Innovative experience of Institute Stroyproekt and use of composite decks for short span bridges

The words “Aesthetics of Reliability” as our official slogan fr om long ago reflect not only a general professional philosophy but also a particular professional approach. This approach has been embodied into the projects implemented by the company since our very first independent steps.

A miser pays twice

In a certain sense, we were lucky to have St. Petersburg Mostotrest among the first clients as they deal with a day-by-day operation of bridges. Moreover, Mr. Y. Petrov, who used to be the director of Mostotrest at that time and a great expert and “patriot” of the Northern Capital bridges, demanded fr om us to ensure first of all a long-term service reliability of the bridges. Besides, he always emphasised that we live and work in St. Petersburg, and therefore we have no right to build unsightly bridges or to design just a common structure. The vector of development that he has designated for Stroyproekt almost fully complied with our own perceptions and preferences. However, the real situation with Russian road industry in the 90-es could hardly expedite the task! Russian construction regulations and SNIP norms (which are being currently upd ated) are dated back to 60-es and 70-es when the engineering ideology was mainly focused on materials saving. The economic efficiency was the basic criteria for design evaluation and some Russian designers still follow up this approach. In contrast to this, we always strived to achieve a reliable structure while providing for rational consumption of steel and concrete. 

St. Petersburg bridges clearly illustrate the difference of these two design approaches. Among the Neva River bridges for which we have produced a reconstruction design, Troitsky and Dvortsovy Bridges withstood about 100 years without major repairs. Besides, their structural elements mostly remained in fair condition and required only some repair but not replacement. On the contrary, the Lieutenant Schmidt Bridge (or Blagoveshchensky Bridge), which has been recently reconstructed according to our design, has quite a different fate. After it was reconstructed in 1936 – 1939 according to the design by Academician G. Peredery the bridge could stay about sixty years only. The Volodarsky Bridge built in 1936 according to G. Peredery design could survive even less without any repairs: it was reconstructed in 1986 – 1993.

In our time, we were taught to follow up the example of G. Peredery, who being an apologist of constructivism believed the more rational was the more beautiful. Besides, this principle was so jealously used in the late Soviet period that presently the Peredery’s arches in Volodarsky Bridge of 1936 look much more attractive than the present facade of the same bridge. However, the practice proves that principles of the bridge reliability and durability do not contradict the beauty concept. In the 60-es – 70-es they relegated the aesthetic component to the background while pursuing the efficiency and almost neglected bridge architectural aspects. During celebration of the company’s 20th anniversary in 2010 we were very pleased to learn fr om one of our guests that we had discovered a new bridge design approach since any bridge designed by our company had its individual “face”.   In fact, this is not a new but once generally accepted and later forgotten approach. When designing we should always keep in mind that the public do care about a visual appearance of bridges and other road works. If not a specialist, you would never be able to assess the structural design efficiency but you can always notice whether the structure is beautiful or not. Therefore, we se t up an architectural group within the company at the very beginning of our professional activities.

Dispute about composite reinforced concrete

So during our first independent projects, partially in line with Mostotrest requests and to some extent in line with our personal beliefs we already intended to change the prevailing approaches. The first project where we were assigned to be the General Designer was a small bridge over the Slavyanka River at 676 km of Moscow – St. Petersburg motor road (1995–1996). We have proposed a new design concept of composite decks for small bridges that included a cast-in-situ slab and flexible studs made of rebar steel. Unfortunately, not all the solutions for this bridge were realized, nevertheless later on in 1997–1998 our concept was implemented for rehabilitation of the bridge over the Saimaa Canal in the city of Vyborg.

