Issue 1

Rollover protective structures play a vital role in protecting the operators of large earthmoving machines which are commonly used in the rural and mining sectors. These structures typically consist of a moment resisting steel frame that is required to withstand the impact forces sustained by the vehicle during a rollover and provide a survival space for the operator during such an event. Recent advances in analytical modelling techniques have made it possible to model accurately the response behaviour of these types of structures when subjected to load and energy requirements according to current performance standards adopted both in Australia and internationally. This paper is concerned with the response behaviour of a rollover protective structure (ROPS) fitted to a 125t rigid frame dump truck. Destructive experimental testing which involved the application of static loads to simulate the impact forces created during a rollover has been conducted on a 1/2 scale model ROPS for this particular vehicle. The testing program has involved complete instrumentation of the ROPS to enable corresponding member stresses and deflections to be recorded. In addition to this, non-linear finite element analysis has also been performed on this ROPS using the FEA software package ABAQUS version 6.3. The first stage of this computer analysis involved subjecting the ROPS to static loads about the lateral, vertical and longitudinal axes of the ROPS and comparing, results with those obtained from the experimental investigation and calibrating the computer model. Further research will involve using the calibrated finite element models to carry out dynamic simulations incorporating energy absorbing devices in the ROPS to optimise the level of energy absorption and enhance performance and operator safety. B. J. Clark, BE Hons, PhD, MIEAust Queensland University of Technology, Brisbane, Queensland, Australia Prof. David P. Thambiratnam, BSc(Eng) Hons, MSc, PhD, CPEng, FICE, FASCE, FIEAust Queensland University of Technology, Brisbane, Queensland, Australia N. J. Perera, BSc(Eng) Hons, CPEng, FIStructE, FIEAust Managing Director, Bird & Marshal Ltd, U.K.

This paper presents a study on mitigating the seismic response of shear wall structures by using dampers strategically located within them. The stiffness of the cut out section of the shear wall is replaced by the stiffness and damping of the device. Friction, viscoelastic and hybrid dampers in different configurations and at different locations are used to evaluate the peak deflections and accelerations, under several earthquake records. Results from this conceptual study have demonstrated the feasibility of using these dampers to mitigate the adverse seismic effects of these structures for a range of excitations, even when the dominant seismic frequencies match the natural frequency of the structure. Julius Marko, BE (Civil) School of Urban Development, Queensland University of Technology,Brisbane, Queensland, Australia Prof. David P. Thambiratnam, BSc(Eng) Hons, MSc, PhD, CPEng, FICE, FASCE, FIEAust School of Urban Development, Queensland University of Technology, Brisbane, Queensland, Australia N. J. Perera, BSc(Eng) Hons, CPEng, FIStructE, FIEAust MD, Bird & Marshal Ltd, UK

A research programme was initiated by the University of Queensland, Main Roads Queensland and Australian Standards committee CE/25 to investigate the adequacy of design provisions and performance of sinusoidal profile and ribbed profile steel helical culverts for a range of low covers (overburden fills). This paper reports on live load response of the culverts. The paper examines the response of 3m diameter sinusoidal profile and ribbed profile culverts with 900mm of cover. Each culvert was instrustructuralengineer mented with earth pressure transducers, displacement transducers and strain gauges. The test program measured significant bending strains in association with hoop strains on the culverts. The paper examines the distribution of the hoop and bending effects about the circumference to reveal a more pronounced difference in response between the two culvert types. There are also major differences between the measured behaviour of the two culverts and the assumed ring compression model used in many design standards and guidelines, including current Australian and British documents. R. W. Pritchard, BE, MEngSc, MIEAust Department of Main Roads, Queensland, Australia R. A. Day, PhD, DIC, MSc, BE, MIEAust Department of Civil Engineering, University of Queensland, Australia P. F. Dux, PhD, MEngSc, BE, FIEAust Department of Civil Engineering, University of Queensland, Australia K. Y. Wong, BE, PhD, FIEAust, FIEM RPM Engineers, Kuala Lumpur, Malaysia