LRT1 MANILA - ONE LAUNCHER PROGRESS IN THE CITY 1 1- Launcher above a river. 1- Launcher above a river. the existing line lrt1 and its southern extension © BOUYGUES TP TECHNICAL DIRECTOR, BOUYGUES TRAVAUX PUBLICS - RONAN CHESNEL, RESEARCH MANAGER, SYSTRA AUTHORS: DOMINIQUE DRONIOU, PROJECT DIRECTOR, BOUYGUES TRAVAUX PUBLICS - FRANKLIN GEDALOF, WORKS N° 970 JULY / AUGUST 2021 INTER iconic. The thoughts of all who knew him are with his wife Catherine and his two sons Mathieu and Baptiste. Dominique passed away on July 15. He will remain in our memories as a colleague and friend endowed with great human and managerial qualities developed throughout his 39- year career within the Bouygues Construction group. He has participated in many projects This article, of which he is co- author, as well as the photo on the cover of the issue, are dedicated to Dominique Droniou, Director of the LRT1 Manila project. The existing Manila LRT1 line Difficulties in acquiring the land by the Philippine government led the concessionaire to propose the construction of the first 6.6 kilometers of this extension comprising 5 stations (figure 3). (Light Rail Transit), the first line of this type commissioned in Asia (1984), currently consists of 20 stations and an overhead structure of around 20 km supporting light rail rolling stock powered by catenary. Its alignment crosses Metro Manila from north to south and serves the cities of Quezon City, Manila and Pasay. The line has correspondences with the two other lines in service of the metropolis LRT2 and MRT3. In February 2016, the concessionaire Lrmc (Light Rail Manila Corporation) Manila, the economic heart of the country where nearly 16 million inhabitants live, currently only has 3 metro lines in operation for an average daily number of 1,550,000 passengers. Many extension projects or construction of new lines are currently underway to significantly increase the transport capacity of this gigantic agglomeration. chooses the Bouygues Travaux consortium Cavite passing in particular through the towns of Parañaque and Las Pinas. This extension also makes it possible to reach the Ninoy Aquino international airport and the PITX bus station (Parañaque Integrated Terminal Exchange) which serves the provinces south of the Manila agglomeration. Public - Alstom for the construction of the southern extension of this line comprising 12 km of additional tracks as well as 8 stations to link the existing line to the province of NATIONAL THE SOUTHERN EXTENSION OF THE LRT1 LINE INTO MANILA IS PART OF THE NATIONAL INFRASTRUCTURE CONSTRUCTION PROGRAM LAUNCHED BY THE PHILIPPINE GOVERNMENT IN 2017 ACROSS THE COUNTRY. IT IS ENTIRELY AERIAL ON 6.6 km AND HAS 5 NEW STATIONS. THIS LINE IS INSERTED IN AN EXTREMELY DENSE URBAN AREA, HAS MULTIPLE INTERFACES WITH EXISTING NETWORKS AND THIRD PARTIES AND CAN ONLY USE A 10m WIDE WORKS AREA ONLY ALONG THE ALIGNMENT. THESE CONSTRAINTS HAVE COMPLETELY ORIENTATED THE STRATEGIC CHOICES OF METHODS OF CONSTRUCTION AND DESIGN. 62 Machine Translated by Google 2 2- A launcher in an urban area. 2- Launcher in urban area. 3- Alignment of phase I of the Cavite Extension LRT1 project. 3- Alignment of phase I of the LRT1 Ca vite Extension project. 3 JULY / AUGUST 2021 WORKS NO. 970 63 © BOUYGUES TP The original design, carried out in 2013 during the tender phase, consisted of 2 prefabricated U- shaped viaducts and installed by entire span (1 lane supported by 1 U- shaped viaduct) offering definite advantages in terms of urban integration and costs. When the works team arrived on site in 2017, this design was reviewed following a reassessment of the site constraints: à The length of the spans is also re- examined in order to reduce the total number of supports while respecting the constraints linked to the installation and commissioning of the structure. à The objective of reducing the time and number of installation cycles in order to à Along the alignment, the construction zone is now limited to 10 m in width. It is therefore necessary to favor a design with a single deck supporting 2 lanes in order to reduce the total width of the structure. limiting interfaces with third parties is essential. Power lines are found all along the alignment. One of the airport runways is located less than 300 m from the project. 