The conjugatebeam method is an engineering method to derive the slope and. Towards a mechanistic analysis of benkelman beam deflection. The movement at the dial gauge end of the beam is onehalf of that at the contact point end. Published reports omitted important considerations which could influence measurement by the benkelman beam of deflection and curvature of flexible pavements under load. Whenever new pavement is to be laid this reading is helpful. The rebound deflection measured deflection and characteristic deflection computed as per irc. Backanalysis of a measured deflection bowl is a widely accepted method for estimating the existing pavement materials elastic properties this is required for undertaking the rehabilitation treatments mechanistic design. The slope, deflection, reactions, internal shear and bending moment of a beam that simultaneously supports several. 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.
Benkelman devised the simple deflection beam in 1953 for measurement of pavement surface deflection on the washto test road. Beam deflections double integration method example part 1. Deflection of a beam by successive integration physics. Benkelman beam deflection studies linkedin slideshare. A new technique for large deflection analysis of non. This pavement analysis tool provides the following features. A method for determining allowable spring deflection with the benkelman beam was developed from a literature survey and from a closely related field study.
Our pdf merger allows you to quickly combine multiple pdf files into one single pdf document, in just a few clicks. Directreading dial indicator eliminates need for conversion tables or field calculations. Moment method the areamoment method of determining the deflection at any specified point along a beam is a semi graphical method utilizing the relations between successive derivatives of the deflection y and the moment diagram. Beam deflections double integration method example part 3.
Researches performed this direction revealed that it is a clear dependency between deflection and frequency changes, what makes deflection an important feature of beam behavior, usable in damage assessment. Nov, 2012 beam deflections double integration method example part structural analysis. Stress and deflection beam both ends overhanging supports. Example of double integration method for beam deflections. General a the surface under the beam shall be sound and free of excessive loose material, large protruding. Advantages of the benkelman beam include ease to use, low equipment cost, and large database can be. Beam deflection using spreadsheet tools for successive. Beam deflections double integration method example part.
The following survey and tests will be conduct to compare deflection of flexible pavements by bbd and fwd techniques. Networklevel studies of pavement structure are being performed but have major limitations such as lack of accurate measurements, no true deflection is measured at any. Benklemam beam is one of the most commonly used methods for measuring deflection of the pavement surface. 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. Pdf mechanistic design of overlay based on benkelman. Standard test procedure for benkelman beam deflection. Collection and interpretation of pavement structural. Combining pdfs with a zipper method is useful in a variety of situations. It should be used to find out the overlay thickness of the flexible over flexible pavement as per irc81 1997. One of the easiest and convenient ways of designing an overlay for strengthening is by using benkelman beam deflection bbd technique which measures the rebound deflection of the pavements. The after successfully completing this chapter you should be able to. Tapered beams deflect as a result of shear deflection in addition to bending deflections figs. The relationship between changes of deflection and natural.
Combines pdf files, views them in a browser and downloads. Method aims determine the slope and deflection by using moment area method expected outcomes. Benkelman beam deflection measurements waka kotahi nz. Development correlation between benkelman beam deflection and. Pavement deflection is measured by the benkelman beam which consists of a slender beam 3. Csi software uses a momentarea technique to calculate deflection during composite design. Helpful article on how to merge pdf files in different ways with pdf24. The results showed that the values read on the beam in the case of the load of. Hibbeler, 7th edition, prentice hall structural analysis, hibbeler, 7th edition, prentice hall. Multiple pdfs can be combined into a single pdf from within revu or from the context rightclick menu in windows explorer. Results of deflection measurement by benkelman beam method and determination of the characteristic deflection the results of the deflection measurements from the fatickkaolack road with modulation of the axle load of 10, and 16 tons are given in table 1. Benkelman beam for flexible pavement deflection testing.
Creating a pdf from multiple pdfs bluebeam technical support. Introduction the benkelman beam instrument is used to measure the deflection of the road. In this method, the deflection of the beam at any point is made equal to the resultant of deflections at that specific point created by the every load acting on the beam individually. Although most mechanics of materials texts include a number of beam deflection solution methods, students are normally shown only one, or possibly two methods due to course time constraints. Fo r problems involving several changes in loading, the areamoment method is. Comparative studies between benkelman beam deflections bbd.
Rl rr mftrftlr01 15 1 r 15 r 1 l 15 r using the method of section the virtual moment expressions are. Referenced documents purchase separately the documents listed below are referenced within the subject standard but are not provided as part of the standard aashto standard. Benkelman beam test is one the static load deflection equipment which measures the maximum deflection response of a pavement to static or slowly applied loads. Engineers recognize the usefulness of pavement deflection data to evaluate and monitor pavement response and existing pavement structural conditions. This test procedure covers the determination of the rebound deflection of a pavement under a standard wheel load and tyre pressure, with or without temperature measurements.
It was decided that 8 sets of observations of the benkelman beam deflection test may be taken. Comparative studies between benkelman beam deflections. The formulation is based on representing the angle of rotation of the beam by a polynomial on the position variable along the deflected beam axis. This test method sets out the procedure for measuring the rebound deflection of a flexible pavement or road formation using a portable deflection beam under both a standard wheel load and tyre pressure. To determine the rebound deflection of a pavement under a standard wheel load and tyre pressure with or without temperature measurement by benkelman beam test. Overlay design by benkelman beam road surface standard. This paper studies the very large deflection behavior of prismatic and nonprismatic cantilever beams subjected to various types of loadings. For common cases in which beams exhibit composite behavior, this method is effective however, when beams deflect upward under conditions of double or triplecurvature with tension along the top fiber, behavior may not be composite. Deflection during composite design technical knowledge.
