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Design methodology - Coggle Diagram

- - - - Precast concrete
        
        With in-situ topping
        
        Topping provides diaphragm action (transferring lateral loads to stability system)
        
        Without in-situ topping
        
        Cores broken out at supports
        
        Reinforcement placed in cores to attach to shear studs
        
        Beams act non compsitely during construction
        
        Subject to weight of wet concrete and imposed construction load (typ. 1.5 kN/m2)
      - Steel and in-situ concrete
        
        Different profiles
        
        Trapeziodal (e.g. Comflor 60 or 80 from Tata Steel)
        
        Dovetail (e.g. Comflor 51+ from Tata Steel)
        
        Deep Profile (e.g. Comflor 210 or 225 from Tata Steel)
        
        Spans between secondary steel beams
        
        Requires propping during concrete curing time
        
        Standard (dovetail or trapeziodal) decking, spans 2.5-3.75m without props
        
        Deep decking, spans 4.5-7.5 without props
        
        In-situ concrete, typ. 130-150mm thick
    - - Precast concrete
        
        Typically 1.2m wide
        
        Therefore bay sizing would want to be intervals of 1.2m?
        
        Typical spans 6m (150mm thick) to 9m (250mm thick)
        
        Span directly onto primary beams
        
        Use in-situ topping to provide diaphragm action
        
        Typically 50-75mm thick
      - Timber
        
        Often supported on steel beams, but can use engineered timber joists (e.g. timber I-sections)
  - - - Super imposed dead loads
        
        Heavy partitions
        
        Lightweight partitions
        
        Plant?
    - - Residential
      - Office
      - Commerical
      - Warehouse/storage
      - Construction, typ. 1.5 kN/m2
- - - - Span, typ. 6-9m, max. 15m
      - Depth, span/20 for floor, span/25 for roof
  - - - Spacing, typically between 2.4 and 3.0m, but can go up to 4.5m
      - Span, typ. up to 16m (12m from IStructE)
      - Depth, span/25 for both floor and roof
  - - - Cantilevers, length/180
      - Carrying brittle finishes, span/360
      - Other beams, span/200
- - - - Applied stress <= allowable stress
        
        Applied stress = stress due to working (unfactored loads)
        
        Allowable stress = failure stress / global factor of safety
      - Types
        
        Shallow foundations
        
        Allowable bearing pressure
        
        Dry non-cohesive (sands / gravels):
        q_all = 7 or 10 × N, for strip or pad footings, respectively
        
        Typical N values 0-50 (CBSDM, Table 3.47)
        
        Saturated non-cohesive (at or below water table): q_all_wt = q_all / 2
        
        Where: N = Standard penetration test (SPT) value
        
        Cohesive (clays):
        q_all = 2 × c_u,
        
        Where: c_u = undrained shear strength
        
        Typical c_u valyes vary between 20-150 kN/m2 (CBSDM, Table 3.41)
        
        Sizing
        
        Pad / strip footings
        
        Mass concrete
        
        Depth >= 300 mm, <= 3000mm
        
        Ratios of projection (of footing from column face) to depth (of footing), dependent on concrete grade and allowable bearing pressure (IStructE Design Manual to EC2, 5.10.5.1)
        
        Reinforced concrete
        
        Similar depth/projection ratios (IStructE DM to EC2, 5.10.5.2)
        
        Depth = effective depth + bar diameter/2 + cover <= 3000mm
        Effective depth (depth from upper face to rebar centreline) >= 300mm.
        Cover = typ. 75 mm
        
        Check shear at column perimeter does not exceed: v_Ed = V_Ed / (u_c × d) <= 0.2(1 – f_ck/250)f_ck
        
        2 more items...
        
        Raft
        
        If raft is sufficiently rigid, pressure can be distributed over entire area; however, a large raft is unlikely to be sufficiently rigid
        
        For less rigid rafts, applied bearing pressure = column load / raft area of column, q = W_col / (L_col × B_col)
        
        Where:
        L_col = column spacing in one orthogonal direction; and,
        B_col = column spacing in other orthogonal direction.
        
        Pressure distribution in a flexible raft is complicated; dependent on column spacing, soil stiffness and rigidity of the raft
        
        2 more items...
        
        Deep foundations
        
        Piles
        
        Allowable capacity
        
        Cohesive (clays):
        Q_all = Q_s / gamma_s + Q_b / gamma_b
        
        Where:
        Q_s = shaft capacity = alpha × c_u_s × A_s
        Q_b = base capacity = c_u_b × N_c × A_b
        gamma_s = factor of safety on shaft capacity = 3.0
        gamma_b = factor of safety on base capacity = 2.5
        
        4 more items...
        
        Non-cohesive:
        Q_all = (Q_s + Q_b) / gamma_fos
        
        Where:
        Q_s = shaft capacity = sigma_dash_v_av × A_s × k_s × tan(delta)
        Q_b = base capacity = N_q × A_b × sigma_dash_v_b
        gamma_fos = factor of safety = 3.0
        
        3 more items...
        
