Bulletin of the Transilvania University of BraşovCIBv 2015 • Vol. 8 (57) Special Issue No. 1 - 2015

ROMAN BRIDGES ON THE LOWER PARTOF THE DANUBE

A. BARA1 S. KAISER 2

Abstract: The purpose of the paper is to present the Roman bridges builtacross the Romanian natural border, the Danube, during the Roman Empireexpansion. Some of these are less known than the famous Trajan's Bridgein Drobeta-Turnu Severin. The construction of bridges on the lower part ofthe Danube showed the importance of conquering and administrating theancient province of Dacia. The remaining evidences prove the technicalsolutions used by the Roman architects at a time when public works haddeveloped.

Key words: Danube, bridge, pontoon bridge.

1 Faculty of Civil Engineering , Polytechnic University of Timisoara.2 Faculty of Civil Engineering , Polytechnic University of Timisoara.

1. Introduction

The Danube River flows through ourcountry on around 1075 km, of which 225km on Romanian territory exclusively.Among the riparian countries, Romaniahas the longest access to the river,including the Danube Delta. Romania alsoput into operation since 1986 the Danube –Black Sea Channel (Cernavoda –Constanta). The Danube with the Main –Rhine channel forms Europe’s bluediagonal for river transports. Few are thepermanent crossings built on the lowerDanube (Figure 1).

To investigate the origin of the“DANUBE” name we have to go back tothe Celtic tribes who lived in the upperDanube basin. The word “Danu” is of Celticorigins and signifies “swift, rapid, violent,undisciplined”. Emperor Cesar in his work“De Bello Gallico” had named the streamDanubius. Phoenicians and Greeks had

explored the river from the delta upstreambut knew only the lower course, known asIstros or Istria. The name Danubius can befound in the work of Aristotel, Ovid,Strabo, Plinius the Second. “Istros” ismentioned by Herodot and Virgil. Othernations migrating along the stream calledthe river Donau, Dunaj, Duna, Dunav,Dunarea, the name being transformed andmodified according to the language of thecountry.

During the Roman Empire public workshad known a great development. Temples,arches, basilicas, baths, aqueducts are wellknown even in our days. As a first priorityroads were constructed (“via vita”). Anetwork of roads covered the entire surfaceof the Roman Empire. 40000 km ofprincipals roads covered had been built. Theconstruction of roads and bridges reached avery high level during the period of theroman emperor TRAIAN (98 – 117 A.D.)A main road starting from the north of Italy

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During the Traian‘s rule the road reachedthe zone of Turnu – Severin, the border ofthe Roman Empire. On the other side of theDanube was Dacia.

In 101, Emperor Traian started the firstwar for conquering Dacia. The Roman armycrossed the Danube near Drobeta on apontoon bridge. A series of wooden andstone bridges were built to provide access tothe ancient province of Dacia on the otherside of the great river Danube. Some ofthem had a long exploitation, whereas theothers served only temporarily for militarypurposes [3].

The majority of the bridges were built onthe lower part of the Danube from the Iron

Gates to the Black Sea (Figure 1).Themost important of these are the following:- Cornelius Fuscus’ Pontoon Bridge fromVadin (86-87 A.D.);- Traian’s pontoon Bridges in Lederata andDierna (101 A.D.);- Traian’s Bridge in Drobeta-Turnu Severin(103 – 105 A.D.);- Constantine the Great’s bridge from Celei,the ancient Oescus-Sucidava (328 A.D.);- The pontoon Bridges of Emperor Valensin Daphne (367 A.D.) and Noviodunum(365 A.D.).

Among these, there are five bridges thatare related to the need of movement formilitary purposes during the wars betweenthe Romans and the Dacians (theinhabitants of the territory of today’sRomania) at the time of emperorsDominitian and Traian.

The following part describes four of thesebridges whose archeological evidencessurvived until today. Due to their previoussignificance, these have been analyzed inthe last time, in the hope of discovering theenigma of their technical solutions.

2. Cornelius Fuscus’ Pontoon Bridgefrom Vadin-Orlea

The ruins of this bridge were mentionedfor the first time by the Italian-born scholarand eminent natural scientist Luigi F.Marsigli in his paperwork “The Descriptionof the Danube”. He visited during hisresearch on the Danube river banks theRoman fortress from Vadin (todayBulgarian location).He made a detaileddescription of the bridge built by theDacians (and Thracians), providing asketching of the position of the stone pillarsand wooden piers (Figure 2).

