2 INTRODUCTIONAs architects and the building industry continue to design and build structures that vary in type, design, materials, and building methods, it has become increasingly important that members stay familiar with both basic and new concepts of building construction. Construction methods are constantly being replaced by new and more efficient and cost effective methods to construct buildings.
3 SUBSURFACE INVESTIGATIONS The purpose of characterizing subsurface conditions is to determine if the soils beneath a facility exhibit properties that ensure the facility will remain stable under static and seismic conditions during construction and operation and after it is closed.A complete comprehensive soil stratigraphy should be developed that will adequately characterize the lateral and vertical extent of all soil units beneath the proposed facility.Characteristics to be measured include, but are not limited to, shear strength, liquefaction potential, compressibility, phreatic surface elevations and the water content of the soil materials
5 SITE INVESTIGATIONSite Investigation is the gathering of the information about the proposed location of a project, e.g. highway or buildings.
6 The Purpose of Site Investigation The site investigation is aimed at providing sufficient reliable subsurface information for most economical, satisfactorily safe foundation for the proposed structure.The site investigation should reveal sufficient subsurface information for the design and construction of a stable foundation safe from both collapse and detrimental movements.
7 The Scope of Site Investigation TopographySoil profileGround-water condition
8 The Stages of Site Investigation In general, a site investigation program should comprise four stages, i.e. :Desk study and site reconnaissance,Preliminary ground investigation,Detailed ground investigation
9 Desk study and site reconnaissance The desk study is the first stage of the site investigation process which involves researching the site to gain as much information as possible, both geological and historical.A good starting point is to use Ordinance survey maps which allow the selection of the site by obtaining accurate grid reference through the maps.In addition to present maps, old maps are used to gain historical information such as former uses of the site; concealed mine workings; in filled ponds; old pits; disused quarries; changes in potential landslide areas, etc.
10 The source of information that useful in desk study: Geological mapGeological maps are probably most important source of information as these give and excellent indication of the sort of ground conditions like to be encountered.Aerial photographyAerial photography is another extremely useful source of information on topography and ground conditions.Records of previous investigationRecords of previous investigation reports also helpful in a desk study. The many sources of site investigation data include previous company and Public Works Department.
11 The reconnaissance phase of a site investigation This site investigation is done through a site visit or walk-over survey.Important evidences to look for are site lay out, surface condition, climate and hazards water levels, etc.Generally the desk study and reconnaissance is aimed at the feasibility study of the being planned.If the desk study shows that the site is feasible for the structure, then preliminary investigation should follows.
12 Preliminary Investigation Preliminary Investigation is aimed at predicting the geological structures, soil profiles and the position of ground water table by geophysical method or by making a few boreholes.The investigation should give information on the existence on ground structures that may need closer examination: for example,The extent of disturbed strata,The location and extend of natural cavities and mine workings.Fractures and river crossings or alluvial areas that may have buried soft material or pet, their liability to cause subsidence, surface movements or instabilityInformation on suitability of soil for fills work, ground water condition and the possibility of flooding should be provided at this stage.
13 Detailed Investigation At this stage, the extent of the test, number and depth of boreholes, selection of appropriate equipment for field testing and the choice of laboratory testing are made.Soil exploration consists of three steps:Boring and in-situ testing,Sampling,Laboratory testing.
14 MonitoringMonitoring during construction and maintenance period is required whether the expectations of the proceeding investigation have been realize.No one can ensure that the soil parameters used for design is the most representative of the soil conditions at the site unless the response is observed.Field observation can help for early diagnosis and redemption of any problem that might be encountered during construction.Among the measurement made during the monitoring stage are the settlement, displacement, deformation, inclination, and pore water pressure.
15 Steps of Soil Exploration BORINGSoil borings are the most common method of subsurface exploration in the field. A bore hole is used to determine the nature of the ground in a qualitative manner and then recover disturbed and undisturbed samples for quantitative examination.Some types of borings are hand/mechanical auger borings, wash borings, percussion drilling, rotary drilling, and core borings. An auger is a screw-like tool used to bore a hole.Some augers are operated by hand: others are power operated
16 Hand/Mechanical Auger Hand augers may be used for boring to a depth of about 6 m.Power augers may be used for boring to a depth of about 10 to 30 m.As the hole is bored a short distance, the auger may be lifted to removed soil. The removed soil can be used for field classification and laboratory testing, but it must not be considered as an undisturbed soil sample.Power auger set with a drill rig can be used to obtain samples from deeper strata. Some rigs can be used to drill a hole to 100 m depth.
