Rehabilitation of Road in busy city town centre in Karnataka
|Completion Date||May 2012|
Monsoons in North Karnataka are notorious for damage to roads. An example of this can be seen on the two-way paved road in the town centre of Hangal in Karnataka. This stretch was plagued with problems like reflective cracks, potholes, undulating surfaces etc., resulting in slow traffic movement and heavy vehicular damage.
Problem and Objective
This stretch had to be rehabilitated time and again over the past several years, and no solution was proving to be long-term. Since the area is a major commercial hub, it was not possible to completely close off this section for an extended period, and hence the need for a quick but long-term solution.
Conventional methods of road-making were previously tried, which proved ineffective. An engineered solutions using StrataWeb® geocells to strengthen the base course of the road was recommended and finally accepted by all local authorities.
StrataWeb® is essentially a HDPE cellular confinement system, which is light and can be easily transported even to remote areas in collapsed form. StrataWeb® sections are inert against chemical and bio-chemical environment generally found in soils. The cells of the StrataWeb® System provide a permanent flexible form, adjusting to the shape and grade of the soil. When filled with cohesionless material, StrataWeb® forms rigid mats capable of distributing imposed loads.
Initially, the surface was dressed and compacted. StrataWeb® sections were spread over the dressed surface manually and were connected using pneumatic staplers. The sections were secured into position with temporary metal anchors and then in-filled with granular material using a front loader, filling over by an extra 50mm. Post the filling, the layer was vibro-compacted and leveled.
Benefits to the Client
The StrataWeb® solution by Strata resolved the perennial issue of potholed roads and undulated surfaces. The authorities decided to assess the performance of the system in regular traffic and consequently delayed the asphalting of the road by 4-5 months to allow for one monsoon season to pass. . After the monsoon season, no undulation or settlements were observed on this unpaved section. The surface was then asphalted and the work was deemed completed. Implementation of the solution hardly affected traffic movement, thanks to speedy installation. Additional benefits to the client include cost savings by prolonging the cost of asphalting and managing their budgetary constraints in an efficient manner.
The Mechanics of StrataWeb®
Cross Section of StrataWeb® geocell
StrataWeb® geocells filled with cohesionless material form rigid mats capable of distributing imposed loads over a larger area.
When a vertical pressure is exerted on the non-cohesion fill within the StrataWeb®, lateral stresses are generated. Since all the StrataWeb® cells are filled with non-cohesive material, deflection of the StrataWeb® walls are negligible. Hence the lateral stresses thus generated equal to about (k₀ * q₀) in all cells, where k₀ is the “at rest” earth pressure coefficient for the in-filled non-cohesive soil. This increases shear strength of the confined soil within the geocells, and lateral stresses are generated in congruent cells as reaction.
This effect creates a stiff mattress which contributes to distributing the load over a larger area. Hence the pressure below the StrataWeb® system, p is lower than what they would be through a conventional load transfer system. Hence heavy loads are spread and can be safely transmitted onto weak foundation soils without distress.
Strata Geosystems (India) Pvt. Ltd., established in 2004, is a joint venture with Strata Systems Inc., USA (part of the 130 year old Glen Raven Group of Companies). Strata Geosystems provides end-to-end technical solutions, from design to execution for geotechnical applications such as reinforced soil walls (flyovers, road over bridges etc.), soil embankment stabilization, reinforced steep slopes, reinforced foundations, slope protection, load support for paved and unpaved roads and bearing capacity improvement, landfills and reservoirs. Strata is reputed for its quality, durability and cost effectiveness and manufacture conforming to strict international quality standards. Its committed team of experienced design and project engineers ensures timely and accurate installation.
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