DENVER INTERNATIONAL AIRPORT GATE APRON REHABILITATION AND DRAINAGE IMPROVEMENT PROGRAM DESIGN AND CA SERVICES RFP/RFQ

Transcription

1 The following is an excerpt from the Concourse C Field Investigation Services for 2016 Design Work performed by Jacobs. This is a sample of what may be expected for future field investigation services. DESCRIPTION OF PROJECT This phase of the project will include survey, geotechnical investigation, and visual inspection of the apron areas. Site trips and review of record drawings in the project area are also included in this phase. The field investigation will be assembled to develop an understanding of existing conditions and will be to develop demolition limits required for rehabilitation of the apron pavement. The field investigation will be implemented to look at site-specific issues unique to the project site. The objective of this phase is to develop an understanding of existing conditions within the project area and to provide a recommendation for correcting this condition. The existing apron areas within the project limits are composed of Portland Cement Concrete (PCC) pavement characterized by differential movement causing surface cracking, ponding water, and drainage into the concourse. The existing pavement section is assumed to match the DIA standard airfield pavement section of 17 PCC on 20 stabilized base for all areas. Major work elements will include: Survey Site Inspection and Pavement Evaluation Geotechnical Investigation Site Inspection Summary Page 1 of 6

2 FIGURE 1. PACKAGE 2B PROJECT LIMITS SCOPE OF WORK Work elements included in this scope are as follows: 1. Progress and Coordination Meetings: Maybe include 2 progress meetings at DIA and weekly/daily coordination for field services to discuss progress and coordination with airlines and operations. Jacobs will attend progress meetings with DIA to occur every week during this phase. All meetings will be held at DIA and attended by the PM and other necessary Jacobs personnel as required. A total of 2 progress meetings are included in this item. Coordination meetings will also occur on a weekly basis during field work. It is assumed that these meetings will be teleconference conversations facilitated by Jacobs to discuss progress, schedule, and needed coordination. Jacobs will help DIA develop the agenda and relevant exhibits for discussion at the meetings. DIA will prepare and distribute the meeting minutes. 2. Site Inspection Summary: Jacobs will prepare a Site Inspection summary that will include the following items: 2.1. Topographic Survey: The Jacobs team will collect survey data of topographical conditions of existing apron pavement, lighting, drainage, utilities, and other surface fixtures. This task will include a 1-day pre-survey site visit to become familiar with the site and a pre-work meeting and work plan to be coordinated with the DIA survey section. Survey and utility locations will reference the DIA Low Distortion Projection (LDP) using control points established with the DIA Survey Section. Finished survey models will be provided to the DIA Survey Section for review and approval. Topographic and infrastructure features will be collected using robotic total stations within the project boundaries and outside of the existing laser scan point cloud range. The laser scans and extracted data from the building face will be incorporated from Authorization 38 for the Concourse Perimeter Page 2 of 6

3 Survey project. The scope of work for Authorization 38 provides laser scanning and collection of data within 50 feet of the concourse footprint. Specific features associated to GIS data collection requirements will be extracted and incorporated into the design survey for this project. Additional features not compiled to meet the scope requirements for Authorization 38 will also be extracted from the existing laser scanning point clouds. It is assumed that the survey will be completed during nighttime hours with an escort provided by DIA. Horizontal and vertical values for existing concourse perimeter control points will be used as initial points and check points for the surveys Design data will capture differential settlement, ponding, heaving, and all four corners of each concrete panel and permanent above ground features including bollards, above-ground utilities, jet-bridges, PC-air units, potable water cabinets, and surface paint. Positional accuracy will meet a vertical and horizontal tolerance of 0.04 feet. The survey is expected to be completed in 8 weeks. Utilities anticipated within the project limits include electrical, gas, communications, potable water, jet fuel systems sanitary sewer, and storm drainage including storm drain (SDG) and deicing waste (DIW). Underground utilities will be horizontally located and marked based on record mapping, verbal recollections, and surface evidence. Conductive toneable utilities will be identified using Radio Frequency Induction (RFI) locators and/or 2-D Ground Penetrating Radar (GPR). A utility sweep will be performed to investigate the presence of unknown utilities. The utility sweep will include RFI locators using inductive methods and passive frequency methods. GPR will provide a utility sweep for conductive and non-conductive utilities, linear features and non-linear features. Utilities, linear features and non-linear features will be marked in the field using standard marking paint and/or flags in accordance with DIA requirements. The positions of the designated utilities and linear features will be surveyed by total station or Real-Time Kinematic (RTK) Global Navigation Satellite System (GNSS) methods. Utility information will be integrated into the final multilayered CAD deliverable. Positional accuracy for underground utility marks will meet a horizontal tolerance of one foot or less and a surveyed horizontal tolerance of 0.1 feet. The utilities investigation is expected to be completed in 14 days. A total of 9 weeks is anticipated to process and extract the survey data. The ground survey and subsurface utility locations completed as part of this scope will be developed into a BIM model. A Civil 3D model including creation of pipe networks and attaching attribute blocks will be created and delivered electronically to DIA as the existing conditions model Engineering Soils Investigations: The Jacobs team will be responsible for conducting all engineering soils investigations required to complete the analysis of the project. A sub-consultant to Jacobs will be utilized to complete this work. Jacobs will assist the subconsultant in development of their scope and fee, coordination of site activities including final placement of boring locations, and review of preliminary deliverables. The subsurface investigation will be completed in two phases using Non-Destructive Testing (NDT) techniques followed by borings and corings to better Page 3 of 6

