EGB273 Week 13 Principles of Construction Revision PDF

EGB273 Principles of Construction Week 13 – Exam Revision Assoc. Prof. Hafizah Binti Ramli R EGB273 a university for the real world Lecture 13 - 1...

EGB273 Principles of Construction Week 13 – Exam Revision Assoc. Prof. Hafizah Binti Ramli R EGB273 a university for the real world Lecture 13 - 1 CRICOS No. 000213J  Acknowledgement of Traditional Owners The Queensland University of Technology (QUT) acknowledges the Turrbal and Yugara, as the First Nations owners of the lands where QUT now stands. We pay respect to their Elders, lores, customs and creation spirits. We recognise that these lands have always been places of teaching, research and learning. QUT acknowledges the important role Aboriginal and Torres Strait Islander people play within the QUT community. R EGB273 a university for the real world Lecture 13 - 2 CRICOS No. 000213J  Research Project on Student Perception of Embedded Indigenous Perspectives QUT Learning and Teaching Grant led by Dr Craig Cowled QUT Ethics Approval 7789 You are all invited to participate in a research project focused on student perceptions of embedding Indigenous perspectives in the civil engineering curriculum. The purpose of this project is to better understand how students perceive Indigenous perspectives within course content and to explore what students experience as potential threshold learning elements in Indigenous engineering. Anticipated findings from the research will improve the learning experience for future cohorts and inform future curriculum development in Faculty of Engineering. A link to a short anonymous survey will be posted on Canvas. Students can finish the survey outside class, through the same link. At the end of the survey, you will be asked if you are willing to participate in a follow-up interview with a PhD student. Interviews will last approximately 60 - 90 minutes, and you will be compensated with a $50 voucher. If you are interested, a link will redirect you to a separate page where you will enter your contact details. Your decision to participate or not participate will have no impact on your grade in the course. R EGB273 a university for the real world Lecture 13 - 3 CRICOS No. 000213J  Preparation for Exam ▪ EGB273 Final exam on 7 Nov 2024 at 8:30am ▪ Content from Week 7- Week 12 Lecture and Tutorial materials. ▪ Exam format – FOUR questions with subsections. Short answer (description with sketches if needed) and calculation questions. ▪ Answer all questions ▪ Equations given in the appendix R EGB273 a university for the real world Lecture 13 - 5 CRICOS No. 000213J  Week 7 Road Construction R EGB273 a university for the real world Lecture 13 - 6 CRICOS No. 000213J  Road Construction Two phases : The earthworks Cut and fill The preparation of the soil The construction of the pavement R EGB273 a university for the real world Lecture 13 - 7 CRICOS No. 000213J  Road Design Cross Section Excavation (Cut) Cross Section Embankment (Fill) R EGB273 a university for the real world Lecture 13 - 8 CRICOS No. 000213J  Mass Haul Diagram Use in designing the best profile and in organizing the actual work in the most economical manner Provides quick, quantitative information about cut and fill volumes and movements A graphic representation of accumulated volume R EGB273 a university for the real world Lecture 13 - 9 CRICOS No. 000213J  Mass Haul Diagram R EGB273 a university for the real world Lecture 13 - 10 CRICOS No. 000213J  Mass Haul Diagram Chainage 0~ 100~ 200~ 300~ 400~ 500~ 600~ 700~ 800~ 900~ Total (m) 100 200 300 400 500 600 700 800 900 1000 Cut (m3) 490 927 982 279 0 0 0 0 220 428 3326 Fill (m3) 0 0 0 28 205 595 1055 848 84 0 2815 Compacted Fill (m3) 0 0 0 31 226 654 1160 933 92 0 3096 Cumulative 490 1417 2399 2647 2421 1767 607 -326 -198 230 Volume Cut less Fill i.e. Excess Cut +ve Shortfall Fill –ve R EGB273 a university for the real world Lecture 13 - 11 CRICOS No. 000213J  Types of Pavements Classification based on the structural performance: FLEXIBLE PAVEMENT RIGID PAVEMENT R EGB273 a university for the real world Lecture 13 - 12 CRICOS No. 000213J  Pavement Material Flexible pavement Unbound granular and/or stabilised materials and/or asphalt Rigid pavement Concrete pavement with joints and or steel reinforcement Relatively high strength concrete (30 MPa or more) Range of sub-base materials Lean mix concrete Cement stabilised crushed rock Unbound granular materials R EGB273 a university for the real world Lecture 13 - 13 CRICOS No. 000213J  Subgrade R EGB273 a university for the real world Lecture 13 - 14 CRICOS No. 000213J  Subgrade Strength Determines the thickness of the