SANS 10120-5 F-1983 Code of practice for use with standardized specifications for civil engineering construction and contract documents Part 5 Contract administration Section F Pil.pdf

1、 Collection of SANS standards in electronic format (PDF) 1. Copyright This standard is available to staff members of companies that have subscribed to the complete collection of SANS standards in accordance with a formal copyright agreement. This document may reside on a CENTRAL FILE SERVER or INTRA

2、NET SYSTEM only. Unless specific permission has been granted, this document MAY NOT be sent or given to staff members from other companies or organizations. Doing so would constitute a VIOLATION of SABS copyright rules. 2. Indemnity The South African Bureau of Standards accepts no liability for any

3、damage whatsoever than may result from the use of this material or the information contain therein, irrespective of the cause and quantum thereof. Clause 1 . 1.1 2 . 2.1 2.2 2.3 3 . 3.1 3.1.1 3.1.2 3.1.3 3.1.4 3.1.5 3.1.6 3.1.7 3.1.8 3.1.9 3.1.10 3.1.11 3.1.12 3.2 3.2.1 3.2.2 3.2.3 3.2.4 3.2.5 3.2.6

4、 3.2.7 3.2.8 3.2.9 3.2.10 3.2.11 4 . 4.1 4.2 Drawing F-5.1 PART 5 : CONTRACT ADMINI STRATION SECTION F CONTENTS SABS 0120 : Part 5 Section F-1983 Piling . START OP CONSTRUCTION eneral . IMMEDIATELY AFTER THE HANDING OVER OF THE SITE Approval of Detail Sheets (If Any) . Setting Out working Level for

5、Piling . DURING CONSTRUCTION . Contract Administration Permanent steel casings . Obstructions Equipment for inspection of holes . . Alternative designs Inspection of preformed holes . Mechanical coupling devices for precast piling . Water jetting Heaved cast-in-situ piles Piling records Tests and in

6、terpretation of Danish test curves . Guarantee . standing time . Methods of Construction Piling hammer. leaders. and protection devices Subsoil conditions differ materially from those shown on drawings . Expeditious augering and boring of pile holes . . Disposal of spoil . Backfilling of pile bores

7、. Soft rock sockets Construction of rock sockets . Installation of piles in soil likely to heave Driving through fill of depth greater than 2 m Construction of multi-bulb piles Testing . QUALITY CONTROL AND OTHER CONSIDERATIONS General . Disputes Page Number DRAWINGS Typical graphs of penetration du

8、ring tests August 1983 Approved hy the COUNCIL OF THE SOUTH AFRICAN BUFUXU OF STANDARDS 1 SABS 1200 F : PILING SABS 0120 : Part 5 Section F-1983 Piling NOTE: The clausc iumber(s) given at the beginning or after the heading of a clause is/are, unless otherwise stated, the number(s) of the relevant cl

9、ause(s1 of SABS 1200 F. START OF CONSTRUCTION GENERAL. For the purposes of this part of the code, cont-ract administration starts with instructions to the contractor to commence work as set out in Subclause 4.1 of Section 0. IMMEDIATELY AFTER THE HANDING OVER OF THE SITE APPROVAL OF DETAIL SHEETS (I

10、F ANY). If detail sheets have not been signed before acceptance of the tender (as should have been done), to minimize the risk of costly delays and disputes (see 4.2 below), the contractor should ensure that the details set out on the detail sheets (which should have been carefully considered and co

11、mpleted at the tender stage) are, after amendment, if necessary, agreed with and signed by the engineer before work is started. (Sec Subclause 1.3.6 of Section F of Part 3 of the code. ) NOTE: The use of an incorrect method or the wrong equipment for a particular geotechnical condition may so retard

12、 installation that other subsequent construction programs are upset. SETTING OUT (Subclause 5.1.5). When the contractor sets out the pile positions he should make due allowance for the offset of raking piles where the level from which the piles are to be driven is different from that of the undersid

13、e of the pile cap. WORKING LEVEL FOR PILING (Subclausc 5.1.6). Before work commences, the contractor should, in his own interest, ensure that the engineer has agreed on and established an average ground surface as the working level from which piling is to be measured. In order to achieve this it is

14、essential that the contractor should advise the engineer of the date on which he intends to commence piling. DURING CONSTRUCTION CONTRACT ADMINISTKATION Permanent Steel Casings (Subclause 3.2). Permanent steel casings that comply with the requirements for Grade 1 of ASTM A 252 will have the followin

15、g characteristics and the steel will have been made by the open-hearth, the electric-furnace, or the basic-oxygen process: a) The material will have the following tensile properties: Tensile strength, min. 345 MPa Yield point, min. 205 MPa Basic minimum elongation for walls of thickness 5 m and more

