Construction of Retaining walls in three steps at different levels to support Villas in Sobha Bela Encosta Project in Kozhikode, Kerala.

P R O J E C T  D E T A I L S

System Owner Contractor Construction Year Designer + Consultant
TerraLink™ and
Reinforced Earth®
Sobha Developers Limited Sobha Limited 08/2014 to 06/2017 • Terre Armée (Reinforced
Earth India Pvt. Ltd.)
• Geocon Consultants

Background

Reinforced Earth India has been involved with the client (Sobha Ltd) in land development for a real estate project titled “Sobha Bela Encosta”. This project consists of high end Portuguese styled architectural cottages using the construction of GeoMega® wall in the filled-up area and a TerraLink™ wall in the excavated portion of the property.

This project is being constructed in a hilly terrain. A balance between the ‘cut’ and ‘fill’ had to be maintained to construct the cottage houses at different elevations. During the concept stage Reinforced Earth India proposed as an alternative solution, to construct some cottages over the GeoMega® walls and others on top of the TerraLink™ structure. This idea was accepted by Sobha Ltd. and the contract was awarded to RECo India.

The stages of construction included stabilization of excavated hill slope by installing TerraNail® encased with grout, in order to create an in situ coherent gravity structure with TerraQuad facing for both Reinforced Earth® and TerraLink™ techniques.

Challenge

In the project site, the difference in elevation from first row of villas to club house was 30m. Construction of conventional Retaining Wall would not have been suitable, technically and economically, with the dead and live loads of the villas on the Retaining Walls along with soil pressure of 10m height. The ground profile was also not suitable for construction of conventional Retaining Wall or any other type of retaining structure.

The original ground profile and proposed construction profiles were such that, a uniform solution would not have been possible to fulfill the requirement. Additionally, the foundation details of the villas were to be accommodated during construction and their construction loads were to be accounted for.

Considering the high rainfall in the area and the presence of the water stream at the foot of the hill, seepage of water posed a major threat in constructing any type of retaining wall.

Solution

After complete site survey, Terre Armée India proposed a unique solution of TerraLink™ system along with Reinforced Earth® Wall to create an integrated innovative engineering solution to help client realise their project without any technical compromises and with economic advantage.

TerraLink™ Wall was proposed at top two layers of villas where the original ground profile of the hillock was too close and sufficient space was not available for laying of soil reinforcement for a conventional Reinforced Earth® Wall. In TerraLink™, grouted TerraNail® are drilled into the existing slope and then a layer of prefabricated galvanized steel mesh is connected using bearing plate avoiding local failures of the slope. The mesh is mechanically connected to Reinforced Earth® Wall with GeoStrap® as soil reinforcement at a distance varying from 0.5m to 1.0m.

For bottom pier of villas, retaining wall with Reinforced Earth® system with GeoStrap® as soil reinforcement was proposed as enough space was available to lay soil reinforcement as per design requirement. The height of wall varied from 5m to 13m.
Both TerraLink™ wall and Reinforced Earth® wall were designed for 60 KPa loading and designed as per BS 8006:1995, IS 1893:2002 & AFNOR NF P 94-220.

Terre Armée India was responsible for design, sourcing of specialized materials and on-site installation of system along with technical assistance at site. The project was completed successfully within 10 months time.

 

 

Construction of Vehicular Underpass (VUP), Bastora Junction, NH 17, Goa, India.

P R O J E C T  D E T A I L S

Structure Type Owner Contractor Construction Year Designer + Consultant
TechAbutment®,
Reinforced Earth® Wall
Public Works Department (PWD), Goa Assmas Construction Pvt. Ltd. 01/2017 to 04/2018 • Terre Armée (Reinforced Earth India Pvt. Ltd.)
• RITES Ltd.

Background

Goa is a popular tourist destination in India, experiencing ever increasing traffic volume. The National Highway 17 (NH 17) provides major connectivity to Goa with neighbouring states. Goa has approximately 101 km of NH 17, running parallel to its coastline. Bastora junction is one of the major focal points, which experiences huge traffic congestion due to North-South connectivity. Due to the huge traffic demand, Public Works Department (PWD) Goa is constructing a bi-directional Vehicular Underpass (VUP) at Bastora junction to ease the traffic. A VUP of  20 x 5.5m clear span is proposed with  23m carriage way width.

Challenge

Considering the project location and increase in the traffic density, completion time-line was the essence for this project. Safety of commuters during construction period was a major concern and challenge, as the terrain of Goa offers very limited space to provide traffic bypass or any type of diversion. The ground investigation revealed that the foundation soil strata was very poor up to 13m depth. Construction of wall and the true abutment on such poor strata was also another challenge and differential settlement was expected. Differential settlement on the abutment shall result in cracks on the bridge girder and slab.

