Imperial College Building Bridges 2007 Expedition Report
Total Page：16
File Type：pdf, Size：1020Kb
IMPERIAL COLLEGE BUILDING BRIDGES 2007 EXPEDITION REPORT An expedition to complete the construction of a footbridge across the North Rukuru River at Uledi, on the north western corner of the Nyika National Park, in Northern Malawi. Imperial College BUILDING BRIDGES 2007 Expedition Report Northern Malawi Thursday 28 th June - Wednesday 1 st August 2007 Aim To complete the construction of a suspended footbridge across the North Rukuru River near Uledi, and to protect the adjacent river bank. www.imperial.ac.uk/expeditions Editor DANIEL CARRIVICK 25 Hamilton Road, Tiddington, Stratford-Upon-Avon, Warwickshire, CV37 7DD. England [email protected] Published by: Imperial College London, South Kensington, London, SW7 2AZ. Mar 2008. All information published here is given in good faith and is correct and accurate to the best of our knowledge. We therefore accept no responsibility for any loss, injury or inconvenience sustained from anyone using this report. -0- IMPERIAL COLLEGE BUILDING BRIDGES 2007 EXPEDITION REPORT Contents Maps A & B – Malawi maps (fold out sheet) Summary 2 Introduction 3 Expedition members 4 Naomi Bessey 4 Daniel Carrivick 4 Harriet Kirk 5 Jumana Al-Zubaidi 6 Li-Teck Lau 6 Engineering Report 7 Summary 7 Background 7 Aim 7 Planning and Preparation 7 Method 8 Results & Future Work 17 Discussion 17 Bibliography 18 Administration & Logistics 20 Training 20 Permission & Permits 21 Fund Raising 21 Finances 22 Insurance 23 Travel 23 Food 24 Accommodation 26 Communications 27 Clothing & Equipment 28 Risks 29 Medical Issues 30 Environmental Impact 31 Photography 32 Diary 34 Leaving London 34 Shopping in Lilongwe 35 To Nyika National Park 36 Arrival in Uledi 37 Handrail Cable Installation 38 Walkway Cable Installation 39 Installing the Suspender Cables 40 Laying the Decking 41 Concreting the Cables 42 Protecting the East Bank 43 Protecting the West Bank 44 Official Opening 45 Leaving Uledi 46 Snorkelling at Nkhata Bay 47 Back to Lilongwe 48 Conclusion 49 Acknowledgements 50 Appendices 51 Appendix A – Group Equipment List 51 Appendix B – Personal Clothing & Equip 53 Appendix C – First Aid Kit List 54 Appendix D – Construction Equipment 56 Appendix E – Food List 58 Appendix F – Finances 60 Appendix G – Risk Assessment 62 Appendix H – 2006 Expedition Summary 63 Appendix J – Tambuka Words 64 Address List 64 Bibliography 65 Books 65 Maps 66 Distribution List 66 Bridge Plans – Design sketches 68 Maps C & D – Uledi maps (fold out sheet) -1- IMPERIAL COLLEGE BUILDING BRIDGES 2007 EXPEDITION REPORT Below – Harriet walks the next piece of decking out to be laid. Inset – Naomi slides the suspender cables into position. SUMMARY By Daniel Carrivick OUTCOME This team of five students from Imperial College, London travelled to Malawi to complete the construction of a footbridge across the North Rukuru River at Uledi, on the north western corner of Nyika National Park. This work followed on from the previous expedition in 2006, which surveyed the site, laid down the foundations, and constructed the towers and anchorage for a thirty-seven metre span suspended bridge. The team achieved their aim, much to the appreciation and delight of the community and the national park, who now use the bridge daily to cross the river to collect firewood and patrol against poachers. EXPEDITION SUMMARY This expedition was organised by Naomi Bessey and Daniel Carrivick who were part of the team that travelled to Malawi in the summer of 2006. They were joined by Harriet Kirk, who acted as chief site engineer having helped with the design the previous year, and two other civil engineering undergraduates: Li-Teck Lau and Jumana Al-Zubaidi. The first week was spent in Lilongwe collecting food and equipment supplies while clearing the import duty on the cables, which had been flown out the previous year by airfreight. After several visits to the Malawi Revenue Authority (MRA) and with the help of senior officials from the Department of National Parks & Wildlife (DNPW), the team finally got the permission they required and the import duty was subsequently waived. Having collected the half tonne shipment of cables and accessories from the airport, the team travelled north, stopping overnight at Mzuzu to collect perishable foods, and again at Chelinda to meet park officials, pick up their scout and collect wood from the sawmill. To the teams’ relief the site was in much a similar state as to how it was left ten months previously - just a lot more overgrown. The wet season had brought more rain than normal, but the river had stayed within its banks and did not flood the surrounding area. Work soon began on clearing the site and unearthing the access