1 km of the alignment is above the Parañaque River (Figure 1). The quantity and duration of work carried out on site must be kept to a minimum in order to disturb third parties as little as possible and reduce the risk of incidents during the work (figure 2). a revised solution site constraints taking into account the news Machine Translated by Google FUNCTIONAL CUT The foundations © BOUYGUES TP 64 MONOPILE AND BEARING CAPACITY INTER à Straight webs and an upper slab that can be curved in order to follow the alignment, including in particular sections with minimum radii of 103 m and making it possible to remain within the imposed width of 10 m. less seismic forces compared to a multi- pile solution. This solution also makes it possible to speed up the construction cycle and limit the safety problems inherent in the construction of piles, particularly in the Parañaque River. However, it requires an increased quality approach in the construction of the foundations due, in particular, to the lack of redundancy of the structure. This overhaul of the design and construction methods is accompanied by substantial work to identify interfaces with third parties and networks and the setting up of regular technical meetings with the client and the various stakeholders to define the prerequisites for completion. Works. à An "open" section compared to a conventional box in order to reduce the weight of the spans and facilitate the prefabrication cycle, in particular the stripping of the spans. à A single deck carrying 2 lanes and prefabricated per entire span. à Typical supports consisting of circular piles with a diameter of 1900 or 2500 mm on monopiles with a diameter of 2500 mm or 2600 mm. The monopile solution has the double advantage of minimizing the in situ working space and the construction cycle and of providing sufficient flexibility so as not to attract excessive seismic forces, the project being located in the immediate vicinity of an active seismic fault. The solution finally adopted is therefore a deck in the form of a PI (figure 5): à Spans of variable length from 23 m to 34 m, prestressed by pre- tensioning for a maximum weight of 400 t and placed using a launcher (figure 4). Given the characteristics of the project, in particular the high seismic demand, foundations made up of monopiles 2.5 or 2.6 m in diameter were adopted. Within the limit of acceptable displacements, the use of the monopile makes it possible to have a sufficiently flexible structure attracting NATIONAL WORKS N° 970 JULY / AUGUST 2021 4- A launcher advances in the city. 4 5 5- Functional section. 5- Functional cross section. 4- A pitcher progresses in the city. Machine Translated by Google When constructing most piles, permanent or temporary steel casings 16 mm thick As a safety measure, due to the non- redundancy of the monopile system, an additional safety margin 80 t capacity caterpillar for installing casings (temporary or permanent) as well as installing and butting the reinforcement cages, and a polymer plant to support the excavation before concreting (figure 6). The main challenge related to the geotechnical design of the piles is the definition and identification of the level of the Gua dalupe tuff, the main resistant layer of the project. The GTF (Guadalupe Tuff Formation), corresponds to volcanic tuffs and sedimentary rocks, stratified horizontally with individual soil layers not exceeding 6 m in thickness and granulometry varying from clays to sandstones. are installed before excavation. They maintain the soil during excavation, installation of reinforcement cages and concreting for the softest layers. The sequence begins with the placement of the casing (the length of which depends on the geotechnical site conditions) using a vibrating hammer. The site counted up to 5 pile workshops working simultaneously on the alignment. Each workshop consists of a rotary drill (Kelly type) for excavation, a crane on The piles are founded in the GTF over a minimum length of two to three times their diameter. The GTF was defined by a geotechnical campaign with drilling 30 to 40 m deep, carried out at each pile. For each borehole, SPT, coring and laboratory tests (particle size distribution, Atterberg limits, resistance tests) were carried out. 20% on the bearing capacity was considered, in accordance with project standards. The excavation is done in two stages and begins with a pilot hole with a diameter smaller than the final diameter in order to begin to destructure the ground within the pile (and facilitate the excavation of the final diameter). This also makes it possible to carry out a soil analysis in order to verify that the conditions remain close to the stratigraphy taken into account in the design. During the final excavation, the polymer is pumped into the hole to ensure its stability. After having filtered the polymer, one then proceeds to the installation of the cage of reinforcement by sections of 15 m; the splicing between sections is done by means of couplers while the lower part of the reinforcement cage is suspended from the casing driven into the ground. A 300 mm diameter hopper which remains submerged throughout the operation is use This additional geotechnical campaign revealed significant variations in the fracturing conditions of the GTF. Given this uncertainty, the validations of the bearing capacity and the length of the piles were subjected to an additional verification process by means of dynamic load tests (PDA). Out of 231 piles to be built, 12 PDA tests (5%) were recommended based on the analysis of the variability of the geotechnical conditions encountered. 