AN ASSESSMENT OF SAFETY PRACTICE IN THE USE OF SCAFFOLD
Chapter One:
Introduction
1.1. Background
Shores are temporary structured used for supporting structures under construction. Scaffolds are temporary elevated platforms built to facilitate the work of laborers and use of materials, mostly at higher than ground level elevations.
Shoring and scaffolding in one form or another has been used since humans moved from single story huts at ground level to taller structures. From times immemorial, shoring and scaffolding has been used in ancient Egypt to the modern world. Ancient Egypt constructed some of the most marvelous structures like the Pyramids and statues. Scholars are still baffled as to how the Egyptians built the pyramids. Some theories suggest that a series of dirt ramps and wooden scaffolding allowed each block to be hauled into place [1] . Scaffolds were also used to carve out statues around a big sized rock from the top to the bottom. The Berlin Foundry Cup depicts scaffolding in ancient Greece, early 5th century BC. Egyptians, Nubians and Chinese are also recorded as having used shoring and scaffolding like structures to build tall buildings [2] . Ancient Ethiopians also curved and erected monolithic obelisks, Lalibela rock-hewn churches, Fasil Ghebbi, castles and many more structures. The largest monolithic stelae ancient human beings ever attempted to erect survive in the town of Aksum dating between the 3rd and 4th centuries AD. The largest standing obelisk rises to a height of over 23 meters and is exquisitely carved to represent a nine-story building of the Aksumites. The largest obelisk of some 33 meters long lies where it fell, perhaps during the process of erection [58] . Nevertheless without the use of shoring and scaffolding systems curving and erecting these structures would have been impossible. Early shoring and scaffolding was made of wood and secured with rope knots [2] .
In the far eastern countries like China and India, bamboo is used as scaffolding material. Many famous landmarks, notably The Great Wall of China, were built using bamboo scaffolding. Bamboo is flexible in nature yet it is strong and durable too and that gives the structures a good deal of strength. Two or more bamboo poles are bound together by ropes so that they do not slip or slide [2] .
The modern shoring and scaffolding started in the early 20thcentury when metal fixings were introduced in place of rope. Later on, metal pipes began to be introduced instead of timber poles with standardized dimensions, allowing for the industrial interchangeability of parts and improving the structural stability of the shoring and scaffolding, which brought about a revolutionary change in the construction of very tall buildings. Metallic shoring and scaffoldings are the main pillars of the modern shoring and scaffolding business. The use of diagonal bracings also helped to improve stability, especially on tall buildings. The first frame system was brought to market in 1944 and was used extensively for the postwar reconstruction [2] .
Due to the large amount of developments undertaking throughout the years, shoring and scaffoldings are found everywhere. Shoring and scaffolding play major role in building construction. They present an important part in construction especially building operations at height. Scaffolding has a variety of applications in the construction industry. It is used in new construction, alteration, routine maintenance, renovation, painting, repairing, and removal activities. Scaffolding offers a safer and more comfortable work arrangement compared to leaning over edges, stretching overhead, and working from ladders. Scaffolding provides employees safe access to work locations, level and stable working platforms, and temporary storage for tools and materials for performing immediate tasks
Shores and Scaffolds are an integral part of construction operations in any field of construction especially for high-rise construction. While scaffolding is often considered to be of lesser importance within the overall project requirements, it does account for a considerable amount of labor-hours [4] .
Now days there are variety of shoring and scaffolding systems are available around the world. Selecting the right type of shoring and scaffolding, which satisfies the budget, the time constraints and maintaining safety of the work place, becomes more concern around the construction industry.
Shoring and scaffoldings are usually constructed using metal tubes, Bamboo and timber in different countries. In Ethiopia shoring and Scaffoldings are usually constructed using Eucalyptus wood but currently the use of metal and Bamboo is emerging around Ikeja building projects. It can be understood that due to the material properties of eucalyptus wood a systematic design of eucalyptus scaffold is not available.
1.2. Statement of the problem
Nowadays, everything is about speed and all projects have to be completed within a short time frame. For multi-story buildings the traditional eucalyptus wood shoring and scaffolding systems are neither suitable nor meeting any safety parameters. Because eucalyptus wood is a natural material it has inconsistent material properties as a result systematic design of eucalyptus wood shoring and scaffolding systems are not available. It is strongly relied on the experience of the carpenter to make judgment when executing the work. Consequently it leads to uneconomical and unsafe practices. Despite these short comings, eucalyptus wood shoring and scaffolding systems have been dominating the Ethiopian construction industry. Recent concerns about safety, increasing height of buildings, operating cost and flexibility constraints are now requiring innovation in shoring and scaffolding systems In Ikeja.
Different literatures have been recommending replacing the traditional Eucalyptus wood shoring and scaffolding systems with currently available technology and also tried to introduce alternative shoring and scaffolding materials like bamboo [5, 6] . In order to make these necessary changes possible first there should be a clear understanding of the current practice of shoring and scaffolding systems and extensive knowledge of affecting factors in selection of scaffolding systems. There are still inadequate acknowledgements and few research studies to either understand the current practice of shoring and scaffolding systems or contractors approach how they select the existing shoring and scaffolding systems.
1.3. Research objective
The objectives of this research work are following.
- To assess methods and materials used in erecting shoring and scaffolding systems in building construction projects around Ikeja.
- To identify critical factors for selection of shoring and scaffolding systems in building construction projects around Ikeja
- To make comparison of cost, time, safety, operation and application of the eucalyptus wood with currently available shoring and scaffolding materials around Ikeja.
1.4. Scope of the research
This research focused only on shoring and supported scaffolding systems used in building construction projects in Ikeja. The research mainly focused on shoring which are used in slab and beam concrete construction, and supported scaffolding systems, which are built from the base upwards to provide temporary access and working platforms on elevated areas. It doesn’t include related issues like form work.
AN ASSESSMENT OF SAFETY PRACTICE IN THE USE OF SCAFFOLD
