Landesbetrieb Strassenbau NRW

Gelsenkirchen, Germany

Landesbetrieb Strassenbau NRW

Gelsenkirchen, Germany

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Hagedorn S.,Fa. Schafer Bauten | Neumann W.,Ruhrberg Ingenieurgesellschaft | Schmitz C.,Landesbetrieb Strassenbau NRW | Siebers K.-J.,Landesbetrieb Strassenbau NRW | Weyer U.,Weyer Beratende Ingenieure im Bauwesen
Stahlbau | Year: 2011

From May 2008 to December 2010 a new bridge over the Ruhr River was built in Wetter in Germany. The exposed location of the bridge over the Ruhr valley close to the city of Wetter requires a deliberate designed structure. Within the preliminary plannings, comprehensive studies about reasonable bridge construction systems were carried out, supported by an architecture office. Planned and realised has been a 361 m long bridge with air-proof welded steel box girders and a concrete deck. The maximum span is nearly 84 m and the inclined haunch above the pier is about 9 m high. The inclined haunch has been formed with two diagonal struts to dissolve the construction. In the area of the vertical structured piers outside the Ruhr the bridge superstructure has been constructed with parallel chords. © Ernst & Verlag für Architektur und technische Wissenschaften Gmbh &Co.KG, Berlin.

Current requirements for assessing fatigue behavior in existing prestressed concrete bridges include determining the bridges built-in steel tendons fatigue strength. Standardized S-N curves are normally used for fatigue design in new bridges, which display the tendons' fatigue strength in relation to the number of load cycles under a specific stress range. However, because older design requirements for road bridges did not demand fatigue design, specific curves for older steel types are not available. Yet the structural health of older road bridges must be assessed to determine their safety and viability of further usage. Therefore, the research presented here was undertaken to determine whether standardized S-N curves could be applied to the older prestressing steel found in older road bridges. For this testing, it was determined that some prestressing steel patterns might be reclaimed from an older bridge along the German Autobahn A1 south of the city of Dortmund (Bridge # 67, called Station Westhofen, built in 1957) during the bridge's demolition. Because the steel tendons of this old bridge were not entirely covered by concrete due to bonding failure, some strands were easily obtained. These tendons did not display any signs of damage or indications of pre-damage caused by fatigue. Interestingly, the strands' surfaces showed only traces of rust, which were removed carefully before the tests were begun. Overall, five concrete beams with curved ducts for the steel tendons, which were prestressed with the reclaimed strands, were subjected to fatigue loads. Varied stress ranges were used in order to obtain a full S-N curve for the older steel. The results of these tests were then compared to standardized S-N curves for current prestessing steel. These comparisons indicate that older prestressing steel fulfills the present fatigue requirements so that current standardized S-N curves may also be used to assess the fatigue strength of older steel tendons.

Schafer R.,Dr. Spang GmbH | Spang C.,Dr. Spang GmbH | Timmermann V.,Landesbetrieb Strassenbau NRW
Bautechnik | Year: 2013

For a structural support of a counter bearing of a roadway bridge across the Agger-valley, 14 permanent grouted anchors were installed at the end of the 1970s. In the course of the last bridge inspection it was found, that one of the two installed load cells measuring the anchors forces did not show any data. As a consequence, reloading measurements of the anchors were initialized in order to determine the actual forces of all anchors. The results of the measurement show, that a load transfer from the inner to the outer anchors had taken place leading to lower anchor forces in the inner area and greater anchor forces at the boundary in comparison to the calculated pre-stressing force. Accordingly, the two outer anchors are close to the ultimate limit state. The results of the reloading measurements are evaluated with reference to the global safety concept according to DIN 4125:1990 and the partial safety concept according to EC 7-1. It can be shown, that the distinguished approach of the safety factors for the loadings may be advantageous for the design of the anchors. However, the example shows, that questions remain concerning the inspection of permanent grouted anchors, which © 2013 Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH & Co. KG, Berlin.

Hamme M.,Landesbetrieb Strassenbau NRW | Prenting A.,Landesbetrieb Strassenbau NRW | Neumann W.,Ruhrberg Ingenieure
Stahlbau | Year: 2013

In course of the expansion of the autobahn A 40 the bridge Schnettkerbrücke had to be replaced. Beside of technical difficulties, resulting from the request to build the new bridge while maintaining the traffic, there have been a lot of architectural requirements to the new bridge. The extraordinary solution is a technical and optical ambitious bridge, which combines different types of load carrying actions. The maximal span of the robust composite bridge is 132 m.

