(xii) Sample and test additional test cylinders to demonstrate when the required strength has been achieved. than either: The volumetric ratio of spiral reinforcement and the total gross Asummary of the influence of design and detailing on the safety of deteriorating concrete structures is available in this post. As with shrinkage, the likely consequences are contractions and deflections. In taller structures vertical shortening of heavily loaded members relative to other (non-load-bearing) members could cause problems. tests are made to establish the relationships between concrete allowing larger ducts in the webs of HSC members. The bridge under construction using the balanced cantilever method. HSC. Otherwise, the development length, ld, measured from the Researchers at FHWA have suggested new equations for transfer and moment is relatively large in this application because of the large For coring from prestressed concrete the requirements of Clause610.16 shall be satisfied. (iii) Heavy Jack Picking a coarse texture achieved through jack picking the concrete surface. You can download the paper by clicking the button above. [Equation 72], (5.8.4.1-2) Shear forces are at their highest in support regions. VicRoads VicRoads October 2017 Section 610 (Page 1 of 50) VicRoads October 2017 Section 610 (Page 2 of 50) VicRoads October 2017 Section 610 (Page 3 of 50) VicRoads October 2017 Section 610 (Page 4 of 50) VicRoads October 2017 Section 610 (Page 5 of 50) VicRoads October 2017 Section 610 (Page 6 of 50) VicRoads October 2017 Section 610 (Page 7 of 50) VicRoads October 2017 Section 610 (Page 8 of 50) VicRoads October 2017 Section 610 (Page 9 of 50) VicRoads October 2017 Section 610 (Page 10 of 50) VicRoads October 2017 Section 610 (Page 11 of 50) VicRoads October 2017 Section 610 (Page 12 of 50) VicRoads October 2017 Section 610 (Page 13 of 50) VicRoads October 2017 Section 610 (Page 14 of 50) VicRoads October 2017 Section 610 (Page 15 of 50) VicRoads October 2017 Section 610 (Page 16 of 50) VicRoads October 2017 Section 610 (Page 17 of 50) VicRoads October 2017 Section 610 (Page 18 of 50) VicRoads October 2017 Section 610 (Page 19 of 50) VicRoads October 2017 Section 610 (Page 20 of 50) VicRoads October 2017 Section 610 (Page 21 of 50) VicRoads October 2017 Section 610 (Page 22 of 50) EMBED Word.Picture.8 VicRoads October 2017 Section 610 (Page 23 of 50) VicRoads October 2017 Section 610 (Page 24 of 50) VicRoads October 2017 Section 610 (Page 25 of 50) VicRoads October 2017 Section 610 (Page 26 of 50) VicRoads October 2017 Section 610 (Page 27 of 50) VicRoads October 2017 Section 610 (Page 28 of 50) VicRoads October 2017 Section 610 (Page 29 of 50) VicRoads October 2017 Section 610 (Page 30 of 50) VicRoads October 2017 Section 610 (Page 31 of 50) VicRoads October 2017 Section 610 (Page 32 of 50) VicRoads October 2017 Section 610 (Page 33 of 50) VicRoads October 2017 ! " 610.30 PROTECTIVE MEASURES FOR CONCRETE STRUCTURES SUBJECT TO SULPHATE AND CHEMICAL ATTACK Concrete structures subject to sulphate and chemical attack with a pH lower than5.0, or where highly mobile ground water conditions exist or high exchangeable soil acid conditions prevail the environment shall be assessed as exposure classificationU and be subject to special consideration. Download. The slump of the concrete shall be checked and recorded within 45minutes of adding cement to the aggregate, or immediately prior to discharge when the actual haul time exceeds 45minutes and/or when water is added to the mixed batch in accordance with Clause610.13(a). Consequently, the Where applicable, concrete in the existing structure shall be broken back as shown on the drawings. This also causes loss of prestressing force because additional strain occurs after the structure is completed. This was caused by a combination of overload and low strength concrete. Article 5.11.2.1.2, where applicable. The Contractor shall not proceed with the placement of concrete until the hot or cold weather concreting procedure has been reviewed and approved by the Superintendent. following factor: HSC usually has lower creep than conventional strength concrete, so 4.8.2 Forces on connections. (e) Delivery Docket In addition to the information required by Clause1.7.3 of AS1379 the following information shall also be recorded on the delivery docket: (i) the total water in the batch, including - (1) the moisture content of both fine and coarse aggregates as specified in Clause610.13(d) (2) batch water (3) water added at the slump stand (4) total amount of water permitted to be added on site (5) water added on site before commencement of discharge, including water used to wash down the mixing blades of the mixer or agitator (ii) cement brand and type, including - (1) proportions of components (by mass) (2) total mass of cement (iii) chemical admixtures, including - (1) types (2) amounts (iv) slumps, including - (1) nominated slump (2) estimated slump (3) measured slump (v) any other additions to a batch (vi) the unique identification number allocated to the concrete mix design in accordance with Clause610.07(b)(xiii). 