2.1 INTRODUCTION TO ANALYSIS AND DESIGN 2.0 ANALYSISI AND DESIGN 2.1 INTRODUCTION TO ANALYSIS AND DESIGN PREPARED BY : NOR AZAH BINTI AZIZ KOLEJ MATRIKULASI TEKNIKAL KEDAH

2.1 Introduction to Analysis and Design Learning Outcomes : At the end of the lessons, students should be able to: Identify engineering data for analysis and design. Identify approaches to analysis and design.

STRUCTURAL ANALYSIS AND STRUCTURAL DESIGN

Structural Analysis Structural analysis is the determination of the effects of loads on physical structures and their components. Structures subject to this type of analysis include all that must withstand loads, such as buildings, bridges, vehicles, machinery, furniture, attire, soil strata, prostheses and biological tissue. Structural analysis incorporates the fields of applied mechanics, materials science and applied mathematics to compute a structure's deformations, internal forces, stresses, support reactions, accelerations, and stability.

Structural Analysis The results of the analysis are used to verify a structure's fitness for use, often saving physical tests. Structural analysis is thus a key part of the engineering design of structures.

Structural Design “Structural design can be defined as a mixture of art and Science, combining the engineer’s feeling for the behavior of a structure with a sound knowledge of the principles of statics, dynamics, mechanics of materials, and structural analysis, to produce a safe economical structure that will serve its intended purpose.” (Salmon and Johnson 1990)

Classification of Structure Important for a structural engineer - to recognize the various types of elements composing a structure and to be able to classify structures as to their form and function. Structural elements are tie rods, rod, bar, angle, channel, beams, and columns. Combination of structural elements and the materials from which they are composed is referred to as a structural system. Some of structural systems are Trusses, Cables and Arches, Frames, and Surface Structures.

Structural Elements Structural Elements Such members or elements include the following: Trusses Beams Columns Shear Structural Elements Steel Rods Connection Elements  

Structural Elements Engineering Systems Structural Elements - Bending Structures

Structural Elements Engineering Systems Structural Elements – Compression Structures

Structural Elements Engineering Systems Structural Elements – Trusses

Structural Elements Engineering Systems Structural Elements – Tension structures

Structural Elements Engineering Systems Structural Elements – Shear Structures

Engineering System Engineering structural systems are of variety that they defy any attempt to enumerate them. The many problems which arise in their design has prompted engineers to specialize in the design of particular structure or groups of related structures. A complete design requires the coordinated efforts of several branches of engineering.

Engineering System KLCC TWIN TOWER

Engineering System Engineering Systems LONDON BRIDGE

Engineering System Engineering Systems FRAME STRUCTURE

Engineering System Engineering Systems HOOVER DAM Arizona-Nevada Border Near Las Vegas

Engineering System Engineering Systems TRANSMISSION TOWERS

Engineering System Engineering Systems RETAINING WALL

Engineering System Engineering Systems AIRPORT AND HIGHWAY LANDING STRIP

Analysis Versus Design Structural Analysis Structural Analysis is the prediction of the performance of a given structure under prescribed loads and/or other effects, such as support movements and temperature change.   Structural Design Structural design is the art of utilizing principles of statics, dynamics and mechanics of materials to determine the size and arrangement of structural elements under prescribed loads and/or other effects.  

Analysis Versus design Design Procedure Design procedure consists of two parts: i) Functional Design - ensures that intended results are achieved such as adequate working area, elevators, stairways, etc. ii) Structural Framework Design Structural framework design is the selection of the arrangement and sizes of structural elements so that service loads may be carried.

Analysis Versus design

Definition of Structure A structure is an engineering construction that supports dead and imposed load without noticeable deformation besides fulfilling its functions.

Types of structure Types of Structure i) Mass Structure - depends on its mass to support loads. - e.g earth dam and rock-filled dam ATATURK DAM, TURKEY

Types of Structure ii) Framed Structure - structure built according to specific components. - a component that carries load transfer it to another component, n continuously down to the lowest component geometrically below.

BUILDING STRUCTURAL COMPONENTS Column Roof Beam Foundation Floor Slab Wall

Design Method Design based on design standards Bs 8110 are based on Limit State Method. This method is designed to set the structure should be very safe and is suitable for use, ie. it does not reach the age limit during the service. when elements in the structure can not function according to its use, it is said to be approaching the limit ( limit states).

