Get Adobe Flash player

DLT

PDR-system used for special bridge project in Cartagena, Colombia

 

For the highway from Cartagena to Barranquila, Colombia, the approx. 6 km long bridge “Viaducto Gran Manglar” is built just north of Cartagena through a shallow lagoon with mangroves.

 

Mangroves are protected vegetation and therefore a construction method with minimal environmental impact was required. The contract was awarded to the Italian contractor Rizzani de Eccher who proposed to build the bridge from a launching gantry, using precast concrete elements.

 

Picture 1

Picture 1

Picture 2

Picture 2

This very special construction method – developed by Canadian piling & equipment company Berminghammer - has a minimal impact on the surroundings, because the footprint of the construction work is the same as for the bridge itself: the gantry rests on the front end of the already completed part of the bridge and cantilevers to the location of the next pier. At the front of the gantry the piles for the next pier are installed, while at the back the main girders of the bridge deck are installed. These girders (just as all other construction materials) are transported over the already completed part of the bridge instead of through the lagoon, further reducing the environmental impact.

Picture 3

Picture 3

Essential for this construction method is the verification of the foundation piles’ bearing capacity for each of the 129 piers within hours after installation, because the piles will have to bear their maximum design load 72 hours after driving. For this reason Rizaani chose to purchase Allnamics PDR-systems and AllWave software, and have their staff trained on site by Allnamics. This enabled Rizzani to perform PDA and subsequent signal matching themselves, with Allnamcis support (both on site & remote). Rizzani also contracted Allnamics to perform the dynamic monitoring of the test piles and the development and implementation of the pile driving and acceptance criteria.

Picture 4

Picture 4

The construction method with the launching gantry allows the entire bridge to be built with precast pre-stressed concrete elements. For production of these elements – piles, pier caps and bridge girders – a complete precast yard has been built next to the northern abutment of the bridge. All elements are then transported to the rear of the gantry, using the already constructed part of the bridge.

 

Picture 5

Picture 5

Picture 6

Picture 6

The launching gantry consists of 2 parallel truss bridges, and  rests on 2 main support beams that are placed on already installed piers.  From there the gantry cantilevers approx. 50 m, just past the loacation of the next pier.  Running over the top of the gantry are 2 cranes and at the front there is a leader system, equipped with a Berminghammer B6505-HD diesel hammer.

Picture 7

Picture 7

The hollow concrete piles with a diameter of 1,0 m and a length of up to 55 m are driven in 2 sections that are jointed together with a custom designed mechanical splice . The cranes move the pile sections from the rear to the front of the gantry where it is placed into the leader. Next the leader  is erected vertically, after which the pile section is driven. Once the pile section is installed the leader is lowered back to the horizontal position sothe next pile section can be accepted.

Picture 8

Picture 8

 

Picture 9

Picture 9

Picture 10

Picture 10

Picture 11

Picture 11

After all 6 piles for the pier have been installed, they are cut off and a precast concrete cap is mounted over the pile heads. Once a temporary support is placed between this pile cap and the gantry, the front main support can be moved to this new pile cap and the rear main support is also moved up one pier. Then when both main supports are in their new position, the whole gantry is moved one span forward (approx. 37 m), with the leader ending up just past the location of the next pier to be constructed. But before the piles for that pier are driven , the girders for the bridge deck are mounted up to the just finished pier.

Picture 12

Picture 12

With the launching gantry working at its normal pace, this installation cycle takes 3 days. For that reason the piles will get their maximum design load after 72 hours, when the gantry with leader cantilevers just passed the freshly installed pier cap. In each cycle, the pile bearing capacity needs to be verified in time for that.

 

Rizzani started piling at the north end of the bridge in August 2016 and will soon start with a second gantry at the south end.

 

For dynamic pile monitoring on two fronts Rizzani has purchased a second PDR-system.

 

 

Video of Berminghammer.

