Work Progress on the Apennine Road Bypass to Highway A1 between Bologna and FlorenceAs part of the upgrading of highway A1 Milan-Naples on its Apennine section between Sasso Marconi (Emilia Romagna) and Barberino di Mugello (Tuscany), Autostrade per l'Italia has to modernise slightly more than 58 kilometres of roadway, half of which in tunnel, to cross a difficult territory characterised by hilly massifs of the Tuscan-Emilian Apennines, narrow valleys crisscrossed by mountain-like streams.The roadbed will carry a minimum of three lanes per direction and a septum of at least four metres. Typically, the lane widths will be 3.5 metres for the passing lane, 3.75 metres for the fast and slow lanes and three metres for the emergency lane. The roadbed in tunnel is planned for two 3.75 m-wide lanes and an emergency lane of identical width, for increased safety. The project has been divided into several contracts, with major tunnelling works. Click here.Contract 2This is a 4.8 km section between Sasso Marconi and La Quercia, including the Monte Mario tunnel (2,280 m for the north tube and 2,225 m for the south tube). The excavated cross section varies from 145 sq m (width of 15 m, height of 10.4 m) to 191 sq m (width of 17.3 m, height of 12 m), with a maximum radius of 10.6 m. There are two vehicular cross passages (50 m in length each, 68 sq m in cross section), four pedestrian cross passages with variable lengths of 35 to 58 m and excavated section of approx. 15 sq m, a pedestrian crosscut with expanded section (about 34 sq m), four 82.1 m-long lay-bys (two in each tunnel), eight type A niches (5.62 m wide) and 18 type B niches (3.62 m wide) to install equipment (4 type A + 9 type B niches in each bore).The builders are CMC, Grassetto and CCC. The north tube broke through on 13th September, 2005. The south tube broke through in October. The section has been delivered on 4th March, 2006 (as stipulated in the contract). Visit www.cmcra.com, www.grassetto.it and www.ccc-acam.itThe geology dates back to the Lower Pliocene (very inconsistent marls and clays) and to the Upper Pliocene (more cohesive sand with sand banks). Excavation from the Bologna side crossed, in the first 700 metres approximately, very thick sands of the Upper Pliocene and subsequently grey-blue clays of the Lower Pliocene.Excavation from the Florence portal took place completely in grey-yellowish clay of the Lower Pliocene period under slight overburden and was characterised by numerous cave-ins in one tunnel and instable conditions. A chimney formed in the north tunnel on 13th December, 2003 (remedial action allowed the resumption of tunnelling on 22nd March, 2004) and the face collapsed in the south tunnel. There were four attacks, predominantly executed with breakers mounted on excavators. The machinery operated by tunnelling crews included two excavators FIAT Hitachi EX 455 L CH equipped with Indeco UP 7000 W breakers silenced with water mist device to combat dust (one at the Bologna side and one at the Florence side), two excavators FIAT Hitachi EX 285 T with retromatic fastener allowing rapid installation of a pincer to install steel ribs (one excavator on each side, which was also used for construction of the inverted arch) and one excavator EX 455 L CH with Miretti converter for flameproof protection (Florence drive). Visit www.fiatkobelco.com, www.indeco-breakers.com and www.miretti.itFrom February to end 2002, drilling and blasting was used at the Bologna drive, with a rented Tamrock three-boom jumbo allowing 3.5 m-long blasts.The support and lining techniques consisted of radial anchor bolting with Super Swellex-type bolts, continuous anchoring threaded bolts with and without expansion, pre-consolidation of the contour with fibreglass valved tubes and with jet-grouting reinforced with steel rods, pre-consolidation of the face with fibreglass tubes injected with cement grout, with jet-grouting reinforced with fibreglass tubes, and with unreinforced jet-grouting in soft ground (sand or gravel) and steel beams supplied by Metal Legno and Castaldo (2 INP 160, 2 INP 200, 2 INP 220, 2 INP 300, spaced every 1 m to 1.5 m). Visit www.rockreinforcement.com, www.metallegno.com and www.castaldospa.itAt the top heading up to mid-height of the steel beams, welded wire fabric has been placed, then shotcrete reinforced with Maccaferri steel fibres (40 kg/cu m) has been sprayed and a double layer of final concrete has been poured (first layer of 45 cm and