pavement needed and its strength California Bearing Ratio (C.B.R.) (AS 1289.6.1.1) R EGB273 a university for the real world Lecture 13 - 15 CRICOS No. 000213J  C.B.R The test is performed by measuring the pressure required to penetrate a soil sample with a plunger of standard area. The measured pressure is then divided by the pressure required to achieve an equal penetration on a standard crushed rock material. And using the values obtained from the test from an empirical design chart, the pavement thickness are calculated. R EGB273 a university for the real world Lecture 13 - 16 CRICOS No. 000213J  Week 8 Foundation R EGB273 a university for the real world Lecture 13 - 17 CRICOS No. 000213J  What is a foundation? Element of the structure in direct contact with the ground and which transmits the load of the structure to the ground R EGB273 a university for the real world Lecture 13 - 18 CRICOS No. 000213J  Foundation Functions Support for the superstructures Prevent settlement (including differential settlement) Prevent possible movement of structure due to periodic shrinkage and swelling of subsoil Allow building over water or water-logged ground Resist uplift or overturning forces due to wind Resist lateral forces due to soil movement Underpin (support) existing or unstable structures R EGB273 a university for the real world Lecture 13 - 19 CRICOS No. 000213J  Loads on Foundation Dead load of superstructure and foundation Live loads Wind load Water pressure Impact loads Temperature stresses Earth pressure Seismic load R EGB273 a university for the real world Lecture 13 - 20 CRICOS No. 000213J  Selection of foundations Nature of sub-soil (ground conditions) Materials used for the foundation Economical consideration Construction program Layout of structure (building/floor plan, positioning loads etc) Site constraints (location and sufficient work space) Local availability of plant and equipment Acceptable settlement R EGB273 a university for the real world Lecture 13 - 21 CRICOS No. 000213J  Types of Foundation Shallow - Pad Deep - Piled Strip footing, Pad (or Spread) footing, Bored cast in-situ, Driven cast-insitu, Raft (or Mat) footing, Strapped (or Driven precast Combined) footing concrete/steel/timber R EGB273 a university for the real world Lecture 13 - 22 CRICOS No. 000213J  Shallow Foundations Shallow foundations take their name from the level they are founded Depth equal to 3 to 4 times their width Typically lighter load than deep (piled) foundation Much cheaper to construct No specialist equipment needed R EGB273 a university for the real world Lecture 13 - 23 CRICOS No. 000213J  Ultimate Bearing Capacity of shallow foundation Ultimate bearing capacity, qu is the load per unit area of the foundation at which shear failure in soil occurs. Theory for the ultimate bearing capacity of rough shallow foundations by Terzaghi (1943). Surcharge, q=Df Df is the depth of foundation from the ground surface  is the unit weight of soil c’ is the soil cohesion B is the width or diameter of the foundation R EGB273 a university for the real world Lecture 13 - 24 CRICOS No. 000213J Terzaghi’s bearing capacity factors for different soil friction angle ’ R EGB273 a university for the real world Lecture 13 - 25 CRICOS No. 000213J  Allowable load-Bearing Capacity Allowable load-bearing capacity, qall of shallow foundations requires the application of a factor of safety (FS) : The factor of safety should be at least 3. R EGB273 a university for the real world Lecture 13 - 26 CRICOS No. 000213J  Deep - Piled Foundations Transferring foundations to a convenient level, a firm soil stratum with sufficient load carrying capacity R EGB273 a university for the real world Lecture 13 - 27 CRICOS No. 000213J  Piling Types Displacement (driven piles ) – Timber – Precast concrete (sometimes prestressed) – Closed ended steel tube – Steel “H” sections Cast in place – Bulb piles – Bored piles R EGB273 a university for the real world Lecture 13 - 28 CRICOS No. 000213J  Driven Pile - Timber Low cost Renewable supply Long history of successful application Easily handled and driven R EGB273 a university for the real world Lecture 13 - 29 CRICOS No. 000213J  Driven Pile – Precast Concrete Conventionally reinforced Higher strength when prestressed To be manufactured to required lengths, splicing not desirable. Pile driving can be noisy Vibrations can have adverse effects on nearby buildings R EGB273 a university for the real world Lecture 13 - 30 CRICOS No. 000213J  Driven Pile – H Section Relatively expensive Higher load carrying capacity, high resistance to driving Ease of splicing (connection along the length) Marine environments - prone