16、: Elongation in 200 mm 18 % Elongation in 50 mm 30 % b) The outside diameter of the steel casings will not vary by more than 1 X from the diameter specified. C) The minimum wall thickness at any point will be at least 87,5 % of the wall thickness specified. Obstructions (Subclauses 3.4, 5.8, and 8.2

17、.5) Where the information provided by the contractor in terms of Subclause 5.8 of SABS 1200 F indicates the presence of one or more obstructions that have not been scheduled , or are different from those scheduled, a) the engineer should agree with the contractor on a classification or identificatio

18、n of the obstruction(s) and take steps to ensure reasonable payment in terms of the conditions of contract, and b) the contractor should state his proposed method(s) of overcoming the obstruction(6) and advise the engineer of any claims for plant, standing time, or relocations of plant that are cont

19、emplated (see 3.2.2 below). Equipment for Inspection of Holes (Subclauses 4.3 and 5.2.4). Where construction work falls under the Mines and Works Act, prior approval for persons to be lowered down pile holes must be obtained from the inspector for the area, and the contractor should ensure, in addit

20、ion, compliance with the code of practice referred to in Subclause 4.3 of SABS 1200 F. Alternative Designs (Subclauses 5.1.3 and 8.1.2). Whcre an alternative design has been accepted, both parties to the contract should be particularly punctilious in keeping a close record of the strata disclosed du

21、ring the execution of the work and in ensuring that the records are available in the event of a dispute in regard to paynient. (See 4.2 below and Subclauses 1.3.1 and 1.3.2 of Section F of Part 3 of the code. ) Inspection of Preformed Holes (Subclause 5.2.4). Subclause 5.2.4 of SABS 1200 F requires

22、the contractor to wait for an excavation to be inspected before carrying on with installation. The engineer has to inspect the hole for purposes of quality control and measurement of depth. Immediately after he has been informed that an excavation is ready for inspection, the engineer should inspect

23、 it, and thereafter issue his written acceptance of the pile excavation as quickly as is practicable to avoid disruption of the work. Mechanical Coupling Devices for Precast Pilj-ng (Subclause 5.6.4.5). Well in advance of the need arising to use them, the contractor should submlt to the engineer for

24、 approval details of the mechanical coupling devices he proposes to use. SABS 0120 : Part S Section F-1983 Piling Water Jetting (Subclauses 5.7.2.1 to 5.7.2.5). In view of the serious loss of bearing capacity thaf may be incurred by water jetting or by excrssive water jetting, the contractor should

25、ensure that agreement to the effect that water jetting is necessary to assist driving, is reached with the engineer well before the equipment is moved onto the site and jetting is started. Heaved Cast-in-Situ Piles (Subclause 5.7.3). Where cast-in-situ piles have heaved and the contractor is under a

26、n obligation to check the integrity of the piles, he should ascertain from the engineer the test load program required. It should he noted that the contractor is required to pay for the tests if the piles fail the test, provided that, if this type of plle has been specified and the contractor has co

27、nstructed the piles in the manner specified, the employer will have to pay for the tests. Piling Records (Subclause 5.91 Because it is more practicable for the contractor than the engineer to maintain the necessary continuous supervision for measurement for payment purposes, it is in the best intere

28、sts of all parties to the contract that the contractor draw up comprehensive records of all pi.Ling work, and that such records be certified by the engineer (if acceptable). Such records should then form part of the contract records for technical and measurement purposes. The contractor is required

29、to keep records, as indicated in Table 3 of SABS 1200 F, of the installation of each pile, and he should submit two signed copies of each to the engineer not later than noon of the working day following the day on which the pile was installed. The engineer should certify his approval of the records,

30、 retuxn a copy to the contractor and retain the other copy as his record of the work, and for interim and final payments. Unexpected conditions and unidentified obstructions encountered should be confirmed in the report, but such confirmation will not absolve the contractor from the obligation to gi

31、ve immediate notice, as required in terms of Subclauses 5.1.7.1 and 5.8 of SABS 1200 F. Tests and Interpretation of Danish Test Curves (Subclause 7.5). Typical curves derived during tests to failure of piles, are shown on Drawing F-5.1 for predominantly friction piles and for predominantly end-beari

32、ng piles. The two most significant aspects of the Danish test are that it can be completed on a normal working pile in one day, and that the skin frictlon can be determined. In order to reap these benefits for a normal workinq pile and subject to the enqineers discretion as results become available,

33、 provision has been made in Subclausa. 7.5 of SABS 1200 F for a uniform loading increment of 0,05 P to be used in Stages 11-IV and for the final load to be held in each of these stages for only 1 h under normal circumstances. An analysis and an Interpretation of the load/deflection curves produced d