History of benkelman beam deflection technique1 devised by a. Experimental setup of benkelman beam deflection equipment the arrangement was made for benkelman beam deflection test on runway for evaluation of structural capacity of existing flexible pavement. Figure 3 mounting brackets for benkelman beam f tape measure and pavement marker 1 chalk, paint or some other method of marking the pavement locations. Able to analyze determinate beam deflection and slope by moment area method. Deflection of beam theory at a glance for ies, gate, psu 5. Beam deflection is a topic normally included in undergraduate mechanics of materials courses. You can merge the multiple pdf document using merge method of pdfdocumentbase class, by specifying the path of the documents in a string array. The order of the files specified in the array are the order in. The most widely used method in india has been benkelman beam deflection bbd method. Determine the displacement and slope at point a on the beam i 1,000 in4, and e 29103 ksi. Introduction as students study beam deflections in engineering and in engineering technology, they are introduced to the method of successive integration which starts with the following general equation 234. The benkelman beam measures the deflection of a flexible pavement under moving wheel loads. Definition of method of determining beam deflections.
Both the fwd and instrumented benkelman beam are used in new zealand to measure the deflection bowl. Structural beam deflection, stress, bending equations and calculator for a beam supported both ends overhanging supports symmetrically, uniform load. Pdf mechanistic design of overlay based on benkelman beam. Use the mergepdfs method to merge the specified pdf files into a single output file. The superposition method is one of the best techniques for finding the deflection of the beam.
This investigation failed to find such a correlation but did indicate that the benkelman beam can be a useful tool in pavement. Horizontalreading, digital gauge for use with the benkelman beam. Develop the general equation for the elastic curve of a deflected beam by using double integration method and areamoment method. Strength evaluation of flexible pavement of runway using. The pdf24 online tools allow you to quickly and easily merge pdf files. Direct reading dial indicator eliminates need for conversion tables or field calculations. By suitably placing the probe between the dual wheels of a loaded truck, it is possible to measure the rebound and residual deflections of. Development of a laserbased sensor to measure true road.
Let us consider a deflection of a simply supported beam which is subjected to a concentrated load w acting at a distance a from the left end. Bending deflection method of superposition tu delft. Benkelman beam deflection, falling weight deflectometer, conventional whitetopping. Fwd deflection by using the deflection at the load center, while the bb rebound deflection using pavement rebound deflection bina marga, 2005. For instance, if the benkelman beam deflection is 0. This video lecture, part of the series structural analysis video lessons by prof. Conversely, the deflection of a beam can be calculated if the value of the abscissa is known. Pavement evaluation by benkelman beam of state highway. Deflection should be find out by benkelman beam deflection test. Area moment method memorial university of newfoundland. If stressstrain behaviour of the beam material remains linear elastic, principle of superposition applies. The deflection is measured from the original neutral surface of the beam to the neutral surface of the deformed beam. Beam deflections double integration method example.
Beams 3 beam deflection 3 beam deflection central point load 4 design buckling resistance moment of an unrestrained steel beam 5 steel beam with central lateral restraint 6 buckling resistance of a steel beam 8 laterally restrained steel floor. If you have watched this lecture and know what it is about, particularly what civil engineering topics are discussed, please help us by commenting on this video with your suggested description and title. Examples to eurocode steel design to en 1993 bs en page. Nov 14, 2012 finishing up the example problem for the beam deflection calculation using the double integration.
Standard guide for general pavement deflection measurements. Deflectometer rdd, benkelman beam deflectometer bbd. In order to know the strength of pavement section in the interval of 50. Pavement evaluation and measurement of functional and structural. Thus, in many situations it is necessary to calculate, using numerical methods, the actual beam deflection under the. For a beam with a variable 1 the appropriate deflection equation is x2\ ox pag oc p fsxl2. Measures the deflection of a flexible pavement under moving wheel loads. It consists datum frame supported on a rear leg with provision for quick adjustment screws, a slender beam of total length 3. D4602 guide for nondestructive testing of pavements using cyclicloading dynamic deflection equipment. And strengthening is the most adopted method as a pavement maintenance measure. Mechanistic design of overlay based on benkelman beam deflection technique a case study of rajkotmorbi state highway24 conference paper pdf available april 2015 with 3,989 reads.
However, at the 95 percent confidence level the bearing value of the section in. Evolution of the deflection according to truck overloading. Hence a 5m span beam can deflect as much as 20mm without adverse effect. Pddx pavement deflection data exchangetechnical data guide, version 1. Benkelman beam deflection testing was done to measure the characteristic deflection of the pavement surface and fifth wheel bump integrator was used to calculate the roughness index to assess the performance of the pavement. Benkelman devised the simple deflection beam in 1953 for measurement of pavement surface deflection on. T256standard method of test for pavement deflection measurements. The load on the dual wheel can be in the range of 2.
It is widely used all over the world for evaluation of the. The direct integration method may become more involved if the expression for entire beam is not valid for the entire beam. Benkelman beam evaluation of structural capacity of existing pavement estimation and design of over lay for strengthening of weak pavement 5. The a pprox imation that the rail is con tinuously supported improv es as the crosstie spacing decreases a nd as the rail bending sti ffness increase s i. D4694 test method for deflections with a fallingweighttype impulse load. Design of overlay for flexible pavement civil iitb. Thus, in many situations it is necessary to calculate, using numerical methods, the actual beam deflection under the anticipated design load and compare this figure with the. It should be used to find out the overlay thickness of the. All the following matlab code files are stored in a single directory. Benkelman beam deflection measurements 5 pages, 40 kb. Benkelman beam deflection method for evaluation of structural capacity of existing flexible pavements and design of overlay phase 1 this paper reports on the first phase of a study of the benkelman beam method, sponsored by the indian ministry of surface transport. Beam deflection and stress formula and calculators.