Draft:Telecabina Bușteni-Babele
The Bușteni-Babele cable car is an aerial tramway in Romania which spans between the town of Bușteni and the Bucegi plateau. It is the main access method for tourists that want to get to the Babele rock formation, the Crucea Eroilor Neamului (Caraiman Cross) or the Omu Peak. This is the longest reversible aerial tramway in one segment if Europe, being 4.35 km long.
Practical information
Technical data
- Engineering: CERETTI & TANFANI Milano
- Executant: M.M.P.G. București (The Minister of Mines, Petrol and Geology) trough T.C.M.M (Trust de Constructii Montaje Miniere) Șantier Brașov.
- Route length: 4350 m
- Altitude difference: 1235 m
- The Bușteni station altitude: 880 m
- The Babele station altitude: 2290 m
- Number of cabins: 2
- Cabin capacity: 24+1 persons (maximum 26+1 if there are kids younger than 14 years old)
- Transport duration: 12-13 minutes
- Maximum speed: 10 m/s or 10*3,6=36 km/h
- Average total speed: 5,73 m/s or 5,73*3,6=20,7 km/h
- Maximum wind speeds that the cable car can operate in: 16 m/s or 16*3,6=57,6 km/h
- Track rope diameter: 40 mm
- Haul rope diameter: 25 mm
- Distance between towers 6 and 5: 400 m
- Distance between towers 5 and 4: 1520 m
- Distance between towers 4 and 3: 530 m
- Distance between towers 3 and 2: 1540 m
Starting the technical project
Romania, being in the stage of socio-multi-national development during the time of the then new president of Romania (Socialist), Nicolae Ceaușescu, wanted to develop the tourism side. As in that period (the 60s - 70s) the expansion and establishment of a large-scale national tourism was desired, the Minister of Tourism at that time, Ion Cozma, initiated a series of projects that had the role of revitalizing national tourism and bringing it up to standards the other countries.
Thus, in the summer of 1970, various meetings took place between Romanian specialists and the Italian government, which, through the Italian company CERETTI e TANFANI, renowned in cable construction technology, offered a technical package for the development of cable installations in the mountain resorts of Romania. Being hired to do the pre-feasibility and feasibility studies of the area where the Bușteni-Babele cable car would be located, this company finalizes all the technical plans, design details and related projects (electrical installations and mechanical part).
Site preparation
The Minister of Tourism from the period 1965-1972 established in 1966, especially within the Faculty of Forestry Brașov Archived 2011-09-12 at the Wayback Machine, the Chair of Forestry where he studied, among other fields: the Forest Funicular discipline. This discipline had the role of preparing specialists to work as construction engineers or designers for the future cable installations that were to be built (Sinaia-Cota 1400 cable car; Cota 1400-Cota 2000 cable car; Tâmpa Brașov cable car; Kanzel Poiana Brașov cable car; Bâlea Cascada cable car -Bâlea-Lac; Babele-Peştera cable car). Through the Romanian-Italian partnership, the Ministry of Tourism of the years 1965-1970 offered the Faculty of Forestry in Brașov, through specialist references, special courses in special metal constructions in the field of cable transport and thus in 1968 several students graduated who would later become involved as specialists in their turn in the design or execution of special works.
Among the young engineers who followed this specialization are Mr. Eng. Mărgărit (currently retired, former chief engineer at S.C. Teleferic SA Prahova - Sinaia cable car) who is appointed site engineer for the new construction of the Busteni-Babele cable car that was to begin in 1973.
Beginning of site works
Being a large-scale and long-lasting construction, the organization of the site involved the detachment and collaboration of 3 teams of workers. The first team would work on the Babele station, the second team on the metal structure and the foundation part of the towers and the third team on the base station.
The actual works begin in the spring of 1973, where the tools specific to mining works are brought: bulldozers, excavators, dump trucks, labor (rescue workers, teams of the Forestry Directorate to arrange the route of the future cable car), cranes, manual and electric winches, etc. Once the site teams are established, the crew move on to the actual construction.
First tower
The work on the first pillar of the cable car started, as is natural for any construction, with the infrastructure, that is, with the part of the foundations and the technology of specific foundation works. According to the technical indications in the project drawn up by the Italian company, the dimensions of the foundations had to ensure the general stability of the structure and all static or mobile forces to be taken over by the foundation (which has dimensions of 3.00m x 2.50m and an embedment depth of 2 m, without the visible part emerging from the ground level).
