Site Analysis and Investigation

Site Analysis

• It involves surveying and studying the environment to determine its influence on the building's design, structure, and layout
• Site visits happen at the beginning of the design process
• A detailed site analysis needs to be done after the site visit to grasp all the features of the site
• Site analysis is critical for collecting statistics related to the site and its future design
• A poorly conducted site analysis results in poor design, because all accessible evidence is not available
• There is no such thing as too much site knowledge
• Important aspects to consider are location, topography, geology, soil types, slope stability and drainage

Site Investigation Steps

• Site investigation is the collection of information and appraisal of data
• It is the assessment and reporting of ground hazards beneath a site
• Performed to obtain physical properties of soil and rock around a site
• Used to design earthworks and foundations for structures and repair any distress to structures from subsurface conditions
• Purposes include evaluating site suitability, enable economic design and identify construction concerns
• Soil investigation provides important information, necessary to decide on foundation type, bearing capacity, settlement estimation, and solutions to environmental problems

Soil Exploration

• It provides several selections including alternative types or depth of foundation, methods of construction, safety of structures, and selection of construction materials
• Soil exploration should provide different layers of soil, thickness of soil layers, depth to bedrock, location of water level and groundwater issues, as well as any special concerns

Desk Study

• Work taken up before starting on site and the ground investigation
• Needs to be the first stage of site investigation
• Used to plan the ground investigation
• Focuses on researching the site to gain geological and historical knowledge
• Collection of available information, like site plan, structure type/size/importance, loading conditions, geotechnical reports and maps
• A Geographical Information System (GIS) integrates software, hardware, and digital data
• GIS is capable of capturing, managing, analyzing, and displaying spatial information for better visualization
• Google Earth can provide views of satellite Imagery, maps, terrain, and 3D structures of site

Location Topography and Geology

• The location is important to project owners to have their buildings seen from certain areas
• Location can impact available space, access, safety and surrounding environments
• Topography is considered for land planning
• A qualified land surveyor conducts topographical surveys
• The buildings placement, parking, and access points are affected when there is a lot of topography change in a site
• Flat terrain will provide easier constuctability compared to a site with steep slopes
• Geology is the structure, content, and stability of earth materials
• Depth to bedrock is crucial for surficial geology and construction

Site Reconnaissance

• The practice is normally done as a walk over survey of the site
• Information about the overall site layout, topography, and geology need to be collected
• Examination of local conditions such as the climate, stream flow, groundwater, and weather are needed
• Records and photographic records are taken if needed

Hydrogeology and Instability

• Evidence of hydrogeology issues includes wet marshy ground, springs, ponds, streams and wells
• Signs of instability includes bent trees, hummocks and displaced fences/drains

Ground Investigation

• The practice is done from the information collected from the walk over survey
• Soil investigations also use trial pits which are shallow excavations up to 6 m
• Trial pits are used for block sampling at the surface, and to detect the presence of utilities before any borehole excavation
• Boreholes help determine the nature of the ground (usually below 6m depth) and recover undisturbed samples for testing
• The more boreholes, the better possibility of correlation and more trustworthy the results

Soil Samples

• Soil samples are either undisturbed samples or disturbed samples
• Undisturbed samples represent soil conditions in-situ for structural properties testing, but aren't truly undisturbed
• Disturbed samples have altered natural structure, but retain physical and chemical properties without in-situ structure

Soil Exploration Report

• The report includes the purpose of the investigation and type of investigation
• The report should include description of the site's configuration, surface features, area geology and soil conditions
• Testing results, discussions, designs and construction are included
• Recommendations should be made for foundation type, depth, bearing pressure, and methods

Groundwork

• Typical groundwork consists of site clearance and preparation, excavation of foundation trenches, and groundwater control

Site Clearance

• Practices of clearing above ground requirements, such as trees, bushes, walls, and slabs are shown in site plans.
• Plans show the position of services so they can be cleared or avoided