6- Foundation equipment. 7- Provisional jetty. 7 6 7- Temporary jetty. 6- Foundation workshop. CONSTRUCTION JULY / AUGUST 2021 WORKS N° 970 65 © BOUYGUES TP Machine Translated by Google Before being set up in the final position, each Pi is equipped with all of its pot bearings by bolting them to the upper plate. Pot bearings have been adopted and support the static loads of the deck as well as the seismic forces The upper plate of the pot bearings is embedded in the Pi during its pre- production. The height of the connection studs of this plate in the Pi is limited to 100 mm to avoid any interference with the prestressing strands located in the heel of the webs. level 1 as well as the level 2 seismic uplift forces (the other forces due to the level 2 earthquake being supported by the shear key). In order to speed up construction, partially prefabricated headers The shape of the shear keys corresponds to the reservation left in the diaphragm of the Pi. The 231 columns of the project are made using 15 different sets of formwork, the sizes and diameters of which can be adapted to all diameter and height scenarios encountered on the alignment. The sequence begins with the installation of the pile reinforcement cage followed by the installation of the drainage pipe (integrated inside the pile). A 500 mm high kicker is then concreted which allows the correct and precise positioning of the formwork for the pouring of the column at once over its entire height. The works of the project are classified as essential. 2 levels of earthquake must be considered: At the head of the header is also installed a shear key, implemented to resist seismic forces (retaining the deck) and poured with the second phase concrete of the header. The connection of the longitudinal reinforcement between the pier and the pile is ensured by couplers placed at the pile head. Circular piles of 1.9 or 2.5 m in diameter were implemented on the project, with heights varying from 0.5 to 8.7 m. The piles are cast in place. It was therefore necessary to carry out a specific seismic study to determine the specific seismic acceleration spectra to be taken into account for the studies. have been put in place. A precast concrete shell is made at the precast site. The shell is then transported to the construction site (figure 9), placed by crane and supported by temporary supports anchored in the pile and equipped with screw jacks for vertical adjustment (figure 8). The prefabricated shell, playing the role of formwork, is then concreted after placing the necessary railing iron. The project is located within 10 km of the active Marikina Valley Fault. For the 1 km long section located above the Parañaque River, a temporary metal jetty is built and is used for the realization of the piles but also the piles and the headers (figure 7). Its demolition after the end of its use and once the superstructure has been completed is one of the last challenges to be met by the production teams in charge of the construction of the bridge. The transfer of the load to the final position is then carried out after the end of the installation cycle of each Pi, including its adjustment in its final position and the casting of the lower support blocks on the header. 9- Lifting the prefabricated headers. 9- Lifting pre- fabricated pier caps. 8- Installation of prefabricated headers in the river. 9 8- Placing pre- fabricated pier caps in river. 8 WORKS N° 970 JULY / AUGUST 2021 © BOUYGUES TP © BOUYGUES TP CONSTRUCTION METHODS POT SUPPORTS, CHARACTER PIERS AND HEADBOARDS, MAIN CHARACTERISTICS AND METHODS OF CONSTRUCTION SPECIFICATIONS MAIN RISKS AND THE MARIKINA VALLEY FAULT INTER 66 focus on design the piles, trimmers and pious pier seismic and supports NATIONAL Machine Translated by Google For type 1, an elastic design is considered, the presence of a plastic hinge in the ground not being acceptable if not approved by the customer. at Level 2: the structure has a low probability of collapse but can accept significant damage with possible interruption of operation. Partial or total replacement of the structure may be required after an earthquake. to Level 1: low to moderate seismic risk with a return period of 100 years. Type 2, ductile design, is the most used on the project. Type 1 is considered when the forces applied to the piers are too great for a diameter of 1.9 m. to Level 2: high seismic risk with a return period of 1000 years. It was therefore not considered possible to adopt a ductile approach for this configuration. at Level 1: the work remains in the elastic range without damage or with minor damage which The standard approach for type 2 is to consider a ductile design for the pile with