Liebherr rotary drilling rig LB 24 with Kelly drilling application is being used for bridge construction in Dingolfing-Landau, Germany.The German district of Dingolfing-Landau, represented by the Department of Civil Engineering from the Dingolfing District Office, has planned and invited tenders for the construction of the Isar bridge Mamming, which is to be built as part of the district road DGF 11 near Mamming. The new bridge replaces the existing bridge dating back to 1954. The construction work is due to be carried out between September 2010 and August 2011. The total costs of the project including the demolition of the existing bridge are estimated at Euro 3.3 million. The company STG Spezialtiefbau GmbH was engaged to carry out the deep foundation and lining work and chose a Liebherr LB 24 rotary drilling rig for installing large-diameter drilled piles.The old bridge features a limited load-bearing capacity and would have required an expensive general refurbishment. In order to avoid traffic hold-ups, it was decided to build the new bridge west of the existing bridge and to adapt the course of the road for a length of about 500 m. The new bridge was planned as a pre-stressed concrete bridge with a total span of 105 m and a width of 12.25 m between the railings. At both ends of the superstructure box-shaped abutments made of concrete are placed on a deep foundation. The foundation consists of a total of 13 drilled piles with 90 cm diameter which were partly installed at an angle of 10:1. The massive supports are based on a combined structure of drilled piles and steel casings. A special method was chosen to install the piles in the bed of the Isar river. The drilled piles of 120 cm diameter with casing were installed by the Liebherr rotary drilling rig LB 24 from a jack-up barge.The work in Dingolfing was carried out using a casing oscillator which was driven by the on-board hydraulics of the Liebherr rotary drilling rig.During this building project the LB 24 achieved a final depth of 20 m, 10 m of which were embedded in the ground. Thus, it was possible to concrete the pile over and above the water level and to extract the casing with the aid of the casing oscillator. The Liebherr rotary drilling rig LB 24 installed three piles for each of the four supports in the river. In order to finally cover the drilled piles, a precast reinforced concrete section reaching down below the water level was placed over the top of the piles and connected them using cast-in-place concrete. Thus, a working platform above the water level was created.The LB series offers an ideal addition to the existing range of combined piling and drilling rigs of the LRB series. The design of the LB series is based on Liebherr's many years of experience with deep foundation applications and considers even the heaviest demands, which are nowadays made on modern rotary drilling rigs. The machines in the LB series have been designed for Kelly drilling, continuous flight auger drilling, double rotary drilling and soil mixing applications.The new LB 24 rotary drilling rig is compact and is therefore predestined for operation in limited spaces. Basic machine and leader can be transported in one piece. Leader top and leader bottom are foldable. Its minimum clearance and transport width is a mere 3.39 m. This allows for quick and easy transportation of the rig and thus for flexibility in jobsite assignment. The rig has been designed for drilling diameters of up to 1.9 m and drilling depths of up to 40 m.A significant advantage of the LB 24 is the rope crowd system with 20 t pull force. This provides the operator with maximum performance and reliability even with the most difficult soils and extreme operational conditions. A unique technical feature of the LB 24 is the solid design of the leader as well as the extremely robust kinematics with large cross section.The LB 24 is equipped with the proven Litronic control system which is based on a CANBUS system of the latest generation. This control system does not only include programmes for the application of the various drilling methods but also provides clear information on service requirements and possible defaults. A modem for remote diagnosis as well as a process data recording system for documentation of the work carried out are available as cartridge.Furthermore, the rig's drive system excels in a remarkably low fuel consumption. The unit is fitted with a 270-kW Liebherr diesel engine which consumes much less fuel than comparable competitors' machines.The multitude of proven Liebherr components used play an important part in the operational reliability of all machines in the LB series. Moreover, the close network of international Liebherr service stations ensures excellent availability in case of a failure or for maintenance work.