《BS-7941-2-2000.pdf》由会员分享,可在线阅读,更多相关《BS-7941-2-2000.pdf(14页珍藏版)》请在三一文库上搜索。
1、| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BRITISH STANDARD BS 7941-2:2000 ICS 17.040
2、.20; 93.080.20 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW Surface friction of pavements Part 2: Test method for measurement of surface skid resistance using the GripTester braked wheel fixed slip device Licensed Copy: London South Bank University, London South Bank Univer
3、sity, Fri Dec 08 11:01:02 GMT+00:00 2006, Uncontrolled Copy, (c) BSI This British Standard, having been prepared under the direction of the Sector Committee for Building and Civil Engineering, was published under the authority of the Standards Committee and comes into effect on 15 September 2000 BSI
4、 09-2000 The following BSI references relate to the work on this standard: Committee reference B/510/5 Draft for comment 97/108144 DC ISBN 0 580 33210 1 BS 7941-2:2000 Amendments issued since publication Amd. No.DateComments Committees responsible for this British Standard The preparation of this Br
5、itish Standard was entrusted by Technical Committee B/510, Road materials, to Subcommittee B/510/5, Surface characteristics, upon which the following bodies were represented: County Surveyors Society Department of the Environment, transport and the Regions Institution of Civil Engineers Quarry Produ
6、cts Association Road Surface Dressing Association Society of Chemical Industry The following bodies were also represented in the drafting of the standard, through subcommittees and panels: Brick Development Association Britpave Department of the Environment, Transport and the Regions (Highways Agenc
7、y) Ministry of Defence Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 11:01:02 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7941-2:2000 BSI 09-2000i Contents Page Committees responsibleInside front cover Forewordii 1Scope1 2Terms and definitions1 3Equipment2 4
8、Calibration and maintenance3 5Test procedures3 6Sampling4 7Precision4 8Test results4 Annex A (informative) Water flow rates8 Figure 1 GripTester: General arrangement5 Figure 2 GripTester header file layout: ROADS VERSION 3.16 Figure 3 GripTester header file layout: AIRFIELDS VERSION 3.37 Licensed Co
9、py: London South Bank University, London South Bank University, Fri Dec 08 11:01:02 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ii BSI 09-2000 BS 7941-2:2000 Foreword This British Standard has been prepared under the direction of the Building and Civil Engineering Sector Policy and Strategy Committee
10、 by Subcommittee B/510/5, Surface characteristics. This standard is published in two parts. Part 1 is entitled Method for measuring the surface friction of pavements using a sideway force coefficient routine investigation machine. A British Standard does not purport to include all the necessary prov
11、isions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages 1 to 8, a
12、n inside back cover and a back cover. The BSI copyright notice displayed in this document indicates when the document was last issued. Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 11:01:02 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7941-2:2000 BSI 09-20001
13、 1 Scope This British Standard describes a method for determining the skid resistance of a surface using the GripTester continuous reading braked wheel fixed slip device. The method is applicable to the following: highways: surfacings; highways: horizontal signs; airport runways; flight decks; footw
14、ays; pedestrian precincts; test panels of surfaces intended for any of the above. The method is for measurement of skid resistance along a continuous surface on external paved surfaces or indoors. Test speeds can vary from 5 km/h to 130 km/h depending on the application. The measured values can be a
15、ffected by the test speed. 2 Terms and definitions For the purposes of this British Standard the following terms and definitions apply. 2.1 skid resistance property of the trafficked surface which limits relative movement between a vehicle tyre contact patch and the road 2.2 slip resistance property
16、 of the trafficked surface to maintain the adhesion of a pedestrian sole 2.3 frictional force tangential force generated between the vehicle tyre/pedestrian sole and the trafficked surface 2.4 braked wheel friction tester apparatus that can be moved over the test surface at a known, steady speed and
17、 that includes a test wheel, a system for braking the test wheel and instrumentation for measuring the resulting friction between the test tyre and test surface 2.5 fixed slip a braking system that forces the test wheel to roll at a fixed reduction of its natural speed 2.6 GripTester a braked wheel
18、fixed slip device friction tester capable of being manually pushed or towed at up to 130 km/h 2.7 load dynamic instantaneous vertical force acting on the test wheel 2.8 drag dynamic instantaneous horizontal force acting on the test wheel Licensed Copy: London South Bank University, London South Bank
19、 University, Fri Dec 08 11:01:02 GMT+00:00 2006, Uncontrolled Copy, (c) BSI 2 BSI 09-2000 BS 7941-2:2000 2.9 instantaneous friction reading drag divided by load 2.10 GripNumber mean of a number of instantaneous friction readings over a defined length NOTEThe range of the GripNumber is 0.00 to 1.20.