610.09 WATER The quality of water to be used in the concrete mix and for the curing of concrete shall comply with the requirements of Clause2.4 of AS1379. (v) Steam Delivery Under no circumstances shall steam jets be allowed to impinge upon any part of the concrete units or of a test specimen, or of their formwork or moulds. length, lhd, in inches, of welded deformed wire fabric, measured from the point of critical section to the end of wire, shall not be less than either: The yield strength of welded plain wire fabric shall be considered The minimum requirements of Clause610.23(g)(iii) shall be complied with. (e) Evaporation Limits for Concreting Operations The Contractor shall be responsible for measuring and recording the air temperature, relative humidity, concrete temperature and wind velocity (measured one metre above the as placed concrete) at the point of concrete placement from commencement of placing the concrete and continue until curing has commenced. Equation 5.13.2.5.5-3 should be verified for use with HSC. The development length, ldh, in inches, for deformed in table 3.4.1-1. However the internal restraint provided by the aggregate reduces the magnitude of this volume change to about 0.05%. The shrinkage of concrete was explained in details in the Section 1.0, Concrete (Part II). Report is focused on the design of slab, beam (primary and secondary), column (square and circular), staircase (open newel and spiral), concrete dome roof and foundation (raft foundation and isolated footing). WebDESIGN OF PRESTRESSED CONCRETE. document being reviewed and not the sections, articles, or tables Strength in excess of 3.50 ksi at the time of prestress. 209 as modified by additional published data. WebEnter the email address you signed up with and we'll email you a reset link. The sum of Portland cement and other cementitious materials shall (iii) Above Deck Surface All surfaces above the tops of kerbs shall have a Class3 surface finish. of concrete, metal, and wood, or combinations thereof, subject to Those equations should be reviewed for their appropriateness with He has worked at both the Cement andConcreteAssociation (C&CA) and theBritish CementAssociation (BCA) where he developed guidance for assessing the safety and service life of deteriorating concrete structures. from the 50diameters used in the AASHTO Standard The cracking B1 B2 Pages: 754. The end result of the project is stated under the Shear links have lower covers than flexural steel and will thus corrode first. Any concrete which is exposed to rain or other precipitation within the period from placement to curing will be nonconforming. (f) Period for Completion of Discharge Concrete shall be placed and compacted within 60minutes of the commencement of mixing. Mike led an independent review of CDM 1994 and the independent evaluation of CDM 2007. WebEnter the email address you signed up with and we'll email you a reset link. There have been cases of catastrophic failure due to axial overload in columns. Critical issues for the AM of structural materials, including the printability, printing resolution/scalability/speed, geometric complexity, mechanical robustness, and cost-efficiency, are discussed, and the current factors as specified in Article 5.5.4.2, and the following The main consequence likely is loss of cover to any reinforcement that is present. Restraint to this contraction can lead to cracking in the surface layers. equations do not reflect the higher prestress levels used with HSC. may not be available at the design stage. When making test cylinders for SCC the test sample shall be placed into the cylinder moulds from a height not exceeding 100mm from the top of the mould. (iii) Cracks over 2mm shall be repaired with filling materials and methods in accordance with the requirements of Section687. concrete at 28 days, unless another age is specified (ksi) the core to offset the loss of strength when the concrete shell is with specific cementitious materials. The outer layers will try to contract more than the inside. All cores shall be clearly labelled to identify them with the structural member and location they represent. defined. this article. It is conceivable that 1.2 times the The most common advantage of a rigid frame bridge is that the superstructure and substructure are connected, so no supports are required. 4.0 ksi, except that 1 shall not be taken less than (vi)Profile in a Horizontal Plane (Bow)The deviation of a unit from the required profile shall not exceed 6mm or 0.10% of the length of the unit, whichever is the greater. In this review article, we present recent progress and advances in 3D/4D AM of various materials, and their potential applications. perpendicular to the neutral axis. Table 610.131 Properties of SCCMeasurementObservationsSlump Flow550 750 mm spreadThe aggregate shall be evenly distributed throughout the concrete paste within the spread and shall not exhibit signs of segregationT500 time (measure of viscosity)Achieve a spread of 500mm within 2to5 secondsThe final spread shall not exceed 750mm in diameterPassing Ability d" 1 0 m m T h e c o n c r e t e s h a l l n o t e x h i b i t s i g n s o f s e g r e g a t i o n ( c ) H i g h l y W o r k a b l e C o n c r e t e H i g h l y w o r k a b l e c o n c r e t e s h a l l b e s u p e r p l a s t i c i s e d w i t h a n o m i n a t e d s l u m p o f b e t w e e n 1 6 0 m m a n d 2 2 0 m m a n d s h a l l b e c o m p a c t e d i n a c c o r d a n c e w i t h t h i s s e c t i o n . through the joints, which is sufficient to carry the should be investigated using Load Combination Service III specified Table 610.161 Volume Cast in One Continuous Operation (cubic metre)Minimum Number of Samples0 to 10110 to 25225 to 50350 to 1004For each additional 50m one additional sample shall be taken. Thus, 1.33 times the Specifications deals with concrete structures. It may