Conduct ‘Quality Assurance, Control’ on NH-275 pronto

File photo of Mysuru-Kodagu MP Yaduveer inspecting the retaining wall on NH-275.

By V.N. Prasad

Following are my observations with reference to the news item titled ‘Bent sections of retaining wall rectified on NH-275 in Mandya’ published in Star of Mysore dated Oct. 20.

Right from ‘Day One’ while driving along the Service Roads, I observed the phenomenon called bulging of sidewalls; termed “Reinforced Earth Walls” (abbreviated as RE Walls) in Highway Engineering terms.

Such RE walls are constructed on either sides to hold the road in between, against lateral collapse. RE walls facilitate economical ascent and descent of a highway to provide for an underpass. Needless to add that such RE walls on either side need sustained stability and absolute geometrics.

I am aghast at the term ‘maintenance’ of the RE walls, so early in the life of NH-275. I give reasons in the following bullet points for easy understanding of readers; to substantiate my views.

1. RE walls comprise prefabricated concrete slabs that can be of any shape like square, rectangle etc. They ought to be assembled on either side qualitatively in geometrics and sustainability.

2. The challenge is to assemble individual slabs in a line and in an absolute vertical plane, to serve as retaining walls. While it is cheaper than conventional retaining walls, it requires expertise and strict supervision; as the works are an integral part of earthworks.

3. The precast slabs on either side are strapped or tied with steel or polymer ropes and tensioned till line and verticality of RE slabs are perfectly in alignment in horizontal and vertical planes and locked for stability. Suitable ‘eyes’ are provided in the slabs to pass the tensioners; across the width. Therefore, the lines and verticality of every RE slab is directly related to how accurately they are strapped from end to end. They are not slabs in isolation.

4. From the first layer of earthworks, assembly of RE wall slabs, strapping, tensioning and locking are all stagewise operations that need precision, under strict supervision and documentation.

5. It needs time and expertise to align the slabs, tension strands, ensure accuracy, lock and permit further layers of earthworks. Such aligned and locked RE slabs shall not undergo distortion while further works are in progress. This is intricate and that was apparently lacking here.

6. Unless procedures are adopted to ensure error-free construction, such situations will crop up or bound to crop, as is the case now.

7. It looks laughable that a bunch of engineers gather around politicians to say that maintenance works are stringent. No Sir. This is a construction fault. ‘band aid ‘ will not help.

8. Driving rods and locking from the wall side will not help. And, God save your engineering knowledge of highways.

Defects on the highway are not only the bulging of RE walls but also the riding/driving surface of the NH. Several stretches are patched very roughly. Thuds appear all of a sudden. Undulations are umpteen, backfill of a few structures are insufficient in compaction etc.

I have already said this before and don’t mind repeating a million times. AASHTO (American Association of State Highway and Transportation Officials), was constituted in the US to plan, engage in designs, enlist competent contracting agencies, invite tenders, award contracts, engage Project Management Consultants (PMCs), document the entire contract procedurally and hand over the highway to the government”. PMCs assume and own projects with full responsibilities.