pits, which had been filled in for safety. Within a few days of arriving in Uledi, one member of the team became ill with a high temperature and feverish symptoms. No improvement was seen over the next few days so the individual was sent to Mzuzu to see a doctor who diagnosed Malaria. A course of drugs were taken and the patient recovered fully within a week. However further tests done back home suggest this person never contracted Malaria. Some thirty people were employed from the community to assist with the completion of the bridge. A new minimum daily wage was adhered to which saw workers pay increase by 23% (real terms) from the previous year. The working day remained the same, from 7:30 am to 4:30 pm with a break for lunch between 11:30 am and 1 pm, over the hottest part of the day. Temperatures often reached the low to mid twenties centigrade and the strong sun was made bearable by the cool river and sometimes strong winds. Daylight hours were from 6 am to 6 pm so it was often dark by the time the team ate in the evening, once all the equipment had been removed from the site, the fire lit and the food cooked. The workers were mainly given the task of collecting materials. Vast quantities of earth were moved to build embankments on the approach to each tower. A soft engineering approach was used to build retaining walls for this earth. This involved filling woven sacks with earth and staking them with metal rods into the ground. Meanwhile sand and gravel were gathered for concreting and boulders were used for armouring the bank and towers. The whole workforce helped to unroll the cables and carry them across difficult terrain to the site. A great deal of manpower was again required to haul the cables across the river. The cables were then fastened once they had been raised into place using a sequence of pulleys and grips. Members of the expedition team used specialist high ropes equipment to fasten adjoining cables and lay the decking. The bridge was left to settle under its own weight before the final adjustments were made and the cables concreted into place. With the bridge out of bounds while the concrete set, work concentrated on clearing the river channel from low branches, protecting the river bank in front of the towers and building up the earth embankments behind the towers. The large felled branches were sectioned and manhandled upstream where they were held in place on the east bank by stakes. The area behind each log was then backfilled with large boulders. These were covered with a steel mesh to hold everything in place forming a new tiered riverbank. Meanwhile the west bank was covered with steel mesh, which was weighed down with some left-over lengths of railway track and pinned against the river cliff with twenty inch long metal stakes driven into the earth. The mesh was designed to hold loose blocks of rock in place to prevent collapse and further erosion of the bank. A last minute rush ensured all the finishing touches were applied to the bridge before the opening ceremony held at 2 pm on Wednesday 25 th July. The chief of Uledi and the senior national park officer from Chelinda both spoke to a large crowd that had assembled, before jointly declaring the bridge open. Officials then crossed the bridge one at a time, followed by the local workers and the rest of the community. Useful tools and leftover materials were then handed over to the chiefs for the community to use in the future. That evening a meal was enjoyed by all and the celebrations went on long after darkness. Having successfully completed the bridge the team headed down to the Lake Malawi via Vwasa Marsh Nature Reserve for a few days of well earned rest and relaxation before returning safely home to England. -2- IMPERIAL COLLEGE BUILDING BRIDGES 2007 EXPEDITION REPORT INTRODUCTION By Naomi Bessey The North Rukuru River divides the community of Uledi, a remote farming community in Northern Malawi, situated on the north western corner of Nyika National Park (maps A & B) . Biosearch Expeditions, who visited the area in 2004, discovered that it was not possible to cross the river during the rainy season. The community was therefore effectively split in two for up to six months every year when the rains came. A bridge would allow the National Park scouts stationed in Uledi to patrol against poachers in the park all year round; villagers would also be able to gain year-round access to the school and markets. In addition, scientific surveys on the National Park’s flora and fauna could be carried out at different times of the year providing more complete data, than at present. In the summer of 2006, a five person expedition team, led by Daniel Carrivick and Naomi Bessey, set out to construct a footbridge across the North Rukuru.