Structural Design of the Station - Coursework Example

Structural Design of the Station Why is steel preferred for columns? Concrete is a common building material in most super structures today. Despite this fact, concrete has some weakness in its property; it is strong in tension but weak in compression. This property makes concrete bear tensile forces but succumb to compression forces. Because of this weakness, steel is preferred for columns. Steel as a column withstands compression better than concrete. This makes steel qualify as our material for column construction in the station. Why did we use steel columns structural parts of the structure? The benefits linked to steel as a composite material for columns are many and economical. Columns made of steel are slender because material used is strong enough o bear dead and live loads subjected to it. Columns made of other types of material like stone and bricks have a larger cross sectional-area than steel. The large cross-sectional area should be proportional to the column’s length. Although a steel column could be stocky, the strength possessed is greater than that of stone. Through design, slender columns are developed. This type of flexibility is not possible for other materials. The bearing capacity of a stocky column is directly proportional to strength of material as well as cross-sectional area. On loading, a stocky column shortens elastically until an elastic limit is achieved. At this point, an increase in exposure to loads leads to a disproportion in length reduced. This is referred to as the yield point of a column. If loads are increased on the column, it automatically collapses. This behavior is prevalent when the column is short in comparison to its size and cross-sectional area. The failure developed in this particular case is derived from steel as a construction material in compression. The axial load capacity is determined from this formula: Column Axial Load Capacity= Yield Stress of Steel during Compression X Column Cross-sectional Area. Practically, such columns cannot be achieved because high strength in steel needs a column that has a small cross-sectional area. This implies that the commonly used steel columns are slender. This characteristic contrasts that of columns made from weak materials. These columns are stocky and possess a large cross-section. Structural failure related to steel columns is buckling. This mode of failure is related to slender columns. Proportionally casted steel columns buckle before steel’s crushing strength. With gradual increment in compressive strength, a value is achieved at the point when the column buckles and deforms perpendicular to its axis and shortens axially in length. This type of load is the buckling load. On reaching the buckling load, steel columns fail as structural elements and can no longer sustain any load. The purpose of column design is to predict that specific load that will make a column collapse. An adequate safety factor is kept in consideration during design. This safety factor must be compared with the applied factor (tatasteelconstruction). EUROCODE 3-STEEL DESIGN Construction process of steel structures is in four stages: design, construction operation and dismantling. Eurocode Design Manuals provide guidance during design stages on Eurocodes through a theoretical background and provisions in the design codes. Eurocode 3 addresses design of steel structures describing the basics of design, properties of material, geometric qualities and tolerances. The code highlights structural analysis of skeletal structures, and the design of members and components. Structural modeling, global analysis and categories of cross-sections are discussed in the code. Internal forces like tension, bending and shear, compression and torsion forces, and their combination exposed to steel members are considered during design (Luís Simões, Rui & Helena 2010, p. 1.1). EUROCODE 6 - Masonry  Eurocode 6 is a set of guidelines to masonry buildings and civil engineering works (except bridges). Its description contains reinforced, prestressed and confined masonry. It is composed of four parts: regulations for reinforced and unreinforced masonry, structural design for fire, selection and masonry works and calculation methods used for unreinforced concrete masonry structures (Roberts, n.d., Pp.2-6). Materials covered in the code are clay, concrete and stone. Configurations based on proportion, perforation directions, thickness among other factors are made. Compressive strength of masonry in the code considers normal strength for masonry and that of mortar. Designs for mortar have changed because of declaration needs based on strength but not mix proportions (www.eurocode6). Software-Statics 2011 Spatial Framework Programme (6 degrees of freedom per node) is used in solving multi-storey reinforced concrete structures, bearing masonry, metal States, wood members, or members of different bodies of composite materials. Eurocode 2(Opl. Concrete) and Eurocode 8 (Earthquake), and and EC1, EC3, EC5, EC6 provide guidelines for design. The software comprises of: The main body; composed of Reinforced Concrete, Structural Steel, Structural Timber, masonry structures, and combinations thereof (promiscuous Agency) Flexible correction, change, delete, add data after the initial introduction, with auto body recognition Identification panels, plates solving, distribution of loads on beams, continuous beams division, Completely automatic with only one option Special type panels: metal, wooden, metal-concrete composite Description of any type column: rectangular, circular, form C or P (elevator) or T-composite sections consisting of an unlimited number of rectangular columns Description of columns, curved walls, curved beams, and curved edges (contours overhangs, etc.) Description ramp height columns and columns of variable cross-section height Description Multi-sloped roofs on the same floor plan (with different ridges, slopes, contours) Special static points: Joints at ends of beams, columns, change braces and beams and adding user-vertical or horizontal loads in columns (beyond recognized by the program) Special Loads automatically created: Temperature of a structure is considered as uniform change in the whole building, per level, in difference