Technology Studies Flashcards
Mast Climbers (6)
Reduced Access Time Single 5000kg Double 10,000kg Increased Capacity Improved Safety Reduced Damage Risk to Components Reduces fixing period by 40%
Scaffolds
Useful for lightweight panels in not high rise projects
Tower / Mobile Cranes
Can be slow and expensive
Influence on choice of panels (5)
Size and Weight Method of fixing Fixing plant requirements Access to the building Scaffold or fixing from internal floors
Beam and Block Floor (5)
Also known as Beam and Pot Wide range of block available : Beam + Polystyrene / Precast and Infill block Depth of prestressed varies 100-200mm Depends on span/loading
Metal Deck Floor (7)
Metal deck shot fired to supporting steelwork Lat stability
Shear bolts fitted to tie to main frame
Fabric reinforced / topping (concrete)
On site floor construction
Design varies sizes / shape / finishes
Various thickness depends span between beams
Incorporated into multi-storey steel framed buildings
Precast Concrete Floor (3)
Wide range of hollow and shallow designs
Depth varies 600-1200mm
Requires heavy plant for lifting
Precast Plank Floor (6)
Permanent replace to a formwork soffit suspended floor 50-100mm thick High quality due to factory production Design flexibility Fire and sound resistant Speed of erection
In-situ Concrete Framing Advantages (4)
Flexible Design
Strong monolith
Everything produced on site
Simple construction method
In-situ Concrete Framing Disadvantages (4)
Difficult to change
Errors are expensive to fix
Quality checks require
Labour intensive
Precast Concrete Frames (5)
Relatively fast to build High quality due to prefab Less labour on site Requires heavy lifting plant Logistical Difficulties
Steel Frames (6)
Completely built off site Complex structures trial erected Easy to Assemble Less labour on site Logistical difficulties Requires additional fire protection
Commercial Structural Considerations (4)
Time of Construction
Practical Design
Floor Area
Possible Changes
Residential Structural Considerations (4)
Quality
Insulation
Protection - Security and Fire
Durability
Portal Frames (5)
Use of continues or rigid frame allows for extra space
Wide Spans 60m+
Prefab components fast construction
Stress/frame deflectio taken pin/pockete (deep foundat)
Can have future expansions
Materials for Portal Frames (4)
Precast Concrete
Steel
Lattice Steel
Wood and Glulam
Diaphragm Walls (5)
Excavating a trench before main excavation
Bentonite used to stabilise excavation
Prefab reinforcement is lowered
Concrete pumped replacing reusable bentonite
Contiguous Bored Piling (5)
Bored in-site piles with grout between them Placed as near to each other as possible CFA or Rotatory Bored Piles can be used Alone not waterproof grout is needed Can incorporate ground anchors
Secant Piling (Stent Walls) (4)
Excav / Formwork / Concrete guide walls / remove form
Insert :
PFA Piles / Reinf concrete piles creates continuous wall
Break Guide walls
Insert capping beam
Ground Water Permanent Methods (8)
Sheet steel piling Ground Anchors H Piles Infill Panels Secant Piles Diaphragm Walls Continous Piles Cement and Chemical Grounding
Ground Water Temporary Methods (7)
De-Watering Well-Pointing Use of Pumps Ground Freezing Temporary Sheet Piling Bitumen Grout Electro-Osmosis
Concrete Handling Techniques (3)
Cranes / Skips
Small and Medium Pours
Site Mixed / Site Batching Plant / Ready Mix
Requires Crane and Various Skip Types
Concrete Handling Techniques (6)
Pumping
400-700 quid a day to hire
Cost / Time effective for large quantities
Cheap for small pours too
Requires careful logistical planning
Labour intensive - levelling and finishing
Requires pumping equipment
Piling Techniques (3)
Displacement
Replacement
Vibro-Replacement
Replacement Piles Types (2)
Percussion Bored - Small and Medium sized project
Rotary Bored - Any Project
Site Layout Planning (5)
Security / Fencing / Entrance Gates Location of offices / accommodation / other site service Welfare facilities Traffic Movement Plan Storage of Plant and Materials
Traffic Movement Plan (4)
Temporary Roads
Movement Corridors
Hardstandings
Access Points
Site Types - Open Field (6)
Housing estates / factory development Easy Access A lot of space to use - storage Allows for most efficient and effective construction May be far away from roads Requires new local infrastructure
Site Types - Long and Thin (5)
Restricted Width Complicated movement corridor on site Logistical Difficulties Allows for limited construction methods May cause problems and additional cost
Site Types - Restricted (7)
Tight site in cities / industrial improvement works
Occupies whole footprint / high % of site
Restricted access / care in planning required
Complex storage and equipment arrangements
