Hing-Ho Tsang

Shear and Compressibility Behavior of Sand–Tire Crumb Mixtures

AbstractScrap tire disposal has been a critical environmental problem in many urban cities due to the huge increase in the number of vehicles. Significant research efforts have been devoted in recent years to explore the use of scrap tires in civil engineering application, as reuse or recycling of scrap tires is the preferred option from a waste management perspective. This paper investigates shear and compressibility behavior of sand–tire crumb (S-TC) mixtures for their application in civil engineering projects. Unlike other studies where tire chips or tire shreds were used, shear strength of the S-TC mixtures has been found to decrease with the increase in the amount of tire crumbs in the mixtures. Significant increase in axial strain corresponding to peak deviator stress has been observed. This can be related to the ductility capacity of the mixtures, as confirmed by brittleness tests. It has also been observed that a larger proportion of plastic strain develops after the first cycle of unloading, and ...

Regional and local factors in attenuation modelling: Hong Kong case study

Seismic attenuation behaviour is controlled by a large number of wave modification mechanisms. The characteristics of some of these mechanisms are specific to a local area, whilst the remainder can be generalised to the entire seismic region. Factors representing these mechanisms are often not resolved. A new attenuation modelling approach is demonstrated in this paper (using Hong Kong as a case study), to evaluate individual regional and local wave modification factors. Shear wave velocity (SWV) information for the four prevalent geological formations found in Hong Kong was first obtained: (a) at shallow depths from instrumented boreholes; (b) at depths of up to 100–200 m from measurements using the Microtremor SPatial Auto-Correlation (SPAC) technique; (c) at depths of up to 1.5 km from the monitoring of quarry blasts; and (d) at depths from 1.5 to 8 km in the hard basement rock layers from results of seismological refraction surveys. The upper-crust amplification factor calculated from the four modelled rock SWV profiles was then combined with predicted attenuation parameters to determine the upper-crust modification factor (filter function) incorporating the local wave modification characteristics associated with Hong Kong geological formations. Such functions may then be combined with the regional attenuation characteristics in that part of the South China region. A seismic attenuation model was developed by combining the upper-crust modification factor with the regional source function of intra-plate earthquakes, based on stochastic simulations. The ground shaking model developed from the presented methodology is supported by the comparison with macro-seismic data of seven historical earthquake events affecting Hong Kong.

Conversion between peak ground motion parameters and modified mercalli intensity values

A model developed recently for conversion of instrumental data to Modified Mercalli Intensity data in North America has been evaluated in this study which employed strong motion recordings and matching Intensity data from ten Iranian earthquakes. Iranian data has also been used to develop new expressions for estimation of Intensity values for various peak ground motion parameters. Importantly, predictions from the new expression with peak ground velocity as the predictor is consistent with those from well-published models developed from data collected in North America. The demonstrated generality of existing conversion relationships has important implications to damage assessment across the globe.

Shear and compression characteristics of recycled glass-tire mixtures

AbstractTire particles in the form of shreds, chips, or crumbs, are normally mixed with sand to make suitable alternative backfill or embankment materials. This mixture of soft (tire) and rigid (sa...