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The construction method is a key technical factor to determine whether a concrete arch bridge design is reasonable and applicable. In most mountain areas of western China, a new construction method...

Two sections of an old decommissioned filler-beam railroad bridge were test loaded in order to determine their structural performance and ultimate load. The loaded bridges were studied with two kinds of finite element (FE) models to observe how well the design theories of composite structures match the observed behaviour of the almost 100 year old bridge decks. The objects of research were the existence and level of composite action between the steel beams and the concrete slab as well as other factors related to the condition of materials or structural details that could have had an effect on the bearing capacity of the bridge. Comparison of the test results and FE models gave information on the structural behaviour of the loaded filler-beam bridge sections. The results can help in the assessment of other similar structures.

The aim of this paper was to research the topic of how to resolve the problems of technology used for erection of bridges, using prefabricated box beams (full-span method), in mountain areas and er...

The Second Dolsan Bridge has a total length of 464 m, consisting of a 230 m main span and two 117 m side spans. This is the first time that a cable-stayed bridge with a concrete edge girder has bee...

Dongping Channel Bridge, a significant project of the new Guangzhou station, is the longest arch bridge on the Wuhan-Guangzhou high-speed railway. A half-through continuous steel-truss arch bridge ...

The Yumekake Bridge is an extradosed prestressed concrete bridge over the Kumano River in a steep ravine located near the UNESCO World Heritage Site of Sacred Sites and Pilgrimage Routes in the Kii...

This paper presents the conceptual design and technical solutions for the bridge over the artificial lake of Ptuj (power plant reservoir on the Drava River) on the new south main road, which connec...

Sanchaji Bridge across the Xiangjiang River is located at the northern section of the Second Ring Road Project in Changsha, Hunan Province, China. Its main span is the longest in the world among all self-anchored suspension bridges constructed using double towers and double cables till now. For a self-anchored bridge, structural behaviour and construction methods are totally different from those of a traditional suspension bridge. A main cable containing 37 prefabricated strands and streamlined steel box cross section was used as stiffened girder with a height of 3,6 m. A fully welded anchoring chamber was adopted to connect the main cable with the stiffened girder for the first time. The main tower is of reinforced concrete with a variable hollow box section. As for the construction method, launching methods were selected for the erection of steel box girder and non-stress method for installation of hangers. The construction of the bridge was started on 10 September 2004 and completed on 1 September 2006. The completion of the bridge effectively relieved the traffic pressure in the northern region of Changsha and played a vital role in improving local economy. This paper introduces several features of the Sanchaji Bridge, including type selection, structural behaviour and construction methods. (A)

Connecting the two islands Jintang and Cezi in the Zhoushan Archipelago in the East China Sea, the Zhoushan Xihoumen Bridge was constructed as a two-span, continuous steel-box girder suspension bridge with a main span of 1650 m because deep-water foundation could be avoided. Since the bridge site is located in a typhoon-prone area with very high wind speed, the stiffening girder of the bridge was designed as a twin-box steel girder, innovatively adapted for the purpose of wind-resistant design. The design criteria, construction conditions and structural design of the bridge are systematically introduced in this paper. (A)

The Nanjing Dashengguan Bridge is a key project on the Beijing-Shanghai high-speed railway; it is designed to handle a speed of 300 km/h. The main bridge has a large-span continuous steel arch truss structure with a total length of 1615 m. The two main spans over the main navigation channels of the Yangtze River are steel arch trusses, each of which is 336 m long. The arches comprise three truss planes above the orthotropic deck. Erection of the steel arch truss adopted the double cantilever method with auxiliary cables supported by towers on piers. (A)

This paper describes a bridge recently constructed in the province of Trento, Italy, which overpasses the Brennero Motorway and the Avisio River with a steel–concrete composite structure that intro...

The new Shibanpo Bridge crosses the Yangtze River in Chongqing, China, connecting the southern district and the Yuezhong District. This box girder bridge’s long span was made economically and techn...