behavior coefficient. These earthquake levels, considered in terms of horizontal and vertical acceleration, have the following objectives: The seismic design is carried out according to the AASHTO LRFD 2012. The plastic ball joint is placed at the base of the pile. can be repaired easily. For some cases, when the pier- pile system is quite flexible (high piers and/ or deep piles (low GTF level)), it is more economical to consider an elastic design (without behavior coefficient). This is due to the fact that the reduction of the forces - and therefore of the quantities - in the pile which could be brought about by the use of a behavior coefficient does not substantially compensate for the additional reinforcement necessary in the pile to ensure a design overcapacity. 3 typical configurations are considered (figure 10): 10- Seismic design configuration for piers and piles. 11- Precasting and storage area. 11- Prefabrication and storage area. 12- Rebar cage being lifted. 12- Reinforcement cage being lifted. 12 13- Enclosing formwork under going installation. 13 13- Closing formwork being installed. 10 11 10- Seismic design configuration for piers and piles. SEISMIC DESIGN OF PILES AND PILES © BOUYGUES TP © BOUYGUES TP JULY / AUGUST 2021 WORKS NO. 970 67 © SYSTRA © BOUYGUES TP SEISMIC DESIGN CONFIGURATION FOR PILES AND PILES Machine Translated by Google NATIONAL PRE- TENSION BENCH WORKS N° 970 JULY / AUGUST 2021 a shaped apron of pi posed to the launcher by whole spans 14- Pre- tension bench. 14- Pre- tensioning bench. 15- Pi Drill system. 15 15- Pi Drill system. 14 PREFABRICATION INTER 68 à Reduced width: cross section with a maximum width of 8900 mm which falls within the limits of the project by 10 m. The typical width in straight alignment is 8.13 m. to Maximum weight: 400 t. with straight webs and curved upper slab: the Pi can be adapted to both straight spans and curved spans up to 103 m in radius. The webs remain straight, as does the preload inside the web heels, while The minimum span length on the project is 23 m. à Span length: maximum span length of 34 m in order to minimize the number of foundations. that the radii imposed by the alignment are managed with a curved upper slab. by entire span and erection by launching beam. The spans are prestressed by pre- tensioning (T15S strands) in the longitudinal direction. Full- span laying at the launcher minimizes the interface with traffic on the roads crossed by the alignment. à Erection by entire span: this solution allows rapid construction with prefabrication The non- linear effects that affect the stiffness of piers and piles, such as inelastic deformations, have been considered by taking into account reduced inertias. A range calculation was also carried out for the soil stiffness (-50%/ +50%) in order to take into account the possible variability of the geotechnical data considered as well as the non- redundancy of the monopile system. For each module, 4 additional spans on either side have been modeled to take edge effects into account. à Open section: as its name suggests, the cross section resembles the Greek letter ÿ. It is an open section which consists of two webs and an upper slab. Diaphragms are placed at each end of the span. Compared to a conventional box girder, the Pi shape, having no lower slab, facilitates demolding operations and minimizes the weight of each span. The 32,000 m2 are divided between a hangar used for the prefabrication of the spans and a storage area for the already cast Pis (figure 11). Space is also available for prefabrication and storage of prefabricated pile heads. In the hangar, two benches on my floor are mounted in parallel for the entire Pi construction cycle. The determination of the forces considered in the structural verification of the piers and piles was made from a multimodal analysis (the project was divided into several modules). KEY FEATURES The Pi has the following features and benefits: The prefabrication area located at the southern end of the alignment is the heart of the LRT1 site. Machine Translated by Google 16- First Pi Girder. 16- First Pi Girder. 17- Carriers on the road for the launcher. 17 17- Carriers en route to the launcher. 