This work looks at how the North Hall Library building resists all vertical and horizontal loads and transfers these to the subsoil. The second part of the work looks at the technical descriptions for the buildings elemnents. The North Hall Library building was built about 100 years ago but has been adapted. It was designed to accommodate a different use but now provides a place for books shelves and work stations for students. The building is now a two-storey as a result of a mezzanine floor being incorporated. The design allows the library to serve the needs of its population of users. In terms of access and means of escape, the building has 4 main entrances leading into the main library, and two leading to the outside of the building. There are also two staircases that leads onto the mezzanine floor.
3.0 Approach
This work looked adopted a desks and field study approach and looked at Building Case Studies and a range of sources including internet sites and publications by professional bodies as well as investigating the said building.
4.0 A load path diagram and technical description of the building's
structural form
insert load path diagram
Dead and live loads includes the wind pressure and the weight of the building and the mezzanine floor, book shelves, books and PC's and work stations as well as students which are all constantly adding to the load. The building has a sloping roof structure that sits on top of the external walls. The structure has been designed to give a clear span so that there is flexibility in useage of space without the interefering with columns and beams or wall structure. The load end up coming down the external wall and the timber structure transfers the whole of the roof load and horizontal load from the wind into those walls. This is why the timber is shaped the way it is. It simply transfers the the load and gives a transition between the horizontal and the vertical wall. The building is reasonably stiff by virtue of the ties so that when the wind blows it will be trying to lift the roof up but the stiffness will resist all that. It transfers the wind load into the walls. The external wall is reinforced by having piers related to where the trusses come down so that there's a bit of extra stiffness and thickening in that location to take the load. The positions of the timbers are such that they come down and help transfer the load that the timber roof is bearing into the brickwork since it has got more bricks to transfer the load. The walls do not fall over because they are tied together by the truss sitting on top of them. The trusses adds some stiffness to the whole structure. The building is designed in such a way that it accomodates all these loads and doesn't allow the building to settle or fall down.
5.0 Technical descriptions for the elements of the building
It is difficult to talk about the foundation because the foundation isn't visible however this is the kind of building that sits on a strip footing which if builng built now will use concrete and brickwork of about 1 metre below ground depending on the ground condition.
With regard to external walls, it is a facing brick. It is a good English bond. A solid brickwork is assumed because the building isn't a modern building. In effect the building will not have a cavity. This is consistent with the age of the building since cavity walls did not become common till the 1940's and 1950's. the solid wall is assumed to have a thickness of more than one brick. The interior seems to have a finish and it is assumed that due to the age of the building, the original plaster of sand and cement with gypsium has been removed and been replaced with something else.
The roof structure is of timber with trusses and joists. Timber rafters coming down which sits on purlins. The roof finish looks concrete but it looks like clay tiles. The tiles are plain and not curved nor bent.
The windows are clearly painted timber of softwood form pine tree which are used extensively for carpentry work this is consistent with the use of softwood which were predominant when the building was being built. The ground floor is a solid concrete floor.
The internal mezanine structure with a staircase at each end looks as though it is completely independent of the main building structure and doesn't interfere with the structure at all and so taking it away for the shell of the building to accomodate a new use will not let the building fall down. For the mezanine floor, it is assumed that there's a base plate so that load is transfered to the concrete over a much wider area. It is assumed that the concrete floor was broken up to put in a concrete base underneath big lump of concrete for the whole lot of the mezanine to sit on.
The heating system comes from radiators located alongside the internal walls on the ground floor.
6.0 Conclusion
This work has looked at how the North Hall Library building resists all vertical and horizontal loads and transfers these to the subsoil. It was found that the external walls go down to the foundation and all the loads on the building is transferred to the foundation whether the load is vertical or horizontal. The load is transferred to the foundations based on the structure of the building. The load on the floor where people walk and where the book shelves and books are is transferred to the structure which spans between the load bearing walls. It gets transferred to the external walls by the floor and gets into the building. The floor has got an integral strength because of the way it is made. As a result the load is transferred to the end because there is no where else for it to go so its own weight and the loads imposed on it is transferred to the building at the end which bring them all down the external walls and down to the bottom where the is contact with the ground through the foundations. In addition it was found that the timber roof are joined up in the building in such a way that loads are transferred where the timber roof meet meets with the external wall. The load travels down the brick work. Each brick work sits on top of the other and the load is transferred through each brick till it gets to the foundation which is in contact with the ground. The foundation is strip footing and so the load is transferred further down to a sub soil which takes the load. The walls are thick enough to resist being blown off by wind. The second part or this work looked at technical descriptions for the elements of the building it was assumed that the solid brickwork building sits on a strip footing foundation. Good quality English bond has been employed and the other element of the building explored was the roof structure which turned out to be of timber with trusses and joists sitting on purlins. The roof finish are plain tiles that are not curved nor bent. The windows are of softwood timber and a mezanine structure with a base plate stands and looks as though it is completely independent of the main building structure.
References
Stern N. The Economics of Climate Change – The Stern Review, Cambridge University Press 2006. Online – http://www.hm-treasury.gov.uk.
Intergovernmental Panel on Climate Change 2007: The Physical Science Basis – Summary for Policy Makers, Geneva, Switzerland: Intergovernmental Panel on Climate Change (2007). Online – http://www.ipcc.ch)
Tyndall Centre. How Can Business Adapt To Climate Change 2004.
CIBSE, Climate Change and the Indoor Environment: Impacts and Adaptation.
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