There are a number of bridges which are designed according to codes without seismic provisions being considered. Such bridges are mostly found deficient and may need seismic retrofitting. Bridges that were built before the 1970s, either in the USA or Japan or Europe, were designed with little or no consideration for seismic demands. The majority of these bridges are supported on reinforced concrete bents at the abutments and pier walls that lack the ductility and strength to resist earthquakes. Besides most of these bridges have short spans (6–18 m) to medium spans (18–90 m). A bridge with a short span may be built with timber girders or with a concrete slab superstructure, whereas a bridge with a medium span is often built with steel girders, precast concrete girders, or cast-in-place box girders. Bridges in general consist of two structural components: a superstructure including the elements above the support and a substructure including the elements that sustain the superstructure.In this paper, the re...

The Garden Route, one of the main tourist attractions and also a major national road on the south coast of South Africa, experienced abnormally high rainfall in August 2006. A major slip failure occurred in one of the road cuttings, known as Kaaimans River Pass, which severely damaged the roadway. The owner (South African National Road Agency Ltd.), immediately took measures to restore this vital link in the national road network. Several preliminary concepts were developed by the project team which included bridge and geotechnical specialists from the owner and the project-consulting engineers. These included a tied pile anchor wall, a tied mechanically stabilized embankment and a half-width pre-cast beam bridge structure. The selection of the most suitable option relied heavily on the geotechnical conclusions by specialists from the project-consulting engineers, after an extensive drilling programme was undertaken to investigate the competency of the underlying rock substrata. A modified version of the first concept was finally decided upon, as this was considered to provide the optimum solution, considering interaction with the adjacent road formation as well as the bedrock profile.uThe new viaduct is supported on eight 1200 mm diameter reinforced concrete oscillator bored piles approximately 14 m long, spaced at 8 m centres and socketed 4 m into competent rock. The superstructure comprises a 7 m wide, 60 m long cantilevered deck that is counterbalanced by an integrated buried jockey slab and supported on the piled substructure. This configuration eliminated a problematic longitudinal joint. The structure is anchored with re-stressable rock anchors, ensuring the stability of the structure and rock formation. In order to minimize the movement between the roadway and structure, the jockey slab is also tied down with anchors. (A)

The new bridge construction method described in this paper involves building the bridge girders in a vertical position and rotating the bridge girders into the final horizontal position. The bridge girders can be built in combination with the pier using self-climbing forms, which allows for lower costs and a shorter construction time. The span of the bridge girders is reduced by the compression struts or tension ties, which results in substantial savings in construction materials compared to the balanced cantilever method for bridge construction. The method proposed was successfully applied in two field tests on bridge models with spans of 15 and 17 m. The first test involved the use of compression struts and in the second test the bridge girders were raised using tension ties. Results of the field test on the compression strut bridge are compared with a case study.

In Brazil, composite log-concrete bridges are considered a viable alternative for municipal and rural use, mainly because of their low constructionand maintenance costs and their high strength and stiffness. These bridges consist of a thin concrete slab over round timber beams. Materials are thus used to their best abilities, with timber under tension and concrete under compression. The two components are connected by glued steel bars. This paper presents the field performance of a composite log-concrete bridgeconstructed in December 2004 on the grounds of the University of Sao Paulo. This two-lane bridge is 12 m long, 10 m wide, and has a skew of 15o. The load tests consisted of positioning fully loaded, three-axle trucks on the bridge and measuring the resulting deflections at a series of points along a transverse cross section at mid-span. In addition, an analytical assessment was made, using computer modeling to predict the response of the bridge. The field tests indicated that the composite log-concrete bridge performs adequately without structural deficiencies. (A)

(2007). The Piston-Stayed Bridge: A Novel Typology for a Mobile Bridge at Tervate, Belgium. Structural Engineering International: Vol. 17, No. 4, pp. 302-305.

In this paper it is demonstrated how higher load carrying capacity with respect to combined shear and torsion can be determined by non-linear finite element (FE) analyses of bridges. A prestressed ...