17 Wash BoringWash borings consists of simultaneous drilling and jetting action. A hole is bored through a casing by using a drilling bit.Jetting action is accomplished by pumping water downward through the drilling bit to soften the soil. Samples taken using the wash boring methods are disturbed sample.
18 Percussion DrillingPercussion Drilling is the process of making boreholes by striking the soil then removing it.The tools are repeatedly dropped down the borehole while suspended by wire from the power winch.Water is circulated to bring the soil cuttings to the ground surface.A casing and a pump are required to circulate the water.
19 Rotary DrillingRotary Drilling uses rotation of the drill bit with the simultaneous application of pressure to advance the hole.This method is the most rapid method of advancing a hole in soil and rock.Drilling mud may be needed to prevent soil cave-in.Sample obtained from drilling by this method is relatively less disturbed as compared to samples obtained by the preceding methods.
20 Auger boring Power drills Boring toolsAuger boring Power drills
22 GENERAL REQUIREMENTS OF FOUNDATION:- The only requirement is that it should not fail i.e. it should work efficiently under all conditions of working.Failures are of two types;Bearing capacity failure.Excessive settlement.So the foundation must be safe against both the above failures and also it must be properly located. This proper orientation of a foundation can be well explained with the following example;
23 GENERAL REQUIERMENT FOR ANY DESIGN:- By design we always mean that what are the stresses acting on a particular member and the corresponding size of the members that theses stresses can be carried out efficiently. The general principle of the design is to design the structure into different elements. We are going to discus only one element, i.e. foundation.Designing is done in two stages;AnalysisSizing.
24 STRUCTURAL ANALYSIS:- In first step of every design, we analyze the state of stress and see the strain due to these stresses. In analysis we see the type of loading, type of strain and the modes of failure. In foundation design these stresses are called as bearing capacity and strains as settlements.So in foundation design, analysis means the determination of bearing capacity and settlement. We have various methods both field tests and empirical methods for finding bearing capacity and settlements.
25 SIZING:- Step # 01(Material Selection) Before going to sizing, we decide about the material to be used in the construction of the footing e.g. wood, concrete, steel etc. it depends upon the availability of the material and economy. The cost of project mainly depends on it.Since the foundation system is a very complex system, the construction material is not homogeneous. It consists of soil and other materials (wood, concrete etc.). here we will take concrete only.
26 SIZING:- Step # 02 (Dimensioning) Now using the data from analysis and the material selected the dimension are chosen (i.e. thickness, width, depth of pad) and the design is completed.Step # 03 (Documentation)Now the design is represented in the form of drawings and the construction specifications (i.e. procedure, problems and solutions) are also mentioned.
27 STRUCTURAL DESIGN:-In design that takes into account the technical aspects related to concrete is called as Structural Design.
28 GEOTECHNICAL DESIGN OF FOUNDATION:- For the geotechnical deign of the foundation the following steps are observed;The choice of foundation system between deep and shallow foundation.Fix the vertical location of the foundation i.e. Df in case of shallow and ‘L’ in case of pile foundation.Bearing capacity and settlement analysis and choose an appropriate value of the design pressure “qd”, bearing capacity equation and settlement equation.Using the information of (3) fix the dimensions in the plane i.e. ‘B’ & ‘L’.Evaluate the construction problems such as the problem of excavation, dewatering, water proofing and water tightening, deterioration of concrete and suggest their remedial measures.
29 STEPS OF GEO-TECHNICAL DESIGN Selection of the type of foundation system.Fix the vertical location i.e. Df of the foundation.Bearing Capacity and Settlement Analysis and from this a suitable value of “qd” i.e. the design pressure.The dimensions in plane (B & L)Construction Specification.
30 Physical Requirements:- Following are the different physical requirements;Footing should be belowTop organic soil.Susceptible zone.Surface erosion zone.Frost line.Scour depth.There should be the specified edge distance i.e.Level Difference
31 Step No. 1:-Selection of the foundation type:- For this the following steps are kept in mindType of structure and its requirementsSub soil profile at the site.Overall impact on the environment.Relative cost and construction facilities.Broadly speaking the types of foundation are;Shallow Foundations.Deep Foundations.Floating Foundations.