 

Dynamic Pile Testing for Amstel Towers Hotel in Amsterdam

 

In April 2016 Allnamics has performed PDA-monitoring and DLT-testing for our client Voorbij Funderingstechniek BV, for the Amstel Towers Hotel near Amstel station in Amsterdam. The tests were done on 51 m long precast concrete piles, driven in sections, with a mechanical joint.

 

PDA monitoring (Pile Driving Analysis) was done during full installation cycles of selected production piles. Main goal of the test was to check the tensile stresses during driving, in particular at the location of the mechanical joint.

 

DLT-monitoring (Dynamic Load Testing) was done during restrike (approx. 10 blows) on piles that had been installed a couple of days earlier. Main goals of this test were to check the strength of pile shaft and joint and the static bearing capacity  of the pile.

 

Both tests were performed with the in-house developed Allnamics PDR-system, fitted with combined strain and acceleration sensors, which were mounted near the pile head. The PDR reads and stores the monitoring data real time and transmits them with a wireless connection (by WiFi) to the field computer of the monitoring engineer. The wireless connection offers great advantages during upending and positioning of the pile and makes it possible for the monitoring engineer to do his monitoring job on a good location, at a safe distance from the pile and without traditional worries about the long cable getting stuck or damaged during handling or piling.

AmstelTowersHotel_Foto_1

Photo 1 : Monitoring with WiFi connection, at a safe distance from the pile

The tests showed that the tension stresses during driving were acceptable and that the available static bearing capacity is sufficient for the design loads of the piles.

AmstelTowersHotel_Foto_2

Photo 2 : no trouble with long cables during upending of the pile

AmstelTowersHotel_Foto_3

Photo 3 : pile and monitoring equipment at end of PDA

Dynamic Foundation Measurement training for BAM International

Day 1 Theory First

 

In February 2015 Allnamics trained 6 staff members of BAM international in the use of the Allnamics’ PDR for proper data acquisition during Pile Driving Analysis and Dynamic Load Testing.

 

As usual the training started with a day in the Allnamics office to cover the theory, during which the trainees had to derive equations for the one-dimensional wave theory. For some this is pretty tough, but after this session participants always have a good idea of what happens in a pile as it is driven into the ground and they can not only interpret field measurements but also distinguish between good and bad data sets.

 

The second day was a field day. Thanks to the company Hektec all trainees had the opportunity to install sensors as well as connect and operate the equipment. This is important aspect of mastering the process, and with these sensors real data was then obtained during an actual hammer blow later in the day.

 

The third and final day was back in the office, during which not only the data collected the previous day were reviewed, but also many data sets from projects Allnamics performed over the years around the world.

 

Obviously the training does not necessarily end at the end of this third day when the participants leave with the course material. Allnamics staff is always available to support the course participants whenever they need some additional help.

 

If you want to know the participants’ take on the course click here to read their report on the BAM International website.

 

With the PDR data can be acquired to monitor the pile driving process but it can also be used during Static Load Testing (SLT) and Rapid Load Testing (RLT) of deep foundation elements.

 

If you need additional information on the PDR or a training course StatRapid, please feel free to contact us or download the PDR brochure.

 

Day 2 Dry Practice

Day 2 Dry Practice

 

Day 2 Overview test location

Day 2 Overview test location

 

Day 2 Two groups who can drill best

Day 2 Two groups who can drill best

Day 2 Sensor on the pile group 1

Day 2 Sensor on the pile group 1

6 BAM Day 2 Sensor on the pile group 2

Sensor on the pile group 2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Day 2 Examining the data

Day 2 Examining the data

 

Day 3 evaluating and understanding data

Day 3 evaluating and understanding data

Dynamic and Static measurements at 40 m waterdepth

Overview testlocation

Overview testlocation

 

To optimize and certify the final design of the Wikinger Offshore Wind Farm (OWF) in the Baltic Sea near the German island of Ruegen, the project owner, Iberdrola Renewables, initiated a test program, whereby test piles were installed at the planned location of 3 wind turbines in 40 meter deep water.

