Terms of Reference
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DEPARTMENT OF PUBLIC WORKS & HIGHWAYS TERMS OF REFERENCE CONSULTING SERVICES FOR THE DETAILED ENGINEERING DESIGN FOR RETROFITTING/STRENGTHENING OF PERMANENT BRIDGES- DELPAN AND PANDACAN BRIDGES I. INTRODUCTION A. BACKGROUND The Government of the Philippines (GOP), through the Department of Public Works and Highways (DPWH), has engaged the services of ___________________________________, to provide consulting services for various proposed DPWH projects (Detailed Engineering Design and/or Special Studies) CY _____. The specific project that will require the services of the Consultant will be identified by the DPWH during the duration of the consultancy contract. The VFS is classified as an active fault in the Greater Metro Manila Area (GMMA) and is consisted of two segments: the 10-km long East Valley Fault (EVF) and the 100-km long West Valley Fault (WVF). Both faults are projected to be capable of generating a large earthquake of magnitudes 6.2 and 7.2, respectively, which may result to a very destructive ground shaking. On May 18, 2015, the Philippine Institute of Volcanology and Seismology of the Department of Science and Technology (DOST-PHIVOLCS) launched the VFS Atlas which is a handbook of large scale maps showing in detail areas traversed by the fault system in line with the vision of providing the people with a handy reference for traversing active faults and as guide in formulating mitigation measures and response strategies in the event of a large earthquake. Relative thereto, this Terms of Reference (TOR) shall refer to the following identified priority bridges, duly classified as critical and shall need urgent retrofitting/strengthening scheme to conform to the latest seismic code for bridges: 1. Delpan Bridge, Brgy. 286, 1st District, San Nicolas, Binondo Manila 2. Pandacan Bridge (Nagtahan Link Bridge 3), Brgy. 833, Zone 9, 6th District, Pandacan Manila. B. OBJECTIVES To upgrade the load carrying capacity and seismic resistance of the existing priority bridges as identified by NCR to prevent damage in the event of major earthquakes. Terms of Reference | Consulting Services for the Detailed Engineering Design for Retrofitting/Strengthening of Permanent Bridges in accordance with Seismic Vulnerability Rating of Bridges within 200-meter Buffer Distance of the Valley Fault System Page 2 of 7 C. PROJECT SCOPE The project involves detailed engineering design work for three (2) priority bridges as enumerated below. The detailed engineering shall include structural and foundation investigation, and the preparation of technical studies, plans and drawings, cost and quantity estimates, program of work, prequalification and bidding documents in accordance with Republic Act 9184, and other documents, as required. The bridges to be retrofitted are as follows: Total Name of Bridge Location No. of Spans Length Description (m) Brgy. 286, 1st District,San 1. Delpan Bridge Nicolas, 5 203.00 Concrete Bridge Binondo, Manila Brgy. 833, 2.Pandacan Bridge Zone 9, 6th (Nagtahan Link District, 5 148.00 Concrete Bridge Brdige 3) Pandacan, Manila Note: The above project descriptions as shown in the table shall be validated by the Consultants during the detailed engineering works. II. SCOPE OF SERVICES The Project, in general, shall consist of the detailed engineering design activities and engineering services for each bridge which include, but not limited to the following: 2.1. Performance of field investigation and surveys to determine site conditions, and all other parameters necessary to perform the Technical Studies and detailed engineering. 2.2. Preparation of Technical Studies to determine the appropriate methods and costs to upgrade the bridge structures to acceptable standards of load-carrying capacity and seismic resistance. 2.3. Based on the approved Technical Report, preparation of the final construction plans, estimates of quantities, detailed unit price analysis and cost estimates. 2.4. Field measurement of structural member shall be done for the purpose of preparing the structural as-built drawings. The following are the major items to be undertaken / conducted under this project: 2.5. The Consultant shall be responsible for performing all the investigations of the structures. Procedures to be followed as developed by the Consultant shall be in compliance with the DPWH requirements and as described in the Seismic Retrofitting Guidelines as approved or modified Terms of Reference | Consulting Services for the Detailed Engineering Design for Retrofitting/Strengthening of Permanent Bridges in accordance with Seismic Vulnerability Rating of Bridges within 200-meter Buffer Distance of the Valley Fault System Page 3 of 7 by the DPWH. The investigations may include obtaining “as-built” drawings, field survey, soils investigations, bridge member measurements, rebar scanning, concrete composite strength, other test relative to structural steel (c/o BRS/______Project and bridge condition survey/scanning as appropriate. 