32 Step No. 2:- DEPTH OF FOUNDAION; For depth of foundation, the following two considerations are kept in mind,Mechanical Consideration.Physical Consideration.In mechanical consideration we check Bearing Capacity and Settlement.For Bearing Capacity Terzaghi’s equation (for general share failure) is applied i.e.qult = ScCNc + γ Df Nq + Sγ0.5γBNγFrom this equation it is clear that with the same soil, the properties remain the same and if ‘b’ is kept constant, then the Bearing Capacity goes on increasing by increasing the depth, but economy is also given due regards.
33 Step No. 3:- BEARING CAPACITY ANALYSIS:- FOR BEARING CAPACITY:-qult = CNc + γDfNq + 0.5γBNγqult / F.O.S = safe gross B.C or safe B.C(qult )Net = CNc+ γDf (Nq-1) + 0.5γBNγ(qult )Net / F.O.S = safe net B.CFor square footing and circular footing;qult = 1.3CNc + γDfNq + 0.5γBNγFor pure clayNc =5.7, Nq=1 & Nγ=0B.C calculated by these equations is called B.C w.r.t. shear.
66 Doors General Classifications Flush doors Panel doors Smooth on both sidesMahogany or birch plywoodPanel doorsHeavy frame around perimeterPartsStilesRailsPanelsLouversStiles – vertical membersRails – horizontal membersPanels – Thin material enclosed by stiles and rails
67 Exterior Doors Typical sizes Sloping sills to shed water 6’-8” tall by 1-3/4” thickEntry door minimum 3’-0”InsulatedSloping sills to shed water
68 Exterior Doors French doors Swinging doors Sliding doors Garage doors Mullions and muntins between glass panesOne large glass panesIndividual, pairs, groupsGarage doorsOverheadOne piece or sectionalWidthsSingles: 8’, 9’, 10’Doubles: 15’,16’, 18’Height generally 7’-0”Swinging doorsHingedSwing into the houseSliding doorsWood or metal framesTempered glassAccess to deck/patioCommon widths6’-0”8’-0”
69 Interior Doors Standard sizes Standard widths Height: 6’-8” Thickness: 1-3/8”Width: Varies based on 2” moduleStandard widthsEntry: 3’-0”Bedrooms: 2’-6”Baths: 2’-0” or 2’-4”Closets: As large as possible
70 Interior Doors Bi-fold Sliding/Bypass Set of two doors make up one unitHung on a trackPopular for closetsSliding/BypassUsed in wide openings
71 Interior Doors Pocket doors Double-action Hung on a track Slides into a wall cavityFrees floor spacePackaged with framed pocketDouble-actionSpring hinge mountedSwings two waysOne or two doors
72 Windows Purpose Admits light Provides fresh air and ventilation Adds detail, balance, interestVisually enlarges interior space
73 Window Types Double-hung Horizontal sliding/gliding Casement Two sashes slide up and downMost commonly usedHorizontal sliding/glidingTwo or more sashes slide horizontallyOperates on a trackCasementHinged sashes; outward swing
74 Window Types Awning Hopper Fixed Sash hinged on top; swings outward Allows open unit during rainHopperHinged sash on bottom; swings inwardAllows for unusual shapesFixedDo not openCombined with other windows
75 Window Types Bay and Bow Skylights Fixed or casement Project from structureBay windows offer traditional styleSides 450 or 300Depth between 18” and 24”Roof structureBow windows are in a circular patternSkylightsBuilt into roofAdmit light
76 Door/Window Schedules Marks placed on floor plan identify doors & windowsNumbers or letters inside circles or polygons identify individual unitsPlaced close to door & window symbolsSame mark used for doors/windows with same size and characteristics
78 Definition: Different parts of staircase: Construction designed to bridge a large vertical distance, by dividing it into smaller vertical distances called steps.Different parts of staircase:STEP--Tread-RiserBALUSTRADE--Baluster-Handrail-Newel Post
80 Guide lines for fixing the dimensions Rise (R) : 150mm to 180mmTread (T) : 220 mm to 250 mm- for residential buildings.Rise (R) : 120 to 150 mmTread (T) : 250 mm to 300 mm – for public buildings[T + 2R] : Between 500 mm to 650 mmThe width of the stair0.8 m to 1 m for residential building and1.8 m to 2 m for public building.
81 Guide lines for fixing the dimensions Contd… The width of the landing is equal to the width of stairs.The number of steps in each flight should not be greater than 12The pitch of the stair should not be more than 38 degrees.The head room measured vertically above any step or below the mid landing shall not be less than 2.1 m.The height of the balusters should be around 0.75 to 1 m.The space between two balusters should not be more than cm.