to corrosion and require cathodic protection. Cheng, Y. M et al. (2024). Analysis, design and construction of foundations. Taylor & Francis Group. R EGB273 a university for the real world Lecture 13 - 31 CRICOS No. 000213J  Week 9 Steel Construction R EGB273 a university for the real world Lecture 13 - 32 CRICOS No. 000213J  Fabrication Process Material preparation Material receiving – from the mill or warehouse. Store materials by grade, proper marking Thermal cutting - to create plate of any required shape, to cut holes and bevel the edges for groove welds, cutting to length. Bolt holes can be drilled, punched, or cut thermally. Camber - provide curvature of an element in its major axis. R EGB273 a university for the real world CRICOS No. 000213J  Fabrication Process Assembly, fitting and fastening Bolting – ordinary bolts or high strength friction grip bolts Welding – Shop welding better than site welding for quality control – Require high-skill welder – All welds must be inspected visually Shop assembly – components are brought together to be fitted up – member is inspected for dimensional accuracy, squareness and conformance with shop drawings. R EGB273 a university for the real world CRICOS No. 000213J  Erection Tasks Secure crane information Check transport of member lengths selected Decide laydown area Determine size of yard crane Determine temporary restraint systems Determine painting area if needed R EGB273 a university for the real world CRICOS No. 000213J  Crane Selection – Avoid marginal situations – Consider crane movements in three dimensions – Understand characteristics of different types (rubber tyred / tracked, lattice / telescopic) – Consider operating surface – Be very cautious of multiple crane lifts R EGB273 a university for the real world CRICOS No. 000213J  Crane Selection Draw positions of all critical elements to scale 20 M Determine jib length from trial position 6.3 M Determine max. radius from adopted position Determine min. radius Check jib angle at min. radius (ok) Check for clash with existing steelwork (ok) R EGB273 a university for the real world CRICOS No. 000213J  Steel Erection R EGB273 a university for the real world CRICOS No. 000213J  Steel Erection Option 1 Assemble In Place TEMPORARY SUPPORT TOWERS TEMPORARY WIRE ROPE GUYS 1. Crane location not critical 2. Guys must remain until sufficient steelwork erected To allow permanent bracing members to be installed 3. Time consuming but permits careful progress R EGB273 a university for the real world CRICOS No. 000213J  Option 2 Assembled On Slab And Stood As Unit EXISTING STEELWORK 8M NEXT PORTAL LOCATION ASSEMBLY AND PICKING UP RADIUS SLINGING AT QUARTER POINTS ERECTING RADIUS PITCHING RESTRAINTS PLUMBING RADIUS CRANE 2 CRANE 1 AS FOR CRANE 1 1. Portal assembled on slab clear of erected work 2. Crane positioning critical 3. Rubber tyred cranes should not travel with load R EGB273 a university for the real world CRICOS No. 000213J  Option 2 Crane Motions 1. Cranes kept as close as practicable 2. Sketch required to detect clashes 3. Existing work provides bracing R EGB273 a university for the real world CRICOS No. 000213J  Week 10 Concrete Construction R EGB273 a university for the real world Lecture 13 - 42 CRICOS No. 000213J  Formwork Industry standard practices – Ply facing and timber backing - adopted for basic work – Ply facing and steel backing - used for repeated operations – Steel forms - used for manufactured products R EGB273 a university for the real world Lecture 13 - 43 CRICOS No. 000213J  Formwork Industry standard practices – Telescopic steel props/frames - used to support forms – Jump form technique used in high-rise, silo construction, cooling towers R EGB273 a university for the real world Lecture 13 - 44 CRICOS No. 000213J  Slip Form Jump Form R EGB273 a university for the real world Lecture 13 - 45 CRICOS No. 000213J  FORM Slip Form & Jump Form CANTILEVERED NEW TIES REINFORCING SPECIAL TIES CAST IN PREVIOUS POUR STEEL SOLDIERS PACKING JUMP FORM SLIP FORM RATE OF ADVANCE CRITICAL PREVIOUS POUR FORM JUMPED TO NEXT LEVEL R EGB273 a university for the real world Lecture 13 - 46 CRICOS No. 000213J  Slip Form VS Jump Form The main difference between the two is that slipform uses a structure’s core of shaft for its support, and it moves up slowly as concrete is poured in one long, slow pour. This eliminates the need for waiting for each level to dry. Slipform is great for creating tapered structures with walls that have thickness that contracts at various levels. In general, this type of self-climbing formwork system is considered to be more efficient than jump form for particularly high buildings, especially