The technology of executing the infrastructure part is worth a little analysis. There was a forest road that went up a little above the cottage that can be seen under the Bușteni cable car line, and which was used by the dump trucks that came with fresh concrete. The technical norms of the quality of the foundation concrete (concrete brand B400 or C25/30) assumed that during casting the continuity of the volume of concrete in the foundation should be ensured, under no circumstances was casting in stages accepted, therefore the conditions of a continuous castings. For this, the construction site was organized in such a way that the concrete for casting had to be provided all the time. A small mining funicular was installed, similar to the one for coals at the base of that forest road which was then set up for the dump trucks to come and pour the fresh concrete into the mining funicular bucket.
A manual winch was provided to pull that tub full of concrete, the team had people who worked day and night in shifts, and the lighting of the construction site was made of Logs. A 12 mm thick cable was used to ensure the transport of the tub, which was anchored near the construction site at the base of the pillar. Of course, the rectangular foundations also contained the indispensable longitudinal and transverse reinforcements, practically as a network of interlocking bars (diameters of PC52 ø12-14 mm). For safety, some beilageres (bearing systems that allowed a tolerance of 20 cm, necessary for the exact positioning of the base plate of the foundation) were arranged in the middle of the foundations, through which it was slid for the perfect alignment of the base plate of the foundations. In metal constructions, tolerances are of the order of millimeters, so tolerances greater than 5 mm are not accepted!
After pouring the concrete in the foundations and aligning according to the technical drawings, it was time to fix the base plate. The base plate of a metal foundation has the role of receiving and transmitting the pressure forces exerted on the structure, the foundation (embedded reinforcements and anchor bolts). The minimum length of the anchor bolts extended in the foundation, the dimensions and the position of the anchor bolts are established according to the capable bending moment of the column
The anchor bolts are bent at the lower end which in this case, were fixed to those beilagers in the foundation. From a technical point of view, foundations are monolithically cast isolated foundations. After fixing the base plates and embedding them through the anchor bolts in the foundation, followed the part of the execution of the superstructure, the metal structure. The metal structure was made in the factory halls of the Reșița Steel Works. After all the components were checked according to the project, they were painted, specially treated and for testing their joints, the side facades of the metal structure were assembled there, in the halls of the metallurgical plant, and then, disassembled and sent to the construction site in Bușteni.
From a static point of view, the metal structure is a spatial structure made of lattice beams[1]. Like any space metal structure, the overall stability must be ensured by horizontal and vertical bracing and stiffeners. The resistance sections (legs of the column) are formed by bars composed of angle steel profiles with equal wings L 100x100x8, arranged symmetrically along the axis of inertia y-y (see image). To understand a little bit about this system composed of bars, we need to go a little bit into the theory of Strength of Materials. In any material there are longitudinal stresses (called SIGMA stresses) and tangential stresses (called TAU stresses). These bars are checked for tensile forces () and to bending or torsional forces or both (). The logic for choosing angle steel profiles with equal wings lies in another geometric characteristic of the sections, namely the Moment of Inertia, denoted by a large I. Other types of profiles for the metal posts could be chosen, e.g. profiles U or UPN, UPC, Z, etc., but at that time it was considered that the compound L profiles have the optimal moment of inertia-material consumption (effective area) ratio.
For the stretching effort to be optimal, Template:Mvar or Template:Mvar (the section modulus of the composite structure) must be chosen so that Template:Mvar is smaller than the tension allowable Template:Mvar. The solidarity plates are arranged at 40*i, where i is the radius of gyration (radius of inertia), with the formula (cm).
After fixing the foundation plates and curing the concrete in the foundation, it was time to install the sectioned metal beams, lifted by an 8 m high crane, each section was installed and fixed by high strength bolts (SIR). The top cross beams weigh over a ton and were difficult to fit but eventually the first post was finished and the other posts were moved on.
The working conditions were not easy at all, as the work was also done at a height of more than 10 m above ground level, and the weather conditions specific to the Bușteni area often made these works more difficult. The infrastructure works were carried out between June and October and the beam installation works in the cold period.
If the first pillar was easier to execute, things were not like that with the following pillars, the causes being the very rugged terrain and the weight of the location of the construction site in that area.
Tower 2
Since the terrain is very rough in the area of pillar 2 (as can be seen from the picture) access to that place was difficult for direct access with the necessary materials. The forest road that goes to the Salvamont Bușteni Refuge is accessible up to an area with a clearing where you can see the cable car in proportion to 80% and was used for the dump trucks and other machines that brought the necessary materials (concrete, beams, related materials ) for placing and fixing posts 2 and 3.
