TEXTILES.ORG
The award is part of the 2007 International Achievement Awards presented by the Industrial Fabrics Association International (IFAI).
Project description
This project underscored the advantages of using geogrids to build many of the biggest retaining walls ever constructed in Chilpancingo, the capital city of the state of Guerrero, México.
Retaining walls were designed to support both static and dynamic loads. The length of all the retaining walls is more than 300m and they were built from 7-12m high. This project needed the use of a special polyester geogrid as a soil reinforcement system. A PET geogrid (60 kN/m resistance) and a geogrid (100 kN/m resistance) were used in the project. The geogrids were placed in layers, filled with compacted soil along the entire anchorage longitude, according to the design; and the use of concrete block provided an aesthetic finishing (wall face). Later, the concrete foundation block was set into the system through tablets and staples providing the correct alignment for all pieces.
The client for this project was an enterprise that depends directly on the federal government of Mexico. This company gives housing support to its own employees. This client previously contracted with some construction companies to build the houses, and it also has its own construction department to supervise the final jobs. So, in the end, the company can get an excellent product, and it can give its employees a place to live.
Recently, the company bought land to build the latest houses. However, this land had a very irregular topography, being at the top of a hill, which caused huge leveling differences. The substantial differences of levels required the construction of platforms to support the houses, and these platforms required many retaining walls to support them, in order to increase the residential area, with a very good stability for roads and houses.
Difficult topography
The complexity of the topography hindered usual building methods. First, the construction company had to solve problems with subgrade soil. Many cubic meters of soil were moved from the multitude of ground cuts on the hill to reach the settlement levels for all the platforms. This same material was used, and its functionality tested, working with the geogrids so that the mechanical properties could be checked, and to be able to make another design using geogrids.
The client also wanted to build the largest possible number of houses for its employees, and that is why a great number of vertical walls were erected, to take advantage of the whole area. The design of the retaining walls required a great effort due to the different heights and lengths for each section of the departmental division, with verticality the critical factor for the walls.
The planning and construction had to adapt every wall according to the surface geometry and also had to consider its corners and even some curves from the wall. Another important aspect regarding this project was that it had to be built efficiently and on deadline, with an effective system, and in a cost-effective manner.
Results
The results were even better than expected—every containing wall was completed without problems or delays. Geogrid construction processes resulted in a very fast construction style and were even less costly than the usual methods with concrete and steel. The concrete block finishing gives the retaining walls an aesthetically pleasing look and a comfortable feeling for the residents.
Geogrids are a relatively new reinforcement system in Mexico. This project was very interesting for many contractors near the zone and for many governmental agencies that support housing and are responsible for constructing similar containing walls. In Mexico, it is not a common thing to observe retaining walls of such height, because they are difficult to build using the traditional methods. However, today they are possible thanks to geogrids.