Loading vehicle
Loading vehicles are generally called vehicles that are used to test bridges (e.g. Leopard 2 tanks ). Basically because of the danger at the crossing of heavy vehicles that the structure is damaged, a special vehicle that was used for the risk-free testing Bel astungs fa hrzeug BELFA developed.
development
A research cooperation between the University of Bremen (project management), TU Dresden , HTWK Leipzig and Bauhaus University Weimar researched the scientific basis for experimental structural safety assessments in the field of structural engineering and bridge construction in two projects funded by the Federal Ministry of Education and Research (BMBF) from 1989. Among other things, this resulted in the DAfStb guideline for load tests on concrete structures. In order to be able to test road bridges more efficiently, the research cooperation from 1999 to 2002 dealt with the development of the BELFA, also funded by the BMBF. The aim was to develop a system that, in contrast to previous testing technology, can be used quickly and flexibly, does not require long closures and does not need to intervene in the structural sealing. After several iteration steps, the final concept of the BELFA was in place: a semitrailer for examining bridges, ideally up to 18 m span and a maximum test load of 1500 kN. This allows the usual bridge classes to be checked. This vehicle is unique in the world. After the construction and testing of the device, the first use took place in 2001 on a road bridge in Neu Kaliss , Mecklenburg-Western Pomerania. The loading vehicle has been in use for the Leipzig Materials Testing Institute (MFPA Leipzig GmbH) since 2015 .
technical description
vehicle
BELFA is a semitrailer with a 4-axle heavy-duty tractor unit and a 5-axle semitrailer , which is equipped with hydraulic forced steering. In the transport state it is approx. 22.50 m long, 2.75 m wide and has a total towing weight of approx. 80 t. For driving on public roads, a permit according to § 29 Paragraph 3 of the Road Traffic Regulations (Germany) and an escort vehicle BF 3 are required. The manufacturer's designation of the semi-trailer is SX 50 ZEL.
Testing system
The heart of the BELFA is a hydraulic system that is usually used in materials testing machines. The control cabin, hydraulic pumps and a generator are located at the rear of the vehicle. 5 hydraulic cylinders with load application traverses (so-called test traverses) can be moved in any lengthwise direction in order to introduce the loads on the structure in a controllable manner.
function
Before the BELFA is brought into the test position, the front part of the vehicle must be telescoped. The tractor then pulls the vehicle over the structure to be examined, with the heavy 5-axle rear carriage remaining in front of the structure. Once the test position has been reached, the supports are pushed over the abutments or pillars and extended so that the part of the structure to be examined is load-free. With the loading crane of the BELFA 6 steel weights are placed anywhere on the vehicle in order to adjust its center of gravity to the test task. By adding up to 40 t of additional ballast, it is possible to further increase the available test load. Finally, the test traverses are moved to the points on the structure that have been previously determined by a pre-calculation.
Operational experience
To date, the device has been used in test loads on 2 special sewage structures and 45 bridges with a total of 85 fields in Germany and abroad. Helpful insights and, in some cases, astonishing results could be obtained: some ailing-looking bridge has a healthier interior and is much more resilient than initially assumed. Often even a higher bridge class could be recommended. It was irrelevant whether the evidence included all bridge elements (superstructure, support and abutment as well as foundation), which supporting structure was present (plate, girder grating, vault) and what building material the structure was made of. In the summer of 2015, the Gustav Esche Bridge in Leipzig was tested for its load-bearing capacity with the aid of the loading vehicle.
Bergen (Lower Saxony) - 2009
Essen (OL) - 2011
Hanover - 2012
Leipzig - 2015
Leipzig - 2015
.jpg){kind=small}
Web links
Individual evidence
- ^ German Committee for Reinforced Concrete: Guideline for Load Tests on Concrete Structures. Beuth Verlag, September 2000
- ↑ Steffens, K. et al .: Development, construction and testing of a load vehicle (BELFA), cooperative research report 01RA 9901/0, final report, University of Bremen, self-published (2002)
- ↑ Bolle, G., Schacht, G., Marx, S .: Historical development and current practice of the test load. Bautechnik 87 (2010), H. 11, pp. 700-706 and H. 11, pp. 784-789
- ↑ Steffens, K. (Ed.): Experimental structural safety assessment of buildings: Fundamentals and application examples. Civil engineering practice, Berlin: Ernst & Sohn (2002).
- ↑ Gutermann, M .; Schröder, C .: 10 years BELFA loading vehicle. Origin, experiences and outlook. In: Bautechnik, Volume 88, Issue 3, Ernst & Sohn, March 2011, p. 200 f.
- ↑ Archive link ( Memento of the original dated November 1, 2016 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