16 JULY / AUGUST 2021 WORKS NO. 970 69 At the upper level of the formwork, prefabricated peripheral concrete walls make it possible to create the straight or curved shapes of the upper slab. tion, angle of the diaphragms variable. During tensioning, 8 load cells make it possible to follow the evolution of the prestressing from the tensioning to the relaxation of the cables once the concrete has set. the finishing work of the reinforcement and adjustment of the formwork are in progress. The cables are manually inserted through the reinforcement cage while Each Pi contains between 25 strands (straight spans of 23 m) and 54 strands (curved spans R103 of 32 m) per core, with a section of 15.7mm (Ap=150mm2 ). Initial tensioning is done with a single jack, then all the strands of each heel are tensioned simultaneously using 1450 t jacks. a metal frame embedded in the concrete allows the recovery of the forces during tensioning. On the mobile side, 2 cylinders with a capacity of 1450 t pull on a carriage where the strands are fixed by means of keys, and rest on the metal frame. On the fixed side, the strands are connected directly to the metal frame, always with wedges. Since April 2021, an additional operation has been added at the end of the prefabrication cycle in order to prepare the track works. The track is supported by concrete stringers which are made in situ by Alstom teams, once the deck has been laid. The connection with the deck is made by means of steels operating in shear distributed along the tracks; holes in the deck are now made using robots mounted on a platform circulating along the formwork (figure 15). straight, curved or transi spans At the front of the hangar, two main forms are used for pouring the Pis after placing the reinforcement cage using overhead cranes (figure 12). Each formwork is made up of an external formwork 36 m long, several adjustable internal formwork modules and 2 partition formwork at the ends (figure 13) to achieve all the configurations encountered on the alignment: For each span, the total assembly of a reinforcement cage takes about 3 days. The preparation of the formwork, the installation of the reinforcement cage, the installation and tensioning of the prestressing as well as the concreting can be carried out on a 24 hour cycle. The first Pi was cast on July 14, 2020 and at the end of April 2021, almost half of the 203 spans had been completed. At the rear of the hangar, assembly jigs allow the prefabrication of reinforcement cages for the diaphragms and for the webs. Two main jigs allow assembly of the entire cage including the upper slab. Concreting is done in one go and in one direction only. A vibrating rule makes a pass along the span at the end of concreting in order to ensure the V- shape of the upper slab. Around each formwork, the prestressing bench (figure 14) consists of a mobile part and a fixed part allowing the tensioning of the strands located at the level of the 2 lower heels of each Pi. On each side Machine Translated by Google WORKS N° 970 JULY / AUGUST 2021 PI INSTALLATION 19- Excerpt from the kinematics of the launcher: launch of the support beam. 19- Excerpt of launcher kinematic drawing: launching the supporting girder. 18 18- Extract from the kinematics of the launcher: lifting of the span (Pi). 18- Excerpt of launcher kinematic drawing: lifting the span (Pi). 19 INTER EXCERPT FROM THE KINEMATICS OF THE LAUNCHER: LAUNCHING OF THE SUPPORT BEAM EXCERPT FROM THE KINEMATICS OF THE LAUNCHER: LIFTING OF THE SPAN (Pi) 70 NATIONAL The launcher consists of 2 beams (main beam and support beam) which slide longitudinally one above the other and mutually support each other during the various phases of launching and installation of the spans (figures 18 and 19). the rear support on the deck, the mobile supports of the support beam, the lifting winches and the Adele system. Just after placing a span, the main girder can advance to the next pier using the rear support on the deck and after disengaging the fifth wheel which connects the main girder to the support beam. Two conveyors allow the spans to be supplied to the launcher on the deck already built (figure 17). main of the launcher. Each winch is equipped with a lifting beam on which the Adele system is mounted, which engages the Pi at the level of the reserves provided for this purpose. is programmed to operate in tandem and directing instructions for operators are pre- programmed based on the geometric characteristics of the supported Pi. After the formwork has been opened and the cables released and then cut, the Pi is lifted by a pair of carrying trolleys and transferred to the storage area (figure 16). Each trolley has a load capacity of 220 t and is made up of 8 motorized wheels supporting 2 telescopic legs that can operate from 12 to 22 m in height as well as a winch mounted on the crosspiece connecting the 2 legs. The winch is equipped with the Adele system consisting of two hammer locking systems inserted into the reservations of the Pi provided for this purpose. Each transporter consists of a metal frame (taking up the weight of the spans) resting on a group of wheels 2.04 m in diameter and a pilot cabin for the operator. The conveyors have a laden speed of 1 km/ h (4 km/ h unladen) and must remain above the webs of each span with an accuracy of ±300 mm. After supply by the carrier, each Pi is successively lifted by the two winches of the beam All the parameters of each span have been programmed beforehand in order to facilitate the work of the operators. 