Solution

After understanding the needs of the client and the project, Terre Armée India proposed a unique solution of TechAbutment® system along with Reinforced Earth® Wall solution to create an integrated innovative engineering solution to help client realise their project without any technical compromises,  with economic gain and time advantage.

Since, the geotechnical property of the foundation soil was not good, Terre Armée India proposed ground improvement and it was accepted by the client and the contractor.

TechAbutment® system is a true abutment where RCC Griders or Deck slabs are directly rested on Reinforced Earth® Walls. The uniqueness of this solution is that the conventional RCC abutments can be completely replaced with discrete panels, which provides better aesthetics also. TechAbutment® system was proposed at closing wall and return wall up to the length where the wall is subject to the bridge load. Considering the high loads, inextensible soil reinforcements were adopted. Terre Armée India adopted High Adherence Galvanized Steel Strips® to construct safe and sustainable true abutment solution.

For the approach ramp, Terre Armée India proposed to adopt GeoMega® system where GeoStrap5 soil reinforcing strips were used. Terre Armée India was responsible for design, sourcing of specialized materials and technical assistance at site for pre-casting and installation activities. The project was completed successfully within a span of 13 months.

 

 

Coastal road project from NH- 4B near Navghar to Sector- 63 at Dronagiri, Navi Mumbai with TechSpan® for Bridge Structures – 3, 3A & 4.

P R O J E C T  D E T A I L S

TECHSPAN® STR SPAN Owner Contractor Construction Year Designer + Consultant
340 m City and Industrial
Development Corp.
(CIDCO)
J. Kumar Infra
Projects Ltd.
2017-18 Terre Armée (Reinforced Earth India Pvt. Ltd.)

Background

City and Industrial Development Corp. (CIDCO) of Maharashtra (CIDCO) is building a 34 m wide road from Nh-4B near Navghar to Bokadvira adjoining NMSEZ at Dronagiri, Navi Mumbai. CIDCO develops all the new suburbs around Mumbai and is an undertaking of Govt.of Maharashtra. The project has been contracted to J. Kumar Infra Projects Ltd.Mumbai.

The road is of prime importance since it forms a parallel link from NH-4B to JNPT in its final stretch and would cater to heavy traffic projected in the coming years.

Challenge

In the stretch of 4.8 km there are three  holding ponds along the proposed coastal road alignment where CIDCO needed to  provide bridge so that the water movement to holding ponds during tidal variation is not affected. CIDCO was also looking for cost effective and aesthetically good structures for these bridges.

The foundation at these three locations has brown marine clay with high plasticity.  The thickness of the strata ranges from
4.0 m to 14.0 m.

Solution

REIPL came up with the solution of TechSpan® structures for the ponds no 3A, 3 & 4:
• For Bridge no 1 (Holding pond no 3A) & Bridge no 2 (Holding pond no 3): REIPL proposed two pin TechSpan® structure with 3 arch spans with Reinforced Earth Head walls.
• For Bridge no 3 (Holding pond no 4): REIPL proposed two pin TechSpan® structure with 4 arch spans with Reinforced Earth
Head walls.

Based on the hydraulic cross section requirements and proposed coastal road formation levels, the Span of the 2 Pin TechSpan® arch structure is 9m and Rise is 4.5m.

In view of the marine clay and tidal effects the TechSpan® structures are being built on pile foundations. 

Total length of each TechSpan® structure is 340 m and the carriageway width is 32.5m. The spandrel walls and wing walls are formed from reinforced soil retaining walls using EcoStrap®.

 

 

Construction of Yard at Kalamboli in Navi Mumbai in Maharashtra, India.

P R O J E C T  D E T A I L S

System Owner Contractor Construction Year Designer + Consultant
RE Wall Type: TerraTee®
with High Adherence
GeoStrap® and GeoMega®
Connectors
Central Railways GOI MVR Constructions 03/2017 to 11/2017 • Terre Armée (Reinforced
Earth India Pvt. Ltd.)
• IIT Mumbai/
Central Railways

Background

Kalamboli is a railway station on the Vasai Road – Diva – Panvel route of the Central Line, of the Mumbai Suburban Railway network. The yard is being developed at this station for the goods train carrying heavy loads.

The railway line was planned on embankment height varying from 3 mt to 6 mt in height and of 550 mt long. The central railways had approached Terre Armée India to provide an innovative and sustainable solution to build the embankment to support railway loading.

Challenge

The most challenging part was to convince the railway authorities to use Geosynthetic soil reinforcement.

The central railways wanted to finish this project in a duration of 6 months, the total length of RE wall to be completed was 550m.

Central railways were concerned about the drainage system which would be adopted for construction of RE wall.

