A New Bridge over A22 and Adige River in Salorno, Italy

Bridge superstructure design final year., 2017

In general a bridge project can be considered to have three major stages. They are, 1. Investigation stage 2. Design stage & 3. Construction stage Unlike the building structure constructions, bridge projects require an intensive investigation based on the feasibility, requirement or necessity, population benefited, economic development expected, topography, hydraulic data and soil characteristics prior to the approval and design stages. After all such investigations being over, the design stage commences. The design stage, consists of mainly three elements; hydraulic design, geometric design and structural design. Hydraulic design accounts for calculation of flood discharge, scour action near the bridge supporting structures, characteristics of river channel to fix the level of the bridge, clear water way of the bridge and thus the bridge spans. Foundation depth based on hydraulic characteristics is also a point to be considered. In geometric design, vertical and horizontal alignment and curvatures required are to be established. Traffic flow characteristics, projected traffic over one or two decades are to be considered. Thus the geometric design concerns more with transportation engineering point of view. Structural design involves the selection of component types and providing an economical solution for the purpose intended based on strength and serviceability point of view. At the end of design stage estimations, drawings and approvals are vital roles to be performed. At the construction stage, one cannot start the construction of bridge all of a sudden without certain preparatory works. Apart from primary construction surveys, river training works, coffer dam construction, approaches for machinery and equipments, storage and security for materials are important elements of bridge project under construction stage. Material and manpower management are also vital tasks for construction managers at this stage. There are design specific and bridge type specific construction technologies that could be adopted at this stage (like slip form, cantilever form techniques etc.). 2.3 DESIGN OBJECTIVES The general objective of bridge design is to provide economic, viable and safe solution to cross an obstacle such as river, valley and other traffic flow, by means of proper selection of site, material, type, technology and design. Specific objectives can be listed as follows: 1. to provide economic, strong and durable design of bridge 2. to provide the shortest structure across the obstacle 3. to forecast and decide the expected traffic flow in the future decades to come and to finalize the structural dimensions 4. to study the hydraulic data and fix economic spans for the bridge superstructure 5. to include applicable load combinations to design the structural components with the help of appropriate design code DESIGN WORKING LIFE Concrete, stone and steel bridges shall be designed for 100 years working life. Concrete and Steel culverts with an opening or diameter less than 2.0 m and all timber bridges shall be designed for 50 years working life.

Handbook of International Bridge Engineering, 2013

The project includes a cable-stayed bridge and two approach viaducts: one on the Chaco side on National Route 16 and another one on the Corrientes side on National Route 12 (Figure 3.22). Those structures are 2000 m long (1666 m over water) and 8.3 m wide, with one lane in each direction. The vertical navigation clearance is 35 m. The required horizontal clearance is 200 m. The cable-stayed bridge comprises three spans (163 m + 245 m + 163 m). It is composed of two 225 m long suspended structures, placed symmetrically along the main pylons axes, which are 245 m apart. A simply supported span of 20 m links these two structures to form the main span of 245 m. This suspended span reduces the effect of deflections on the two main structures. Each main pylon is a W-shaped frame that rests on a pile cap for its foundation. A set of eight stays completes each main 83 m high pylon. The cross section is a two-box girder. The deck is completed with precast transverse slabs, 6.9 m long and 2 m wide, supported on the main beams. When the deck was finished, the transverse beams were prestressed. The original stays were of the locked coil type, but they had to be replaced after 25 years of service. The longitudinal beams of 3.5 m deep were prestressed. The approach viaducts over the river are composed of nine spans of 82.6 m each on the Chaco side, and three spans of 82.6 m each on the Corrientes side. They were built by the balanced cantilever method with precast segments 4.1 m long and 2 m deep at center span and 4.5 m deep over the supports. The overall deck width is 11.3 m, carrying two 3.65 m wide lanes, narrow emergency shoulders of 0.50 m and pedestrian sidewalks 1.5 m wide. The piers of the approach viaducts are constant deep box sections and were built by the sliding formwork method. The foundations were made using 1.8 m diameter bored piles with variable lengths between 38 m and 60 m, and with preloading cells, they are clamped by penetration into the hard clay stratum. At around 20 years of service, the replacement of all the stays was required. Construction works were carried out by Freyssinet SA (Spain) in 1995. Parallel strands stays were installed. The link between both cities, with only two lanes, has proven to be insufficient for the traffic, which has been ever-growing since its construction. The construction of a new bridge is now under consideration. Construction work began in August of 1968 by the initiative of the governments of the provinces involved: Corrientes, Chaco, and Formosa. The owner was DNV, who called for international bids in 1965.

A highway structure is a structure intended to carry highway vehicles, and/or bicycles and pedestrians over, under or through a physical obstruction or hazard, and may be a bridge (which may be in the form of a culvert exceeding 2 m in diameter or span), a flyover, a viaduct, an underpass, a subway, a walkway cover, a cantilever noise barrier, a noise enclosure or a sign gantry.