Bridge building in Soviet Russia was commonly based on general use of precast beams for small spans. Carriage way slab joints used to be a week point of this type of structure. When in the second half of the 90-es Stroyproekt was involved into bridge inspection, design and supervision for the Russian Bridges Rehabilitation Program of International Bank for Reconstruction and Development, we had a chance to see with our own eyes the terrible condition the bridges were. Just for some thirty years of operation the bridges made of precast beams got completely out of order! And these were the most common bridge structures. Therefore, we started to search for an alternative to precast beams that would ensure structural durability. 
At that time in Russia cast-in-situ concrete started to gain some popularity which it already had abroad. In particular, this technology was used for Moscow Ring Road construction. However, Moscow Government with its financial capabilities was one thing, and the rest of Russia was something different. For Russian contractors cast-in-situ reinforced concrete structures were unusual and inconvenient, they required new equipment and labor training and therefore their construction was more expensive in general. For years our bridge builders had accustomed to precast structures that were prefabricated at plant and erected at place. We realized that cast-in-situ reinforced concrete would hardly ever become widespread in Russia and we found an alternative that was actually evident since it had already been mentioned in publications of N. Streletsky, V. Bystrov, etc.

We started using composite reinforced concrete for small spans. One could not even dream of it during the Soviet times: steel was a critical material required for defense industry and its use was strictly limited. In bridge building, steel was used only for over 60m long spans. This restriction ceased to exist only in 90-es so we started trying: first at the Slavyanka River Project and later on at Saimaa Canal.

Wishing to abandon precast slabs and to start using cast-in-situ slabs, we have considered Finish projects as an example. A problem with studs had to be solved. Soviet rigid studs often broke slabs (and beams as well) and made them non-durable. Today flexible Nelson studs are widely used. And for the bridge over Saimaa Canal we managed to implement an interesting invention of O. Bakhurin, a specialist of Scientific Research Institute of Concrete and Reinforced Concrete. He proposed a special welding machine for ribbed bar welding. Rebars could be welded with this machine at place, which was much cheaper. Unfortunately, Bakhurin welding machine (Gefest) was not accepted for mass-production and today contractors have to buy foreign-made Nelson studs and foreign welding machines for them.  A high strength concrete was used for the Saimaa Canal Bridge in addition to flexible studs made of reinforcement steel in leave-in-place formwork. This relatively small project became a starting point for further professional development of the company including elaboration of our own design methods.
Although we had made our choice, ideological disputes whether composite reinforced concrete was appropriate for short spans continued for a long time.

When back in 1999 Stroyproekt was developing the design for St. Petersburg Ring Road interchange with Primorsky roadway near Gorskaya railway station, we used composite structures not only for the main overpass but also for curved ramps of 60 m radius. It was an innovation as well since curved beams were considered to be difficult to manufacture. However, our solution was successfully realised and later on we have often used it when designing the Ring Road facilities.  At that time construction of the Ring Road that had been awaited by the city for such a long time had just started, and we tried to make the Gorskaya interchange architecturally  easy recognisable. We were not required to do so; it was our own initiative. White А-shaped (or trapezoid) pylons imitating entrance gates made this large structure look light and stylistically complete. This interchange opened in 2001 became a symbol of a new stage of the Northern Capital transport development that had begun with the Ring Road construction.

Neither were we required to restore a historical look of the Lieutenant Schmidt Bridge. Committee on State Control, Use and Protection of Historical and Cultural Heritage requested only to preserve pavilions and memorial plates on the draw span. But we considered restoration of the bridge appearance as designed by S. Kerbedza to be our professional duty and our duty as Petersburgers as well. And we did so, and when rehabilitation was completed it became clear for the city administration that it was not Lieutenant Schmidt Bridge any more, it was Blagoveschensky Bridge. This is how the bridge received back its original name.