Due to the greater additional stress of prestressing, many serious problems - such as the camber of straight beam being too large, curved beam going crosswise, and columns of rigid beam bridge cracking frequently occurred in the prestress tensioning process of medium or short span prestressed concrete beam bridge. To solve these problems, a new type of twice prestress technology was innovatively proposed in this work. Through theoretical and experimental comparison between this new structure and the traditional prestressed structure, it was found that the application of prestressing twice can significantly improve the mechanical and deformational performance of the low height beam in the construction process and also for long-term use. In addition, a theoretical solution to calculate creep strain and deformation due to twice prestressed with respect to time t were derived in this paper. Finally, the work concluded that this new structure will make it a bright application perspective for the medium and short span prestressed beam bridge to control the deformations. (A)

This paper examines the lock-in phenomenon theoretically and discusses three cases of box girders for which vortex shedding excitation was observed in the prototype bridge, and mitigation was provided by fitting guide vanes to alter the flow in the wake region. A fourth case involves a long span beam bridge for which vortex shedding excitation was mitigated through installation of tuned mass dampers. In addition, the conditions which wind tunnel tests of guide vane designs must fulfil in order to yield results which are applicable to prototype conditions have also been examined. (A)

Using the example of the Ile Falcon Bridge, it is shown that, given proper attention during design and rigorous quality control during construction, incremental launching can be used successfully f...

The Connestogo River bridge, constructed in Ontario, Canada, in 1975, is believed to be the first bridge in the world in which a concrete deck slab on longitudinal girders was designed by taking in...

A steel-wood composite bridge is presented consisting of longitudinal steel girders and a composite decking of wood laminates, which are laid longitudinally and post-tensioned laterally. Details of the first prototype steel-wood composite bridge constructed in Canada are presented along with the results of field testing. Differences between anticipated values and field test results for the global flexural action of the bridge are discussed. Deflections of the wood deck under concentrated loads are also considered. (A)

This article describes a newly developed design of semi-integral bridge abutment which can reduce the soil disturbance behind the abutment caused by thermal changes. The case study described is of the Liguanhe Bridge in China. The bridge has a pile-type embedded abutment. On the abutment cap, a reinforced concrete backwall against the backfill separates the end beam from the backfill. A 25-millimetre gap between the end beam and the backwall keeps them separate even when the bridge expands in summer. The approach slab anchored to the end beam overpasses the backwall and shifts the deck thermal movements to the structure/road interface. Sliding elastomeric bearings rest on the end beam and there are multi-layer plastic films laid beneath the approach slab, and asphalt felts between the approach slab and backwall. The longitudinal restraint of the superstructure is derived from the friction between the approach slab and backwall and between the retaining block and the approach sub-base.

The Second Nanjing cable-stayed bridge over the Yangtze river, China is 11 km downstream from the first Nanjing bridge and passes through Baguazhou, the third largest island in the Yangtze river. The main bridge in the southern section is a cable-stayed bridge with five continuous spans of steel box girder with an orthotropic deck and an epoxy asphalt concrete pavement. The main span is 628 m long. The technical specifications are listed: deck width, design speed, design load, design wind speed, ship collision force, navigational clearance, design flood frequency, deck slope and seismic scale. The design and construction of the deep water foundation of the tower, the reinforced concrete cable tower and main girder are described. The zinc-plated steel cables and their installation are described.

Since the use of steel, reinforced concrete and prestressed concrete as bridge building materials, structural bridge bearings had to be used. On the other hand the gap between bridge and abutment is bridged by means of expansion joints. The target of this paper is to give a very short state-of-the-art-report on bearings and expansion joints for bridges.

The design of the La-Ferte-Steg footbridge at Stuttgart-Zuffenhausen is the result of an interdisciplinary bridge competition. The asymmetric bridge links a slope on one side and a flat meadow on the other. It features a curve in the longitudinal direction with a 6% sloped T-beam superstructure. The circular form allows support of the girder with six slender steel columns at mid axis. The slab dimensions of the bridge are kept constant to achieve an overall unity. The transition from the T-beam girder to the shear wall is continuous. Details are given of the bridge design, the columns, durability and robustness, handrail, protecting flashing and staircase tower. Details are given of the owner, designer, contractor, costs and service date.

