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The construction of Line C in Rome is being funded by the Italian government (70%), the re- gional government (12%), and the municipal rail- way company (18%). Projected construction costs for Line C are 29 million Euro/km for the at-grade segment, 105 million Euro/km for the middle seg- ment, and 150 million Euro/km for the core seg- ment. Revenue collected by STA from parking fees, fines, and permits contributes to the funding of the ITS program. In Milan, funding for the various improvement projects comes from the state, regional, and local governments as well as from ATM. ATM officials noted conversion of the 1.6-km light rail segment to an at-grade heavy rail operation is approximately 8 times more cost effective than an underground ex- pansion would have been. The cost of implementing an electronic-magnetic ticketing system is estimated at t100 million, of which 75% is provided by ATM and 25% by the regional and local governments. Operational In 2000, the AM formed a subsidiary operations company, Attiko Metro Operations Company (AMOC), to operate and maintain the new lines. By the second year of operation, the operating cost/re- covery ratio exceeded 100%. The first-year recovery ratio totaled 83%; it then increased to 148% in 2001 and declined to 139% in 2002. The operational sur- plus used to pay back the loan went from t12.7 mil- lion in 2001 to t17.0 million for the period between January and September 2003. The operations com- pany credited low maintenance costs and high rider- ship for the gains in revenue. Also, to be more cost efficient, AMOC contracts out certain functions, such as cleaning the trains and stations and main- taining the escalators and elevators. In Naples, revenues are lower than operating costs for the section of the metro system currently operating. The Italian government provides funding to cover the difference. As part of the regional transportation plan in Naples, an integrated, distance-based fare policy was implemented on January 1, 2003. A consortium of 13 train and bus companies or agencies, Unicocampania, was formed to carry out this initia- tive. To get the companies to agree to the new pol- icy, a system to guarantee that companies would not lose money as a result of the change had to be es- tablished. To do this, the ratio between transporta- tion usage revenue and profits was established for each company; and subsidies based on those ratios would be made, with the subsidies to end in the fourth year of implementation. To increase fare-box revenue, marketing and promotional campaigns are aimed at getting riders to purchase a monthly pass, versus daily or single- use tickets. MN officials reported that this effort helps to prevent fare evasion, which was estimated at 9.5% in 2000. In addition, MN collects 5% of its revenue from concession stands and advertising fees. Since 2000, Met.Ro has been required to cover 35% of its maintenance costs. The remaining amount is funded by the state. Plans to increase revenue in- clude concessions and advertising in the stations and on the trains. Efforts to increase operational efficiency focus on the competitive procurement of maintenance and operational contracts. ATM currently has a fare-box recovery rate of 53% with the remaining costs covered by the state. To increase the fare-box recovery percentage, ATM has instituted competitive bidding for contracts. Contracts are based on cost per kilometer to operate the system exclusive of maintenance costs. The region that encompasses Milan also con- tributes to the operation of the public transport sys- tem. It provides approximately 46% of ATMâs op- erating costs. ATM has agreed with the regional government to decrease operating costs and increase ridership so the amount the region contributes will decrease. Officials at ATM stated that the regionâs contribution to supporting the public transport sys- tem has declined since 2002. ATM devotes an average of over t50 million a year in renewing its fleets of buses, trolley buses, trams, and metro trains. CONSTRUCTION Environmental Process Greek law requires that every construction project obtain an environmental permit. In order to obtain the permit, the transit agency is required to prepare a preliminary Environmental Impact Assessment (EIA) during the design phase of a proj- ect and then a final EIA report. These reports cover technical, operational, and project characteristics, such as demography, traffic, climate, geology, hydrology, archaeology, air qual- 8