2.6. The Consultant shall prepare the required Technical Studies for the bridge structure in accordance with the following DPWH Specifications: • Design Guidelines Criteria Specifications (DGCS) • Bridge Seismic Design Specification (BSDS) • DPW Bridge Retrofitting Manual 2.7. The Consultant will prepare Technical Studies following the procedures given in the Seismic Retrofitting Guidelines to determine the most appropriate and economic method of strengthening the bridge and increasing its seismic resistance to acceptable levels. 2.8. The DPWH may require alternative solutions to allow for the determination of the most suitable economic scheme for implementation. 2.9. The Technical Studies shall be submitted to DPWH for approval prior to preparing the contract drawings for the bridge. 2.10. After approval by DPWH of the Technical Studies, the Consultant shall prepare the necessary construction design drawings and other contract documents for retrofitting of the bridge, based on the results and recommendations of the approved Technical Studies. 2.11. Geological and Geotechnical investigation. The Consultant shall coordinate with Regional/District Offices concerned during the conduct of geological and geotechnical investigation at proposed bridge sites. The Consultant shall conduct geotechnical investigation of at least two (2) boreholes to determine the soil bearing capacity, liquefaction potential and settlement. The Consultant shall also conduct geological investigations which shall consist of, but not limited to, the following: a. At proposed bridge sites, deep drilling with Standard Penetration Test (SPT) shall be made at each abutment and additional boring shall be done at each pier for multi-span bridges with a minimum depth of 30m. below the riverbed in ordinary soil. Standard Penetration Test (SPT) shall be made at a maximum interval of 1.50m. and at every change soil layer. Boring will be terminated when 3m. of penetration into stable strata/hard rock is encountered at shallower depth. The depth of Boreholes shall be extended beyond the minimum depth of 30m. in case hard strata (N ≥ 30) is not maintained. The RO/DEO must be officially notified by the Consultant for approval. b. The review and approval of the geotechnical investigations reports and plans (A-1 size) by the NCR-Regional Office do not relieve the Consultant(s) from the responsibility of determining the sufficiency and appropriateness of the geotechnical investigation works including the laboratory tests and evaluation results. Terms of Reference | Consulting Services for the Detailed Engineering Design for Retrofitting/Strengthening of Permanent Bridges in accordance with Seismic Vulnerability Rating of Bridges within 200-meter Buffer Distance of the Valley Fault System Page 4 of 7 The Consultant shall be able to identify areas with geological problems and difficulties, and shall conduct the following: a. Collection of available Geological information such as aerial photographs, satellite imagery, relevant geological study reports, documents and maps for the project areas. b. Geological mapping of fault lines specifically active ones that could affect the stability of proposed bridges and also determine seismicity. c. Determine if the proposed bridge sites is prone to foundation problems such as settlement and subsidence. 2.12. Strengthening of foundation and major structural repair scheme are still subject for verification of the following tests: a. Underwater exploration for determination of type and measurements of existing foundation. b. Non-destructive tests in piers and deck slab for determination of size, dimensions and spacing of bars as well as concrete compressive strength. c. Soil exploration for reference in the design of foundation retrofit. d. Differential levelling survey at the top of slab to verify whether settlement has occurred. 2.13. Provide Plans for fender piles on the piers before and after these existing piers(9&10). 2.14. In the preparation of plans, the Consultant shall use Computer Aided Design (CAD) software. After completion of the survey works and detailed design, all electronic files of reports, plans and drawings and other relevant documents shall be turned-over by the consultant to DPWH. 2.15. Detailed Engineering Design During the detailed engineering design, the consultant shall coordinate and report to NCR for uniformity and cohesiveness in the preparation of related documents, consistent with the latest edition of the Design Guidelines, Criteria and Standards for Public Works and Highways, AASHTO Guidelines