The crystallographic texture and microstructure of electrogalvanized Zn layers on a mild steel cathode were studied with reference to the galvanizing variables including current density and chloride addition. Increasing the current density reduced the relative density of Zn basal planes parallel to the cathode surface. This phenomenon was attributed to the outgrowth of nonbasal planes within an ion-depleted zone close to the metal substrate surface under high cathode overvoltage induced by the high current density. Chloride addition also affected the cathode overvoltage and subsequently the texture of the Zn layer. The effect depended on chloride concentration and temperature. Increasing the current density or adding chloride enhanced the hardness of the electrodeposited layer, as a result of grain size refinement and solid solution hardening.

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Reinforcing end-cross beam and removing bumps at expansion joints of bridges are proposed to reduce the traffic-induced vibration and to enhance the deck resistance near the expansion joint of a two-girder steel bridge with elastomeric bearings at each support. The reduction effect is investigated by means of a three-dimensional traffic-induced dynamic analysis. This study indicates that traffic-induced acceleration responses as well as dynamic reaction force of the bridge with the elastomeric bearings are greater than those of the bridge with steel pin bearings. It is observed that reinforcing the end-cross beam reduces trafficinduced vibrations regardless of bearing types, and also removing bumps is the most effective in reducing the dynamic reaction force of the bridges. Especially, for the bridge with elastomeric bearings, the maintenance of bumps near expansion joints is very important to improve not only expanding life span of the expansion joint but also the vibration serviceability of bridges. #

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