarding the above along with its offer which, necessarily, should take into account the site conditions and time schedule for completing the work, comprising subsurface features, borings, in-situ tests, sampling, visual observations and laboratory tests of samples, reporting of the test results, including discussions, correlating the field and the laboratory test values and commendations. This TOR cover the work pertaining to site specific ground motion study and subsoil investigations and recommendations for economical and safe design of foundations and substructures for the proposed project site. 1 UNOPS eSourcing v2017.1 2.1.1 Location of buildings UNOPS would like to collect sufficient information in relation to the scope identified in section 1.0 for two buildings at coordinates 16°52'44.31"N 96° 4'34.50"E in Ward 2 of Hlaing Thar Yar Township of Yangon region. The area is 320Ft x 120Ft and please see the location map below. Building Location and proposed borehole locations 2 UNOPS eSourcing v2017.1 ⚫ ⚫ ⚫ ⚫ Total number of boreholes = 4 2.1.2 General Requirements from Contractor The CONTRACTOR shall have on site all required survey instruments to carry out the work accurately according to this TOR. All the specified locations for boreholes and field tests shall be set out at site by the CONTRACTOR from two established reference grid lines which will be shown to the company by the UNOPS Engineer. If required, the CONTRACTOR shall set out the base lines and the locations of boreholes and field tests with reference to the property line as indicated by the UNOPS Engineer. At each location of boreholes, plate load tests and other field tests, the CONTRACTOR shall establish the coordinates (X, Y, Z) prior to commencing of the operations. The coordinates shall be related to an established benchmark or to a GTS benchmark or as directed by the UNOPS Engineer. If the area, where the field tests are located, is likely to be inundated by flooding waters, the field work shall include provision for temporary fill, erection and removal of platforms, making good the ground, access, etc., as necessary for carrying out the work in this area. No extra payment for such cases in due, but whatever has covered in the Bill of Quantities under the Soil/Geo Investigation task’s cost. 2.1.3 Mobilization The Contractor shall mobilize adequate plants and equipment, instruments and personnel (skilled and unskilled) required to carry out the soil investigation work, including access, filling, provision of platforms, etc. This scope also includes demobilization of all equipment / personnel in orderly manner so as to keep the site clean for any further work by Owner. No extra payment for such activities in due, but whatever has been covered in the Bill of Quantities under the Soil/Geo Investigation task’s cost. Based on the field examination or tests, bore logs shall be prepared in accordance with ASTM D2487. On completion of the field records, the soil investigator shall discuss and decide in consultation with the UNOPS’ geo technical guidance, the schedule of tests to be performed and the exact number of samples to be tested for each test. 2.1.4 Borehole Depth The depth of each borehole should comply with Myanmar National Building Code requirements and should be carried out to a depth of 30 meters to establish the significant soil strata and ground variation. Appropriate boring methods shall be used and Hand auger boring can only be used as a supplement to other boring methods. 2.1.5 Termination Criteria If a very hard stratum is met within the borehole at depths shallower than specified in section 2.1.4, the borehole shall be advanced by coring using double tube core barrel. The borehole may be terminated 5m below the depth where N > 100 values are obtained consistently. Coring the bore hole shall be burnt by contractor until UNOPS Engineer Satisfaction enabled 3 UNOPS eSourcing v2017.1 2.1.6 Site specific seismic Ground Motion Study and Return period Site specific seismic data in terms of earthquake magnitude (Mw) and spectral accelerations (PGA, 0.2 s, and 1.0 s) should be provided for a return period of 475 years and 2475 years. The 475 year return period corresponds to a 10% probability of exceedance in 50 years and the 2475 year return period to a 2% probability of exceedance in 50 years. The need for site specific ground motion study is provided in Annexure A 2.1.7 Liquefaction analysis SPT tests every 3 ft (1 m) and where the strata changes, Granulometry analysis; volumetric net weight, dry weight and saturated weight, photographs of all samples recovered and location of the Ground Water Table for at least 20 first meters below ground level. Historical high/maximum level of ground water table should be provided since Liquefaction analysis is based not on the current elevation of ground water level but on the historical high level. Liquefaction potential for the site should be based on based on peak ground acceleration at 500 and 2500 year return periods. The need for Liquefaction analysis and additional criteria are provided in Annexure B 2.1.8 Backfilling of boreholes On completion of boreholes, backfilling shall be carried out with an approved material as and when directed by the UNOPS Engineer. Unless otherwise specified, the excavated soil shall be used for the purpose. 2.1.9 Termination Criteria If a very hard stratum is met within the borehole at depths shallower than specified in tender documents, the borehole shall be advanced by coring using double tube core barrel. The borehole may be terminated 3m below the depth where N > 75 values are obtained consistently. Coring the bore hole shall be burnt by contractor until UNOPS Engineer Satisfaction enabled. 2.1.10 Return period Seismic data in terms of earthquake magnitude and acceleration for a return period of 500 years and 2500 years. Identifying the peak ground acceleration for the area and analyse the liquefaction potential at 500 and 2500 year return periods 2.2 REPORT Two copies of Draft\Interim Report shall be submitted to UNOPS Engineer before preparing the Final Report. The record shall be prepared with due regards to above given requirements in a draft format and submitted for review and comment as soon as field and laboratory works are completed. Contractor shall incorporate the comments/ remarks, if any, furnished by UNOPS upon review of the Draft Report and submit the final report. The draft copy of the report shall in general include but not be limited to the following: ● Plot plan showing all the test locations with respect to reference benchmark. ● General Geological information of the site ● Character and genesis of soil ● Procedure of investigation and methods of various testing adopted. ● Detailed bore-logs indicating bore hole no., co-ordinates (X,Y,Z reduced levels), depth of ground water table, sub soil profile depth wise, in-situ tests like SPT and other lab results etc. See Annexure 4 UNOPS eSourcing v2017.1 B, for additional data to be noted in the Bore log for Liquefaction Analysis. ● Generalized soil profile of the underlying strata in cross section and longitudinal section wise, shall be furnished based on the bore log in grid pattern ● Particle size distribution for all materials from samples taken at regular intervals ● Atterberg Limits: Liquid and Plastic Limits and Plasticity Index for cohesive soils from samples taken at regular intervals ● Undrained shear strength for cohesive soils from undisturbed samples taken at regular intervals ● All field and laboratory test results shall be plotted against depth and also in tabular form ● Summary of results obtained from various tests and other interpretations to evaluate various soil parameters. ● Based on the site soil properties, the site shall be classified as Site Class A, B, C, D, E or F based on Table 3.4.2 of Myanmar NBC 2016 ● Recommend site specific spectral accelerations per ASCE 7-16, chapter 21. See section 2.1.6 and Annexure A ● Identify if the soil is expansive in nature, and if expansive soil provide recommendation to support slab on grade (i.e.