those over ten stories. Slipform usually consists of three platform stations. The lowest station is used for the finishing of concrete. The middle station is used at the highest level of where concrete is poured, and the highest station is where materials for the project are stored. Slipform creates a continuous, smooth, and highly precise concrete end product with no joints from jumping. This is ideal for structures where joints won’t be covered up, particularly for structures like chimneys and bridge pylons. A downside of slipform in comparison to jumpform is that it’s usually a bit more expensive, and it requires workers to attend to concrete pours for longer consecutive hours. R EGB273 a university for the real world Lecture 13 - 47 CRICOS No. 000213J  Prestressed Concrete (PSC) Initial compression is given in the concrete before its application To counteract the tensile stresses due to external load. R EGB273 a university for the real world Lecture 13 - 48 CRICOS No. 000213J  Methods of prestressing Two techniques i.e. difference being whether the steel tensioning process is performed before of after the hardening of concrete. Pre-tensioning Post-tensioning Choice of method is governed by the type and size of member and the need for precast or in situ construction. R EGB273 a university for the real world Lecture 13 - 49 CRICOS No. 000213J  Pre-tensioning Pre-tensioning depending on the bond The tendons generally have small diameter wires or small strands which have good bond characteristics. The method is ideally suited for factory production where large numbers of identical units can be economically made under controlled conditions. Several units can be cast at once – end to end – and the tendons merely cut between each unit after release of the anchorages. R EGB273 a university for the real world Lecture 13 - 50 CRICOS No. 000213J  Pre-tensioning FORMWORK HIGH STRENGTH WIRES DEAD END JACKING END STEEL PRETENSIONING BED STAGE 1 1. High strength wires are strung between fixed posts of a permanent bed 2. Hydraulic jacks are used to stretch the wires which are then locked off 3. Shear and bursting reinforcing is placed around the wires 4. Formwork is assembled to the shape of the particular product 5. Concrete is poured R EGB273 a university for the real world Lecture 13 - 51 CRICOS No. 000213J  Pre-tensioning FORMWORK WIRES CUT WHEN CONCRETE CURED COMPRESSIVE FORCE INDUCED INTO MEMBER DEAD END JACKING END STEEL PRETENSIONING BED STAGE 2 1. Steam curing used to force cure the concrete to release the bed early 2. When concrete is cured sufficiently wires are cut to transfer force to concrete 3. Finished product is lifted out of bed and stored and cycle repeats R EGB273 a university for the real world Lecture 13 - 52 CRICOS No. 000213J  Post-Tensioning Suitable for in situ construction Stressing against the tendons which are not bonded to the concrete. The tendons are passed through a flexible ducting, which is cast into the concrete in the correct position. Tendons are tensioned by jacking against the concrete, and anchored mechanically by anchorage blocks at each end of the member. After stressing, the remaining space in the ducts may be left empty (“unbonded” construction) or more usually will be filled with grout under high pressure (“bonded” construction). R EGB273 a university for the real world Lecture 13 - 53 CRICOS No. 000213J  Post Tensioning CONCRETE BLOCKS LIGHTLY REINFORCED PLAIN ROD THREADED ROD AND WEDGES AND NUT DUCT FORMER HIGH STRENGTH HEAVY WASHER ANTI BURSTING STEEL ROD REINFORCING 1. Blocks, with duct tube installed, cast and allowed to cure 2. Rods passed through ducts 3. Rods stretched with hydraulic jack and locked with nut 4. Annular space filled with cement grout R EGB273 a university for the real world Lecture 13 - 54 CRICOS No. 000213J  Comparison – Pre- and Post-Tensioning Pre-tensioning: Post-tensioning: – Cables are placed in the – Cables are placed in ducts and left formwork and stressed. unstressed. – Concrete is poured and – Concrete is poured but cannot bond to the bonds directly to the cables as they are protected by the ducts. cables as it hardens. – After the concrete has hardened, the – Cables are released, cables are stressed by tensioning the placing the concrete in cables directly against the ends of the compression. concrete, placing the concrete in compression. – The cables are locked-off or anchored against the ends the concrete member to maintain the stress. – The ducts are then grouted to bond the cables. R EGB273 a university for the real world Lecture 13 - 55 CRICOS No. 000213J  Week 12 Bridge Construction R EGB273 a university for the real world