The Rehabilitation of the Bridges on the Corridor IV

With almost one year ago, Bucharest - Campina railway section, which is part of the northern branch of the Corridor IV Helsinki, there has been started off the most important rehabilitation and modernization program of the Romanian railways. The financing of the project on the entire Bucharest – Brasov railway section (400 million Euro) has been granted, as we have already mentioned in our first articles related to this subject, through a loan in an amount of 200 million Euro granted by European Bank for Investments and other 200 million Euro allocated by the Government of Romania, in local contribution regime.
As it is already known, for a better organization and for the increase of the activity efficiency, the works have been split up in eight lots. If in the previous articles we have mentioned about the rehabilitation of the lines included in the first lots, as it follows we are going to describe the works of the 4^th lot, which includes the building and the repairing of the bridges, culverts and tunnels and the banks protections.
The tender for the rehabilitation of the bridges over Colentina rivers – km 12+903, and Ialomita – km 38 + 070, there has been won by SC Arcada Company SA Galati, as a constructor, and RIMS CO SRL, the main designer.
Arcada Company SA Galati, the constructor for the part of the bridges and culverts included in the lots 4.1 and 4.2, has started the collaboration with the railway sector since year 1990, through works executed for CF Galati, Iasi, Constanta and Bucharest Rail Regions. Mr. Spiru Mantu, the manager of this company, has declared to us that at almost a year since the starting off of the construction and rehabilitation works of the bridges and the culverts, he can appreciate that this debut has been a “successful one, even if during the unfolding of the rehabilitation program there have also occurred small issues – inherent, we can say – as it is the fact that we are forced to request line closures, which are not stipulated in the instructions. But it is also our interest and also CFR’s to respect the deadlines. If there are no line closures or if the traffic is not limited to speed restrictions we can not accomplish the works in due time. The postponing means, in fact, wasting our time. We consider that only with certain efforts we will succeed to finalize until the end of the year all the consolidation works at the bridges and culverts which are part of the forth lot.”
RIMS CO SRL is the designer for the details of the works within the 4.1-4.2 lot, which Arcada Company is in charge with the execution. Being selected from a large list of specialty designers which have available all the quality documents and authorizations related to the railway, RIMS CO company proposes to finalize up to September the last details regarding the designing stage, and if the rhythm is the present one and if there do not occur any graphic changes, the assistance part should be finalized before the beginning of the cold season. “Anyway, until the end of the year our company hopes to establish a competition also for the works that are performed on other railway sections of the Corridor IV”, has declared Mr. Adrian Sandu, engineer, the general manager of RIMS CO company.
The design of the works included in the lot IV has started the last year, on May, but due to the reasons for adaptation to the field, it continues up to the present time. And, as the works evolve, there are noticed numerous disorders, due to the fact that the discovering the various infrastructures there has been found something else instead of what was stipulated in the technical project.
Besides the so-called designing activity, found in full development stage, RIMS CO also provides to the constructor technical assistance during the execution of the works. This is not an obligation imposed by the beneficiary or by the constructor, but only a sign of the interest of the designer to contribute to the well development of the activity, through maximum emergency measures, so that the terms of achievement of the works will not be delayed, and the quality of work on the site has no impediments.

The bridge over Colentina river

Until the end of May, from the lot of 4.1-4.2. there have been finalized works at the km 4, km 11, km 12 (the third line), km 40 (at Crivina) and km 29.
Along the route, up to km 12, there have been stipulated several works at the culverts – classical solution and with under-crossing of embankment.
The bridge over Colentina river from the km 12 + 903 has a clearance of 20 m, the structure being compound of metallic beams, framed, in steel, in completion with an enforced concrete side, the railway being practically place on the ballast.
The rehabilitation works are executed at the old bridge shelter. There are three traffic lines, two of them on the main section, which is in rehabilitation stage, where there are developed the works at the columns and decks, and a connecting line – Buciumeni -, where the circulation is performed presently. The works on the third line have been executed in a quite sustained rhythm. According to the declarations of the manager, Mr. Adrian Sandu, “there have been executed the abutment, which are founded on columns made of enforced concrete, eight on each abutment, and the infrastructures have been ready at the middle of November 2001. In parallel, there have been realized the scaffolding and the platform where there was assembled the deck. We were in a hurry so that according to the first part of the contract to finalize the rehabilitation works on the third line, where the traffic is performed now, so that we still have the possibility to execute besides the traffic, the infrastructures and the superstructures.
On the first and the second lines, the infrastructures have double lines, founded on 24 columns (12 on each bank). The decks, which are independent (compound structure, steel-concrete) will be placed on pillars, so that we can execute superstructure works. In the moment when it is reached the “age” of the concrete indicated in the project, the abutment can receive the respective decks. After that there is going to be spread ballast in the vat. We are hoping to put into operation again in two months the first and the second lines. If there are no other priorities, of course”.
Further on, after the km 12, there are some culverts that have to be rehabilitated through the execution of some inside coating, so practically it is about a repairing process.
Presently, where the works are in execution stage, the traffic is performed on the temporary bridges – as it is the one over Colentina river, from km 12 (third line)-, with a speed restriction to 15 km/h.