57 Ft can be stored on a maximum of 3 floors out of the 9,000 m2 of storage area. The carrier trolleys also make it possible to deliver the Pi on the conveyors located on the deck already poured in front of the prefabrication area. Each pair of forklift Then the span is lowered on 4 temporary hydraulic jacks which allow vertical and horizontal adjustment. The transfer to the final supports is done after setting the Pi in its final position and once the launcher has advanced to the next span. The sequence of laying and progression of the launcher involves, during a complex ball, all the elements that constitute it: the main beam, the support beam, the fifth wheel, Machine Translated by Google MAIN QUANTITIES KEY STAKEHOLDERS LRT1 MANILA - LRT1 MANILA - JULY / AUGUST 2021 WORKS N° 970 71 A LAUNCHER ADVANCES IN THE CITY AN AVANZA LANZADOR FOR LA CIUDAD When launching the support beam, its rear part is suspended from one of the winches of the main beam. for project constraints, including radii up to 103 m and slopes of ±3.4% (Figure 20). All the launcher equipment has been sized specifically The first span was installed on September 15, 2020. As of the end of April 2021, 67 spans have been laid, including those in the three- lane Dr Santos area which includes for each span a Pi keyed to a half pi. The support beam advances until it reaches a state of equilibrium with its front nose located beyond the next The installation cycle takes place over 1 day. m The support beam is held by 3 vertically adjustable supports which slide along the beam during the various launching phases. pile. The fifth wheel is then engaged, which makes it possible to vertically adjust the support beam to approach the next pile. After release of the winch and successive movement of the 3 supports along the support beam, the latter reaches its state before installation, supported at the rear and the front on the headers of the span adjacent to that which will be installed during the next cycle. The deck precasting and placing cycles have now been mastered and the bridge will be mostly completed during 2021. m Bouygues Public Works - Alstom consortium (average length 24.9m) (Architecture + Civil Engineering + Fluids and Low Energy) Light Rail Transit Authority (LRTA) • Prestressed quantity: 747 t i.e. a ratio of 24.6 kg/ m3 20- Launcher at the end of Ninoy Aquino Avenue. DEEP FOUNDATIONS: 20 • Quantity of passive reinforcement: 6,303 t, i.e. a ratio of 208 kg/ m3 • Total concrete volume: 7,827 m3 • Rebar quantity: 2,067 t i.e. a ratio of 264 kg/ m3 • Systra for the Civil Engineering part of the Viaduct and all the stations • Total concrete volume: 30,305 m3 • 231 cast- in- place piers for a total length of 1,000 m (average height 4.3 m) DESIGNATE : BATTERIES AND BATTERY HEADS: • 202 precast spans and 4 cast- in- place spans for a total length of 6,647 m • Rebar quantity: 7,693 t i.e. a ratio of 262 kg/ m3 COMPANY (design - construction): APRON : • Total concrete volume: 29,333 m3 INDEPENDENT CONSULTANT: Egis International - Erigphi JV FORMWORK MANUFACTURING: Nineveh (Italy) DEALER: Light Rail Manila Corporation (LRMC) MANUFACTURING OF CARRIERS: Cimolai (Italy) LAUNCHER MANUFACTURING: Deal (Italy) 20- Launcher at the end of Ninoy Aquino Avenue. • 231 bored piles for a total length of 5,750 m FUNDING: Department of Transportation (DOTr) / • Alstom for the system part DOMINIQUE DRONIOU, BOUYGUES PUBLIC WORKS - FRANKLIN GEDALOF, DOMINIQUE DRONIOU, BOUYGUES PUBLIC WORKS - FRANKLIN GEDALOF, BOUYGUES PUBLIC WORKS - RONAN CHESNEL, SYSTRA BOUYGUES PUBLIC WORKS - RONAN CHESNEL, SYSTRA The evaluation of the location restrictions for the construction of the expansion of the LRT1 line has been raised by the Bouygues TP company and the design engineer Systra has proposed a solution to the media that will reduce the maximum risk of construction to the length of a line located in a dense urban area with numerous redes and connection infrastructures. La forma en Pi del viaducto y la colocación de luces enteras, por une parte, y una alineación con severas limitaciones, por otra, han precise el diseño y la construcción de equipos specíficos para el proyecto. Los ciclos de prefabricación e instalación del tablero están actualmente bajo control, y el puente quedará en gran medida finalizado a lo largo de 2021. m An assessment of the site constraints for construction of the extension of the LRT1 Line led the contractor Bouygues TP and its designer Systra to propose a customized solution reducing insofar as possible the construction contingencies along an alignment located in a dense urban area with numerous interfacing networks and infrastructure facilities. Given the Pi shape of the viaduct and the laying of whole spans, as well as the severe alignment constraints, specific equipment had to be designed and built for the project. © BOUYGUES TP ABSTRACT Machine Translated by Google