second layer of 90 cm). The equipment used for shotcreting were three CIFA shotcreting pumps (CSS PAS 307, PAS 307 FE6 and PAS 307 FE6 ST16). Visit www.maccaferri.com and www.cifa.comSpoil was removed by two FIAT Hitachi wheeled loaders (models W270 and W 130) and 4-axle trucks Iveco Eurotrakker and Mercedes Actros 4143. Visit www.iveco.com and www.mercedes-benz.it/industriali/gamma/actros/default.htmContract 3This 4.5 km section includes two twin bored tunnels: Vado (1,137 m) and Allocco (1,730 m). Work commenced in July 2003 (read E-News Weekly 32/2003). The Vado south tunnel holed through on 27th July, 2005. The north tunnel broke through in September 2005. Breakthrough of the south tunnel at Allocco took place in March 2006 and the north tube is expected to follow suit by the end of April. The section is built by Toto Costruzioni and Carena for a contract amount of EUR121.2 million. Visit www.totogroup.it Contract 4The twin bored tunnel within this contract is 180 m long (north roadway) and 218 m long (south roadway). Named Campolungo, the tunnel is situated in Monzuno municipality (Bologna). The cross section area for each tunnel is 160 sq m on average. The excavated width varies from 16.12 to 17.82 metres, according to the section adopted. The excavated height ranges from 10.47 to 11.27 metres. The width of the finished asphalt surfacing in the tunnel is 12 metres.The geology encountered features various consistencies of Loiano sands (soft in the faults to cemented and even sandstone).The methodology adopted for excavation is traditional means with use of excavators and hydraulic breakers. Muck removal is executed by means of wheeled loaders and dumpers. Temporary support is made of twin IPN 220 steel ribs with steel liner plates and 30 cm of shotcrete reinforced with steel fibres (40 kg/cu m).The contract also includes the Gardeletta cut-and-cover tunnel (800 m). Construction was stopped in September 2005 after a financial crisis engulfed contractor Nino Ferrari, while construction was 70% completed. Autostrade per l'Italia has cancelled the contract in December and re-awarded it in February for a residual value of EUR30 million to Impresa (ex Lombardini), Salini-Locatelli and Compagnia Italiana Strade, thereby allowing the resumption of excavation works. The base tunnel portal on the Valico bypass Contracts 5A and 5BThe 10 km-long section crosses a territory characterised by a difficult hilly topography and peculiar setting of the road alignment. This obliged to define bored tunnels with relatively low overburden and cut-and-cover portals, semi-monolithic concrete boxes with box-outs (so-called 'sheds') and full cut-and-cover sections. Lot 5 is subdivided in two contracts.Contract 5A corresponds to a highway section of approx. 7,638 metres that begins in La Quercia at the junction between the new Variante di Valico alignment and the existing roadbed of highway A1 and ends near the south cut-and-cover entry of the Grizzana tunnel. Contract 5A includes three bored tunnels: Quercia - a southbound 332.5 m single tube to Rome, Rioveggio 1 and Grizzana - southbound and northbound twin tunnels, with respective lengths of 347.3 m / 347.4 m and 2,321 m / 2,342.5 m. These tunnels are key structures of the new roadway.The Rioveggio 1 and Grizzana tunnels are being designed with cross passages for pedestrians and vehicles to allow escape and rescue from one tube to the other in case of emergency.There are also two cut-and-cover tunnels in contract 5A: Casino and Rioveggio 2. Both are twin tubes, with respective lengths of 332.2 m (north tunnel) / 353.45 (south tunnel) and 57 m (north tunnel) / 70 m (south tunnel).The design and build contract 5A on subsection La Quercia-Badia Nuova has been awarded in July 2005 to Nino Ferrari, IRA and Maire Lavori for EUR196 million. The section is still in the design stage but is not affected by the financial difficulties that have hit Nino Ferrari. To date, the design is within schedule.Contract 5B corresponds to a highway section of about 2,412 metres starting in Lagaro at the junction between the south entry of the cut-and-cover stretch of the Grizzana tunnel, part of contract 5A, and finishes in the Val di Sambro tunnel at chainage 7+528. Contract 5B encompasses the partial tunnelling of the Val di Sambro highway tunnel, 877 metres in the south tube and 873.2 metres in the north tube.It also includes the construction of a cross passage to allow for the U-turn of snowplough