2 intermediate routes were established for the funicular that carried the vat into which the concrete brought by the trucks was poured, namely the first route that left that area (light) from the Jepii Mici route to a place located higher up and the second section , from that place to the area of the second pillar. Two electric winches actuated those mining vats in which the fresh concrete brought by the dumpers, which would be poured into the foundations of the second pillar, was non-stop placed. As the technical conditions required that the pouring of concrete in the foundations be continuous (ie without interruptions), 3 shifts were used that worked 8 hours each day and night. The establishment of these two intermediate sections was done with the help of the mountain rescuers from Bușteni who first established the 2 temporary points of the construction site and who then helped to install the winch cables on these 2 segments. In parallel, pillar 3 was being built, which was the most difficult to erect.
Tower three
Being a narrow area for the cable car route, the help of mountain rescuers and special mountain pyrotechnic teams was needed to dislodge some of the mountainside rock. However, during the geotechnical study, it was found that that small valley between the 2nd and 3rd pillars is full of unsuitable sediments to execute a metal foundation.
Those sediments brought over time by rains and bio-natural remains were deposited in a layer that belongs to the categories of "loose soils", in the specialized term, that is, a land unsuitable for foundations. The most suitable place was chosen right at the edge of the rock wall (as seen in the picture) but related soil strengthening works were required, namely: 10-meter long holes were drilled in the anchorage in which mounted cylindrical beams to strengthen that part of the ground and over them the foundation was dug and the necessary reinforcements were installed. The work was extremely difficult, the very act of drilling the rock required several weeks, along with weather conditions that were not always favorable.However, it was found that the distance between the cable car and the rock wall was insufficient in case of the cable car swaying slightly and the solution for the moment was to "cut" a part of the rock more to allow the cable car to be able to sway (at 12 degrees from the vertical axis ).
Towers 4, 5 and 6
The other towers on the plateau were executed much easier compared to the previous ones mainly because there was direct access to the site area. for example tower 4 which is located near the road leading to the Caraiman cabin. The foundation of this tower is at the edge of the Jepilor precipice side, towards Bușteni, in the sense that it includes 2 support beams of the tower.The foundation of tower 5 on the side facing Caraiman is also continuous, both legs of the metal tower, being embedded in the foundation concrete, continuously on that side. To protect the anchor bolts of the pillar foundation and to prevent possible corrosion or damage caused by extreme temperatures on the plateau, around the anchor bolts the level of the foundation concrete is raised by approx. 25-30 cm.Its height is approx. 11 m, being the shortest tower among the 6. The bolts in the foundation are protected with special metal caps that come over the bolts around the foundation plate. Tower 5 is the longest support tower that has horizontal support uprights (those thick beams, crossbeams that are transverse to the face along the length of the axis of the column), no less than 7 transverse beams. Also, on each lateral side, tower 5 has 10 wheels (ie 20 in total) that support the haul cable, being the pillar with the most wheels. The cable car line on the plateau goes from almost straight (angle of 1-2 degrees) to tower 5 where it changes to 35-40 degrees.
From this pillar you can admire the Cross of Heroes of the Nation, Brâna Caraimanului, Valea Jepilor and in the distance the Baiului Mountains with their snowy plains even until May. The climate at this altitude (over 2000 m) is cold, with prevailing mountain winds that can sometimes take on the appearance of a temporary gale.
The flora in this area is predominantly alpine, with junipers frequently found. Because the winds are frequent and can reach speeds of over 100 km/h at the edge of the abyss, the Bușteni-Babele cable car is often closed even if the weather is nice in the Bușteni resort and people are relaxing on the green grass.
However, compared to tower 4, tower 5, which is also located at the edge of the plateau, is directly subjected to the unleashed force of nature (rain, wind, snow, hail), thus making it impossible for the cable car to operate in dangerous weather conditions. The foundation of pillar 5 is also continuous on the side towards the edge of the plateau and in the years after the works were finished, the foundations were over-concreted for more secure rigidity and stability.
Pillar 6 of the Busteni Babele cable car did not present any difficulty in construction, being close to the Babele cabin and the cable car's arrival station, access being facilitated by the road that connects the Babele cabin to the Piatra Arsă cabin and the Peștera hotel.
Completion of site works
The works on the construction of the Bușteni-Babele cable car were carried out in stages, in several execution centers, on the one hand at pillars 1, 2 and 3; at the pillars on the plateau (4,5 and 6), and on the other hand at the stations in Bușteni and on the plateau, so that the works went in tandem, simultaneously, through many teams of workers and 4 points with the organization of the site. Work was done especially in the warm season (June-October) and on the metal structure of the pillars in the cold season. Because of this, the works lasted 3 years (on average, 4 months were worked on the set) - in the period 1974-1977.
The track cable was hauled in stages by 3 winches, taking 2 weeks until the winches pulled all the cable to the Babele station. Placing the cable on the towers required a final effort by the cable car's technical and construction teams, which finally, after being placed on the special track, was anchored to the ends of massive reinforced concrete weights (which are inside the stations) using the technique cuffing and matting.
