Methods of measuring irregularities on surfaces of roads
BS 8420-2003 pdf free.Methods of measuring irregularities on surfaces of roads, footways and other paved areas using straightedges and wedges.
3.2.1 The type I straightedge (3.1.1) shall be used only in conjunction with wedge A (3.1.2) and they shall be permanently marked with the same unique reference.
3.2.2 Ensure that the surface to be measured is free from detritus.
3.2.3 Place the straightedge on the surface perpendicular to it. For longitudinal measurement, place the straightedge parallel to the centreline of the road. For transverse measurement, place it perpendicular to the centreline of the road.
NOTE The straightedge may be moved across the lane width and construction .jointa to determine the greatest irregularity. It may be placed at any p1ace, in any direction unless a specific direction of measurement is required.
3.2.4 Place the wedge on the surface so that full contact with the surface is obtained. Ensure that the wedge is perpendicular to the measurement edge of the straightedge.
3.2.5 Measure the distance between the measurement edge of the straightedge and the surface of the irregularity by inserting the wedge in the gap to refusal and then reading off the marked increments on the slope of the wedge.
3.2.6 Record the measurements to the nearest 1 mm.
3.2.7 For new surfaces, check conformity to irregularity criteria as soon as practicable after the surface has been laid.
NOTE I An example of irregularity criteria is SHW Cl 702: refer to Volume 1 of the Highways Agency publication Munualafconfract document.s for highway works 121.
NOTE 2 On occasions it will not be possible to check compliance before trafficking so on these occasions record and report that traffic king had occurred prior to test.
The test report shall contain at least the following information:
a) test date;
b) serial number of the report:
c) reference number of the straightedge and wedge (see 3.2.1):
d) test location, e.g. road number, lane, chainage reference;
e) type of measurement, e.g. transverse;
1) transverse location of left-hand end of straightedge, e.g. 500 mm from kerh:
g) length of the straightedge used in the test;
h) greatest measurement to the nearest 1 mm:
I) whether the test surface has been trafficked;
j) signature of the person accepting the technical responsibility for the report.
NOTE For repeatability and reproducibility, the location of each measurement position should be recorded as accurately as possible.
4 Measurement using type 2 straightedge
NO1’K Guidance on the use of type 2 straightedges is given in A.2.
4.1 Apparatus
NO1’E All equipment should be calibrated in accordance with Annex B.
4.1.1 7vpe 2 plain straightedge, between I m and 4 m (in whole or half metres) long. It shall be of rigid construction such that its measurement edge does not deviate from a true plane by more than ±0.2 mm at any point in its operating position. The straightedge shall not deviate from straight along its length by more than I mmlm. The horizontal width of the measurement edge shall be not less than 3 mm. The measurement edge shall be identifiable.
NOTE A typical type 2 straightedge is shown in Figure 2.
4.1.2 Wedge B. not less than 200 mm in length and not less than 20 mm in width. It shall be permanently marked on the slope plane in increments of 1 mm and its true height shall be accurate at each marked increment to ±0.5 mm.
4.2 Test method
4.2.1 The type 2 straightedge (4.1.1) shall be used only in conjunction with wedge B (4.1.2) and they shall be permanently marked with the same unique reference.
4.2.2 Ensure that the surface is free from detritus. Place the straightedge on the surface, perpendicular to the centreline of the road and bridging the rut to be measured.
4.2.3 Place the wedge on the surface so that full contact with the surface is obtained. Ensure that the wedge is perpendicular to the measurement edge of the straightedge.
NO1’E Measurements may be taken from either side of the straightedge.
4.2.4 Measure the distance between the measurement edge of the straightedge and the surface of the rut by inserting the wedge in the gap to refusal to ascertain the greatest deviation and then reading the marked increments on the slope of the wedge.
4.2.5 Record the measurements to the nearest 1 mm.
The test. report shall contain the following information:
a) test date:
b) serial number of the report;
c) reference number of the straightedge and wedge (see 4.2.1);
d) test location. e.g. road number, lane, chainage reference;
e) type of measurement, e.g. longitudinal, diagonal, transverse;
I’) length of the straightedge used in the test:
g) whether the surface has been trafficked;
h) signature of the person accepting the technical responsibility for the report.
NOTE For repeatability and reproducibility. the location of each measurement position should be recorded as accurately as possible.
5 Measurement using type 3 straightedge
NOTE Guidauw oil the use of type 3 ahaightedgea t given iii A.3.
5.1 Apparatus
NOTE All equipment should be calibrated in accordance with Annex W
5.1.1 Type 3 straightedge with adjustable blocks, between 1 m and 4 m (in whole or half metres) long. It. shall be of rigid construction such that its measurement edge does not deviate from a true plane by more than ±0.2 mm at any point in its operating position. The straightedge shall not deviate from straight along its length by more than 1 mm)m. The horizontal width of the measurement edge shall be not less than 3 mm. The measurement edge shall be identifiable. The blocks shall be of equal dimensions and adjustable along the length of the straightedge and they shall not deviate from a true plane by more than ±0.2 mm.
NOTE A typical type 3 straighwdge and typical adjust-able blocks are shown in Figure 3.
5.1.2 Wedge A. in accordance with 3.1.2.
5.2 Test method
5.2.1 The type 3 straightedge (5.1.1) shall be used only in conjunction with wedge A (5.1.2) and they shall be permanently marked with the same unique reference.
5.2.2 Ensure that the surface is free from detritus. Place the straightedge on the surface and adjust the blocks so that they can sit on each edge of the old road surface and the straightedge is perpendicular to the line of the trench.
5.2.3 Measure the distance between the measurement edge of the straightedge and the surface of the trench reinstatement by inserting the wedge in the gap to refusal to ascertain the greatest or least deviation and then reading off the marked increments on the slope of the wedge.
5.2.4 Record the measurements to the nearest 1 mm.
5.3 Test report
The test report shall contain at least the following information:
a) test date;
b) serial number of the report;
c) reference number of the straightedge and wedge (see 5.2.1);
d) test location, e.g. road number, lane, chainage reference;
e) length of the straightedge used in the test;
f) greatest measurement to the nearest 1 mm;
g) signature of the person accepting the technical responsibility for the report.BS 8420 pdf free download.Methods of measuring irregularities on surfaces of roads