StrataWeb® carries port traffic over clay subgrade on SH-84

StrataWeb® carries port traffic over clay subgrade on SH-84

Main Client PWD Maharashtra
Contractor (Strata’s immediate client) M/s B R Thakur Road Contractors
Solution Offered StrataWeb® geocells
Application Road subgrade strengthening with StrataWeb®
Project Duration Seven days in November 2012

Background

Jawaharlal Nehru Port (JNP) at Nhava Sheva, Navi Mumbai is spread over 10 square kilometres and is the largest container port in India. The PWD Maharashtra bears the responsibility of maintaining all the State Highways in and around the JNP area. State Highway SH-84 connects the JNP-Panvel Road junction to the ONGC terminal at Uran and experiences very heavy traffic movement. Due to heavy loads, the road stretch has always had issues of cracking and subsidence, requiring recurring and persistent annual rehabilitation.

Objective

Due to the heavy traffic movement on account of the ONGC Terminal, the road stretch was under distress time and again and its regular maintenance was proving to be an expensive exercise for PWD. Such maintenance would require frequent shutting down of sections of the road and traffic diversions, which further compounded the woes on this vital link to the terminal.

Considering all factors for long term subgrade improvement, longevity and economy, a StrataWeb® engineered solution was finalised. To prove the efficacy of StrataWeb®, the stretch closest to the terminal was taken up initially, about 450m (km 9.2 to km9.65) with road width of 5.5m.

Design Solution

Considering the weak subgrade and the heavy loading, a solution using StrataWeb® Style SW35, 150mm cell depth was worked out. High strength polymer cable ties were used for cell to cell and flap to flap connections between StrataWeb® panels. The StrataWeb® cells were filled with GSB (Granular Sub-base) Gr-III material.

Construction Overview

StrataWeb® panels of size 2.6m X 5.6m were used. The 2.6m side was placed along the width of the carriageway, while the 5.6m side was along the length of the stretch. GSB Gr-III was filled within the cells using highway dumpers. The geocells were filled to full depth of 150mm, plus an additional cushion of 50mm. The GSB was spread with a front-loader.

In this way, one lane of 2.6m width was opened to traffic speedily as a diversion, and the balance road-width was taken up and completed in a similar manner. The entire width of the stretch was completed in record time.

RESULTS

The rapid installation of StrataWeb® and re-opening of the road to heavy traffic within record time was much appreciated by the PWD, and more so by the ONGC Terminal. The entire stretch was satisfactorily completed in seven days with minimum labour and without disrupting the free flow of traffic. Other than diverting the traffic along the adjoining lane, no obstruction or diversion of the road was required, and no heavy machinery was needed. The conventional system of road rehabilitation could not have been done at a faster pace.