Week 6: Case Study -‐ Structural Concept Name: Wenjie Cai Case Study: The Queens College Members: Stephen Kai-‐Hang Yuen, Scott Andrew Braithwaite, Kosta Archimandritis
1. Description/Classification of Structural Systems a) Foundation & Footings Footing is the first step of construction, which is the supporting layer of the structure of the building. Every building needs foundation and footings. Their functions are to transfer loads (both dead loads & live loads) to the ground and to resist frost. In the construction drawings, the footings include piles/piers, concrete slab and existing slab in place. b) Primary Structure (Horizontal and Vertical) The primary structural system is defined by CASE in the National Practice Guidelines for the Structural Engineer of Record as "the completed combination of elements which serve to support the building self weight, the applicable live loads, which are based on the occupancy and use of the spaces, and the environmental loads, such as wind, seismic and thermal." In the Queens College, the primary structure includes the precast concrete panels. c) Secondary Structure It is defined as "elements that are structurally significant for the function they serve but do not contribute to the strength and stability of the primary structure". For example, the secondary galvanized steel beam.
2. Graphic Structural Diagrams a) Foundations & Footings
This graph shows the location of the piers of the footings. b) Primary Structure (Horizontal & Vertical)
This is the pre-‐cast concrete panel of the primary structure. c) Secondary Structure
This is the steel beam for the secondary structure. 3. Identification, description and location of structural materials a) Precast Concrete Panel Pre-‐cast panel are mainly used as walls or footings and structure materials for the primary structure in the Queens College case.
b) Steel Steel is being used for beam that supports the building as secondary structure. It is used for different structural systems in this case as well, for example, roofing system & wall system.
c) Timber Timber in this case is mostly used as rafters of roof system.
d) Bricks Clay bricks are used in this case as walls or anchor.
4. Identify 3 Structural Joints a) Footing Pre-‐cast Panel Joint
In this case, bolts are used for connecting the cast in plate together so that the pre-‐cast concrete panels are fixed. b) Steel beam to pre-‐cast concrete panel joint
This is the joint of the steel beam and pre-‐cast concrete panel. c) Pre-‐cast Concrete Panel Joint
5. Identify and explain the use of different structural fixings a) Weld A weld is a joint where two or more pieces of materials have been welded together. Two or more pieces join together by melting and fusing. The base materials are melted and added to the filler materials. This will become a strong joint once it cools down. It is mostly being used for joining metals together, for example the structural steel members. In the construction of the Queens College, continuous fillet weld is used in the steel beam to pre-‐cast concrete panel joint and also the pre-‐cast concrete panel joint.
b) Concrete Concrete is made by mixing cement, water, aggregates and admixtures. Concrete is strong in compression but has lower tensile strength so it also needs steel reinforcement. It can be formed in almost any shape and widely used in constructing, such as wall and floor systems as it can withstand natural disasters. In this project, pre-‐cast concrete panels are used for the primary structure.
c) Bolt Bolts are metal pins or rods that usually having a head at one end. It designed to be inserted through holes in assembled parts and secured by a mating nut. Bolts provide strong bonds so that the constructions do not break under pressure. In this project, bolts are used in the footing pre-‐cast concrete panel joint and also the steel beam to pre-‐cast concrete panel joint.
d) Screw Screws and bolts are both externally threaded headed fastener. The difference between screws and bolts is that bolt is used in conjunction with a nut; and screws are tightened by applying torque to the head.
e) Nail A nail is a slim, pin-‐shaped fastener. It has a point on one end and a head on the other. Using nails is an effective way of fixing or joining pieces of softwood. They are usually driven into the material by a hammer. It holds the materials together and resists forces perpendicular to them.
6. Sustainability and Environmental Analysis a) Carbon Footprint ‘ The amount of carbon dioxide or other carbon compounds emitted into the atmosphere by the activities of and individual, company, country.’ (Dictionary.com 2013) If the building emit large amount of carbon compounds, it has negative impacts on the environment. This concept is linked to the distance of the materials being transferred. If most of the materials were from places that are far away from the construction, it would be unsustainable. b) Embodied Energy "The quantity of energy required by all of the activities associated with a production process, including the relative proportions consumed in all activities upstream to the acquisition of natural resources and the share of energy used in making equipment and in other supporting functions i.e. direct energy plus indirect energy." (Treloar, 1994). This is also related to the materials as well. It is not only depends on the distance transfer, it also depends on the energy needed to construct the building. c) Recyclability Recyclability is the ability of an item to be reused. In construction, this means the ability of the structural materials to be recycled. If the building is recyclable, it means that it is more sustainable that it does not waste the resources.
7. Economics Implications of decision
http://www.recampus.com/documents/book15_c01.pdf http://www.structuremag.org/article.aspx?articleID=321 http://dictionary.com/