Complex logistical arrangements
Potential difficulties with crane / surrounding parties
Often required basement construction
Advantages of Prefab Construction (10)
Value for Money Standardisation Minimal Wastage Minimal Defects Better Quality Control Minimal Environmental Impact Greater efficiency and productivity Increase in predictability More rapid on-site construction BIM can be used
Disadvantages of Prefab Construction (4)
Need for Fabrication sites
Increased cost of late changes
New methods of construction
Limited tolerance
Demolition Disadvantages (4)
Dangerous
Requires a lot of planning and Preparation
Requires heavy plant
Labour intensive
Methods of Demolition (5)
Human operatives (small projects) Collapse Pulling / Pushing Wrecking Ball Implosion (Technical Explosion)
Buildability Definition
The extent to which the design of the building facilitates ease of construction, subject to the overall requirements of the finished building
Buildability Factors of Influence (4)
Design
Technical requirements
Resource requirements
Future of project
Three Types of Basement Construction (3)
In-Situ Concrete Basement
Traditional Brick Basement
Pre-cast Concrete Basement
In-Situ Concrete Basement (4)
Construct Floor Slab
Construct Walls / Reinforcement / Formwork / Concrete
Construct Roof Slab in-situ or precast
Water bar may be included in walls/joints (sealing)
Traditional Brick Basement Construction (8)
Construct Floor Slab Asphalt Floor Surface Construct Inner Brick Wall Asphalt Wall Protective Brickwork Skin Construct Inner Floor Construct Roof Slab Require waterproofing in asphalt form
Precast Concrete Basements (4)
Construct Floor slab / Reinforce / Formwork / Concrete
Erect Precast Walls
Construct Roof Slab precast or In-Situ
Single wall / double wall / infill with concrete
Water going to be a problem Basements
Excavation over a large area
Steel Sheet Piling is required
Single face support the only option
Ground Anchors (3)
Permission needed under public land (trespass)
Authorities impose conditions (not allow 2m near sewer)
Adjoining neighbours issue, reject alternatives needed
Diaphragm Wall Disadvantages (3)
Specialist technique
Personnel Required
Expensive
Sheet Pile H Pile (3)
Provides cut-off to ground water entry
Placed Vertically around the excavation
Concrete slabs connected in between
Act as permanent supp and surface for basement wall
Pile Foundations Definition / Fact (3)
Transfer the load of the structure to the bearing ground.
The main components are the pile and the piling cap
Main materials for the pile is steel, wood and concrete
Four Types of Piling
Displacement - Precast Driven
Replacement - CFA used 4 storey steel framed building
Vib-rep - Impro weak soil bearing cap w/ stone column
Mini-Piling System - Used for Life Shaft Base
End Bearing
Friction
Load carried through weak onto firm strata
Load transfered into surrounding soil by friction of pile
Vibro-Replacement Wet / Dry Technique
Water jetting forming hole prior to stone being placed
Vibrator to form hole then fed with dry stone
Three Types of Concrete Frame
Column and Beam Frames
Flat Slab Construction
Crosswall Construction
Advantages of In-Situ Concrete (5)
Amenable to almost any shape Connections homogenous to rest of structure Resistant to disaster Whole production on site Design can proceed with construction
Disadvantages of In-Situ Concrete (3)
Subsequent alterations very difficult
Errors in setting out formwork
Reinf / formwork Labour intensive / On site plant
Column and Beam Frame (2)
Have downstand beams
Integral part of construction
Formwork
The process of creating a mould for which concrete is poured in
Shuttering
Most popular type of formwork
Timber / plywood must be waterproof
Formwork Considerations (5)
Type of concrete and temperature
Need to resist the dead load of wet and dry concrete
High quality workmanship and checking required
Retain its shaped, propped vertically/horizontally
Materials should be appropriate for reuse
Portal Frame Building Examples (3)
Warehouses
Factories
Leisure Centres
Rigid Portal Frame (4)
Rigid Joint at Base
Rigid Joint to connect haunch/roof
Haunch may be incorporated
Apex Joint
Steel Portal Frame Cladding / Bracing
Vertical columns introdu at gables to support cladding
Wall / roof bracing req at selected bays end of building
Portal Frame Profile Examples (4)
Skylight
Asymmetrical
Symmetrical
Curved Rafter
Lattice Portal Frame (4)
Open grid of steel angles or tubular members
Pinned joints at apex or stanchion
1/2/3 pin joints available
Pin joint supports stanchion reduces bending moment
Lattice Portal Frame Requirements (3)
Adequate wind and side bracing
Portals are normally spaced at 6m centres
Variety of roof/wall claddings are available