A new cable-stayed bridge over the Grijalva river at Tabasco in Mexico is described. The single-span bridge was designed to carry two carriageways and one footway. The bridge is extended by two approaches on either side, each made of four spans. The total bridge length is 391 m. The platform width is only 13.8 m. The Tabasco region has a high seismic risk. The stiffness of the towers allows the longitudinal forces produced by earthquakes to be resisted by a single pier. The bridge was longitudinally fastened at one tower only. The deck is made of two longitudinal girders connected by strut diaphragms and by the top slab. The towers open in a V-shape in the bridge elevation and close in an A shape in the transverse plane. The stays have three alignments due to the V-shape of the tower. The bridge was built by free cast in situ cantilevers using form travellers, advancing symmetrically from each tower. Details are given of the owner, designer, contractor, costs and service date.

The Guama Bridge crosses the Rio Guama in the State of Para in Brazil. It is almost 2 km in length and includes two approach viaducts and a central three-span cable stayed bridge. Decks are composed of precast prestressed concrete girders with I-shaped cross sections connected by transverse beams and supporting a top concrete slab. The girders were prefabricated at the job-site plant and transported by barges before being lifted and installed by launching gantries. Details are given of the design, the aerodynamics of the bridge and the bridge construction. The problems posed by the initial inaccessibility of the site by road and by high tides and strong currents are discussed. Details are given of the owner, designer, contractor, costs and service date.

A pedestrian bridge built to span a dual carriageway and link a residential community with a recreational riverside pathway is described. The 122-m bridge is suitable for wheelchair and bicycle use. It has a soft S-shaped horizontal alignment, curvilinear corners and split-fork ramps, and consists of 11 spans of cast-in-situ reinforced concrete. Shaping details and the aesthetics of the bridge are described. Each pier is supported by two bearings one of which is a free-movement bearing, except at three sites where two free-movement bearings were installed. The stresses in the reinforcement were kept low in order to control the size of cracks in the reinforced concrete structure.

The new Carquinez Strait bridge in California with a total length of 1060m and a major span of 728m is the first major suspension bridge to be built in North America in over thirty years. It incorporates the latest in seismic analysis, foundation design and a state-of-the-art steel orthotropic box girder superstructure. The 1927 bridge was replaced mainly because of modern seismic resistance requirements. The bridge is situated in one of the most active seismic regions in the world. In an extreme event, the bridge should suffer only repairable damage. The superstructure is welded continuously from one end to the other, and is isolated from the towers using only rocker links for supports. These rocker links allow the box girder to swing freely between the tower legs, reducing interaction between the towers and the orthotropic box girder. Because of variable geology including soft clays, claystones, shale and fractured claystones and sandstones, the tower foundations were constructed of groups of twelve piles, each consisting of 3-m diameter reinforced concrete piles cast in driven steel shells. Details of the bridge deck are given.

This paper analyses the design of the Normandie Bridge across the Seine Estuary in France, and reviews the experience gained in its construction. It is the first cable-stayed bridge to have very long spans; in this case its 865m main span is the world's longest cable- stayed span. It is specially designed to withstand high winds, because of: (1) its carefully designed reinforced concrete and steel composite deck, which has a streamlined cross section; (2) its Y- shaped pylons; and (3) its high torsional rigidity. Its use of high- performance concrete has great structural advantages. The erection of access spans on both banks of the estuary required the contractors to develop a new technology, the 'staircase' method for horizontal span launching. Such a procedure was made possible by the use of a series of sensors, and a central micro-computer, to control horizontal and vertical movements. The balanced cantilever method was used to erect the central part of the bridge. A new type of cable was used, and interconnecting ropes were used to reduce the cables' vibration periods. The design engineers were given total responsibility for the design, so that they could introduce improvements at each stage of the project.

The new high-speed railway line Hannover-Wurzburg and its connection to the existing trunk line Wurzburg-Aschaffenburg crosses the Valley of the Main River at Gemunden, Veitshochheim and Nantenbach...

The Vihantasalmi Bridge is situated in Mantyharju, about 180 km north of Helsinki. The new bridge was planned to replace an old and narrow tied-arch steel bridge in beautiful scenery, where the roa...