Design Method Limit states for reinforced concrete structure are; i) Durability durable to environmental exposures that cause defects or corrosion in reinforced concrete ii) Fire resistance Resistance to fire exposures according to standard stated in BS8110 iii) Ultimate limit State situation where the entire structure or integral element of failure such as collapse or fall iii) Serviceability Limit States Circumstances occurs when the structure becomes inappropriate or uncomfortable to use, such as cracking, the deflection and vibration in excess of the prescribed standards. iii) Special Limit States the damage or failure caused by loading or unusual sources such as earthquakes, explosions, etc.

Design Method

Ultimate Limit State Can be divided into; Loss of equilibrium occurs when the structure being tilted / crooked or slippage occurs which causes the equilibrium of forces can not be determined Rupture structural element that breaks / breaks that cause the structure tends to collapse as part or full collapse. Progressive Collapse occurs when part of the load support element or elements beyond the limits of failure during the construction process that could cause the entire structure installment progressively damaged and collapsed. progressive collapse can be prevented or delayed by binding a critical part or other alternatives for distributing the load.

Formation of plastic mechanism Ultimate Limit State Can be divided into; Formation of plastic mechanism situation where the reinforcing steel reaches yield point and form a plastic hinge that causes the loss of structural stability. Instability failure occurs due to excessive displacement or buckling of structural instability. Fatigue element failure occurs when the cyclic load is continuous imposed on him.

Serviceability Limit State is taken into account for the normal work of a structure in which the deflection and cracking that occurs must not exceed the limits described. Excessive deflection may cause the structure is not fully functional. can be determined by observation / continuous monitoring Excessive Cracking typically, the reinforcement of concrete will not be fully functional as long as the measure for concrete cracks do not exceed the standard. However, cracks causing leaks and corrosion of the reinforcement occurs. Excessive Vibration For concrete structure, there are vertical vibration, lateral vibration and torsion vibration. Rarely happen in reinforced concrete.

Design Method Reinforced concrete structures designed to meet the ultimate limit state and checked for serviceability limit state. It is important because the main function of the structural elements of the building is to support the load without endangering the occupants.

Loads In order to design a structure, it is necessary to determine the loads that act on it. The design loading for a structure is often specified in building codes: - general building codes - design codes engineer must satisfy all the codes requirements for a reliable structure.  

Loads The structure of a building is the part which is responsible for maintaining the shape of the building under the influence of the forces to which it is subjected. A building must be designed to safely withstand the most severe combination of forces or loads likely to be applied during its lifetime.

Structural principles - Loads The design loading for a structure is often specified in building codes: - general building codes - design codes engineer must satisfy all the codes requirements for a reliable structure.   use the unit kilopascals (kPa) to measure stress and pressure, and kilonewtons (kN) to measure forces and loads. Note: 1 kPa = 1 kN/m2

Primary loads Primary Load Introduction There are three primary loads which a structure must resist: dead load live load wind load.

Primary loads – Dead Load Dead load on a structure ; - the result of the weight of the permanent components such as beams, floor slabs, columns and walls. - these components will produce the same constant 'dead' load during the lifespan of the building. - are exerted in the vertical plane. Dead load = volume of member x unit weight of materials By calculating the volume of each member and multiplying by the unit weight of the materials from which it is composed, an accurate dead load can be determined for each component.

Primary loads – Dead Load The different components can then be added together to determine the dead load for the entire structure. Table 1: Dead load comparisons of various materials Material Unit weight kN/m3 Plain concrete 23.5 Reinforced concrete 24 Glass 25.5 Mild steel 77 Hardwood 11 Softwood 8 By calculating the volume of each member and multiplying by the unit weight of the materials from which it is composed, an accurate dead load can be determined for each component.

Dead Load

Primary loads – Dead Load Volume of beam 10.0 x 0.6 x 0.3 = 1.8 m3 Unit weight of reinforced concrete = 24 kN/m3 Therefore, dead load of beam = volume x unit weight = 1.8 m3 x 24 kN/m3 = 43.2 kN

Example: A 125-mm thick brickwall is constructed along a beam. The clear height of the wall is 2.7m. Assuming a wall density of 1800 kg/m3, calculate the weight of the wall on the beam in kN/m. 125mm 2.7m

Answer: Weight = density x gravity =1800x9.8 =17.64kN/m3 Area cross (section) = 2.7x0.125 = 0.3375m2 Weight in kN/m = 17.64kN/m3 x 0.3375m3 = 5.96 kN/m

Primary loads – Live Load All unfixed items in a building - such as people and furniture result in a 'live' load on the structure. Live loads are; - exerted in the vertical plane. - variable as they depend on usage and capacity By calculating the volume of each member and multiplying by the unit weight of the materials from which it is composed, an accurate dead load can be determined for each component.