Hanswille G.,University of Wuppertal | Heine B.,Landesbetrieb Strassenbau NRW | Porsch M.,HRA Ingenieurgesellschaft MbH | Schmitz C.,Landesbetrieb Strassenbau NRW
Stahlbau | Year: 2015

Bearing replacement at the bowstring bridges over the Dortmund- Ems canal in the lane of the highway A1 near Ladbergen. The bowstring bridges over the Dortmund-Ems canal in the lane of the highway A1 near Ladbergen showed after a short period a frictional wear of the sliding material of the spherical PTFE bearings. In addition at the fi xed bearings creaking noises occurred. In the past the bearings of comparable bridge showed a similar behaviour and comparable damages. Therefore the road administration decided to perform a detailed research program in combination with in situ measurements at the bridge in order clarify the cause of the damage and the short design life of the bearings. The paper gives an overview of the measurements and the research work. Based on the results of special tests, performed at the University of Wuppertal, and the new insides of the measurements a modifi ed fi xed spherical bearing was developed, where the contact area for the horizontal fi xing is made of UHMWPE. © 2015 Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH & Co. KG, Berlin.

Schmidt A.,SCHACHTBAU NORDHAUSEN GmbH | Weissbrich M.,W and S Ingenieure | Hagemann A.,ANKER SCHROEDER.DE ASDO GmbH | Hamme M.,Landesbetrieb Strassenbau NRW
Stahlbau | Year: 2013

The replacement of the Bridge Schnettkerbrücke started with the assignment of the construction company Schachtbau Nordhausen GmbH in September 2005. It was quickly to realize, that the building of this technical and optical ambitious bridge was a great challenge for all participants. The erection had to take place under diffi cult conditions. The disturbance of road and railroad traffi c must be reduced to a minimum. The building of the foundations was very diffi cult. Besides of the building of the new bridge the old bridge must be deconstructed. The interests of the inhabitants of the urban district Schönau had to be respected, because they were disturbed by the site traffi c during the whole construction period. The following paper describes the technical solutions to execute the complex construction process. For a general description of the bridge see [1].

While analysing current traffic volume on German highways, an exceedance of the planned bearing capacity for most of the highway bridges was detected. This exceedance is mainly caused by increasing daily traffic volume, including increasingly heavy trucks with a rising number of axes and load size. In fact, strengthening of most of these bridges becomes necessary to ensure future long-term serviceability of the German Autobahn system. In the meantime, first experiences in terms of structural assessment and strengthening of older highway bridges were collected. Therefore, this report presents gained experiences concerning the refurbishment of more than 250 older highway bridges. Furthermore, recommendations for application, interpretation and evolution of technical regulations are given. For these purposes process steps, methods of choice and technical solutions are described. © Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH & Co. KG.

Gurtmann S.,Landesbetrieb Strassenbau NRW | Hamme M.,Landesbetrieb Strassenbau NRW | Marzahn G.,Landesbetrieb Strassenbau NRW | Sieberth S.,Landesbetrieb Strassenbau NRW
Stahlbau | Year: 2010

The paper reports on the replacement works of nine stay cables of the Rhine River Bridge Flehe, a cable-stayed bridge south of Dusseldorf, Germany. Due to a long service life the stay cables showed some signs of damage and needed to be repaired. Because of foremost damages of nine cables especially open fractures of single wires, they had to be replaced instead. The replacement not only required enormous structural and technical skills, but also engagement of all involved in. This was mainly due to the necessity of keeping the traffic uninterrupted and to prevent any closures of lanes. This administrational demand was successfully mastered. Besides slightly narrowed lanes widths, the bridge's traffic area remained unaffected by this replacement work with traffic able to continue flowing throughout the project. © Ernst & Sohn.

Mauer S.,Ingenieur Buro Grassl GmbH | Rockenfelder R.,Landesbetrieb Strassenbau NRW
Beton- und Stahlbetonbau | Year: 2013

In the course of the six-lane extension of the A1 motorway, the existing viaduct Einsiedelstein had to be partially renovated. It is an vault bridge built in 1938. As a basis for the planning of necessary measures of redevelopments finite element calculations were carried out taking into account the non-linear material behavior of the backfill concrete and masonry vaults for the loads of DIN technical report. The applied calculation methods allow a realistic modeling of the load-bearing behavior of historic masonry structures in the ultimate limit state and serviceability limit state. The calculation results were used for choosing a sustainable measure for the partial replacement of the vault bridge. Copyright © 2013 Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH & Co. KG, Berlin.

While analyzing traffic volume on current German autobahns, it became obvious that the planned capacity of most highway bridges has been almost exceeded by daily traffic volume, including increasingly heavy trucks with rising numbers of axles and load size. At the same time, progressing building standards and enhanced design provisions highlight the inadequacies of such structures. In fact, to ensure future long-term serviceability of the German Autobahn system, there is no way around refurbishing most of these bridges, by combining ordinary maintenance work with strengthening measures, and replacing numerous others as well. A realistic assessment of existing highway bridges that comprises bearing capacity, serviceability, and fatigue resistance in order to evaluate their structural health is a widely accepted prerequisite for a long-lasting refurbishment strategy. Apart from analyzing these bridges in terms of common design rules for new road bridges, such an assessment must consider their overall structural health and increased design requirements for long-term service life, as well as forecasting future traffic conditions for a specific time frame. The provisions reported here for evaluating necessary upgrades of older bridges provide an appropriate tool for setting uniform standards in assessing existing highway bridges to ensure comparability of results and the conclusions drawn from them.

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