34、uring a test by the Danlsh method are given in (a), (h), and (c) below, as well as a method of calculating the toe load at each stage of a test and of determining the ultimate toe load for a permanent set in the case of a typical end-bearing pile. (See also Subclause 3.2.4.2 of Section F of Part 2 o

35、f the code.) a) Figure 1 shows curves of load against deflection at a particular time (15 min) after the application of each load. The load at the toe of the pile may be calculated for each stage of loading corresponding CO a permanent set (resultant deflection after removal of load) dl, d2, d3, and

36、 d on the graph given in Fig. 1. 4 Fig. l - Load against Deflection 5 9 ;i- S 8 l I l I l d2 “3 4 PERMANENT SETiRESULTANT DEFLECTIONS) Fig. 2 - Toe load against Permanent Set b) When these permanent set polnts are plotted against the corresponding toe loads, a curve of the form Pt = PA (1 - e -ad) i

37、s obtained as in Fig. 2. where P, = toe load I = the portlon of the fallure load carried at the toe of the pile A e = 2,718 a = a constant depending on the design of the pile and the soil conditions d = the permanent set By using the known values of It and d at thr points X and I on the graph, value

38、s for P and a may be calculated from the equation. A c) To interpret the results of the tests and to determne whether a pile meets the acceptance criteria, substitute values for P and PS (skin friction, obtained as shown in Fig. 1) in the following formula and A determine an ultimate toe load value

39、(I“ ) for a permanent set equal to, say, 10 X of the pile diameter: Where a test load 1,5 times the nominal load given in the contract document, the engineer will expect the graph of load against deflection to yield the initial straight portion of the curves only, in which case the nominal load may

40、be regarded as the safe load. NOTE: Where necessary, the safe load-carrying capacity at the acceptable settlement of each pile may be determined from the curves derived during the pile test(s) carried out in terms of Clause 7 of SABS 1200 F. SABS 0320 : Part 5 Section F-1983 Piling Guarantee (Subcla

41、use 7.8.1). Where consideration is being given to acceptance of a load-carrying - capacity that is less than the nominal load for the purposes of Subclause 7.8.1 of SABS 1200 F, the safe load of each pile should be determined after the necessary action has been taken in terms of Subclauses 7.3.2 and

42、 7.7 of SABS 1200 F. (See also Subclauses 1.3.7 and 2.2.2 of Section F of Part 3 of the code.) Standing Time (Subclause 8.2.3). The engineer should be informed immediately any circumstances arise that, in the contractors opinion, warrant a claim for standing time. This will enable the engineer to re

43、cord the circumstances (without necessarily conceding the justification for such a claim) and to deal with the alleged source of the delay. METHODS OF CONSTRIJCTION Piling Hammer, Leaders, and Protection Devices (Clause 4). The piling hammer should be of such design that it does not damage any perma

44、nent component of the pile during driving operations. It may operate under gravity or have a self-contained power drive with a rapid action. Inclined leaders should be used when driving raking piles. They should be so constructed as to afford freedom of movement of the hammer and should be so held i

45、n position as to ensure adequate support for the pile or pile casing during installation. Helmets and dollies should be provided as required. Helmets should be of steel and of an approved make. Each dolly should be of an approved type, should consist of yielding material, and should fit the top of t

46、he pile sufficiently accurately to ensure that hammer-blow stresses are evenly distributed. If the material of a dolly becomes compacted it should be renewed before damage is caused to the pile. Subsoil Conditions Differ Materially from those Shown on Drawings (Subclause 5.1.7) Contractor notifies e

47、ngineer. Where the contractor notifies the engineer that the subsoil conditions differ clearly from those shown on the drawings, a) the enqineer should decide as quickly as possible on the action to be taken or any additional tests required and, as test results become available, he should issue suit

48、able orders to ensure that delays and disruption of the work program are minimized (see 3.1.2 above); and b) the contractor should advise the engineer (within 14 d, preferably) if he intends to lodge a claim in terms of the conditions of contract (see Subclause 1.3.2 of Section F of Part 3 of the co

49、de, and 3.1.11 above) . Amended founding levels (Subclause 5.1.7.1). Where the enqineer wishes to verify the conditions at the intended founding level to establish whether a shallower or deeper founding level is feasible or necessary, he may, in terms of Subclause 5.1.7.1 of SABS 1200 F, require the contractor to carry out additional subsoil investigation work during the course of construction. The cost of such work will be covered by extra payments. Expeditious Augering and Boring of Pile Moles (Subclause 5.2.1). In addition to being necessary because of the proximity or condition o