 

The bridge over Ialomita

The current bridge on the railway is over Ialomita river – km 38 + 070, which has been built between the two world wars, on the location of an older bridge, on simple track. Built between 1934 – 1935, the new bridge has been achieved for a double track, with bared beams, with decks independent for the two lines.
Being put into operation after almost 70 years there was natural to occur, in time, enough problems. And the need to solve them! Thus, various verifications and technical expertise have revealed the necessity to be performed certain consolidations. There was also reached the conclusion that the decks have to be replaced because their state was a threat for the safety traffic… The opportunity to achieve this imperative has occurred now, once with the starting off of the rehabilitation works on the Corridor IV.
As it was natural, before the passing to he achievement of the rehabilitation program was performed an attentive expertise of each bridge, from Bucharest up to Brasov. In point of the bridge over Ialomita, the results of the new expertise has confirmed the conclusions of the first one, which has been materialized only in a … temporary consolidation performed in year 1985. This time, there was imposed the idea that the optimal solution for the rehabilitation of the bridge is the replacement of the existing decks!
The specialists within ISPCF, who have achieved the technical project have thought that it is better that the respective structures – on three clearances – to be some new compound structures, made of steel and enforced concrete, with the concrete side alike with the one of the bridge over Colentina bridge, from km 12: the support for the broken rock prism and the track in the bridge area.
There has been stipulated the consolidation through coating at the level of the elevation and the reconstruction of the bushes banquets for the infrastructures, so that the height on the supports will reach at 4.50 to 3.70 m. Thus, there is a difference of level between the two structures, the old one and the new one. All these adaptations will be performed under circulation, and the closure of the traffic will be operated, alternatively (first of all on one line, then on the other) in order to replace the old decks.
The manager, Mr. Adrian Sandu has presented to us the most important technical details of the works. Thus we have found out that the “infrastructures will be coated, will have another architecture, and the initial structure will be coated in “clothes” of enforced concrete, which will confer to the structure resistance and stability, meaning a protection against the external agents. In parallel, the specialists from Arcada, the constructing company, will also reconstruct the bushes banquet, namely the supporting part of the decks.”
In parallel with the bridge, there have been mounted pillars (temporary supports), over which will be placed the beams. The mounting of the new decks – this supposing the assembling of the three railway sections of which there is made the metallic structure – there are made with the supporting of the sections on the temporary pillars. The scaffolding for the support of the shuttering at the reinforced concrete slab is similar to the one meant for the bridge over Colentina river.
This time, the situation is more difficult. If for the bridge at the km 12 has been used a structure having the length of 21 m, here it is necessary one of 33 m, which could not be brought in only one piece, its clearance diagram exceeds the possibilities of transport either on the railway, or on the road. Pursuant to a common decision of the beneficiary, the consultant and the executor, have agreed that for the metallic structure to be reused some longer decks taken from the coal line, that are preserved in Tg. Jiu area. Practically, the constructor is going to transform the 18 railway sections decks, in order to adopt the new requirements and the new standards in force. The cleaning operations, the blasting, the manufacturing and the cutting at the new structure dimensions will be executed on the site, with specialized control.
The bridge is spectacular, having a high infrastructure, so that the mounting performed aside, on some scaffoldings (the pipe supporting pillars mentioned above) which allow the swinging of the three railway sections through the respective joints, achieved with high resistance screws, as well as the shifting of the structure on the location.
The respective works last for three month on each line, fact that means that in six months they will be ready, the resistance part and the one of the equipment are going to be completed with electrification pillars and cables.
So, the three elements are mounted on temporary pillars, they are connected when they reach at the precise counter-arrow, the joints of the three sections are connected, then the respective structure (meaning the three railway sections, which become just one) are supported in a very attentively calculated position, the slab is cast, which is manufactured with metallic structure, on the temporary supporting pillars. So there is freed the upper side of the pillars and of the abutments, there are placed prefabricated blocks (the so-called prefabricated bushes), in order to support the decks, which are placed on the piles and abutments. Only in this point there is performed the shifting of the track (the bringing of the respective bridge from the lateral position in the normal position, the definitive one), in the location, namely right beside the traffic line, but a higher quota; after that there is descended with presses on supporting equipment.
When the decks are ready, and the slab is mounted and ready to receive the broken rock, the traffic will be closed on the respective line.
The operations are not finished here. “We have the intention, to the extend of the necessary time, according to the number of days of closure of the line and the general graph of execution approved by the company, to make the corset of the prefabricated bushes on half structure. In the moment in which the respective operation has been executed, with the decks supported on the temporary pillars, on the superior side, there are performed the treatments at the transversal junctions between the decks, there is filled up the vat with broken rock, there is brought up the track, there are performed tamping works, and there are made all the preparing operations for putting again into operation of the track. In the cable boxes which are mounted outside the metallic parapet, there are introduced the afferent cables of the respective traffic line and there are performed all the operations related to the equipment. On the piles there are left some special consoles with fastening plates for the electrification pillars afferent to the respective line. And, of course, maybe not simultaneously, but shortly, there will be performed the closure of the next line (2) in order to execute the same operations.

Many specialists consider that the works at the bridges as being some…accidents in the global action of rehabilitation of the railways, so that “the hot spots” of this process are the embankments, the superstructure, the switches, the stations etc. But the importance in the provision of a well development of the traffic represents a certainty. As for the complexity of this works… there is for sure that, the above - mentioned simple enumeration will have been more than convincing.

Oana Bran