Primary loads – Live Load For example; - the live load for a floor in a house is given as 1.5 kPa compared to a dance hall floor live load of 5.0 kPa. - It is reasonable to expect that a dance hall would have more people in it than a house. Live loads for floors as per building usage Uniformly distributed load kPa or kN/m2 Houses 1.5 Flats, apartments, motel bedrooms 2.0 Offices 3.0 Workshops 5.0 Parking, vehicle > 2.5 t Hospitals, school assembly areas with fixed seating Dance halls, bars, lounges Table 2: Live load comparisons

Live Load

Primary loads – Live Load Area of floor = 6.0 m x 4.0 m = 24 m2 Live load rating of a house = 1.5 kN/ m2 Therefore, live load of floor = 24 m2 x 1.5 kN/ m2 = 36 kN

Primary loads – Wind Loads I Wind loads have become very important in recent years due to the extensive use of lighter materials and more efficient building techniques. A Victorian era building with heavy masonry, timbers and slate tiles will not be affected by the wind load, but the structural design of a modern steel clad industrial building is dominated by the wind load. By calculating the volume of each member and multiplying by the unit weight of the materials from which it is composed, an accurate dead load can be determined for each component.

Primary loads – Wind Loads I Wind blowing against the building results in positive pressure which pushes against the building. A vortex results in negative pressure which pulls at the building. By calculating the volume of each member and multiplying by the unit weight of the materials from which it is composed, an accurate dead load can be determined for each component.

Primary loads – Wind Loads I Wind acts both on the main structure and on the individual cladding units of a building. The structure has to be braced to resist the horizontal load and anchored to the ground to prevent the whole building from being blown away if the dead weight of the building is not sufficient to hold it down. By calculating the volume of each member and multiplying by the unit weight of the materials from which it is composed, an accurate dead load can be determined for each component.

Primary loads – Wind Loads I Because of this, careful placement of bracing or other means of maintaining stability is necessary. It is also important to tie the roof materials to the supporting battens or rafters. By calculating the volume of each member and multiplying by the unit weight of the materials from which it is composed, an accurate dead load can be determined for each component.

Primary loads – Wind Loads 2 Wind load is considered to be dynamic as it varies greatly in intensity from time to time. Wind loads are very different to dead loads and live loads. Wind loads typically act laterally. A force acting laterally is acting in a sideways direction on walls and may act up and down on roofs.

Loads Types of Loads 1. Dead loads 2. Live loads 3. Impact 4. Wind loads 5. Snow loads 6. Earthquake loads 7. Hydrostatic and soil pressure 8. Thermal and other effects  

Characteristic Load Generally, the load may not be assessed accurately. Estimation of loads support by the building must be based on estimated average costs to avoid wastage.

Characteristic Load 1) Characteristic dead load, gk The load that is applied permanently throughout the design life. not vary much from the estimated value . E.g; self weight of structure element, finishing, equipment such as air-cond., water tank, piping, etc.

CHARACTERISTIC LOAD Characteristic Load 2) Imposed load, qk The load that is applied temporarily and may vary with time in terms of position and magnitude. E.g; human, furnitures, stored material, machineries and other equipment. Cannot be calculated precisely.

CHARACTERISTIC LOAD Characteristic Load 3) Wind Load, Wk It is considered in design to overcome lifting effect. Depends on location, form, building dimension and wind velocity of the area.

DESIGN LOAD Equation : Design load (Factored Load) = characteristic load x ∂f ∂f = a partial safety factor for load. Loads acting on a structure normally consist of combination of several load types. :- dead and imposed load = 1.4 Gk + 1.6 Qk :- dead and wind load = 1.0 Gk + 1.4 Wk

Load analysis distribution and path RAFTER PURLIN GROUND SLAB STUMP FOUNDATION COLUMN ROOF BEAM ELEVATED SLAB ROOF SHEET GROUND BEAM WALL