be possible to have higher stress Should the strength of any one sample representing the concrete fall short of the specified minimum 28day compressive strength as shown in Table610.051, the concrete represented by that sample may be rejected or the Contractor may elect to test concrete cores subject to approval by the Superintendent. For rectangular or flanged sections subjected to flexure about one The following assumptions may be used in the design of reinforced, prestressed, and partially prestressed concrete components: An effective modular ratio of 2n is applicable to permanent loads Furthermore, there are ways to reduce the permeability without Furthermore, since errors can be corrected for each construction stage, it can increase the precision of construction. Bar chairs and spacers which do not comply with the requirements of this section shall not be used in the Works. Segments incorporating a transverse diaphragm shall be cast monolithically with the full cross section of the webs, floor and deck slab extending a distance of at least five metres from the face of the diaphragm. (ii) Hardened Concrete In addition to the requirements of Clause 610.16(g)(ii) for compressive strength of test cores, a minimum of two cores per sample shall be cut from the relevant completed structural member, portion of member or group of members represented by a set of test cylinder sample(s) and tested at 28days. 610.45 FIRE RESISTANCE OF CONCRETE Where required fire resistance of concrete shall be as specified in the drawings and specification and shall comply with the requirements of AS5100.5. For components with bonded prestressing tendons or ledges of inverted T-beams shall be the lesser of that specified by Mike has been instructed as an expert witness by both defence and prosecution teams in cases involving allegations of gross negligence manslaughter, breaches of the Health and Safety at Work Act and the CDM Regulations and the appeal of enforcement notices. We use cookies to help provide and enhance our service and tailor content and ads. stress in the node regions of the strut shall not exceed: The appropriateness of the maximum values of the concrete The specification will be satisfied if the VPV value for each sample, as determined from the average value of the test cores, is not larger than the specified maximum VPV values at 28days as shown in Table610.061. (vii)TwistThe angular rotation of any cross section relative to an end cross section shall not exceed 1in200. lost may not be appropriate for HSC. sections with non-rectangular geometry. Equation 2 and Equation 3. (iv) When 20MPa is reached the speed limit can be increased to 60km/hour until the concrete reaches aminimum strength of 32MPa at which point the lane closure ends and the speed limit can increase to 80km/h. Also, HSC has less lateral expansion than conventional strength concrete, so the effect of confinement is less. The W/C ratio of the proposed concrete mix design shall not be less than 0.30 for concrete cast insitu works and 0.28 for concrete utilised in precast works. Any point at which the placing of concrete has stopped and the concrete has taken its initial set shall be treated as a construction joint. The Contractor shall implement quality procedures and undertake the works in a manner which minimises the effects of traffic induced vibrations, differential deflections and stresses on the new deck widening and in the vicinity of the stitch pour and staged deck overlay, including: (a) adverse effects on the bond between the steel reinforcement and the fresh concrete (b) development of any voids between the steel reinforcement and fresh concrete (c) adverse effects on the mechanical bond at the joint interface (d) adverse effects on bonded anchors if they are used in accordance with Section680 (e) cracking during the early hardening and strength developing period. WebThe burden of repeated calculations in analysis has been reduced due to use of computer software. For segment division, the segment length and weight must be kept constant. The concept for providing spiral reinforcement to strengthen The compilation in this section is based on the AASHTO LRFD 610.42 COVER AND SPACING REQUIRED FOR CONCRETE PLACEMENT The minimum cover required for concrete placement and the minimum allowable steel reinforcement spacing within a concrete member shall not be less than 1.5times the maximum size of aggregate in the concrete mix or the reinforcement bar diameter, whichever is the larger, unless greater concrete placement requirements apply as per AS5100.5, to ensure that the concrete can be satisfactorily placed, flow and compacted around the steel reinforcement. (2) Concrete Prism Test Method (RC 376.04) Aggregates shall be classified reactive when the average expansion at 12 months is greater than 0.03%, and non reactive when it is equal to or less than 0.03%. coefficient seems to depend on the specific materials in the Modify geometric properties (in order of increasing costs) a. carrying on further mathematical manipulation, the equations can be ACTION: A revision to increase the maximum cementitious [Equation 50], (5.7.4.2-1) Research problem statements are included in appendix F. The provisions in this section apply to the design of bridge and A bridge type constructed using the cantilever method in which the central joint is treated as a hinge. Reinforcement supports and spacers shall be in accordance with Clause610.29(f). The balanced cantilever bridge is a prestressed girder bridge and refers to a bridge constructed using the balanced cantilever method. supported by analysis or experimentation, the concrete compressive hf. Where placing concrete would otherwise necessitate a drop exceeding two metres, suitable tremie pipes, chutes or other concreting devices shall be used to place the concrete to prevent segregation. B1 B2 Pages: 754. Test certificates, material data sheets and health and safety data sheets shall be available for all materials. Further information is contained in Reference 7. 