Lecture 13 - 56 CRICOS No. 000213J  Types of Construction Three basic types: Beam Arch Cables Simply Member in Cable-hung supported compression decking Continuous Load Support by Cantilever transferred tower into Suspension horizontal Cable- thrust stayed R EGB273 a university for the real world Lecture 13 - 57 CRICOS No. 000213J  Bridge elements SPAN SIMPLY SUPPORTED DECK ABUTMENT HEADSTOCK PIER SUBSTRUCTURE VARIATIONS IN COMMON USE R EGB273 a university for the real world Lecture 13 - 58 CRICOS No. 000213J  Bridge elements SEQUENCE OF CONSTRUCTION TYPICAL PRESTRESSED BOX GIRDER SUITED TO SPANS UP TO 30 METRES HEADSTOCK Pile cap Typical medium span bridge R EGB273 a university for the real world Lecture 13 - 59 CRICOS No. 000213J  Bridge elements Bearings Transmit loads from deck/girder to substructure Allow controlled movement due to Roller bearing Pin bearing Pin bearing temperature variation or seismic activity Lin, Weiwei & Yoda, Teruhiko. (2017), Bridge Engineering - Classifications, Design Loading, and Analysis Methods ,Elsevier. Elastomeric bearing R EGB273 a university for the real world Lecture 13 - 60 CRICOS No. 000213J  Foundations Heavy foundations require heavy equipment Frequently constructed in water impeding access Often influenced by tidal conditions Create the most unpredictability of all activities Inevitably on the critical path R EGB273 a university for the real world Lecture 13 - 61 CRICOS No. 000213J  Substructures Abutments Vertical supports at the ends Function as retention walls for the ground Piers At the ends of bridge spans, between the abutments Complicated shapes (design influenced by aesthetics) Vulnerable to damage during construction (flooding) Headstocks Provide space for girders to transfer loads on bearings Complicated shapes (design influenced by aesthetics) Formwork difficult to support (height and overhang) R EGB273 a university for the real world Lecture 13 - 62 CRICOS No. 000213J  Superstructures Includes deck, girder, truss, bracings, tower, cables, hangers Difficult construction Generally cannot be supported from ground during construction Require handling heavy weights at significant heights Erection loads frequently exceed working loads Long span makes control of dimensions difficult Materials Steel, reinforced concrete, prestressed concrete Composite steel/concrete, composite fibre concrete R EGB273 a university for the real world Lecture 13 - 63 CRICOS No. 000213J  Arch Bridge Construction Using Cantilever Method TEMPORARY CABLE STAY PIER SEGMENT 2 SEGMENT 1 ARCH RIB (CAST USING TRAVELLING FORM) ARCH RIB FOUNDATION R EGB273 a university for the real world Lecture 13 - 64 CRICOS No. 000213J  Arch Bridge Construction Using Cantilever Method Temporary Tower Temporary cable stay Segment 3 Segment 2 Segment 1 R EGB273 a university for the real world Lecture 13 - 65 CRICOS No. 000213J  Arch Bridge Construction Construction completed R EGB273 a university for the real world Lecture 13 - 66 CRICOS No. 000213J  Arch Bridge Construction Using falsework Space filled by falsework Construct arch Bridge deck formed on top Once it is self-supporting, falsework removed. Typical construction for masonry arches and in situ concrete. R EGB273 a university for the real world Lecture 13 - 67 CRICOS No. 000213J  Suspension Bridges Sequence of erection CABLES BUILT UP BY ADDING ADDITIONAL WIRES SUSPENSION CABLES TENSIONED WIRE STRUNG TO CORRECT CATENARY CURVE ACROSS RIVER DECK SECTIONS TOWERS LIFTED FROM BARGE 1) Install towers 2) Strung wires across river 3) Tension suspension cables to correct catenary curve anchors to both end supports 4) Cable built up with additional wires 5) Lift deck from barge and connect to vertical cables/wires 6) Continuous survey to maintain level in every stage within tolerance R EGB273 a university for the real world Lecture 13 - 68 CRICOS No. 000213J  Cable Stayed Bridge 1) Install left hand side mast and part deck with temporary struts 2) Cable stays tensioned to predetermined loads 3) Install continuous decks to either side, keeping structure in balance 4) Link deck with cables to mast and anchored STRUCTURE KEPT IN 5) Use kentledge to provide balance while the outer decks are continuously uplifted and BALANCE connected with cables to mast. BY DEVELOPING 6) Repeat the same process from right hand side SYMETRICALLY 7) Continuous survey to maintain level in every stage within tolerance EITHER SIDE OF PIER UNTIL ABLE CABLE STAYS TENSIONED TO BE ANCHORED TO PREDETERMINED LOADS STRUCTURE CAN NOW BE DEVELOPED ASYMETRICALLY WITH KENTLEDGE USE TO ASSIST WITH BALANCE TEMPORARY STRUTS R EGB273 a university for the real world Lecture 13 - 69 CRICOS No. 000213J