 

During the first phase the test piles were driven into the sea floor as Pile Driving Analysis (PDA) measurements were taken using underwater sensors. In addition signal matching was applied on the measurements during the final hammer blow to predict the mobilized static bearing capacity of each pile.

 

After a set-up period of approx. 13 weeks the second phase took place, during which at each location one test pile was subjected to a static tensile load test (up to 15 MN) while the other pile was subjected to a high strain dynamic test. For the latter signal matching was applied on the first restrike to predict the mobilized static bearing capacity (incl. the set-up).

 
Among the many project challenges two must be mentioned:

First of all there was the design and construction of an assembly to perform static load tests under water. In a joint effort between the construction contractor Bilfinger Marine & Offshore, engineering firm Fichtner Wind & Water, the Norwegian Geotechnical Institute NGI and Allnamics a practical, innovative and re-useable assembly was developed that can be installed from the vessel deck without diver intervention.

 

Secondly the underwater sensors had to remain functional for at least 3 month in salt water at a water depth of 40 meters (so they could be used during the second phase). The sensors supplied by Allnamics all met this challenge. Apart from supplying the sensors Allnamics was also contracted by Bilfinger to perform and evaluate the static and dynamic load tests of the test piles. These tests were performed using the PDR, a state-of-the-art multi-purpose monitoring system that can also be used for Rapid Load Testing.

 

For more details about this project click here to see a movie made by SAL Offshore, and in case you would like more information on the PDR or underwater testing, please feel free to contact us or download the PDR brochure.

Underwater Sensors (UW)

Under water Sensors (UW)

 

Pile Driving Frame

Pile Driving Frame

4 Paal tijdens het hijsen dichtbij

Pile with sensors during lifting

5 Paal tijdens het hijsen

Pile during lifting

6 Aansluiten sensoren op de PDR

Connected double sensor set on both PDRs

7 Menck Hamer

Menck Hamer

8 Meten tijdens het heien

PDA Measuring during driving

10 Ophalen kabels na 10 weken op de zeebodem

Retrieving cables after 10 weeks at a water depth of 40 meters

 

11 Aansluiten kabels aan de meetapparatuur

Connecting the cables on the PDR monitoring unit

12 Statische proefbelasting

Measuring during SLT

13 Eenvoudige voorstelling van meetsetup

Simple explanation of the measurement setup

14 Meetframe SLT

Static Load Testing Frame

15 Reactieframe in Water

Reaction frame

16 Onderwater robot

ROV

17 Onderwater sensoren

The UW sensors

PDA on test piles for foundations of wind turbines

 

In October 2014 Allnamics performed PDA on test piles for the foundations of two wind turbines near Urk in The Netherlands.

 

The foundation for these wind turbines, which have a tower height of more than 100 meters (330 ft) and a capacity of 7 MW, each consist of 60 prefabricated square concrete piles (500 x 500 mm2, 20 x 20 in2) with a length between 19 and 23 meters (63 and 77 ft)

 

The PDA was performed with Allnamics’ wireless PDR, which allowed for registration and recording of all relevant hammer blow data, such as the transferred energy, the stresses in the pile and the dynamic pile resistance.

The end-of-drive data for each test pile were analyzed using Allnamics-DL signal matching software to determine the lower limit of the static pile resistance.

 

Shortly thereafter these piles were subjected to a Rapid Load Test using Allnamics’ StatRapid.

 

PDR and the combined sensors mounted on the pile

PDR and the combined sensors mounted on the pile

PDR aan Prefab Paal Urk Tijdens Hijsen

PDR on the pile during lifting of the pile. (No measuring cable)

PDR aan Prefab Paal Urk Tijdens Heien.

PDR on the prefab pile during driving and sending wireless the data.