ity, flora, fauna, and land use issues, as well as the potential impacts related to local businesses, vibra- tion, dust, traffic, water and power supply networks, and urban environment aesthetics. Any major im- pact is addressed with proposed mitigation mea- sures. For AM, archaeological concerns are a sig- nificant component of these reports. These reports are then sent to multiple govern- ment agencies, including the affected local govern- ments, for review, comment, and approval. As part of the comment period, the local government in- forms the public and solicits input. If the project is approved, a permit is granted. In some instances, projects are approved with conditions attached. Once the permit is granted, environmental auditors monitor compliance with the environmental re- quirements and conditions. The public can challenge the approval of a project by appealing to the judicial system. EIA reports are also required in Italy. In 1996, a presidential decree was issued to increase the au- thority of the regions and decrease that of the central government. In the past, conflicts between these two levels of government have caused delays in the de- velopment of EIAs. An EIA in Italy covers the description of the project, an evaluation of the installation methods, impacts on existing systems, assessment of techno- logical and technical solutions, quantification of the various technical impacts associated with the con- struction and operation of the system, evaluation of the socioeconomic impacts, screening and compar- ative analysis of different alternatives, and the iden- tification of the major modifications needed to min- imize or eliminate unacceptable impacts, as well as environmental sustainability issues. Due to the sig- nificant archaeological issues facing these ancient cities, developing the EIA reports are an important step in the construction process. Geotechnical and Tunneling Athens Before the OMC began constructing the base project in Athens, the geology and geotechnical con- ditions along the 19-km alignment were extensively investigated, analyzed, and evaluated. The results of these investigations were used to develop the geo- technical parameters required for the safe design of the tunnels, stations, and other underground works. The OMC was responsible for all geotechnical work and assumed 100% of the responsibility and risks. The geology of the Attica region is a compli- cated stratigraphy of sedimentary formations and a variety of magmatic types. The subsoil has a com- plex structural geology that varies significantly both vertically and horizontally. Initial planning had assumed that layers of hard rock would be tough to penetrate but easy to stabi- lize. However, once tunneling began, engineers found variations in the solid rock, very soft soil con- ditions, and other anomalies, such as illegal under- ground sewage connections, deteriorated sewer lines, old riverbeds, and ancient wells. In order to protect the safety of the construction crews and the structural integrity of the ancient historical sites above ground, a series of pilot tunnels about 3 m wide were constructed to allow engineers to test the soil and determine its condition before proceeding with the actual tunneling excavations. Geological conditions also required considera- tion of vibration mitigation. As a result, AM pro- vided noise and vibration protection of the trackway. The track work is a concrete ballast system with elastic pads specified between the rail and the two block concrete sleepers. A special rubber boot is also provided between the sleeper and roadbed. For the alignment near the ancient Acropolis, a full float- ing slab was constructed. Several tunneling methods that included differ- ent structural lining configurations were employed to satisfy the requirements of the site-specific geo- logical formations: Tunnel Boring Machine (TBM), Earth Pressure Balance (EPB), Open Face Shield (OFS), and New Austrian Tunneling Method (NATM). Cut & Cover was used for selected areas of single, double, and triple track configurations. In the majority of cases, the tunneling was within an average depth of 20 m. Softer areas required NATM, a slower process, but better suited for shallower points under weak structures. In the NATM excavations, narrow tun- nels were carved out and supported with metal arches and shotcrete applications. The tunnels were broadened with specialized machinery; then a wa- terproofing membrane was laid along with a perma- nent concrete lining. At deeper locations with stable soil, computer- operated, hydraulic TBMs were utilized. These ma- chines had a 9.5-m diameter with a full-face cutter head. The TBMs were designed to bore through the 9
hardest ground at depths ranging from 8 to 28 m below the surface. Rotating cutter heads, fitted with excavating bits and disk rollers, broke up the rock and soil. Conveyor belts removed the debris. Immediately after each forward push, eight precast concrete segments were installed around the perime- ter of the tunnel to form a closed ring, leaving be- hind a nearly completed tube. Afterwards, grout in- jection was used to fill gaps in the soil and form the final walls of the tunnel. For the Line 2 project, tunnel production was in three phases: ⢠Early period (June 1994 to July 1995): 1.4 m/day ⢠Archaeological Study Phase (July 1995 to June 1997): 0.4 m/day ⢠Final Production Period (June 1997 to January 1999): 8.4 m/day For the extension project, EPBs were used for tunneling. These machines have a 9.5-m diameter with full-face cutter heads. Cut and Cover methods were used almost exclusively for station construc- tion. However, NATM was used for five stations that had limited street availability. Monitoring was performed throughout