So in the summer of 1978, in August, together with the personalities of the city of Bușteni and the then envoy of the Ministry of Tourism, the Bușteni-Babele cable car was inaugurated, which for the first time climbed from the altitude of 850 m (the town of Bușteni) to the altitude of almost 2300 m (close to Babele Hut). In the summer season, the cable car can transport even more than 1900 people per day (the average operating time in the summer season on weekends is even 14 hours/day). The cable car runs if the wind does not blow stronger than 15 m/s (52 km/h), and if the wind still blows at the limit, then the installation operates in wind alert, with the cable car slowing down at the towers on the plateau (tower 4, 5 and 6).
Economical effects
By facilitating the construction of the cable car, the access to Babele, the Babele cabin, as well as to the tourist interests in this area (Crucea Eroilor Neamului, Mănăstirea Peștera, Vf. Omu) has been simplified, and it contributes to the development of regional tourism both in Bușteni and in the Valea Prahova.Along with the Bușteni-Babele cable car, access has also been facilitated to the other side of the Bucegi massif, towards Peștera via the Babele-Peștera cable car, put into use in 1982 which also connects Valea Parhovei with other important tourist attractions (Ialomiței Gorge, Peștera Monastery Ialomiței, Lake Scropoasa and Lake Bolboci, etc.) Through this special construction, the Bușteni-Babele cable car remains an important engineering achievement of the country alongside other important cable constructions in the country: the Sinaia-Cota 1400, Cota 1400-Cota 2000 cable cars, the Bâlea Cascada-Bâlea Lac cable car and those in Poiana Brașov. It should be mentioned that these engineering constructions were possible because "the Ministry of Tourism at that time had received important investment funds, I.T.O., then O.J.T. builds in Sinaia in the mountain area - next to the new modernized road to the Alpin Hotel (put into use in 1970)-a cable car Sinaia-Vf. Furnica, with an intermediate station at Cota 1400, with a total length of 1200 m. Then the cabins Brădet from cota 1300 and from elevation 2000 (year 1971) with all the cable car and ski lift facilities in the area. In the Sinaia resort, he builds the Montana hotels (1976) and the International hotel (1982); he restores the Caraiman and Paltiniș hotels (1982 ), Palace and Alpin (1983), the Select restaurant, and rebuilds the Splendid restaurant, with accommodations, as a kind of motel located on the road, towards Bușteni (1985).At Bușteni, the 4350 m long cable car to Babele (put into use in 1978) and the 2600 m long Babele-Peștera section are being built. (put into use in 1982). In the Bușteni resort, the Ministry of Tourism builds the Zamora Complex, a rest house with restaurant and camping (1979), arranges and opens the Vadul Cerbului Inn, building the two accommodation units in two stages (1976) and the grand Silva Hotel set in a picturesque setting under the Jepi and Caraiman mountains (opened in 1982)."
Notes
[1] [2] [3] [4] [5] [6] [7] [8]
Bibliografy
- Gh. Ionașcu, N. Antonoaie, Gh. Ignea, Instalații cu cablu, Editura Ceres, 1982
- STAS 10108/0-78 - CALCULUL ELEMENTELOR DIN OTEL-STANDARD DE STAT 1978
- Gheorghe Nistorescu - Din Plaiul Prahovei la Sinaia (Istorie și Contemporaneitate) - Ed. Arhimede 1995
- Eneș Onea Florin - STATICA CONSTRUCȚIILOR Partea II-a, Editura Ovidius University Press Constanța 2004
- NP 112-07 - Normativ pentru proiectarea structurilor de fundare directă
- Ioan Cadar, Tudor Clipii, Agneta Tudor, Beton Armat Ediția II-a, Ed. Orizonturi Universitare Timisoara 2005
Also see
External links
- ↑ Nistorescu, 1995, pag. 114–115
- ↑ STAS 10108/0-78, pag. 26-27, cap. 8 Elemente supuse la forța axială și încovoiere
- ↑ STAS 10108/0-78, pag. 12-13, subcap. 6.2.1.1 Compresiune axială, cu flambaj prin încovoiere
- ↑ NP 112-07, 2005, cap. 1.2 Prevederi Generale
- ↑ Eneș, 2004, pag 40, cap. Grinzi cu zăbrele static nedeterminate
- ↑ NP 112-07, 2005, pag. 66, subcap 7.33, cap. 7.3 "Fundații pentru stâlpi metalici
- ↑ Cadar ș.a., 2005, tabel clasa de beton
- ↑ Ionașcu ș.a., 1982, pag. 34 cap 1.2 Noțiuni de bază despre funiculare