20、2.11 GripLength defined length over which the GripNumber is produced 2.12 water deposition system system for depositing a given amount of water in front of the test tyre so that it then passes between the tyre and the surface being measured 2.13 rate of water deposition rate at which water is deposi
21、ted on the surface to be measured in front of the test tyre 2.14 theoretical water film thickness thickness of the water film that would exist between a test tyre with smooth tread and the surface being measured if this surface had zero texture depth 2.15 routine skid resistance testing measurement
22、of the skid resistance of a surface in standardized test conditions, which normally include a defined rate of water deposition 2.16 operational skid resistance testing measurement of the skid resistance of a surface in response to an operational need and in whatever conditions exist at the time of t
23、he test, which may include contamination by ice, snow, slush or water NOTEThese tests do not include water deposition. 3 Equipment 3.1 Principle of operation The GripTester has two drive wheels and a single test wheel and is capable of being towed or manually pushed at speeds between 5 km/h and 130
24、km/h. It is illustrated in Figure 1. The test wheel is mounted on a stub axle and is mechanically braked by a fixed gear system with a ratio of 27:32 in relation to the drive wheels so that there is a relative slip speed between the drive wheels and the test wheel of just over 15 %. The drive wheel
25、tyres have a patterned tread and carry just over three quarters of the weight of the instrument: the test wheel tyre has a smooth tread. The two drive wheels are mounted on the main axle, which also carries a toothed wheel. A proximity sensor is mounted adjacent to this toothed wheel in such a way t
26、hat signals from this sensor can be transmitted to a signal processing unit (SPU) for the calculation of distance. Two strain gauge bridges on the stub axle continuously measure drag and load and transmit these signals to the SPU, which calculates the instantaneous friction readings. These readings
27、are sent in ASCII form to a data capture device where the GripNumber is computed and stored. If the GripTester is to be used for routine testing it shall be connected to a water tank fitted with a control valve. In towing mode, water deposition is further controlled by a pump and may be monitored wi
28、th a flowmeter. Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 11:01:02 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7941-2:2000 BSI 09-20003 3.2 Physical characteristics Overall length (excluding removable tow-bar)1 010 mm Overall width790 mm Overall height51
29、0 mm Test tyre 3 110“ diameter smooth tread as approved by the manufacturer Drive tyres 3 210“ diameter patterned tread as approved by the manufacturer Static load on test wheel under normal operating conditions Between 22 kg and 28 kg Data capture softwareAs provided by the manufacturer Data captur
30、e deviceVarious non-proprietary portable computers may be used 4 Calibration and maintenance 4.1 General principles The time-based schedule of inspection, calibration and maintenance set out in the manufacturers current manual shall be adhered to. 4.2 Routine procedures 4.2.1 A pre-survey check shal
31、l be carried out in accordance with the manufacturers current manual before and after testing on each day of the survey. 4.2.2 The monthly maintenance procedure shall be carried out in accordance with the manufacturers manual not more than one month prior to the survey. 4.2.3 The annual maintenance
32、procedure shall be carried out in accordance with the manufacturers manual not more than one year prior to the survey. 4.2.4 Full records shall be kept of the dates and details of all inspections and calibrations. 4.3 Special procedures When required, the accuracy of distance measurement shall be ch
33、ecked and calibrated in accordance with the manufacturers instructions. NOTESince speed measurements are derived from distance measurements, regular calibration of distance measurement is recommended. 5 Test procedures 5.1 Safety When carrying out a friction survey on trafficked roads, the GripTeste
34、r can operate at speeds different from normal road speed and as a result can create a hazard to other road users. It is essential that attention is paid to working in accordance with all current safety measures and those required by current legislation. When carrying out a friction survey at an airp