610.31 SURFACE FINISH (a) General For any particular class of concrete surface finish, the method of construction and the materials used in the concrete and formwork shall remain consistent and shall be such as to comply with the requirements of this specification. Occasionally, it may be appropriate to use materials other than ! 5.8.2.4, the area of steel shall not be less than: Equation 5.8.2.5-1 is similar to that developed for ACI 318 to allow for an increase in the minimum amount of shear HP Lane closures and speed restrictions shall not be removed until PPV measurements, maturity testing, temperature monitoring and compressive strength test results have been reviewed by the Superintendent. The test certificates shall present the results of uniformity testing of the curing compounds for both non-volatile content and density in accordance with AS3799 Clause3.2, and for viscosity in accordance with AS3799 Clause3.1.5. Manufactured sands produced from any igneous or metamorphic rock shall have a Degradation Factor Crusher Fines of not less than60. (a) Protection Against Ingress of Chlorides (i) All reinforcement and embedded metallic fixtures shall be protected against chloride contamination. HSC. these equations should be evaluated for use with HSC. 0.135 and 0.155 kcf. (d) Wet Weather Concreting Concrete shall not be placed during rain or when rain appears imminent. The specification will be satisfied if the VPV value for each sample, as determined from the average value of the test cylinders, is not greater than the specified maximum 28day VPVvalue in Table610.061. (ii) Sulphate Content The sulphate content of concrete as placed, expressed as the percentage by mass of acidsoluble SO3 to the total cementitious material in the concrete mix shall not be greater than5%. Very fine tensile flexural cracks are to be expected in reinforced concrete under service loads. In addition to the early age compressive strength requirements of this sub-clause 610.16(l), the Contractor shall also comply with the curing requirements of Clause 610.23 and the minimum curing period requirements as stated in Table 610.231. A high level of supervision shall be employed to ensure that the required level of intense compaction is achieved and the rigidity of formwork is maintained during concrete placement. One is instantaneous loss/Immediate loss, and the other is time dependent loss/long-term prestress loss. inches. Construction work is relatively fast because all work is performed identically and repeatedly. Further information is contained in Reference 3. known to have proportionately higher tensile strength than It is primarily caused by the rate of water evaporation exceeding the rate of bleeding. 610.18 PLACING AND COMPACTING CONCRETE (a) Placing General The Contractor shall submit a detailed work method statement(s) (WMSs), inspection and test plan(s)(ITPs) and quality control checklist(s) for all concrete construction works which explicitly reference the acceptance criteria and all performance requirements of Sections610, 611, 613 and 614, for review by the Superintendent not less than 4weeks prior to the placement of concrete. [Equation 49], (5.7.3.1.1-2) Random and aligned cracks can occur with widths of up to 10mm. (c) Trial Mix In the absence of recent documentary evidence that the concrete mix design complies with the requirements of this section, a trial mix shall be undertaken in accordance with AS1012.2. 610.24 CRACKING OF CONCRETE (a) General The Contractor shall plan the various construction activities and control the supply and delivery of concrete, placing, compacting, finishing, curing and protection of freshly cast concrete such that cracking in concrete members is prevented. Mg/m3 (155 lb/ft3). angela nondi. not be taken to be greater than 1.7. HOBBS, D. W. Concrete deterioration: causes, diagnosis and minimising risk. Members are made from normal-weight concrete. The finished concrete surface shall be protected from mortar slurry, physical damage, spillage and water borne staining. If you are a bridge engineer, you may have heard about the Free Cantilever Method or the Balanced Cantilever Bridge. section is reinforced to its maximum limit. For example, in a cantilever there would be tensile stresses in the top face. Internal freeze-thaw damage can result from water freezing in pores, voids and cracks within the concrete. When seismic design is not considered, the horizontal force is mainly due to temperature loads and vehicle's braking loads, and supports can be designed for this amount. Increased microfibril angle in the S2 layer decreases cell wall tensile strength and stiffness but increases the durability. Thus, the of a member increases with an increase in concrete strength. 1.7 ld. Construction joints shall be perpendicular to the principal lines of stress, and in general shall not be located in regions of maximum bending or maximum shear.
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