By the planned end of construction in 2021, a total of 300,000 m² of asphalt will have been paved at the Fürth/Erlangen interchange. Of this, 2.4 km is porous asphalt on the A3, and 2.3 km is low-noise stone mastic asphalt on the A73. For this construction project too, one of the largest traffic projects in Germany, Max Bögl is using state-of-the-art compaction technology from BOMAG.
The construction site at the Fürth/Erlangen interchange is part of the six-lane expansion project of the A3 between the motorway junction Biebelried near Würzburg and Fürth/Erlangen. The flyovers from the A3 onto the A73 from the direction of both Würzburg and Nuremberg will each be widened to two lanes to ensure a significantly better flow of traffic, particularly at peak times. For this the classic cloverleaf design will be replaced with two new constructions: the flyover and the underpass. After completion, traffic from Erlangen to Regensburg will be routed smoothly via the flyover without any merging or roundabouts. The dual-lane flyover will already begin at Bruck on the right, where it will then pass over the A3 in an elegant left curve to then enter an underpass under the A73 before both lanes merge into the many lanes heading towards Tennenlohe.
In order to further increase its own quality standards and efficiency while at the same time conserving resources, Max Bögl is testing two innovations that BOMAG presented at this year’s bauma trade fair. Max Bögl, a long-standing BOMAG customer, already relies on the market leader’s equipment for 80% of its fleet, and is also testing the BW 174 AP Hybrid with Asphalt Manager and BOMAP. The pivot-steered BW 174 AP AM Hybrid tandem roller is one of BOMAG’s answers to requirements to reduce energy consumption and emissions on the one hand, and to increase performance and efficiency on the other. Max Bögl has been relying on BOMAGprecision machines for quite some time; among others, the pivot-steered tandem rollers in combination with ASPHALT MANAGER. The oldest tandem roller in use in this infrastructure project is the 174 AP AM, built in 2007. This split-drum tandem roller is already equipped with the tried and tested ASPHALT MANAGER, which offers the selection of three exciter systems including oscillation.
BOMAG’s hybrid drive concept makes their machines quieter and more economical, and therefore more eco-friendly. In addition, the integrated hydraulic hybrid accumulator offers dynamically retrievable power storage to provide top performance on demand. It has the capacity to generate up to 100 Nm and 20 kW of additional power, which corresponds to a total output of 75 kW and thus the level of its conventional sister rollers. In push mode, the hydraulic accumulator is recharged without the use of external energy. The combination of optimised diesel engine, hydraulic accumulator, automatic compaction control (Asphalt Manager) and BOMAP, make the tandem rollers a highly-efficient solution, as can be seen on the construction site at the Fürth/Erlangen interchange.
The roller quartet consists of the tandem rollers BW 174 AP-4 AM, BW 174 AP AM, BW 154 ACP-4 AM and the BW 174 AP AM hybrid tandem roller. The hybrid roller has the same system performance as the conventional tandem rollers of the BW 174 series. However, the 75 kW are divided into the 55 kW diesel engine and the 20 kW hybrid accumulator. This reduces the fuel consumption of the hybrid model by about 20%, and the CO2 values drop accordingly. This is made possible by the integrated diesel engine which meets the limit values of emissions standard V. The combination of particulate filter, oxidation catalyst and a cooled exhaust gas recirculation system enables the BW 174 AP Hybrid to run without additives such as AdBlue. In addition, the roller drivers experience the hybrid model as considerably quieter and thus more pleasant when rolling.
BOMAP was developed by the compaction specialist BOMAG for roller drivers to support them in their responsible task in a practical and easy manner. This free app can be installed like any other app on mobile Android devices. The menu is intuitive and easy to understand just like most other apps, and who doesn’t use such useful “helpers” on their tablet PC or smartphone these days? The self-explanatory, mobile solution shows the roller operator the precise compaction passes being performed while driving in real time on the screen. This shows the driver areas that have already been compacted or still need to be compacted, and the roller's position on the road section. Thus, ensuring that no pass too many or too few is performed. The roller drivers are better able to manage their paving and working times, and the site's time management is supported effectively. In addition, less fuel is required, machine wear is reduced, and the work result is optimised. When the tablet with BOMAP installed is powered up, BOMAP connects to the machine interface and registers the machine parameters. The roller driver only has to add the required compaction passes and can then start directly. In other words, everything is just like the navigation systems that almost every motorist uses today.
The surface design with its easy-to-read colour scale is perfect for any compaction operation. Coloured areas show the corresponding compaction result and all the data is stored immediately and automatically. Max Bögl equipped the BOMAG tandem rollers in their fleet with tablet PCs with BOMAP installed in order to test the system in practice on the large construction site. For this test, the hybrid roller was additionally equipped with an external GPS receiver to obtain information about the precision of the machine’s movements. The separate GPS receiver was positioned on the roof of the driver's cabin by its magnet and then simply connected via Bluetooth to the tablet PC. For a direct comparison, a second tablet PC was installed in the hybrid tandem roller and located the machine’s position by means of the GPS receiver integrated in the PC. This method was also applied in the three other tandem rollers.
In the night from 14 to 15 July 2019, the field test was performed under completely normal paving conditions. Around 3,000 t of base course were installed in this night shift and compacted with the four tandem rollers. During the initial hours of testing – the measuring results were constantly monitored by the site manager and Max Bögl material planners, as well as the BOMAG product manager and regional sales manager – there was a significant deviation in the tandem rollers’ position location. The hybrid roller with an external GPS receiver was displayed with an accuracy of approx. 15 cm. The position determination via the GPS receiver in the tablet PC resulted in deviations of between 2 and 3 metres, thus providing only a rough orientation. From the outset, the four roller drivers had no problems starting BOMAP, connecting it to the machine interface and adding the few parameters manually. The visualisation of the work results in combination with the current roller position greatly helped the drivers in the long night shift because the “normal” visual orientation at night on the “black tarmac” is very exhausting and imprecise.
Comprehensive documentation and evaluation – a tablet PC with a SIM card and BOMAP installed – this is already sufficient for the “connected” construction site. And to make it even easier and more transparent for all parties involved in the construction process, as well as to provide safer documentation, BOMAG will soon launch its cloud solution. This will provide outstanding advantages for users, such as the real-time integration of a paver, which will send its track as parameters to the rollers in conjunction with the mix temperature. As a result, all the drivers of the connected construction machines deployed have an overview of the complete project and/or the current construction phase. No additional hardware or dongle etc. is required for this connected overview, which results in maximum simplicity and functional reliability, and reduces set-up times to zero. A further advantage is that no additional software is required, because the entire application runs in the web browser. The numerous interfaces for data import and export ensure the seamless connection and cooperation of all those involved in the construction site by sharing drawing-, measurement-, and compaction data. This, in turn, enables unlimited documentation and analyses. With the complete BOMAP package, the connected construction site 5.0. is a working reality.