E3S Web of Conferences, 2019

This article describes technical problems concerning bridges, dangers that arise when the bottom of the river bed is lowered during the liquidation of the floodplains. These floodplains arise as a result of terrain subsidence caused by mining exploitation. In urban areas with developed building and road infrastructure, bayous can cause significant social and material damages. One of manners of the floodplain liquidation or long-lasting lowering the water table is lowering the bottom of river channel on the leakage from bayou. Lowering the river channel can concern the section of few kilometres even long. Lowering the riverbed by dredging or considerable deepening generally does not cause important problems. Significant technical problems are generated by bridge objects. In the case of bridges, it is necessary to ensure the stability of bridgeheads, protect foundations from washing away and undermining. It is necessary to design channel reinforcement so that significant horizontal fo...

Geomechanics and Tunnelling, 2017

As part of the Stuttgart 21 infrastructure project, German Railways is building a four-line railway bridge across the River Neckar in Stuttgart, work started in 2016. The Neckar railway bridge has an overall length of 345 m and has two abutments and six support axes. The structure crosses rail lines from the urban transit (Stadtbahn), the main trunk road B 10, inner city roads, the Neckar River, pedestrian and cycle ways as well as diverse public and private utilities. The bridge structure is located within the core mineral water protection zone, with its strict restrictions regarding the permissible depth of penetration into the subsoil and groundwater reservoirs. The mineral water springs lie within the construction site 26 m below the surface as artesian aquifers with an artesian pressure of ca. 10 m above ground level. From a groundwater management perspective, and following a program of five ground investigations and their evaluation, a raft foundation at the mid-level of the lower Keuper, built using cut-and-cover technique with a compressed air caisson, was chosen as the most economical foundation type for the three primary supports. A further programme of hydrochemical and geomechanical ground investigations was undertaken during the construction design phase. Following an evaluation of these additional ground parameters, it was possible to replace the compressed air caisson with a more economical deep foundation using large diameter piles. A management concept for possible scenarios was needed for the large diameter pile construction to achieve the required consent for exceptions from the ban on ground penetration in the area of the mineral springs.

2014

Seismic retrofitting of existing bridges, aimed at enhancing their safety level under earthquake conditions according to current design standards, is often a challenging task. When designing the strategy for seismic retrofitting, in fact, the practitioner have often to face remarkable limitations to the possible interventions, mostly due to the geometry of the original structures and to construction site accessibility issues. A meaningful example of this task is represented by the concrete bridge over the Tanaro and Bormida rivers of the A21 Italian highway between the cities of Turin, Alessandria and Piacenza, managed by Satap S.p.A in Turin. The overall bridge is characterized, in fact, by three different structural types consisting of: (a) a box girder deck, (b) a deck supported by regular r.c. beams and (c) a deck supported by p.c. beams. The analysis of the seismic vulnerability of the bridge in its „as-built‟ configuration has been carried out according to the current Italian ...

The project proposal is about the Reinforced Concrete Maluos Bridge situated along the Bukidnon-Davao City Road at Kabalansihan, Kitaotao, Bukidnon. The said project is designed using the analysis for reinforced concrete. Certain parameters for the reinforced concrete structure has been considered in order to attain the objectives formulated in the project for better results. Accordingly, the factors and parametric awareness that may affect the integrity of the bridge was considered. The elements of the bridge, the materials and its corresponding properties, the different types of loading including impact, and the different design assumptions has been rigorously considered. Portland cement, coarse and fine aggregates, water, admixtures, and deformed bars are materials that made up the reinforced concrete has been identified and defined according to its properties and specifications as base on theoretical codes. Compressive and tensile strength, stress-strain curve, Modulus of Elasticity, creep and shrinkage, and quality control of both concrete and the reinforcing bars were further elaborated. Next, the strength design method, NSCP designs assumptions and safety provisions, loads and load combinations as based on AASHTO and NSCP, and software programs used in the calculations and design were discussed thoroughly. Under the plans and specifications were the architectural and structural drawings which were shown. Such architectural drawings includes the top view, general elevation, and isometric view of the bridge while on the structural drawings includes the detailed drawings of the beam, slab, barriers, and footings. Followed by the plans and specifications are the results and discussion of the project. This is where the important parameters and factors in the analysis and assumptions of the design was discussed. After the analysis is the conclusion and recommendation for the project. The bridge is designed to support an MS18 (H20-44) vehicle. The bridge is composed of eight reinforced concrete beam/girder with a dimension of 350mm x 620mm. Beams located on both ends, supporting sidewalk live loadings, has 5-25mm reinforcements, while beams supporting the roadway has 11-25mm reinforcements. Moreover, it is composed of a 200mm-thick slab with a 125mmthick wearing course made of asphalt. Lastly, a spread footing with a dimension of 9.54m by 3.5m with a thickness 600mm and with a 25mm diameter reinforced bars has been designed. More detailed and elaborated results are presented in Chapter 5.

2015

In our country where many rivers run dry after the end of monsoon, it is a need of the day to block the post monsoon flow for drinking, irrigation etc purposes. Bridge cum Bandhara (BCB) system is a dual purpose bridge structure which fulfills both crossing as well as water retaining motives. This paper emphasizes the analysis and design of different type plans of Bandhara system for different soil strata. Design forces are taken for Bandhara piers using IRC: 6-2010 and stability of structure is checked against overturning, sliding, uplift and for maximum and minimum pressures at the base. A parametric study is carried out to decide optimum dimensions of Bandhara piers for various heights of retained water. Moreover quantities are estimated for all the type plans and compared. The study reveals that with the judicial optimum design, the cost of BCB would be well within financial norms depending upon the storage on U/S side.