vehicles from the south tunnel to the north tunnel. This crosscut features a section of 75 sq m.The design and construction of contract 5B has been awarded during the summer of 2005 to CMB, CCC, CFM, Electrowatt Infra and Politecnica Ingegneria ed Architectura. Visit www.cmbcarpi.it and www.ewi.chContract 6-7Contract 6-7 represents a length of about 7.5 km. The main civil engineering structures are the Val di Sambro and Sparvo tunnels, the latter having a length of 1,950 m, and the Molino di Setta cut-and-cover (360 m). The length of the Val di Sambro tunnel is 2,900 m, i.e. the length which is not part of contract 5B. Connecting crosscuts between the two tunnels will be provided for pedestrians and vehicles to allow escape and rescue from one tube to the other in case of emergency together with SOS niches and stopping bays. The bids submitted for this contract are still under evaluation. When sealed envelopes containing the financial proposals were opened, the low bid was that of consortium Operae including Baldassini Tognozzi-Pontello, Guerrino Pivato, Salini-Locatelli and Satrel, followed by a bid submitted by a JV of Vianini Lavori, Toto Costruzioni and Profacta.Base tunnel (contract 9-10-11)Section Badia Nuova-Aglio (11.2 km) of the Variante di Valico includes a base tunnel, which indeed is the major challenging component of the highway modernisation. The section also includes the Poggio Civitella tunnel (2 x 250 m) that connects with the base tunnel through an existing viaduct (on the Bologna side). The tunnelled section is about 165 sq m. The average section is 160 sq m. The total length of the base tunnel is about 2 x 8,600 m. There is also a 823 m-long 15 m-diameter access adit to the middle of the alignment and a 400 m cross passage for the turnaround of snow removing vehicles.Along the alignment, other underground structures will be built: 9.5 m-diameter cross passages for vehicles spaced at about every 900 metres, 7 m-diameter cross passages for pedestrians spaced every 300 m on average, 7 m-diameter emergency bays every 900 m and niches every 150 m.The EUR498.5 million contract has been entrusted to consortium Risalto formed by Rizzani de Eccher, Salini Costruttori and Todini. The groundbreaking ceremony took place in February 2004. Todini is the tunnelling contractor. The ventilation and lighting equipment is not part of the contract. Visit www.todini.itThe tunnel route crosses a rock mass that belongs to the Tuscan formation (Monte Cervarola) and the Ligurian formation (scaly clays).The Monte Cervarola unit consists of a basic chain composed of marls, argillite and limestone (blistered schists) followed by a strong chain of peat, mainly arenaceous (Monte Cervarola's sandstone) and gradually changing in the upper part into a second chain of peat characterised by thinner arenaceous-silty strata with abundant pelitic fine fractions (sandstone of the Monte Mondino and Monte Falterona) and therefore mainly marly formations (Suviana marls, Vicchio marls, etc.).The scaly clay is composed of scaly argillite with intercalated marly and calcareous strata, generally thin (decimetric thickness). Inside the formation, there are frequent discontinuous lithoid compounds consisting of grey limestone (referred to as 'palombini') and subsequently ophiolithic green stone. The rock compounds with highest rigidity (limestone more or less marly, ophiolites, etc.) contained within the plastic mass, i.e. the argillite, have shown instability further to the orogenetic deformations and are therefore disarticulated and highly fractured.To tackle the geology, the project managers intend to use drilling and blasting for 50% of the drive and mechanical means for the remainder.Excavation of the two Poggio Civitella tunnels (250 m) is completed and the final formwork is under way. Tunnelling of the turnaround cross passage for snow removing vehicles is nearing end with only 60 metres to go.Excavation of the base tunnel on the Bologna side has commenced. To begin excavation, it has been necessary to ventilate the existing bores to avoid the accumulation of methane gas inside. This task can only be performed (without interfering with the excavation of the base tunnel) by constructing a connection between the two tunnels and activating a complex ventilation system. Stabilization of the slope of the access adit to the base tunnel, thanks to the installation of retaining walls supported with tension-resisting nails, is almost