The St. Petersburg World Club awarded Institute Stroyproekt a Sign of Conformance for Blagoveschensky Bridge rehabilitation. The same reward was given to Mostootryad 19 and Committee on State Control, Use and Protection of Historical and Cultural Heritage. However, in this particular case the Committee merits are not so evident. Based on the Committee’s requirement the memorial plates reading that the bridge was named after Lieutenant Schmidt, a hero of the revolution of 1905, and rebuilt in 1930s based on the design by Peredery have been preserved. We addressed to the Committee indicating that these plates misinform citizens and guests of the city and asked for additional plates to be installed to mention rehabilitation of 2006 – 2007. However, we received a refusal to our request. But we do hope that justice might be finally served.
Though Blagoveschensky Bridge returns us to the middle of XIX century it is a modern structure wh ere the most interesting technical solutions have been realised. The bridge became one and a half times wider (from 24 to 36 m wide) and was redesigned for nowadays loads, but at the same time we managed to preserve historical foundation of wooden piles. It became possible due to the deck self-weight decrease and a new design solution wh ere the draw span deck is supported not by piers but by fixed decks. Such structure allowed achieving central bearing on the draw piers and excluding eccentricity.

Guss asphalt was used at Blagoveschensky Bridge; by that time it already gained good reputation at the draw span of Alexander Nevsky Bridge, at Troitsky Bridge and at the Ring Road. We brought guss asphalt technology to Russian bridge building practice after it had been introduced by ABZ-1 Asphalt concrete plant that was the first plant in our country to master this German technology. Guss asphalt technology for bridge building has solved a lasting problem with the bridge floor at draw spans and orthotropic plate.

Europe is left behind
 
In the meantime, let us go back to our favorite topic of composite reinforced concrete for intensive use of which we were bitterly criticized on numerous occasions. Normally, Russian bridge industry (and indeed other spheres) lags far behind the worldwide tendencies. State-of-the-art achievements are usually introduced in our country with some 10 – 15-year delay. However, the situation with composite reinforced concrete has progressed in another way. When we first applied composite concrete, cast-in-situ concrete was still very popular in the West and only at the turn of the century they started changing to composite concrete. Moreover, the design experience of the Western High Speed Diameter in St. Petersburg has proved soundness of our position.

The Turkish and Italian Consortium IC Içtaş– Astaldi have been engaged to construct the most complicated Central Section of the Western High Speed Diameter (WHSD). One of their first requests was to exclude cast-in-situ concrete structures in favor of composite ones. As stated by well-known French company Setec tpi, which is a consultant of our colleges from Turkey and Italy, cast-in-situ concrete is considered old-fashioned in the present-day Europe and is mostly used by European companies in the Third World countries wh ere there are no qualified steelwork manufacturers. 

So, we got convinced of who was actually right in that long-standing ideological dispute. The material that we first introduced about 20 years ago at our own risk is now widely used in Europe: composite reinforced concrete proved to be less expensive, more suitable and durable.

As for reinforced concrete beams, unfortunately many Russian regions still use them in bridge construction. From our side we have suggested GK Rosavtodor to modify the design of standard reinforced concrete beams. Stroyproekt has found a common and workable solution that allows managing disadvantages of the present beam designs without re-equipment of manufacturing plants. Our idea has been accepted positively and we hope that a new standard beam design will be developed and approved.

The project of Western High Speed Diameter has become a quintessence of our professional experience. In general, the WHSD is an innovative project from various standpoints. It is the first expressway, which will connect the southern and northern outskirts of St. Petersburg to the city centre. Besides, it is also the first toll motorway of the Northern Capital of Russia. Finally, the WHSD project includes several design solutions that deserve a more detail consideration. Among them, the unique bridge structures of the WHSD Central Section that will form up St. Petersburg Sea Façade, in particular:
-        A double deck bridge across the city main navigation channel, named as Sea Channel (the bridge is 734 m long; its central span is 168 m long; the underclearance is 52 m);
-        A cable-stayed bridge across Korabelny Fairway (the bridge is 620 m long; its central span is 320 m long; the underclearance is 35 m);
-         The extrados bridge across Petrovsky Channel (the bridge is 580 m long; its central span is 220 m long; the underclearance is 25 m).

The major part of the WHSD route runs through a narrow corridor across compact industrial areas. Lack of free space was the most pronounced at the section from Stacheck Prospect to the Ekaterinhofka River (Construction Stage II). To cope with these constraints our designers have proposed double-deck trusses for this section and also for some Stage IV sections. Double deck trusses allow separating opposite traffic flows to the lower and upper deck correspondingly (providing 4 lanes in either traffic direction). Horizontally, the trusses are located on a variable radius curve with superelevations and transition zones, which is very unusual for double deck structures. The longest span is 144 m.

