Opinion

Speedy post-earthquake reconstruction: Through the use of bamboo-reinforced soil

One of the notable construction techniques is the use of bamboo-reinforced soil for constructing the walls. It used straw fibers, mud and bamboo. Such houses can even now be found in the distant villages in Madhes

By Jiba Raj Pokharel

File - Workers engaged at their work on top of Dharahara tower, at Sundhara, Kathmandu, April 21, 2021. Photo: RSS

A fleeting glance of the history of Nepal reveals that the country has been a victim to an earthquake of high magnitude nearly every 100 years and a moderate one approximately every 50 years. Correspondingly, we had mega earthquakes in 1834 during the time of Prime Minister Bhim Shen Thapa and yet another in 1934 when Juddha Shamsher was the Prime Minister. In 1988, eastern Nepal experienced yet another earthquake after 54 years.

Though earthquakes have been occurring in Nepal since time immemorial, some even reckon that Nepal's origin is in earthquakes given the presence of the Tethy sea in ancient times, which drained after the tectonic movement raised its altitude to the present state. We do not have records of the earlier earthquakes but after its documentation from the earthquake of 1223, Nepal has experienced mega, moderate as well as minor earthquakes every now and then. The most recent earthquake that struck Nepal was the Jajarkot earthquake measuring 6.5 in magnitude, which left 158 people dead and several wounded.

Disasters, including earthquakes, can be harmless if we have adequate preparedness. We can see this in Japan, where earthquakes, mega or moderate, come and go without any damage unless followed by a damaging Tsunami. But Nepal lacks preparedness, and it is like a student who fails due to no preparedness prior to an examination. In the following earthquake, the newly constructed house again tumbles due to the absence of earthquake-resistant technology and causes lots of sufferings again.

The nation also does not take it very seriously. When there was an earthquake in the year 2008 in China measuring 7.8 in magnitude, which killed 69,000 people, its Premier Wen Jiabao reached the affected site within 90 minutes and remained there for weeks supervising relief, rescue and later reconstruction. Consequently, 99 per cent of the 41,130 projects were said to have been completed after merely two years. After a week, neighbouring Burma was struck by the Nargis cyclone, but the relief and rescue efforts there did not even mirror in miniature the Chinese counterpart.

Our President and the Prime Minister went to Jajarkot just for an eye wash kind of visit. In fact, more than facilitating the rescue and relief operation, their visit hindered it because the rescue actors had to be present to welcome them. Neither the relief nor the reconstruction works carried out in the early earthquakes have been satisfactory, of which the 2015 earthquake reconstruction is a glaring example.

The government has been parroting time and again that it plans to complete the reconstruction work as soon as possible. First, it was said that it would be finished before the monsoon. But the monsoon has already started pouring in with no sign of the reconstruction work making any headway.

There are several factors responsible for a tortoise-like pace of reconstruction works in our country. But one of them is certainly the abandonment of local materials and techniques followed by over dependence on foreign materials and aid. In the 1934 earthquake, Juddha Shamsher had rejected foreign aid. Foreign materials like cement and steel have become a kind of eyesore given their ironic contribution to climate change. Our ancestors used low or no energy-consuming materials like stones, bamboo and mud.

One of the notable construction techniques is the use of bamboo-reinforced soil for constructing the walls. It used straw fibers, mud and bamboo. Such houses can even now be found in the distant villages in Madhes. One of these houses was surveyed in Saptari district by this columnist for his doctoral dissertation.

In fact, some stray studies had been made in the past about the bamboo reinforced soil. One article published in Leonardo Journal of Sciences, a Massachusetts Institute of Technology publication, authored by Mustafa Mohammad in 2008, showed that the unconfined compressive strength of the laterite soil alone, soil with one bamboo specimen (2.5%), two and three were 221, 300, 400 and 661 Kilonewton per square meter. Similar soil when tested in Nepal gave approximately similar results of 206, 284 and 529.

An unconfined compressive test of bamboo reinforced soil with 18 per cent bamboo revealed the strength varying from 2500 to 3200 Kilonewton per square meter. It competed with the compressive strength of the brickwork constructed in cement mortar of 1:4 proportion, which is generally taken as 2500.

Our ancestors may not have crushed the bamboo reinforced soil cube or panel in a Universal Testing Machine as has recently been done by this columnist. But they were well aware of its strength and used it for the construction of the wall. They used a robust material which does not have detrimental impact on the environment. Now we have overused modern materials, and one can see how the construction sector is one of the biggest carbon emitters along with the transport sector. Similarly, the floor can be constructed by using the grid bamboo beams. Such a house will also be earthquake-resistant as bamboo is very resilient to earthquake forces.

People are rightly susceptible to the durability of bamboo. But when it is concealed it goes for a long time. One can see how houses using bamboo plastered with mud on both the sides have endured for generations in the tarai. Moreover, there are indigenous treating techniques like dipping in a pool of water before their use.

We have to build back better after the disasters. The use of reinforced bamboo soil helps us to do it as its strength is at par with brick and cement masonry. Moreover, it does not have any carbon foot print. Besides it is cheap, and it provides employment to the local people. The government should seriously think about its use in the reconstruction work in Jajarkot and Rukum. The failure to do so will land the country in similar situation as in the past.