Fig. 1. Roman Bridges on the lower Danube

A. BARA, S. KAISER.: Roman bridges on the lower part of the Danube 195

Fig. 2. The ruins of the roman bridge in Vidin-Orlea (after Marsigli 1691)

The ruins of the bridge can be seen even inthe present. Strong pillars were battered downvertically in two rows across the river.Perhaps it was used the same practicaltechnique as the one that helped Cesar’slegions to cross the Rhine. At Vidin-Orlea thebridge stretches over a length of 1000-1100 msomeplace where the water reaches 6-7meters depth. The pillars were probablyintroduced into the riverbed during summerwith the help of a battering ram fixed on theships [3].

The crossing was made then on the shipsthus linked together. It is more than certainthat it did not possessed vaults of wood or anykind of deck. At the same time the navigationwas obstructed. Compared to the bridgeacross the Rhine, the pillars stood verticallyand were not inclined as in the solution ofpermanent wooden bridges.The pillars served for anchoring the shipsonly. As it was only a short-term exploitedmilitary construction the bridge was, ofcourse, immediately dismantled, as to avoid apossible invasion.

Historical sources tell that, the year of theconstruction is the same with CorneliusFuscus’ failed expedition in Dacia in 87 A.D.

Further research of the underwater ruins

would be necessary for finding moreanswers concerning the historical andtechnical nature of the pontoon bridge [1].

3. Traian’s Pontoon Bridges from theYear 101 A.D.

In the field of bridge constructions acrossthe Danube, the conqueror of Dacia theRoman emperor Traian (98-117 A.D.) iswell-known for the bridge of Apollodor ofDamascus, one of the most importantconstruction work achieved by Romans.The interpretation of Traian’s Column inRome gave many answers to differentquestions.

In the spring of the year 101 A.D.emperor Traian started the first war forconquering Dacia and the Roman armycrossed the Danube near Drobeta TurnuSeverin town on two pontoon bridges. Thisis an archeological and logical factconfirmed by the scenes IV-V representedon the memorial Column (Figure 3).

The fourth scene from the Column,shows a military procession passing on thebridge made of the six ships of the same

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Fig. 3. Scenes from Traian Column,showing legionaries crossing the Danube

river on a pontoon bridge with timberwalkways

size and length bound together by woodenbeams. An interesting outstandingconstructive element, is the arch ofmasonry on the left of the scene,whichcould only be the portal of the bridgesituated on the right bank of the Danube.The stone blocks are sustained by twopillars with capitals.

While the location of the first bridge isknown to be the ancient Lederata (inpresent Ram) on the Serbian river side, thesecond one is thought to be difficult toappreciate. However these two locationswere definitely chosen far one from theother, to avoid the unfavorable conditionsencountered at the narrow passage of theDanube at “Cazane” near the Iron Gates.

4. Traian’s Bridge Over the Danube atDrobeta-Turnu Severin

After defeating Decebal’s army andpeace conclusion, Traian realized thatdomination over Dacia province could notbe achieved without building a fixedbridge across the Danube. Consequentlythe need of movement for militarypurposes and the need to administrate thenewly conquered province, located on theDanube left side, imposed the construction

of this bridge, between 103-105 A.D.

Fig. 4. Traian’s bridge over the Danube inDrobeta-Turnu Severin

Having a lengths of over 1200 m,Traian’s bridge, astonished modernresearchers for the enigma of technicalbuilding solution. The bridge wasconsidered superior to all other bridgesbuilt by the Romans. Some hypothesisabout the bridge construction and itsservice life can be presented.Unfortunately, the monograph of thebridge, written by Apollodor fromDamascus who was the architect andbuilder of the bridge, had been lost. Thedocuments elaborated by the researchers ofthe bridge indicate that the more plausibleassumption regarding the bridge siteselection is the possibility of temporarydeviation of a part of the Danube; thereforesome of the piers could be built on land. In1853, a great lowering of the Danubeoffered to a team of Austrian specialistsand to a Romanian engineer, the possibilityto make an inspection on site.

The investigations performed in 1858showed that the lower part of the bridgepiers, differently damaged in time, weremade of broken stone masonry with mortarbinder. The whole structure beingsurrounded by a strong walls made byblocks of crushed stone. The ruined pierslength varied from 21.50m to 22.75m andtheir width from 14.22m to 14.85m [2].