The WHSD design includes some other solutions which are not so large-scale but still quite interesting. As an example the toll plaza at the exit ramp to Automobilnaya Street (Stage I) can be taken which has been constructed on two levels due to the extremely space-limited area.
Aesthetically the WHSD route has been designed in a uniform, recognisable and dynamic mode: the arc-shaped lighting poles are integrated with the curved noise screens. For this reason the WHSD is perceived not just as a long-distance motorway but as a continuous engineering and architectural complex. 

“Philosophy” in action
 
Of course, it is impossible to give a full overview of all innovations introduced by Stroyproekt or just interesting projects within the single article. Nevertheless, I wish to highlight several projects that reflect our professional philosophy in the brightest way.
In 2003 we developed the design and working drawings for reconstruction of the bridge across the Volga River in Kimry town of Tver Region. For the first time in Russia, strengthening of the existing prestressed reinforced concrete box deck was implemented by means of the cable-stayed system. To level the carriageway we have utilised light and nanomodified concrete with bulk weight of 1.6 t/m2 and plastomagnetic balls instead of crushed stone. This has allowed increasing the bridge capacity up to standard values and straightening the carriageway profile. 

The Lazarevsky Bridge across the Small Nevka River stands out for its distinctive and expressive design developed in 2000 – 2009 (with some breaks) for the bridge reconstruction. In fact, the old multiple span beam bridge has been reconstructed into a modern cable-stayed bridge with dynamic and at the same time very exquisite outlines. Due to that the renovated Lazarevsky Bridge has been repeatedly used as a model when shooting films.

Construction of a new bridge across the Ob River in Novosibirsk (located at the alignment of Olovozavodskaya Street) is the most remarkable current project of the company. The bridge comprises an arch river span (a tied arch with inclined suspenders, so called “network arch”) 380 m long, which is a record value both for Russia and for Europe. Visually, the 70-m high arch resembles a gigantic red bow that is one of the Siberian symbols represented in the coat of arms of Novosibirsk.

Participation in the project for reconstruction of the M-4 Don Federal Road is an important milestone in the company’s life. Comparison analysis of Russian and German road design codes was carried out in 2010-2011 when designing the road toll section from KM933 to KM1024. The work has been implemented in cooperation with a German company BEB at the initiative and support of the Client, Russian Ministry of Transport and State Company AVTODOR. The design has been developed simultaneously according to the Russian and German standards. This also allowed choosing the most optimal design solutions for the project. The results of such design experience became of high demand as they provided a good basis for elaboration of amendments and revisions to the Russian road design standards by way of their harmonisation with European codes.

Interesting solutions for toll-operation management and access roads to settlements have been implemented at the M-1 Belarus Road section from 33 to 84 km (that is also planned to be a paid road). Besides, decks made of polymer materials have been used for foot bridges.

Finally, Sochi transport facilities designed by Stroyproekt for Winter Olympics 2014 are unquestioned innovations. All of them were designed considering high seismic risks, mountain relief, and strict environmental requirements. Sochi Olympics transport facilities are modern world-class structures. Among them is Kurortny Prospect backup road, almost the entire route of which is located on flyovers and in tunnels (the longest tunnel is almost 3 km long), and Sochi bypass motor road (Stroyproekt developed the design for Stage I start up complexes 2 and 3 and Stage III), the bridge over the Sochi River, and a number of big traffic interchanges.

Working in various regions of Russia Institute Stroyproekt has often had to look for and to find new and unusual design solutions together with its partners or on its own. The scope and complexity of these solutions have been different, but any of them has been a result of engineering creativity, ability to cross the limits of standard procedures and to put aside an experience burden (often inherited from the previous generations) for the sake of finding a new way to be more perfect against the traditional one or even the only possible in a particular situation.






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