Economy was a major concern, the system had to be cost effective when compared to conventional retaining system.

The surcharge loading on the RE wall was approximately 48kN/m2.

Since this was the first time, central railways was using Reinforced Earth® wall techniques for supporting railway tracks there were many apprehension from the client on the use of this technique.

Solution

In a detailed design process, Terre Armée India used the in-house technical know-how to design the Reinforced Earth® wall using High Adherence GeoStrap® with synthetic GeoMega® connection system. HA GeoStrap® as soil reinforcement having lateral ribs and made of high tenacity polyester yarns (PET) placed in tension and co-extruded with linear low density polyethylene (LLDPE) to form straps of 50 mm wide. System consists of connection system made of molded polypropylene  sleeve, a totally metallic free connection system. Project made use well graded fill material having angle of internal friction (Ф) > 32o and considering a 32 MT Axle loading as design as per RDSO guidelines.

Failure surfaces through reinforced soil block & extending beyond it or encompassing the foundation soil has been analyzed to ensure sufficient length & strength within the reinforced soil mass. In this project client had insisted on performing the hand calculations and graphical analysis, hence the calculations were performed with Swedish Circle Method.

As an additional safety for such important structure it was suggested to use Geocomposite Drain/Geomenbrane below the ballast on railway track to avoid seepage of water from the tracks.

Surface water runoff drainage system have been adopted near the coping beam on the top with proper gradient to facilitate the additional water coming on the railway tracks.

The foundation here was moderately weathered basalt at a depth of 3m. So the minimum foundation depth considered was 1.7m.

 

 

Construction of TechBox™ for Railway Underpass at ACC cement plant at Jamul, Chhattisgarh in India.

P R O J E C T  D E T A I L S

System Owner Contractor Construction Year Designer + Consultant
TechBox ™ 6mx3m ACC Limited ACC Limited. September 2017 Terre Armée (Reinforced Earth India Pvt Ltd) + Aarvee Associates

Background

The railway tracks under South East Central Railway is the life line for the ACC cement plant located at Jamul in the state of Chhattisgarh, India for the logistics of supply of raw materials and to dispatch of cement/clinkers by wagons. Vehicular movement along the road was interrupted frequently due to the existing railway level crossing inside the plant. This access road along the outer periphery of ACC Jamul cement plant is one of the important connecting road for ACC staff colony and other adjoining residential areas.

To eliminate the obstruction of vehicular movement due to railway crossing, it was necessary to construct an underpass or a railway over bridge (ROB). However, due to shortage of available space, the ROB option was dropped.

ACC Ltd. then consulted Terre Armée In India regarding a viable solution for the above scenario. To ensure uninterrupted movement of the wagons during construction of Railway Underpass, Terre Armée in India proposed precast box structure TechBox™ system. ACC Ltd awarded this job to Terre Armée in India for construction of one Railway Underpass using TechBox® Technology.

Challenge

The approach Road towards ACC Colony is intersected by three Rail Tracks which is the lifeline for Plant Logistics for raw material and dispatch of cement. Frequent obstruction to vehicular movement along the above approach road due to movement of Railway Wagons was causing difficulty for the residents.

Construction of conventional underpass was also not feasible as it would have shut the wagons dispatch system during the long construction period. This would have affected the operation of the plant.

Terre Armée in India initiated the for construction of one Railway Underpass using TechBox® Technology. The key challenges were to minimize the shutdown period of Rail Tracks, which was is indispensable for the plant operations. The execution had to be done in two parts, keeping at least one track operational to support plant logistics.

Time allotted for two phases of installation and of Box Structure and restoration of railway movement on at least one rail track was only 17 days.

Solution

Terre Armée in India used the in-house technical know-how to custom-design the requisite cross-sections for this project. Based on the design, the moulds were customized to meet the design specifications.

The barrel length of the underpass is 26.5m and the internal dimension of the underpass is 6m wide x 3.5m high. There are 3 parallel railway tracks and Terre Armée in India proposed part construction, in which one track always remained live for handling of plant logistics. This is indispensable for the plant operations.

The pre-casting of box segments was completed in the designated casting yard close to the installation site and was installed at the desired location by cut ‘n’ cover method. Lifting System was adopted with a combination of Fabricated Spreader Beam and H T Freyssibars was extremely effective while handling pre-cast segments weighing 54.50 MT (including weight of lifting system). Installation of seven (7) units in the first phase was completed in 8 Hrs. Installation of ten (10) units in the second phase took 16 hrs even after hindrances due to constricted approach of crane.

The TechBox® technology has been proved to be far superior to the conventional in-situ Underpasses. It reduced the shutdown period of rail tracks to a great extent.

Design by:   Firefly Communications