AAA551 Construction Technology III – Comprehensive Revision Notes

Course & Assessment Essentials

Code & Title: AAA551 / Construction Technology III
Credit & Delivery: $3$ contact hours/week over $14$ weeks (Semester 4)
Total Student Workload: $52$ lecture hours + $68$ preparation $=120$ hrs
Continuous Assessment:
- Assignment 1 – Group
- Assignment 2 – Individual
Core Learning Outcomes (CLO)
1. Illustrate RC construction requirements for small–medium scale projects
2. Reproduce construction methods for RC structures
3. Apply RC‐frame principles in design proposals

SUB-STRUCTURE

Soil Investigation (SI)

Purposes

Visualise soil profile; obtain undisturbed/disturbed samples for lab tests
Judge site suitability & advise on alternative sites
Supply input for economic, safe design (incl. temporary works)
Plan construction method & mitigate delay risks
Predict ground changes (natural or man-made) & environmental impact

Standard Sequence

Desk Study – collect maps, topo, ownership, utilities, previous reports
Site Reconnaissance / Exploration – climate, groundwater, existing cracks, cavities
Detailed Exploration – pits, borings, probes; long-term GW monitoring
Laboratory / In-situ Testing – classification, $k$ , shear, compressibility, chemical
Reporting – soil stratigraphy, bearing capacity, hazards, recommendations

Soil Basics

Texture Triangle: clay–silt–sand percentages
Coarse (non-cohesive) vs. fine (cohesive) behaviour: strength, permeability, plasticity
Weathered materials hierarchy: boulder → cobble → gravel → sand → silt → clay
Engineering keywords:
- Strength = internal friction + cohesion
- Compressibility – volume change under load
- Permeability – ability to drain

Field Techniques & Depth Ranges

Method	Typical Depth	Comments
Trial pit (hand/backhoe/excavator)	< $6$ m	Visual, block samples
Mackintosh probe	< $1.2$ m	SPT-like resistance
Hand auger	< $5$ m	Soft soils; disturbed sample
Boreholes (wash, rotary)	< $100$ m	Continuous core; in-situ tests

Foundations

Need for Variation

$\text{Foundation selection} \rightarrow f(\text{soil strength},\;W_{tot},\;load\ distribution,\; topography)$

Shallow Systems (depth < $2$ m)

Pad – isolated columns; common for non-load-bearing walls
Strip – linear footings; economical on slopes (uniform load spread; $450$ mm practical depth)
Raft / Mat – covers entire footprint; for soft clays, fills, or differential settlement risks
- Solid slab
- Beam & Slab raft (down-stand or up-stand beams)
- Cellular / Box raft – two-way beams & walls forming cells (usable voids, services)

Deep Systems

When upper soil is unsuitable due to: low $q_{allow}$ , high water table, compressible clays, heavy point loads.

End-bearing Pile – transfers load to hard stratum
Friction / Floating Pile – relies on shaft adhesion
Common materials: steel (H, box, pipe; coat vs. corrosion), precast RC (cased/uncased), timber (light load, rot risk), composite (steel + concrete)
Typical diameter < $600$ mm; length up to >30 m

Construction Aids

Blinding – $50$ – $75$ mm lean concrete or sand for clean base
Kicker/Stump – small upstand ensuring column alignment
Starter Bars – lapped rebars protruding into next pour

Settlement Principles

On cohesive soils: place heavier columns centrally; on non-cohesive (sand): heavy loads near edges to even settlement
Causes: structural weight, moisture changes, mining subsidence, ground movements

Retaining Walls & Earth Pressures

Resist lateral earth + hydrostatic pressures
Failure signs: leaning, bulging, cracking; triggers – poor drainage, shallow footing, overload
Wall Categories:
1. Gravity (mass concrete/stone; $h_{econ}\le1.8$ m)
2. Cantilever RC (inverted T/L; $h=1.2$ – $6$ m; heel/toe choices)
3. Sheet Piling (steel/wood; ⅔ embedment; tie-backs for tall cuts)
4. Anchored (tie-back cables/rods, drilled & grouted)
5. Counterfort/Buttressed variations
Design checks:
$\text{FS}<em>{slide}\ge1.5,\;\text{FS}</em>{overturn}\ge2.0,\;\sigma<em>{soil}\le \sigma</em>{allow}$
Drainage: weepholes $\approx100$ mm Ø @ uniform spacing; granular filter or geotextile; perforated footing drains