The construction of a new motorway between Weil am Rhein, Germany, and Schaffhausen, Switzerland, required an overpass for pedestrians and cyclists near Rheinfelden. This article describes the design and, briefly, the construction of the bridge. The footbridge is a frame bridge with effective spans of lengths 14.85m, 30.30m, and 18.35m; its clearance above the motorway is at least 6.26m, and the width between its railings is 2.60m. The bridge length was chosen to obtain a good balance between design and economic efficiency. Two columns of glued laminated timber provide the central supports for the superstructure, which was planned as a vertically glued T-beam web of glued laminated girders. The exposed concrete surfaces of the abutments were scrubbed to make them look like wood. The bridge was planned as a wooden structure to blend with the surrounding landscape and local traditions. German codes for seismic design of buildings were applied. The superstructure is drained via a turned transverse gradient down to the lower abutment. It is covered with a four-layer deck of mastic asphalt. The article also describes the bridge's waterproofing, joints, protection against corrosion, load-bearing system, wood-preservation method, and erection.

In November 1995 the design-built contract for the ∅resund Bridge was awarded to Sundlink. The bridge contract includes: a 558-m long viaduct bridge on the artificial island; two approach bridges o...

In November 1995, the design-build contract for the Oresund Bridge, in the Oresund Link between Denmark and Sweden, was awarded to Sundlink [See earlier abstract, IRRD E100923]. The 7485m-long bridge consists of two approach bridges and one high bridge. It is a two-level structure with an upper concrete road deck on steel trusses and a lower concrete deck for the railway. Various concepts for lifting, transporting, and placing heavy bridge elements were studied during tendering in 1995. In 1996, it became evident that the heavy lift vessel Svanen would be ready for use in Summer 1997, which would fit very well into the overall time schedule for the Oresund project. As a result, it was possible to increase the sizes of the concrete elements forming the superstructure and to handle fully equipped superstructure elements. Concrete caissons, pier shafts, and troughs for the railway deck of the approach bridges were prefabricated at Malmo North Harbour. The two pylon caissons of the high bridge were much too heavy to be handled by Svanen, so that they were produced in a dry dock near the bridge site. All the approach caissons were founded directly on limestone below. Both approach and pylon caissons were placed on concrete support pads grouted on the limestone. The eight girders for the high bridge were made in Sweden.

The Taggenbrunn bridge is in fact two bridges of the same shape, the first erected in 1905, the second in 1911. In keeping with the existing bridges, two separate structures have been designed, one for each track. The are continuous composite girders, two girders for each bridge.

This article describes the design and construction of the Igelsta Bridge near Stockholm, which will be one of the largest railway bridges in Europe. It will carry both heavy freight trains and light high-speed passenger trains of up to 250kph. It will cross a large navigable channel about 49m above water level, a harbour area, and a highway. For most of its length, it will be a double-track bridge, but it will branch into two single-track bridges near the new railway station to be built at its south end. Above the channel, there is a balanced cantilevered three-span structure of post-tensioned concrete, with span lengths 90m, 158m and 90m. Over land, the bridge is also made of post-tensioned concrete, with cast spans each about 62m long. The double-track bridge has 33 spans altogether. The bridge is designed to withstand ship collisions. The bridges over land are founded directly on rock or on concrete piles. Over water, piles driven from a pontoon are used. The superstructures are box girders. The station has two 375m long platforms, located between the double-track bridge and the two single-track bridges. The double-track bridge is 2,070m long and 12m wide; the single-track bridges are each 714m long and 7.5m wide.

The Wuhu Yangtze River Bridge is a combined rail and highway bridge with a double-deck carrying two railway tracks and four lanes of traffic. The length of the bridge is 2194 m, comprised of steel trusses with a main cable-stayed bridge. The main span is 312 m and the side spans are 180 m long. Eight pairs of parallel-wire stay cables are mounted on each pylon and horizontal longitudinal cables are arranged between the steel girder and the crossbeams between the two pylon legs on top of the piers. The bridge dimensions were governed by navigation clearance to an adjacent airport as well as hydrology and geology. A stiffening truss was used to improve the vertical stiffness of the bridge. The reinforced concrete roadway deck slab was combined compositely with the steel truss to make them work together to improve vertical and lateral stiffness. The prefabrication of the reinforced concrete slabs, and the fabrication and erection of the steel truss are described.