Site Types

• Brownfield sites will need previous demolition and clearance of concrete slabs
• Greenfield sites will require soil removal

Contaminated Ground

• Due to brownfield sites and government policies, sites need to be decontaminated before building
• Contaminated soil needs to be removed and replaced with clean soil

Tree Protection

• Trees may have a preservation order from the local authority
• The trees are protected from displacement or removal
• Permissions are need from the local authority before removing any tree from the site

Waste Removal

• Waste needs to be taken to a license landfill on lorries or skips
• Inert waste like brick can be used as fill
• Rubbish cannot be burned at building sites

Brownfield Waste

• Cost effective to crush material to be used for hardcore if approved

Vegetable Soil

• Building regulations state land must be clear of vegetable and organic matter

Reduced Level Excavations

• Grading and leveling is completed from cutting, filling or a mix
• The cut method is the process of high ground removal and has a solid base
• Soping sites can be used from the cut the fill methods which requires compaction in layers

Setting Out

• Physical positions of corners and walls of a building are developed
• Dimensions are transferred from the layout plan to the ground
• Excavation outlines and wall center lines are defined
• It has to be done when building a new house or when renovating an old building
• A contractor oversees, with project managers like engineers and architects
• Determines the position of corners, rooms, and wall trenches

Removal of Topsoil

• After topsoil has been removed the foundations can be set up
• Hydrated lime can be used to highlight the line of foundations
• Specific trench widths are available for the digger buckets

Datum Level

• A datum level provides reference and measurements for other quantities
• Establish a site datum where no benchmarks are present
• Markers can be set in concrete or plinths

Setting Out Importance

• Site features must be drawn to the correct position and level
• Setting out extracts pegs, profiles, and other marks information construction drawings

Boundary

• The boundary line defines the perimeter of the lot and establishes it's legal ownership

Verge

• The verge is the area of land between the street and boundary and is owned by the local council
• Services that are contained are electricity, water, gas, telephone, footpaths, sewers and stormwater drains

Setting Out Principles

• Three main principles are horizontal, vertical positioning techniques.
• Position points give the location of the details of any building

Horizontal Control

• It's important to protect all points
• Wooden pegs can be used for non-permanent markers
• Concrete marks can be used as permanent markers
• Horizontal control points can be baselines, reference grids or offset pegs

Horizontal Control Explained

• Baselines or grids are used to establish design points
• Corner pegs will be lost during excavations
• Offset pegs are used to avoid any extra pegs being lost

Vertical Control

• Temporary Benchmarks must be fixed during reconnaissance, so they can be allowed to settle before leveling
• 20mm steel bolts of 100mm length, can be used in ledges, footpaths and steps are ideal

Vertical Control Explained

• Horizontal timber cross pieces are attached to a single upright, or pair of uprights in the ground
• The upper edge is set to a suitable hight and alignment
• Profiles are set at 2 or 3m, at right angles so not to damage them

Process of Setting Out

• Two square offset liens and set from the kerb in step 1
• Fix a ranging Line to there set positions
• Corners pegs will be placed to give drawing positions of the drawing which relates to the site in step 2
• Establish first point on Line and then measure width
• Adjust Square carefully to cross the frontage 90 and set out in step 3

Right Angle Triangle

• Fix the nail exact from the right corn, set the corner pef in step 4
• Put a nail on Corner peg a on first line. Tape 4M on the corner peg and set tape too other
• Set to correct reading once correct line 90 to reference point.

Setting Out - Step 5 &6

• Connect to front of the back line
• Angle should start 90
• Setting should be confirmed where measure, adjust back to their correct settings

Setting Up - Step 7

• Enables connect easy to be checked for each stage, if needed
• Extended by holding line for each step, on side wall

Setting Corner Profile

• Distanced well away for added work
• Positioning the well with equal spacing to assist with each location

Position of Foundations

• Using line, and corner point you can easily paint foundation locations
• Lime added if needed

Trenches

• Set in Profile Boards
• Using clear side to remove line
• Allows for easy placing along marked sections.