and exit. Fibre sizing beams are placed only at the (and length selected by the user) columns or foundations. The design focuses: Snow Wind (lateral, on the facades of the building, taking away the roof) Land impulses (relaxation-EQ) in basement walls. Differential subsidence is derived from drop support. Technical Report of Static and Antiseismic Calculation with the use program of “Statics 2011” EUROCODE 3(PROGRAMME Results) Proposal Design 1. Assumptions [I]. Materials [II]. Vertical Loads a. Permanent b. Variable IV. Ground V. Conditions OF Environment 2. Technical Information of Bearing Construction The building constitutes common manufactured materials, which is the basic bearing construction of the work. It is composed of reinforced concrete and structural steel while fulfillment materials are of glass and bricks. Horizontal parallel plates constitute basic bearing construction of the individual sandals, monolithically connected with crossed joists and walls, individual sandals and binding joists. Construction of fulfilment is considered in the design process because it transports the vertical loads corresponding to basic bearing construction (Knapton 2003, p.109). 3. Methodology of Analysis The analysis realised is based on the following assumptions: 1. The bearing construction is constituted by members of linear deformity. 2. Construction materials are continuous, homogeneous, and linear and follow Hooke’s law of elasticity from manufactures state. 3. The results of analysis are in effect only for small locomotion so that the phenomenon of 2nd order is ignored. 4. Factors of rigidity are calculated in the non deformed bearing construction, while equations of balance are applied for the deformed position of the bearing construction. The bearing construction is solved as a frame in the space with 6 degrees of freedom per free node. This analysis combined with the method of Locomotion’s. The program “manufactures” the general registration of rigidity of bearing construction and the total registration of charges of the construction. It is created from a linear system of equations (equations of balance). The resolution obtained is equated to locomotion and rotation of the free nodes. An exception is made for the corresponding nodes of the reversed foundation. The corresponding nodes of the foundation can also be cancelled to attain corresponding degrees of freedom. Locomotion of the nodes assists in determining intensive sizes (3 forces and 3 propensities) at the end of each member. Inversion of registration of rigidity is developed with the numerical method Cholleski-Skyline. 3. 1 Slabs Czerny method is used to calculate intensiveness of slabs. The reactions of uniformly loaded slabs are calculated according to a DIN 1045, with geometrical division of the surfaces so that they are distributed as charges of planning in parametric joists(or slabs).The maximum and minimum moments of opening are also calculated (Knapton 2003, p.37). 3.2 Foundations The action of design were calculated in terms of combination of the relation Efd = Efg ± [g] Rd*[O]*Efe Satisfactory intensity for the foundations is in dimensions. This should be received by the ground. Caution is taken to avoid overshooting the bearing capacity of the ground. The moment the bearing is transferred on the ground (which is considered as steadfast support) because of constructional eccentricity and seismic moment, a rotation is triggered in the foundation. This rotation is distributed in elements of rigidity (binding joists and ground) reflected in the Indicator of Resistance of each rotation. Control occurrence at the base column for the moment (ροπή) happens from the turn of the sandal. The resolution of sandals and beams originates from using ground idealisation. This is the model of Winkler (Knapton 2003, p.109). 4. Dimensioning 4.1 Action OF Designing The action of planning is calculated as follows: Sd = 1.35*G + 1.50*Q + 1.50*S Sd = 1.35*G + 1.50*Q + 1.50*W Sd = 1.35*G + 1.35*Q + 1.35*S + 1.35*W Sd = 1.0*G + [ps]2*Q + 0.3*S ± E Where G: Permanent, Q: Mobile, S: Snow, Wa: Wind, E: Earthquake, and The Ψ2 is fixed according to the EC1 4. 2 Elements from Reinforced Concrete Total Resistance method is used for dimensioning. To achieve this, the bearing capacity and the functionalism of the bearing construction in critical cross-sections of all members had controls. The controls countered the revised Regulations for Reinforced Concrete in the following ways: a) Through marginal situations resistance of equitable intensive sizes: moment of bending axial force of slabs, sandals of joists etc b) Through stresses due shearing: twisted beams, binding joists etc c) Through perforation of sandals d) Through buckling and bending of vertical elements and e) Through marginal situations of functionalism of cracking and deformities, arrows of bending (Knapton 2003, p.5). Restriction of big deformities is achieved in most cases through application of constructional provisions of Regulation of Concrete and Steel. It is important to acknowledge that all special controls imposed rely on the new provisions of Eurocodes for all types of elements in construction (multisoft). 4.3 Elements from Steel All dimensions comply with Eurocode 3. Methods stated in the Eurocode were also used for the required controls in bending, shearing, connections and other related issues. Figure : Steel columns ( Statics 2011) Figure : Static analysis ( Statics 2011) Bibliography Knapton, J. (2003). Ground Bearing Concrete Slabs: Specification, Design, Construction and Behaviour. Thomas Telford Publishing Co. Ltd. London. Luís Simões da S., Rui S., Helena G. (2010). Design of Steel Structures; Eurocode 3 Design of Steel Structures, Part 1-1: General Rules and Rules for Buildings. European Convention for Constructional Steelwork (ECCS), Portugal. No Author (n.d.). Eurocode 6: Design of Masonry Structures. Web: http://www.eurocode6.org. Retrieved on 05/05/2012. No Author (n.d.). Behavior of structural members in compression. Web: http://www.tatasteelconstruction.com. Retrieved on 05/05/2012. No Author (n.d.). Statics Eurocode. Web: www.multisoft.gr. Retrieved on 05/05/2012. Roberts, J.J. (n.d.). How to design masonry structures using Eurocode 6: Introduction to Eurocode 6. The Concrete Centre, UK. Read More