The Jiangyin Tangtze suspension bridge is located at the Yangtze River Delta in China. The bridge is China's longest span suspension bridge with a main span of 1385 m. Construction started in 1994 and the bridge was opened to traffic in 1999. The bridge has six traffic lanes and the height clearance for navigation is 50 m. The bridge is said to look like a jade-studded belt flying over the river. The main bridge is made of flat streamlined steel box girders joined by prestressed continuous concrete girders. The south tower is a gravity structure built on bedrock. On the north bank, a gravity structure for the anchor was selected together with a deeply embedded caisson. The construction of the anchorage is described. The main cables are made of parallel high-strength wires and were erected using the parallel wire strand method. The stiffening girders are made of rectangular steel boxes and were erected from cranes fixed to the main cables.

In 1988, J Mathivat introduced the concept of 'extradosed' bridges, whose stay cables are functionally similar to external post-tensioning cables. The Tsukuhara Bridge near Kobe, Japan, is the second bridge where the Japan Public Highway Corporation has used this technique. It was originally planned as an arch bridge, but its design was changed because of the success of the Odawara Blueway Bridge, Japan's first extradosed bridge. Good seismic quality was another important consideration. The Tsukuhara Bridge is a three-span frame structure with a 180m long main span. Concrete counterweights inside the side span box girders reduce the piers' overturning moment. The bridge has single-cell box girders instead of conventional two-cell girders. A finite element analysis was conducted during the design process, to ensure durability like that of a traditional prestressed concrete slab deck with a 6m span. The piers and towers are V-shaped, and cross beams between the pylons are not necessary because the towers are short enough. The stay cables form a replaceable external cable system. The bridge was designed according to new seismic specifications, based on the 1995 earthquake at Kobe, because detailed design began after that earthquake. The girders are constructed by free cantilevering.

The Qi Ao road bridge, now being constructed, will be part of a highway linking Hong Kong with two other Chinese cities at the mouth of the Pearl River in China. It is 1267m long, and its main span is a multi-cable-stayed prestressed concrete box girder structure with a single semi-harp cable plane. The approach spans on both sides are continuous prestressed concrete girders with twin parallel single-cell box decks. The bridge deck curves with a 12km radius, and is 33m wide; it contains six traffic lanes, two footways, and one separation zone. The towers rise to 76m above deck level, and are designed as rectangular sections with variable outer dimensions. The stay cables are anchored to the towers' prestressed concrete walls, which are being cast in situ. The bridge deck is rigidly connected to the towers and piers. The design wind speeds of the bridge are 43.4m/s during construction and 62m/s during its working life; the seismic design allows for a peak ground acceleration of 0.10-0.25g. Aero-elasticity tests were conducted on a 1:100 scale model in a wind tunnel, to evaluate the bridge's aerodynamic behaviour during construction and in service. During construction, double cantilevers and 44 pairs of stay cables will be installed.

The Yong Jong Grand Bridge in South Korea is part of the new road and rail links between Seoul and the new Inchon International Airport now being constructed. The main design principles of the bridge were function, symbolic expression of Korean culture, and visual harmony with the surrounding environment. The 4.42km long bridge has an upper deck carrying a six-lane highway, and a lower deck carrying a four-lane highway and two railway lines. The main part of the bridge is its 550m long suspension bridge, with 300m main span, two 125m side spans, and a 60m cable sag. It is one of the few self-anchored suspension bridges that have yet been built. It has 35m clearance above the sea, steel box girders for its decks, and 104m diamond-shaped steel towers, whose wind-resistance properties were tested using a 1:150 scale model. The main cables are shaped in three dimensions. The bridge's design wind speed is 40m/s. The approach viaducts have a double-deck truss configuration with three-span continuous sections; each span is 125m long and 36.1m wide. The whole superstructure, which is almost all made of steel, is being constructed on steel bents. Cables will be erected on top of the superstructure, which they will then support. By April 1998, about 40% of the construction work had been completed.

