The beam test shall be as per nzta specification t1 except that the recordings for bowl deflection shall not be recorded or used in. This method of measurement enables the direct determination of the actual deflection bowl under a slowly moving load, but requires a benkelman beam with the. The most commonly used static deflection device is the benkelman beam. Benkelman beam deflection studies linkedin slideshare. Benkelman beam is less expansive deflection measuring equipment and method of study is simple and easy to carry out. The method also describes the procedure for the calibration of the benkelman beam and the rotopulse transducer which determines the spacing at which the data is logged. Hibbeler, 7th edition, prentice hall structural analysis, hibbeler, 7th edition, prentice hall. The most widely used method in india has been benkelman beam deflection bbd method.
Pdf mechanistic design of overlay based on benkelman beam. Draw the m diagram by parts, starting from midspan toward the ends. Deflection method date page 2001 03 15 1 of 2 infrastructure introduction this section presents the overlay design procedure based on the analysis of benkelman beam rebound deflection testing. Calculation of deflections and redundant reactions for beams on two supports can be made by the use of the areamoment method.
Home asphalt road quality testing benkelman beam benkelman beam for flexible pavement deflection testing. The deviation of any point b relative to the tangent drawn to the elastic curve at any other point a, in a direction perpendicular to the original position of the beam, is equal to the product of 1ei multiplied by the moment of an area about b of that part of the moment diagram between points a and b. Geometry of the structure, including shape and flexural rigidity of member. The various parameters like pavement surface temperature, subgrade soil type, its moisture content and compaction. Benkelman beam for flexible pavement deflection testing. This distance is frequently called the ttildititangential deviation to distinguish it from the beam deflection. The benkelman beam is used with a loaded truck typically 80 kn 18,000 lb on a single axle with dual tires inflated to 480 to 550 kpa 70 to 80 psi.
So, if n 0 or du dx vanishes at one end, say x 0, d 1 0 and automatically n 0 is satis ed at the other end, x l. The magnitude of rebound deflection of a flexible pavements when a standard wheel load of truck is moved forward is measured. The entire apparatus, must be sturdy, rigid and without slop. The force system created by the virtual loads is called. Definition california bearing ratio is the ratio of force per unit area required to penetrate in to a soil mass with a circular plunger of 50mm diameter at the rate of 1. Design of overlay for flexible pavement civil iitb. Performance of these roads will be monitored for a period of about three years. Appartus moulds 2250cc capacity with base plate, stay rod and wing nut confirming to 4. The one of the method for finding the deflection of the beam is the direct integration method, i. Surface deflection data from 320 mm thick conventional whitetopping overlay test sections at pune city, india was obtained using nondestructive test of. Deflection data acquisition system ddas and bwl4 manual, queensland. However, at the 95 percent confidence level the bearing value of the section in. Comparative studies between benkelman beam deflections bbd and falling weight deflect meter fwd. Part 2 unit load method aims determine the slope and deflection by using unit load method expected outcomes.
A method for determining allowable spring deflection with the benkelman beam was developed from a literature survey and from a closely related field study. Beam deflections double integration method example. Larger pavement deflections imply weaker pavement and subgrade. The requirements of a typical benkelman beam as shown in figure 4 are listed in test methods t160 and t199. In order to prevent the rigid body translation, one end of the beam. Pdf pavement rehabilitation design based on maximum. Measurement is made by placing the tip of the beam between the dual tires and measuring the pavement surface rebound as the truck is moved away see figure 17. Able to analyze determinate beam deflection and slope by moment area method. Strength evaluation of flexible pavement of runway using. Horizontalreading, digital gauge for use with the benkelman beam. For the love of physics walter lewin may 16, 2011 duration. Able to analyze determinate beam deflection and slope by unit load method references mechanics of materials, r. Deflectometer rdd, benkelman beam deflectometer bbd. Towards a mechanistic analysis of benkelman beam deflection.
