This summer, a group of 5 Imperial students travelled to Malawi to complete the construction of a 37 m suspended footbridge. Malawi is a small, densely populated country in southern Africa, ranked as the poorest in the world. It is also one of the least developed and least urbanised countries, where most of the population are semi-subsistence farmers. Malawi is famed for its friendly, welcoming people, and we were lucky enough to experience this first-hand.
This was the second phase of a two-year project. Work began in 2006 when a team of undergraduates, led by Andras Szollar, put together a design for the bridge. 5 students then went out to Malawi to begin construction, and despite logistical problems, completed the masonry and brickwork towers and concrete anchor blocks. This year, none of the original engineers were able to return, so Jumana Al-Zubaidi, Li-Teck Lau and I joined the team, along with expedition leaders Naomi Bessey (Physics graduate) and Daniel Carrivick (Geology PhD).
On our arrival in Lilongwe, the Malawian capital, we were faced with a long drive to the remote village of Uledi, in the north of the country. Uledi is a day?s drive from the nearest town, down dirt roads with enormous potholes, and it has no electricity or running water. The village is on the western bank of the North Rukuru River, which during the dry season is knee-deep; in the rainy season, it sometimes reaches a depth of 6 metres and regularly sweeps away people who try to cross. The eastern bank forms the border of the Nyika National Park. During the rains, park rangers were unable to get into the park to prevent poaching and those living on the eastern bank could not get to school, the market or the clinic.
While in the village, we slept in brick huts with a concrete floor, which we shared with various rodents and insects. There is no running water, so we washed in the river. This was fine for the guys, but Malawian women generally don?t show their arms above the elbow or their legs above the knee, so the girls had to wash fully dressed. All of our cooking was done over a campfire - we even managed to make chips!
We employed 30 local men to work on the bridge construction. They are basically unskilled, although some had worked for the team last year and knew how to make concrete and mortar. The men were paid 200 Kwacha per day, which is around 90p - apparently a good wage in Malawi! The working day began at 7.30 am when the men were divided into working teams and allocated their tasks for the morning. We broke for lunch between 11.30 am and 1.00 pm, when the sun was hottest, and then worked until 4 pm so that the workers could get home before dark.
One of the most exciting tasks was installing the cables. The bridge uses an 11 mm handrail cable and a 26 mm walkway cable, each of which is 130 m long. Both came on large reels, which we transported to the village on our three-tonne truck. The track down to the river was far too narrow and steep for the truck, so the cable had to be carried down on the men?s shoulders, spaced out along the length at roughly 6 m intervals. Placing the cables across the towers and attaching them to the concrete anchor blocks took a full day.
The cables then had to be tensioned, using pulley systems and a team of 6 men. We overpulled the cables to a higher tension, to allow them to sag under their own weight for 24 hours. Then we relaxed them to the final level.
With the cables in place, the wooden decking could be installed. This was designed in 2 m long units, which can be easily replaced if they rot or get damaged. Each unit is made from 5 longitudinal members, with 3 crosspieces. The crosspieces have notches which fit over the walkway cable. We used climbing harnesses to clip ourselves onto the cables, and then carried the decking units out to slot them on. This was really hard work, because each unit weighs around 35 kg.
The biggest job was building the earth embankments between the towers and the anchors. In total we used about 60 m3 of earth, which is a lot to collect and stockpile entirely by hand. On most working days, the majority of the workers were busy digging out earth on both sides of the river, and transporting it to the bridge. To support the sides of the embankments, we made a retaining wall by filling old sugar sacks with earth.
In order to protect the cables where they are buried inside the earth, we encased them in concrete. As anyone who?s been on the El Salvador project knows, mixing concrete by hand is really hard work. Not only did the workers do the mixing, but they also spent days collecting sand and gravel from the river to use as aggregate.
After 3 weeks? hard work, the bridge was finished. One final morning was spent on last-minute tasks, such as fixing ladders in place to climb up the towers and laying stone paths up to the bridge. Then all the workers arrived for the opening ceremony, along with the five village chiefs and several representatives of the national park. After a few speeches the villagers had the chance to walk across the bridge for the first time. We all went back to the camp for a traditional Malawian meal cooked by the local women, followed by celebrations that went on well into the night. The local maize beer, served warm and drunk with straws out of a communal bucket, turned out to be pretty potent, as one expedition member discovered!
One of the most interesting aspects of the expedition was working closely with the villagers. Although English is one of Malawi?s official languages, most people in rural areas only know a few words. Our driver, Wellington and Lachsun, the chief scout, acted as translators. But we also managed to learn some words of Tambuka, the local language and the villagers were really pleased that we were making an effort. Family life is really important in Malawi and we had lots of fathers and sons, uncles and nephews, and even some twins working together on site. The men were always keen to talk about their families (one guy, Manuel, has 11 children!) and wanted to know all about our lives in Britain.
Although much of our time was spent supervising tasks and making sure that the work was of a high enough quality to be safe, we also tried to get hands on with the work as much as possible. The workers thought it was hilarious watching us struggling with a job that they found easy; and they were very surprised to see girls doing carpentry! Making an effort to do some physical work made it easier to get along with the villagers. It?s also really important that the villagers were able to learn some construction techniques, such as concreting and carpentry. We hope that the community will be able to use these skills and the tools we left behind, to improve other facilities in the village.
So now the bridge is complete and members of the village and the national park have set up a committee to deal with maintenance. We left behind a manual giving information on basic repairs, and detailing potential problems to look out for. A biological expedition goes out to the national park every year, so they will be able to monitor the bridge and hopefully in a few years? time, one or two of us will go back to Uledi.