The Ki-no-kakehashi Bridge is a timber road bridge with a stress-laminated deck, and is located on a forest road in Nagano Prefecture in northern Japan. It is 40.4m long, and has four 100m spans carrying two traffic lanes on its continuous deck. Its width including one walkway is 9.1m, and its depth varies stepwise from 540mm to 560mm to 585mm. Cross beams, 1400mm wide and 840mm deep, directly support the deck. 26mm diameter high-strength steel prestressing rods are spaced about 1m along the length of the bridge. The 30m long Midoribashi Bridge is located on the same forest road, and has a two-hinged rigid timber frame with spans of 9m, 12m, and 9m. A bridge without piers was desirable, and a rigid frame structural scheme was selected. The glulam curved and tapered rigid frames are the bridge's main members, and jointed at span centres with the same type of mechanical joints for stringers. All joining work was conducted at the bridge site. To optimise load distribution, the glulam cross beams were also attached between the stringers and the rigid frames. The rigid frames, longitudinal stringers, and cross beams were assembled by prestressing the 32mm diameter bars, and inserted through pre-drilled holes in the cross beams.

This article describes the design, analysis and construction of a widened road bridge in Germany. The previous bridge, using a solidweb girder method of construction, was considered historically important and so incorporated to the new structure. A new single-cell, externally prestressed box section was designed to form a new superstructure alongside the existing bridge, built on tapering pier slabs. Its cantilever arm was positioned over the load-bearing structure of the existing bridge to reduce non-functional excess width. Structural design of load-bearing characteristics used a bond between the deck slab and inner main girders. A stability analysis was carried out to provide a sufficient load-bearing capacity: stud bolts were fitted near the reinforced concrete joists on the inner main girder and near the cross girders, to secure location and transfer shear forces. Fracture mechanics analysis was used to predict the damage tolerance of the structure and reinforcement was carried out on the inner main girder.

(2005). Bridge over the Corgo River Valley. Structural Engineering International: Vol. 15, No. 2, pp. 88-88.

The Rion Antirion Bridge in Greece consists of a main bridge, 2252 m long and 27.20 m wide with two approaches one on each side of the Corinth Strait. The environment consists of deep water, deep soil strata consisting of weak alluvium and strong seismic activity. The bridge had to accommodate possible fault movements and the impact of a big tanker moving at a speed of 30 km/h. The bridge design consists of a cable-stayed bridge made of 3 central spans and 2 side spans with four pylons resting on concrete substructure foundations. The deck is a composite steel-concrete structure. The design phase of the project is outlined with reference to the foundations and soil reinforcement, analyses and behaviour of reinforced soil, dynamic analysis of the bridge, the behaviour of the structure, and the push-over analyses of pylons. The construction of the pylon bases, foundations and tension leg platform, upper part of the pylons, and deck are described. The bridge was completed in August 2004.

This paper describes the rehabilitation of the John Mack Bridge across the Big Arkansas River in Wichita, KS, USA, built in 1929. The 243.8m long eight-span bridge has composite steel and concrete tied arches, each 30.5m long and rising above the deck at the kerb line. At the core of each arch rib is a steel arch lattice work. The arch ribs consist of four steel angles, embedded in 760mm x 1000mm deep concrete. The bridge is generally in good condition, but the concrete casings of the steel arch hangers showed extensive cracking, with cracks up to 3mm wide. The bridge was analysed as a three-dimensional structure, using a finite element model. The analysis revealed the presence of bending moments transverse to the arch hangers; when combined with the tensile loads, the bending moments significantly increased the stresses in the hanger steel. There was also a diagnostic load test, using a pre-weighted test vehicle at various positions on the bridge. The strains, induced in the concrete and steel, were measured. The bridge was found to have a structural capacity far beyond its requirements, so that the only repairs necessary were to the hangers; 35mm diameter full-height high-strength rods will be attached to all hangers.