Pavement evaluation by benkelman beam of state highway. Comparative studies between benkelman beam deflections. Vetrivel page 1 922011 proproproproccccedureedureedureedure for finding out the deflection of beam by macaulays method for finding out the deflection of beam by. Steplover by bella jewel download pdf deluxe siberia. Benkelman beam consist of slender beam of length 3. The deflection is obtained by integrating the equation for the slope. Benkelman beam as described in the csir manual k16 7, as illustrated in figure 4. The deflection of the loaded beam can be obtained various methods. Diagram showing critical dimensions of benkelman beam 2. Methods actually calculate the deflections in the pavements. The deflection will depend on the following factors.
Determine the slope and deflection by using moment area method expected outcomes. If the highest or the lowest deflection values for the section differ from the mean by more than onethird of the mean, then extra deflection measurement should be made at 25 m on either side of point where high or low values are observed. The modulus of elasticity is 205 gpa and beam is a solid circular section. Deflection of beam theory at a glance for ies, gate, psu 5. Beam deflections double integration method example part structural analysis. Pdf conventionally in india overlay of flexible pavement design is. Interpretation of falling weight deflectometer data. Beam, deflection, stress, strain equation and calculators strength mechanical of materials. Benkelman beam deflection bbd technique is widely used all over the world for evaluation of structural capacity of existing flexible pavements and also for estimation and design of overlays for strengthening of any weak pavement. Benkelman beamauxiliary instrument of the maintenance engineer. Deflection testing of earthwork and pavement layers roads and. Areamoment method to calculate deflections in beams. In so me countries the socalled rebound m ethod of measurement is used.
Load analysis types of loads dead loads, live loads, impact loads, wind loads, earthquake, hydraulic forces, etc. The method also describes the procedure for the calibration of the deflection data acquisition system ddas and bwl4 manual, queensland. History of benkelman beam deflection technique2 development of methods such as benkelman beam deflection method for evaluation of structural capacity of existing flexible pavements and also for estimation and design of overlays for strengthening of any. The benkelman beam deflection method is thus widely used for evaluation of structural capacity of existing flexible pavements and also for estimation and design of overlays for strengthening of any weak pavement for highways. Derivation of the weak form for the eulerbernoulli beam. Measures the deflection of a flexible pavement under moving wheel loads. The force is called the dummy loador the virtual load. Static load deflection equipment measures the maximum deflection response of a pavement to static or slowly applied loads. The original deflection measuring method, using the benkelman beam adopted on washo road test fig. To compute a component of deflection by the method of virtual work, the designer applies a force to structure at the point and in the direction of the desired displacement. Its used to measure the structural capacity of a flexible pavement. Beam deflections double integration method example part. Dimensions a and b must be recorded on form bb1 for each beam together with the benkelman beam no.
Steplover by bella jewel download pdf deluxe siberia rally seriale ultime fitness november 25, 2017 9. For instance, if the benkelman beam deflection is 0. Benkelman beam evaluation of structural capacity of existing pavement estimation and design of over lay for strengthening of weak pavement 5. The analytical procedure for correcting the deflection reading based on temperature, moisture content, soil type and plasticity limit is provided in the guidelines for strengthening of flexible road pavements using benkelman beam deflection technique, irc81. Calculate the slope and deflection at the free end. Pavement evaluation and measurement of functional and structural. By suitably placing the probe between the dual wheels of a loaded truck, it is possible to measure the rebound and residual deflections of the pavement structure. Deflection should be find out by benkelman beam deflection test.
Problem 653 beam deflection by conjugate beam method. Overlay design by benkelman beam road surface standard. Standard test procedure for benkelman beam deflection. The integration constant d 0 is undetermined meaning that the rigid body translation of the entire beam is allowed. Pavement deflection is measured by the benkelman beam which consists of a slender beam 3. The beam pivot bearing and the dial gauge must move freely without friction or slop. Mechanistic design of overlay based on benkelman beam deflection technique. Information on structural health condition can be extracted from analysis by backcalculation of the fwd data. Road pavement using benkelman beam deflection bbd technique. Benkelman beam deflection and roughness studies using bump integrator on various roads before and after the laying of micro surfacing, were also carried out.
1247 1026 1104 682 1313 25 1578 249 315 311 1505 1259 1329 1351 1559 494 346 910 1513 791 559 657 1326 105 874 630 1265 1471 236 1177 852 1321 1270 4 886 1322 830 304 59 1083 829 171 1046 554 1063 1003 1157 196 1156