Waterproofing & Basements

Leakage paths: basement walls, foundation drains, household plumbing
Systems:
1. Monolithic Concrete (dense RC + joints + PVC water-bar; may need vapour control)
2. Drained Cavity (inner leaf + void + sump pumps)
3. Membranes
- Internal tanking (negative side) – easy retrofit, structure unprotected
- External tanking (positive side) – protects structure; bitumen sheets, PVC, polymer paints
Sheet Materials: Bituminous asphalt, rubberised asphalt, PVC, HDPE, water-based mastic, bentonite-HDPE composites

SUPER-STRUCTURE

Reinforced Concrete (RC) Frames

Structural hierarchy: foundations → columns → beams → floors → roof → walls
Frames provide clear spans, fire resistance, and integration with services

Columns & Beams

Column – vertical compression member; failure causes global collapse
- Classified by: shape, slenderness ( $\lambda$ ), load type, lateral ties
- Types: tied, spiral, composite
- Failure: crushing, combined stress, buckling (long‐slender)
Beam – horizontal flexural member
- Main (to columns) vs. Secondary (to main) vs. Tie vs. Edge

Floor Systems

System	Span Direction	Typical Span	Key Notes
Conventional slab + beams	One-way / Two-way	$3$ – $9$ m	Deep beams may remove internal columns
Flat Plate	Directly on columns	$\le5.5$ m (light); $t_{slab}=150$ – $200$ mm	No beams; low storey height
Flat Slab (with drop & column head)	Two-way	$6$ – $7.5$ m; $t=225$ – $300$ mm	Suited to warehouses; mushroom head
Waffle (ribbed two-way)	Two-way	>8 m	Aesthetic coffers; lighter dead load
Ribbed (one-way tee)	One-way	up to $9$ m (≈ $30$ ft)	Proprietary steel moulds; service voids

Walls

Masonry

Brick or concrete block + mortar; durable, fire-resistant, compression efficient

Party Wall

Shared wall between separate ownerships; $200$ mm solid or two $100$ mm skins; height $225$ mm above roof as per fire code

Precast Wall

Factory-cast panels; high quality, speed, reduced site labour; forms re-used >100 times

Reinforcements

Exmet expanded metal every 4th joint; controls cracks
Hoop iron / steel flats every 6th course; two strips per header

Lintels & Stiffeners

Lintel spans opening, transfers load to jambs
Stiffeners (columns/beams/lintels) at $2500\times2500$ mm grid when wall >3.5 m tall

Roofing (Flat RC)

Functions: exclude weather, insulation, structural safety
Flat RC roofs integrated with floor construction; allow recreational or parking use
Advantages: flexible planning, reduced building height
Disadvantages: waterproofing critical; ponding risk; longer programme; gutters & RWDP essential

UNIFORM BUILDING BY-LAWS (UBBL 1984, latest 2022)

Scope & Parts

Preliminary
Demolition
Plan Submission
Space, Light, Ventilation
Structural
Constructional
Fire Safety Installations
Fire Alarm & Extinguishment
Miscellaneous + 11 Schedules (loads, travel distance, fire resistance, staircase landing, etc.)

Key Structural Clauses

By-law 70 Parapets/Balustrades – design per $\text{MS EN 1991-1-1}$
71 Vehicle barriers – impact design
73 Foundations – comply with $\text{MS EN 1997}$ ; SI supervised by PE geotechnical
79 Party wall foundation not to cross lot boundary

Constructional Highlights

Party walls ≥ $200$ mm solid masonry; STC $\ge50$
Coping & projections via impervious material
Boundary walls: solid $\le1.8$ m; open $\le2.75$ m

Staircase-Related By-laws

106 Rise $\le$ $180$ mm; Tread $\ge$ $275$ mm; uniform
107 Handrails: at least one; two if width >1100 mm; height $825$ – $900$ mm
108 Flights: landings every $\le4.25$ m rise; max $16$ risers
168 Every upper floor needs ≥2 separate staircases except as allowed; stair width adequate for occupant load (Seventh Schedule)
140 Fire appliance access road: width $6$ m, loading $30$ t, clearance $4.5$ m