        Rock:
        Q_all = min{ Q_b / gamma_fos ; 0.25 f_cu A_pile}
        
        Obtain Q_b / gamma_fos from CBSDM, Table 3.49
        
        Sizing
        
        Standard bored pile diameters
        
        450 to 1800mm, in increments of 150mm
        1800 to 3000mm in increments of 300mm
        
        Spacing
        
        Pile spacing >= 3 × pile diameter, centreline to centreline
        
        Pile caps
        
        +/- 75mm tolerance on plan, therefore pile caps should 150mm beyond edge of piles to allow tolerance + 75mm cover
        
        Typ. pile cap thickness = pile spacing / 2 = 1.5 × pile diameter
    - - Design load effect / design load resistance <= 1.0
        
        Design load effect = characteristic load effect × load factor
        
        Design load resistance = characteristic resistance / material factor
  - - - Strip/trench footings
      - Rafts
        
        Reinforced concrete
      - Pad footings
        
        Mass concrete
    - - Piles
        
        Driven precast concrete piles
        
        Driven steel piles
        
        Rotary bored piles
        
        Continuous flight auger (CFA) piles
        
        Mini piles
      - Piled rafts
    - - Transfer load directly into ground
- - - - Balcony
        
        in a single family dwelling
        
        A5
        
        in hostels, guest houses and residential clubs
        
        A6
        
        in hotels and motels
        
        A7
      - Communal areas (including kitchens)
        
        in a single family dwelling
        
        A1
        
        in blocks of flats
        
        With three or fewer floors and four or fewer dwellings per floor per staircase?
        
        Yes
        
        A5
        
        No
        
        A6
      - Bedrooms
        
        in self-contained dwelling unit
        
        A1
        
        in hotels or motels
        
        A3
        
        other
        
        A2
    - - Wards
        
        A3
    - - Toilet areas
        
        A3
      - Areas with tables
        
        Generic
        
        C1
        
        Public, institutional and communal dining rooms and lounges, cafes and restaurants
        
        C11
        
        Reading rooms
        
        Without book storage
        
        C12
        
        With book storage (e.g. libraries)
        
        E12
        
        Classrooms
        
        C13
      - Areas with fixed seats
        
        Generic
        
        C2
        
        Assembly areas with fixed seating
        
        C21
        
        Places of worship
        
        C22
      - Areas without obstacles for moving people
        
        Generic
        
        C3
        
        Corridors
        
        In hotels, motels or blocks of flats (> 3 floors), or subject to crowds or wheeled vehicles?
        
        No
        
        C31
        
        Yes
        
        Subject to crowds
        
        C33
        
        Subject to wheeled vehicles
        
        C34
        
        Stairs and landings
        
        In hotels, motels or blocks of flats (> 3 floors), or subject to crowds?
        
        Yes
        
        C35
        
        No
        
        C32
        
        Walkways
        
        Light duty (i.e. accessible for one person)
        
        C36
        
        General duty (i.e. regular two-way pedestrian traffic)
        
        C37
        
        Heavy duty (i.e. high density pedestrain traffic, including escape routes)
        
        C38
      - Areas with possible physical activites
        
        Generic
        
        C4
        
        Dance halls, gymnasia or stages
        
        C41
        
        Drill halls
        
        C42
      - Areas susceptible to large crowds
        
        Generic
        
        C5
        
        Without fixed seating (e.g. concert halls, bars, places of worship)
        
        C51
        
        Stages in public assembly areas
        
        C52
    - - Billiard/snooker rooms
        
        A4
      - Museums or art galleries
        
        C39
    - - At or below ground level?
        
        Yes
        
        B2
        
        No
        
        B1
    - - Generic
        
        D1
      - Department store
        
        D2
    - - Generic
        
        E13
      - Generic static equipment
        
        E11
      - File rooms
        
        E14
      - Stack rooms (books)
        
        E15
      - Paper storage for priting plants and stationary stores
        
        E16
      - Dense mobile stacking (books)
        
        on mobile trollies, in public and institutional buildings
        
        E17
        
        on mobile trucks, in warehouses
        
        E18
      - Cold storage
        
        E19
    - - See PD 6688
  - - - Floor finish (75mm screed)
        
        1.8kN/m2 on plan
      - Ceiling and service load
        
        0.5kN/m2 on plan
      - Partitions
        
        Movable partitions
        
        Self-weight <= 2kN/m
        
        0.8kN/m2 on plan
        
        Self-weight <= 3kN/m
        
        1.2kN/m2 on plan
        
        1.0 kN/m2 on plan allowance (IStructE, Conceptual design of buildings, 2021, p.152)
        
        "However, this should be treated as a variable load, rather than a permanent one"
        
        "Loads due to movable partitions shall be treated as imposed loads" (BS EN 1991-1-1, 5.1(5))
        
        Also, from BS EN 1991-1-1, 6.3.1.2(8): Self-weight <= 1.0 kN/m
        
        0.5 kN/m2 on plan
        
        Blockwork partitions
        
        2.5kN/m2 on plan
        
        2.5kN/m2 on plan is typical industry practice, howver Brooker recommends an allowance of 3.0kN/m2 (IStructE, Conceptual design of buildings, 2021, p.152)
      - External walling
        
        Curtain walling and glazing
        
        0.5kN/m2 on elevation
        
        Cavity walls (lightweight block/brick)
        
        3.5-5.5kN/m2 on elevation
    - - “For steel buildings an allowance is often made on plan area for the weight of steelwork – typically 0.5 kN/m2 at floor levels” (IStructE, Conceptual design of buildings, 2021, p.152)