82 CLASSIFICATION Based on shape of plan: Stair Plans Straight staircase “U” staircase“C” StaircaseStair Plans
90 Stepsure Winder System Easier to negotiate than triangular winders Provides a spacious passing pointTuscan StaircaseCharacteristic to the Tuscan style are clean lines and strong visual elements such as steel balusters, cut stringers, with paint finishes that highlight clear-finished treads and continuous handrails.Tuscan stairs were often tiled over concrete.
91 Victorian StaircaseVictorian staircases have a solid architecture style, strong on decoration, with large newel posts, elaborate turnings, and complex tread bracket designs. Elaborate handrail contours and patterns, handrails were often larger (80mm * 60mm) and continuous. Timbers are deep in colour, or are stained to a rich dark finish.
94 Glass StaircasesThese are made by using stainless steel bars and brackets, and thick glass slabs as treads.
95 Disappearing StepsThey work by having the frame of the stairs slide out from the wall, powered by hydraulic pistons, and having the stair planks fold over the frame one at a time. When finished, the stair frame slides back in the wall and the planks stand straight up, flush against the wall.
96 Scala Constrain del Bovolo, Venice Spiral staircase used as facade
97 Staircase as a Sculpture by Olafur Eliasson, 2004, Munich, Germany.These staircase are not a structural but just an aesthetic element of design
99 After the foundations have been completed and the external walls constructed the construction of the floors commences.Floors construction
100 Function of a ground floor To carry loads imposed on them.To prevent dampness rising from the ground into the building.To provide a degree of thermal insulation.To prevent growth of vegetable matter in the building.To provide a suitable wearing surface.Basically there are two types of ground floors:-solid floors and suspended floors.
101 Solid ground floorOne in which the whole floor area is in contact with thesubsoil. Comprised of three main components:-Hardcore The purpose of this is(a) To ensure consistent material over the whole floor area.(b) To reduce capillary action of moisture from the ground because of voids within the hardcore layer.(c) To make up levels after removing topsoil and reduced level excavation.(d) to provide a clean dry and firm working surface. The top of the hardcore should be blinded with a fine dust or sand to fill the voids, prevent grout loss from concrete and protect D.P.M. if placed in this position.
102 Solid ground floorDamp proof membrane (DPM) An impervious layer to prevent moisture travelling through the floor to the inside of the building eg. polythene sheeting. Concrete bed This provides the solid level surface to which screeds and finishes can be applied.
103 Floor detail at junction with a cavity wall 1200 gauge polythene DPMSkirting50 mm min InsulationSand and Cement screedSand and Cement screedDPC 150mm minimum above Ground level100mm Concrete sub floorGround levelHardcore
104 Square edge flooring 150mm wide and 20mm thick. Timber floorsSupporting wallSuspended timber floor joists are supported by the walls which transfer the load from the floor, through the wall to the foundations.The traditional method of providing a flooring surface on top of these joist’s was sawn timber boards which had square edges. These boards were butted together and nailed down unto the top of the joist.The quality of the flooring boards was improved by the addition of tongue and grooved joints.Square edge flooring 150mm wide and 20mm thick.Floor joistSupporting wall
105 Timber ground floorsIf timber ground floors are used ventilation must be provided beneath the floor construction. The reason for this ventilation is to prevent the moisture content of the timber rising above an unacceptable level (i.e.. 20%) which would create the conditions for possible fungal attack.Sheet materials such as plywood and chipboard are now the most popular coverings to floor joists. The most common size of sheets are mm x 2440mm.Floor joists are usually placed at 400mm centres.Joist spaced at 400mm centres.Plywood sheetingPositions for ventilation
106 Suspended T beam concrete floor Pre-stressed concrete floor beams cast in the shape of an inverted TConcrete blocks laid between T beams100mm sand and cement screed on top of beam floorPre-stressed concretefloor beamsPre-stressed T beam concrete floors were one of the first methods of creating suspended concrete floors. The beams were set in position in such a way that a 450mm concrete block fitted neatly between the beams. The load of the floor was transferred to the foundations by the beams.
107 Suspended concrete floors HomeSPAN is the trade name for a suspended concrete flooring system which has recently been developed for the domestic market.This flooring system comprises of flat precast concrete planks generally 600mm wide and 150mm deep. It can carry domestic loadings up to 5m clear span.These concrete floors have excellent sound insulation and fire resistance.After settlement, cracking is dramatically reduced as most cracks results from the shrinkage of timber joist.Suspended concrete flooring slabs.Walls constructed to support floor slabs.