4 characterize material properties. Heavy falling weight deflectometer (HWD) testing will be completed to provide an understanding of sub-surface variability and areas of weakness. This information will be used to refine the location for borings in an effort to target specific areas of concern. It is assumed that 15 borings will be drilled to obtain information on the subsurface profile to obtain samples for laboratory testing and to estimate the groundwater level and depth to bedrock, if encountered, within the drilled depth. The borings will range in depth from about 15-feet to 30-feet. The geotechnical subconsultant will look for indications of seepage in the geotextile bond breaker, which has been found in numerous other borings. Samples will be obtained at 2- to 5-foot intervals for evaluation of penetration resistance (blow counts) and moisture distribution in the select fill, as well as evaluation of moisture and swell distribution in the upper few feet of the underlying claystone bedrock. The subconsultant will coordinate utility locates with the Utility Notification Center of Colorado and with the project survey prior to drilling. Borings will be made by drilling four-inch diameter, continuous flight power augers to drill the borings. Relatively undisturbed samples will be obtained with a modified California sampler similar to ASTM Method D Coring of the existing concrete airside pavement will be necessary prior to drilling. The concrete pavement at each core location will be patched in accordance with DIA requirements. The subconsultant will core the PCC and CTB to a depth of approximately 2 feet, and then obtain samples of the CTS or LTS and subgrade with soil sampling equipment. Drilling will be performed at night between the hours of 11:00 p.m. and 6:00 a.m. This work is expected to be completed in 4 nights. Laboratory testing will be completed on selected samples obtained from the borings to determine the following: Moisture content; Density of undisturbed fine-grained samples; Gradation characteristics; Consolidation and/or swell potential of undisturbed samples; Atterberg limits; Moisture-density relationships in accordance with standard Proctor; California Bearing Ratio; and Water Soluble Sulfates. Page 4 of 6

5 The results will be analyzed and delivered in report format to provide geotechnical recommendations and discussions to characterize the potential for future heave and settlement and mitigation measures Site Inspection: Jacobs will coordinate and facilitate on-site inspection to develop an understanding of site conditions. A subconsultant to Jacobs will perform this work Record Drawings: Jacobs will review existing record drawings and GIS data provided by the Client prior to scheduling and conducting the site inspection of the apron areas. The geotechnical subconsultant will review previous exploration data and reports from the project areas Pavement Investigation: The Jacobs team will walk the apron areas within the project site over a 3-day period to provide a qualitative assessment of each panel including pavement condition, cracking, spalling, low spots, signs of differential settlement, and joint condition. It is assumed that the site inspection will occur during day time hours giving way to ground operations. Jacobs will include the services of a pavement sub-consultant during this investigation. NDT will be performed on the apron within the project limits identified in Figure 1 at project level frequency in accordance with the requirements of FAA Advisory Circular 150/ A, Use of Nondestructive Testing in the Evaluation of Airport Pavements. NDTs shall be performed at 25-ft to 100-ft longitudinal or transverse locations depending upon aircraft locations at the time of testing. This will provide a pattern of testing to properly analyze the area. Based on the assumed test spacing, approximately 140to 175NDTs will be required over about two (2) days, assuming 8 hours of uninterrupted time. NDTs will be conducted during night hours, as necessary, after coordination with Airport Operations. Security escort will be provided by Jacobs or the airport during the NDT. NDT data will be reduced in accordance with FAA Advisory Circular 150/ A using closed form and layered elastic back-calculation methods. The back-calculations will provide in-situ moduli of subgrade reaction (k) and subgrade elastic moduli (E). Each nondestructive test will provide data equivalent to plate load and CBR tests at each of the test locations with reduced operational impacts based on time. Each test location will be recorded using GPS collection and reviewed in accordance with the recorded distresses obtained during the site inspection. The processed NDT data will also be used to model pavement response and boring locations for conventional testing. Finally, given the age of the existing pavement and the dates of original construction, it is understood that alkali silica reaction (ASR) may be present in select slabs. ASR could be contributing to distresses and serviceability problems noted on the apron therefore, this task includes a petrographic analysis on up to 3 coring samples within the project site Site Inspection Summary: Jacobs will compile record documents, geotechnical reports, pictures, field notes, and the pavement condition assessment. This information will be organized by Page 5 of 6

6 each aircraft gate. Effort will include presenting field notes into electronic format. In addition, an interim geotechnical report will be prepared by the geotechnical subconsultant to compare site observations and previous investigations completed by the subconsultant within the project area. The interim geotechnical report will include old boring logs and laboratory test data, a summary of the current issues and problem areas, and discussion of conceptual remedial approaches for the geotechnical issues identified. Page 6 of 6