completed. Sub-horizontal consolidation and excavation of the tunnel are expected to begin during week 15.At the Florence side of the main tunnel, the first phases of diaphragm walls are completed. Cut-and-cover stretches, 160 m at each tunnel, are made necessary to confine a 50 m existing geological landslide. At the north tunnel, the first 50 metres of cut-and-cover tunnel is finished and both the vertical and sub-horizontal reinforcements have been performed and tunnelling started at the beginning of week 14.The tunnel class, with respect to the presence of methane gas, requires the employment of flameproof machinery. Even the tunnel ventilation complies with the presence or possible presence of methane. All working phases take place under the continuous monitoring of gas measuring devices.The tunnelling methodology will depend on the ground to be crossed, therefore the excavation means will alternate. In Monte Cervarola sandstone, systematic drilling and blasting will be used. In the scaly clay, the tunnel face will be pre-reinforced with fibreglass pipes injected with grout prior to excavation with a hydraulic breaker. The same machinery as in the Poggio Civitella tunnel will be used at the base tunnel.Tunnelling in the Monte Cervarola rock mass is executed with two Tamrock Axera T12 Data jumbos and four in total will be working. These three-boom underground drill rigs are equipped with flameproof protection. Shotcrete is sprayed with a CIFA CSS PAS 307 pump. There are three shotcreting pumps at the moment (coming from the Poggio Civitella tunnel) and six will be necessary. Visit www.tamrock.sandvik.comIn the scaly clays, excavators Cat 345 BII and Hitachi ZAXS 350 equipped with breakers Rammer G 100 and G 88 are used. The Cat excavators are three while there is one Hitachi and seven will be operated. Visit www.cat.com, www.hitachi-c-m.com and www.rammer.sandvik.comFor tunnel support, bolts, twin IPN 180-220 steel ribs and fibre-reinforced shotcrete have been installed. Other means used are Dieci Pegasus platforms, Atlas Copco compressors, CTM generators, FlaktWoods ventilators and CIFA formwork. Visit www.dieci.com, www.atlascopco.com and www.flaktwoods.comMuck disposal is done by Cat 966GII loaders and Astra HD 7 dumpers. Many other machines are mobilised at the site in addition to the above-mentioned. Click here. Visit www.astraspa.comContract 12This section, which goes from Badia Nuova to Aglio, has a length of 4.5 km for the north carriageway and 3.3 km for the south carriageway. The tunnels are: Bollone 1 (118 m), Bollone 2 (260 m), Bollone 3 (148 m), Buttoli (620 m) and Largnano (720 m). Work at contract 12, like contract 4, was at a standstill due to the financial crisis that shook Nino Ferrari while progress had reached 5-10%. The contract has been re-awarded to Baldassini Tognozzi-Pontello for EUR128 million. Visit www.baldassinitognozzi.itContract 13Contract 13 between Aglio and Barberino di Mugello is 6.1 km in length. The contract is for the construction of a new southbound three-lane one-way carriageway and the use of the northbound roadway in a single direction to the north. There will be three tunnels: Puliana (1,353 m), Alteta (240 m) and Poggio Manganaccia (2,037 m). Bids are being assessed. Read E-News Weekly 37/2005. ConclusionContract 4 is behind schedule, which will delay the opening to three-lane traffic of the entire section Sasso Marconi-La Quercia in June, as initially scheduled. The first two contracts will be ready in June, contract 3 in August while contract 4 will be delivered in two phases: a first roadway will open in August for two-way traffic with two lanes per direction and by the year end, the two carriageways will be opened.The Variante di Valico between La Quercia and Aglio (32 kilometres including the 8.6 km base tunnel) will only be fully opened when the last contract is completed. The scheme was first programmed for completion in December 2004, then slipped to December 2007 but now full opening is hoped for 2010 according to the latest predictions. The delays will depend on the difficulties at the worksite of the base tunnel and on the executive design of contract 6-7 which needs to be finalised.Opening of section Aglio-Barberino di Mugello is also programmed for 2010 while no date has been set for section Barberino di Mugello-North Florence until the environment impact assessment phase opens. Click it/21. Visit www.autostrade.it and www.osservatoriovariantedivalico.it 16/06.