35、ort, ensure that all activities are under the control of the airport operators. Avoid carrying out tests involving water deposition if there is a risk of water freezing on the pavement. 5.2 Routine testing 5.2.1 General Wherever possible, the surface to be measured should be free from standing water
36、, frost, grease, debris or other contamination. The water deposition system shall be set up to provide the required water deposition rate. NOTESuggested guidelines for water deposition rates are given in annex A. The temperature of water applied shall be not less than 5 8C and not greater than 25 8C
37、. Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 11:01:02 GMT+00:00 2006, Uncontrolled Copy, (c) BSI 4 BSI 09-2000 BS 7941-2:2000 5.2.2 Towing mode Prior to the first test, check that the measuring system has reached the appropriate stable state. This shall be
38、done by switching on the SPU for at least 5 min and towing the GripTester over at least 500 m with the water deposition system in operation. If possible, the surface used should be representative of that initially to be tested. With the water deposition system in operation, tow the GripTester smooth
39、ly and at a standard speed, operating the data capture device in accordance with the manufacturers instructions. Examples of standard speeds are: (205), (505), (655), (955) km/h. 5.2.3 Pushing mode Prior to the first test, check that the measuring system has reached the appropriate stable state. Thi
40、s shall be done by switching on the SPU for at least 5 min and pushing the GripTester over at least 20 m with the water deposition system in operation. The surface used shall be representative of that initially to be tested. With the water deposition system in operation, push the GripTester smoothly
41、 and at the standard speed of (61) km/h, operating the data capture device in accordance with the manufacturers instructions. 5.3 Operational testing 5.3.1 Towing mode Prior to the first test check that the measuring system has reached the appropriate stable state. This shall be done by switching on
42、 the SPU for at least 5 min and towing the GripTester over at least 500 m. If possible, the surface used should be representative of that initially to be tested. Tow the GripTester smoothly and at a standard speed, operating the data capture device in accordance with the manufacturers instructions.
43、Standard speeds are: (205), (505), (655), (955) km/h. 5.3.2 Pushing mode Prior to the first test, ensure that the measuring system has reached the appropriate stable state. This shall be done by switching on the SPU for at least 5 min and pushing the GripTester over at least 20 m. NOTEIf possible, t
44、he surface used should be representative of that initially to be tested. Push the GripTester smoothly and at the standard speed of (61) km/h, operating the data capture device in accordance with the manufacturers instructions. 6 Sampling The GripTester shall be set to a sampling rate of 40 mm, 160 m
45、m, 400 mm or 800 mm. The data capture device shall be set to give a GripLength of between 40 mm and 10 m. The sampling rate and the GripLength shall be as specified by the client. 7 Precision Trials at the Transport Research Laboratory in May 1993 showed that for routine testing at 50 km/h with a wa
46、ter deposition rate of 18 l/min the repeatability of the GripTester was r = 0.02 and its reproducibility was R = 0.08. 8 Test results If the data capture device is used in accordance with the manufacturers instructions, the data file and the printed report will both contain all significant condition
47、s under which the test was carried out as well as the actual test results. The structure of the ASCII data files is defined in the manufacturers manual. Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 11:01:02 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7941-2
48、:2000 BSI 09-20005 Figure 1 GripTester: General arrangement Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 11:01:02 GMT+00:00 2006, Uncontrolled Copy, (c) BSI 6 BSI 09-2000 BS 7941-2:2000 Record no.Record nameComments/ details 0File format identifierData file i
49、n format: ROADS VERSION 3.1, units 1AuthorityKeyed in by operator: optional 2DateSupplied by system 3TimeSupplied by system 4GripTesterKeyed in by operator: mandatory 5Test tyreKeyed in by operator: mandatory 6SiteKeyed in by operator: optional 7SurfaceKeyed in by operator: optional 8DirectionKeyed in by operator: optional 9Lane/trackKeyed in by operator: optional 10Speed(km/h)Keyed in by operator: mandatory 11Water flow(l/m)Keyed in by operator: mandatory 12Operator/sKeyed in by operator: optional 13WeatherKeyed in by operator: optio
链接地址:https://www.31doc.com/p-3736258.html