STAIRCASES & RAMPS (Chap 6)

Terminology

Tread, Riser, Nosing, Flight, Landing, Pitch, Soffit, Baluster, Balustrade, Headroom ( $\ge2000$ mm typical)
Going = horizontal distance; Line of Nosing = inclination reference

Dimensional Rules (common practice + UBBL)

Residential: Riser $150$ mm, Tread $255$ mm
Exit stairs: $\text{R}\le180\text{ mm},\;\text{T}\ge255\text{ mm}$
Max $16$ risers/flight; landing depth $\ge$ stair width (≥ $1100$ mm domestic; $1800$ mm straight exit)
Formula check: $2\text{R}+\text{T}=600\text{ to }630\text{ mm}$ (rule of thumb)

Structural Forms

String-beam stairs (strings span landings)
Cranked/Continuous slab
Inclined slab into walls
Cantilever (spine wall)
Precast units
Spiral/Helical (secondary, ≤ $12.2$ m building height)
Layouts: Dog-leg (open/close well), Quarter-turn, Bifurcated, Geometrical

Ramp Design

Slopes: Vehicles $1:7$ ; Pedestrians $1:10$ ; Disabled $1:12$
Landings every $1500$ mm rise/change; width $\ge915$ mm clear (between rails)
Surface slip-resistant; handrails $860$ – $960$ mm above ramp

MATERIALS: Concrete, Cement & Ceramic Products

Bricks

Raw clays: surface, shale, fireclay
Manufacturing: Mining → Crushing → Pug-milling → Extrusion or Soft-mud moulding → Drying → Firing (tunnel kiln) → Cooling/Packaging
Properties influenced by firing: durability, colour (iron oxides; oxidising vs. reducing), compressive strength, absorption
Product Classes:
1. Facing Bricks
- Extruded/Wire-cut (perforated; sharp arrises)
- Soft-mud (hand-moulded, water-struck)
1. Engineering Bricks – Class A >125 N/mm², <4.5\% absorption; Class B >75 N/mm², <7\% absorption

Concrete Blocks (CMU)

Mix: cement : sand : gravel : water (dry‐stiff); standard size $390\times190\times{ 100,200,300 }\text{ mm}$
Types: solid (dense; load-bearing) vs. hollow (voids ≥ $25\%$ ; lightweight aggregate)
Strength ≥ $3$ N/mm²; weight $\approx17$ – $20$ kg (solid)

Pavers

Flexible (bituminous layers) vs. Rigid (concrete slab)
Raw materials proportioned, compacted, cured; used for footpaths, roads, plaza surfaces

Tiles

Roof tiles (clay, concrete, metal) for pitched roofs; enable rainwater run-off, possible grey-water harvest
Floor tiles (ceramic, marble, wood laminates) as finishes over screed & DPM
Wall tiles/cladding for aesthetics & protection; beyond $150$ mm above FFL

EXTERNAL WORKS (Chap 8)

Site Preparation Sequence

Planning – technology, work-breakdown, resource/duration, budget
Survey – topo, utilities, platform levels, as-built recording
Clearing & Grading – remove vegetation/structures, cut-&-fill balance
Temporary Utilities – power, water, lighting, access roads
Mobilisation – site office, cabins, signage, hoarding, worker quarters

Fencing

Purposes: boundary, security, privacy, noise/wind control, landscaping
Materials & Types:
- Timber (post-rail, picket, board; high maintenance)
- Steel (chain-link, ornamental, tubular, livestock)
- Masonry/Concrete (brick, decorative block) – durable but costly

Surface Drainage

Open channels or piped systems to remove excess water; slope guidelines: lawns $1.5$ – $10\%$ , paved $2$ – $3\%$
Highway gullies connect to surface water sewer or SMART tunnel (KL)
Clogged drains → flooding; ensure maintenance

Pavements

Definition: hard surface bearing traffic load (sidewalks, roads)
Materials: concrete, bituminous asphalt, interlocking pavers
Design considerations: pedestrian realm, street crossing, furnishing zone, setbacks; case study – Saloma Bridge KL

Retaining Walls (External scope)

Same principles as sub-structure section; integrate with landscape, access paths