the con- struction of the metro system. Extensive instrumen- tation was used to monitor the behavior of both the adjacent buildings and the construction sites. Vertical and horizontal displacements were recorded. Appropriate actions were taken when re- quired to address local deformations. In 1999, Athens experienced an earthquake that registered 6.2 on the Richter scale. Accelerations of the earthquake up to 0.6 g were recorded in a local- ized area due to abnormalities in the ground. No tun- nels suffered any damage, even though they were designed for 0.16 g. Naples The city of Naples occupies land with a particu- larly variegated morphology attributed to the vol- canic nature of the region. The subsoil beneath the city primarily comprises pyroclastic material, such as ashes, lapillus, cinders, pumice, pozzolana, and tufa. Because yellow tufa is a very common soft rock in the region, its presence played a major role in determining the construction methods used to build the alignment and stations. The soils overlying the tufa formation are loose cohesionless materials, while the tufa itself is gen- erally a soft rock with low permeability, 10.4 to 10.5 cm/s. Throughout the urban area, the tufa rock is permeated by an intricate system of caverns. Prior to the tunnel mining excavations, these caverns were carefully filled with cement grout. The area also has a relatively shallow water table. The alignment for Line 1 is characterized by rel- atively deep tunnels, which are located within the base formation of the tufa. The top of this formation is found at depths below the ground level ranging from 15 m at the Dante station to 32 m at the Toledo station. Except for a short stretch near the Dante sta- tion, the tunnels are below the water table. The line consists of two circular tunnels with an inner diameter of 5.85 m and an excavation diame- ter of 6.75 m. The tracks are generally parallel, with a center distance between tunnels of 11 m. The tun- nels are being excavated by a pressurized shield using the EPB approach. The platform tunnels, with an outer diameter of 10.9 m, will be excavated by traditional means after improvements to, and water- proofing of, the surrounding soil. The tunnels are given a lining, which is formed by using prefabricated concrete segments that are in- stalled inside the shield and then sealed against the soil by extruded concrete. The lining is made water- tight by gaskets, housed along the whole perimeter of the lining segments, and then tightened with spe- cial bolts. In the stretches above the water table, a shield that performs open-faced advance tunneling is used. In addition, steep grades and stations deep below the surface have become a necessary design feature of Line 1. Several areas of the system have required grades as steep as 5.5%. Construction of five planned stations requires 20 à 45 m excavations at depths between 35 and 55 m. The lower stretch of the Line 1 subway is at present under construction; archaeological studies are currently proceeding at the open cut stations (see Figure 4). Because of the shallow water table in Naples, the effects of possible subsidence are monitored con- stantly. Systematic monitoring is carried out during construction, with vertical and horizontal move- ments monitored at strategic points at both grade and below-grade levels and at cross-sectional areas of the tunnels and station wells. 10
Rome The central core of the underground segment of Romeâs Line C will be constructed using two 10-m- diameter TBMs to minimize impacts to sensitive historic areas and reduce congestion resulting from construction. The twin 10-m-diameter tunnel sec- tions will be constructed with a centerline distance between tunnels that generally ranges from 24 to 33 m and is as wide as 42 m. The crossing at the Tiber River will have a centerline distance of 33 m. It will be approximately 127 m deep with the top elevation of the tunnels set at approximately 10.8 m below normal water elevation. Open cuts will be necessary for the central core stations to allow for the neces- sary archaeological studies. Planners expect that the archaeological study zone will be more than 8 m thick. Gallery spaces above the platform are excavated by cut and cover. The construction of gallery levels and entrance corridors above the platform adds flex- ibility in placement and size in relation to platform spaces because the platform level is evacuated by a larger boring machine. Entry/exit corridors are built from these gallery levels, with extreme sensitivity to archaeological considerations and historical monu- ments above. Geological studies, in conjunction with subsi- dence studies, have determined that due to volcanic fissures and a 10-m upper zone of geological voids, the central core segment will require extensive back- fill. A bore hole monitoring program is also needed to confirm the proper backfilling of voids. An ex- tensive grout injection program has also become one of the major factors in higher than expected con- struction costs for the central core segment. The middle underground segment will be con- structed using four 6-m-diameter TBMs. This