ToNA, RoadWay ConsTruction
Written on Monday, November 30, 2009 by Jose Sanchez Marquez
This was my second opportunity working in the construction of highways, although I only participated in the project for several months and the main idea of this project was, build a safety and well done roadway to this village, that for several years was expecting this intervention.
| PROJECT NAME: | Technical Supervision, Administrative, Financial, Social and Environmental for improvement and paving of Tona’s road, K5+00 to K18 +870, Santander – Colombia. |
| Supervisor: | JOYCO LTDA. |
| Constructor: | Consorico SE-1 |
| Contract Value: | $10.060.315.965 millions of Colombian pesos |
PROJECT DESCRIPTION:
This Project was awarded by the government of Santander to JOYCO LTDA, Joaquin Ortiz and Company. A company that specialized in the consulting and engineering design, and I worked there as a Civil Engineer.
The project was divided in two stages, STUDIES AND DESIGN and CONSTRUCTION SUPERVISION.
The first stage began in July 9 and finished in September 9, in where previous studies were reviewed and updated and in some occasions they were made it again, like the traffic study which determined that the total number of axles equivalent for the next 20 years would be 400.000 vehicles. Afterward the pavement design showed that was necessary the use of two structures in different parts of the road, asphalt and concrete pavement.
However it was also necessary to perform the CBR test (California Bearing Ratio) a penetration test for evaluation of the mechanical strength of road sub grades and base courses. Finally we made a material characterization to identify the sub base material. On the other hand, we also design culverts and concrete retaining walls with the different heights (2 – 6m).The first stage began in July 9 and finished in September 9, in where previous studies were reviewed and updated and in some occasions they were made it again, like the traffic study which determined that the total number of axles equivalent for the next 20 years would be 400.000 vehicles. Afterward the pavement design showed that was necessary the use of two structures in different parts of the road, asphalt and concrete pavement.
PROJECT LOCATION
Tona village is located about 36 Km from Bucaramanga, more or less 45 minutes by car.
The video shows how the state of the roadway was before the improvement started, it only shows the first 3 kilometers from K5+000 to K8+000 of the 14 kilometers than the contract established. In the video we can also appreciated the width of the road, how small it was, and how the slopes were formed by rocks in several parts of the road.
However the road didn’t present big problems related to subsidence or landslides, thanks to this the road remained acceptable safety conditions for vehicles. On the other hand the bridges in the 14 kilometers, the majority of them with more than 20 years of existence without any kind of maintenance, reason why was necessary analyze if they were capable of resist the weight of trucks and heavy vehicles.
Also in some cases was necessary increase the width of the bridges due to only one car was able to pass over it and the main idea of the project was try to generate a comfortable and safety road.
One of the positive things that we found was the mechanical strength of the soil, after CBR tests and identified the material particles size was determined that sand was the principal material with a CBR result of 20%, and excellent soil with the possibility to withstand high loads. Reason why the pavement design didn’t have high thickness, a 15 cm of thickness for the granular sub base, 15 cm granular base and 6 cm of pavement, MDC - 2.
However the topography of the zone is abrupt, there are big and dangerous slopes along the way. Reason why more that 30.000 m3 must to be remove and transport to another place.
CONCRET WALLS CONSTRCUTION
The construction of these walls took an important role during the project, due to it were necessary before to put the pavement. But also was necessary the construction of box culvert, gutters and filters very important to drain the water of the road. The walls were design by the Eng. Rafael Zafra according to the topography of the zone.
In the picture bellow you can detail the two wall options that we had according the necessity of the road.
In the picture bellow you can detail the two wall options that we had according the necessity of the road.
The first step was the wall location through coordinates and levels. Them the excavation started. In the majority of the cases the excavation was made by heavy machine to increase the work performance.
In some cases was necessary realized improvement on the soil, putting steel anchors of 5/8’’ where excavation was impossible by the rocks. In the picture bellow we can see how the steel anchors were put after put a lower concrete layer of 7 cm of thickness.
In some cases was necessary realized improvement on the soil, putting steel anchors of 5/8’’ where excavation was impossible by the rocks. In the picture bellow we can see how the steel anchors were put after put a lower concrete layer of 7 cm of thickness.
Once the improvement was done the process of install the steel anchors began. The constructor use wood frame to contain the concrete, however steel frame develop best finishes to the view. In the pictures bellow we can see how the steel was put according the wall design. Also the concrete resistance used was 21 Mpa, and CEMEX was the company who sent the concrete until there.
This was the final result of the wall. We can see also the filter that surrounds the wall. Done the wall the road finally get width of 7.0 m, necessary space for the pass of two small vehicles at the same time.
CUTS AND GRADINGS WORKS IN SLOPES
In zones where the slopes were formed essentially by rocks, the design established that the cut angle must to be almost vertical to try to ensure 6 m of width to the road and pave the mayor number of kilometers.
To do the job we count with two DOOSAN 225 crawler excavators, everyone with a loader of 1 m3 of capacity. This kind of machine made possible to achieve an impressive breakthrough in a few days.
Doosan Home Page
For every explosion was necessary made rock perforations between 0.80 and 1.0 m deep in the rock. Them the R-1 explosive was installed and was detonated by remote control.
In the next video we can see some explosions, all the personal were located to a distance of 200 m. and when the explosions finished, the expert went to the zone to supervise that everything was under control.
This was the final result of the slopes cut in one part of the road; we can see that the width allows the pass of two vehicles at the same time. Once they were made the topography team went to the field to rectify if the cut was correct or not according to the geometrical design of the road.
This video shows the variety of animals that appeared during the construction. Spiders and snakes were the most common animals to found on the mountains.
ROAD FORMATION
One of the most important Works during the construction of the pavement was the construction of the filters. They help to drain subterraneous water to the culverts of the road. Every filter had a length and width of 80x60 cm and they were located on the right side of the road, or where the mountain slope was located. In the picture we can see that the construction of one of them.
Every excavation and material placement was made with the help of the backhoe to improve the work performance.
Every excavation and material placement was made with the help of the backhoe to improve the work performance.
In the next picture we can see also how difficult was the construction of the filters, rain was one the biggest problems, making the road impassible for vehicles. After the filters construction the motor grade starts the formation of the soil, leveling the soil or just cutting.
The picture bellow show a part of the road, where the filter (left) was finished and the motor grade did the soil formation. Them the vibratory roller compact the entire floor, increasing the safety of the road.
Now in the picture bellow we can see how the motor grade move the granular sub base according of design thickness, during all this time the topographer check if the machine needs to cut or move more material, until they reach an average thickness. Then the vibratory roller makes it part, compacting the entire zone.
Unfortunately I couldn’t finish the construction of the road, I wasn’t there when they started the pavement, due to I was called to work in HOLCIM COLOMBIA S.A as a WORK Inspector. However I must said that the experience was great and I learnt a lot from Eng. Jairo Gamboa and Eng. Guillermo Valencia excellent bosses and also I left excellent partners.
Work Team
Thanks for the opportunity
Posted in
construcción de vias,
grader,
heavy machines,
highways,
JOYCO LTDA.,
milling machine,
plastiment tm5,
TONA
Jose me hace muy feliz ver todo lo que has aprendido y vivido en tan poquito!!! y lo que te falta hacer!!!!!! Felicitaciones!
Gracias amor, por tu apoyo y buenos deseos