Further information concerning thesubstructure of the bridge, was obtained in1909 when the Romanian HydraulicService ordered the demolition of two

A. BARA, S. KAISER.: Roman bridges on the lower part of the Danube 197

ruined piers located close to the Romanianshore, because they obstructed thenavigation along the river. On thisoccasion when divers worked in theDanube area, they discovered traces ofwooden caissons used for the constructionof the piers. The piers were erected by twomethods:1. A part of the piers were constructed onthe land subsequent to the Danubedeviation along the southern channel;2. The other piers located in the Danubewere constructed with open woodencaissons provided with two walls sustainedby wooden piles, between which hydraulicconcrete (mortar) was cast. The sedimentinside of the caissons was removed out, theground consolidated by broken stones(Figure 5).

Fig. 5. Bridge end with portal andfoundation (reconstruction)

The most difficult aspect of theconstruction seems to have been thefoundation of the piers on the riverbed.These 20 piers were provided with front-breakwaters and downstream-breakwatersof the same shape. On the outside of thepier two rows of wooden piles wereidentified having a square cross section

and with wooden planks inside, whichwould lead to the idea of a cofferdam. Onthe outline of this enclosure regularlywrought stone blocks were identified, inthe form of a dry masonry. Inside of thismasonry blocks of Roman cement concretewere found. Some of these blocks wouldhave pieces of broken bricks inside asaggregates. The concrete and stone blocksof the foundation were tied together bymeans of lattices made from oak treetrunks. The foundation was laid directly onthe bottom of the Danube River (Figure5).

They would support the superstructure,that was conceived by wooden arches(with a remarkable span of 51 m). Theabutments are today the best preservedelements among the ruins of the bridgethanks to their special masonry.

The images shown on Traian's Columnin Rome, as well as ancient coins clearlyindicate a wooden structure combined witharch structural elements (Figure 6).

Fig. 6. Scene from Traian's Column inRome

After the demolition of the piers, the oakbeams were preserved at the museum fromDrobeta - Turnu Severin. In 1906 at theNational Romanian Exhibition, the Frenchengineer Edgar Duperex, tried to restorethe bridge; he achieved a model scale1:100, completed with the portals of thebridge (Figure4). This model is nowadaysin the museum from Drobeta-TurnuSeverin) [2].At the end of these considerations, somehypothesis about the destruction of the

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bridge is presented; there are two theories:subsequent to Traian's death in the year118 the destruction of the superstructurewas ordered by the emperor Hadrianus hissuccessor. Probably this decision wastaken when the barbarians got into Dacia;the second view indicates that the bridgedestruction was caused by the floods. Wedo not know the exact details.

As a conclusion, the bridge over theDanube in Drobeta - Turnu Severin wasone of the most important constructions ofthe Roman empire. It is sure that the bridgewas not built only for a single militarycompany; it was constructed for years onthe purpose of strong connection with theterritories over the Danube.

Even nowadays the ruins of one pier canbe admired on the Romanian river side.

5. Constantine the Great’s Bridge fromCelei

Information about this bridge is found inthe late Roman literature. The ruins of thisbridge can be observed until today but in avery modest condition. The bridge can bealso easily located between the Bulgarianvillage Ghigi and Celei (near Corabia) inRomania (Figure 7 a).At that time twoprosperous cities existed here: Oescus onthe right, respectively, Sucidava on the leftbank of the Danube [1].

The bridge was inaugurated byConstantine the Great in 328 A.D. and itrealized a permanent contact with thenorthern Danubian territories.Archeological discoveries and historicalresearch conducted to the same technicalsolution adopted for Traian’s bridge(Figure 7 b).

(b)

Fig. 7. Final span of the bridge(reconstruction)

6. Conclusions

Historical data and archeologicalevidences prove that a significant numberof bridges were built on the lower part ofthe Danube, in comparison with otherregions situated at the border of the ancientRoman Empire. These bridges wereconstructed in this area on the purpose ofachieving a strong connection betweenDacia province and the Roman Empire.

References

1. Tudor D.:Podurile romane de laDunarea de jos(”Roman Bridges overthe lower Danube”Romanian AcademyPublishing House,1971,Bucharest).

2. Popa N., Bancila R., FloreaS.:”Traian’s Bridge over the Danubeat Drobeta Turnu Severin”FirstInternational Conference Bridges onthe Danube, Vienna- Bratislava-Budapest, September 1992.

3. Florea S., Ionescu C.: Podul creaţie,trăire şi cunoaştere (“The bridge:creation, passion and knowledge”[Vol. 1])