seg- ment is characterized by previous excavations that must be addressed to avoid future subsidence con- cerns. Engineers have utilized camera technology to assess the areas that need to be backfilled. A major concern with the construction of Line C is the possible detrimental effect of vibrations on an- cient monuments. Local universities have provided extensive monitoring of existing buildings to review current levels of vibration. The universities used computer model analysis to establish behavior of ad- jacent buildings, verification of behavior on existing building cracks during tunnel excavation, and in- vestigation of subsidence both transverse and longi- tudinal to the tunnel alignment. In particular, using the computer-aided Finite Element method, stress analysis was performed on an existing basilica to de- termine whether the tunnel excavation would ad- versely impact the church. It was determined that tension stress was very low and well within the ap- propriate accepted tolerance levels. The summary of the studies indicated that the underground vibration levels will be well below the ambient levels that cur- rently exist for street level traffic. Therefore, the de- signers set the vibration criteria at 2 mm/sec. To fur- ther minimize the effects of vibration, the agency has specified special trackway designs that employ a floating bed concept with rubberized dampening (see Figure 5). Milan Milanâs subsoil includes sands and clays in the upper layers. The subgrade water elevation changed throughout the construction period. This change re- quired adjustments to the construction methods em- ployed for tunnel excavation. Traditional boring log investigation was performed to establish design pa- rameters and construction requirements. Archaeology Athens The archaeological excavations in Athens are a joint venture of AM, the construction contractors, and the Ministry of Culture (MoC). The MoC has the responsibility for supervising all archaeological activities. Trained archaeologists oversee each proj- 11 Figure 4 Station open cut in Naples.
ect from start to finish. This includes the design of the project, the safeguarding and exhibition of any objects found, and the publication of reports docu- menting the excavations. The transit agency pro- vides funding and coordinates the archaeological ac- tivities with other phases of the construction project. Before soil was turned, engineers with the MoC determined which points along the planned subway routes were likely to be declared archaeologically significant. While historians searched for clues using the ancient writings of Herodotus, engineers used georadar, a process that records underground images by sending energy into the earth and inter- preting reflections. By using both these methods, ancient sites were located. Approximately 70,000 sq m have been exca- vated (see Figure 6), unearthing more than 50,000 archaeological findings dating from the Neolithic period to the modern era. Discoveries include pub- lic baths, cisterns, ancient roads, city walls, drains, cemeteries, tombstones, statues, and pots and other household items. For example, an ancient aqueduct was discovered; it has been rebuilt by archaeologists for display at the Monastiraki station. Priority was given to preserving the antiquities over maintaining the original plans of the construc- tion project and its schedule. For example, in the early phase of constructing a new station, 700 graves were found. Instead of trying to excavate that area, the construction of the station was stopped and the line rerouted. Further, it took 11 years to build the Monastiraki station because of the location of a Byzantine church. One station and adjacent tunnels were deleted from the scope of the project due to archaeological risks. In addition, the Akropoli, Monastiraki, and Panepistimio stations were built using tunneling methods instead of the traditional surface excavation because these stations are located in the heart of the ancient Greek civilization. Over the course of building the base project, the archaeo- logical delays slowed construction by 2 years. Naples In Naples, archaeological surveys are conducted before any construction begins. The team visited two excavation sites in Naples. At the first site, Municipio, excavations are being conducted 3 m below sea level. At this site, special pipes were used to draw water out before the excavation could begin. After draining this site, archaeologists discovered many preserved artifacts. When antiquities are located at the Municipio site, archaeologists work in two shifts, from 6:00 a.m. to 10:00 p.m., to clean, number, catalog and if possible, restore the items. In the last year, 13 m have been excavated. The amount of time it takes to conduct the excavations depends on the number of artifacts found. Artifacts, dating from the 4th cen- tury B.C. to the 10th century A.D. have been dis- covered. In addition to these discoveries, historians have learned that the coastline was once much far- ther inland than it is now. 12 Figure 5 Romeâs rail configuration for vibration mitigation. Figure 6 An excavation site in Athens.
