http://hdl.handle.net/10204/4576 2013-05-18T13:32:30Z http://hdl.handle.net/10204/6428 Title: Toward using tire-road contact stresses in pavement design and analysis Authors: De Beer, M; Maina, JW; Van Rensburg, Y; Greben, JM Abstract: Optimization of road pavement design, especially towards the surface of the pavement, requires a more rational approach to modeling of truck tire-road contact stresses. Various road surfacing failures are given in this paper as examples, and it is shown that the traditional civil engineering tire model represented by a single uniformly distributed vertical contact stress of circular shape is inadequate to explain this type of surface failure. This paper therefore discusses the direct measurement of threedimensional (3D) tire pavement contact stresses using a flatbed sensor system referred to as the “Stress-In-Motion” (SIM) system. The SIM system (or device) consists of multiple conically shaped steel pins, as well as an array of instrumented sensors based on strain gauge technology. The test surface is textured with skid resistance approaching that of a dry asphalt layer. Full-scale truck tires have been tested since the mid-1990s and experience shows that 3D tire contact stresses are non-uniform and the footprint is often not of circular shape. It was found that especially the vertical shape of contact stress distribution changes, mainly as a function of tire loading. In overloaded/underinflated cases, vertical contact stresses maximize towards the edges of the tire contact patch. Higher inflation pressures at lower loads, on the other hand, result in maximum vertical stresses towards the center portion of the tire contact patch. These differences in shape and magnitude need to be incorporated into modern road pavement design. Four different tire models were used to represent a single tire type in order to demonstrate its effect on road pavement response of a typical South African pavement structure. Only applied vertical stress was used for the analyses. It was found that road surface layer life can reduce by as much as 94 percent as a result of simply using a different tire model on the same pavement structure. Description: Copyright: 2012 The Tire Society. This is an ABSTRACT ONLY. 2012-10-01T00:00:00Z http://hdl.handle.net/10204/6305 Title: Development of the tyre tester Authors: Kuduntwane, P; Du Plessis; Els, S Abstract: Improved mobility depends on simulating and analysing a vehicle’s performance. Therefore, accurate and efficient tyre models for off-road vehicles are needed. But to get that, we need a tyre tester for adjustable slip, camber and caster angles for improved tyre lateral data. Description: 4th CSIR Biennial Conference: Real problems relevant solutions, CSIR, Pretoria, 9-10 October 2012 2012-10-01T00:00:00Z http://hdl.handle.net/10204/6180 Title: The CSIR contribution to the Revision of the SA Road Pavement Design Method (SAPDM) Authors: Maina, J Abstract: In this presentation the author outlines the CSIR contribution to the Revision of South African Pavement Design Method. Description: 4th CSIR Biennial Conference: Real problems relevant solutions, CSIR, Pretoria, 9-10 October 2012 2012-10-01T00:00:00Z http://hdl.handle.net/10204/2944 Title: Feedback on the Inaugural Meeting of the Cost 347 Accelerated Loading Test (ALT) Action in Europe: June 27th to 29th 2001 Authors: De Beer, M Abstract: Describes in summary the attendance of the author at an invited meeting of the COST 347 ALT (Accelerated Loading Testing) Committee in Cologne, Germany, Europe. The meeting was held at Bast, near Cologne, from 27th June 2001 to 29th June 2001. The author presented two topics, i.e. Accelerated Pavement Testing (APT) in South Africa, and Stress-In-Motion (SIM). This COST 347 action started in October 2001, and needs to deliver recommendations on ALT April 2004. There are 6 Working Groups, chaired by several country members, working on the project. 2001-11-01T00:00:00Z