Fixing Small Panels (3)
Mast Climber
Scaffold
Hydraulic Platforms (Scissor Lift)
Panel Examples
Scissor Lift
Mast Climber
Lightweight Aluminium Panels fixed onto the face
Brickwork Panels
Storey Height Panels (2)
Heavy cladding panels held in position by steel plates and connectors fitted to the ends of floors or onto the wall face of the building
Glass storey hei panels, crane w/ mast climb fixing gang
Internal Fitting Storey Height Panel (3)
Mini hydraulic floor crane
Panel lifted from trolley from floor below
Panel lowered into position and fitted to bracket slots
Cantilever Boxes (2)
Fixed between floors of a building
Loading materials to be fitted
Structural Insulated Panels (5)
Rapid erection for domestic and commercial use Ideal backing for overfixing rainscreen Made from Orientated Strand Board Used for floor/roof/wall of a building Continuity of insulation and air leakage
Benefits of SIPs (7)
Environmentally friendly Speed of insulation Strong and lightweight Factory produces (defects/quality) Minimal waste/max recycling High insulation values Extern finishes render, rainscreen, weatherboardd, bricks
Rainscreen (3)
Allows for the deflection of most of the rain
Gap between to allow air movement
Space prevents water from penetrating the wall
Curtain Wall Definition / Idea
A wall surrounding a building but doesn’t support roof.
Only support own weight/weight imposed upon them
Typical Curtain Wall composed of
A lightweight aluminium frame
Glass / opaque panels can be fixed
Stick Systems (2)
Installed piece by piece
Glazing inserted into frame from out/inside dep access
Unitised Systems (3)
Prefab off site and delivered in panels
Factory produced quality / defects
Low installation time
Pre-Contract Stage (3)
Site Layout Planning
Construction Methods
Safety Procedures
Contractors Pre-Contract Meeting (3)
Announce award of contract
Distribute tender analysis data to QS
Propose/appoint contractor site management team
Site Hazard Board
Site Layout Proposal
Located adjacent to site mess / office facilities
Approved by PM / Client
Site Layout Plan Major Plant / Sub Contract / Vehicles (4)
Siting of major plant
Locat/radius tower crane - site access roads / storage
Separate storage for sub contractor materials
Vehicle Parking - parking elsewhere causes disputes
Welfare Facilities (3)
Drying facilities
Signing in
Toilets
Site Security (4)
Site fencing / hoarding
Secure entry gates
24 hour video security
Other Site Considerations
Sign
Pedestrians
Access areas
- Pedestrian access routes to work areas
- Space around building for the provision of scaffolding, hoists and access areas to the base of hoists
- Site signage – directory, safety and warnings
Advantages of Precast Concrete Structures (5)
Manufacture off site Speeds up erection time Quality assurance Reduced onsite labour Doesn't require formwork
Disadvantages of Precast Concrete Structures (5)
Design complete before build Last minute alteration impossible More expensive Care in handling / protection Damage to elements delay construction
Steel Frame Disadvantages (3)
Inaccuracies in manufacture
Fire proofing needed
Safe working conditions during erection difficult
Faster Buildings (4)
Simple forms
Few technical activities
Readily replaceable resources
Extensive and similar workplaces
Slower Buildings (4)
Complex
Many technical activities / Different activities
Unique resources
Many small and differing workplaces
Construction Material Waste (4)
Design Waste - Cutting to fit
Take-off/Specifi Waste - Excessive materials delivered
Delivery Waste - Incorrect specification
Site Waste - Poor storage
Cladding Requirements (5)
Self supporting between framing members Provide rain resistance Resist positive/negative wind pressure Thermal / sound insulation Fire resistance
Plant Selection Determined (10)
Workloads for handling Range of weights / packaging Work carried out and outputs required Access between unloading / point of fixing Character of site and boundaries Pollution Sequence of events Temporary roads Time of year Obstructions above / below ground
Geography of the site (9)
Geological conditions - clay, rock, sand, flint, gravel
Natural drainage of site
Slope characteristics - gentle / steep / plant impact
Access to site
Overhead - power lines / preserved trees
Below - gas/water/electric / existing drainage
Offloading
Plant over swing
Noise limitations
Large / Small Displacement Pile
Solid pile - timber / concrete
Rolled steel like H-pile
Replacement Pile (3)
Boring / other methods of excavation
Bore hole lined with casing / tube
Left in place or extracted after use
Pile Classification (3)
Large Displacement
Small Displacement
Replacement
CFA Piles
Vibration free
Reduced noise
Soft water bearing ground
